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Sample records for diamond-like carbon coating

  1. A Preliminary Evaluation of Diamond-Like Carbon Coated Polycarbonate

    DTIC Science & Technology

    1991-09-01

    moisture sensitive coatings provide good protection against laser induced damage. Proper adhesion between each coating layers needs to be estab- lished... coating that is being pursued is to increase the wear, abra- sion, and chemical resistance of the current ballistic/laser protective spectacles (BLPS...unique ion beam system. These diamond-like carbon coatings have considera’le potential as wear-resistant protective hardcoatings for transparent

  2. Optically transparent, scratch-resistant, diamond-like carbon coatings

    DOEpatents

    He, Xiao-Ming; Lee, Deok-Hyung; Nastasi, Michael A.; Walter, Kevin C.; Tuszewski, Michel G.

    2003-06-03

    A plasma-based method for the deposition of diamond-like carbon (DLC) coatings is described. The process uses a radio-frequency inductively coupled discharge to generate a plasma at relatively low gas pressures. The deposition process is environmentally friendly and scaleable to large areas, and components that have geometrically complicated surfaces can be processed. The method has been used to deposit adherent 100-400 nm thick DLC coatings on metals, glass, and polymers. These coatings are between three and four times harder than steel and are therefore scratch resistant, and transparent to visible light. Boron and silicon doping of the DLC coatings have produced coatings having improved optical properties and lower coating stress levels, but with slightly lower hardness.

  3. Atmospheric Plasma Deposition of Diamond-like Carbon Coatings

    SciTech Connect

    Ladwig, Angela

    2008-01-23

    There is great demand for thin functional coatings in the semiconductor, optics, electronics, medical, automotive and aerospace industries [1-13]. As fabricated components become smaller and more complex, the properties of the materials’ surface take on greater importance. Thin coatings play a key role in tailoring surfaces to give them the desired hardness, wear resistance, chemical inertness, and electrical characteristics. Diamond-like carbon (DLC) coatings possess an array of desirable properties, including outstanding abrasion and wear resistance, chemical inertness, hardness, a low coefficient of friction and exceptionally high dielectric strength [14-22]. Diamond-like carbon is considered to be an amorphous material, containing a mixture of sp2 and sp3 bonded carbon. Based on the percentage of sp3 carbon and the hydrogen content, four different types of DLC coatings have been identified: tetrahedral carbon (ta-C), hydrogenated amorphous carbon (a-C:H) hard, a-C:H soft, and hydrogenated tetrahedral carbon (ta-C:H) [20,24,25]. Possessing the highest hardness of 80 GPa, ta-C possesses an sp3 carbon content of 80 to 88u%, and no appreciable hydrogen content whereas a-C:H soft possesses a hardness of less than 10 GPa, contains an sp3 carbon content of 60% and a hydrogen content between 30 to 50%. Methods used to deposit DLC coatings include ion beam deposition, cathodic arc spray, pulsed laser ablation, argon ion sputtering, and plasma-enhanced chemical vapor deposition [73-83]. Researchers contend that several advantages exist when depositing DLC coatings in a low-pressure environment. For example, ion beam processes are widely utilized since the ion bombardment is thought to promote denser sp3-bonded carbon networks. Other processes, such as sputtering, are better suited for coating large parts [29,30,44]. However, the deposition of DLC in a vacuum system has several disadvantages, including high equipment cost and restrictions on the size and shape of

  4. Diamond/diamond-like carbon coated nanotube structures for efficient electron field emission

    NASA Technical Reports Server (NTRS)

    Dimitrijevic, Steven (Inventor); Withers, James C. (Inventor); Loutfy, Raouf O. (Inventor)

    2005-01-01

    The present invention is directed to a nanotube coated with diamond or diamond-like carbon, a field emitter cathode comprising same, and a field emitter comprising the cathode. It is also directed to a method of preventing the evaporation of carbon from a field emitter comprising a cathode comprised of nanotubes by coating the nanotube with diamond or diamond-like carbon. In another aspect, the present invention is directed to a method of preventing the evaporation of carbon from an electron field emitter comprising a cathode comprised of nanotubes, which method comprises coating the nanotubes with diamond or diamond-like carbon.

  5. Diamond like carbon coatings: Categorization by atomic number density

    NASA Technical Reports Server (NTRS)

    Angus, John C.

    1986-01-01

    Dense diamond-like hydrocarbon films grown at the NASA Lewis Research Center by radio frequency self bias discharge and by direct ion beam deposition were studied. A new method for categorizing hydrocarbons based on their atomic number density and elemental composition was developed and applied to the diamond-like hydrocarbon films. It was shown that the diamond-like hydrocarbon films are an entirely new class of hydrocarbons with atomic number densities lying between those of single crystal diamond and adamantanes. In addition, a major review article on these new materials was completed in cooperation with NASA Lewis Research Center personnel.

  6. Compilation of diamond-like carbon properties for barriers and hard coatings

    SciTech Connect

    Outka, D.A.; Hsu, Wen L.; Boehme, D.R.; Yang, N.Y.C.; Ottesen, D.K.; Johnsen, H.A.; Clift, W.M.; Headley, T.J.

    1994-02-01

    Diamond-like carbon (DLC) is an amorphous form of carbon which resembles diamond in its hardness, lubricity, and interest for hardness, lubricity, and resistance to chemical attack. Such properties make DLC of use in barrier and hard coating technology. This report examines a variety of properties of DLC coatings which are relevant to its use as a protective coating. This includes examining substrates on which DLC coatings can be deposited; the resistance of DLC coatings to various chemical agents; adhesion of DLC coatings; and characterization of DLC coatings by electron microscopy, FTIR, sputter depth profiling, stress measurements, and nanoindentation.

  7. Load-Bearing Biomedical Applications of Diamond-Like Carbon Coatings - Current Status

    PubMed Central

    Alakoski, Esa; Tiainen, Veli-Matti; Soininen, Antti; Konttinen, Yrjö T

    2008-01-01

    The current status of diamond-like carbon (DLC) coatings for biomedical applications is reviewed with emphasis on load-bearing coatings. Although diamond-like carbon coating materials have been studied for decades, no indisputably successful commercial biomedical applications for high load situations exist today. High internal stress, leading to insufficient adhesion of thick coatings, is the evident reason behind this delay of the break-through of DLC coatings for applications. Excellent adhesion of thick DLC coatings is of utmost importance for load-bearing applications. According to this review superior candidate material for articulating implants is thick and adherent DLC on both sliding surfaces. With the filtered pulsed arc discharge method, all the necessary requirements for the deposition of thick and adherent DLC are fulfilled, provided that the substrate material is selected properly. PMID:19478929

  8. Compilation of diamond-like carbon properties for barriers and hard coatings

    SciTech Connect

    Outka, D.A.; Hsu, Wen L.; Phillips, K.; Boehme, D.R.; Yang, N.Y.C.; Ottesen, D.K.; Johnsen, H.A.; Clift, W.M.; Headley, T.J.

    1994-05-01

    Diamond-like carbon (DLC) is an amorphous form of carbon which resembles diamond in its hardness, lubricity, and resistance to chemical attack. Such properties make DLC of interest for use in barrier and hard coating technology. This report examines a variety of properties of DLC coatings. This includes examining substrates on which DLC coatings can be deposited; the resistance of DLC coatings to various chemical agents; adhension of DLC coatings; and characterization of DLC coatings by electron microscopy, FTIR, sputter depth profiling, stress measurements and nanoindentation.

  9. Adhesion, cytoskeletal architecture and activation status of primary human macrophages on a diamond-like carbon coated surface.

    PubMed

    Linder, Stefan; Pinkowski, Wolfhard; Aepfelbacher, Martin

    2002-02-01

    Diamond-like carbon is a promising surface coating for biomedicinal implants like coronary stents or hip joints. Before widespread clinical use of this material, its biocompatibility has to be thoroughly assessed. Cells likely to encounter a diamond-like coated implant in the human body are cells of the monocytic lineage. Their interaction with the diamond-like carbon coated surface will probably critically influence the fate of the implant, as monocytes orchestrate inflammatory reactions and also affect osseointegration of implants. We therefore investigated adhesion, cytoarchitecture and activation status of primary human monocytes and their differentiated derivatives, macrophages, on diamond-like coated glass coverslips using immunofluorescence technique. We show that adhesion of primary monocytes to a diamond-like-coated coverslip is slightly, but not significantly, enhanced in comparison to uncoated coverslips, while the actin and microtubule cytoskeletons of mature macrophages show a normal development. The activation status of macrophages, as judged by polarization of the cell body, was not affected by growth on a diamond-like carbon surface. We conclude that diamond-like carbon shows good indications for biocompatibility to blood monocytes in vitro. It is therefore unlikely that contact with a diamond-like carbon coated surface in the human body will elicit inflammatory signals by these cells.

  10. Advances in multi-spectral Diamond-Like Carbon (DLC) coatings

    NASA Astrophysics Data System (ADS)

    Keck, Jason; Karp, Christopher

    2014-05-01

    We discuss the development and applications of a new approach to Diamond-Like Carbon (DLC) coating that provides the durability of traditional DLC coatings, with the addition of significantly more transmission at visible wavelengths and greater transmission in the IR. We developed a deposition system design that incorporates multiple coating technologies, allowing for multiple material design approaches. This has enabled the manufacture of DLC coatings with improved extended spectral properties, suitable for applications in which the coating must withstand airborne particulate impacts, corrosive fluids, environmental extremes, and abrasive physical handling, while offering better than typical transmission in the visible or infrared wavelength regions, or both.

  11. Superlow friction behavior of diamond-like carbon coatings: Time and speed effects

    NASA Astrophysics Data System (ADS)

    Heimberg, J. A.; Wahl, K. J.; Singer, I. L.; Erdemir, A.

    2001-04-01

    The friction behavior of a diamond-like carbon coating was studied in reciprocating sliding contact at speeds from 0.01 to 5 mm/s, in dry nitrogen. "Superlow" friction coefficients of 0.003-0.008 were obtained in continuous sliding at the higher speeds (>1 mm/s). However, friction coefficients rose to values typical of diamond-like carbon in dry and ambient air (0.01-0.1) at lower speeds (<0.5 mm/s) as well as in time-delayed, higher speed tests. The rise of the friction coefficients in both speed and time-delay tests was in good quantitative agreement with gas adsorption kinetics predicted by the Elovich equation for adsorption onto carbon. More generally, superlow friction could be sustained, suppressed, and recovered as a function of exposure time, demonstrating that duty cycle cannot be ignored when predicting performance of superlow friction coatings in devices.

  12. Room temperature diamond-like carbon coatings produced by low energy ion implantation

    NASA Astrophysics Data System (ADS)

    Markwitz, A.; Mohr, B.; Leveneur, J.

    2014-07-01

    Nanometre-smooth diamond-like carbon coatings (DLC) were produced at room temperature with ion implantation using 6 kV C3Hy+ ion beams. Ion beam analysis measurements showed that the coatings contain no heavy Z impurities at the level of 100 ppm, have a homogeneous stoichiometry in depth and a hydrogen concentration of typically 25 at.%. High resolution TEM analysis showed high quality and atomically flat amorphous coatings on wafer silicon. Combined TEM and RBS analysis gave a coating density of 3.25 g cm-3. Raman spectroscopy was performed to probe for sp2/sp3 bonds in the coatings. The results indicate that low energy ion implantation with 6 kV produces hydrogenated amorphous carbon coatings with a sp3 content of about 20%. Results highlight the opportunity of developing room temperature DLC coatings with ion beam technology for industrial applications.

  13. Adherent diamond like carbon coatings on metals via plasma source ion implantation

    SciTech Connect

    Walter, K.C.; Nastasi, M.; Munson, C.P.

    1996-12-01

    Various techniques are currently used to produce diamond-like carbon (DLC) coatings on various materials. Many of these techniques use metallic interlayers, such as Ti or Si, to improve the adhesion of a DLC coating to a ferrous substrate. An alternative processing route would be to use plasma source ion implantation (PSII) to create a carbon composition gradient in the surface of the ferrous material to serve as the interface for a DLC coating. The need for interlayer deposition is eliminated by using a such a graded interfaces PSII approach has been used to form adherent DLC coatings on magnesium, aluminum, silicon, titanium, chromium, brass, nickel, and tungsten. A PSII process tailored to create a graded interface allows deposition of adherent DLC coatings even on metals that exhibit a positive heat of formation with carbon, such as magnesium, iron, brass and nickel.

  14. Corrosion behavior of titanium alloy Beta-21S coated with diamond like carbon in Hank's solution

    NASA Astrophysics Data System (ADS)

    Mohan, L.; Anandan, C.; Grips, V. K. William

    2012-06-01

    Diamond like carbon (DLC) coatings posses high hardness and low friction coefficient and also biocompatible, hence, they are of interest for enhancing the wear and corrosion resistance of bio-implant materials. Beta stabilized titanium alloys are attractive for biomedical applications because of their high specific strength and low modulus. In this work Beta-21S alloy (Ti-15Mo-3Nb-3Al-0.2Si) was implanted with carbon ions by plasma immersion ion implantation using methane and hydrogen gas mixture followed by DLC deposition by plasma enhanced chemical vapour deposition (PECVD). The implanted layers enabled deposition of adherent diamond-like carbon coatings on the titanium alloy which was otherwise not possible. The corrosion behavior of the treated and untreated samples was investigated through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies in simulated body fluid (Hank's solution). XPS, micro Raman and EDAX investigation of the samples showed the formation of a thin oxide layer on the treated samples after corrosion experiments. Corrosion resistance of the DLC coated sample is comparable with that of the untreated samples. Electrochemical impedance data of the substrate and implanted samples were fitted with two time constant equivalent circuits and that of DLC coated samples with two-layer model.

  15. Fluorine doping into diamond-like carbon coatings inhibits protein adsorption and platelet activation.

    PubMed

    Hasebe, Terumitsu; Yohena, Satoshi; Kamijo, Aki; Okazaki, Yuko; Hotta, Atsushi; Takahashi, Koki; Suzuki, Tetsuya

    2007-12-15

    The first major event when a medical device comes in contact with blood is the adsorption of plasma proteins. Protein adsorption on the material surface leads to the activation of the blood coagulation cascade and the inflammatory process, which impair the lifetime of the material. Various efforts have been made to minimize protein adsorption and platelet adhesion. Recently, diamond-like carbon (DLC) has received much attention because of their antithrombogenicity. We recently reported that coating silicon substrates with fluorine-doped diamond-like carbon (F-DLC) drastically suppresses platelet adhesion and activation. Here, we evaluated the protein adsorption on the material surfaces and clarified the relationship between protein adsorption and platelet behaviors, using polycarbonate and DLC- or F-DLC-coated polycarbonate. The adsorption of albumin and fibrinogen were assessed using a colorimetric protein assay, and platelet adhesion and activation were examined using a differential interference contrast microscope. A higher ratio of albumin to fibrinogen adsorption was observed on F-DLC than on DLC and polycarbonate films, indicating that the F-DLC film should prevent thrombus formation. Platelet adhesion and activation on the F-DLC films were more strongly suppressed as the amount of fluorine doping was increased. These results show that the F-DLC coating may be useful for blood-contacting devices.

  16. Electrical conditioning of diamond-like carbon films for the formation of coated field emission cathodes

    NASA Astrophysics Data System (ADS)

    Semenenko, M.; Okrepka, G.; Yilmazoglu, O.; Hartnagel, H. L.; Pavlidis, D.

    2010-11-01

    Diamond-like carbon (DLC) films deposited on different substrates by plasma enhanced chemical vapour deposition were investigated. Bonding states and film quality were characterized by FT-IR spectroscopy. The influence of the power of plasma and the deposition time on the sp2/sp3 ratio as well as the concentration of CHn bonds was studied. The influence of sp2/sp3 ratio on the formation process of conducting channels in diamond-like carbon films as a result of electrical breakdown was determined. Reproducible increase of diamond-like carbon film conductivity, with initial sp2/sp3 ratio larger than 0.16, was observed after electrical breakdown.

  17. Transmission photocathodes based on stainless steel mesh coated with deuterated diamond like carbon films

    NASA Astrophysics Data System (ADS)

    Huran, J.; Balalykin, N. I.; Feshchenko, A. A.; Kobzev, A. P.; Kleinová, A.; Sasinková, V.; Hrubčín, L.

    2014-07-01

    In this study we report on the dependence of electron emission properties on the transmission photocathodes DC gun based on stainless steel mesh coated with diamond like carbon films prepared at various technological conditions. Diamond like carbon films were deposited on the stainless steel mesh and silicon substrate by plasma enhanced chemical vapor deposition from gas mixtures CH4+D2+Ar, CH4+H2+Ar and reactive magnetron sputtering using a carbon target and gas mixtures Ar+D2, Ar+H2. The concentration of elements in films was determined by Rutherford backscattering spectrometry (RBS) and elastic recoil detection (ERD) analytical methods simultaneously. Chemical compositions were analyzed by Fourier transform infrared spectroscopy (FT-IR). Raman spectroscopy at visible excitation wavelength was used for the intensity ratio determination of Gaussian fit D-peak and G-peak of Raman spectra. The quantum efficiency was calculated from the measured laser energy and the measured cathode charge. The quantum efficiency of a prepared transmission photocathode was increased with increasing intensity ratio of D-peak and G-peak, which was increased by adding deuterium to the gas mixture and using technology reactive magnetron sputtering.

  18. Fluorinated diamond-like carbon as antithrombogenic coating for blood-contacting devices.

    PubMed

    Hasebe, Terumitsu; Shimada, Atsushi; Suzuki, Tetsuya; Matsuoka, Yoshiaki; Saito, Toshiya; Yohena, Satoshi; Kamijo, Aki; Shiraga, Nobuyuki; Higuchi, Mutsumi; Kimura, Kanako; Yoshimura, Hirokuni; Kuribayashi, Sachio

    2006-01-01

    Diamond-like carbon (DLC) is being considered for widespread clinical use as a surface coating for cardiovascular devices. We synthesized fluorinated DLC (F-DLC) coatings in order to create a more hydrophobic surface with improved antithrombogenicity and flexibility when compared with conventional DLC coatings by combining the inertness of DLC films with the advantage of fluorination. The purpose of this study was to evaluate the in vitro hemocompatibility and in vivo biocompatibility of the F-DLC coating for medical devices. The in vitro whole blood model confirmed that platelet loss was lower in the F-DLC group than in the noncoated group (SUS316L), which suggests the adhesion of a smaller number of platelets to F-DLC-coated materials. Furthermore, the biomarkers of mechanically induced platelet activation (beta-thromboglobulin) and activated coagulation (thrombin-antithrombin-three complex) were markedly reduced in the F-DLC-coated group. In vivo rat implant model studies revealed no excessive local and systemic inflammatory responses in the F-DLC group. The thickness of the fibrous tissue capsule surrounding the F-DLC-coated disk was almost equal to that of the noncoated SUS316L disk, which has the favorable biocompatibility for metallic implant materials. F-DLC coating thus appears to be a promising candidate for use as a coating material in blood-contacting devices.

  19. Does the Use of Diamond-Like Carbon Coating and Organophosphate Lubricant Additive Together Cause Excessive Tribochemical Material Removal?

    SciTech Connect

    Zhou, Yan; Leonard, Donovan N.; Meyer, Harry M.; Luo, Huimin; Qu, Jun

    2015-08-22

    We observe unexpected wear increase on a steel surface that rubbed against diamond-like carbon (DLC) coatings only when lubricated by phosphate-based antiwear additives. Contrary to the literature hypothesis of a competition between zinc dialkyldithiophosphate produced tribofilms and DLC-induced carbon transfer, here a new wear mechanism based on carbon-catalyzed tribochemical interactions supported by surface characterization is proposed

  20. Segment-Structured Diamond-Like Carbon Coatings on Polymer Catheter

    NASA Astrophysics Data System (ADS)

    Nakagawa, Taku; Ohishi, Ryusuke; Ohtake, Naoto; Takai, Osamu; Tsutsui, Nobumasa; Tsutsui, Yasuhiro; Muraki, Yasuhiro; Ogura, Jyunpei

    Diamond-like carbon (DLC) has remarkable mechanical and tribological properties. Besides those mechanical properties, it has been clarified that DLC shows high biocompatibility in recent years. DLC coating can give high strength, abrasion resistance, and biocompatibility for surface of substrates. Hence DLC is a candidate for the coating material for medical devices such as artificial organ, joint, catheter, etc. The objective of this study is to develop safety protection films for implantable medical polymer devices utilizing segment-structured DLC (S-DLC) coatings. S-DLC and continuous-structured DLC were deposited on polyurethane and nylon sheet for balloon catheters. As a result, friction coefficient of DLC coated polyurethane sheet was approximately one-sixth of that of pristine polyurethane sheet, and S-DLC showed very low friction coefficient of μ=0.1-0.15. DLC coating can prevent polyurethane sheet from worn out. The puncture-resistance of nylon sheets increased 0.2MPa on average by DLC coatings regardless of the film structure. It was confirmed that DLC inhibits adsorption of blood coagulation factor. In conclusion, we succeed to verify that these DLC films can improve tribological property, abrasion-resistance, puncture-resistance, and anti-thrombogenicity of polymer catheters. Moreover, segment-structured DLC films exhibits high performance for protection of polymer material for polymer catheters.

  1. Velocity dependence of coefficient of friction of diamond like carbon coatings

    NASA Astrophysics Data System (ADS)

    Sharma, Neha; Kumar, Niranjan; Dash, S.; Tyagi, A. K.

    2012-06-01

    The velocity dependence of coefficient of friction (CoF) of hydrogen-free and hydrogenated Diamond Like Carbon (DLC) coatings was studied on sliding. In low velocity regime, CoF of hydrogen-free DLC was found to increase which may be linked to a thermally activated pre-mature breaking of the surface asperities. However, CoF of hydrogenated DLC was found to decrease due to formation of graphite like lubricious layer and sustainability of cross-linked network of H-bonded atoms. In high velocity regime, CoF of hydrogen free DLC increases marginally due to an inefficient transfer of thermal energy while that of hydrogenated DLC increases due to rapid formation and rupture of atomic bonds.

  2. Surface properties and blood compatibility of commercially available diamond-like carbon coatings for cardiovascular devices.

    PubMed

    Fedel, Mariangela; Motta, Antonella; Maniglio, Devid; Migliaresi, Claudio

    2009-07-01

    The aim of this study was to determine the relationships between the surface properties and blood compatibility of in-use diamond-like carbon (DLC) coatings for cardiovascular components. Commercially available DLC films were characterized with respect to surface topography and wettability, protein adsorption from human plasma, and platelets adhesion/activation. Fibrinogen (Fng) and human serum albumin (HSA) adsorbed onto the sample surfaces were in particular quantified as two of the main proteins involved in blood compatibility. A low tendency of platelets to spread and form aggregates onto the DLC-coated surfaces has been described and related to a low Fng-to-HSA adsorption ratio. This study provides evidence that the rapid and tenacious binding of albumin molecules to DLC materials tends to passivate the surfaces and to inhibit Fng adsorption, thus imparting thromboresistance to the carbon coatings by rendering the surfaces less adhesive and activating for platelets. Albumin preferential adsorption was ascribed to high chemical heterogeneity of the DLC sample surfaces. The DLC films tested present a favorable behavior as regards blood compatibility with respect to platelet thrombus formation by reason of their surface properties.

  3. Gas barrier properties of diamond-like carbon films coated on PTFE

    NASA Astrophysics Data System (ADS)

    Ozeki, K.; Nagashima, I.; Ohgoe, Y.; Hirakuri, K. K.; Mukaibayashi, H.; Masuzawa, T.

    2009-05-01

    Diamond-like carbon (DLC) films were deposited on polytetrafluoroethylene (PTFE) using radio frequency (RF) plasma-enhanced chemical vapour deposition (PE-CVD). Before the DLC coating, the PTFE substrate was modified with a N 2 plasma pre-treatment to enhance the adhesive strength of the DLC to the substrate. The influences of the N 2 plasma pre-treatment and process pressure on the gas permeation properties of these DLC-coated PTFE samples were investigated. In the Raman spectra, the G peak position shifted to a lower wave number with increasing process pressure. With scanning electron microscopy (SEM), a network of microcracks was observed on the surface of the DLC film without N 2 plasma pre-treatment. The density of these cracks decreased with increasing process pressure. In the film subjected to a N 2 plasma pre-treatment, no cracks were observed at any process pressure. In the gas barrier test, the gas permeation decreased drastically with increasing film thickness and saturated at a thickness of 0.2 μm. The DLC-coated PTFE with the N 2 plasma pre-treatment exhibited a greater reduction in gas permeation than did the samples without pre-treatment. For both sample types, gas permeation decreased with increasing process pressure.

  4. Diamond-like carbon coatings for the protection of metallic artefacts: effect on the aesthetic appearance

    NASA Astrophysics Data System (ADS)

    Faraldi, Federica; Angelini, Emma; Caschera, Daniela; Mezzi, Alessio; Riccucci, Cristina; Caro, Tilde De

    2014-03-01

    Plasma-enhanced chemical vapour deposition (PECVD) is an environmentally friendly process used to deposit a variety of nano-structured coatings for the protection or the surface modification of metallic artefacts like the SiO2-like films that have been successfully tested on ancient silver, bronze and iron artefacts as barriers against aggressive agents. This paper deals with the preliminary results of a wider investigation aimed to the development of eco-sustainable coatings for the protection of Cu and Ag-based artefacts of archaeological and historic interest. Diamond-like carbon (DLC) coatings have been deposited by PECVD in different experimental conditions, in a capacitively coupled asymmetric plasma reactor, placing the substrates either on electrically powered electrode (cathodic mode) or grounded electrode (anodic mode) with and without hydrogen addition in the gas mixture. The final goal is to develop a coating with good protective effectiveness against aggressive atmospheres and contemporarily with negligible effects on the aesthetic appearance of the artefacts. The evaluation of possible colour changes of the surface patinas, due to coating process, was performed by optical microscopy and colorimetric measurements. Furthermore, to evaluate the reversibility of the thin DLC layer, an etching treatment in oxygen plasma has been successfully carried out and optimized. The chemical-physical characterization of the deposited DLC coatings was performed by means of the combined use of micro-Raman and XPS spectroscopies. The results show that the DLC films obtained in the anodic mode, may be proposed as a viable alternative to polymeric coatings for the protection of metallic ancient objects.

  5. Argonne News Brief: Self-Healing Diamond-Like Carbon Coating Could Revolutionize Lubrication

    SciTech Connect

    2016-08-01

    Argonne scientists discovered a technique to create a layer of diamond-like carbon on the surfaces between moving parts. This could change the future of lubrication—potentially making engines more efficient, more reliable, and even greener (by reducing heavy metal additives needed in engine oils.)

  6. Frictional and mechanical properties of diamond-like carbon-coated orthodontic brackets.

    PubMed

    Muguruma, Takeshi; Iijima, Masahiro; Brantley, William A; Nakagaki, Susumu; Endo, Kazuhiko; Mizoguchi, Itaru

    2013-04-01

    This study investigated the effects of a diamond-like carbon (DLC) coating on frictional and mechanical properties of orthodontic brackets. DLC films were deposited on stainless steel brackets using the plasma-based ion implantation/deposition (PBIID) method under two different atmospheric conditions. As-received metal brackets served as the control. Two sizes of stainless steel archwires, 0.018 inch diameter and 0.017 × 0.025 inch cross-section dimensions, were used for measuring static and kinetic friction by drawing the archwires through the bracket slots, using a mechanical testing machine (n = 10). The DLC-coated brackets were observed with a scanning electron microscope (SEM). Values of hardness and elastic modulus were obtained by nanoindentation testing (n = 10). Friction forces were compared by one-way analysis of variance and the Scheffé test. The hardness and elastic modulus of the brackets were compared using Kruskal-Wallis and Mann-Whitney U-tests. SEM photomicrographs showed DLC layers on the bracket surfaces with thickness of approximately 5-7 μm. DLC-coated brackets deposited under condition 2 showed significantly less static frictional force for the stainless steel wire with 0.017 × 0.025 inch cross-section dimensions than as-received brackets and DLC-coated brackets deposited under condition 1, although both DLC-coated brackets showed significantly less kinetic frictional force than as-received brackets. The hardness of the DLC layers was much higher than that of the as-received bracket surfaces. In conclusion, the surfaces of metal brackets can be successfully modified by the PBIID method to create a DLC layer, and the DLC-coating process significantly reduces frictional forces.

  7. Wear and Friction Characteristics of AlN/Diamond-Like Carbon Hybrid Coatings on Aluminum Alloy

    NASA Astrophysics Data System (ADS)

    Nakamura, Masashi; Kubota, Sadayuki; Suzuki, Hideto; Haraguchi, Tadao

    2015-10-01

    The use of diamond-like carbon (DLC) coatings has the potential to greatly improve the wear resistance and friction of aluminum alloys, but practical application has so far been limited by poor adhesion due to large difference in hardness and elasticity between the two materials. This study investigates the deposition of DLC onto an Al-alloy using an intermediate AlN layer with a graded hardness to create a hybrid coating. By controlling the hardness of the AlN film, it was found that the wear life of the DLC film could be improved 80-fold compared to a DLC film deposited directly onto Al-alloy. Furthermore, it was demonstrated through finite element simulation that creating a hardness gradient in the AlN intermediate layer reduces the distribution of stress in the DLC film, while also increasing the force of adhesion between the DLC and AlN layers. Given that both the DLC and AlN films were deposited using the same unbalanced magnetron sputtering method, this process is considered to represent a simple and effective means of improving the wear resistance of Al-alloy components commonly used within the aerospace and automotive industries.

  8. Dissolution effect and cytotoxicity of diamond-like carbon coatings on orthodontic archwires.

    PubMed

    Kobayashi, Shinya; Ohgoe, Yasuharu; Ozeki, Kazuhide; Hirakuri, Kenji; Aoki, Hideki

    2007-12-01

    Nickel-titanium (NiTi) has been used for implants in orthodontics due to the unique properties such as shape memory effect and superelasticity. However, NiTi alloys are eroded in the oral cavity because they are immersed by saliva with enzymolysis. Their reactions lead corrosion and nickel release into the body. The higher concentrations of Ni release may generate harmful reactions. Ni release causes allergenic, toxic and carcinogenic reactions. It is well known that diamond-like carbon (DLC) films have excellent properties, such as extreme hardness, low friction coefficients, high wear resistance. In addition, DLC film has many other superior properties as a protective coating for biomedical applications such as biocompatibility and chemical inertness. Therefore, DLC film has received enormous attention as a biocompatible coating. In this study, DLC film coated NiTi orthodontic archwires to protect Ni release into the oral cavity. Each wire was immersed in physiological saline at the temperature 37 degrees C for 6 months. The release concentration of Ni ions was detected using microwave induced plasma mass spectrometry (MIP-MS) with the resolution of ppb level. The toxic effect of Ni release was studied the cell growth using squamous carcinoma cells. These cells were seeded in 24 well culture plates and materials were immersed in each well directly. The concentration of Ni ions in the solutions had been reduced one-sixth by DLC films when compared with non-coated wire. This study indicated that DLC films have the protective effect of the diffusion and the non-cytotoxicity in corrosive environment.

  9. Flexible camphor diamond-like carbon coating on polyurethane to prevent Candida albicans biofilm growth.

    PubMed

    Santos, Thaisa B; Vieira, Angela A; Paula, Luciana O; Santos, Everton D; Radi, Polyana A; Khouri, Sônia; Maciel, Homero S; Pessoa, Rodrigo S; Vieira, Lucia

    2017-04-01

    Camphor was incorporated in diamond-like carbon (DLC) films to prevent the Candida albicans yeasts fouling on polyurethane substrates, which is a material commonly used for catheter manufacturing. The camphor:DLC and DLC film for this investigation was produced by plasma enhanced chemical vapor deposition (PECVD), using an apparatus based on the flash evaporation of organic liquid (hexane) containing diluted camphor for camphor:DLC and hexane/methane, mixture for DLC films. The film was deposited at a low temperature of less than 25°C. We obtained very adherent camphor:DLC and DLC films that accompanied the substrate flexibility without delamination. The adherence of camphor:DLC and DLC films on polyurethane segments were evaluated by scratching test and bending polyurethane segments at 180°. The polyurethane samples, with and without camphor:DLC and DLC films were characterized by Raman spectroscopy, scanning electron microscopy, atomic force microscopy, and optical profilometry. Candida albicans biofilm formation on polyurethane, with and without camphor:DLC and DLC, was assessed. The camphor:DLC and DLC films reduced the biofilm growth by 99.0% and 91.0% of Candida albicans, respectively, compared to bare polyurethane. These results open the doors to studies of functionalized DLC coatings with biofilm inhibition properties used in the production of catheters or other biomedical applications.

  10. Diamond-Like Carbon Coatings as Encapsulants for Photovoltaic Solar Cells

    SciTech Connect

    Pern, F. J.; Panosyan, Zh.; Gippius, A. A.; Kontsevoy, J. A.; Touryan, K.; Voskanyan, S.; Yengibaryan, Y.

    2005-02-01

    High-quality single-layer and bilayer diamond-like carbon (DLC) thin films are fabricated by two technologies, namely, ion-assisted plasma-enhanced deposition (IAPED) and electron cyclotron resonance (ECR) deposition. Deposition on various substrates, such as sapphires and solar cells, has been performed at low substrate temperatures (50 {approx} 80 C). The two deposition technologies allow good control over the growth conditions to produce DLC films with desired optical properties, thickness, and energy bandgap. The bilayer-structured DLC can be fabricated by using IAPED for the bottom layer followed by ECR for the top layer, or just by IAPED for both layers with different compositions. The DLC films have shown good spatial uniformity, density, microhardness, and adhesion strength. They exhibit excellent stability against attack by strong acids, prolonged damp-heat exposure at 85 C and 85% relative humidity, mechanical scratch, ultrasonication, and irradiation by ultraviolet (UV), protons, and electrons. When deposited on crystalline Si and GaAs solar cells in single-layer and/or bilayer structure, the DLC films not only serve as antireflection coating and protective encapsulant, but also improve the cell efficiencies.

  11. Development of a radio frequency atmospheric pressure plasma jet for diamond-like carbon coatings on stainless steel substrates

    NASA Astrophysics Data System (ADS)

    Sohbatzadeh, F.; Samadi, O.; Siadati, S. N.; Etaati, G. R.; Asadi, E.; Safari, R.

    2016-10-01

    In this paper, an atmospheric pressure plasma jet with capacitively coupled radio frequency discharge was developed for diamond-like carbon (DLC) coatings on stainless steel substrates. The plasma jet was generated by argon-methane mixture and its physical parameters were investigated. Relation between the plasma jet length and width of the powered electrode was discussed. Optical and electrical characteristics were studied by optical emission spectroscopy, voltage and current probes, respectively. The evolutions of various species like ArI, C2 and CH along the jet axis were investigated. Electron temperature and density were estimated by Boltzmann plot method and Saha-Boltzmann equation, respectively. Finally, a diamond-like carbon coating was deposited on stainless steel-304 substrates by the atmospheric pressure radio frequency plasma jet in ambient air. Raman spectroscopy, scanning electron microscopy (SEM), atomic force microscopy and Vickers hardness test were used to study the deposited films. The length of the jet was increased by increasing the width of the powered electrode. The estimated electron temperature and density were 1.43 eV and 1.39 × 1015 cm-3, respectively. Averaged Vicker's hardness of the coated sample was three times greater than that of the substrate. The SEM images of the deposited thin films revealed a 4.5 μm DLC coated for 20 min.

  12. Reduction in static friction by deposition of a homogeneous diamond-like carbon (DLC) coating on orthodontic brackets.

    PubMed

    Akaike, Shun; Hayakawa, Tohru; Kobayashi, Daishiro; Aono, Yuko; Hirata, Atsushi; Hiratsuka, Masanori; Nakamura, Yoshiki

    2015-01-01

    In orthodontics, a reduction in static friction between the brackets and wire is important to enable easy tooth movement. The aim of this study was to examine the effects of a homogeneous diamond-like carbon (DLC) coating on the whole surfaces of slots in stainless steel orthodontic brackets on reducing the static friction between the brackets and the wire. The DLC coating was characterized using Raman spectroscopy, surface roughness and contact angle measurements, and SEM observations. Rectangular stainless steel and titanium-molybdenum alloy wires with two different sizes were employed, and the static friction between the brackets and wire was measured under dry and wet conditions. The DLC coating had a thickness of approximately 1.0 μm and an amorphous structure was identified. The results indicated that the DLC coating always led to a reduction in static friction.

  13. Optimum Me-DLC coatings and hard coatings for tribological performance[Diamond-Like Carbon

    SciTech Connect

    Su, Y.L.; Kao, W.H.

    2000-02-01

    In this study, hard coatings (TiN, TiCN, CrN, and CrCN) and Me-DLC coatings (Ti{sub x%}-C:H and Cr{sub x%}-C:H) were deposited on tungsten carbide (WC) substrate by multiarc physical vapor deposition (MAPVD) and unbalanced magnetron (UBM) sputtering, respectively. Counterbodies of the AISI 1045 steel cylinder and the AA7075T65l aluminum cylinder were used in the cylinder-on-disk, line-contact wear mode under dry condition; a counterbody of the AISI 51200 steel ball was used in the ball-on-disk, point-contact wear mode, under both dry and lubricated conditions. All wear tests were conducted with a reciprocating machine. After the tests, the most suitable coating for various counterbodies and test environments was selected. For the coating/1045 steel cylinder, the Ti{sub 10%}-C:H coating possesses excellent tribological characteristics. For the coating/7075T651 aluminum cylinder, hard coatings display excellent wear resistance. For the coating/steel ball, CrCN and CrN coatings display very little wear under both dry and lubricated conditions. On TiN and TiCN coatings, special wear mechanisms of material transfer, adhesion wear, and fatigue fracture occurred during initial tests under kerosene lubrication.

  14. Further improvement of mechanical and tribological properties of Cr-doped diamond-like carbon nanocomposite coatings by N codoping

    NASA Astrophysics Data System (ADS)

    Zou, Changwei; Xie, Wei; Tang, Xiaoshan

    2016-11-01

    In this study, the effects of nitrogen codoping on the microstructure and mechanical properties of Cr-doped diamond-like carbon (DLC) nanocomposite coatings were investigated in detail. Compared with undoped DLC coatings, the Cr-DLC and N/Cr-DLC coatings showed higher root-mean-square (RMS) roughness values. However, from the X-ray photoelectron spectroscopy (XPS) and Raman results, the fraction of sp2 carbon bonds of N/Cr-DLC coatings increased with increasing N content, which indicated the graphitization of the coatings. The hardness and elastic modulus of N/Cr-DLC coatings with 1.8 at. % N were about 26.8 and 218 GPa, respectively. The observed hardness increase with N codoping was attributed to the incorporation of N in the C network along with the formation of CrC(N) nanoparticles, as confirmed from the transmission electron microscopy (TEM) results. The internal stress markedly decreased from 0.93 to 0.32 GPa as the N content increased from 0 to 10.3 at. %. Furthermore, N doping significantly improved the high-temperature dry friction behavior of DLC coatings. The friction coefficient of N/Cr-DLC coatings with 8.0 and 10.3 at. % N was kept at about 0.2 during the overall sliding test at 500 °C. These results showed that appropriate N doping could promote the mechanical and tribological properties of Cr-DLC nanocomposite coatings.

  15. Ultra hydrophobic/superhydrophilic modified cotton textiles through functionalized diamond-like carbon coatings for self-cleaning applications.

    PubMed

    Caschera, Daniela; Cortese, Barbara; Mezzi, Alessio; Brucale, Marco; Ingo, Gabriel Maria; Gigli, Giuseppe; Padeletti, Giuseppina

    2013-02-26

    A stable and improved control of the wettability of textiles was obtained by using a coating of diamond like carbon (DLC) films on cotton by PECVD. By controlling different plasma pretreatments of argon, oxygen, and hydrogen on the cotton fibers' surface, we have shown that the pretreatments had a significant impact on wettability behavior resulting from an induced nanoscale roughness combined with an incorporation of selected functional groups. Upon subsequent deposition of diamond like carbon (DLC) films, the cotton fibers yield to a highly controlled chemical stability and hydrophobic state and could be used for self-cleaning applications. By controlling the nature of the plasma pretreatment we have shown that the oxygen plasma pretreatment was more effective than the argon and hydrogen for the superhydrophilic/ultra hydrophobic properties. The chemical and morphological changes of the cotton fibers under different treatments were characterized using X-ray photoelectron and Raman spectroscopy, AFM, and water contact angle measurements. The mechanism underlying the water-repellent properties of the cotton fibers provides a new and innovative pathway into the development of a range of advanced self-cleaning textiles.

  16. Influence of load on the dry frictional performance of alkyl acrylate copolymer elastomers coated with diamond-like carbon films

    NASA Astrophysics Data System (ADS)

    Martínez Martínez, D.; Nohava, Jiri; De Hosson, J. Th. M.

    2015-11-01

    In this work, the influence of applied load on the frictional behavior of alkyl acrylate copolymer elastomers coated with diamond-like carbon films is studied at dry conditions. The performance of two coatings with very different microstructure (patched vs. continuous film) is compared with the uncoated substrate. A wide range of applied loads is explored, from 1 mN to 1 N, which is achieved by using a specific tribometer. The variation of 3 orders of magnitude in the applied load leads to a strong variation of the observed frictional phenomena. The different behavior of both samples at various loads is explained using a model that considers two contributions to the friction coefficient, namely, an adhesive and a rubber hysteresis part. The constraints and applicability of such model are critically evaluated.

  17. Adhesion of slime producing Staphylococcus epidermidis strains to PVC and diamond-like carbon/silver/fluorinated coatings.

    PubMed

    Katsikogianni, M; Spiliopoulou, I; Dowling, D P; Missirlis, Y F

    2006-08-01

    Staphylococcus epidermidis has emerged as a pathogen associated with infections of implanted medical devices. Bacterial adhesion is a crucial step in infection on biomaterial surfaces. To quantitatively determine the relationship between poly (vinyl chloride) (PVC) surface properties and bacterial adhesion, we have compared attachment of slime-producing S. epidermidis strains on PVC and various coatings under flow conditions. Bacterial adhesion and colonization was quantified by counting the viable organisms on the adherent surface as well as by scanning electron microscopy, epifluorescence microscopy and atomic force microscopy. Fluorination of the PVC surface encourages S. epidermidis adhesion whereas; diamond-like carbon (DLC) and especially silver (Ag) coatings seem to inhibit its adhesion. In most materials, the number of adherent bacteria decreased with the increase of shear rate. These results indicate that bacterial adhesion is influenced by the chemical properties of the polymeric surfaces, the surface roughness and the associated flow conditions.

  18. The Improvement of Tribological and Fatigue Properties of Casting Magnesium Alloy AZ91 Performed Diamond Like Carbon Coating

    NASA Astrophysics Data System (ADS)

    Akebono, Hiroyuki; Suzuki, Hideto

    In recent years, magnesium alloy has been widely used because of its low weight and ease of recycling. However, because magnesium alloys provide inferior wear resistance, it is necessary to improve this property to use magnesium alloy for more machine parts. For this study, we produced a diamond like carbon (DLC) coating that has high hardness, low friction, and excellent wear resistance. With DLC coated onto a soft material such as magnesium alloy, the adhesion strength between the substrate and the coating poses an important problem. Therefore, in this study, to acquire high adhesion strength, the DLC coating process was performed using unbalanced magnetron sputtering (UBMS). A tungsten-doped inter-layer was formed on the substrate. Onto the inter-layer, nano-order DLC coatings of two kinds were laminated. Wear tests and fatigue tests were carried out. The DLC-coated magnesium alloy exhibited excellent wear friction. Furthermore, DLC coatings raised its fatigue reliability over that of the substrate alone.

  19. Interlayer formation of diamond-like carbon coatings on industrial polyethylene: Thickness dependent surface characterization by SEM, AFM and NEXAFS

    NASA Astrophysics Data System (ADS)

    Fischer, Christian B.; Rohrbeck, Magdalena; Wehner, Stefan; Richter, Matthias; Schmeißer, Dieter

    2013-04-01

    The coating of materials with diamond-like carbon (DLC) is a very common way to change and improve their basic characteristics. Although DLC is used on several substrates, the chemical and physical properties throughout the coating process on plastics are yet sparsely investigated. Two types of protective coatings one sp3-enriched (robust, r-type) and one with more sp2-centers (flexible, f-type) have been realized on polyethylene by PECVD deposition. SEM and AFM analysis of coated samples of DLC types revealed diverse surface topographies on different scales and images appeared even differently smoothed by the carbonaceous deposits. Grains of both DLC types are platelet-shaped and nearly double in size for the robust type indicating fundamental differences in the epitaxial DLC growth. NEXAFS spectroscopy showed significant details of carbon centers in chemically different neighborhood displaying a characteristic fingerprint behavior. Comparison of deposition models revealed a mechanism of interlayer formation which is discussed in detail. Interlayer formation is clearly the appropriate explanation of the process for the current carbon deposition between these two unequal materials. An improved understanding of hard DLC and soft polyethylene assembly is given in the presented work.

  20. Friction and wear performance of bearing ball sliding against diamond-like carbon coatings

    NASA Astrophysics Data System (ADS)

    Wu, Shenjiang; Kousaka, Hiroyuki; Kar, Satyananda; Li, Dangjuan; Su, Junhong

    2017-01-01

    We have studied the tribological properties of bearing steel ball (Japan standard, SUJ2) sliding against tetrahedral amorphous carbon (ta-C) coatings and amorphous hydrogenated carbon (a-C:H) coatings. The reciprocating sliding testes are performed with ball-on-plate friction tester in ambient air condition. Analysis of friction coefficient, wear volume and microstructure in wear scar are carried out using optical microscopy, atom force morphology (AFM) and Raman spectroscopy. The results show the SUJ2 on ta-C coating has low friction coefficient (around 0.15) but high wear loss. In contrast, the low wear loss of SUJ2 on a-C:H coating with high (around 0.4) and unsteady friction coefficient. Some Fe2O3, FeO and graphitization have been found on the wear scar of SUJ2 sliding against ta-C coating. Nearly no oxide materials exist on the wear scar of SUJ2 against a-C:H coating. The mechanism and hypothesis of the wear behavior have been investigated according to the measurement results. This study will contribute to proper selection and understand the tribological performance of bearing steels against DLC coatings.

  1. Diamond-like carbon coatings for orthopedic applications: Tribological behaviors of vacuum arc diamond-like carbon-coated titanium alloy against medical-grade ultra-high molecular weight polyethylene

    NASA Astrophysics Data System (ADS)

    Xu, Tianzong

    An extensive and detailed investigation of tribological behaviors of vacuum arc carbon coated Ti6Al4V against medical grade ultra high molecular weight polyethylene were conducted in this work in order to investigate the potential use of diamond-like carbon coatings for orthopedic applications. Further, the gas plasma sterilization and surface modification technique were evaluated as an alternative to the currently used gamma-radiation technique which has previously shown degradation effects on the mechanical properties of the UHMWPE. In addition, an emerging polymer surface modification technique using high-energy ion-implantation is explored to modify the surface of the UHMWPE for improved wear performance. The experiments were performed using a standard pin-on-disk wear tester under both dry and distilled water lubricated condition. The evolution of friction and wear processes are interpreted in the context of in situ recorded coefficient of friction and microscopic images of worn surfaces. Sliding wear tests demonstrated the existence of two distinct friction and wear regimes which comprise physically different dominant mechanisms: an adhesive and abrasive mechanism activated early in the run-in stage, followed by fatigue processes which developed later microscopically in the (quasi) steady-state sliding stage. The effects of surface roughness, distilled water lubricant, coating structure, polymer sterilization and surface modification on the tribological behaviors are presented and discussed in light of these results. Explanations based on theories of sliding contact stress fields, temperature profiles, as well as lubrication and coating fracture mechanics are presented to discuss and support the experimental results. It is revealed that, largely depending on material structures and surface roughness of both articulating components, significantly improved friction and wear performance can be achieved by optimal design of their process

  2. Tribological investigation of diamond-like carbon coated micro-dimpled surface under bovine serum and osteoarthritis oriented synovial fluid

    PubMed Central

    Ghosh, Subir; Choudhury, Dipankar; Roy, Taposh; Bin Mamat, Azuddin; Masjuki, H H; Pingguan-Murphy, Belinda

    2015-01-01

    Osteoarthritis-oriented synovial fluid (OASF), i.e., that typical of a patient with osteoarthritis, has different physical and biological characteristics than bovine serum (BS), a lubricant widely used in biotribological investigations. Micro-dimpled and diamond-like carbon- (DLC) coated surfaces are key emerging interfaces for orthopedic implants. In this study, tribological performances of dimpled surfaces, with and without DLC coating, have been investigated under both BS and OASF. The friction tests were performed utilizing a pin on a disk tribometer, whereas contact pressure, speed, and temperature were simulated to a ‘medium walking gait’ of hip joint conditions. The mechanical properties of the specimen and the physical properties of the lubricant were characterized before the friction test. Raman analysis was conducted to identify the coating condition both before and after the test. The DLC-coated dimpled surface showed maximum hardness and residual stress. A DLC-coated dimpled surface under an OASF lubricated condition yielded a lower friction coefficient and wear compared to those of plain and dimpled specimens. The higher graphitization of coated materials with increasing load was confirmed by Raman spectroscopy. PMID:27877803

  3. Tribological investigation of diamond-like carbon coated micro-dimpled surface under bovine serum and osteoarthritis oriented synovial fluid

    NASA Astrophysics Data System (ADS)

    Ghosh, Subir; Choudhury, Dipankar; Roy, Taposh; Mamat, Azuddin Bin; Masjuki, H. H.; Pingguan-Murphy, Belinda

    2015-06-01

    Osteoarthritis-oriented synovial fluid (OASF), i.e., that typical of a patient with osteoarthritis, has different physical and biological characteristics than bovine serum (BS), a lubricant widely used in biotribological investigations. Micro-dimpled and diamond-like carbon- (DLC) coated surfaces are key emerging interfaces for orthopedic implants. In this study, tribological performances of dimpled surfaces, with and without DLC coating, have been investigated under both BS and OASF. The friction tests were performed utilizing a pin on a disk tribometer, whereas contact pressure, speed, and temperature were simulated to a ‘medium walking gait’ of hip joint conditions. The mechanical properties of the specimen and the physical properties of the lubricant were characterized before the friction test. Raman analysis was conducted to identify the coating condition both before and after the test. The DLC-coated dimpled surface showed maximum hardness and residual stress. A DLC-coated dimpled surface under an OASF lubricated condition yielded a lower friction coefficient and wear compared to those of plain and dimpled specimens. The higher graphitization of coated materials with increasing load was confirmed by Raman spectroscopy.

  4. Diamond-like carbon coatings enhance the hardness and resilience of bearing surfaces for use in joint arthroplasty.

    PubMed

    Roy, M E; Whiteside, L A; Xu, J; Katerberg, B J

    2010-04-01

    The purpose of this study was to evaluate the potential of a hard diamond-like carbon (DLC) coating to enhance the hardness and resilience of a bearing surface in joint replacement. The greater hardness of a magnesium-stabilized zirconium (Mg-PSZ) substrate was expected to provide a harder coating-substrate composite microhardness than the cobalt-chromium alloy (CoCr) also used in arthroplasty. Three femoral heads of each type (CoCr, Mg-PSZ, DLC-CoCr and DLC-Mg-PSZ) were examined. Baseline (non-coated) and composite coating/substrate hardness was measured by Vickers microhardness tests, while nanoindentation tests measured the hardness and elastic modulus of the DLC coating independent of the Mg-PSZ and CoCr substrates. Non-coated Mg-PSZ heads were considerably harder than non-coated CoCr heads, while DLC coating greatly increased the microhardness of the CoCr and Mg-PSZ substrates. On the nanoscale the non-coated heads were much harder than on the microscale, with CoCr exhibiting twice as much plastic deformation as Mg-PSZ. The mechanical properties of the DLC coatings were not significantly different for both the CoCr and Mg-PSZ substrates, producing similar moduli of resilience and plastic resistance ratios. DLC coatings greatly increased hardness on both the micro and nano levels and significantly improved resilience and resistance to plastic deformation compared with non-coated heads. Because Mg-PSZ allows less plastic deformation than CoCr and provides a greater composite microhardness, DLC-Mg-PSZ will likely be more durable for use as a bearing surface in vivo.

  5. Ultrathin diamond-like carbon coatings used for reduction of pole tip recession in magnetic tape heads

    NASA Astrophysics Data System (ADS)

    Scott, William W.; Bhushan, Bharat; Lakshmikumaran, Anand V.

    2000-05-01

    Diamond-like carbon (DLC) coatings were deposited using a commercial direct ion beam deposition technique on thin-film Al2O3-TiC inductive write heads. The coating thicknesses used were 5, 10, and 20 nm. Accelerated wear tests were conducted with metal particle tapes in a linear tape drive. Atomic force microscopy was used to image the thin-film regions to measure pole tip recession (PTR), relative wear of the pole tip with respect to the air bearing surface. It is found that the coating wears off of the head substrate to a significant extent in the first 1000 km of sliding distance. The coating is worn off the substrate long before it wears off of the thin-film region. The existence of the coating on the thin-film region provides close enough wear characteristics between the substrate and thin film that the two wear at similar rates. This results in little growth in pole tip recession. Early in the wear test, the coated substrate wears at a slightly higher rate than the DLC coated thin-film region due to the difference in tape contact pressure between the two materials; decreasing PTR is the result. As the coating on the substrate wears significantly, PTR begins to increase with sliding distance. Failure does not actually occur until the coating has worn off of the thin-film region. Near failure, the coating delaminates locally. Results indicate that coatings of 20 nm thickness may provide protection against PTR in future tape drives.

  6. Human umbilical vein endothelial cell interaction with phospholipid polymer nanofibers coated by micro-patterned diamond-like carbon (DLC)

    NASA Astrophysics Data System (ADS)

    Yoshida, Soki; Hasebe, Terumitsu; Suzuki, Tetsuya; Hotta, Atsushi

    2013-03-01

    Blood-contacting medical devices should possess the surface properties with the following two important characteristics: The first is the anti-thrombogenicity of the material surface and the second is the re-endothelialization over the device surface after long-term implantation, because endothelial cells have excellent anticoagulant properties in blood vessels. To develop highly hemocompatible materials that could promote surface endothelialization, we investigated biocompatible polymers coated with thin diamond-like carbon (DLC) film. In this research, we examined the viability of human umbilical vein endothelial cells (HUVECs) for hydrophilic 2-methacryloyloxyethyl phosphorylcholine (MPC) fibers with DLC coatings, both of which were known to be anti-thrombogenic. DLC was synthesized on MPC by varying the ratio of covered area by patterned DLC. HUVECs were seeded on DLC-coated MPC for 6 days. The results indicated that the MPC surface with DLC did not disturb HUVEC proliferation in 6 days of culture. Additionally, we are currently making strong efforts to fabricate MPC fibers with bFGF which is an important growth factor involved in cell proliferation. MPC containing bFGF with DLC coatings could be extensively utilized for blood-contacting medical devices.

  7. Tribological behaviors of diamond-like carbon coatings on plasma nitrided steel using three BN-containing lubricants

    NASA Astrophysics Data System (ADS)

    Jia, Zheng-feng; Wang, Peng; Xia, Yan-qiu; Zhang, Hao-bo; Pang, Xian-juan; Li, Bin

    2009-04-01

    In this work, diamond-like carbon (DLC) coatings were deposited on plasma nitrided AISI 1045 steel by magnetron sputtering. Three BN-containing additives and molybdenum dithiocarbamate (MoDTC) were added to poly-alpha-olefin (PAO) as additives. The additive content (mass fraction) in PAO was fixed at 0.5 wt%. The friction and wear characters of DLC coatings on nitrided steel discs sliding against AISI 52100 steel balls were tested under the lubricated conditions. It was found that borate esters have a higher load carrying capacity and much better anti-wear and friction-reducing ability than that of MoDTC. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were employed to explore the properties of the worn surface and the mechanism of friction and wear. According to the XPS analysis, the adsorbed organic N-containing compounds and BN are, possibly, the primary reason for the novel borate esters to possess a relatively constant coefficient of friction and lower wear rate. On the other hand, possibly, the MoDTC molecules break down during sliding and produce many Mo-oxides, and then the Mo-oxides destroy the DLC coating because of its sharp edge crystalline solid structure. After destroying the DLC coating, the MoDTC react with metals and form MoS 2 tribofilm, and decrease coefficient of friction of rubbing pairs.

  8. Self-Lubricating-Diamond Like Coatings Deposition

    DTIC Science & Technology

    1989-12-01

    LABORATORY WRIGHT RESEARCH AND DEVELOPMENT CENTER AIR FORCE SYSTEMS COMMAND WRIGHT-PATTERSON AIR FORCE BASE, OH 45433-6533 1 ~ is NOTICE When...demand for diamond-like coatings of boron nitride (BN) in a large number of tribological applications including cryogenic bearings and adiabatic engines...neutralizer filaments; a new grid system for the ion source; and mounting jigs and hardware for rotating (planetary-type) depositions. All of these

  9. Wear resistance of thick diamond like carbon coatings against polymeric materials used in single screw plasticizing technology

    NASA Astrophysics Data System (ADS)

    Zitzenbacher, G.; Liu, K.; Forsich, C.; Heim, D.

    2015-05-01

    Wear on the screw and barrel surface accompany polymer single screw plasticizing technology from the beginning. In general, wear on screws can be reduced by using nitrided steel surfaces, fused armour alloys on the screw flights and coatings. However, DLC-coatings (Diamond Like Carbon) comprise a number of interesting properties such as a high hardness, a low coefficient of friction and an excellent corrosion resistance due to their amorphous structure. The wear resistance of about 50 µm thick DLC-coatings against polyamide 6.6, polybutylene terephthalate and polypropylene is investigated in this paper. The tribology in the solids conveying zone of a single screw extruder until the beginning of melting is evaluated using a pin on disc tribometer and a so called screw tribometer. The polymeric pins are pressed against coated metal samples using the pin on disc tribometer and the tests are carried out at a defined normal force and sliding velocity. The screw tribometer is used to perform tribological experiments between polymer pellets and rotating coated metal shafts simulating the extruder screw. Long term experiments were performed to evaluate the wear resistance of the DLC-coating. A reduction of the coefficient of friction can be observed after a frictional distance of about 20 kilometers using glass fibre reinforced polymeric materials. This reduction is independent on the polymer and accompanied by a black layer on the wear surface of the polymeric pins. The DLC-coated metal samples show an up to 16 µm deep wear track after the 100 kilometer test period against the glass fiber filled materials only.

  10. Controlling the drug release rate from electrospun phospholipid polymer nanofibers with micro-patterned diamond-like carbon (DLC) coating

    NASA Astrophysics Data System (ADS)

    Yoshida, Soki; Hasebe, Terumitsu; Suzuki, Tetsuya; Hotta, Atsushi

    2013-03-01

    An effective way of controlling drug release from polymer fibers coated with thin diamond-like carbon (DLC) film was introduced. It is highly expected that electrospinning will produce polymer fiber and useful for drug delivery systems. The drug release rate should be rather precisely controlled in order to prevent side effects due to the burst drug-release from polymers. Our previous research has already revealed that the micro-patterned DLC could control the drug release rate from biocompatible polymer films. In this study, the drug release profile of the polymer fibers with DLC was investigated. Hydrophilic 2-methacryloyloxyethyl phosphorylcholine (MPC) was selected as a typical biocompatible polymer. It is well known that the MPC polymers show good hemocompatibility and that both MPC and DLC are excellent biocompatible materials with antithrombogenicity. The DLC/MPC composites could therefore be extensively utilized for blood-contacting medical devices. The percentile covered area with patterned DLC on MPC fibers containing drug was varied from 0% (without DLC) to 100% (fully covered). It was found that the drug eluting profiles could be effectively controlled by changing the covered area of micro-patterned DLC coatings on MPC.

  11. On the performances and wear of WC-diamond like carbon coated tools in drilling of CFRP/Titanium stacks

    NASA Astrophysics Data System (ADS)

    Boccarusso, L.; Durante, M.; Impero, F.; Minutolo, F. Memola Capece; Scherillo, F.; Squillace, A.

    2016-10-01

    The use of hybrid structures made of CFRP and titanium alloys is growing more and more in the last years in the aerospace industry due to the high strength to weight ratio. Because of their very different characteristics, the mechanical fastening represent the most effective joining technique for these materials. As a consequence, drilling process plays a key role in the assembly. The one shot drilling, i.e. the contemporary drilling of the stack of the two materials, seems to be the best option both in terms of time saving and assembly accuracy. Nevertheless, due to the considerable different machinability of fiber reinforced plastics and metallic materials, the one shot drilling is a critical process both for the holes quality and for the tools wear. This research was carried out to study the effectiveness of new generation tools in the drilling of CFRP/Titanium stacks. The tools are made of sintered grains of tungsten carbide (WC) in a binder of cobalt and coated with Diamond like carbon (DLC), and are characterized by a patented geometry; they mainly differ in parent WC grain size and binder percentage. Both the cutting forces and the wear phenomena were accurately investigated and the results were analyzed as a function of number of holes and their quality. The results show a clear increase of the cutting forces with the number of holes for all the used drilling tools. Moreover, abrasive wear phenomena that affect initially the tools coating layer were observed.

  12. In vitro comparison of the hemocompatibility of diamond-like carbon and carbon nitride coatings with different atomic percentages of N.

    PubMed

    Zhao, Mengli; Li, Dejun; Zhang, Yiteng; Guo, Meixian; Deng, Xiangyun; Gu, Hanqing; Wan, Rongxin

    2012-04-01

    Carbon nitride (CN( x )) and diamond-like carbon (DLC) coatings were prepared by dc magnetron sputtering at room temperature. Different partial pressures of N(2) were used to synthesize CN( x ) to evaluate the relationship between the atomic percentage of nitrogen and hemocompatibility. Auger electron spectroscopy and atomic force microscopy indicated atomic percentages of N of 0.12 and 0.22 and that the CN( x ) coatings were smooth. An in vitro study of the hemocompatibility of the coatings revealed that both CN( x ) coatings had better anticoagulant properties and lower platelet adhesion than DLC. Compared with CN(0.12), the CN(0.22) coating showed longer dynamic clotting time (about 42 min), static clotting time (23.6 min) and recalcification time (45.6 s), as well as lower platelet adhesion (102 cells μm(-2)), aggregation, and activation. The presence of nitrogen in the CN( x ) coatings induced their enhanced hemocompatibility compared with DLC.

  13. Surface grafting of blood compatible zwitterionic poly(ethylene glycol) on diamond-like carbon-coated stent.

    PubMed

    Lee, Bong Soo; Shin, Hong-Sub; Park, Kwideok; Han, Dong Keun

    2011-03-01

    Blood compatibility is the most important aspect for blood-contacting medical devices including cardiovascular stents. In this study, the surface of nickel-titanium (TiNi) stent was coated with diamond-like carbon (DLC) and then subsequently grafted by using zwitterion (N(+) and SO(3) (-))-linked poly(ethylene glycol) (PEG). We hypothesize that this coupling of zwitterion and PEG may significantly improve blood compatibility of DLC-coated TiNi stent. The surface modified TiNi stents, including PEG-grafted stent (DLC-PEG) and zwitterionic PEG-grafted one (DLC-PEG-N-S) were the main focus on the tests of surface characteristics and blood compatibility. The zwitterionic PEG derivatives were obtained from a series of chemical reactions at room temperature. The results exhibited that as compared to the DLC-PEG, the hydrophilicity was much better with DLC-PEG-N-S and significantly increased atomic percentage of oxygen and nitrogen proved the entity of zwitterions on the surface of DLC-PEG-N-S. Meanwhile, the adsorption of blood proteins such as, human serum albumin (HSA) and fibrinogen was found considerably down-regulated in DLC-PEG-N-S, due mainly to the protein-repellent effect of PEG and zwitterion. Microscopic observation also revealed that as compared with the other substrates without zwitterion, the degree of platelet adhesion was the lowest with DLC-PEG-N-S. In addition, DLC-PEG-N-S retained an extended blood coagulation time as measured by activated partial thromboplastin time (APTT). The present results suggested that surface grafting of zwitterionic PEG derivatives could substantially enhance the blood compatibility of TiNi-DLC stent. In conclusion, anti-fouling properties of PEG and zwitterions are expected to be very useful in advancing overall stent performance.

  14. Low Friction Property of Diamond-Like Carbon Coating Films and Oxygen Transmission Ratio of Amorphous Carbon Films Deposited by Advanced Coating Processes

    NASA Astrophysics Data System (ADS)

    Watanabe, Toshiyuki; Kano, Makoto; Yoshida, Kentaro; Suzuki, Tetsuya

    2012-09-01

    The topics of the applied technology of amorphous carbon film to reduce friction using diamond-like carbon (DLC) coated by the vacuum arc ion plating process and to improve the gas barrier property using the amorphous carbon film by the atmospheric pressure plasma process are introduced with the basic experimental results. For reducing friction, the super low friction coefficient below 0.01 has been found when the tetrahedral amorphous carbon coating deposited by T-shape filtered arc deposition method [ta-C(T)] was evaluated the friction property under oleic acid lubrication at pure sliding condition. It was thought that the low share strength tribofilm composed of water and oleic acid mono-layer seemed to be formed on the sliding interface. For gas barrier performance, the amorphous carbon film deposited by the atmospheric pressure plasma chemical vapour deposition (CVD) technique on poly(ethylene terephthalate) (PET) substrate was improved the oxygen transmission ratio (OTR) around 30% compared with that of uncoated PET substrate. These advanced performance obtained by the optimum material combination of DLC with lubricant and the original atmospheric pressure plasma CVD technique are expected to be applied on the actual application for the different types of the industrial fields in near future.

  15. A novel radial anode layer ion source for inner wall pipe coating and materials modification—Hydrogenated diamond-like carbon coatings from butane gas

    NASA Astrophysics Data System (ADS)

    Murmu, Peter P.; Markwitz, Andreas; Suschke, Konrad; Futter, John

    2014-08-01

    We report a new ion source development for inner wall pipe coating and materials modification. The ion source deposits coatings simultaneously in a 360° radial geometry and can be used to coat inner walls of pipelines by simply moving the ion source in the pipe. Rotating parts are not required, making the source ideal for rough environments and minimizing maintenance and replacements of parts. First results are reported for diamond-like carbon (DLC) coatings on Si and stainless steel substrates deposited using a novel 360° ion source design. The ion source operates with permanent magnets and uses a single power supply for the anode voltage and ion acceleration up to 10 kV. Butane (C4H10) gas is used to coat the inner wall of pipes with smooth and homogeneous DLC coatings with thicknesses up to 5 μm in a short time using a deposition rate of 70 ± 10 nm min-1. Rutherford backscattering spectrometry results showed that DLC coatings contain hydrogen up to 30 ± 3% indicating deposition of hydrogenated DLC (a-C:H) coatings. Coatings with good adhesion are achieved when using a multiple energy implantation regime. Raman spectroscopy results suggest slightly larger disordered DLC layers when using low ion energy, indicating higher sp3 bonds in DLC coatings. The results show that commercially interesting coatings can be achieved in short time.

  16. A novel radial anode layer ion source for inner wall pipe coating and materials modification--hydrogenated diamond-like carbon coatings from butane gas.

    PubMed

    Murmu, Peter P; Markwitz, Andreas; Suschke, Konrad; Futter, John

    2014-08-01

    We report a new ion source development for inner wall pipe coating and materials modification. The ion source deposits coatings simultaneously in a 360° radial geometry and can be used to coat inner walls of pipelines by simply moving the ion source in the pipe. Rotating parts are not required, making the source ideal for rough environments and minimizing maintenance and replacements of parts. First results are reported for diamond-like carbon (DLC) coatings on Si and stainless steel substrates deposited using a novel 360° ion source design. The ion source operates with permanent magnets and uses a single power supply for the anode voltage and ion acceleration up to 10 kV. Butane (C4H10) gas is used to coat the inner wall of pipes with smooth and homogeneous DLC coatings with thicknesses up to 5 μm in a short time using a deposition rate of 70 ± 10 nm min(-1). Rutherford backscattering spectrometry results showed that DLC coatings contain hydrogen up to 30 ± 3% indicating deposition of hydrogenated DLC (a-C:H) coatings. Coatings with good adhesion are achieved when using a multiple energy implantation regime. Raman spectroscopy results suggest slightly larger disordered DLC layers when using low ion energy, indicating higher sp(3) bonds in DLC coatings. The results show that commercially interesting coatings can be achieved in short time.

  17. Adhesion and differentiation of Saos-2 osteoblast-like cells on chromium-doped diamond-like carbon coatings.

    PubMed

    Filova, Elena; Vandrovcova, Marta; Jelinek, Miroslav; Zemek, Josef; Houdkova, Jana; Jan Remsa; Kocourek, Tomas; Stankova, Lubica; Bacakova, Lucie

    2017-01-01

    Diamond-like carbon (DLC) thin films are promising for use in coating orthopaedic, dental and cardiovascular implants. The problem of DLC layers lies in their weak layer adhesion to metal implants. Chromium is used as a dopant for improving the adhesion of DLC films. Cr-DLC layers were prepared by a hybrid technology, using a combination of pulsed laser deposition (PLD) from a graphite target and magnetron sputtering. Depending on the deposition conditions, the concentration of Cr in the DLC layers moved from zero to 10.0 at.%. The effect of DLC layers with 0.0, 0.9, 1.8, 7.3, 7.7 and 10.0 at.% Cr content on the adhesion and osteogenic differentiation of human osteoblast-like Saos-2 cells was assessed in vitro. The DLC samples that contained 7.7 and 10.0 at.% of Cr supported cell spreading on day 1 after seeding. On day three after seeding, the most apparent vinculin-containing focal adhesion plaques were also found on samples with higher concentrations of chromium. On the other hand, the expression of type I collagen and alkaline phosphatase at the mRNA and protein level was the highest on Cr-DLC samples with a lower concentration of Cr (0-1.8 at.%). We can conclude that higher concentrations of chromium supported cell adhesion; however DLC and DLC doped with a lower concentration of chromium supported osteogenic cell differentiation.

  18. Capacitively coupled RF diamond-like-carbon reactor

    DOEpatents

    Devlin, David James; Coates, Don Mayo; Archuleta, Thomas Arthur; Barbero, Robert Steven

    2000-01-01

    A process of coating a non-conductive fiber with diamond-like carbon, including passing a non-conductive fiber between a pair of parallel metal grids within a reaction chamber, introducing a hydrocarbon gas into the reaction chamber, forming a plasma within the reaction chamber for a sufficient period of time whereby diamond-like carbon is formed upon the non-conductive fiber, is provided together with a reactor chamber for deposition of diamond-like carbon upon a non-conductive fiber, including a vacuum chamber, a cathode assembly including a pair of electrically isolated opposingly parallel metal grids spaced apart at a distance of less than about 1 centimeter, an anode, a means of introducing a hydrocarbon gas into said vacuum chamber, and a means of generating a plasma within said vacuum chamber.

  19. Fabrication of highly transparent diamond-like carbon anti-reflecting coating for Si solar cell application

    SciTech Connect

    Banerjee, Amit Das, Debajyoti

    2014-04-24

    ARC grade highly transparent unhydrogenated diamond-like carbon (DLC) films were produced, directly from a-C target, using RF magnetron sputtering deposition technique, for optoelectronic applications. Optical band gap, transmittance, reflectance, sp{sup 3} fraction, I{sub D}/I{sub G}, density, and refractive index of the films have been estimated with the help of optical tools like Uv-vis spectrophotometer, ellipsometer and micro-Raman. Optimum ARC-qualities have been identified in low-temperature grown DLC films at an Ar pressure of 4 mTorr in the reactor, accomplishing its key requirements for use in silicon solar cells.

  20. Method for producing fluorinated diamond-like carbon films

    DOEpatents

    Hakovirta, Marko J.; Nastasi, Michael A.; Lee, Deok-Hyung; He, Xiao-Ming

    2003-06-03

    Fluorinated, diamond-like carbon (F-DLC) films are produced by a pulsed, glow-discharge plasma immersion ion processing procedure. The pulsed, glow-discharge plasma was generated at a pressure of 1 Pa from an acetylene (C.sub.2 H.sub.2) and hexafluoroethane (C.sub.2 F.sub.6) gas mixture, and the fluorinated, diamond-like carbon films were deposited on silicon <100>substrates. The film hardness and wear resistance were found to be strongly dependent on the fluorine content incorporated into the coatings. The hardness of the F-DLC films was found to decrease considerably when the fluorine content in the coatings reached about 20%. The contact angle of water on the F-DLC coatings was found to increase with increasing film fluorine content and to saturate at a level characteristic of polytetrafluoroethylene.

  1. Magnetism in diamond-like carbon

    NASA Astrophysics Data System (ADS)

    Saito, Tetsuji; Ozeki, Takeshi; Terashima, Keiichi

    2005-12-01

    We report the magnetization of diamond-like carbon (DLC) produced by the rf plasma-enhanced CVD method. The magnetization of DLC film was found to be diamagnetic when it was deposited on a silicon substrate. On the other hand, DLC film showed ferromagnetic behavior when deposited on a stainless steel substrate. Chemical analysis confirmed that the magnetization of the DLC film was not due to contamination from the substrate. Raman spectrometry studies revealed that the DLC film deposited on the stainless steel substrate has a higher ratio of disordered peak ( ID) to graphite-like peak ( IG) than that deposited on the silicon substrate.

  2. Apparatus for producing diamond-like carbon flakes

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor)

    1986-01-01

    A vacuum arc from a spot at the face of a graphite cathode to a graphite anode produces a beam of carbon ions and atoms. A carbon coating from this beam is deposited on an ion beam sputtered target to produce diamond-like carbon flakes. A graphite tube encloses the cathode, and electrical isolation is provided by an insulating sleeve. The tube forces the vacuum arc spot to be confined to the surface on the outermost end of the cathode. Without the tube the arc spot will wander to the side of the cathode. This spot movement results in low rates of carbon deposition, and the properties of the deposited flakes are more graphite-like than diamond-like.

  3. Wear of ultra-high molecular weight polyethylene against damaged and undamaged stainless steel and diamond-like carbon-coated counterfaces.

    PubMed

    Firkins, P; Hailey, J L; Fisher, J; Lettington, A H; Butter, R

    1998-10-01

    The wear of ultra-high molecular weight polyethylene (UHMWPE) in artificial joints and the resulting wear debris-induced osteolysis remains a major clinical concern in the orthopaedic sector. Third-body damage of metallic femoral heads is often cited as a cause of accelerated polyethylene wear, and the use of ceramic femoral heads in the hip is gaining increasing favour. In the knee prostheses and for smaller diameter femoral heads, the application of hard surface coatings, such as diamond-like carbon, is receiving considerable attention. However, to date, there has been little or no investigation of the tribology of these coatings in simulated biological environments. In this study, diamond-like carbon (DLC) has been compared to stainless steel in its undamaged form and following simulated third-body damage. The wear of UHMWPE was found to be similar when sliding against undamaged DLC and stainless steel counterfaces. DLC was found to be much more damage resistant than DLC. Under test conditions that simulate third-body damage to the femoral head, the wear of UHMWPE was seven times lower against DLC than against stainless steel (P < 0.05). The study shows DLC has considerable potential as a femoral bearing surface in artificial joints.

  4. Investigating the functionality of diamond-like carbon films on an artificial heart diaphragm.

    PubMed

    Ohgoe, Yasuharu; Takada, Satoshi; Hirakuri, Kenji K; Tsuchimoto, Katsuya; Homma, Akihiko; Miyamatsu, Toshinobu; Saitou, Tomoyuki; Friedbacher, Gernot; Tatsumi, Eisuke; Taenaka, Yoshiyuki; Fukui, Yasuhiro

    2003-01-01

    In this study, the authors used diamond-like carbon film to coat the ellipsoidal diaphragm (polyurethane elastomer) of artificial hearts. The purpose of such coatings is to prevent the penetration of hydraulic silicone oil and blood through the diaphragm. To attach diamond-like carbon film uniformly on the diaphragm, the authors developed a special electrode. In estimating the uniformity of the diamond-like carbon film, the thickness was measured using a scanning electron microscope, and the characteristics of the diamond-like carbon film was investigated using infrared spectroscopy, Ar-laser Raman spectrophotometer, and x-ray photoelectron spectrometer. Also, to estimate the penetration of silicone oil through the diaphragm, in vitro testing was operated by alternating the pressure of silicone oil for 20 days. The authors were able to successfully attach uniform deposition of diamond-like carbon film on the ellipsoidal diaphragm. In this in vitro test, diamond-like carbon film was proven to have good stability. The amount of silicone oil penetration was improved by one-third using the diamond-like carbon film coating compared with an uncoated diaphragm. It is expected that through the use of the diamond-like carbon film, the dynamic compatibility of an artificial heart diaphragm will increase.

  5. Ti-doped hydrogenated diamond like carbon coating deposited by hybrid physical vapor deposition and plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Lee, Na Rae; Sle Jun, Yee; Moon, Kyoung Il; Sunyong Lee, Caroline

    2017-03-01

    Diamond-like carbon films containing titanium and hydrogen (Ti-doped DLC:H) were synthesized using a hybrid technique based on physical vapor deposition (PVD) and plasma enhanced chemical vapor deposition (PECVD). The film was deposited under a mixture of argon (Ar) and acetylene gas (C2H2). The amount of Ti in the Ti-doped DLC:H film was controlled by varying the DC power of the Ti sputtering target ranging from 0 to 240 W. The composition, microstructure, mechanical and chemical properties of Ti-doped DLC:H films with varying Ti concentrations, were investigated using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), nano indentation, a ball-on-disk tribometer, a four-point probe system and dynamic anodic testing. As a result, the optimum composition of Ti in Ti-doped DLC:H film using our hybrid method was found to be a Ti content of 18 at. %, having superior electrical conductivity and high corrosion resistance, suitable for bipolar plates. Its hardness value was measured to be 25.6 GPa with a low friction factor.

  6. Adsorptive properties of albumin, fibrinogen, and gamma-globulin on fluorinated diamond-like carbon films coated on PTFE.

    PubMed

    Ozeki, K; Nagashima, I; Hirakuri, K K; Masuzawa, T

    2010-05-01

    Fluorinated diamond-like carbon (F-DLC) films were deposited on polytetrafluoroethylene (PTFE) using radio frequency (RF) plasma-enhanced chemical vapor deposition (CVD) by changing the ratio of tetrafluoromethane (CF(4)) and methane (CH(4)). To enhance the adhesion strength of the F-DLC film to the PTFE substrate, the PTFE surface was modified with a N(2) plasma pre-treatment. XPS analysis of the films showed that the C-C bond decreased with increases in the CF(4) ratio, whereas the C-F bond increased with the CF(4) ratio. The F/C ratio of the film also increased with the CF(4) ratio. The pull-out test showed that the adhesion strengths of the films (CF(4)-0-60%) were improved with the plasma pre-treatment. In the film without the plasma pre-treatment, adhesion strength increased with the CF(4) ratio. In contrast, in the case with the plasma pre-treatment, the adhesion strength of the F-DLC film decreased with the increased CF(4) ratio. Regarding the adsorption of albumin, fibrinogen, and gamma-globulin, the amount of adsorbed albumin on the film decreased with an increasing CF(4) ratio, and the amount of adsorbed fibrinogen and gamma-globulin increased with the CF(4) ratio. The CF(4)-0% DLC film showed the most adsorbed albumin and the least adsorbed fibrinogen and gamma-globulin. This indicates that the CF(4)-0% DLC film has higher anti-thrombogenicity than the F-DLC film.

  7. Electronic devices from diamond-like carbon

    NASA Astrophysics Data System (ADS)

    Milne, W. I.

    2003-03-01

    This paper reviews the work carried out over the past few years on the application of diamond-like carbon (DLC) materials to electronic devices. The use of such materials is still in its infancy due to their high defect state density and associated low mobilities. To date, the major effort in the electronic field has been in their attempted use as cold cathode field emitters where their low threshold field has attracted much attention. However, attempts have also been made to produce metal semiconductor metal structures, diodes, a-C/c-Si heterostructures and thin film transistors with varying degrees of success. A brief review of work carried out on the use of DLCs in solar cell manufacture will also be presented but it seems at this early stage in their development that the most promising area for future development will be in the field of microelectromechanical structures where their friction, stiction and wear properties make them prime candidates for use in moving mechanical assemblies.

  8. Graphene diamond-like carbon films heterostructure

    SciTech Connect

    Zhao, Fang; Afandi, Abdulkareem; Jackman, Richard B.

    2015-03-09

    A limitation to the potential use of graphene as an electronic material is the lack of control over the 2D materials properties once it is deposited on a supporting substrate. Here, the use of Diamond-like Carbon (DLC) interlayers between the substrate and the graphene is shown to offer the prospect of overcoming this problem. The DLC films used here, more properly known as a-C:H with ∼25% hydrogen content, have been terminated with N or F moieties prior to graphene deposition. It is found that nitrogen terminations lead to an optical band gap shrinkage in the DLC, whilst fluorine groups reduce the DLC's surface energy. CVD monolayer graphene subsequently transferred to DLC, N terminated DLC, and F terminated DLC has then been studied with AFM, Raman and XPS analysis, and correlated with Hall effect measurements that give an insight into the heterostructures electrical properties. The results show that different terminations strongly affect the electronic properties of the graphene heterostructures. G-F-DLC samples were p-type and displayed considerably higher mobility than the other heterostructures, whilst G-N-DLC samples supported higher carrier densities, being almost metallic in character. Since it would be possible to locally pattern the distribution of these differing surface terminations, this work offers the prospect for 2D lateral control of the electronic properties of graphene layers for device applications.

  9. Improving the high frequency response of a loudspeaker using hydrogen-free diamond-like carbon film coating at low temperature

    NASA Astrophysics Data System (ADS)

    Lin, ChiiRuey; Liu, ShinHwa; Liou, WangJeng; Chang, ChienKuo

    2012-03-01

    Hydrogen-free diamond-like carbon (DLC) thin films were deposited at low temperature (less than 100°C) by an RF magnetron sputtering facility. DLC films have the ability to change the sound velocity ( E/ρ) in loudspeakers for applications of hard coating. The hydrogen-free DLC films were coated onto PEI diaphragm substrates. The I D/ I G ratio and the surface roughness are 2.09 and less than 0.86 nm ( Ra) with a scanning area of 50 μm×50 μm, respectively. Frequency response analysis of the DLC films on the diaphragm shows that the high frequency response increases by 0.2 dB-5.1 dB (6 kHz-11.2 kHz), -0.4 dB-1.8 dB (11.8 kHz-20 kHz) on average. On the basis of the results of this study, we validated that it was feasible to sputter hydrogen-free DLC films on polymer substrates for mass production. These results also provided useful parameters for future applications of electro-acoustic devices.

  10. Allergen diagnosis microarray with high-density immobilization capacity using diamond-like carbon-coated chips for profiling allergen-specific IgE and other immunoglobulins.

    PubMed

    Suzuki, Koichi; Hiyoshi, Mineyoshi; Tada, Hitomi; Bando, Miwa; Ichioka, Takao; Kamemura, Norio; Kido, Hiroshi

    2011-11-14

    The diagnosis of antibody-mediated allergic disorders is based on clinical findings, skin prick tests and detection of allergen-specific IgE in serum. Here, we present a new microarray technique of high-density antigen immobilization using carboxylated arms on the surface of a diamond-like carbon (DLC)-coated chip. High immobilization capacity of antigen on DLC chip at (0.94-7.82)×10(9) molecules mm(-2) allowed the analysis of allergen-specific immunoglobulins against not only purified proteins but also natural allergen extracts with wide assay dynamic range. The higher sensitivity of the allergen-specific IgE detection on DLC chip was observed for comparison with the UniCAP system: the DLC chip allowed lowering the limit of dilution rate in UniCAP system to further dilution at 4-8-fold. High correlations (ρ>0.9-0.85) of allergen-specific IgE values determined by the DLC chip and UniCAP were found in most of 20 different allergens tested. The DLC chip was useful to determine allergen-induced antibodies of IgA, IgG, IgG1, and IgG4 in sera, apart from IgE, as well as secretory IgA in saliva against the same series of allergens on the chip in a minimal amount (1-2 μL) of sample.

  11. Formation of conducting nanochannels in diamond-like carbon films

    NASA Astrophysics Data System (ADS)

    Evtukh, A.; Litovchenko, V.; Semenenko, M.; Yilmazoglu, O.; Mutamba, K.; Hartnagel, H. L.; Pavlidis, D.

    2006-09-01

    A sharp increase of the emission current at high electric fields and a decrease of the threshold voltage after pre-breakdown conditioning of diamond-like carbon (DLC) films have been measured. This effect was observed for DLC-coated silicon tips and GaAs wedges. During electron field emission (EFE) at high electric fields the energy barriers caused by an sp3 phase between sp2 inclusions can be broken, resulting in the formation of conducting nanochannels between the semiconductor-DLC interface and the surface of the DLC film. At high current densities and the resulting local heating, the diamond-like sp3 phase transforms into a conducting graphite-like sp2 phase. As a result an electrical conducting nanostructured channel is formed in the DLC film. The diameter of the conducting nanochannel was estimated from the reduced threshold voltage after pre-breakdown conditioning to be in the range of 5-25 nm. The presence of this nanochannel in an insulating matrix leads to a local enhancement of the electric field and a reduced threshold voltage for EFE. Based on the observed features an efficient method of conducting nanochannel matrix formation in flat DLC films for improved EFE efficiency is proposed. It mainly uses a silicon tip array as an upper electrode in contact with the DLC film. The formation of nanochannels starts at the interface between the tips and the DLC film. This opens new possibilities of aligned and high-density conducting channel formation.

  12. Photochemically modified diamond-like carbon surfaces for neural interfaces.

    PubMed

    Hopper, A P; Dugan, J M; Gill, A A; Regan, E M; Haycock, J W; Kelly, S; May, P W; Claeyssens, F

    2016-01-01

    Diamond-like carbon (DLC) was modified using a UV functionalization method to introduce surface-bound amine and aldehyde groups. The functionalization process rendered the DLC more hydrophilic and significantly increased the viability of neurons seeded to the surface. The amine functionalized DLC promoted adhesion of neurons and fostered neurite outgrowth to a degree indistinguishable from positive control substrates (glass coated with poly-L-lysine). The aldehyde-functionalized surfaces performed comparably to the amine functionalized surfaces and both additionally supported the adhesion and growth of primary rat Schwann cells. DLC has many properties that are desirable in biomaterials. With the UV functionalization method demonstrated here it may be possible to harness these properties for the development of implantable devices to interface with the nervous system.

  13. Prospective multi-center registry to evaluate efficacy and safety of the newly developed diamond-like carbon-coated cobalt-chromium coronary stent system.

    PubMed

    Ando, Kenji; Ishii, Katsuhisa; Tada, Eiji; Kataoka, Kazuaki; Hirohata, Atsushi; Goto, Kenji; Kobayashi, Katsuyuki; Tsutsui, Hiroshi; Nakahama, Makoto; Nakashima, Hitoshi; Uchikawa, Shinichiroh; Kanda, Junji; Yasuda, Satoshi; Yajima, Junji; Kitabayashi, Hiroshi; Sakurai, Shumpei; Nakanishi, Keita; Inoue, Naoto; Noike, Hirofumi; Hasebe, Terumitsu; Sato, Tetsuya; Yamasaki, Masao; Kimura, Takeshi

    2016-07-22

    The purpose of this multi-center, non-randomized, and open-label clinical trial was to determine the non-inferiority of diamond-like carbon (DLC)-coated cobalt-chromium coronary stent, the MOMO DLC coronary stent, relative to commercially available bare-metal stents (MULTI-LINK VISION(®)). Nineteen centers in Japan participated. The study cohort consisted of 99 patients from 19 Japanese centers with single or double native coronary vessel disease with de novo and restenosis lesions who met the study eligibility criteria. This cohort formed the safety analysis set. The efficacy analysis set consisted of 98 patients (one case was excluded for violating the eligibility criteria). The primary endpoint was target vessel failure (TVF) rate at 9 months after stent placement. Of the 98 efficacy analysis set patients, TVF occurred in 11 patients (11.2 %, 95 % confidence interval 5.7-19.2 %) at 9 months after the index stent implantation. The upper 95 % confidence interval for TVF of the study stent was lower than that previously reported for the commercially available MULTI-LINK VISION(®) (19.6 %), demonstrating non-inferiority of the study stent to MULTI-LINK VISION(®). All the TVF cases were related to target vascular revascularization. None of the cases developed in-stent thrombosis or myocardial infarction. The average in-stent late loss and binary restenosis rate at the 6-month follow-up angiography were 0.69 mm and 10.5 %, respectively, which are lower than the reported values for commercially available bare-metal stents. In conclusion, the current pivotal clinical study evaluating the new MOMO DLC-coated coronary stent suggested its low rates of TVF and angiographic binary restenosis, and small in-stent late loss, although the data were considered preliminary considering the small sample size and single arm study design.

  14. The effect of nitrogen and oxygen plasma on the wear properties and adhesion strength of the diamond-like carbon film coated on PTFE

    NASA Astrophysics Data System (ADS)

    Ozeki, K.; Hirakuri, K. K.

    2008-01-01

    Diamond-like carbon (DLC) films were deposited on polytetrafluoroethylene (PTFE) using a radiofrequency plasma chemical vapour deposition method. Prior to DLC coating, the PTFE substrates were modified with O 2 and N 2 plasma to enhance the adhesion strength of the DLC film to the substrate. The effect of the plasma pre-treatment on the chemical composition and the surface energy of the plasma pre-treated PTFE surface was investigated by X-ray photoelectron spectroscopy (XPS) and static water contact angle measurement, respectively. A pull-out test and a ball-on-disc test were carried out to evaluate the adhesion strength and the wear properties of the DLC-coated PTFE. In the N 2 plasma pre-treatment, the XPS result indicated that defluorination and the nitrogen grafting occurred on the plasma pre-treated PTFE surface, and the water contact angle decreased with increasing the plasma pre-treatment time. In the O 2 plasma pre-treatment, no grafting of the oxygen occurred, and the water contact angle slightly increased with the treatment time. In the pull-out test, the adhesion strength of the DLC film to the PTFE substrate was improved with the plasma pre-treatment to the PTFE substrate, and N 2 plasma pre-treatment was more effective than the O 2 plasma pre-treatment. In the ball-on-disc test, the DLC film with the N 2 plasma pre-treatment showed good wear resistance, compared with that with O 2 plasma pre-treatment.

  15. Plasma deposited diamond-like carbon films for large neutralarrays

    SciTech Connect

    Brown, I.G.; Blakely, E.A.; Bjornstad, K.A.; Galvin, J.E.; Monteiro, O.R.; Sangyuenyongpipat, S.

    2004-07-15

    To understand how large systems of neurons communicate, we need to develop methods for growing patterned networks of large numbers of neurons. We have found that diamond-like carbon thin films formed by energetic deposition from a filtered vacuum arc carbon plasma can serve as ''neuron friendly'' substrates for the growth of large neural arrays. Lithographic masks can be used to form patterns of diamond-like carbon, and regions of selective neuronal attachment can form patterned neural arrays. In the work described here, we used glass microscope slides as substrates on which diamond-like carbon was deposited. PC-12 rat neurons were then cultured on the treated substrates and cell growth monitored. Neuron growth showed excellent contrast, with prolific growth on the treated surfaces and very low growth on the untreated surfaces. Here we describe the vacuum arc plasma deposition technique employed, and summarize results demonstrating that the approach can be used to form large patterns of neurons.

  16. Effects of bias voltage on diamond like carbon coatings deposited using titanium isopropoxide (TIPOT) and acetylene/argon mixtures onto various substrate materials.

    PubMed

    Said, R; Ghumman, C A A; Teodoro, M N D; Ahmed, W; Abuazza, A; Gracio, J

    2010-04-01

    RF-PECVD was used to prepare amorphous of carbon (DLC) onto stainless steel 316 and glass substrates. The substrates were negatively biased at between 100 V to 400 V. Thin films of DLC have been deposited using C2H2 and titanium isopropoxide (TIPOT). Argon was used to generate the plasma in the PECVD system chamber. DEKTAK 8 surface stylus profilometer was used to measure the film thickness and the deposition rate was calculated. Micro Raman spectroscopy was employed to determine the chemical structure and bonding present in the films. Composition analysis of the samples was carried out using VGTOF SIMS (IX23LS) instrument. In addition, X-ray photoelectron spectroscopy (XPS) was used to analyze the composition and chemical state of the films. The wettability of the films was examined using the optical contact angle meter (CAM200) system. Two types of liquids with different polarities were used to study changes in the surface energy. The as-grown films were in the thickness range of 200-400 nm. Raman spectroscopy results showed that the I(D)/I(G) ratio decreased when the bias voltage on the stainless steel substrates was increased. This indicates an increase in the graphitic nature of the film deposited. In contrast, on the glass substrates the I(D)/I(G) ratio increased when the bias voltage was increased indicates a greater degree of diamond like character. Chemical composition determined using XPS showed the presence of carbon and oxygen in both samples on glass and stainless steel substrates. Both coatings the contact angle of the films decreased except for 400 V which showed a slight increase. The oxygen is thought to play an important role on the polar component of a-C.

  17. Electronic Power System Application of Diamond-Like Carbon Films

    NASA Technical Reports Server (NTRS)

    Wu, Richard L. C.; Kosai, H.; Fries-Carr, S.; Weimer, J.; Freeman, M.; Schwarze, G. E.

    2003-01-01

    A prototype manufacturing technology for producing high volume efficiency and high energy density diamond-like carbon (DLC) capacitors has been developed. Unique dual ion-beam deposition and web-handling systems have been designed and constructed to deposit high quality DLC films simultaneously on both sides of capacitor grade aluminum foil and aluminum-coated polymer films. An optimized process, using inductively coupled RF ion sources, has been used to synthesize electrically robust DLC films. DLC films are amorphous and highly flexible, making them suitable for the production of wound capacitors. DLC capacitors are reliable and stable over a wide range of AC frequencies from 20 Hz to 1 MHz, and over a temperature range from .500 C to 3000 C. The compact DLC capacitors offer at least a 50% decrease in weight and volume and a greater than 50% increase in temperature handling capability over equal value capacitors built with existing technologies. The DLC capacitors will be suitable for high temperature, high voltage, pulsed power and filter applications.

  18. Friction behavior of a multi-interface system and improved performance by AlMgB14–TiB2–C and diamond-like-carbon coatings

    DOE PAGES

    Qu, Jun; Blau, Peter J.; Higdon, Clifton; ...

    2016-03-29

    We investigated friction behavior of a bearing system with two interfaces involved: a roller component experiencing rolling–sliding interaction against twin cylinders under point contacts while simultaneously undergoing pure sliding interaction against a socket under a conformal contact. Lubrication modeling predicted a strong correlation between the roller's rolling condition and the system's friction behavior. Experimental observations first validated the analytical predictions using steel and iron components. Diamond-like-carbon (DLC) coating and AlMgB14–TiB2 coating with a carbon topcoat (BAMC) were then applied to the roller and twin cylinders, respectively. In conclusion, testing and analysis results suggest that the coatings effectively decreased the slipmore » ratio for the roller–cylinder contact and the sliding friction at both bearing interfaces and, as a result, significantly reduced the system frictional torque.« less

  19. Friction behavior of a multi-interface system and improved performance by AlMgB14–TiB2–C and diamond-like-carbon coatings

    SciTech Connect

    Qu, Jun; Blau, Peter J.; Higdon, Clifton; Cook, Bruce A.

    2016-03-29

    We investigated friction behavior of a bearing system with two interfaces involved: a roller component experiencing rolling–sliding interaction against twin cylinders under point contacts while simultaneously undergoing pure sliding interaction against a socket under a conformal contact. Lubrication modeling predicted a strong correlation between the roller's rolling condition and the system's friction behavior. Experimental observations first validated the analytical predictions using steel and iron components. Diamond-like-carbon (DLC) coating and AlMgB14–TiB2 coating with a carbon topcoat (BAMC) were then applied to the roller and twin cylinders, respectively. In conclusion, testing and analysis results suggest that the coatings effectively decreased the slip ratio for the roller–cylinder contact and the sliding friction at both bearing interfaces and, as a result, significantly reduced the system frictional torque.

  20. Magnetic tunnel junctions utilizing diamond-like carbon tunnel barriers

    NASA Astrophysics Data System (ADS)

    Cadieu, F. J.; Chen, Li; Li, Biao

    2002-05-01

    We have devised a method whereby thin particulate-free diamond-like carbon films can be made with good adhesion onto even room-temperature substrates. The method employs a filtered ionized carbon beam created by the vacuum impact of a high-energy, approximately 1 J per pulse, 248 nm excimer laser onto a carbon target. The resultant deposition beam can be steered and deflected by magnetic and electric fields to paint a specific substrate area. An important aspect of this deposition method is that the resultant films are particulate free and formed only as the result of atomic species impact. The vast majority of magnetic tunnel junctions utilizing thin metallic magnetic films have employed a thin oxidized layer of aluminum to form the tunnel barrier. This has presented reproducibility problems because the indicated optimal barrier thickness is only approximately 13 Å thick. Magnetic tunnel junctions utilizing Co and permalloy films made by evaporation and sputtering have been fabricated with an intervening diamond-like carbon tunnel barrier. The diamond-like carbon thickness profile has been tapered so that seven junctions with different barrier thickness can be formed at once. Magnetoresistive (MR) measurements made between successive permalloy strip ends include contributions from two junctions and from the permalloy and Co strips that act as current leads to the junctions. Magnetic tunnel junctions with thicker carbon barriers exhibit MR effects that are dominated by that of the permalloy strips. Since these tunnel barriers are formed without the need for oxygen, complete tunnel junctions can be formed with all high-vacuum processing.

  1. Method and apparatus for making diamond-like carbon films

    DOEpatents

    Pern, Fu-Jann; Touryan, Kenell J.; Panosyan, Zhozef Retevos; Gippius, Aleksey Alekseyevich

    2008-12-02

    Ion-assisted plasma enhanced deposition of diamond-like carbon (DLC) films on the surface of photovoltaic solar cells is accomplished with a method and apparatus for controlling ion energy. The quality of DLC layers is fine-tuned by a properly biased system of special electrodes and by exact control of the feed gas mixture compositions. Uniform (with degree of non-uniformity of optical parameters less than 5%) large area (more than 110 cm.sup.2) DLC films with optical parameters varied within the given range and with stability against harmful effects of the environment are achieved.

  2. Diamond-Like Carbon Nanorods and Fabrication Thereof

    NASA Technical Reports Server (NTRS)

    Varshney, Deepak (Inventor); Makarov, Vladimir (Inventor); Morell, Gerardo (Inventor); Saxena, Puja (Inventor); Weiner, Brad (Inventor)

    2017-01-01

    Novel sp. (sup 3) rich diamond-like carbon (DLC) nanorod films were fabricated by hot filament chemical vapor deposition technique. The results are indicative of a bottom-up self-assembly synthesis process, which results in a hierarchical structure that consists of microscale papillae comprising numerous nanorods. The papillae have diameters ranging from 2 to 4 microns and the nanorods have diameters in the 35-45 nanometer range. A growth mechanism based on the vapor liquid-solid mechanism is proposed that accounts for the morphological aspects in the micro- and nano-scales.

  3. Tribological properties of amorphous hydrogenated (a-C:H) and hydrogen-free tetrahedral (ta-C) diamond-like carbon coatings under jatropha biodegradable lubricating oil at different temperatures

    NASA Astrophysics Data System (ADS)

    Mobarak, H. M.; Masjuki, H. H.; Mohamad, E. Niza; Kalam, M. A.; Rashedul, H. K.; Rashed, M. M.; Habibullah, M.

    2014-10-01

    The application of diamond-like carbon (DLC) coatings on automotive components is emerging as a favorable strategy to address the recent challenges in the industry. DLC coatings can effectively lower the coefficient of friction (CoF) and wear rate of engine components, thereby improving their fuel efficiency and durability. The lubrication of ferrous materials can be enhanced by a large amount of unsaturated and polar components of oils. Therefore, the interaction between nonferrous coatings (e.g., DLC) and vegetable oil should be investigated. A ball-on-plate tribotester was used to run the experiments. Stainless steel plates coated with amorphous hydrogenated (a-C:H) DLC and hydrogen-free tetrahedral (ta-C) DLC that slide against 440C stainless steel ball were used to create a ball-on-plate tribotester. The wear track was investigated through scanning electron microscopy. Energy dispersive and X-ray photoelectron spectroscopies were used to analyze the tribofilm inside the wear track. Raman analysis was performed to investigate the structural changes in the coatings. At high temperatures, the CoF in both coatings decreased. The wear rate, however, increased in the a-C:H but decreased in the ta-C DLC-coated plates. The CoF and the wear rate (coated layer and counter surface) were primarily influenced by the graphitization of the coating. Tribochemical films, such as polyphosphate glass, were formed in ta-C and acted as protective layers. Therefore, the wear rate of the ta-C DLC was lower than that of the-C:H DLC.

  4. Diamond-like nanocomposite coatings for LIGA-fabricated nickel alloy parts.

    SciTech Connect

    Prasad, Somuri V.; Scharf, Thomas W.

    2005-03-01

    A commercial plasma enhanced chemical vapor deposition (PECVD) technique with planetary substrate rotation was used to apply a thin (200-400 nm thick) conformal diamond-like carbon (DLC) coating (known as a diamond-like nanocomposite (DLN)) on LIGA fabricated Ni-Mn alloy parts. The PECVD technique is known to overcome the drawbacks associated with the line-of-sight nature of physical vapor deposition (PVD) and substrate heating inherent with traditional chemical vapor deposition (CVD). The purpose of the present study is to characterize the coverage, adhesion, and tribological (friction and wear) behavior of DLN coatings applied to planar and sidewall surfaces of small featured LIGA Ni-Mn fabricated parts, e.g. 280 {micro}m thick sidewalls. Friction and wear tests were performed in dry nitrogen, dry air, and air with 50% RH at Hertzian contact pressures ranging from 0.3 to 0.6 GPa. The friction coefficient of bare Ni-Mn alloy was determined to be 0.9. In contrast, low friction coefficients ({approx}0.02 in dry nitrogen and {approx}0.2 in 50% RH air) and minimal amount of wear were exhibited for the DLN coated LIGA Ni-Mn alloy parts and test coupons. This behavior was due to the ability of the coating to transfer to the rubbing counterface providing low interfacial shear at the sliding contact; resultantly, coating one surface was adequate for low friction and wear. In addition, a 30 nm thick titanium bond layer was determined to be necessary for good adhesion of DLN coating to Ni-Mn alloy substrates. Raman spectroscopy and cross-sectional SEM with energy dispersive x-ray analysis revealed that the DLN coatings deposited by the PECVD with planetary substrate rotation covered both the planar and sidewall surfaces of LIGA fabricated parts, as well as narrow holes of 300 {micro}m (0.012 inch) diameter.

  5. Low voltage electrodeposition of diamond like carbon (DLC)

    NASA Astrophysics Data System (ADS)

    Sreejith, K.; Nuwad, J.; Pillai, C. G. S.

    2005-10-01

    Attempt has been made to deposit diamond like carbon (DLC) films from ethanol through electrodeposition at low voltages (80-300 V) at 1 mm interelectrode separation. The films were characterized by atomic force microscopy (AFM), Scanning electron microscopy (SEM), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy and Auger electron Spectroscopy (AES). AFM investigations revealed the grain sizes are of tens of nanometers. The films were found to be continuous, smooth and close packed. Presence of peaks at 2958, 2929 and 2869 cm -1 in FTIR spectrum indicates the bonding states to be of predominantly sp 3 type (C-H). Raman spectroscopy analysis revealed two broad bands at ˜1350 and ˜1570 cm -1. The downshift of the G-band of graphite is indicative of presence of DLC. Analysis of the Raman spectra for the samples revealed an improvement in the film quality with increase in the voltage. Micro Raman investigations indicate the formation of diamond phase at the deposition potential of 80 V. The sp 2 contents the films calculated from Auger electron spectra were calculated and were found to be 31, 19 and 7.8% for the samples prepared at 80, 150 and 300 V, respectively. A tentative mechanism for the formation of DLC has been proposed. These results indicate the possibility of deposition of DLC at low voltage.

  6. Bacterial adhesion to diamond-like carbon as compared to stainless steel.

    PubMed

    Soininen, Antti; Tiainen, Veli-Matti; Konttinen, Yrjö T; van der Mei, Henny C; Busscher, Henk J; Sharma, Prashant K

    2009-08-01

    Recent studies suggest that diamond-like carbon (DLC) coatings are suitable candidates for application on biomedical devices and implants, due to their high hardness, low friction, high wear and corrosion resistance, chemical inertness, smoothness, and tissue and blood compatibility. However, most studies have neglected the potential susceptibility of DLC coatings to bacterial adhesion, which is the first step in the development of implant-related infections. This study compares adhesion of seven bacterial strains, commonly implicated in implant-related infections, to tetrahedral amorphous carbon, with their adhesion to AISI 316L surgical steel. The results show that bacterial adhesion to DLC was similar to the adhesion to commonly used stainless steel. This suggests that DLC coating can be advantageously used on implants made of AISI 316L or other materials without increasing the risk to implant-related infections.

  7. Workshop on diamond and diamond-like-carbon films for the transportation industry

    SciTech Connect

    Nichols, F.A.; Moores, D.K.

    1993-01-01

    Applications exist in advanced transportation systems as well as in manufacturing processes that would benefit from superior tribological properties of diamond, diamond-like-carbon and cubic boron nitride coatings. Their superior hardness make them ideal candidates as protective coatings to reduce adhesive, abrasive and erosive wear in advanced diesel engines, gas turbines and spark-ignited engines and in machining and manufacturing tools as well. The high thermal conductivity of diamond also makes it desirable for thermal management not only in tribological applications but also in high-power electronic devices and possibly large braking systems. A workshop has been recently held at Argonne National Laboratory entitled ``Diamond and Diamond-Like-Carbon Films for Transportation Applications`` which was attended by 85 scientists and engineers including top people involved in the basic technology of these films and also representatives from many US industrial companies. A working group on applications endorsed 18 different applications for these films in the transportation area alone. Separate abstracts have been prepared.

  8. Deposition And Characterization Of Ultra Thin Diamond Like Carbon Films

    NASA Astrophysics Data System (ADS)

    Tomcik, B.

    2010-07-01

    Amorphous hydrogenated and/or nitrogenated carbon films, a-C:H/a-C:N, in overall thickness up to 2 nm are materials of choice as a mechanical and corrosion protection layer of the magnetic media in modern hard disk drive disks. In order to obtain high density and void-free films the sputtering technology has been replaced by different plasma and ion beam deposition techniques. Hydrocarbon gas precursors, like C2H2 or CH4 with H2 and N2 as reactive gases are commonly used in Kaufman DC ion and RF plasma beam sources. Optimum incident energy of carbon ions, C+, is up to 100 eV while the typical ion current densities during the film formation are in the mA/cm2 range. Other carbon deposition techniques, like filtered cathodic arc, still suffer from co-deposition of fine nanosized carbon clusters (nano dust) and their improvements are moving toward arc excitation in the kHz and MHz frequency range. Non-destructive film analysis like μ-Raman optical spectroscopy, spectroscopic ellipsometry, FTIR and optical surface analysis are mainly used in the carbon film characterization. Due to extreme low film thicknesses the surface enhanced Raman spectroscopy (SERS) with pre-deposited layer of Au can reduce the signal collection time and minimize photon-induced damage during the spectra acquisition. Standard approach in the μ-Raman film evaluation is the measurement of the position (shift) and area of D and G-peaks under the deconvoluted overall carbon spectrum. Also, a slope of the carbon spectrum in the 1000-2000 cm-1 wavenumber range is used as a measure of the hydrogen intake within a film. Diamond like carbon (DLC) film should possess elasticity and self-healing properties during the occasional crash of the read-write head flying only couple of nanometers above the spinning film. Film corrosion protection capabilities are mostly evaluated by electrochemical tests, potentio-dynamic and linear polarization method and by business environmental method. Corrosion mechanism

  9. Proceedings of the DARPA (Defense Advanced Research Projects Agency) Workshop on Diamond-Like Carbon Coatings, held at Albuquerque, New Mexico on April 19-20, 1982,

    DTIC Science & Technology

    1982-01-01

    structural models proposed for a-C. Diffraction methods appear to be capable of giving very precise answers if the data are obtained out to sufficiently viii...Fundamental Questions (a) sp3 vs sp2 bonding (b) Intrinsic vs extrinsic absorption (c) Coating microstructure, amorphousness vs polycrystallinity (d) Role...deposition methods (g) Role of implantation, surface cleaning and surface conditioning 2 "e ..:..:. Priority DoD Applications (a) AR coatings for 8-12 um low

  10. Wear and Tribological Properties of Silicon-Containing Diamond-Like Carbon (Si-DLC) Coatings Synthesized with Nitrogen, Argon Plus Nitrogen, and Argon Ion Beams

    DTIC Science & Technology

    1998-06-01

    polymers on our Si-DLC coatings, we may attribute the improvements in properties to a consequence of cross-linking of the precursor material caused by the... ENGEN THAYERHALL WEST POINT NY 10996-1786 1 DIRECTOR US ARMY RESEARCH LAB AMSRLCSALTP 2800 POWDER MILL RD ADELPHI MD 20783-1145 1

  11. Fabrication of Semiordered Nanopatterned Diamond-like Carbon and Titania Films for Blood Contacting Applications.

    PubMed

    Nandakumar, Deepika; Bendavid, Avi; Martin, Philip J; Harris, Kenneth D; Ruys, Andrew J; Lord, Megan S

    2016-03-23

    Biomaterials with the ability to interface with, but not activate, blood components are essential for a multitude of medical devices. Diamond-like carbon (DLC) and titania (TiO2) have shown promise for these applications; however, both support platelet adhesion and activation. This study explored the fabrication of nanostructured DLC and TiO2 thin film coatings using a block copolymer deposition technique that produced semiordered nanopatterns with low surface roughness (5-8 nm Rrms). These surfaces supported fibrinogen and plasma protein adsorption that predominantly adsorbed between the nanofeatures and reduced the overall surface roughness. The conformation of the adsorbed fibrinogen was altered on the nanopatterned surfaces as compared with the planar surfaces to reveal higher levels of the platelet binding region. Planar DLC and TiO2 coatings supported less platelet adhesion than nanopatterned DLC and TiO2. However, platelets on the nanopatterned DLC coatings were less spread indicating a lower level of platelet activation on the nanostructured DLC coatings compared with the planar DLC coatings. These data indicated that nanostructured DLC coatings may find application in blood contacting medical devices in the future.

  12. Field emission, morphological and mechanical properties of variety of diamond-like carbon thin films

    NASA Astrophysics Data System (ADS)

    Dwivedi, Neeraj; Kumar, Sushil; Tripathi, R. K.; Malik, H. K.; Panwar, O. S.

    2011-11-01

    The effect of nitrogen incorporation and sandwich titanium and copper layers, on field emission, morphological and mechanical properties of diamond-like carbon (DLC) thin films is explored. The introduction of foreign element (N2) and sandwich Cu and Ti layers changed the amorphous morphology to nanostructured, reduced the stress, enhanced the hardness (except N2 incorporated DLC film) and improved the field emission (except Ti/DLC bilayer) of modified DLC films. The associated versatile electrical and mechanical properties of modified DLC film made it a material of great utility in the development of field emission display panels and also lead to its application as a hard and protective coating on cutting tools, automobile parts etc. It is important to mention that DLC-based electronic materials may replace currently used soft electronic materials (such as Si) due to their enhanced stability under high energy radiation.

  13. Covalent immobilization of protein onto a functionalized hydrogenated diamond-like carbon substrate.

    PubMed

    Biswas, Hari Shankar; Datta, Jagannath; Chowdhury, D P; Reddy, A V R; Ghosh, Uday Chand; Srivastava, Arvind Kumar; Ray, Nihar Ranjan

    2010-11-16

    Hydrogenated diamond-like carbon (HDLC) has an atomically smooth surface that can be deposited on high-surface area substrata and functionalized with reactive chemical groups, providing an ideal substrate for protein immobilization. A synthetic sequence is described involving deposition and hydrogenation of DLC followed by chemical functionalization. These functional groups are reacted with amines on proteins causing covalent immobilization on contact. Raman measurements confirm the presence of these surface functional groups, and Fourier transform infrared spectroscopy (FTIR) confirms covalent protein immobilization. Atomic force microscopy (AFM) of immobilized proteins is reproducible because proteins do not move as a result of interactions with the AFM probe-tip, thus providing an advantage over mica substrata typically used in AFM studies of protein. HDLC offers many of the same technical advantages as oxidized graphene but also allows for coating large surface areas of biomaterials relevant to the fabrication of medical/biosensor devices.

  14. The microstructure, mechanical and friction properties of protective diamond like carbon films on magnesium alloy

    NASA Astrophysics Data System (ADS)

    Zou, Y. S.; Wu, Y. F.; Yang, H.; Cang, K.; Song, G. H.; Li, Z. X.; Zhou, K.

    2011-12-01

    Protective hard coatings deposited on magnesium alloys are believed to be effective for overcoming their poor wear properties. In this work, diamond-like carbon (DLC) films as hard protective films were deposited on AZ91 magnesium alloy by arc ion plating under negative pulse bias voltages ranging from 0 to -200 V. The microstructure, composition and mechanical properties of the DLC films were analyzed by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and nanoindentation. The tribological behavior of uncoated and coated AZ91 magnesium alloy was investigated using a ball-on-disk tribotester. The results show that the negative pulse bias voltage used for film deposition has a significant effect on the sp3 carbon content and mechanical properties of the deposited DLC films. A maximum sp3 content of 33.3% was obtained at -100 V, resulting in a high hardness of 28.6 GPa and elastic modulus of 300.0 GPa. The DLC films showed very good adhesion to the AZ91 magnesium alloy with no observable cracks and delamination even during friction testing. Compared with the uncoated AZ91 magnesium alloy, the magnesium alloy coated with DLC films exhibits a low friction coefficient and a narrow, shallow wear track. The wear resistance and surface hardness of AZ91 magnesium alloy can be significantly improved by coating a layer of DLC protective film due to its high hardness and low friction coefficient.

  15. Deposition of hard and adherent diamond-like carbon films inside steel tubes using a pulsed-DC discharge.

    PubMed

    Trava-Airoldi, Vladimir Jesus; Capote, Gil; Bonetti, Luís Francisco; Fernandes, Jesum; Blando, Eduardo; Hübler, Roberto; Radi, Polyana Alves; Santos, Lúcia Vieira; Corat, Evaldo José

    2009-06-01

    A new, low cost, pulsed-DC plasma-enhanced chemical vapor deposition system that uses a bipolar, pulsed power supply was designed and tested to evaluate its capacity to produce quality diamond-like carbon films on the inner surface of steel tubes. The main focus of the study was to attain films with low friction coefficients, low total stress, a high degree of hardness, and very good adherence to the inner surface of long metallic tubes at a reasonable growth rate. In order to enhance the diamond-like carbon coating adhesion to metallic surfaces, four steps were used: (1) argon ion sputtering; (2) plasma nitriding; (3) a thin amorphous silicon interlayer deposition, using silane as the precursor gas; and (4) diamond-like carbon film deposition using methane atmosphere. This paper presents various test results as functions of the methane gas pressure and of the coaxial metal anode diameter, where the pulsed-DC voltage constant is kept constant. The influence of the coaxial metal anode diameter and of the methane gas pressure is also demonstrated. The results obtained showed the possibilities of using these DLC coatings for reduced friction and to harden inner surface of the steel tubes.

  16. Plasma spraying method for forming diamond and diamond-like coatings

    DOEpatents

    Holcombe, C.E.; Seals, R.D.; Price, R.E.

    1997-06-03

    A method and composition is disclosed for the deposition of a thick layer of diamond or diamond-like material. The method includes high temperature processing wherein a selected composition including at least glassy carbon is heated in a direct current plasma arc device to a selected temperature above the softening point, in an inert atmosphere, and is propelled to quickly quenched on a selected substrate. The softened or molten composition crystallizes on the substrate to form a thick deposition layer comprising at least a diamond or diamond-like material. The selected composition includes at least glassy carbon as a primary constituent and may include at least one secondary constituent. Preferably, the secondary constituents are selected from the group consisting of at least diamond powder, boron carbide (B{sub 4}C) powder and mixtures thereof. 9 figs.

  17. Plasma spraying method for forming diamond and diamond-like coatings

    DOEpatents

    Holcombe, Cressie E.; Seals, Roland D.; Price, R. Eugene

    1997-01-01

    A method and composition for the deposition of a thick layer (10) of diamond or diamond-like material. The method includes high temperature processing wherein a selected composition (12) including at least glassy carbon is heated in a direct current plasma arc device to a selected temperature above the softening point, in an inert atmosphere, and is propelled to quickly quenched on a selected substrate (20). The softened or molten composition (18) crystallizes on the substrate (20) to form a thick deposition layer (10) comprising at least a diamond or diamond-like material. The selected composition (12) includes at least glassy carbon as a primary constituent (14) and may include at least one secondary constituent (16). Preferably, the secondary constituents (16) are selected from the group consisting of at least diamond powder, boron carbide (B.sub.4 C) powder and mixtures thereof.

  18. Sticking non-stick: Surface and Structure control of Diamond-like Carbon in Plasma Enhanced Chemical Vapour Deposition

    NASA Astrophysics Data System (ADS)

    Jones, B. J.; Nelson, N.

    2016-10-01

    This short review article explores the practical use of diamond-like carbon (DLC) produced by plasma enhanced chemical vapour deposition (PECVD). Using as an example issues relating to the DLC coating of a hand-held surgical device, we draw on previous works using atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, tensiometry and electron paramagnetic resonance. Utilising data from these techniques, we examine the surface structure, substrate-film interface and thin film microstructure, such as sp2/sp3 ratio (graphitic/diamond-like bonding ratio) and sp2 clustering. We explore the variations in parameters describing these characteristics, and relate these to the final device properties such as friction, wear resistance, and diffusion barrier integrity. The material and device characteristics are linked to the initial plasma and substrate conditions.

  19. Deodorisation effect of diamond-like carbon/titanium dioxide multilayer thin films deposited onto polypropylene

    NASA Astrophysics Data System (ADS)

    Ozeki, K.; Hirakuri, K. K.; Masuzawa, T.

    2011-04-01

    Many types of plastic containers have been used for the storage of food. In the present study, diamond-like carbon (DLC)/titanium oxide (TiO2) multilayer thin films were deposited on polypropylene (PP) to prevent flavour retention and to remove flavour in plastic containers. For the flavour removal test, two types of multilayer films were prepared, DLC/TiO2 films and DLC/TiO2/DLC films. The residual gas concentration of acetaldehyde, ethylene, and turmeric compounds in bottle including the DLC/TiO2-coated and the DLC/TiO2/DLC-coated PP plates were measured after UV radiation, and the amount of adsorbed compounds to the plates was determined. The percentages of residual gas for acetaldehyde, ethylene, and turmeric with the DLC/TiO2 coated plates were 0.8%, 65.2% and 75.0% after 40 h of UV radiation, respectively. For the DLC/TiO2/DLC film, the percentages of residual gas for acetaldehyde, ethylene and turmeric decreased to 34.9%, 76.0% and 85.3% after 40 h of UV radiation, respectively. The DLC/TiO2/DLC film had a photocatalytic effect even though the TiO2 film was covered with the DLC film.

  20. Superlubricity mechanism of diamond-like carbon with glycerol. Coupling of experimental and simulation studies

    NASA Astrophysics Data System (ADS)

    DeBarros Bouchet, M. I.; Matta, C.; Le-Mogne, Th; Martin, J. Michel; Zhang, Q.; Goddard, W., III; Kano, M.; Mabuchi, Y.; Ye, J.

    2007-11-01

    We report a unique tribological system that produces superlubricity under boundary lubrication conditions with extremely little wear. This system is a thin coating of hydrogen-free amorphous Diamond-Like-Carbon (denoted as ta-C) at 353 K in a ta-C/ta-C friction pair lubricated with pure glycerol. To understand the mechanism of friction vanishing we performed ToF-SIMS experiments using deuterated glycerol and 13C glycerol. This was complemented by first-principles-based computer simulations using the ReaxFF reactive force field to create an atomistic model of ta-C. These simulations show that DLC with the experimental density of 3.24 g/cc leads to an atomistic structure consisting of a 3D percolating network of tetrahedral (sp3) carbons accounting for 71.5% of the total, in excellent agreement with the 70% deduced from our Auger spectroscopy and XANES experiments. The simulations show that the remaining carbons (with sp2 and sp1 character) attach in short chains of length 1 to 7. In sliding simulations including glycerol molecules, the surface atoms react readily to form a very smooth carbon surface containing OH-terminated groups. This agrees with our SIMS experiments. The simulations find that the OH atoms are mostly bound to surface sp1 atoms leading to very flexible elastic response to sliding. Both simulations and experiments suggest that the origin of the superlubricity arises from the formation of this OH-terminated surface.

  1. High rate PLD of diamond-like-carbon utilizing high repetition rate visible lasers

    SciTech Connect

    McLean, W. II; Fehring, E.J.; Dragon, E.P.; Warner, B.E.

    1994-09-15

    Pulsed Laser Deposition (PLD) has been shown to be an effective method for producing a wide variety of thin films of high-value-added materials. The high average powers and high pulse repetition frequencies of lasers under development at LLNL make it possible to scale-up PLD processes that have been demonstrated in small systems in a number of university, government, and private laboratories to industrially meaningful, economically feasible technologies. A copper vapor laser system at LLNL has been utilized to demonstrate high rate PLD of high quality diamond-like-carbon (DLC) from graphite targets. The deposition rates for PLD obtained with a 100 W laser were {approx} 2000 {mu}m{center_dot}cm{sup 2}/h, or roughly 100 times larger than those reported by chemical vapor deposition (CVD) or physical vapor deposition (PVD) methods. Good adhesion of thin (up to 2 pm) films has been achieved on a small number of substrates that include SiO{sub 2} and single crystal Si. Present results indicate that the best quality DLC films can be produced at optimum rates at power levels and wavelengths compatible with fiber optic delivery systems. If this is also true of other desirable coating systems, this PLD technology could become an extremely attractive industrial tool for high value added coatings.

  2. Method of synthesizing metal doped diamond-like carbon films

    NASA Technical Reports Server (NTRS)

    Ueno, Mayumi (Inventor); Sunkara, Mahendra Kumar (Inventor)

    2003-01-01

    A method of synthesizing metal doped carbon films by placing a substrate in a chamber with a selected amount of a metalorganic compound. An electron cyclotron resonance is applied to the chamber in order to vaporize the metalorganic compound. The resonance is applied to the chamber until a metal doped carbon film is formed. The metalorganic compound is preferably selected from the group consisting of an organic salt of ruthenium, palladium, gold or platinum.

  3. Argonne Discovery Yields Self-Healing Diamond-Like Carbon

    DOE PAGES

    Cunningham, Greg; Jones, Katie Elyce

    2016-10-27

    We report that large-scale reactive molecular dynamics simulations carried out on the US Department of Energy’s IBM Blue Gene/Q Mira supercomputer at the Argonne Leadership Computing Facility, along with experiments conducted by researchers in Argonne’s Energy Systems Division, enabled the design of a “self-healing” anti-wear coating that drastically reduces friction and related degradation in engines and moving machinery. Now, the computational work advanced for this purpose is being used to identify the friction-fighting potential of other catalysts.

  4. Electrical and magnetic properties of electrodeposited nickel incorporated diamond-like carbon thin films

    NASA Astrophysics Data System (ADS)

    Pandey, B.; Das, D.; Kar, A. K.

    2015-05-01

    Nanocomposite diamond-like carbon (DLC) thin films have been synthesized by incorporating nickel (Ni) nanoparticles in DLC matrix with varying concentration of nickel. DLC and Ni-DLC thin films have been deposited on ITO coated glass substrates employing low voltage electrodeposition method. Electrical properties of the samples were studied by measuring current-voltage characteristics and dielectric properties. The current approaches toward an ohmic behavior with metal addition. This tendency of increasing ohmicity is enhanced with increase in dilution of the electrolyte. The conductivity increases with Ni addition and interestingly it continues to increase with dilution of Ni concentration in the electrolyte in the range of our study. Magnetic properties for DLC and Ni-DLC thin film samples were examined by electron paramagnetic resonance (EPR) measurements and Super Conducting Quantum Interference Device (SQUID) measurements. g-Value for DLC is 2.074, whereas it decreases to 2.055 with Ni addition in the electrolyte. This decrement arises from the increased sp2 content in DLC matrix. The magnetic moment vs. magnetic field (m-H) curves of Ni-DLC indicate superparamagnetic behavior which may be due to ferromagnetic contribution from the incorporated nickel nanoparticles in the DLC matrix. The ZFC curve of Ni-DLC after the blocking temperature shows a combined contribution of ferromagnetic, superparamagnetic and paramagnetic nature of the materials persisting up to 300 K.

  5. Chemically modified diamond-like carbon (DLC) for protein enrichment and profiling by MALDI-MS.

    PubMed

    Najam-ul-Haq, M; Rainer, M; Huck, C W; Ashiq, M N; Bonn, G K

    2012-08-01

    The development of new high throughput methods based on different materials with chemical modifications for protein profiling of complex mixtures leads towards biomarkers; used particularly for early diagnosis of a disease. In this work, diamond-like carbon (DLC) is developed and optimized for serum protein profiling by matrix-assisted laser/desorption ionization mass spectrometry (MALDI-MS). This study is carried out in connection with a material-based approach, termed as material-enhanced laser desorption ionization mass spectrometry. DLC is selected as carrier surface which provides large surface to volume ratio and offers high sensitivity. DLC has a dual role of working as MALDI target while acting as an interface for protein profiling by specifically binding peptides and proteins out of serum samples. Serum constituents are bound through immobilized metal ion affinity chromatography (IMAC) functionality, created through glycidyl methacrylate polymerization under ultraviolet light followed by further derivatization with iminodiacetic acid and copper ion loading. Scanning electron microscopy highlights the morphological characteristics of DLC surface. It could be demonstrated that IMAC functionalized DLC coatings represent a powerful material in trapping biomolecules for their further analysis by MALDI-MS resulting in improved sensitivity, specificity and capacity in comparison to other protein-profiling methods.

  6. Hydrogen migration in diamond-like carbon films

    NASA Astrophysics Data System (ADS)

    Vainonen, E.; Likonen, J.; Ahlgren, T.; Haussalo, P.; Keinonen, J.; Wu, C. H.

    1997-10-01

    Properties of physical vapor deposited diamondlike carbon (DLC) films and the migration of hydrogen in H+ and 4He+ ion implanted and hydrogen co-deposited DLC films have been studied. Measurements utilizing Rutherford backscattering spectrometry showed that the films studied have an average mass density of 2.6±0.1 g/cm3. The bonding ratio sp3/sp2 is typically 70% measured with the electron spectroscopy for chemical analysis technique. Impurities and their depth distributions were deduced from the particle induced x-ray emission and secondary ion mass spectrometry (SIMS) measurements. Distributions of implanted and co-deposited hydrogen were measured by the nuclear resonance reaction 1H(15N,αγ)12C and SIMS. It was found that annealing behavior of implanted H in DLC has a diffusion like character. The obtained diffusion coefficients resulted in the activation energy of 2.0±0.1 eV. It was observed that in H co-deposited DLC films the temperature of H release varied between 950 and 1070 °C depending on the H concentration.

  7. Preparation and investigation of diamond-like carbon stripper foils by filtered cathodic vacuum arc

    NASA Astrophysics Data System (ADS)

    Fan, Qiwen; Du, Yinghui; Zhang, Rong; Xu, Guoji

    2013-04-01

    Thin diamond-like carbon (DLC) stripper foils ˜5 μg/cm2 in thickness were produced and evaluated as heavy-ion strippers for the Beijing HI-13 Tandem Accelerator. The DLC layers ˜4 μg/cm2 in thickness were produced by the filtered cathodic vacuum arc technology onto glass slides coated with betaine-saccharose as releasing agent, which were previously covered with evaporated carbon layers ˜1 μg/cm2 in thickness by the controlled ac arc-discharge method. Irradiation lifetimes of the DLC stripper foils were tested using the heavy-ion beams at the terminal of the Beijing HI-13 Tandem Accelerator, and compared with those of the standard carbon stripper foils made by the combined dc and ac arc-discharge method. The measurements indicate that the DLC stripper foils outlast the standard combined dc and ac arc-discharge carbon stripper foils by a factor of at least 13 and 4for the 197Au- (˜9 MeV, ˜1 μA) and 63Cu- (˜9 MeV, ˜1 μA) ion beams, respectively. The structure and properties of the DLC foils deposited onto silicon substrates by the filtered cathodic vacuum arc technology were also evaluated and analyzed by scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The scanning electron microscopy images show that the DLC foils contain hardly droplets through the double 90° filters. The X-ray photoelectron spectrum indicates that sp3 bonds of the DLC foils exceed 70%. The integral intensity ratio of the D peak to the G peak (ID/IG) measured by the Raman spectroscopy is0.78.

  8. Plasma and ion beam enhanced chemical vapour deposition of diamond and diamond-like carbon

    NASA Astrophysics Data System (ADS)

    Tang, Yongji

    WC-Co cutting tools are widely used in the machining industry. The application of diamond coatings on the surfaces of the tools would prolong the cutting lifetime and improves the manufacturing efficiency. However, direct chemical vapor deposition (CVD) of diamond coatings on WC-Co suffer from severe premature adhesion failure due to interfacial graphitization induced by the binder phase Co. In this research, a combination of hydrochloric acid (HCl) and hydrogen (H2) plasma pretreatments and a novel double interlayer of carbide forming element (CFE)/Al were developed to enhance diamond nucleation and adhesion. The results showed that both the pretreatments and interlayers were effective in forming continuous and adhesive nanocrystalline diamond coatings. The method is a promising replacement of the hazardous Murakami's regent currently used in WC-Co pretreatment with a more environmental friendly approach. Apart from coatings, diamond can be fabricated into other forms of nanostructures, such as nanotips. In this work, it was demonstrated that oriented diamond nanotip arrays can be fabricated by ion beam etching of as-grown CVD diamond. The orientation of diamond nanotips can be controlled by adjusting the direction of incident ion beam. This method overcomes the limits of other techniques in producing nanotip arrays on large areas with controlled orientation. Oriented diamond nano-tip arrays have been used to produce anisotropic frictional surface, which is successfully used in ultra-precision positioning systems. Diamond-like carbon (DLC) has many properties comparable to diamond. In this thesis, the preparation of alpha-C:H thin films by end-Hall (EH) ion source and the effects of ion energy and nitrogen doping on the microstructure and mechanical properties of the as-deposited thin films were investigated. The results have demonstrated that smooth and uniform alpha-C:H and alpha-C:H:N films with large area and reasonably high hardness and Young's modulus can be

  9. Diamond-like a-C:H coatings deposited in a non-self-sustained discharge with plasma cathode

    NASA Astrophysics Data System (ADS)

    Gavrilov, N. V.; Mamaev, A. S.; Kaĭigorodov, A. S.

    2009-01-01

    Hydrogenated amorphous carbon (a-C:H) coatings have been obtained by means of acetylene decomposition in a non-self-sustained periodic pulse discharge (2A, 50 kHz, 10 μs) with hollow cathode. The discharge operation was maintained by plasma cathode emission with grid stabilization based on dc glow discharge. Using the proposed method, it is possible to control the deposition conditions (total pressure of the Ar + C2H2 mixture, partial pressure of C2H2, ion current density, carbon ion energy) within broad limits, to apply a-C:H coatings onto large-area articles, and to perform deposition in one technological cycle with ion etching and ion implantation treatments aimed at improving the adhesion of coatings to substrates (Ti, Al, stainless steel, VK8 hard alloy) at temperatures below 150°C. Results of determining the deposition rate (1-8 μm), the nanohardness of coatings (up to 70 GPa), and the fraction of sp 3 bonds (25-70%) in the diamond-like coating material are presented.

  10. Characterisation of Diamond-Like Carbon (DLC) laser targets by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Haddock, D.; Parker, T.; Spindloe, C.; Tolley, M.

    2016-04-01

    The search for target materials suitable for High Power Laser Experiments at ultralow thicknesses (below ten nanometres) is ongoing. Diamond-Like Carbon is investigated as an answer for a low-Z material that can survive target chamber pump-down and laser prepulse. DLC was produced using Plasma-Enhanced Chemical Vapour Deposition, using with varying gas flow mixtures of argon and methane. The methane plasma deposits amorphous carbon onto the substrate and the argon plasma re-sputters the weakly bonded carbon leaving a high proportion of diamond-like bonding. Bonding natures were probed using Raman spectroscopy; analysis of the resulting spectrum showed that flow rates of 40sccm/60sccm methane to argon produced DLC films with a diamond-like (sp 3) content of ∼20%. Increasing the methane gas flow decreased this value to less than 5%. DLC foils were processed into laser targets by method of float off; using a sodium chloride release layer and lowering into water, this was then lifted onto an array of apertures allowing for laser irradiation of the material with no backing. DLC with 20% sp 3 content showed superior yield when compared to other materials such as metals and some plastics of the same thickness, with ∼70% of the target positions surviving the float off procedure at <10nm. As a result of this work DLC targets have been available for a number of experiments at the Central Laser Facility.

  11. Electrodeposition of diamond-like carbon films on titanium alloy using organic liquids: Corrosion and wear resistance

    NASA Astrophysics Data System (ADS)

    Falcade, Tiago; Shmitzhaus, Tobias Eduardo; dos Reis, Otávio Gomes; Vargas, André Luis Marin; Hübler, Roberto; Müller, Iduvirges Lourdes; de Fraga Malfatti, Célia

    2012-12-01

    Diamond-like carbon (DLC) films have been studied as coatings for corrosion protection and wear resistance because they have excellent chemical inertness in traditional corrosive environments, besides presenting a significant reduction in coefficient of friction. Diamond-like carbon (DLC) films obtained by electrochemical deposition techniques have attracted a lot of interest, regarding their potential in relation to the vapor phase deposition techniques. The electrochemical deposition techniques are carried out at room temperature and do not need vacuum system, making easier this way the technological transfer. At high electric fields, the organic molecules polarize and react on the electrode surface, forming carbon films. The aim of this work was to obtain DLC films onto Ti6Al4V substrate using as electrolyte: acetonitrile (ACN) and N,N-dimethylformamide (DMF). The films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman spectroscopy, potentiodynamic polarization and wear tests. The results show that these films can improve, significantly, the corrosion resistance of titanium and its alloys and their wear resistance.

  12. Characterization of diamond-like carbon thin film synthesized by RF atmospheric pressure plasma Ar/CH4 jet

    NASA Astrophysics Data System (ADS)

    Sohbatzadeh, Farshad; Safari, Reza; Etaati, G. Reza; Asadi, Eskandar; Mirzanejhad, Saeed; Hosseinnejad, Mohammad Taghi; Samadi, Omid; Bagheri, Hanieh

    2016-01-01

    The growth of diamond like carbon (DLC) on a Pyrex glass was investigated by a radio frequency (RF) atmospheric pressure plasma jet (APPJ). The plasma jet with capacitive configuration ran by a radio frequency power supply at 13.56 MHz. Alumina ceramic was used as dielectric barrier. Ar and CH4 were used in atmospheric pressure as carrier and precursor gases, respectively. Diamond like carbon thin films were deposited on Pyrex glass at substrate temperature and applied power of 130 °C and 250 Watts, respectively. Performing field emission scanning electron microscope (FE-SEM) and laser Raman spectroscopy analysis resulted in deposition rate and the ID/IG ratio of 21.31 nm/min and 0.47, respectively. The ID/IG ratio indicated that the coating possesses relative high sp3 content The optical emission spectroscopy (OES) diagnostic was applied to diagnose plasma jet species. Estimating electron temperature and density of the RF-APPJ resulted in 1.36 eV and 2.75 × 1014 cm-3 at the jet exit, respectively.

  13. Surface characterization and orientation interaction between diamond- like carbon layer structure and dimeric liquid crystals

    NASA Astrophysics Data System (ADS)

    Naradikian, H.; Petrov, M.; Katranchev, B.; Milenov, T.; Tinchev, S.

    2017-01-01

    Diamond-like carbon (DLC) and amorphous carbon films are very promising type of semiconductor materials. Depending on the hybridization sp2/sp3 ratio, the material’s band gap varies between 0.8 and 3 eV. Moreover carbon films possess different interesting for practice properties: comparable to the Silicon, Diamond like structure has 22-time better thermal conductivity etc. Here we present one type of implementation of such type nanostructure. That is one attempt for orientation of dimeric LC by using of pre-deposited DLC layer with different ratio of sp2/sp3 hybridized carbon content. It could be expected a pronounced π1-π2interaction between s and p orbital levels on the surface and the dimeric ring of LC. We present comparison of surface anchoring strengths of both orientation inter-surfaces DLC/dimeric LC and single wall carbon nanotubes (SWCNT)/dimeric LC. The mechanism of interaction of dimeric LC and activated surfaces with DLC or SWCNT will be discussed. In both cases we have π-π interaction, which in combination with hydrogen bonding, typical for the dimeric LCs, influence the LC alignment. The Raman spectroscopy data evidenced the presence of charge transfer between contacting hexagonal rings of DLC and the C = O groups of the LC molecules.

  14. Pulse widths dependence of programming and erasing behaviors for diamond like carbon based resistive switching memories

    NASA Astrophysics Data System (ADS)

    Xu, Jianlong; Xie, Dan; Zhang, Chenhui; Zhang, Xiaowen; Peng, Pinggang; Fu, Di; Qian, He; Ren, Tian-ling; Liu, Litian

    2014-10-01

    We report the influences of pulse widths on the programming and erasing characteristics of diamond-like carbon films based resistive random access memory. The device can be only programmed with pulses wider than 50 ns for SET operations when the pulse voltage is 1.2 V and erased with pulses narrower than 25 ns for RESET operations when the pulse voltage is 0.4 V. The formation, rupture, and re-growth of the conductive sp2-like graphitic filaments are proposed to be responsible for the resistive switching behaviors, based on which the pulse widths dependences on its programming and erasing properties can be further explained.

  15. Panel 2 - properties of diamond and diamond-like-carbon films

    SciTech Connect

    Blau, P.J.; Clausing, R.E.; Ajayi, O.O.; Liu, Y.Y.; Purohit, A.; Bartelt, P.F.; Baughman, R.H.; Bhushan, B.; Cooper, C.V.; Dugger, M.T.; Freedman, A.; Larsen-Basse, J.; McGuire, N.R.; Messier, R.F.; Noble, G.L.; Ostrowki, M.H.; Sartwell, B.D.; Wei, R.

    1993-01-01

    This panel attempted to identify and prioritize research and development needs in determining the physical, mechanical and chemical properties of diamond and diamond-like-carbon films (D/DLCF). Three specific goals were established. They were: (1) To identify problem areas which produce concern and require a better knowledge of D/DLCF properties. (2) To identify and prioritize key properties of D/DLCF to promote transportation applications. (3) To identify needs for improvement in properties-measurement methods. Each of these goals is addressed subsequently.

  16. The effect of diamond-like carbon coating on LiNi0.8Co0.15Al0.05O2 particles for all solid-state lithium-ion batteries based on Li2S-P2S5 glass-ceramics

    NASA Astrophysics Data System (ADS)

    Visbal, Heidy; Aihara, Yuichi; Ito, Seitaro; Watanabe, Taku; Park, Youngsin; Doo, Seokgwang

    2016-05-01

    There have been several reports on improvements of the performance of all solid-state battery using lithium metal oxide coatings on the cathode active material. However, the mechanism of the performance improvement remains unclear. To better understand the effect of the surface coating, we studied the impact of diamond-like carbon (DLC) coating on LiNi0.8Co0.15Al0.05O2 (NCA) by chemical vapor deposition (CVD). The DLC coated NCA showed good cycle ability and rate performance. This result is further supported by reduction of the interfacial resistance of the cathode and electrolyte observed in impedance spectroscopy. The DLC layer was analyzed by transmission electron microscopy electron energy loss spectroscopy (TEM-EELS). After 100 cycles the sample was analyzed by X-ray photo spectroscopy (XPS), and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). These analyses showed that the thickness of the coating layer was around 4 nm on average, acting to hinder the side reactions between the cathode particle and the solid electrolyte. The results of this study will provide useful insights for understanding the nature of the buffer layer for the cathode materials.

  17. Nanostructured titanium/diamond-like carbon multilayer films: deposition, characterization, and applications.

    PubMed

    Dwivedi, Neeraj; Kumar, Sushil; Malik, Hitendra K

    2011-11-01

    Titanium/diamond-like carbon multilayer (TDML) films were deposited using a hybrid system combining radio frequency (RF)-sputtering and RF-plasma enhanced chemical vapor deposition (PECVD) techniques under a varied number of Ti/diamond-like carbon (DLC) bilayers from 1 to 4, at high base pressure of 1 × 10(-3) Torr. The multilayer approach was used to create unique structures such as nanospheres and nanorods in TDML films, which is confirmed by scanning electron microscopy (SEM) analysis and explained by a hypothetical model. Surface composition was evaluated by X-ray photoelectron spectroscopy (XPS), whereas energy dispersive X-ray analysis (EDAX) and time-of-flight secondary ion mass spectrometer (ToF-SIMS) measurements were performed to investigate the bulk composition. X-ray diffraction (XRD) was used to evaluate the phase and crystallinity of the deposited TDML films. Residual stress in these films was found to be significantly low. These TDML films were found to have excellent nanomechanical properties with maximum hardness of 41.2 GPa. In addition, various nanomechanical parameters were calculated and correlated with each other. Owing to metallic interfacial layer of Ti in multilayer films, the optical properties, electrical properties, and photoluminescence were improved significantly. Due to versatile nanomechanical properties and biocompatibility of DLC and DLC based films, these TDML films may also find applications in biomedical science.

  18. Characterization of diamond-like carbon films by SEM, XRD and Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Pang, Hua; Wang, Xingquan; Zhang, Guling; Chen, Huan; Lv, Guohua; Yang, Size

    2010-08-01

    Diamond-like carbon films were deposited by electrolysis of a water-ethanol solution on Cu at low voltages (60-100 V) at 2 mm interelectrode separation. The films were characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD) and Raman spectroscopy. The films were found to be continuous and compact with uniform grain distribution. Raman spectroscopy analysis revealed two broad bands at ˜1350 and ˜1580 cm -1. The downshift of the G band of graphite is indicative of the presence of DLC. For XRD analysis, the three strong peaks located at 2 θ values of 43.2°, 74.06° and 89.9° can be identified with reflections form (1 1 1), (2 2 0) and (3 1 1) plane of diamond.

  19. Multilayers Diamond-Like Carbon Film with Germanium Buffer Layers by Pulsed Laser Deposition

    NASA Astrophysics Data System (ADS)

    Cheng, Y.; Lu, Y. M.; Guo, Y. L.; Huang, G. J.; Wang, S. Y.; Tian, F. T.

    Multilayer diamond-like carbon film with germanium buffer layers, which was composed of several thick DLC layers and thin germanium island “layers” and named as Ge-DLC film, was prepared on the germanium substrate by ultraviolet laser. The Ge-DLC film had almost same surface roughness as the pure DLC film. Hardness of the Ge-DLC film was above 48.1GPa, which was almost the same as that of pure DLC film. Meanwhile, compared to the pure DLC film, the critical load of Ge-DLC film on the germanium substrate increased from 81.6mN to 143.8mN. Moreover, Ge-DLC film on germanium substrates had no change after fastness tests. The results showed that Ge-DLC film not only kept high hardness but also had higher critical load than that of pure DLC film. Therefore, it could be used as practical protective films.

  20. Electron-beam induced diamond-like-carbon passivation of plasmonic devices

    NASA Astrophysics Data System (ADS)

    Balaur, Eugeniu; Sadatnajafi, Catherine; Langley, Daniel; Lin, Jiao; Kou, Shan Shan; Abbey, Brian

    2015-12-01

    Engineered materials with feature sizes on the order of a few nanometres offer the potential for producing metamaterials with properties which may differ significantly from their bulk counterpart. Here we describe the production of plasmonic colour filters using periodic arrays of nanoscale cross shaped apertures fabricated in optically opaque silver films. Due to its relatively low loss in the visible and near infrared range, silver is a popular choice for plasmonic devices, however it is also unstable in wet or even ambient conditions. Here we show that ultra-thin layers of Diamond-Like Carbon (DLC) can be used to prevent degradation due to oxidative stress, ageing and corrosion. We demonstrate that DLC effectively protects the sub-micron features which make up the plasmonic colour filter under both atmospheric conditions and accelerated aging using iodine gas. Through a systematic study we confirm that the nanometre thick DLC layers have no effect on the device functionality or performance.

  1. Cell viability and adhesion on diamond-like carbon films containing titanium dioxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Wachesk, C. C.; Pires, C. A. F.; Ramos, B. C.; Trava-Airoldi, V. J.; Lobo, A. O.; Pacheco-Soares, C.; Marciano, F. R.; Da-Silva, N. S.

    2013-02-01

    The combination of low friction, wear resistance, high hardness, biocompatibility and chemical inertness makes diamond-like carbon (DLC) films suitable in a numerous applications in biomedical engineering. The cell viability and adhesion of L929 mouse fibroblasts was investigated using two different colorimetric assays: (i) 2-(4,5-dimethyl-2-thiazolyl)-3,5-diphenyl-2H-tetrazolium bromide (MTT), and (ii) lactate dehydrogenase (LDH). The films were growth on 316L stainless steel substrates using plasma enhanced chemical vapor deposition technique from a dispersion of TiO2 nanopowder in hexane. The increasing concentration of TiO2 nanoparticles in DLC films enhanced the mitochondrial activity and decreases the LDH activity on these samples. Fluorescence and scanning electron microscopy corroborate the results. These experiments show the potential use of DLC and TiO2-DLC films in biomedical applications.

  2. Characterization of boron doped diamond-like carbon film by HRTEM

    NASA Astrophysics Data System (ADS)

    Li, X. J.; He, L. L.; Li, Y. S.; Yang, Q.; Hirose, A.

    2015-12-01

    Boron doped diamond-like carbon (B-DLC) film was synthesized on silicon (1 0 0) wafer by biased target ion beam deposition. High-resolution transmission electron microscopy (HRTEM) is employed to investigate the microstructure of the B-DLC thin film in cross-sectional observation. Many crystalline nanoparticles randomly dispersed and embedded in the amorphous matrix film are observed. Through chemical compositional analysis of the B-DLC film, some amount of O element is confirmed to be contained. And also, some nanoparticles with near zone axes are indexed, which are accordance with B2O phase. Therefore, the contained O element causing the B element oxidized is proposed, resulting in the formation of the nanoparticles. Our work indicates that in the B-DLC film a significant amount of the doped B element exists as boron suboxide nanoparticles.

  3. Engineering of the function of diamond-like carbon binding peptides through structural design.

    PubMed

    Gabryelczyk, Bartosz; Szilvay, Géza R; Singh, Vivek K; Mikkilä, Joona; Kostiainen, Mauri A; Koskinen, Jari; Linder, Markus B

    2015-02-09

    The use of phage display to select material-specific peptides provides a general route towards modification and functionalization of surfaces and interfaces. However, a rational structural engineering of the peptides for optimal affinity is typically not feasible because of insufficient structure-function understanding. Here, we investigate the influence of multivalency of diamond-like carbon (DLC) binding peptides on binding characteristics. We show that facile linking of peptides together using different lengths of spacers and multivalency leads to a tuning of affinity and kinetics. Notably, increased length of spacers in divalent systems led to significantly increased affinities. Making multimers influenced also kinetic aspects of surface competition. Additionally, the multivalent peptides were applied as surface functionalization components for a colloidal form of DLC. The work suggests the use of a set of linking systems to screen parameters for functional optimization of selected material-specific peptides.

  4. Theoretical Study of Diamond-Like Carbons and Nucleation of Diamond

    NASA Astrophysics Data System (ADS)

    Lee, Choon-Heung

    Different forms of amorphous carbon and hydrocarbons with varying elastic and optical properties, hardness, density and hydrogen content exist depending on the preparation technique. The structure can vary from graphitic to diamond -like, i.e., from mainly threefold coordinated to mainly four-fold coordinated. In order to study the properties of such materials, microscopic models must be developed. These studies include the modelling of crosslinked defective graphite, diamond nucleation along the graphite edges, and diamond-like carbons. Tamor's proposed structure for diamondlike carbon consists of crosslinked graphitic regions. We studied a concrete realization of this model in which the cross -links are produced by shortening the interplanar bond lengths. The model study was accomplished with a pure rhombohedral graphite cell. For this study we used a semi-empirical potential based on Tersoff's environment-dependent potential which contains angular terms. It is enhanced by a long-range potential which describes the interplanar interactions. We found a configuration corresponding to a local minimum. More general features such as the randomness of the distribution of cross-links are needed for a realistic model. A model study of diamond/graphite interfaces was motivated by recent observations by Li and Angus. They observed a significant enhancement of diamond nucleation on the graphite edge planes with the preferential orientation relationship: {0001} _{g} | {111 }_{d}, < 1120 >_{g} | < 101>_{d}. Two possible interface structures were studied using the Tersoff potential. We found that the models have comparable low interface energies even if they contain some dangling bonds. Moreover, lower interface energies were found when the dangling bonds of the non-bonded diamond layer were satisfied with hydrogen. We have proposed a growth mechanism based on this study. Finally, we constructed realistic models of dense amorphous carbon. The WWW (introduced earlier for a

  5. On interlayer stability and high-cycle simulator performance of diamond-like carbon layers for articulating joint replacements.

    PubMed

    Thorwarth, Kerstin; Thorwarth, Götz; Figi, Renato; Weisse, Bernhard; Stiefel, Michael; Hauert, Roland

    2014-06-11

    Diamond like carbon (DLC) coatings have been proven to be an excellent choice for wear reduction in many technical applications. However, for successful adaption to the orthopaedic field, layer performance, stability and adhesion in physiologically relevant setups are crucial and not consistently investigated. In vitro wear testing as well as adequate corrosion tests of interfaces and interlayers are of great importance to verify the long term stability of DLC coated load bearing implants in the human body. DLC coatings were deposited on articulating lumbar spinal disks made of CoCr28Mo6 biomedical implant alloy using a plasma-activated chemical vapor deposition (PACVD) process. As an adhesion promoting interlayer, tantalum films were deposited by magnetron sputtering. Wear tests of coated and uncoated implants were performed in physiological solution up to a maximum of 101 million articulation cycles with an amplitude of ±2° and -3/+6° in successive intervals at a preload of 1200 N. The implants were characterized by gravimetry, inductively coupled plasma optical emission spectrometry (ICP-OES) and cross section scanning electron microscopy (SEM) analysis. It is shown that DLC coated surfaces with uncontaminated tantalum interlayers perform very well and no corrosive or mechanical failure could be observed. This also holds true in tests featuring overload and third-body wear by cortical bone chips present in the bearing pairs. Regarding the interlayer tolerance towards interlayer contamination (oxygen), limits for initiation of potential failure modes were established. It was found that mechanical failure is the most critical aspect and this mode is hypothetically linked to the α-β tantalum phase switch induced by increasing oxygen levels as observed by X-ray diffraction (XRD). It is concluded that DLC coatings are a feasible candidate for near zero wear articulations on implants, potentially even surpassing the performance of ceramic vs. ceramic.

  6. On Interlayer Stability and High-Cycle Simulator Performance of Diamond-Like Carbon Layers for Articulating Joint Replacements

    PubMed Central

    Thorwarth, Kerstin; Thorwarth, Götz; Figi, Renato; Weisse, Bernhard; Stiefel, Michael; Hauert, Roland

    2014-01-01

    Diamond like carbon (DLC) coatings have been proven to be an excellent choice for wear reduction in many technical applications. However, for successful adaption to the orthopaedic field, layer performance, stability and adhesion in physiologically relevant setups are crucial and not consistently investigated. In vitro wear testing as well as adequate corrosion tests of interfaces and interlayers are of great importance to verify the long term stability of DLC coated load bearing implants in the human body. DLC coatings were deposited on articulating lumbar spinal disks made of CoCr28Mo6 biomedical implant alloy using a plasma-activated chemical vapor deposition (PACVD) process. As an adhesion promoting interlayer, tantalum films were deposited by magnetron sputtering. Wear tests of coated and uncoated implants were performed in physiological solution up to a maximum of 101 million articulation cycles with an amplitude of ±2° and −3/+6° in successive intervals at a preload of 1200 N. The implants were characterized by gravimetry, inductively coupled plasma optical emission spectrometry (ICP-OES) and cross section scanning electron microscopy (SEM) analysis. It is shown that DLC coated surfaces with uncontaminated tantalum interlayers perform very well and no corrosive or mechanical failure could be observed. This also holds true in tests featuring overload and third-body wear by cortical bone chips present in the bearing pairs. Regarding the interlayer tolerance towards interlayer contamination (oxygen), limits for initiation of potential failure modes were established. It was found that mechanical failure is the most critical aspect and this mode is hypothetically linked to the α-β tantalum phase switch induced by increasing oxygen levels as observed by X-ray diffraction (XRD). It is concluded that DLC coatings are a feasible candidate for near zero wear articulations on implants, potentially even surpassing the performance of ceramic vs. ceramic. PMID

  7. Electrochemical performance of porous diamond-like carbon electrodes for sensing hormones, neurotransmitters, and endocrine disruptors.

    PubMed

    Silva, Tiago A; Zanin, Hudson; May, Paul W; Corat, Evaldo J; Fatibello-Filho, Orlando

    2014-12-10

    Porous diamond-like carbon (DLC) electrodes have been prepared, and their electrochemical performance was explored. For electrode preparation, a thin DLC film was deposited onto a densely packed forest of highly porous, vertically aligned multiwalled carbon nanotubes (VACNT). DLC deposition caused the tips of the carbon nanotubes to clump together to form a microstructured surface with an enlarged surface area. DLC:VACNT electrodes show fast charge transfer, which is promising for several electrochemical applications, including electroanalysis. DLC:VACNT electrodes were applied to the determination of targeted molecules such as dopamine (DA) and epinephrine (EP), which are neurotransmitters/hormones, and acetaminophen (AC), an endocrine disruptor. Using simple and low-cost techniques, such as cyclic voltammetry, analytical curves in the concentration range from 10 to 100 μmol L(-1) were obtained and excellent analytical parameters achieved, including high analytical sensitivity, good response stability, and low limits of detection of 2.9, 4.5, and 2.3 μmol L(-1) for DA, EP, and AC, respectively.

  8. Dose-dependent cytotoxicity evaluation of graphite nanoparticles for diamond-like carbon film application on artificial joints.

    PubMed

    Liao, T T; Deng, Q Y; Wu, B J; Li, S S; Li, X; Wu, J; Leng, Y X; Guo, Y B; Huang, N

    2017-01-24

    While a diamond-like carbon (DLC)-coated joint prosthesis represents the implant of choice for total hip replacement in patients, it also leads to concern due to the cytotoxicity of wear debris in the form of graphite nanoparticles (GNs), ultimately limiting its clinical use. In this study, the cytotoxicity of various GN doses was evaluated. Mouse macrophages and osteoblasts were incubated with GNs (<30 nm diameter), followed by evaluation of cytotoxicity by means of assessing inflammatory cytokines, results of alkaline phosphatase assays, and related signaling protein expression. Cytotoxicity evaluation showed that cell viability decreased in a dose-dependent manner (10-100 μg ml(-1)), and steeply declined at GNs concentrations greater than 30 μg ml(-1). Noticeable cytotoxicity was observed as the GN dose exceeded this threshold due to upregulated receptor of activator of nuclear factor kB-ligand expression and downregulated osteoprotegerin expression. Meanwhile, activated macrophage morphology was observed as a result of the intense inflammatory response caused by the high doses of GNs (>30 μg ml(-1)), as observed by the increased release of TNF-α and IL-6. The results suggest that GNs had a significant dose-dependent cytotoxicity in vitro, with a lethal dose of 30 μg ml(-1) leading to dramatic increases in cytotoxicity. Our GN cytotoxicity evaluation indicates a safe level for wear debris-related arthropathy and could propel the clinical application of DLC-coated total hip prostheses.

  9. Superhard behaviour, low residual stress, and unique structure in diamond-like carbon films by simple bilayer approach

    SciTech Connect

    Dwivedi, Neeraj; Kumar, Sushil; Malik, Hitendra K.

    2012-07-15

    Simple bilayer approach is proposed for synthesizing hard and superhard diamond-like carbon (DLC) coatings with reduced residual stress. For this, M/DLC bilayer (M = Ti and Cu) structures are grown using hybrid system involving radio frequency (RF)-sputtering and RF-plasma enhanced chemical vapor deposition techniques. Ti/DLC bilayer deposited at negative self bias of 100 V shows superhard behaviour with hardness (H) as 49 GPa. Cu/DLC bilayer grown at self bias of 100 V exhibits hard behaviour with H as 22.8 GPa. The hardness of Ti/DLC (Cu/DLC) bilayer gets changed from superhard (hard) to hard (moderate hard) regime, when the self bias is raised to 300 V. Residual stress in Ti/DLC (Cu/DLC) bilayer is found to be significantly low that varies in the range of 1 GPa-1.65 GPa (0.8 GPa-1.6 GPa). The microstructure and morphology are studied by Raman spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). SEM and AFM pictures reveal the creation of nanostructured features in the deposited bilayers. Raman, SEM, and AFM analyses are correlated with the nano-mechanical properties. Owing to excellent nano-mechanical properties, these bilayers can find their direct industrial applications as hard and protective coatings.

  10. Structural and electrical characterization of boron-containing diamond-like carbon films deposited by femtosecond pulsed laser ablation

    NASA Astrophysics Data System (ADS)

    Sikora, A.; Berkesse, A.; Bourgeois, O.; Garden, J.-L.; Guerret-Piécourt, C.; Rouzaud, J.-N.; Loir, A.-S.; Garrelie, F.; Donnet, C.

    2009-10-01

    The present study investigates the influence of the incorporation of boron in Diamond-Like Carbon (DLC) films deposited by femtosecond laser ablation, on the structure and electrical properties of the coatings within the temperature range 70-300 K. Doping with boron has been performed by ablating alternatively graphite and boron targets. The film structure and composition have been highlighted by coupling Atomic Force Microscopy (AFM), Scanning Electron Microscopy equipped with a field emission gun (SEM-FEG) and High Resolution Transmission Electron Microscopy (HRTEM). Boron dilution ranges between 2 and 8% and appears as nanometer size clusters embedded in the DLC matrix. Typical resistivity values are 100 W cm for pure a-C films, down to few W cm for a-C:B films at room temperature. The resistance decreases exponentially when the temperature increases in the range 70-300 K. The results are discussed considering the classical model of hopping conduction in thin films. Some coatings show temperature coefficients of resistance (TCR) as high as 3.85%. TCRs decrease when the doping increases. Such high values of TCR may have interests in the use of these films as thermometer elements in micro and nanodevices.

  11. Composition and properties of the so-called 'diamond-like' amorphous carbon films

    NASA Technical Reports Server (NTRS)

    Angus, J. C.; Stultz, J. E.; Shiller, P. J.; Macdonald, J. R.; Mirtich, M. J.

    1984-01-01

    The composition of amorphous 'diamond-like' films made by direct low energy ion beam deposition, R.F. discharge and sputtering was determined by nuclear reaction analysis, IR spectroscopy and microcombustion chemical analysis. The nuclear reaction analysis showed very similar hydrogen depth profiles for all three types of samples. The atomic ratio of hydrogen to carbon was approximately 0.2 at the film surface and rose to approximately 1.0 at a depth of 500 A. The integrated intensity of the C-H stretching band at about 2900 per cm indicates that the amount of chemically bonded hydrogen is less than the total hydrogen content. Combustion analysis confirmed the overall atomic ratio of hydrogen to carbon determined by nuclear reaction analysis. The chemical state of the non-bonded hydrogen was not determined; however, the effective diffusion coefficient computed from the hydrogen depth profile was extremely low. This indicates either that the films are exceedingly impermeable or that the non-bonded hydrogen requires an additional activated step to leave the films, e.g., desorption or chemical reaction.

  12. Structural and mechanical properties of diamond-like carbon films deposited by direct current magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Broitman, E.; Hellgren, N.; Czigány, Zs.; Twesten, R. D.; Luning, J.; Petrov, I.; Hultman, L.; Holloway, B. C.

    2003-07-01

    The microstructure, morphology, and mechanical properties of diamond-like carbon (DLC) films deposited by direct current magnetron sputtering were investigated for microelectromechanical systems applications. Film properties were found to vary markedly with the ion energy (Eion) and ion-to-carbon flux ratio (Jion/JC). Cross-sectional high-resolution transmission electron microscopy revealed an amorphous microstructure. However, the presence of nanometer-sized domains at Eion~85 eV was detected. Film stresses, σ, which were compressive in all cases, ranged from 0.5 to 3.5 GPa and depended on the flux ratio as well as ion energy. The hardness (H), Young's moduli (ɛ), and elastic recovery (R) increased with Eion to maximum values of H=27 GPa, ɛ=250 GPa, and R=68% at Eion=85 eV and Jion/JC=4.4. However, near edge x-ray absorption fine structure and electron energy-loss spectrum analysis showed that the sp2/sp3 content of the films does not change with Eion or Jion/JC. The measured change in mechanical properties without a corresponding change in sp2/sp3 ratio is not consistent with any previously published models. We suggest that, in the ranges 5 eV <=Eion<=85 eV and 1.1 <=Jion/JC<=6.8, the presence of defective graphite formed by subplanted C and Ar atoms has the dominant influence on the mechanical properties of DLC films.

  13. Deposition of Fluorinated Diamond-Like-Carbon Films by Exposure of Electrothermal Pulsed Plasmas

    NASA Astrophysics Data System (ADS)

    Kimura, Takashi; Iida, Masayasu

    2011-08-01

    Thin amorphous carbon films are deposited on silicon substrates by exposure to pulsed plasmas where the feed gas is mainly generated from the ablation of an insulator. An electrothermal pulsed plasma thruster with a discharge room in an insulator rod is used as the pulsed plasma for the ablation of the insulator, and the material of the insulator rod is poly(tetrafluoroethylene) (PTFE). The pulsed plasma, in which the estimated electron density is on the order of 1022-1023 m-3, is generated by the stored energy in the capacitor. The deposition rate, which depends on the stored energy, is lower than 1 nm per pulse in our experiment. The maximum hardness measured using a nanoindenter is about 7 GPa at a stored energy of about 2.7 J, beyond which the hardness of the films decreases with the increase in stored energy. Raman spectroscopy is also carried out to examine the formation of fluorinated diamond-like carbon films. In addition, the influence of dilution gas on the properties of the deposited films is also investigated.

  14. Fabrication and characterization of freestanding ultrathin diamond-like carbon targets for high-intensity laser applications

    NASA Astrophysics Data System (ADS)

    Ho, Timothy T.; Gupta, Manisha; Chowdhury, Fatema Rezwana; Chen, Zhijiang; Tsui, Ying Yin

    2013-12-01

    Here, we report the fabrication of diamond-like carbon (DLC) thin films using pulsed laser deposition (PLD). PLD is a well-established technique for deposition of high-quality DLC thin films. Carbon tape target was ablated using a KrF (248 nm, 25 ns, 20 Hz) excimer laser to deposit DLC films on soap-coated substrates. A laser fluence between 8.5 and 14 J/cm2 and a target to substrate distance of 10 cm was used. These films were then released from substrates to obtain freestanding DLC thin foils. Foil thicknesses from 20 to 200 nm were deposited using this technique to obtain freestanding targets of up to 1-inch square area. Typically, 100-nm-thick freestanding DLC films were characterized using different techniques such as AFM, XPS, and nano-indentation. AFM was used to obtain the film surface roughness of 9 nm rms of the released film. XPS was utilized to obtain 74 % sp2, 23 % sp3, and 3 % C-O bond components. Nano-indentation was used to characterize the film hardness of 10 GPa and Young's modulus of 110 GPa. Damage threshold properties of the DLC foils were studied (1,064 nm, 6 ns) and found to be 7 × 1010 W/cm2 peak intensity for our best ultrathin DLC foils.

  15. Synthesis of flat sticky hydrophobic carbon diamond-like films using atmospheric pressure Ar/CH4 dielectric barrier discharge

    NASA Astrophysics Data System (ADS)

    Rincón, R.; Hendaoui, A.; de Matos, J.; Chaker, M.

    2016-06-01

    An Ar/CH4 atmospheric pressure dielectric barrier discharge (AP-DBD) was used to synthesize sticky hydrophobic diamond-like carbon (DLC) films on glass surface. The film is formed with plasma treatment duration shorter than 30 s, and water contact angles larger than 90° together with contact angle hysteresis larger than 10° can be achieved. According to Fourier transform infrared spectroscopy and atomic force microscopy analysis, hydrocarbon functional groups are created on the glass substrate, producing coatings with low surface energy (˜35 mJ m-2) with no modification of the surface roughness. To infer the plasma processes leading to the formation of low energy DLC surfaces, optical emission spectroscopy was used. From the results, a direct relationship between the CH species present in the plasma and the carbon concentration in the hydrophobic layer was found, which suggests that the CH species are the precursors of DLC film growth. Additionally, the plasma gas temperature was measured to be below 350 K which highlights the suitability of using AP-DBD to treat thermo-sensitive surfaces.

  16. Conditions for forming composite carbon nanotube-diamond like carbon material that retain the good properties of both materials

    SciTech Connect

    Ren, Wei Avchaciov, Konstantin; Nordlund, Kai; Iyer, Ajai; Koskinen, Jari; Kaskela, Antti; Kauppinen, Esko I.

    2015-11-21

    Carbon nanotubes are of wide interest due to their excellent properties such as tensile strength and electrical and thermal conductivity, but are not, when placed alone on a substrate, well resistant to mechanical wear. Diamond-like carbon (DLC), on the other hand, is widely used in applications due to its very good wear resistance. Combining the two materials could provide a very durable pure carbon nanomaterial enabling to benefit from the best properties of both carbon allotropes. However, the synthesis of high-quality diamond-like carbon uses energetic plasmas, which can damage the nanotubes. From previous works it is neither clear whether the quality of the tubes remains good after DLC deposition, nor whether the DLC above the tubes retains the high sp{sup 3} bonding fraction. In this work, we use experiments and classical molecular dynamics simulations to study the mechanisms of DLC formation on various carbon nanotube compositions. The results show that high-sp{sup 3}-content DLC can be formed provided the deposition conditions allow for sidewards pressure to form from a substrate close beneath the tubes. Under optimal DLC formation energies of around 40–70 eV, the top two nanotube atom layers are fully destroyed by the plasma deposition, but layers below this can retain their structural integrity.

  17. Conditions for forming composite carbon nanotube-diamond like carbon material that retain the good properties of both materials

    NASA Astrophysics Data System (ADS)

    Ren, Wei; Iyer, Ajai; Koskinen, Jari; Kaskela, Antti; Kauppinen, Esko I.; Avchaciov, Konstantin; Nordlund, Kai

    2015-11-01

    Carbon nanotubes are of wide interest due to their excellent properties such as tensile strength and electrical and thermal conductivity, but are not, when placed alone on a substrate, well resistant to mechanical wear. Diamond-like carbon (DLC), on the other hand, is widely used in applications due to its very good wear resistance. Combining the two materials could provide a very durable pure carbon nanomaterial enabling to benefit from the best properties of both carbon allotropes. However, the synthesis of high-quality diamond-like carbon uses energetic plasmas, which can damage the nanotubes. From previous works it is neither clear whether the quality of the tubes remains good after DLC deposition, nor whether the DLC above the tubes retains the high sp3 bonding fraction. In this work, we use experiments and classical molecular dynamics simulations to study the mechanisms of DLC formation on various carbon nanotube compositions. The results show that high-sp3-content DLC can be formed provided the deposition conditions allow for sidewards pressure to form from a substrate close beneath the tubes. Under optimal DLC formation energies of around 40-70 eV, the top two nanotube atom layers are fully destroyed by the plasma deposition, but layers below this can retain their structural integrity.

  18. Collision cascades enhanced hydrogen redistribution in cobalt implanted hydrogenated diamond-like carbon films

    NASA Astrophysics Data System (ADS)

    Gupta, P.; Becker, H.-W.; Williams, G. V. M.; Hübner, R.; Heinig, K.-H.; Markwitz, A.

    2017-03-01

    Hydrogenated diamond-like carbon films produced by C3H6 deposition at 5 kV and implanted at room temperature with 30 keV Co atoms to 12 at.% show not only a bimodal distribution of Co atoms but also a massive redistribution of hydrogen in the films. Resonant nuclear reaction analysis was used to measure the hydrogen depth profiles (15N-method). Depletion of hydrogen near the surface was measured to be as low as 7 at.% followed by hydrogen accumulation from 27 to 35 at.%. A model is proposed considering the thermal energy deposited by collision cascade for thermal insulators. In this model, sufficient energy is provided for dissociated hydrogen to diffuse out of the sample from the surface and diffuse into the sample towards the interface which is however limited by the range of the incoming Co ions. At a hydrogen concentration of ∼35 at.%, the concentration gradient of the mobile unbounded hydrogen atoms is neutralised effectively stopping diffusion towards the interface. The results point towards new routes of controlling the composition and distribution of elements at the nanoscale within a base matrix without using any heat treatment methods. Exploring these opportunities can lead to a new horizon of materials and device engineering needed for enabling advanced technologies and applications.

  19. Structural modifications of diamond like carbon films induced by MeV nitrogen ion irradiation

    NASA Astrophysics Data System (ADS)

    Mathew, S.; Bhatta, U. M.; Islam, A. K. M. Maidul; Mukherjee, M.; Ray, N. R.; Dev, B. N.

    2009-02-01

    Diamond-like carbon (DLC) films were deposited on Si(1 0 0) substrates using plasma deposition technique. The deposited films were irradiated using 2 MeV N + ions at fluences of 1×1014, 1×1015 and 5×1015 ions/cm 2. Samples have been characterized by using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM). Analysis of Raman spectra shows a gradual shift of both D and G band peaks towards higher frequencies along with an increase of the intensity ratio, I(D)/ I(G), with increasing ion fluence in irradiation. These results are consistent with an increase of sp 2 bonding. XPS results also show a monotonic increase of sp 2/sp 3 hybridization ratio with increasing ion fluence. Plan view TEM images show the formation of clusters in the irradiated DLC films. HRTEM micrographs from the samples irradiated at a fluence of 5×1015 ions/cm 2 show the lattice image with an average interplanar spacing of 0.34 nm, revealing that the clusters are graphite clusters. The crystallographic planes in these clusters are somewhat distorted compared to the perfect graphite structure.

  20. Annealing Effects on Structure and Optical Properties of Diamond-Like Carbon Films Containing Silver.

    PubMed

    Meškinis, Šarūnas; Čiegis, Arvydas; Vasiliauskas, Andrius; Šlapikas, Kęstutis; Gudaitis, Rimantas; Yaremchuk, Iryna; Fitio, Volodymyr; Bobitski, Yaroslav; Tamulevičius, Sigitas

    2016-12-01

    In the present study, diamond-like carbon films with embedded Ag nanoparticles (DLC:Ag) were deposited by reactive magnetron sputtering. Structure of the films was investigated by Raman scattering spectroscopy. Atomic force microscopy was used to define thickness of DLC:Ag films as well as to study the surface morphology and size distribution of Ag nanoparticles. Optical absorbance and reflectance spectra of the films were studied in the 180-1100-nm range. Air annealing effects on structure and optical properties of the DLC:Ag were investigated. Annealing temperatures were varied in the 180-400 °C range. Changes of size and shape of the Ag nanoclusters took place due to agglomeration. It was found that air annealing of DLC:Ag films can result in graphitization following destruction of the DLC matrix. Additional activation of surface-enhanced Raman scattering (SERS) effect in DLC:Ag films can be achieved by properly selecting annealing conditions. Annealing resulted in blueshift as well as significant narrowing of the plasmonic absorbance and reflectance peaks. Moreover, quadrupole surface plasmon resonance peaks appeared. Modeling of absorption spectra of the nanoclusters depending on the shape and surrounding media has been carried out.

  1. Influence of Third Particle on the Tribological Behaviors of Diamond-like Carbon Films

    PubMed Central

    Bai, Lichun; Srikanth, Narasimalu; Kang, Guozheng; Zhou, Kun

    2016-01-01

    Tribological mechanisms of diamond-like carbon (DLC) films in a sand-dust environment are commonly unclear due to the complicated three-body abrasion caused by sand particles. This study investigates the three-body abrasion of the DLC film via molecular dynamics simulations. The influence factors such as the load, velocity, shape of the particle and its size are considered. It has been found that the friction and wear of the DLC film are determined by adhesion at a small load but dominated by both adhesion and plowing at a large load. A high velocity can increase the friction of the DLC film but decrease its wear, due to the response of its networks to a high strain rate indicated by such velocity. The shape of the particle highly affects its movement mode and thus changes the friction and wear of the DLC film. It is found that a small-sized particle can increase the friction and wear of the DLC film by enhancing plowing. These unique tribological mechanisms of the DLC film can help to promote its wide applications in a sand-dust environment. PMID:27917916

  2. Influence of Third Particle on the Tribological Behaviors of Diamond-like Carbon Films

    NASA Astrophysics Data System (ADS)

    Bai, Lichun; Srikanth, Narasimalu; Kang, Guozheng; Zhou, Kun

    2016-12-01

    Tribological mechanisms of diamond-like carbon (DLC) films in a sand-dust environment are commonly unclear due to the complicated three-body abrasion caused by sand particles. This study investigates the three-body abrasion of the DLC film via molecular dynamics simulations. The influence factors such as the load, velocity, shape of the particle and its size are considered. It has been found that the friction and wear of the DLC film are determined by adhesion at a small load but dominated by both adhesion and plowing at a large load. A high velocity can increase the friction of the DLC film but decrease its wear, due to the response of its networks to a high strain rate indicated by such velocity. The shape of the particle highly affects its movement mode and thus changes the friction and wear of the DLC film. It is found that a small-sized particle can increase the friction and wear of the DLC film by enhancing plowing. These unique tribological mechanisms of the DLC film can help to promote its wide applications in a sand-dust environment.

  3. Functionalization of Hydrogen-free Diamond-like Carbon Films using Open-air Dielectric Barrier Discharge Atmospheric Plasma Treatments

    SciTech Connect

    Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Instituto de Materiales de Madrid, C.S.I.C., Cantoblanco, 28049 Madrid, Spain; Instituto de Quimica-Fisica"Rocasolano"C.S.I.C., 28006 Madrid, Spain; Mahasarakham University, Mahasarakham 44150, Thailand; CASTI, CNR-INFM Regional Laboratory, L'Aquila 67100, Italy; SUNY Upstate Medical University, Syracuse, NY 13210, USA; Endrino, Jose; Endrino, J. L.; Marco, J. F.; Poolcharuansin, P.; Phani, A.R.; Allen, M.; Albella, J. M.; Anders, A.

    2007-12-28

    A dielectric barrier discharge (DBD) technique has been employed to produce uniform atmospheric plasmas of He and N2 gas mixtures in open air in order to functionalize the surface of filtered-arc deposited hydrogen-free diamond-like carbon (DLC) films. XPS measurements were carried out on both untreated and He/N2 DBD plasma treated DLC surfaces. Chemical states of the C 1s and N 1s peaks were collected and used to characterize the surface bonds. Contact angle measurements were also used to record the short- and long-term variations in wettability of treated and untreated DLC. In addition, cell viability tests were performed to determine the influence of various He/N2 atmospheric plasma treatments on the attachment of osteoblast MC3T3 cells. Current evidence shows the feasibility of atmospheric plasmas in producing long-lasting variations in the surface bonding and surface energy of hydrogen-free DLC and consequently the potential for this technique in the functionalization of DLC coated devices.

  4. A planar diamond-like carbon nanostructure for a low-voltage field emission cathode with a developed surface

    NASA Astrophysics Data System (ADS)

    Aban'shin, N. P.; Avetisyan, Yu. A.; Akchurin, G. G.; Loginov, A. P.; Morev, S. P.; Mosiyash, D. S.; Yakunin, A. N.

    2016-05-01

    Issues pertaining to the effective solution of problems related to the creation of durable low-voltage field emission cathodes with developed working surface and high density of emission current are considered. Results of practical implementation of the concept of multielectrode field emission planar nanostructures based on diamond-like carbon are presented. High average current density (0.1-0.3 A cm-2) is ensured by the formation of a controlled zone of electrostatic field localization at the planar-edge structure. The working life of cathode samples reaches 700-3000 h due to several positive factors, such as the stabilizing properties of a diamond-like carbon film, protection of the emitter from ion bombardment, use of a system of ballast resistors, and low-voltage operation of submicron interelectrode gaps.

  5. In vitro Cyto and Blood Compatibility of Titanium Containing Diamond-Like Carbon Prepared by Hybrid Sputtering Method

    NASA Astrophysics Data System (ADS)

    Krishnasamy Navaneetha, Pandiyaraj; Jan, Heeg; Andreas, Lampka; Fabian, Junge; Torsten, Barfels; Marion, Wienecke; Young, Ha Rhee; Hyoung, Woo Kim

    2012-09-01

    In recent years, diamond-like carbon films (DLC) have been given more attention in research in the biomedical industry due to their potential application as surface coating on biomedical materials such as metals and polymer substrates. There are many ways to prepare metal containing DLC films deposited on polymeric film substrates, such as coatings from carbonaceous precursors and some means that incorporate other elements. In this study, we investigated both the surface and biocompatible properties of titanium containing DLC (Ti-DLC) films. The Ti-DLC films were prepared on the surface of poly (ethylene terephthalate) (PET) film as a function of the deposition power level using reactive sputtering technique. The films' hydrophilicity was studied by contact angle and surface energy tests. Their surface morphology was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Their elemental chemical composition was analyzed using energy dispersive X-spectra (EDX) and X-ray photoelectron spectroscopy (XPS). Their blood and cell compatibility was studied by in vitro tests, including tests on platelet adhesion, thrombus formation, whole blood clotting time and osteoblast cell compatibility. Significant changes in the morphological and chemical composition of the Ti-DLC films were observed and found to be a function of the deposition level. These morphological and chemical changes reduced the interfacial tension between Ti-DLC and blood proteins as well as resisted the adhesion and activation of platelets on the surface of the Ti-DLC films. The cell compatibility results exhibited significant growth of osteoblast cells on the surface of Ti incorporated DLC film compared with that of DLC film surface.

  6. Improvement of radiation stability of semi-insulating gallium arsenide crystals by deposition of diamond-like carbon films

    NASA Astrophysics Data System (ADS)

    Klyui, N. I.; Lozinskii, V. B.; Liptuga, A. I.; Izotov, V. Yu.; Han, Wei; Liu, Bingbing

    2016-12-01

    We studied the properties of optical elements for the IR spectral range based on semi-insulating gallium arsenide (SI-GaAs) and antireflecting diamond-like carbon films (DLCF). Particular attention has been paid to the effect of penetrating γ-radiation on transmission of the developed optical elements. A Co60 source and step-by-step gaining of γ-irradiation dose were used for treatment of both an initial SI-GaAs crystal and DLCF/SI-GaAs structures. It was shown that DLCF deposition essentially increases degradation resistance of the SI-GaAs-based optical elements to γ-radiation. Particularly, the transmittance of the DLCF/SI-GaAs structure after γ-irradiation with a dose 9ṡ104 Gy even exceeds that of initial structures. The possible mechanism that explains the effect of γ-radiation on the SI-GaAs crystals and the DLCF/SI-GaAs structures at different irradiation doses was proposed. The effect of small doses is responsible for non-monotonic transmission changes in both SI-GaAs crystals and DLCF/SI-GaAs structures. At further increasing the γ-irradiation dose, the variation of properties of both DLCF and SI-GaAs crystal influences on the transmission of DLCF/SI-GaAs system. At high γ-irradiation dose 1.4ṡ105 Gy, passivation of radiation defects in the SI-GaAs bulk by hydrogen diffused from DLCF leads to increasing the degradation resistance of the SI-GaAs crystals coated with DLCF as compared with the crystals without DLCF.

  7. Effect of deposition condition and post growth irradiation treatment on the physical properties of diamond-like carbon films

    SciTech Connect

    Semenovich, V.A.; Dub, S.N.; Klyui, N.I.

    1995-12-31

    Effect of the RF (13.56 MHz) amplitude (Usa) bias voltage on the physical properties of the films has been examined. Relation between the properties of the films and growth conditions were obtained. Bias voltage and gas composition have a marked influence on the properties of prepared films. Nitrogen implantation of diamond-like carbon (DLC) films improves essentially mechanical properties (increasing of the hardness and Young`s modulus more than two times), which correlates with changes of the optical properties, namely, decreasing of optical band gap and increasing of refractive index of the implanted layer.

  8. Enhanced field electron emission from aligned diamond-like carbon nanorod arrays prepared by reactive ion beam etching

    NASA Astrophysics Data System (ADS)

    Zhao, Yong; Qin, Shi-Qiao; Zhang, Xue-Ao; Chang, Sheng-Li; Li, Hui-Hui; Yuan, Ji-Ren

    2016-05-01

    Homogeneous diamond-like carbon (DLC) films were deposited on Si supports by a pulsed filtered cathodic vacuum arc deposition system. Using DLC films masked by Ni nanoparticles as precursors, highly aligned diamond-like carbon nanorod (DLCNR) arrays were fabricated by the etching of inductively coupled radio frequency oxygen plasma. The as-prepared DLCNR arrays exhibit excellent field emission properties with a low turn-on field of 2.005 V μm-1 and a threshold field of 4.312 V μm-1, respectively. Raman spectroscopy and x-ray photoelectron spectroscopy were employed to determine the chemical bonding structural change of DLC films before and after etching. It is confirmed that DLC films have good connection with Si supports via the formation of the SiC phase, and larger conductive sp2 domains are formed in the as-etched DLC films, which play essential roles in the enhanced field emission properties for DLCNR arrays.

  9. Ultrathin diamond-like carbon films deposited by filtered carbon vacuum arcs

    SciTech Connect

    Anders, Andre; Fong, Walton; Kulkarni, Ashok; Ryan, Francis W.; Bhatia, C. Singh

    2001-07-13

    Ultrathin (< 5 nm) hard carbon films are of great interest to the magnetic storage industry as the areal density approaches 100 Gbit/in{sup 2}. These films are used as overcoats to protect the magnetic layers on disk media and the active elements of the read-write slider. Tetrahedral amorphous carbon films can be produced by filtered cathodic arc deposition, but the films will only be accepted by the storage industry only if the ''macroparticle'' issue has been solved. Better plasma filters have been developed over recent years. Emphasis is put on the promising twist filter system - a compact, open structure that operates with pulsed arcs and high magnetic field. Based on corrosion tests it is shown that the macroparticle reduction by the twist filter is satisfactory for this demanding application, while plasma throughput is very high. Ultrathin hard carbon films have been synthesized using S-filter and twist filter systems. Film properties such as hardness, elastic modulus, wear, and corrosion resistance have been tested.

  10. Tuning properties of long-period gratings by plasma post-processing of their diamond-like carbon nano-overlays

    NASA Astrophysics Data System (ADS)

    Smietana, M.; Koba, M.; Mikulic, P.; Bock, W. J.

    2014-11-01

    This work presents an application of reactive ion etching (RIE) for effective tuning of spectral response and the refractive index (RI) sensitivity of diamond-like carbon (DLC) nano-coated long-period gratings (LPGs). When oxygen plasma is applied the technique allows for an efficient and well controlled etching of hard and chemically resistant DLC films deposited on optical fibers. We show that optical properties of DLC, especially its refractive index, strongly depend on thickness of the film when it is thinner than 150 nm. The effect of DLC nano-coating deposition and etching on spectral properties of the LPGs is discussed. We have correlated the DLC properties with the shift of the LPG resonance wavelength and have found that both deposition and etching processes took place less effectively than on the electrode when the LPG sample was held above the electrode in the plasma reactor. An advantage of plasma-based etching is a capability for post-processing of the nano-coated structures with a good precision, as well as cleaning the samples and their re-coating according to requested needs. Moreover, the application of RIE allows for post-fabrication tuning of RI sensitivity of the DLC nano-coated LPGs.

  11. In situ observation of atomic hydrogen etching on diamond-like carbon films produced by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Cheng, C.-L.; Chia, C.-T.; Chiu, C.-C.; Wu, C.-C.; Cheng, H.-F.; Lin, I.-N.

    2001-04-01

    Atomic hydrogen etching on the pulsed laser deposited (PLD) diamond-like carbon (DLC) films were examined in situ by using Raman spectroscopy. Thermal annealing of the as-prepared DLC films was found to alter the D-band (˜1355 cm -1) and G-band (˜1582 cm -1) from unresolved features at room temperature to clearly separated bands at above 500°C, indicating graphitization of the films. The presence of atomic hydrogen retards graphitization at temperatures lower than 500°C, presumably because reactive atomic hydrogen formed sp 3-bonding carbons which prevented graphitization at below 500°C, while at above 500°C, the hydrogen etches away disordered structure of the DLC film as the intensity changes of the D-bands demonstrate.

  12. Structural characteristics of surface-functionalized nitrogen-doped diamond-like carbon films and effective adjustment to cell attachment

    NASA Astrophysics Data System (ADS)

    Liu, Ai-Ping; Liu, Min; Yu, Jian-Can; Qian, Guo-Dong; Tang, Wei-Hua

    2015-05-01

    Nitrogen-doped diamond-like carbon (DLC:N) films prepared by the filtered cathodic vacuum arc technology are functionalized with various chemical molecules including dopamine (DA), 3-Aminobenzeneboronic acid (APBA), and adenosine triphosphate (ATP), and the impacts of surface functionalities on the surface morphologies, compositions, microstructures, and cell compatibility of the DLC:N films are systematically investigated. We demonstrate that the surface groups of DLC:N have a significant effect on the surface and structural properties of the film. The activity of PC12 cells depends on the particular type of surface functional groups of DLC:N films regardless of surface roughness and wettability. Our research offers a novel way for designing functionalized carbon films as tailorable substrates for biosensors and biomedical engineering applications. Project supported by the National Natural Science Foundation of China (Grant Nos. 51272237, 51272231, and 51010002) and the China Postdoctoral Science Foundation (Grant Nos. 2012M520063, 2013T60587, and Bsh1201016).

  13. Biocompatibility and mechanical properties of diamond-like coatings on cobalt-chromium-molybdenum steel and titanium-aluminum-vanadium biomedical alloys.

    PubMed

    Hinüber, C; Kleemann, C; Friederichs, R J; Haubold, L; Scheibe, H J; Schuelke, T; Boehlert, C; Baumann, M J

    2010-11-01

    Diamond-like carbon (DLC) films are favored for wear components because of diamond-like hardness, low friction, low wear, and high corrosion resistance (Schultz et al., Mat-wiss u Werkstofftech 2004;35:924-928; Lappalainen et al., J Biomed Mater Res B Appl Biomater 2003;66B:410-413; Tiainen, Diam Relat Mater 2001;10:153-160). Several studies have demonstrated their inertness, nontoxicity, and the biocompatibility, which has led to interest among manufacturers of surgical implants (Allen et al., J Biomed Mater Res B Appl Biomater 2001;58:319-328; Uzumaki et al., Diam Relat Mater 2006;15:982-988; Hauert, Diam Relat Mater 2003;12:583-589; Grill, Diam Relat Mater 2003;12:166-170). In this study, hydrogen-free amorphous, tetrahedrally bonded DLC films (ta-C) were deposited at low temperatures by physical vapor deposition on medical grade Co28Cr6Mo steel and the titanium alloy Ti6Al4V (Scheibe et al., Surf Coat Tech 1996;85:209-214). The mechanical performance of the ta-C was characterized by measuring its surface roughness, contact angle, adhesion, and wear behavior, whereas the biocompatibility was assessed by osteoblast (OB) attachment and cell viability via Live/Dead assay. There was no statistical difference found in the wettability as measured by contact angle measurements for the ta-C coated and the uncoated samples of either Co28Cr6Mo or Ti6Al4V. Rockwell C indentation and dynamic scratch testing on 2-10 μm thick ta-C films on Co28Cr6Mo substrates showed excellent adhesion with HF1 grade and up to 48 N for the critical load L(C2) during scratch testing. The ta-C coating reduced the wear from 3.5 × 10(-5) mm(3)/Nm for an uncoated control sample (uncoated Co28Cr6Mo against uncoated stainless steel) to 1.1 × 10(-7) mm(3)/Nm (coated Co28Cr6Mo against uncoated stainless steel) in reciprocating pin-on-disk testing. The lowest wear factor of 3.9 × 10(-10) mm(3)/Nm was measured using a ta-C coated steel ball running against a ta-C coated and polished Co28Cr6Mo disk

  14. On the nature of the coefficient of friction of diamond-like carbon films deposited on rubber

    NASA Astrophysics Data System (ADS)

    Martinez-Martinez, D.; van der Pal, J. P.; Schenkel, M.; Shaha, K. P.; Pei, Y. T.; De Hosson, J. Th. M.

    2012-06-01

    In this paper, the nature of the coefficient of friction (CoF) of diamond-like carbon (DLC)-protected rubbers is studied. The relative importance of the viscoelastic and adhesive contributions to the overall friction is evaluated experimentally by modifying the contact load and the adhesive strength between the surface and the counterpart. The results indicate that the increase of CoF during the tribotests under non-lubricated conditions is caused by the increase of the adhesive contribution to friction motivated by the growth of the contact area during the test. In the case of oil lubricating condition, the adhesive force is minimized and the CoF is observed to decrease during the tribotest. This is caused by the reduction of the viscoelastic contribution due to the variation of the shape of the contact area. The role of the microstructure of the DLC film on the efficiency of the oil lubrication is also discussed.

  15. Dynamic optical properties of amorphous diamond-like carbon nanocomposite films doped with Cu and Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Tamulevičius, Tomas; Peckus, Domantas; Tamulevičiene, Asta; Vasiliauskas, Andrius; Čiegis, Arvydas; Meškinis, Šarūnas; Tamulevičius, Sigitas

    2014-09-01

    The investigation of relaxation processes in noble metal nanoparticles upon ultrafast excitations by femtosecond laser pulses is useful to understand the origin and the enhancement mechanism of the nonlinear optical properties for metaldielectric nanocomposites. In the current work we analyze diamond like carbon (DLC) film based copper and silver nanocomposites with different metal content synthesized employing unbalanced magnetron sputtering of metal targets with argon ions in acetylene gas atmosphere. Surface morphology and nanoparticle sizes were analyzed employing scanning electron and atomic force microscopy. Optical properties of the nanocomposite films were analyzed employing UV-VIS-NIR spectrometry. Transient absorption measurements were obtained employing Yb:KGW femtosecond laser spectroscopic system (HARPIA, Light Conversion Ltd.). Energy relaxation dynamics in Cu nanoparticles showed some significant differences from Ag nanoparticles. The increase of excitation intensity hasn't show additional nonlinear effects for the excited state relaxation dynamics for both kinds of samples.

  16. Protection of Diamond-like Carbon Films from Energetic Atomic Oxygen Degradation Through Si-doping Technology

    SciTech Connect

    Yokota, Kumiko; Tagawa, Masahito; Kitamura, Akira; Matsumoto, Koji; Yoshigoe, Akitaka; Teraoka, Yuden; Fontaine, Julien; Belin, Michel

    2009-01-05

    The effect of hyperthermal atomic oxygen (AO) exposure on the surface properties of Si-doped diamond-like carbon (DLC) was investigated. Two types of DLC were tested that contain approximately 10 at% and 20 at% of Si atoms. Surface analytical results of high-resolution x-ray photoelectron spectroscopy using synchrotron radiation (synchrotron radiation photoemission spectroscopy; SR-PES) as well as Rutherford backscattering spectroscopy (RBS) have been used for characterization of the AO-exposed Si-doped DLC. It was identified by SR-PES that a SiO{sub 2} layer was formed by the hyperthermal AO exposure at the Si-doped DLC surface. RBS data indicates that AO exposure leads to severe thickness loss on the undopedd DLC. In contrast, a SiO{sub 2} layer formed by the hyperthermal atomic oxygen reaction of Si-doped DLC protects the DLC underneath the SiO{sub 2} layer.

  17. Nickel nano-particle modified nitrogen-doped amorphous hydrogenated diamond-like carbon film for glucose sensing

    SciTech Connect

    Zeng, Aiping; Jin, Chunyan; Cho, Sang-Jin; Seo, Hyun Ook; Kim, Young Dok; Lim, Dong Chan; Kim, Doo Hwan; Hong, Byungyou; Boo, Jin-Hyo

    2012-10-15

    Electrochemical method has been employed in this work to modify nitrogen-doped hydrogen amorphous diamond-like carbon (N-DLC) film to fabricate nickel nano-particle-modified N-DLC electrodes. The electrochemical behavior of the nickel nano-particle-modified N-DLC electrodes has been characterized at the presence of glucose in electrolyte. Meanwhile, the N-DLC film structure and the morphology of metal nano-particles on the N-DLC surface have been investigated using micro-Raman spectroscopy and atomic force microscopy. The nickel nano-particle-modified N-DLC electrode exhibits a high catalytic activity and low background current. This result shows that the nickel nano-particle deposition on N-DLC surface could be a promising method to fabricate novel electrode materials for glucose sensing.

  18. Synthesis of Diamond-Like Carbon Films on Planar and Non-Planar Geometries by the Atmospheric Pressure Plasma Chemical Vapor Deposition Method

    NASA Astrophysics Data System (ADS)

    Noborisaka, Mayui; Hirako, Tomoaki; Shirakura, Akira; Watanabe, Toshiyuki; Morikawa, Masashi; Seki, Masaki; Suzuki, Tetsuya

    2012-09-01

    Diamond-like carbon (DLC) films were synthesized by the dielectric barrier discharge-based plasma deposition at atmospheric pressure and their hardness and gas barrier properties were measured. A decrease in size of grains and heating substrate temperature improved nano-hardness up to 3.3 GPa. The gas barrier properties of DLC-coated poly(ethylene terephthalate) (PET) sheets were obtained by 3-5 times of non-coated PET with approximately 0.5 µm in film thickness. The high-gas-barrier DLC films deposited on PET sheets are expected to wrap elevated bridge of the super express and prevent them from neutralization of concrete. We also deposited DLC films inside PET bottles by the microwave surface-wave plasma chemical vapor deposition (CVD) method at near-atmospheric pressure. Under atmospheric pressure, the films were coated uniformly inside the PET bottles, but did not show high gas barrier properties. In this paper, we summarize recent progress of DLC films synthesized at atmospheric pressure with the aimed of food packaging and concrete pillar.

  19. Magnetron sputtered diamond-like carbon microelectrodes for on-chip measurement of quantal catecholamine release from cells.

    PubMed

    Gao, Yuanfang; Chen, Xiaohui; Gupta, Sanju; Gillis, Kevin D; Gangopadhyay, Shubhra

    2008-10-01

    Carbon electrodes are widely used in electrochemistry due to their low cost, wide potential window, and low and stable background noise. Carbon-fiber electrodes (CFE) are commonly used to electrochemically measure "quantal" catecholamine release via exocytosis from individual cells, but it is difficult to integrate CFEs into lab-on-a-chip devices. Here we report the development of nitrogen doped diamond-like carbon (DLC:N) microelectrodes on a chip to monitor quantal release of catecholamines from cells. Advantages of DLC:N microelectrodes are that they are batch producible at low cost, and are harder and more durable than graphite films. The DLC:N microelectrodes were prepared by a magnetron sputtering process with nitrogen doping. The 30 microm by 40 microm DLC:N microelectrodes were patterned onto microscope glass slides by photolithography and lift-off technology. The properties of the DLC:N microelectrodes were characterized by AFM, Raman spectroscopy and cyclic voltammetry. Quantal catecholamine release was recorded amperometrically from bovine adrenal chromaffin cells on the DLC:N microelectrodes. Amperometric spikes due to quantal release of catecholamines were similar in amplitude and area as those recorded using CFEs and the background current and noise levels of microchip DLC:N electrodes were also comparable to CFEs. Therefore, DLC:N microelectrodes are suitable for microchip-based high-throughput measurement of quantal exocytosis with applications in basic research, drug discovery and cell-based biosensors.

  20. Study of Fluorine Addition Influence in the Dielectric Constant of Diamond-Like Carbon Thin Film Deposited by Reactive Sputtering

    NASA Astrophysics Data System (ADS)

    Trippe, S. C.; Mansano, R. D.

    The hydrogenated amorphous carbon films (a-C:H) or DLC (Diamond-Like Carbon) films are well known for exhibiting high electrical resistivity, low dielectric constant, high mechanical hardness, low friction coefficient, low superficial roughness and also for being inert. In this paper, we produced fluorinated DLC films (a-C:F), and studied the effect of adding CF4 on the above-mentioned properties of DLC films. These films were produced by a reactive RF magnetron sputtering system using a target of pure carbon in stable graphite allotrope. We performed measurements of electrical characteristic curves of capacitance as a function of applied tension (C-V) and current as a function of the applied tension (I-V). We showed the dielectric constant (k) and the resistivity (ρ) as functions of the CF4 concentration. On films with 65% CF4, we found that k = 2.7, and on films with 70% CF4, ρ = 12.3 × 1011 Ω cm. The value of the electrical breakdown field to films with 70% CF4 is 5.3 × 106 V/cm.

  1. Structural, mechanical and hydrophobic properties of fluorine-doped diamond-like carbon films synthesized by plasma immersion ion implantation and deposition (PIII?D)

    NASA Astrophysics Data System (ADS)

    Yao, Zh. Q.; Yang, P.; Huang, N.; Sun, H.; Wang, J.

    2004-05-01

    Fluorine-doped diamond-like carbon (a-C:F) films with different fluorine content were fabricated on Si wafer by plasma immersion ion implantation and deposition (PIII-D). Film composition and structure were characterized by X-ray photoelectron spectroscopy (XPS) and Raman scattering spectroscopy. Surface morphology and roughness were analyzed by atomic force microscopy (AFM). Hardness and scratch resistance were measured by nano-indentation and nano-scratch, respectively. Water contact angles were measured by sessile drop method. With the increase of the CF 4 flux, fluorine content was gradually increased to the film. Raman spectra indicates that these films have a diamond-like structure. The addition of fluorine to diamond-like carbon films had a critical influence on the film properties. The film surface becomes more smoother due to the etching behavior of F +. Hardness was significantly reduced, while the scratch resistance results show that these films have a fairly good adhesion to the substrate. Evident improvements of the hydrophobicity have been made to these films, with contact angles of double-stilled water approaching that of polytetrafluoroethylene (PTFE). Our study suggests that broad application regions of the fluorine-doped amorphous carbon films with diamond-like structure, synthesized by PIII-D, can be extended by combining the non-wetting properties and mechanical properties which are far superior to those of PTFE.

  2. Study of Diamond like Carbon as template for nanoimprint lithography and as a filler material for vertically aligned carbon nanotube forests

    NASA Astrophysics Data System (ADS)

    Ramachandran, Seetharaman

    Due to its tunable properties like hardness, optical gap, chemical inertness, electrical resistivity, biocompatibility etc., coatings of the material Diamond like Carbon (DLC) have been used as protective layers for various applications. In this research effort, we add to the growing list of its potential applications by proposing them as a template material for the emerging field of nanoimprint lithography. Using capacitive and inductive plasmas, we demonstrate the possibility of depositing DLC films of reasonable hardness (10-25 GPa) and wear resistance (2X that of Si and 3X that of Quartz). We have successfully used these films as a mold material to obtain feature sizes as small as 40 nm. In addition, to further the understanding of the effect of the gas phase chemistry on the film properties, the Methane discharge used for obtaining these films has been studied using techniques like Fourier Transform Infrared Spectroscopy and Optical Emission Spectroscopy. The higher degree of dissociation (up to 70%) of the precursor in case of inductive plasmas leads to selected conditions under which hard DLC films are obtained. We also show that for the same deposition conditions, films deposited on the insulating Quartz substrates are softer and more polymeric than those deposited on Si substrates. Carbon nanotubes with their unique physical properties are seen as ideal candidates for applications like field effect transistors, supercapacitors, AFM tips and electronic devices. One of the chief challenges in using them for these applications is obtaining them in a form that is easier to handle, thus enabling them to withstand the various post-processing steps. The second part of this dissertation focuses on the possibility of obtaining a Carbon-Carbon composite structure by subjecting vertically aligned Carbon nanotube forests to a PECVD based process. The distance from the top of the CNT forest that is coated with the deposited film (termed as the depth of infusion) shows

  3. Morphological and Chemical Evolution of Gradually Deposited Diamond-Like Carbon Films on Polyethylene Terephthalate: From Subplantation Processes to Structural Reorganization by Intrinsic Stress Release Phenomena.

    PubMed

    Catena, Alberto; Guo, Qiaochu; Kunze, Michael R; Agnello, Simonpietro; Gelardi, Franco M; Wehner, Stefan; Fischer, Christian B

    2016-04-27

    Diamond-like carbon (DLC) films on polyethylene terephthalate (PET) are nowadays intensively studied composites due to their excellent gas barrier properties and biocompatibility. Despite their applicative features being highly explored, the interface properties and structural film evolution of DLC coatings on PET during deposition processes are still sparsely investigated. In this study two different types of DLC films were gradually deposited on PET by radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) using acetylene plasma. The surface morphology of the deposited samples has been analyzed by atomic force microscopy (AFM). Their chemical composition was investigated by diffusive reflectance infrared Fourier transform (DRIFT) and Raman spectroscopy analysis and the surface wettability by contact angle measurements. Subplantation processes and interface effects are revealed through the morphological and chemical analysis of both types. During plasma deposition processes the increasing carbon load causes the rise of intrinsic film stress. It is proven that stress release phenomena cause the transition between polymer-like to a more cross-linked DLC network by folding dehydrogenated chains into closed 6-fold rings. These findings significantly lead to an enhanced understanding in DLC film growth mechanism by RF-PECVD processes.

  4. Metalorganic Chemical Vapor Deposition of Ruthenium-Doped Diamond like Carbon Films

    NASA Technical Reports Server (NTRS)

    Sunkara, M. K.; Ueno, M.; Lian, G.; Dickey, E. C.

    2001-01-01

    We investigated metalorganic precursor deposition using a Microwave Electron Cyclotron Resonance (ECR) plasma for depositing metal-doped diamondlike carbon films. Specifically, the deposition of ruthenium doped diamondlike carbon films was investigated using the decomposition of a novel ruthenium precursor, Bis(ethylcyclopentadienyl)-ruthenium (Ru(C5H4C2H5)2). The ruthenium precursor was introduced close to the substrate stage. The substrate was independently biased using an applied RF power. Films were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Four Point Probe. The conductivity of the films deposited using ruthenium precursor showed strong dependency on the deposition parameters such as pressure. Ruthenium doped sample showed the presence of diamond crystallites with an average size of approx. 3 nm while un-doped diamondlike carbon sample showed the presence of diamond crystallites with an average size of 11 nm. TEM results showed that ruthenium was atomically dispersed within the amorphous carbon network in the films.

  5. Silver nanoparticle-enriched diamond-like carbon implant modification as a mammalian cell compatible surface with antimicrobial properties

    PubMed Central

    Gorzelanny, Christian; Kmeth, Ralf; Obermeier, Andreas; Bauer, Alexander T.; Halter, Natalia; Kümpel, Katharina; Schneider, Matthias F.; Wixforth, Achim; Gollwitzer, Hans; Burgkart, Rainer; Stritzker, Bernd; Schneider, Stefan W.

    2016-01-01

    The implant-bone interface is the scene of competition between microorganisms and distinct types of tissue cells. In the past, various strategies have been followed to support bony integration and to prevent bacterial implant-associated infections. In the present study we investigated the biological properties of diamond-like carbon (DLC) surfaces containing silver nanoparticles. DLC is a promising material for the modification of medical implants providing high mechanical and chemical stability and a high degree of biocompatibility. DLC surface modifications with varying silver concentrations were generated on medical-grade titanium discs, using plasma immersion ion implantation-induced densification of silver nanoparticle-containing polyvinylpyrrolidone polymer solutions. Immersion of implants in aqueous liquids resulted in a rapid silver release reducing the growth of surface-bound and planktonic Staphylococcus aureus and Staphylococcus epidermidis. Due to the fast and transient release of silver ions from the modified implants, the surfaces became biocompatible, ensuring growth of mammalian cells. Human endothelial cells retained their cellular differentiation as indicated by the intracellular formation of Weibel-Palade bodies and a high responsiveness towards histamine. Our findings indicate that the integration of silver nanoparticles into DLC prevents bacterial colonization due to a fast initial release of silver ions, facilitating the growth of silver susceptible mammalian cells subsequently. PMID:26955791

  6. Silver nanoparticle-enriched diamond-like carbon implant modification as a mammalian cell compatible surface with antimicrobial properties

    NASA Astrophysics Data System (ADS)

    Gorzelanny, Christian; Kmeth, Ralf; Obermeier, Andreas; Bauer, Alexander T.; Halter, Natalia; Kümpel, Katharina; Schneider, Matthias F.; Wixforth, Achim; Gollwitzer, Hans; Burgkart, Rainer; Stritzker, Bernd; Schneider, Stefan W.

    2016-03-01

    The implant-bone interface is the scene of competition between microorganisms and distinct types of tissue cells. In the past, various strategies have been followed to support bony integration and to prevent bacterial implant-associated infections. In the present study we investigated the biological properties of diamond-like carbon (DLC) surfaces containing silver nanoparticles. DLC is a promising material for the modification of medical implants providing high mechanical and chemical stability and a high degree of biocompatibility. DLC surface modifications with varying silver concentrations were generated on medical-grade titanium discs, using plasma immersion ion implantation-induced densification of silver nanoparticle-containing polyvinylpyrrolidone polymer solutions. Immersion of implants in aqueous liquids resulted in a rapid silver release reducing the growth of surface-bound and planktonic Staphylococcus aureus and Staphylococcus epidermidis. Due to the fast and transient release of silver ions from the modified implants, the surfaces became biocompatible, ensuring growth of mammalian cells. Human endothelial cells retained their cellular differentiation as indicated by the intracellular formation of Weibel-Palade bodies and a high responsiveness towards histamine. Our findings indicate that the integration of silver nanoparticles into DLC prevents bacterial colonization due to a fast initial release of silver ions, facilitating the growth of silver susceptible mammalian cells subsequently.

  7. Study on Exploding Wire Compression for Evaluating Electrical Conductivity in Warm-Dense Diamond-Like-Carbon

    NASA Astrophysics Data System (ADS)

    Sasaki, Toru; Takahashi, Kazumasa; Kudo, Takahiro; Kikuchi, Takashi; Aso, Tsukasa; Harada, Nob.; Fujioka, Shinsuke; Horioka, Kazuhiko

    2016-03-01

    To improve a coupling efficiency for the fast ignition scheme of the inertial confinement fusion, fast electron behaviors as a function of an electrical conductivity are required. To evaluate the electrical conductivity for low-Z materials as a diamond-like-carbon (DLC), we have proposed a concept to investigate the properties of warm dense matter (WDM) by using pulsed-power discharges. The concept of the evaluation of DLC for WDM is a shock compression driven by an exploding wire discharge with confined by a rigid capillary. The qualitatively evaluation of the electrical conductivity for the WDM DLC requires a small electrical conductivity of the exploding wire. To analyze the electrical conductivity of exploding wire, we have demonstrated an exploding wire discharge in water for gold. The results indicated that the electrical conductivity of WDM gold for 5000 K of temperature has an insulator regime. It means that the shock compression driven by the exploding wire discharge with confined by the rigid capillary is applied for the evaluation of electrical conductivity for WDM DLC.

  8. The protective properties of ultra-thin diamond like carbon films for high density magnetic storage devices

    NASA Astrophysics Data System (ADS)

    Zhong, Min; Zhang, Chenhui; Luo, Jianbin; Lu, Xinchun

    2009-10-01

    With the increase of magnetic storage density, the thickness of the protective diamond like carbon (DLC) film on the surfaces of head and disk is required as thin as possible. In this paper, the structure, mechanical properties and corrosion and oxidation resistance of ultra-thin DLC films are investigated. The ultra-thin DLC films were deposited by using filtered cathodic vacuum arc (FCVA) technique. The exact thickness of the ultra-thin DLC film was determined by high resolution transmission electron microscope (HRTEM). Raman analysis indicates that the ultra-thin DLC film presents ta-C structure with high sp 3 fraction. In the wear test, a diamond tip was used to simulate a single-asperity contact with the film surface and the wear marks were produced on the film surface. The wear depths decrease with film thickness increasing. If the film thickness was 1.4 nm or above, the wear depth was much lower than that of Si substrate. This indicates that the ultra-thin DLC film with thickness of 1.4 nm shows excellent wear resistance. Corrosion tests in water and oxidation tests in air were carried out to investigate the diffusion barrier effect of the ultra-thin DLC films. The results show that the DLC film with thickness of 1.4 nm provides adequate coverage on the substrate and has good corrosion and oxidation resistance.

  9. Comparative surface and nano-tribological characteristics of nanocomposite diamond-like carbon thin films doped by silver

    SciTech Connect

    Zhang, Han-Shen; Endrino, Jose L.; Anders, Andre

    2008-07-10

    In this study we have deposited silver-containing hydrogenated and hydrogen-free diamond-like carbon (DLC) nanocomposite thin films by plasma immersion ion implantation-deposition methods. The surface and nano-tribological characteristics were studied by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and nano-scratching experiments. The silver doping was found to have no measurable effect on sp2-sp3 hybridization of the hydrogenated DLC matrix and only a slight effect on the hydrogen-free DLC matrix. The surface topography was analyzed by surface imaging. High- and low-order roughness determined by AFM characterization was correlated to the DLC growth mechanism and revealed the smoothing effect of silver. The nano-tribological characteristics were explained in terms of friction mechanisms and mechanical properties in correlation to the surface characteristics. It was discovered that the adhesion friction was the dominant friction mechanism; the adhesion force between the scratching tip and DLC surface was decreased by hydrogenation and increased by silver doping.

  10. Influence of Hydrogen Content on Optical and Mechanical Performances of Diamond-Like Carbon Films on Glass Substrate

    NASA Astrophysics Data System (ADS)

    Sun, Yao; Huang, Xing-Ye; Wang, Hong

    2016-04-01

    The protective layer for cover glass of touch panel screen for electronic mobile devices is required to have good mechanical properties and decent optical transparency simultaneously. The hydrogenated diamond-like carbon (a-C:H) films were deposited on glass substrate by RF-PECVD in the negative stage potential mode (NP mode), as well as the ground stage potential mode (GP mode). The impact of hydrogen content, affected by stage potential and RF power, on optical and mechanical properties was investigated. The results show that hydrogen content decreases with increasing RF power, due to the dehydrogenation effect. Higher hydrogen content in films results in lower refractive index, lower extinction coefficient, lower optical absorptions, larger optical band gap and higher transmittance, but lower hardness and wearing resistance. Therefore, although the GP mode DLC is optically favorable because of higher hydrogen content, the NP mode one is far more superior from mechanical standpoint. A compromise can be reached to deposit an ultrathin layer of DLC in NP mode, which offers a good combination of properties to meet the requirement for the protective layer of cover glass.

  11. Cell adhesion and growth on ultrananocrystalline diamond and diamond-like carbon films after different surface modifications

    NASA Astrophysics Data System (ADS)

    Miksovsky, J.; Voss, A.; Kozarova, R.; Kocourek, T.; Pisarik, P.; Ceccone, G.; Kulisch, W.; Jelinek, M.; Apostolova, M. D.; Reithmaier, J. P.; Popov, C.

    2014-04-01

    Diamond and diamond-like carbon (DLC) films possess a set of excellent physical and chemical properties which together with a high biocompatibility make them attractive candidates for a number of medical and biotechnological applications. In the current work thin ultrananocrystalline diamond (UNCD) and DLC films were comparatively investigated with respect to cell attachment and proliferation after different surface modifications. The UNCD films were prepared by microwave plasma enhanced chemical vapor deposition, the DLC films by pulsed laser deposition (PLD). The films were comprehensively characterized with respect to their basic properties, e.g. crystallinity, morphology, chemical bonding nature, etc. Afterwards the UNCD and DLC films were modified applying O2 or NH3/N2 plasmas and UV/O3 treatments to alter their surface termination. The surface composition of as-grown and modified samples was studied by X-ray photoelectron spectroscopy (XPS). Furthermore the films were characterized by contact angle measurements with water, formamide, 1-decanol and diiodomethane; from the results obtained the surface energy with its dispersive and polar components was calculated. The adhesion and proliferation of MG63 osteosarcoma cells on the different UNCD and DLC samples were assessed by measurement of the cell attachment efficiency and MTT assays. The determined cell densities were compared and correlated with the surface properties of as-deposited and modified UNCD and DLC films.

  12. Mechanical and tribological characterization of tetrahedral diamond-like carbon deposited by femtosecond pulsed laser deposition on pre-treated orthopaedic biomaterials

    NASA Astrophysics Data System (ADS)

    Loir, A.-S.; Garrelie, F.; Donnet, C.; Subtil, J.-L.; Belin, M.; Forest, B.; Rogemond, F.; Laporte, P.

    2005-07-01

    Femtosecond pulsed laser deposition (PLD) has been performed using a mode-locked Ti:sapphire laser including an amplification stage (150 fs, 800 nm, 1 kHz) to deposit tetrahedral-amorphous carbon films (ta-C) on AISI 316L stainless steel and ultra high molecular weight polyethylene, in perspective to extend the wear resistance of materials used in hip joints. Ta-C films have been elaborated in high vacuum conditions at room temperature. The diamond-like coated silicon substrates exhibit high wear resistance (in the 10 -8-10 -9 mm 3 (N m) -1 range) with moderate hardness (in the 20-30 GPa range), which may be favorable for the accommodation motion between contacting surfaces in a hip joint. In situ sputter cleaning of the orthopaedic substrates in argon plasma prior to carbon deposition has been investigated, leading to the enhancement of the adhesion of the films onto the stainless steel substrates. The adhesion properties of films deposited in various conditions on metallic substrates have been studied by tensile tests. The tribological behavior of the coatings deposited on cleaned substrates have been widely investigated in a pin-on-flat configuration in ambient air and Ringer solution. Finally, a DLC thin film with an homogeneous thickness has been deposited on hemispherical surface of 22.2 mm in diameter of a stainless steel femoral head of a hip prosthesis, whose wear behavior will be quantified using a hip joint simulator during one million of cycles (corresponding to the human activity during one year).

  13. Development of program package for investigation and modeling of carbon nanostructures in diamond like carbon films with the help of Raman scattering and infrared absorption spectra line resolving

    NASA Astrophysics Data System (ADS)

    Hayrapetyan, David B.; Hovhannisyan, Levon; Mantashyan, Paytsar A.

    2013-04-01

    The analysis of complex spectra is an actual problem for modern science. The work is devoted to the creation of a software package, which analyzes spectrum in the different formats, possesses by dynamic knowledge database and self-study mechanism, performs automated analysis of the spectra compound based on knowledge database by application of certain algorithms. In the software package as searching systems, hyper-spherical random search algorithms, gradient algorithms and genetic searching algorithms were used. The analysis of Raman and IR spectrum of diamond-like carbon (DLC) samples were performed by elaborated program. After processing the data, the program immediately displays all the calculated parameters of DLC.

  14. Mechanical properties and platelet adhesion behavior of diamond-like carbon films synthesized by pulsed vacuum arc plasma deposition

    NASA Astrophysics Data System (ADS)

    Leng, Y. X.; Chen, J. Y.; Yang, P.; Sun, H.; Wan, G. J.; Huang, N.

    2003-05-01

    Diamond-like carbon (DLC) is an attractive biomedical material due to its high inertness and excellent mechanical properties. In this study, DLC films were fabricated on Ti6Al4V and Si(1 0 0) substrates at room temperature by pulsed vacuum arc plasma deposition. By changing the argon flow from 0 to 13 sccm during deposition, the effects of argon flow on the characteristics of the DLC films were systematically examined to correlate to the blood compatibility. The microstructure and mechanical properties of the films were investigated using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) surface analysis, a nano-indenter and pin-on-disk tribometer. The blood compatibility of the films was evaluated using in vitro platelet adhesion investigation, and the quantity and morphology of the adherent platelets was investigated employing optical microscopy and scanning electron microscopy. The Raman spectroscopy results showed a decreasing sp 3 fraction (an increasing trend in ID/ IG ratio) with increasing argon flow from 0 to 13 sccm. The sp 3:sp 2 ratio of the films was evaluated from the deconvoluted XPS spectra. We found that the sp 3 fraction decreased as the argon flow was increased from 0 to 13 sccm, which is consistent with the results of the Raman spectra. The mechanical properties results confirmed the decreasing sp 3 content with increasing argon flow. The Raman D-band to G-band intensity ratio increased and the platelet adhesion behavior became better with higher flow. This implies that the blood compatibility of the DLC films is influenced by the sp 3:sp 2 ratio. DLC films deposited on titanium alloys have high wear resistance, low friction and good adhesion.

  15. Molecular Dynamic Simulation of Collision-Induced Third-Body Formation in Hydrogen-Free Diamond-Like Carbon Asperities.

    PubMed

    von Lautz, Julian; Pastewka, Lars; Gumbsch, Peter; Moseler, Michael

    The collision of two cylindrical hydrogen-free diamond-like carbon (DLC) asperities with approximately 60 % sp(3) hybridization has been studied using classical molecular dynamics. The severity of the collision can be controlled by the impact parameter b that measures the width of the projected overlap of the two cylinders. For a cylinder radius of R = 23 nm, three collisions with b = 0.5 nm, b = 1 nm and b = 2.0 nm are compared. While for the two small b a single shear band between the collision partners and a strongly localized sp(2)/sp(1) hybridised third-body zone between the asperities is observed, the b = 2 nm collision is accompanied by pronounced plastic deformation in both asperities that destabilize the metastable sp(3)-rich phase leading to a drastic increase in the amount of rehybridized tribomaterial. In addition, pronounced roughening of the cylinder surfaces, asymmetric material transfer and the generation of wear debris are found in this case. For the b = 0.5 and 1 nm collision, the evolution of third-body volume can be quantitatively described by a simple geometric overlap model that assumes a sliding-induced phase transformation localized between both asperities. For b = 2 nm, this model underestimates the third-body volume by more than 150 % indicating that plasticity has to be taken into account in simple geometric models of severe DLC/DLC asperity collisions.

  16. Improvement in the degradation resistance of silicon nanostructures by the deposition of diamond-like carbon films

    SciTech Connect

    Klyui, N. I. Semenenko, M. A.; Khatsevich, I. M.; Makarov, A. V.; Kabaldin, A. N.; Fomovskii, F. V.; Han, Wei

    2015-08-15

    It is established that the deposition of a diamond-like film onto a structure with silicon nanoclusters in a silicon dioxide matrix yields an increase in the long-wavelength photoluminescence intensity of silicon nanoclusters due to the passivation of active-recombination centers with hydrogen and a shift of the photoluminescence peak to the region of higher photosensitivity of silicon-based solar cells. It is also shown that, due to the deposited diamond-like film, the resistance of such a structure to degradation upon exposure to γ radiation is improved, which is also defined by the effect of the passivation of radiation-induced activerecombination centers by hydrogen that is released from the films during treatment.

  17. Characteristics and mechanical properties of titanium-containing diamond like carbon films deposited by cathodic arc evaporation.

    PubMed

    Tsai, Pi-Chuen; Chiang, Jueh-Yu; Hwang, Yen-Fei

    2008-05-01

    Depositions of titanium-containing diamond-like carbon (Ti-DLC) films were conducted by mixing C+ and Ti+ plasma streams originated from cathodic arc plasma sources in argon (Ar). The deposition was processed at Ti target current ranging from 20 Amp to 70 Amp. Film characteristics were investigated using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS). Film microstructures were evaluated using field emission scanning electron microscopy (FEGSEM), an atomic force microscope (AFM), X-ray diffractometry (XRD) and high-resolution transmission electron microscopy (HRTEM). Mechanical properties were investigated by using a nanoindentation tester and ball on disc wear test. Results shows that surface roughness (Ra) of the films ranged between 2.4 and 7.2 nm and roughness increased relative to the increase in Ti target current. The FESEM studies showed that the surface micrographs of Ti-DLC films revealed a cauliflower-like microstructure and the cross-sectional micrograph revealed a snake-skin like structure. HRTEM studies showed that the Ti-DLC films consisted of nano scale TiC particles which were comparable with low angle XRD and XPS results. XPS analysis established that the Ti2p spectrum is present when the Ti target current reaches 30 Amp or higher. Ti concentration increased as the Ti target current was increased. An extremely thin TiO2 layer exists on the top of the Ti-DLC films which was comparable with the AES results. The film thickness which could be deposited for Ti-DLC is much higher than that of conventional DLC films. Nanoindentation tests show that the nanohardness of the films ranging 15-22 GPa, with Er values ranging from 145 to 175 GPa. The wear test demonstrates the friction coefficient of the 420SS substrate, DLC and Ti-DLC films were about 0.8, 0.3 and 0.2, respectively. Obviously, the friction coefficients of the Ti-DLC films were lower than that of the DLC films.

  18. Low-dielectric-constant fluorinated diamond-like carbon thin films by plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Yi, Jeong Woo

    Fluorinated amorphous carbon (a-C:F) thin films are developed for a low dielectric constant interlayer dielectric material from hexafluorobenze (C 6F6) or 1,1,1,2-tetrafluoroethane (FCH2CF 4) as the source gas and argon as the diluent gas in an asymmetric capacitively coupled rf (radio frequency) plasma reactor and an inductively coupled plasma reactor. Effects of input rf power, fluorination, applied bias voltage and post annealing on the properties of a-C:F films are investigated. For depositing a-C:F films from highly diluted C6F6 (3%) and argon (97%) in the capacitively rf plasma reactor at 150 mTorr, the dielectric constant of the film increases from 2.0 to 2.8 as the rf power is increased from 10 W to 70 W, while the optical energy gap decreases from 2.6 eV to 1.9 eV and the transparency in a ultra-violet range is degraded. At input power of 100 W, the deposited film exhibits high residual stress of 40 MPa and easily peeled off by a Scotch tape test. This is due to high self-bias voltage (-230 V) developed at the substrate holder during deposition. When depositing amorphous carbon films from tetrafluoroethane (TFE) and methane in the capacitively coupled plasma reactor, the incorporation of fluorine in the film is increased with increasing TFE fraction in the feed gas mixture. The dielectric constant of the a-C:F film deposited from pure TFE is as low as 2.3, but the film exhibits poor thermal stability while a-C:H (diamond-like carbon) film deposited from pure methane has a dielectric constant of 3.8 and shows good thermal stability up to 400°C. As the TFE content in the feed is increased, the dielectric constant and the refractive index decrease while the transparency of the film is enhanced significantly. When depositing a-C:F films from C6F6 (4 sccm) and Ar (5 sccm) in the inductively coupled rf plasma reactor, the bias voltage (from a separate 100 KHz source) applied to the substrate holder affects the film properties significantly. As the negative bias

  19. Bias in bonding behavior among boron, carbon, and nitrogen atoms in ion implanted a-BN, a-BC, and diamond like carbon films

    SciTech Connect

    Genisel, Mustafa Fatih; Uddin, Md. Nizam; Say, Zafer; Bengu, Erman; Kulakci, Mustafa; Turan, Rasit; Gulseren, Oguz

    2011-10-01

    In this study, we implanted N{sup +} and N{sub 2}{sup +} ions into sputter deposited amorphous boron carbide (a-BC) and diamond like carbon (DLC) thin films in an effort to understand the chemical bonding involved and investigate possible phase separation routes in boron carbon nitride (BCN) films. In addition, we investigated the effect of implanted C{sup +} ions in sputter deposited amorphous boron nitride (a-BN) films. Implanted ion energies for all ion species were set at 40 KeV. Implanted films were then analyzed using x-ray photoelectron spectroscopy (XPS). The changes in the chemical composition and bonding chemistry due to ion-implantation were examined at different depths of the films using sequential ion-beam etching and high resolution XPS analysis cycles. A comparative analysis has been made with the results from sputter deposited BCN films suggesting that implanted nitrogen and carbon atoms behaved very similar to nitrogen and carbon atoms in sputter deposited BCN films. We found that implanted nitrogen atoms would prefer bonding to carbon atoms in the films only if there is no boron atom in the vicinity or after all available boron atoms have been saturated with nitrogen. Implanted carbon atoms also preferred to either bond with available boron atoms or, more likely bonded with other implanted carbon atoms. These results were also supported by ab-initio density functional theory calculations which indicated that carbon-carbon bonds were energetically preferable to carbon-boron and carbon-nitrogen bonds.

  20. Electron Cyclotron Resonance-Sputtered Nanocarbon Film Electrode Compared with Diamond-Like Carbon and Glassy Carbon Electrodes as Regards Electrochemical Properties and Biomolecule Adsorption

    NASA Astrophysics Data System (ADS)

    Xue, Qiang; Kato, Dai; Kamata, Tomoyuki; Umemura, Shigeru; Hirono, Shigeru; Niwa, Osamu

    2012-09-01

    The electrochemical properties and biocompatible characteristics at an electron cyclotron resonance (ECR)-sputtered nanocarbon film electrode, a diamond-like carbon (DLC) electrode and a glassy carbon (GC) electrode have been studied. The three carbon electrodes show significant current reductions with increased peak separations as a result of protein fouling before oxygen plasma treatment, but the current reductions of the ECR-sputtered nanocarbon and DLC film electrodes are smaller than that of the GC electrode due to their superior surface flatness. The oxygen plasma pretreated ECR-sputtered nanocarbon film electrode exhibits a significant improvement in anti-fouling performance with an improved electron transfer. This is because the pretreated ECR-sputtered nanocarbon film enabled the surface to introduce surface oxygen functionalities that not only improve the interaction between the analytes and the electrode surface but also make the film surface more hydrophilic, which is important for the suppression of biomolecule adsorption. At the same time, the pretreated ECR-sputtered nanocarbon film also retained an ultraflat surface even after pretreatment as a result of the low background current. This excellent performance can only be achieved with our ECR-sputtered nanocarbon film, indicating that our film is promising for application to electrochemical detectors for various biomolecular analytes.

  1. Investigation of diamond-like carbon samples as a charge state conversion surface for neutral atom imaging detectors in space applications

    NASA Astrophysics Data System (ADS)

    Brigitte Neuland, Maike; Riedo, Andreas; Scheer, Jürgen; Wurz, Peter

    2014-05-01

    The detection of energetic neutral atoms is a substantial requirement on every space mission mapping particle populations of a planetary magnetosphere or plasma of the interstellar medium. For imaging neutrals, these first have to be ionized. Regarding the constraints of weight, volume and power consumption, the technique of surface ionization complies with all specifications of a space mission. Particularly low energy neutral atoms, which cannot be ionized by passing through a foil, are ionized by scattering on a charge state conversion surface. Since more than 30 years intense research work is done to find suitable materials for use as charge state conversion surfaces. Crucial parameters are the ionisation efficiency of the surface material and the scattering properties. Against all expectations, insulators showed very promising characteristics for serving as conversion surfaces. Particularly diamond-like carbon was proven advantageously: While efficiently ionising incoming neutral atoms, diamond stands out by its durability and chemical inertness. In the IBEX-Lo sensor, a diamond-like carbon surface is used for ionisation of neutral atoms. Energy resolved maps of neutral atoms from the IBEX mission revealed phenomena of the interaction between heliosphere and local interstellar medium (LISM) that demand for new theory and explanations [McComas et al., 2011]. Building on the successes of the IBEX mission, a follow up mission concept to further explore the boundaries of the heliosphere already exists. The Interstellar MApping Probe (IMAP) is planned to map neutral atoms in a larger energy range and with a distinct better angular resolution and sensitivity than IBEX [McComas et al.]. The aspired performance of the IMAP sensors implies also for charge state conversion surfaces with improved characteristics. We investigated samples of diamond-like carbon, manufactured by the chemical vapour and pulsed laser deposition method, regarding their ionisation efficiency

  2. Diamond-like-carbon nanoparticle production and agglomeration following UV multi-photon excitation of static naphthalene/helium gas mixtures.

    PubMed

    Walsh, A J; Tielens, A G G M; Ruth, A A

    2016-07-14

    We report the formation of nanoparticles with significant diamond character after UV multi-photon laser excitation of gaseous naphthalene, buffered in static helium gas, at room temperature. The nanoparticles are identified in situ by their absorption and scattering spectra between 400 and 850 nm, which are modeled using Mie theory. Comparisons of the particles' spectroscopic and optical properties with those of carbonaceous materials indicate a sp(3)/sp(2) hybridization ratio of 8:1 of the particles formed. The particle extinction in the closed static (unstirred) gas-phase system exhibits a complex and quasi-oscillatory time dependence for the duration of up to several hours with periods ranging from seconds to many minutes. The extinction dynamics of the system is based on a combination of transport features and particle interaction, predominantly agglomeration. The relatively long period of agglomeration allows for a unique analysis of the agglomeration process of diamond-like carbon nanoparticles in situ.

  3. Low reflection and high transmission by a layered structure containing diamond-like carbon, porous silicon, and left-handed material

    NASA Astrophysics Data System (ADS)

    Ubeid, Muin F.; Shabat, Mohammed M.; Altanany, Sameh M.

    2017-03-01

    In this paper, we propose and theoretically analyze a stratified waveguide structure comprised of diamond-like carbon (DLC), porous silicon (PS), and left-handed material (LHM) subjected to incident light in order to achieve low reflection and high transmission. The proposed waveguide structure is situated between two half free spaces and a TE polarized plane wave incident on it. The main parameters of each material are given and the required equations for the electromagnetic plane wave propagation are presented. Transfer matrix method is implemented to find out the characteristics of the reflected and transmitted powers. In the numerical results, the mentioned powers are computed and illustrated as a function of the incidence angle, the frequency, and the slab thickness to demonstrate the main parameters for low reflection and high transmission. These theoretical parameters could be useful to the researchers and designers working in the area of solar cells and optical sensors.

  4. SERS activity of Ag decorated nanodiamond and nano-β-SiC, diamond-like-carbon and thermally annealed diamond thin film surfaces.

    PubMed

    Kuntumalla, Mohan Kumar; Srikanth, Vadali Venkata Satya Siva; Ravulapalli, Satyavathi; Gangadharini, Upender; Ojha, Harish; Desai, Narayana Rao; Bansal, Chandrahas

    2015-09-07

    In the recent past surface enhanced Raman scattering (SERS) based bio-sensing has gained prominence owing to the simplicity and efficiency of the SERS technique. Dedicated and continuous research efforts have been made to develop SERS substrates that are not only stable, durable and reproducible but also facilitate real-time bio-sensing. In this context diamond, β-SiC and diamond-like-carbon (DLC) and other related thin films have been promoted as excellent candidates for bio-technological applications including real time bio-sensing. In this work, SERS activities of nanodiamond, nano-β-SiC, DLC, thermally annealed diamond thin film surfaces were examined. DLC and thermally annealed diamond thin films were found to show SERS activity without any metal nanostructures on their surfaces. The observed SERS activities of the considered surfaces are explained in terms of the electromagnetic enhancement mechanism and charge transfer resonance process.

  5. Thickness Effects of TiC Interlayer on Tribological Properties of Diamond-Like Carbon Prepared by Unbalanced Magnetron Sputtering Method.

    PubMed

    Park, Chulmin; Lee, Jaehyeong; Park, Yong Seob

    2015-11-01

    We investigated the tribological properties of diamond-like carbon (DLC) films prepared with TiC interlayer of various thicknesses as the adhesive layer. DLC and TiC thin films were prepared using unbalanced magnetron (UBM) sputtering method using graphite and titanium as targets. TiC films as the interlayer were deposited under DLC films and various physical, tribological, and structural properties of the films fabricated with various TiC interlayer thicknesses were investigated. With various TiC interlayer thicknesses under DLC films, the tribological properties of films were improved with increasing thickness and the DLC/TiC layer fabricated by unbalanced magnetron sputtering method are exhibited maximum high hardness over 27 GPa and high elastic modulus over 242 GPa, and a smooth surface below 0.09 nm.

  6. Microstructure and surface properties of chromium-doped diamond-like carbon thin films fabricated by high power pulsed magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Wu, Zhongzhen; Tian, Xiubo; Gui, Gang; Gong, Chunzhi; Yang, Shiqin; Chu, Paul K.

    2013-07-01

    High power pulsed magnetron sputtering (HPPMS) has attracted much interest due to the large plasma density and high ionization rate of sputtered materials. It is expected to produce a highly ionized C flux from a graphite target but unfortunately, the ionization rate of carbon is still very small and the discharge on a solid carbon target is unstable as well. In this work, a stable discharged chromium target is used in the preparation of chromium-doped diamond-like carbon (Cr-DLC) films in HPPMS in reactive C2H2 gas, but the unstable graphite. The chromium concentration in the Cr-DLC films is limited by surface poisoning due to reactive gas. Less than 2% of Cr is incorporated into the DLC films at C2H2 flow rate of 5 sccm or higher. However, as a result of the high ionization rate of the reactive gas in HPPMS, intense ion bombardment of the substrate is realized. The films show a smooth surface and a dense structure with a large sp3 concentration. As the C2H2 flow increase, the sp3 fraction increase and the sp3 to sp2 ratio increase to 0.75 at a C2H2 flow rate of 10 sccm. Compared to the substrate, the Cr-DLC films have lower friction and exhibit excellent corrosion resistance.

  7. Structural and electrical properties and current-voltage characteristics of nitrogen-doped diamond-like carbon films on Si substrates by plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Masato; Murakami, Kazuki; Magara, Kohei; Nakamura, Kazuki; Ohashi, Haruka; Tokuda, Kengo; Takami, Takahiro; Ogasawara, Haruka; Enta, Yoshiharu; Suzuki, Yushi; Ando, Satoshi; Nakazawa, Hideki

    2016-06-01

    We have deposited nitrogen-doped diamond-like carbon (N-DLC) films by plasma-enhanced chemical vapor deposition using CH4, N2, and Ar, and investigated the effects of N doping on the structure and the electrical, mechanical, and optical properties of the N-DLC films. We fabricated undoped DLC/p-type Si and N-DLC/p-type Si heterojunctions and examined the current-voltage characteristics of the heterojunctions. When the N2 flow ratio was increased from 0 to 3.64%, the resistivity markedly decreased from the order of 105 Ω·cm to that of 10-2 Ω·cm and the internal stress also decreased. The resistivity gradually increased with increasing N2 flow ratio from 3.64 to 13.6%, and then it decreased at a N2 flow ratio of 13.6%. These behaviors can be explained in terms of the clustering of sp2 carbons and the formation of sp3C-N, sp2C=N, sp1C≡N, and C-H n bonds. The rectification ratio of the heterojunction using the N-DLC film prepared at 3.64% was 35.8 at ±0.5 V.

  8. Incorporation of Si and SiO(x) into diamond-like carbon films: impact on surface properties and osteoblast adhesion.

    PubMed

    Randeniya, L K; Bendavid, A; Martin, P J; Amin, Md S; Preston, E W; Magdon Ismail, F S; Coe, S

    2009-06-01

    The interaction of human osteoblast cells with diamond-like carbon films incorporating silicon and silicon oxide (SiO(x), 1 < or = x < or = 1.5) and synthesized using the direct-current plasma-activated chemical vapour deposition method was investigated. Cell culture studies were performed for films with Si contents ranging from approximately 4 at.% to 15 at.%. Substantial differences between Si-incorporated and SiO(x)-incorporated films were found for the bonding environments of Si atoms and the hybridization of underlying carbon structures. However, osteoblast-attachment studies did not show statistically significant trends in properties of cell growth (count, area and morphology) that can be attributed either to the Si content of the films or to the chemical structure of the films. The surface energy decreased by 40% as the Si content of the SiO(x) incorporated DLC films increased to 13 at.%. The cell adhesion properties however did not change in response to lowering of the surface energy. The incorporation of both Si and SiO(x) leads to a beneficial reduction in the residual stress of the films. The average roughness of the films increases and the hardness decreases when Si and SiO(x) are added to DLC films. The impact of these changes for load-bearing biomedical applications can be determined only by carefully controlled experiments using anatomic simulators.

  9. Complete characterization by Raman spectroscopy of the structural properties of thin hydrogenated diamond-like carbon films exposed to rapid thermal annealing

    SciTech Connect

    Rose, Franck Wang, Na; Smith, Robert; Xiao, Qi-Fan; Dai, Qing; Marchon, Bruno; Inaba, Hiroshi; Matsumura, Toru; Saito, Yoko; Matsumoto, Hiroyuki; Mangolini, Filippo; Carpick, Robert W.

    2014-09-28

    We have demonstrated that multi-wavelength Raman and photoluminescence spectroscopies are sufficient to completely characterize the structural properties of ultra-thin hydrogenated diamond-like carbon (DLC:H) films subjected to rapid thermal annealing (RTA, 1 s up to 659 °C) and to resolve the structural differences between films grown by plasma-enhanced chemical vapor deposition, facing target sputtering and filtered cathodic vacuum arc with minute variations in values of mass density, hydrogen content, and sp³ fraction. In order to distinguish unequivocally between films prepared with different density, thickness, and RTA treatment, a new method for analysis of Raman spectra was invented. This newly developed analysis method consisted of plotting the position of the Raman G band of carbon versus its full width at half maximum. Moreover, we studied the passivation of non-radiative recombination centers during RTA by performing measurements of the increase in photoluminescence in conjunction with the analysis of DLC:H networks simulated by molecular dynamics. The results show that dangling bond passivation is primarily a consequence of thermally-induced sp² clustering rather than hydrogen diffusion in the film.

  10. Hemocompatibility of nitrogen-doped, hydrogen-free diamond-like carbon prepared by nitrogen plasma immersion ion implantation-deposition.

    PubMed

    Kwok, Sunny C H; Yang, Ping; Wang, Jin; Liu, Xuanyong; Chu, Paul K

    2004-07-01

    Amorphous hydrogenated carbon (a-C:H) has been shown to be a potential material in biomedical devices such as artificial heart valves, bone implants, and so on because of its chemical inertness, low coefficient of friction, high wear resistance, and good biocompatibility. However, the biomedical characteristics such as blood compatibility of doped hydrogen-free diamond-like carbon (DLC) have not been investigated in details. We recently began to investigate the potential use of nitrogen-doped, hydrogen-free DLC in artificial heart valves. In our experiments, a series of hydrogen-free DLC films doped with nitrogen were synthesized by plasma immersion ion implantation-deposition (PIII-D) utilizing a pulsed vacuum arc plasma source and different N to Ar (FN/FAr) gas mixtures in the plasma chamber. The structures and properties of the film were evaluated by Raman spectroscopy, Rutherford backscattering spectrometry (RBS), and X-ray photoelectron spectroscopy (XPS). To assess the blood compatibility of the films and the impact on the blood compatibility by the presence of nitrogen, platelet adhesion tests were conducted. Our results indicate that the blood compatibility of both hydrogen-free carbon films (a-C) and amorphous carbon nitride films are better than that of low-temperature isotropic pyrolytic carbon (LTIC). The experimental results are consistent with the relative theory of interfacial energy and surface tension including both dispersion and polar components. Our results also indicate that an optimal fraction of sp2 bonding is desirable, but an excessively high nitrogen concentration degrades the properties to an extent that the biocompatibility can be worse than that of LTIC.

  11. Patterning of diamond like carbon films for sensor applications using silicon containing thermoplastic resist (SiPol) as a hard mask

    NASA Astrophysics Data System (ADS)

    Virganavičius, D.; Cadarso, V. J.; Kirchner, R.; Stankevičius, L.; Tamulevičius, T.; Tamulevičius, S.; Schift, H.

    2016-11-01

    Patterning of diamond-like carbon (DLC) and DLC:metal nanocomposites is of interest for an increasing number of applications. We demonstrate a nanoimprint lithography process based on silicon containing thermoplastic resist combined with plasma etching for straightforward patterning of such films. A variety of different structures with few hundred nanometer feature size and moderate aspect ratios were successfully realized. The quality of produced patterns was directly investigated by the means of optical and scanning electron microscopy (SEM). Such structures were further assessed by employing them in the development of gratings for guided mode resonance (GMR) effect. Optical characterization of such leaky waveguide was compared with numerical simulations based on rigorous coupled wave analysis method with good agreement. The use of such structures as refractive index variation sensors is demonstrated with sensitivity up to 319 nm/RIU, achieving an improvement close to 450% in sensitivity compared to previously reported similar sensors. This pronounced GMR signal fully validates the employed DLC material, the technology to pattern it and the possibility to develop DLC based gratings as corrosion and wear resistant refractometry sensors that are able to operate under harsh conditions providing great value and versatility.

  12. Self-enhanced plasma discharge effect in the deposition of diamond-like carbon films on the inner surface of slender tube

    NASA Astrophysics Data System (ADS)

    Xu, Yi; Li, Liuhe; Luo, Sida; Lu, Qiuyuan; Gu, Jiabin; Lei, Ning; Huo, Chunqin

    2017-01-01

    Enhanced glow discharge plasma immersion ion implantation and deposition (EGD-PIII&D) have been proved to be highly effective for depositing diamond-like carbon (DLC) films on the inner surface of the slender quartz tube with a deposition rate of 1.3 μm/min. Such a high-efficiency DLC films deposition was explained previously as the short electrons mean free path to cause large collision frequency between electrons and neutral particles. However, in this paper, we found that the inner surface material of the tube itself play a vital role on the films deposition. To disclose the mechanism of this phenomenon, the effect of different inner surface materials on plasma discharge was experimentally and theoretically investigated. Then a self-enhancing plasma discharge is discovered. It is found that secondary electrons emitted from the inner surface material, whatever it is the tube inner surface or deposited DLC films, can dramatically enhance the plasma discharge to improve the DLC films deposition rate.

  13. On The structure Of Deposited Diamond-Like Carbon Films Produced By Rf (13.56MHz)CH{sub 4} Plasma

    SciTech Connect

    Ouchabane, M.; Henda, K.; Kechouane, M.; Salah, H.; Touchrift, B.; Tabet, N.

    2008-09-23

    Plasma enhanced chemical vapour deposition technique is used to grow diamond-like carbon films using pure methane gas plasma. It is known that the structure of the deposited films is largely influenced by the self-bias voltage values and thereafter all the film properties are a function of the structure; this concerns hydrogen concentration and sp{sup 3}/sp{sup 2} hybridisation ratio in DLC films. Then monitoring DLC film properties requires the control of hydrogen concentration and hybridisation rates. This investigation is focused on the study of the structure changes upon the deposition conditions. The correlation between the structure and the deposition conditions was investigated by using various characterization techniques. Fourier Transform Infra-Red Spectroscopy (FTIR) was used to analyse the absorption of optically active hydrogen in the DLC films. The deconvolution of 2900 cm{sup -1} absorption band allows the analysis of all different hybridisations and configurations forming the structure. The total quantity of hydrogen in the film is evaluated by Elastic Recoil Detection Analysis (ERDA). The quantification of sp{sup 2} and sp{sup 3} concentrations is done from X-ray Photoelectron Spectroscopy (XPS). XPS measurements show that DLC films with high quantity of sp{sup 3} hybridisation can be obtained. The discussion and interpretation of these results leads to a better understanding of the relationship between structure and deposition conditions, which, in return, helps us in synthesizing films of desired properties.

  14. Influence of Cr contents and nanograin sizes on microstructure, mechanical and sliding tribological behaviors of hard Cr-diamond-like carbon films.

    PubMed

    Yu, Xiang; Wang, Chengbiao; Hua, Meng; Liu, Yang; Yu, Deyang

    2010-08-01

    The influence of Cr content and nanograin size on the microstructure, the mechanical and sliding tribological behaviors of Cr-containing diamond-like carbon (Cr-DLC) films, deposited on (100) Si substrate by a mid-frequency dual-magnetron system, was explored. The Cr-containing nanoparticles (combining Cr with C) were dispersed in the amorphous DLC matrix while some nanoparticles were transformed into compounds of C/Cr. The incorporation of Cr into Cr-DLC films improved the crystallinity of the Cr-rich nanoparticles and partially converted the nanoparticles to Cr/C phase. The films with Cr content ranging between 5-10 at% and with Cr-containing nanograin sizes in range of 15-27 nm were found to possess higher hardness, lower intrinsic stress, lower coefficient of friction (COF) and wear rate than those of 16-28 at% Cr content and 46-74 nm nanograin sizes. The superhard Cr-DLC film with 8.3 at% Cr and 18.4 nm Cr-containing grain gave the favorable micro-tribological characteristics with COF at micro approximately 0.1 and wear rate at 3.6 x 10(-8) mm3/Nm.

  15. Characteristics of diamond-like carbon film synthesized on AISI 304 austenite stainless steel using plasma immersion ion implantation and deposition

    NASA Astrophysics Data System (ADS)

    Liang, J. H.; Chen, M. H.; Tsai, W. F.; Lee, S. C.; Ai, C. F.

    2007-04-01

    This study examines the characteristics of diamond-like carbon (DLC) film synthesized on AISI 304 austenite stainless steel by means of a hybrid process of plasma immersion ion implantation and deposition (PIII&D) maintained at 60 °C. The former and latter processes under investigation were carried out using methane (0-20 kV) and acetylene (1-2 kV, 0.13-0.40 Pa) plasmas, respectively. Glow discharge spectrometry (GDS), Raman scattering spectroscopy (RSS), atomic force microscopy (AFM), a nano-indentation probe (NIP) and a Rockwell-C hardness tester were employed to characterize, respectively, elemental depth profiles, sp3-to-sp2 ratio, surface morphology, hardness and adhesion strength of the DLC specimen. The results revealed that the mixing layer at the interface generated by plasma immersion ion implantation of methane at a higher voltage could enhance adhesive strength of the DLC film to the substrate. Furthermore, a higher sp3-to-sp2 ratio, a smoother surface, greater hardness, but weaker adhesion strength were obtained for the DLC film synthesized using plasma immersion ion deposition of acetylene at a lower bias voltage or higher gas pressure.

  16. Preparation of Ag-containing diamond-like carbon films on the interior surface of tubes by a combined method of plasma source ion implantation and DC sputtering

    NASA Astrophysics Data System (ADS)

    Hatada, R.; Flege, S.; Bobrich, A.; Ensinger, W.; Dietz, C.; Baba, K.; Sawase, T.; Watamoto, T.; Matsutani, T.

    2014-08-01

    Adhesive diamond-like carbon (DLC) films can be prepared by plasma source ion implantation (PSII), which is also suitable for the treatment of the inner surface of a tube. Incorporation of a metal into the DLC film provides a possibility to change the characteristics of the DLC film. One source for the metal is DC sputtering. In this study PSII and DC sputtering were combined to prepare DLC films containing low concentrations of Ag on the interior surfaces of stainless steel tubes. A DLC film was deposited using a C2H4 plasma with the help of an auxiliary electrode inside of the tube. This electrode was then used as a target for the DC sputtering. A mixture of the gases Ar and C2H4 was used to sputter the silver. By changing the gas flow ratios and process time, the resulting Ag content of the films could be varied. Sample characterizations were performed by X-ray photoelectron spectroscopy, secondary ion mass spectrometry, atomic force microscopy and Raman spectroscopy. Additionally, a ball-on-disk test was performed to investigate the tribological properties of the films. The antibacterial activity was determined using Staphylococcus aureus bacteria.

  17. Tribological properties and thermal stability of hydrogenated, silicon/nitrogen-coincorporated diamond-like carbon films prepared by plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Nakazawa, Hideki; Okuno, Saori; Magara, Kohei; Nakamura, Kazuki; Miura, Soushi; Enta, Yoshiharu

    2016-12-01

    We have deposited hydrogenated, silicon/nitrogen-incorporated diamond-like carbon (Si-N-DLC) films by plasma-enhanced chemical vapor deposition using hexamethyldisilazane [((CH3)3Si)2NH; HMDS] as the Si and N source, and compared the tribological performance and thermal stability of the Si-N-DLC films with those of hydrogenated, Si-incorporated DLC (Si-DLC) films prepared using dimethylsilane [SiH2(CH3)2] as the Si source. The deposited films were annealed at 723-873 K in air atmosphere. The friction coefficients of hydrogenated DLC films after annealing significantly increased at the initial stages of friction tests. On the other hand, the friction coefficients of the Si-N-DLC films deposited at an HMDS flow ratio [HMDS/(HMDS+CH4)] of 2.27% remained low after the annealing even at 873 K. We found that the wear rate of the Si-N-DLC film deposited at 2.27% and -1000 V remained almost unchanged after the annealing at 873 K, whereas that of the Si-DLC film with a similar Si fraction deposited at -1000 V significantly increased after the annealing at 773 K.

  18. A Dynamic Pathway for Stone-Wales Bond Rotation on Carbon Nanotubes through Diamond-Like Bonds

    NASA Technical Reports Server (NTRS)

    Wei, Chen-Yu; Srivastava, Deepak; Cho, Kyeong-Jae; Menon, Madhu

    2003-01-01

    A new lower energy barrier with a two-step pathway of Stone-Wales (SW) ,ond rotation on carbon nanotubes (CNTs) is found through molecular dynamics (MD) simulations of CNTs under tension. The first step involves going over to a stable sp3-like metastable configuration with half rotated and partially tilted C-C bond. The second step involves going over to the fully rotated C-C bond with the formation of a SW defect in the nanotube. The energy barrier for this two-step dynamic pathway is significantly lower than the previously known static barrier for in-plane rotation of the C-C bond on a tensile strained (> 4%) CNT.

  19. Surface modification of diamond-like carbon films with protein via polydopamine inspired coatings

    NASA Astrophysics Data System (ADS)

    Tao, Caihong; Yang, Shengrong; Zhang, Junyan; Wang, Jinqing

    2009-10-01

    In this paper, we report a facile two-step approach to immobilize proteins onto DLC surfaces. The first step was a simple immersion of DLC in a solution of dopamine. Polydopamine was deposited on DLC as a stable anchor to present protein molecules. Then the protein ad-layer was deposited on it. The chemical components of the modified DLC surfaces were characterized by Fourier transform infrared spectra and X-ray photoelectron spectroscopy. The biocompatibility of it was evaluated in vitro by the tetrazolium salt method. And it was indicated that the BSA modified surface had good haemocompatibility properties, and was cytocompatible to PC-12 cells.

  20. Track formation in two amorphous insulators, vitreous silica and diamond like carbon: Experimental observations and description by the inelastic thermal spike model

    NASA Astrophysics Data System (ADS)

    Rotaru, C.; Pawlak, F.; Khalfaoui, N.; Dufour, C.; Perrière, J.; Laurent, A.; Stoquert, J. P.; Lebius, H.; Toulemonde, M.

    2012-02-01

    Vitreous silica thin film (a-SiO 2) and mixed deuterated and hydrogenated amorphous carbon thin film (a-C:D,H), grown or deposited, respectively, on silicon, have been irradiated at GANIL in the MeV/u energy range with ions between C and U in order to reach electronic energy loss between 0.7 and 25 keV/nm. The evolution of Si-O bonds and C-D bonds contents was determined by infrared absorption spectroscopy. Complementary physico-chemical characterization was performed for a-C:D,H using Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA). For a-SiO 2, the band at 1076 cm -1 decreases with the appearance of a band at 1046 cm -1. In the case of the diamond like amorphous carbon, the main effects due to MeV/u ion irradiations are the decrease of sp 3 bonding content and of deuterium relative concentration (D/C atomic ratio) as a function of fluence with the appearance of the sp 1 bond. The cylinder radii in which these physical phenomena are confined can be deduced from a statistical analysis. Using the inelastic thermal spike model (i-TS) these track radii can be described using the electron-phonon mean free path which takes values equal to 3 and 0.9 nm for a-SiO 2 and a-C:D, respectively. Extrapolation to low energy range (˜1 MeV in total or ˜0.02 MeV/u) will be made.

  1. Effects of electrical conductivity of substrate materials on microstructure of diamond-like carbon films prepared by bipolar-type plasma based ion implantation

    NASA Astrophysics Data System (ADS)

    Nakao, S.; Sonoda, T.

    2013-03-01

    Diamond-like carbon (DLC) films are prepared by a bipolar-type plasma based ion implantation, and the structural differences between DLC films deposited on different electrical conductive substrates, i.e., conductive Si wafers and insulating glass plates are examined by Raman spectroscopy and x-ray photo emission spectroscopy (XPS). In the Raman measurements, graphite (G) and disorder (D) peaks are observed for both samples. However, the additional photo luminescence is overlapped on the spectra in the case of on-glass sample. To elucidate the structural difference, the intensity ratio of D to G peak (I(D)/I(G)), G peak position and full width at half maximum (FWHM) are obtained by curve fitting using Gaussian function and linear baseline. It is found that the I(D)/I(G) is lower, G peak position is higher and FWHM of G peak is narrower for on-glass sample than for on-Si sample. According to Robertson [1], lower I(D)/I(G) seems more sp3 C-C bonding in amount for on-glass sample. In contrast, higher G peak position and narrower FWHM of G peak suggest less sp3 C-C bonding in amount for on-glass sample. The results of XPS analysis with C1s spectra reveal that sp3 ratio, i.e., the intensity ratio of sp3/(sp3+sp2) is smaller for on-glass sample than for on-Si sample. The inconsistency of the trend between I(D)/I(G) and other parameters (G peak position and FWHM of G peak) might be caused by the overlap of photo luminescence signal on Raman spectrum as to on-glass sample. From these results, it is considered that sp3 C-C bonding is reduced in amount when using insulating substrate in comparison with conductive substrate.

  2. Nanoscale deformation and fracture mechanics of polycrystalline silicon and diamond-like carbon for MEMS by the AFM/DIC method

    NASA Astrophysics Data System (ADS)

    Cho, Sung Woo

    A method for nanoscale experimental mechanics was developed to address problems in deformation and fracture of micron-scale components in Microelectromechanical Systems (MEMS). Specifically, the effective and local, elastic and fracture behavior of polycrystalline silicon (polysilicon) and tetrahedral amorphous diamond-like carbon (ta-C) were studied using freestanding thin films subject to uniaxial tension. In this method, direct measurements of local deformations were derived from Atomic Force Microscopy (AFM) images in specimen areas varying between 1x2 mum2 and 15x15 mum2 using Digital Image Correlation (DIC) to extract displacements and strains with spatial resolution of 1-2 nm. The effective elastic modulus and Poisson's ratio of polysilicon and ta-C from the Sandia National Laboratories (SUMMiT) were 155 +/- 6 GPa and 0.22 +/- 0.02, and 759 +/- 22 GPa and 0.17 +/- 0.03, respectively. Similarly, the elastic modulus and Poisson's ratio of polysilicon fabricated at MCNC via the Multi-User MEMS Processes (MUMPs) with <110> texture were 164 +/- 7 GPa and 0.22 +/- 0.02, respectively. A second problem studied using the AFM/DIC method was the fracture of polysilicon in the presence of atomically sharp cracks. The effective (macroscopic) Mode-I critical stress intensity factor for polysilicon from different MUMPs runs was 1.00 +/- 0.1 MPa√m, where 0.1 MPa√m was the standard deviation, attributed to local cleavage anisotropy and grain boundary toughening. The variation in the effective critical stress intensity factor and the subcritical crack growth of polysilicon that was spatially recorded and quantified for the first time were the result of the spatial variation of the 4 local stress intensity factor at the crack tip that controlled crack initiation and thus, the overall fracture process. The AFM/DIC method was also applied to determine the minimum size of a polysilicon domain whose effective mechanical behavior could be described by the isotropic elastic

  3. Diamond and diamond-like films for transportation applications

    SciTech Connect

    Perez, J.M.

    1993-01-01

    This section is a compilation of transparency templates which describe the goals of the Office of Transportation Materials (OTM) Tribology Program. The positions of personnel on the OTM are listed. The role and mission of the OTM is reviewed. The purpose of the Tribology Program is stated to be `to obtain industry input on program(s) in tribology/advanced lubricants areas of interest`. The objective addressed here is to identify opportunities for cost effective application of diamond and diamond-like carbon in transportation systems.

  4. Microstructure and property of diamond-like carbon films with Al and Cr co-doping deposited using a hybrid beams system

    NASA Astrophysics Data System (ADS)

    Dai, Wei; Liu, Jingmao; Geng, Dongsen; Guo, Peng; Zheng, Jun; Wang, Qimin

    2016-12-01

    DLC films with weak carbide former Al and carbide former Cr co-doping (Al:Cr-DLC) were deposited by a hybrid beams system comprising an anode-layer linear ion beam source (LIS) and high power impulse magnetron sputtering using a gas mixture of C2H2 and Ar as the precursor. The doped Al and Cr contents were controlled via adjusting the C2H2 fraction in the gas mixture. The composition, microstructure, compressive stress, mechanical properties and tribological behaviors of the Al:Cr-DLC films were researched carefully using X-ray photoelectron spectroscopy, transmission electron microscopy, Raman spectroscopy, stress-tester, nanoindentation and ball-on-plate tribometer as function of the C2H2 fraction. The results show that the Al and Cr contents in the films increased continuously as the C2H2 fraction decreased. The doped Cr atoms preferred to bond with the carbon while the Al atoms mainly existed in metallic state. Structure modulation with alternate multilayer consisted of Al-poor DLC layer and Al-rich DLC layer was found in the films. Those periodic Al-rich DLC layers can effectively release the residual stress of the films. On the other hand, the formation of the carbide component due to Cr incorporation can help to increase the film hardness. Accordingly, the residual stress of the DLC films can be reduced without sacrificing the film hardness though co-doping Al and Cr atoms. Furthermore, it was found that the periodic Al-rich layer can greatly improve the elastic resilience of the DLC films and thus decreases the film friction coefficient and wear rate significantly. However, the existence of the carbide component would cause abrasive wear and thus deteriorate the wear performance of the films.

  5. Nanostructured Carbon Coatings

    DTIC Science & Technology

    2000-01-01

    carbon coatings and explores a very broad range of potentially important carbon nanostructures that may be used in future technologies. A new method ...for the synthesis of nanostructured carbon coatings on the surface of SiC and other metal carbides is described. This method is accomplished through the...With the fall in cost of fullerene powders, this method may become important in the future as a method to produce nanocrystalline diamond free of metal

  6. Process for the formation of wear- and scuff-resistant carbon coatings

    DOEpatents

    Malaczynski, Gerard W.; Qiu, Xiaohong; Mantese, Joseph V.; Elmoursi, Alaa A.; Hamdi, Aboud H.; Wood, Blake P.; Walter, Kevin C.; Nastasi, Michael A.

    1995-01-01

    A process for forming an adherent diamond-like carbon coating on a workpiece of suitable material such as an aluminum alloy is disclosed. The workpiece is successively immersed in different plasma atmospheres and subjected to short duration, high voltage, negative electrical potential pulses or constant negative electrical potentials or the like so as to clean the surface of oxygen atoms, implant carbon atoms into the surface of the alloy to form carbide compounds while codepositing a carbonaceous layer on the surface, bombard and remove the carbonaceous layer, and to thereafter deposit a generally amorphous hydrogen-containing carbon layer on the surface of the article.

  7. Structure, properties, and possible mechanisms of formation of diamond-like phases

    NASA Astrophysics Data System (ADS)

    Belenkov, E. A.; Greshnyakov, V. A.

    2016-10-01

    An analysis was performed for relations between the structural parameters and the properties of 36 carbon diamond-like phases consisting of atoms occupying crystallographically equivalent positions. It was found that the crystal lattices of these phases were in stressed states with respect to the cubic diamond lattice. The density of diamond-like phases, their sublimation energies, bulk moduli, hardnesses, and band gaps depend on the deformation parameters Def and Str. The most stable phases must be phases with minimal parameters Def and Str and also with ring parameter Rng that is most close to the corresponding parameter of cubic diamond. The structures and energy characteristics of fullerites, nanotube bundles, and graphene layers of which diamond-like phases can be obtained as a result of polymerization at high pressures have been calculated.

  8. Synthesis of diamond-like phase from graphite by ultrafast laser driven dynamical compression

    PubMed Central

    Maia, Francisco C. B.; Samad, Ricardo E.; Bettini, Jefferson; Freitas, Raul O.; Vieira Junior, Nilson D.; Souza-Neto, Narcizo M.

    2015-01-01

    Rapid variations of the environmental energy caused by ultrashort laser pulses have induced phase transitions in carbon allotropes, therefore bringing the promise of revealing new carbon phases. Here, by exposing polycrystalline graphite to 25 fs laser pulses at 4 J/cm2 fluence under standard air atmosphere, we demonstrated the synthesis of translucent micrometer-sized structures carrying diamond-like and onion-like carbon phases. Texturized domains of the diamond phase were also identified. Concerning different synthesized carbon forms, pulse superposition and singularities of the thermodynamical process, we pinpoint the synthesis mechanism by the laser-induced subsequent products energetically evolving to attain the diamond-like phase. PMID:26149413

  9. Status and Applications of Diamond and Diamond-Like Materials: An Emerging Technology

    DTIC Science & Technology

    1990-04-30

    solar -blind detectors. * Modulated structures incorporating layers of BN and diamond, for example, to develop materials that are harder and/or tougher...hundredfold increase in power capability over silicon transistors. e Solar -blind detectors, which take advantage of the large energy gap (greater than...Some success has already been achieved, for example, in applying diamond-like coatings to ZnS and ZnSe windows using a Ge-C intermediate layer . " Anti

  10. LARGE AREA FILTERED ARC DEPOSITION OF CARBON AND BORON BASED HARD COATINGS

    SciTech Connect

    Bhattacharya, Rabi S.

    2003-12-05

    This document is a final report covering work performed under Contract No. DE-FG02-99ER82911 from the Department of Energy under a SBIR Phase II Program. Wear resistant, hard coatings can play a vital role in many engineering applications. The primary goal of this project was to develop coatings containing boron and carbon with hardness greater than 30 GPa and evaluate these coatings for machining applications. UES has developed a number of carbon and boron containing coatings with hardness in the range of 34 to 65 GPa using a combination of filtered cathodic arc and magnetron sputtering. The boron containing coatings were based on TiB2, TiBN, and TiBCN, while the carbon containing coatings ere TiC+C and hydrogen free diamond-like-carbon. Machining tests were performed with single and multilayer coated tools. The turning and milling tests were run at TechSolve Inc., under a subcontract at Ohio State University. Significant increases in tool lives were realized in end milling of H-13 die steel (8X) and titanium alloy (80%) using the TiBN coating. A multilayer TiBN/TiN performed the best in end-milling of highly abrasive Al-Si alloys. A 40% increase in life over the TiAlN benchmark coating was found. Further evaluations of these coatings with commercialization partners are currently in progress.

  11. Fatigue resistant carbon coatings for rolling/sliding contacts

    SciTech Connect

    Singh, Harpal; Ramirez, Giovanni; Eryilmaz, Osman; Greco, Aaron; Doll, Gary; Erdemir, Ali

    2016-06-01

    The growing demands for renewable energy production have recently resulted in a significant increase in wind plant installation. Field data from these plants show that wind turbines suffer from costly repair, maintenance and high failure rates. Often times the reliability issues are linked with tribological components used in wind turbine drivetrains. The primary failure modes in bearings and gears are associated with micropitting, wear, brinelling, scuffing, smearing and macropitting all of which occur at or near the surface. Accordingly, a variety of surface engineering approaches are currently being considered to alter the near surface properties of such bearings and gears to prevent these tribological failures. In the present work, we have evaluated the tribological performance of compliant highly hydrogenated diamond like carbon coating developed at Argonne National Laboratory, under mixed rolling/sliding contact conditions for wind turbine drivetrain components. The coating was deposited on AISI 52100 steel specimens using a magnetron sputter deposition system. The experiments were performed on a PCS Micro-Pitting-Rig (MPR) with four material pairs at 1.79 GPa contact stress, 40% slide to roll ratio and in polyalphaolefin (PAO4) basestock oil (to ensure extreme boundary conditions). The post-test analysis was performed using optical microscopy, surface profilometry, and Raman spectroscopy. The results obtained show a potential for these coatings in sliding/rolling contact applications as no failures were observed with coated specimens even after 100 million cycles compared to uncoated pair in which they failed after 32 million cycles, under the given test conditions.

  12. Application of amorphous carbon based materials as antireflective coatings on crystalline silicon solar cells

    NASA Astrophysics Data System (ADS)

    da Silva, D. S.; Côrtes, A. D. S.; Oliveira, M. H.; Motta, E. F.; Viana, G. A.; Mei, P. R.; Marques, F. C.

    2011-08-01

    We report on the investigation of the potential application of different forms of amorphous carbon (a-C and a-C:H) as an antireflective coating for crystalline silicon solar cells. Polymeric-like carbon (PLC) and hydrogenated diamond-like carbon films were deposited by plasma enhanced chemical vapor deposition. Tetrahedral amorphous carbon (ta-C) was deposited by the filtered cathodic vacuum arc technique. Those three different amorphous carbon structures were individually applied as single antireflective coatings on conventional (polished and texturized) p-n junction crystalline silicon solar cells. Due to their optical properties, good results were also obtained for double-layer antireflective coatings based on PLC or ta-C films combined with different materials. The results are compared with a conventional tin dioxide (SnO2) single-layer antireflective coating and zinc sulfide/magnesium fluoride (ZnS/MgF2) double-layer antireflective coatings. An increase of 23.7% in the short-circuit current density, Jsc, was obtained using PLC as an antireflective coating and 31.7% was achieved using a double-layer of PLC with a layer of magnesium fluoride (MgF2). An additional increase of 10.8% was obtained in texturized silicon, representing a total increase (texturization + double-layer) of about 40% in the short-circuit current density. The potential use of these materials are critically addressed considering their refractive index, optical bandgap, absorption coefficient, hardness, chemical inertness, and mechanical stability.

  13. Tribological performance of hard carbon coatings on 440C bearing steel

    NASA Astrophysics Data System (ADS)

    Kustas, Frank N.; Misra, Mohan S.; Shepard, Donald F.; Froechtenigt, Joseph F.

    1990-12-01

    Hard carbon coating such as diamond and diamond-like c :bon (also referred to as amorphous carbon) have received considerable attention for tribological applications due to their high hardness high modulus and desirable surface properties. Unfortunately most of the deposition techniques induce high substrate temperatures that temper traditional bearing steels and reduce the substrate load-carrying capability. Therefore to effectively use these desirable coatings a lower temperature deposition technique is required. Ion beam deposition offers essentially ambient temperature conditions accurate control ofprocess parameters and good coating-substrate adhesion. To use these attributes a test program was initiated to deposit mass analyzed high purity carbon and methane ions onto molybdenum and 440C bearing steel for subsequent characterization by Raman spectroscopy and friction-wear tests. Preliminary results for a coating deposited from a CO source showed an amorphous carbon/microcrystalline graphite structure which exhibited very high microhardness and a 3-fold reduction in coefficient of friction for unlubricated tests compared to untreated 440C steel. In addition incrementally increasing the applied load up to a factor of 5 resulted in progressively lower coefficients of friction only a minor increase (about 11) in the wear scar depth and no dramatic coating delamination or damage. Therefore an amorphous carbon/graphite coating applied to 440C steel at ambient temperature exhibits solid lubricating film characteristics with extremely high load-carrying capability. *Work performed under Martin Marietta Independent Research and Development Project D-8 1R Materials Technology. 116

  14. Thermoplastic coating of carbon fibers

    NASA Technical Reports Server (NTRS)

    Edie, D. D.; Lickfield, G. C.; Allen, L. E.; Mccollum, J. R.

    1989-01-01

    A continuous powder coating system was developed for coating carbon fiber with LaRC-TPI (Langley Research Center-Thermoplastic Polyimide), a high-temperature thermoplastic polymide invented by NASA-Langley. The coating line developed used a pneumatic fiber spreader to separate the individual fibers. The polymer was applied within a recirculating powder coating chamber then melted using a combination of direct electrical resistance and convective heating to make it adhere to the fiber tow. The tension and speed of the line were controlled with a dancer arm and an electrically driven fiber wind-up and wind-off. The effects of heating during the coating process on the flexibility of the prepreg produced were investigated. The uniformity with which the fiber tow could be coated with polymer also was examined. Composite specimens were fabricated from the prepreg and tested to determine optimum process conditions. The study showed that a very uniform and flexible prepeg with up to 50 percent by volume polymer could be produced with this powder coating system. The coating line minimized powder loss and produced prepeg in lengths of up to 300 m. The fiber spreading was found to have a major effect on the coating uniformity and flexibility. Though test results showed low composite tensile strengths, analysis of fracture surfaces under scanning electron microscope indicated that fiber/matrix adhesion was adequate.

  15. Coating Carbon Fibers With Platinum

    NASA Technical Reports Server (NTRS)

    Effinger, Michael R.; Duncan, Peter; Coupland, Duncan; Rigali, Mark J.

    2007-01-01

    A process for coating carbon fibers with platinum has been developed. The process may also be adaptable to coating carbon fibers with other noble and refractory metals, including rhenium and iridium. The coated carbon fibers would be used as ingredients of matrix/fiber composite materials that would resist oxidation at high temperatures. The metal coats would contribute to oxidation resistance by keeping atmospheric oxygen away from fibers when cracks form in the matrices. Other processes that have been used to coat carbon fibers with metals have significant disadvantages: Metal-vapor deposition processes yield coats that are nonuniform along both the lengths and the circumferences of the fibers. The electrical resistivities of carbon fibers are too high to be compatible with electrolytic processes. Metal/organic vapor deposition entails the use of expensive starting materials, it may be necessary to use a furnace, and the starting materials and/or materials generated in the process may be hazardous. The present process does not have these disadvantages. It yields uniform, nonporous coats and is relatively inexpensive. The process can be summarized as one of pretreatment followed by electroless deposition. The process consists of the following steps: The surfaces of the fiber are activated by deposition of palladium crystallites from a solution. The surface-activated fibers are immersed in a solution that contains platinum. A reducing agent is used to supply electrons to effect a chemical reduction in situ. The chemical reduction displaces the platinum from the solution. The displaced platinum becomes deposited on the fibers. Each platinum atom that has been deposited acts as a catalytic site for the deposition of another platinum atom. Hence, the deposition process can also be characterized as autocatalytic. The thickness of the deposited metal can be tailored via the duration of immersion and the chemical activity of the solution.

  16. Bacterial adherence on fluorinated carbon based coatings deposited on polyethylene surfaces

    NASA Astrophysics Data System (ADS)

    Terriza, A.; Del Prado, G.; Ortiz Pérez, A.; Martínez, M. J.; Puértolas, J. A.; Molina Manso, D.; González-Elipe, A. R.; Yubero, F.; Gómez Barrena, E.; Esteban, J.

    2010-11-01

    Development of intrinsically antibacterial surfaces is of key importance in the context of prostheses used in orthopaedic surgery. In this work we present a thorough study of several plasma based coatings that may be used with this functionality: diamond like carbon (DLC), fluorine doped DLC (F-DLC) and a high fluorine content carbon-fluor polymer (CFX). The study correlates the surface chemistry and hydrophobicity of the coating surfaces with their antibacterial performance. The coatings were deposited by RF-plasma assisted deposition at room temperature on ultra high molecular weight polyethylene (UHMWPE) samples. Fluorine content and relative amount of C-C and C-F bond types was monitored by X-ray photoelectron spectroscopy and hydrophobicity by water contact angle measurements. Adherence of Staphylococcus aureus and Staphylococcus epidermidis to non-coated and coated UHMWPE samples was evaluated. Comparisons of the adherence performance were evaluated using a paired t test (two materials) and a Kruskall Wallis test (all the materials). S. aureus was statistically significant (p< 0.001) less adherent to DLC and F -DLC surfaces than S. epidermidis. Both bacteria showed reduction of adherence on DLC/UHMWPE. For S. aureus, reduction of bacterial adherence on F-DLC/UHMWPE was statistically significant respect to all other materials.

  17. Method for simultaneously coating a plurality of filaments

    DOEpatents

    Miller, P.A.; Pochan, P.D.; Siegal, M.P.; Dominguez, F.

    1995-07-11

    Methods and apparatuses are disclosed for coating materials, and the products and compositions produced thereby. Substances, such as diamond or diamond-like carbon, are deposited onto materials, such as a filament or a plurality of filaments simultaneously, using one or more cylindrical, inductively coupled, resonator plasma reactors. 3 figs.

  18. Method for simultaneously coating a plurality of filaments

    DOEpatents

    Miller, Paul A.; Pochan, Paul D.; Siegal, Michael P.; Dominguez, Frank

    1995-01-01

    Methods and apparatuses for coating materials, and the products and compositions produced thereby. Substances, such as diamond or diamond-like carbon, are deposited onto materials, such as a filament or a plurality of filaments simultaneously, using one or more cylindrical, inductively coupled, resonator plasma reactors.

  19. Method of depositing a carbon film on a substrate and products obtained thereby

    SciTech Connect

    Lewin, G.; Nir, D.

    1984-12-04

    There is disclosed a method for depositing a diamond or diamond-like carbon film on at least one substrate employing a hydrocarbon gas and at least one gas which preferentially removes by chemical sputtering other forms of carbon, especially graphite from said film to thereby obtain useful carbon film coated products.

  20. Coated carbon nanotube array electrodes

    DOEpatents

    Ren, Zhifeng; Wen, Jian; Chen, Jinghua; Huang, Zhongping; Wang, Dezhi

    2008-10-28

    The present invention provides conductive carbon nanotube (CNT) electrode materials comprising aligned CNT substrates coated with an electrically conducting polymer, and the fabrication of electrodes for use in high performance electrical energy storage devices. In particular, the present invention provides conductive CNTs electrode material whose electrical properties render them especially suitable for use in high efficiency rechargeable batteries. The present invention also provides methods for obtaining surface modified conductive CNT electrode materials comprising an array of individual linear, aligned CNTs having a uniform surface coating of an electrically conductive polymer such as polypyrrole, and their use in electrical energy storage devices.

  1. Coated carbon nanotube array electrodes

    DOEpatents

    Ren, Zhifeng; Wen, Jian; Chen, Jinghua; Huang, Zhongping; Wang, Dezhi

    2006-12-12

    The present invention provides conductive carbon nanotube (CNT) electrode materials comprising aligned CNT substrates coated with an electrically conducting polymer, and the fabrication of electrodes for use in high performance electrical energy storage devices. In particular, the present invention provides conductive CNTs electrode material whose electrical properties render them especially suitable for use in high efficiency rechargeable batteries. The present invention also provides methods for obtaining surface modified conductive CNT electrode materials comprising an array of individual linear, aligned CNTs having a uniform surface coating of an electrically conductive polymer such as polypyrrole, and their use in electrical energy storage devices.

  2. Laser ablated hard coating for microtools

    DOEpatents

    McLean, W. II; Balooch, M.; Siekhaus, W.J.

    1998-05-05

    Wear-resistant coatings composed of laser ablated hard carbon films, are deposited by pulsed laser ablation using visible light, on instruments such as microscope tips and micro-surgical tools. Hard carbon, known as diamond-like carbon (DLC), films produced by pulsed laser ablation using visible light enhances the abrasion resistance, wear characteristics, and lifetimes of small tools or instruments, such as small, sharp silicon tips used in atomic probe microscopy without significantly affecting the sharpness or size of these devices. For example, a 10--20 nm layer of diamond-like carbon on a standard silicon atomic force microscope (AFM) tip, enables the useful operating life of the tip to be increased by at least twofold. Moreover, the low inherent friction coefficient of the DLC coating leads to higher resolution for AFM tips operating in the contact mode. 12 figs.

  3. Laser ablated hard coating for microtools

    DOEpatents

    McLean, II, William; Balooch, Mehdi; Siekhaus, Wigbert J.

    1998-05-05

    Wear-resistant coatings composed of laser ablated hard carbon films, are deposited by pulsed laser ablation using visible light, on instruments such as microscope tips and micro-surgical tools. Hard carbon, known as diamond-like carbon (DLC), films produced by pulsed laser ablation using visible light enhances the abrasion resistance, wear characteristics, and lifetimes of small tools or instruments, such as small, sharp silicon tips used in atomic probe microscopy without significantly affecting the sharpness or size of these devices. For example, a 10-20 nm layer of diamond-like carbon on a standard silicon atomic force microscope (AFM) tip, enables the useful operating life of the tip to be increased by at least twofold. Moreover, the low inherent friction coefficient of the DLC coating leads to higher resolution for AFM tips operating in the contact mode.

  4. Pyrolytic carbon coated black silicon

    PubMed Central

    Shah, Ali; Stenberg, Petri; Karvonen, Lasse; Ali, Rizwan; Honkanen, Seppo; Lipsanen, Harri; Peyghambarian, N.; Kuittinen, Markku; Svirko, Yuri; Kaplas, Tommi

    2016-01-01

    Carbon is the most well-known black material in the history of man. Throughout the centuries, carbon has been used as a black material for paintings, camouflage, and optics. Although, the techniques to make other black surfaces have evolved and become more sophisticated with time, carbon still remains one of the best black materials. Another well-known black surface is black silicon, reflecting less than 0.5% of incident light in visible spectral range but becomes a highly reflecting surface in wavelengths above 1000 nm. On the other hand, carbon absorbs at those and longer wavelengths. Thus, it is possible to combine black silicon with carbon to create an artificial material with very low reflectivity over a wide spectral range. Here we report our results on coating conformally black silicon substrate with amorphous pyrolytic carbon. We present a superior black surface with reflectance of light less than 0.5% in the spectral range of 350 nm to 2000 nm. PMID:27174890

  5. Status and applications of diamond and diamond-like materials: An emerging technology

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Recent discoveries that make possible the growth of crystalline diamond by chemical vapor deposition offer the potential for a wide variety of new applications. This report takes a broad look at the state of the technology following from these discoveries in relation to other allied materials, such as high-pressure diamond and cubic boron nitride. Most of the potential defense, space, and commercial applications are related to diamond's hardness, but some utilize other aspects such as optical or electronic properties. The growth processes are reviewed, and techniques for characterizing the resulting materials' properties are discussed. Crystalline diamond is emphasized, but other diamond-like materials (silicon carbide, amorphous carbon containing hydrogen) are also examined. Scientific, technical, and economic problem areas that could impede the rapid exploitation of these materials are identified. Recommendations are presented covering broad areas of research and development.

  6. Carbon nanotube coatings as chemical absorbers

    DOEpatents

    Tillotson, Thomas M.; Andresen, Brian D.; Alcaraz, Armando

    2004-06-15

    Airborne or aqueous organic compound collection using carbon nanotubes. Exposure of carbon nanotube-coated disks to controlled atmospheres of chemical warefare (CW)-related compounds provide superior extraction and retention efficiencies compared to commercially available airborne organic compound collectors. For example, the carbon nanotube-coated collectors were four (4) times more efficient toward concentrating dimethylmethyl-phosphonate (DMMP), a CW surrogate, than Carboxen, the optimized carbonized polymer for CW-related vapor collections. In addition to DMMP, the carbon nanotube-coated material possesses high collection efficiencies for the CW-related compounds diisopropylaminoethanol (DIEA), and diisopropylmethylphosphonate (DIMP).

  7. Silver-doped nanocomposite carbon coatings (Ag-DLC) for biomedical applications - Physiochemical and biological evaluation

    NASA Astrophysics Data System (ADS)

    Bociaga, Dorota; Komorowski, Piotr; Batory, Damian; Szymanski, Witold; Olejnik, Anna; Jastrzebski, Krzysztof; Jakubowski, Witold

    2015-11-01

    The formation of bacteria biofilm on the surface of medical products is a major clinical issue nowadays. Highly adaptive ability of bacteria to colonize the surface of biomaterials causes a lot of infections. This study evaluates samples of the AISI 316 LVM with special nanocomposite silver-doped (by means of ion implantation) diamond-like carbon (DLC) coating prepared by hybrid RF/MS PACVD (radio frequency/magnetron sputtering plasma assisted chemical vapour deposition) deposition technique in order to improve the physicochemical and biological properties of biomaterials and add new features such as antibacterial properties. The aim of the following work was to evaluate antimicrobial efficacy and biocompatibility of gradient a-C:H/Ti + Ag coatings in relation to the physiochemical properties of the surface and chemical composition of coating. For this purpose, samples were tested in live/dead test using two cell strains: human endothelial cells (Ea.hy926) and osteoblasts-like cells (Saos-2). For testing bactericidal activity of the coatings, an exponential growth phase of Escherichia coli strain DH5α was used as a model microorganism. Surface condition and its physicochemical properties were investigated using SEM, AFM and XPS. Examined coatings showed a uniformity of silver ions distribution in the amorphous DLC matrix, good biocompatibility in contact with mammalian cells and an increased level of bactericidal properties. What is more, considering very good mechanical parameters of these Ag including gradient a-C:H/Ti coatings, they constitute an excellent material for biomedical application in e.g. orthopedics or dentistry.

  8. Superhydrophobic conductive carbon nanotube coatings for steel.

    PubMed

    Sethi, Sunny; Dhinojwala, Ali

    2009-04-21

    We report the synthesis of superhydrophobic coatings for steel using carbon nanotube (CNT)-mesh structures. The CNT coating maintains its structural integrity and superhydrophobicity even after exposure to extreme thermal stresses and has excellent thermal and electrical properties. The coating can also be reinforced by optimally impregnating the CNT-mesh structure with cross-linked polymers without significantly compromising on superhydrophobicity and electrical conductivity. These superhydrophobic conductive coatings on steel, which is an important structural material, open up possibilities for many new applications in the areas of heat transfer, solar panels, transport of fluids, nonwetting and nonfouling surfaces, temperature resilient coatings, composites, water-walking robots, and naval applications.

  9. Pyrolytic carbon-coated nuclear fuel

    DOEpatents

    Lindemer, Terrence B.; Long, Jr., Ernest L.; Beatty, Ronald L.

    1978-01-01

    An improved nuclear fuel kernel having at least one pyrolytic carbon coating and a silicon carbon layer is provided in which extensive interaction of fission product lanthanides with the silicon carbon layer is avoided by providing sufficient UO.sub.2 to maintain the lanthanides as oxides during in-reactor use of said fuel.

  10. Development of improved coating for advanced carbon-carbon components

    NASA Technical Reports Server (NTRS)

    Yamaki, Y. R.; Brown, J. J.

    1984-01-01

    Reaction sintered silicon nitride (RSSN) was studied as a substitute coating material on the carbon-carbon material (RCC) presently used as a heat shield on the space shuttle, and on advanced carbon-carbon (ACC), a later development. On RCC, RSSN showed potential in a 538 C (1000 F) screening test in which silicon carbide coated material exhibits its highest oxidation rate; RSSN afforded less protection to ACC because of a larger thermal expansion mismatch. Organosilicon densification and metallic silicon sealing methods were studied as means of further increasing the oxidation resistance of the coating, and some improvement was noted when these methods were employed.

  11. Process to minimize cracking of pyrolytic carbon coatings

    DOEpatents

    Lackey, Jr., Walter J.; Sease, John D.

    1978-01-01

    Carbon-coated microspheroids useful as fuels in nuclear reactors are produced with a low percentage of cracked coatings and are imparted increased strength and mechanical stability characteristics by annealing immediately after the carbon coating processes.

  12. Tests Of Protective Coats For Carbon Steel

    NASA Technical Reports Server (NTRS)

    Macdowell, Louis G., III

    1995-01-01

    Report describes laboratory and field tests of candidate paints (primers, tie coats, and topcoats) for use in protecting carbon-steel structures against corrosion in seaside environment at Kennedy Space Center. Coating materials selected because of utility in preventing corrosion, also on basis of legal requirements, imposed in several urban areas, for reduction of volatile organic contents.

  13. [Hydroxyapatite bioactive coating on carbon/carbon composites].

    PubMed

    Sui, Jinling; Li, Musen; Lü, Yupeng; Bai, Yunqiang

    2005-04-01

    A simple plasma spraying method was employed in coating hydroxyapaptite (HA) on to carbon/carbon composites (C/C composites). The morphology of the coating was examined under scanning electron microscope (SEM). The phase constitutions of the HA coating were determined by X-ray diffractometer (XRD). The shear strength of the HA coating-C/C composite substrates was detected. A hydroxyapatite coating with rough surface was observed. A considerable amount of amorphous phase appeared as a result from the coating process, which could be transformed into the morphous phase crystalline HA after subsequent heat treatment. The shear strength between the HA coating and C/C composite substrates was 7.15 MPa.

  14. Apparatus for producing carbon-coated nanoparticles and carbon nanospheres

    DOEpatents

    Perry, W. Lee; Weigle, John C.; Phillips, Jonathan

    2015-10-20

    An apparatus for producing carbon-coated nano- or micron-scale particles comprising a container for entraining particles in an aerosol gas, providing an inlet for carbon-containing gas, providing an inlet for plasma gas, a proximate torch for mixing the aerosol gas, the carbon-containing gas, and the plasma gas, bombarding the mixed gases with microwaves, and providing a collection device for gathering the resulting carbon-coated nano- or micron-scale particles. Also disclosed is a method and apparatus for making hollow carbon nano- or micro-scale spheres.

  15. High-Melt Carbon-Carbon Coating for Nozzle Extensions

    NASA Technical Reports Server (NTRS)

    Thompson, James

    2015-01-01

    Carbon-Carbon Advanced Technologies, Inc. (C-CAT), has developed a high-melt coating for use in nozzle extensions in next-generation spacecraft. The coating is composed primarily of carbon-carbon, a carbon-fiber and carbon-matrix composite material that has gained a spaceworthy reputation due to its ability to withstand ultrahigh temperatures. C-CAT's high-melt coating embeds hafnium carbide (HfC) and zirconium diboride (ZrB2) within the outer layers of a carbon-carbon structure. The coating demonstrated enhanced high-temperature durability and suffered no erosion during a test in NASA's Arc Jet Complex. (Test parameters: stagnation heat flux=198 BTD/sq ft-sec; pressure=.265 atm; temperature=3,100 F; four cycles totaling 28 minutes) In Phase I of the project, C-CAT successfully demonstrated large-scale manufacturability with a 40-inch cylinder representing the end of a nozzle extension and a 16-inch flanged cylinder representing the attach flange of a nozzle extension. These demonstrators were manufactured without spalling or delaminations. In Phase II, C-CAT worked with engine designers to develop a nozzle extension stub skirt interfaced with an Aerojet Rocketdyne RL10 engine. All objectives for Phase II were successfully met. Additional nonengine applications for the coating include thermal protection systems (TPS) for next-generation spacecraft and hypersonic aircraft.

  16. Properties of carbon fibers with various coatings

    NASA Technical Reports Server (NTRS)

    Seegel, V.; Mcmahon, P.

    1983-01-01

    It is shown that all high modulus carbon fibers are durable with respect to thermal oxidation in air. Among the more widely used and economical materials with low modulus, Celion displays particularly good oxidative durability at high temperatures. This contrast to other materials is due to the low content of Natrium and Kalium in Celion carbon fibers. It is also noted that improved characteristics are attained in Celion carbon fiber/polyimide systems when fibers are used with high temperature resistant polyimide coatings.

  17. Gradient titanium and silver based carbon coatings deposited on AISI316L

    NASA Astrophysics Data System (ADS)

    Batory, Damian; Reczulska, Malgorzata Czerniak-; Kolodziejczyk, Lukasz; Szymanski, Witold

    2013-06-01

    The constantly growing market for medical implants and devices caused mainly due to a lack of proper attention attached to the physical condition as well as extreme sports and increased elderly population creates the need of new biocompatible biomaterials with controlled bioactivity and certain useful properties. According to many literature reports, regarding the modifications of variety of different biomaterials using the surface engineering techniques and their biological and physicochemical examination results, the most promising material for great spectra of medical applications seem to be carbon layers. Another issue is the interaction between the implant material and surrounding tissue. In particular cases this interface area is directly exposed to air. Abovementioned concern occurs mainly in case of the external fixations, thus they are more vulnerable to infection. Therefore a crucial role has the inhibition of bacterial adhesion that may prevent implant-associated infections, occurrence of other numerous complications and in particular cases rejection of the implant. For this reason additional features of carbon coatings like antibacterial properties seem to be desired and justified. Silver doped diamond-like carbon coatings with different Ag concentrations were prepared by hybrid RF PACVD/MS (Radio Frequency Plasma Assisted Chemical Vapor Deposition/Magnetron Sputtering) deposition technique. Physicochemical parameters like chemical composition, morphology and surface topography, hardness and adhesion were determined. Examined layers showed a uniform distribution of silver in the amorphous DLC matrix, high value of H/E ratio, good adhesion and beneficial topography which make them a perfect material for medical applications e.g. modification of implants for the external fixations.

  18. Coating for gasifiable carbon-graphite fibers

    NASA Technical Reports Server (NTRS)

    Harper-Tervet, Jan (Inventor); Dowler, Warren L. (Inventor); Yen, Shiao-Ping S. (Inventor); Mueller, William A. (Inventor)

    1982-01-01

    A thin, uniform, firmly adherent coating of metal gasification catalyst is applied to a carbon-graphite fiber by first coating the fiber with a film-forming polymer containing functional moieties capable of reaction with the catalytic metal ions. Multivalent metal cations such as calcium cross-link the polymer such as a polyacrylic acid to insolubilize the film by forming catalytic metal macro-salt links between adjacent polymer chains. The coated fibers are used as reinforcement for resin composites and will gasify upon combustion without evolving conductive airborne fragments.

  19. Innovative Superhard Materials and Sustainable Coatings for Advanced Manufacturing

    NASA Astrophysics Data System (ADS)

    Lee, Jay; Novikov, Nikolay

    The book contains the results of the latest achievements of leading researchers from 9 countries in the field of diamond and diamond-like carbon, cubic boron nitride and other superhard materials; high-density engineering ceramics; high pressure-high temperature technique; computer-aided modeling; diamond, cubic boron nitride, ceramic and cemented carbide tools; development, production and applications of nanostructured materials; films and wear-resistant coating; methods for quality control of tool materials and tools.

  20. Identification of the diamond-like B-C phase by confocal Raman spectroscopy.

    PubMed

    Zinin, P V; Kudryashov, I; Konishi, N; Ming, L C; Solozhenko, V L; Sharma, S K

    2005-08-01

    The new diamond-like B-C phase was obtained from the graphite-like BC phase in a laser-heated diamond anvil cell at high temperature 2230+/-140 K and high pressure 45 GPa. Raman spectra of the new phase measured at ambient conditions revealed a peak at 1315 cm(-1), which was attributed to longitudinal-optical (LO) mode. The X-Y Raman mapping was used to investigate spatial distribution of the diamond-like phases and was shown to be a powerful tool in studying the sp(2)-to-sp(3) phase transformations occurring in the diamond cell under high temperature and high pressure.

  1. Antioxidative protective coatings for carbon materials

    SciTech Connect

    Kravetskii, G.A.; Kostikov, V.I.; Demin, A.V.; Rodionova, V.V.

    1995-12-01

    A widespread use of carbon-carbon and carbon-ceramic materials (CCM) in the aerospace industry, metallurgy (crucibles for melting metals) and electrical engineering is limited because of the need for protecting CCM parts against oxidation at service temperatures above 500 to 700{degrees}C. At temperatures up to 1300-1400{degrees}C, the problem can be solved by volume siliconizing CCM parts, impregnating C-C substrates with organosilicon compounds or gas-phase depositing (CVD process) silicon-containing compounds (SiC or Si{sub 3}N{sub 4}). For CCM parts to be used at temperatures above 1500{degrees}C in oxidative environments (space structures; aircraft gas-turbine engine components in contact with a hot gas; crucibles for melting metals), the following techniques are being devised to apply protective coatings, as evident from a patent literature analysis: (1) Application of SiC coatings onto the surface of graphite or C-C parts by the CVD or CVR methods; such coatings can be quite efficient for parts operating short time at temperatures up to 2000{degrees}C, for example in rocket engines; (2) SiC coatings applied onto the surface of large-sized or intricately-shaped parts frequently experience cracking; this necessitates the application of multilayered or multicomponent coatings (by subsequent impregnation with various silicate compositions, covering with glass or glass-like compositions to {open_quotes}heal{close_quotes} cracks; applying surface oxide or silicate coatings); (3) Application on the surface of CCM parts of refractory, self-healing-in use coatings containing refractory borides and silicides; to this end the CVD method and plasma spraying in controlled atmospheres are employed. Given below are results of the investigations conducted at NIIGRA-FIT in the above-mentioned directions with the use of the slip-casting technology.

  2. Functional Carbon Nanocomposite, Optoelectronic, and Catalytic Coatings

    NASA Astrophysics Data System (ADS)

    Liang, Yu Teng

    Over the past couple decades, fundamental research into carbon nanomaterials has produced a steady stream of groundbreaking physical science. Their record setting mechanical strength, chemical stability, and optoelectronic performance have fueled many optimistic claims regarding the breadth and pace of carbon nanotube and graphene integration. However, present synthetic, processing, and economic constraints have precluded these materials from many practical device applications. To overcome these limitations, novel synthetic techniques, processing methodologies, device geometries, and mechanistic insight were developed in this dissertation. The resulting advancements in material production and composite device performance have brought carbon nanomaterials ever closer to commercial implementation. For improved materials processing, vacuum co-deposition was first demonstrated as viable technique for forming carbon nanocomposite films without property distorting covalent modifications. Co-deposited nanoparticle, carbon nanotube, and graphene composite films enabled rapid device prototyping and compositional optimization. Cellulosic polymer stabilizers were then shown to be highly effective carbon nanomaterial dispersants, improving graphene production yields by two orders of magnitude in common organic solvents. By exploiting polarity interactions, iterative solvent exchange was used to further increase carbon nanomaterial dispersion concentrations by an additional order of magnitude, yielding concentrated inks. On top of their low causticity, these cellulosic nanomaterial inks have highly tunable viscosities, excellent film forming capacity, and outstanding thermal stability. These processing characteristics enable the efficient scaling of carbon nanomaterial coatings and device production using existing roll-to-roll fabrication techniques. Utilizing these process improvements, high-performance gas sensing, energy storage, transparent conductor, and photocatalytic

  3. Carbon coatings on polymers and their biocompatibility

    NASA Astrophysics Data System (ADS)

    Hubáček, T.; Siegel, J.; Khalili, R.; Slepičková-Kasálková, N.; Švorčík, V.

    2013-06-01

    In this paper we modified the surface properties of polymer foils (polyethyleneterephthalate (PET) and polytetrafluoroethylene (PTFE)) by flash evaporation of carbon layers (C-layers). Adhesion and proliferation of vascular smooth muscle cells (VSMC) on carbon coated PTFE and PET were studied in vitro. Chemical composition of deposited C-layers was determined by Raman spectroscopy, surface contact angle was measured by goniometry. Surface morphology of carbon coated samples was studied using atomic force microscopy. Electrical properties of deposited C-layers were determined by measuring its sheet resistance. It was found that the carbon deposition leads to a decrease of surface roughness of PTFE and PET and to a significant increase of sample wettability. Electrical resistance and wettability of deposited C-layers depends significantly on both the thickness of C-layer and the type of polymeric substrate used. It was found that maximal stimulation of the VSMC (adhesion and proliferation) on carbon coated polymers depends on the surface roughness and contact angle of cell carriers used.

  4. Fluorinating hexagonal boron nitride into diamond-like nanofilms with tunable band gap and ferromagnetism.

    PubMed

    Zhang, Zhuhua; Zeng, Xiao Cheng; Guo, Wanlin

    2011-09-21

    Cubic boron nitride (c-BN) possesses a number of extreme properties rivaling or surpassing those of diamond. Especially, owing to the high chemical stability, c-BN is desired for fabricating electronic devices that can stand up to harsh environments. However, realization of c-BN-based functional devices is still a challenging task due largely to the subtlety in the preparation of high-quality c-BN films with uniform thickness and controllable properties. Here, we present a simple synthetic strategy by surface fluorination of few-layered hexagonal boron nitride (h-BN) sheets to produce thermodynamically favorable F-terminated c-BN nanofilms with an embedded N-N bond layer and strong inbuilt electric polarization. Due to these specific features, the fluorinated c-BN nanofilms have controllable band gap by thickness or inbuilt and applied electric fields. Especially, the produced nanofilms can be tuned into substantial ferromagnetism through electron doping within a reasonable level. The electron-doping-induced deformation ratio of the c-BN nanofilms is found to be 1 order of magnitude higher than those of carbon nanotubes and graphene. At sufficient high doping levels, the nanofilm can be cleaved peculiarly along the N-N bond layer into diamond-like BN films. As the proposed synthesis strategy of the fluorinated c-BN nanofilms is well within the reach of current technologies, our results represent an extremely cost-effective approach for producing high-quality c-BN nanofilms with tunable electronic, magnetic, and electromechanical properties for versatile applications.

  5. Preparation of Chameleon Coatings for Space and Ambient Environments (Preprint)

    DTIC Science & Technology

    2006-07-01

    YSZ), gold, diamond like carbon ( DLC ) and MoS2 were synthesized using magnetron assisted pulsed laser deposition (MSPLD). The coatings were...synthesized in four-component and three-component combinations that included YSZ/Au/ DLC /MoS2, YSZ/Au/MoS2, and YSZ/Au/ DLC . A range of coating compositions... DLC /MoS2 coatings, the optimal compositions for friction adaptation between dry nitrogen and humid air included relatively high concentrations of the

  6. Electron cyclotron resonance deposition of diamond-like films

    NASA Technical Reports Server (NTRS)

    Shing, Y. H.; Pool, F. S.

    1990-01-01

    Electron cyclotron resonance (ECR) microwave plasma CVD has been developed at low pressures (0.0001 - 0.01 torr) and at ambient and high substrate temperatures (up to 750 C), to achieve large-area (greater than 4 in. diameter) depositions of diamondlike amorphous carbon (a - C:H) films. The application of a RF bias to the substrate stage, which induces a negative self-bias voltage, is found to play a critical role in determining carbon bonding configurations and in modifying the film morphology. There are two distinct types of ECR-deposited diamondlike films. One type of diamondlike film exhibits a Raman spectrum consisting of broad and overlapping, graphitic D (1360/cm, line width = 280/cm) and G (1590/cm, line width 140/cm) lines, and the other type has a broad Raman peak centered at appoximately 1500/cm. Examination of plasma species by optical emission spectroscopy shows no correlation between the CH-asterisk emission intensity and the deposition rate of diamondklike films.

  7. Superconductive niobium films coating carbon nanotube fibers

    NASA Astrophysics Data System (ADS)

    Salvato, M.; Lucci, M.; Ottaviani, I.; Cirillo, M.; Behabtu, N.; Young, C. C.; Pasquali, M.; Vecchione, A.; Fittipaldi, R.; Corato, V.

    2014-11-01

    Superconducting niobium (Nb) has been successfully obtained by sputter deposition on carbon nanotube fibers. The transport properties of the niobium coating the fibers are compared to those of niobium thin films deposited on oxidized Si substrates during the same deposition run. For niobium films with thicknesses above 300 nm, the niobium coating the fibers and the thin films show similar normal state and superconducting properties with critical current density, measured at T = 4.2 K, of the order of 105 A cm-2. Thinner niobium layers coating the fibers also show the onset of the superconducting transition in the resistivity versus temperature dependence, but zero resistance is not observed down to T = 1 K. We evidence by scanning electron microscopy (SEM) and current-voltage measurements that the granular structure of the samples is the main reason for the lack of true global superconductivity for thicknesses below 300 nm.

  8. Solid nanocrystalline fullerite-containing carbon coatings

    NASA Astrophysics Data System (ADS)

    Oskomov, K. V.; Sochugov, N. S.; Solov'ev, A. A.; Rabotkin, S. V.

    2009-10-01

    Solid carbon coatings with a high content of nanocrystalline fullerite have been obtained using unbalanced magnetron sputtering of graphite under conditions of pulsed high-voltage ion bombardment of the film growing on a substrate. It is established that samples possessing the maximum hardness (18.8 GPa) are characterized by maximum values of the volume fraction of fullerite in the coating (50%), coherent scattering domain size (53 nm), degree of preferred grain orientation (85%), relative deformation of the lattice (1.02%), and internal compressive stresses (2.91 GPa). The observed behavior is consistent with the mechanism of strengthening that accounts for the phenomenon of superhardness in nanocrystalline and nanocomposite materials. This assumption is confirmed by the results of investigation of the morphology of growing coatings.

  9. Binder for Carbon-Fiber Coating

    NASA Technical Reports Server (NTRS)

    Dowler, W. L.; Ramohalli, K. N.; Yen, S. P. S.; Mueller, W. A.; Harper, J.

    1984-01-01

    Insoluble, even coating formed by soaking in polyacrylic acid. Carbon fiber material prepared by soaking in solution of 20 percent polyacrylic acid in water. Material blotted and dried at 120 degrees C for at least 2 hours. Dried material reacted with boiling aqueous solution of calcium acetate. Treated material removed from boiling solution, blotted, dried at 120 degrees C, washed with distilled water, and dried again.

  10. Thin Coatings of Polymeric Carbon and Carbon Nanotubes for Corrosion Protection

    DTIC Science & Technology

    2009-02-01

    Carbon Nanotube Functionalization /Doping Polyvinylpyrrolidone (PVP) A) p-Doping C) Polymer Wrapping Model B) n-Doping Polyethyleneimine ( PEI ) SWCNT Paint...fluorine-containing) groups functions as the barrier layer Multilayer Smart Carbon Nanotube Coating Insoluble polymer layer top coating -PMMA Substrate...Thin Coatings of Polymeric Carbon and Carbon Nanotubes for Corrosion Protection Zafar Iqbal Department of Chemistry and Environmental Science New

  11. Oxidation of Carbon/Carbon through Coating Cracks

    NASA Technical Reports Server (NTRS)

    Jacobson, N. S.; Roth, d. J.; Rauser, R. W.; Cawley, J. D.; Curry, D. M.

    2008-01-01

    Reinforced carbon/carbon (RCC) is used to protect the wing leading edge and nose cap of the Space Shuttle Orbiter on re-entry. It is composed of a lay-up of carbon/carbon fabric protected by a SiC conversion coating. Due to the thermal expansion mismatch of the carbon/carbon and the SiC, the SiC cracks on cool-down from the processing temperature. The cracks act as pathways for oxidation of the carbon/carbon. A model for the diffusion controlled oxidation of carbon/carbon through machined slots and cracks is developed and compared to laboratory experiments. A symmetric cylindrical oxidation cavity develops under the slots, confirming diffusion control. Comparison of cross sectional dimensions as a function of oxidation time shows good agreement with the model. A second set of oxidation experiments was done with samples with only the natural craze cracks, using weight loss as an index of oxidation. The agreement of these rates with the model is quite reasonab

  12. Carbon-Coated Silica and Silica-Coated Carbon for Elastomer Reinforcement

    NASA Astrophysics Data System (ADS)

    Kohls, D. J.; Beaucage, G.; Pratsinis, S. E.; Kammler, H.

    2000-03-01

    Recently several silica producers have introduced dual-phase grades of silica/carbon powders intended for use in elastomer reinforcement. These mass-produced, nano-structured materials have carbon content in excess of 75carbon aggregates, the intent being to enhance the strength of filler-filler networking in a nano-composite. We have recently developed pyrolytic, nano-scale silica aggregates with interfacial carbon (typically less than 3the aim of enhancing elastomer-filler interaction in green tires. Our carbon-coated silicas display improved processability in typical tire compounds and enhanced dynamic mechanical performance. We also have developed facilities to produce organically functionalized silicas using a novel, room-temperature, aerosol, chemical reactor (ASG reactor). This talk will present our results on dynamic mechanical properties of elastomer compounds with our carbon-coated silica; commercial dual-phase, silica-coated carbon; ASG-organically-modified silicas; conventional carbon black; conventional precipated and fumed silica; as well as blends of the conventional materials. The mass-fractal structure as determined by SAXS and SALS, as well as gas and DBP absorption measurements and microscopy will be presented.

  13. a Simple Method of Applying Carbon Foam Coating for Carbon/carbon Composites to Modulate Cell Compatibility

    NASA Astrophysics Data System (ADS)

    Zhang, Leilei; Li, Hejun; Lu, Jinhua; Wang, Bin; Zhao, Xueni; Cao, Sheng; He, Zibo; Zeng, Xierong

    2013-01-01

    A simple slurry method was used to prepare carbon foam coatings on biomedical carbon/carbon composites to modulate the cell compatibility. The surface morphology and microstructure of the coatings were characterized and the effect of applying carbon foam coatings on cell morphology and cell proliferation was investigated. The results showed that the carbon foam coatings, consisting of carbon microspheres, resin carbon matrices and pores, covered the carbon/carbon composites entirely and uniformly with amorphous structures. There were large numbers of pores with a size ranging from submicron to tens of micrometers being found for the coatings. The cell culture experiments exhibited that both the cell spreading and the cell proliferation were improved after the preparation of the carbon foam coatings. It could be demonstrated that applying carbon foam coatings by a simple slurry method was an effective way to improve the cell compatibility of carbon/carbon composites.

  14. Carbon coated textiles for flexible energy storage

    SciTech Connect

    Jost, Kristy; Perez, Carlos O; Mcdonough, John; Presser, Volker; Heon, Min; Dion, Genevieve; Gogotsi, Yury

    2011-01-01

    This paper describes a flexible and lightweight fabric supercapacitor electrode as a possible energy source in smart garments. We examined the electrochemical behavior of porous carbon materials impregnated into woven cotton and polyester fabrics using a traditional printmaking technique (screen printing). The porous structure of such fabrics makes them attractive for supercapacitor applications that need porous films for ion transfer between electrodes. We used cyclic voltammetry, galvanostatic cycling and electrochemical impedance spectroscopy to study the capacitive behaviour of carbon materials using nontoxic aqueous electrolytes including sodium sulfate and lithium sulfate. Electrodes coated with activated carbon (YP17) and tested at 0.25 A$g1 achieved a high gravimetric and areal capacitance, an average of 85 F$g1 on cotton lawn and polyester microfiber, both corresponding to 0.43 F$cm2.

  15. Carbon coated textiles for flexible energy storage

    SciTech Connect

    Jost, Kristy; Perez, Carlos R.; McDonough, John K.; Presser, Volker; Heon, Min; Dion, Genevieve; Gogotsi, Yury

    2011-10-20

    This paper describes a flexible and lightweight fabric supercapacitor electrode as a possible energy source in smart garments. We examined the electrochemical behavior of porous carbon materials impregnated into woven cotton and polyester fabrics using a traditional printmaking technique (screen printing). The porous structure of such fabrics makes them attractive for supercapacitor applications that need porous films for ion transfer between electrodes. We used cyclic voltammetry, galvanostatic cycling and electrochemical impedance spectroscopy to study the capacitive behaviour of carbon materials using nontoxic aqueous electrolytes including sodium sulfate and lithium sulfate. Electrodes coated with activated carbon (YP17) and tested at ~0.25 A·g⁻¹ achieved a high gravimetric and areal capacitance, an average of 85 F·g⁻¹ on cotton lawn and polyester microfiber, both corresponding to ~0.43 F·cm⁻².

  16. Diamond Coatings

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Advances in materials technology have demonstrated that it is possible to get the advantages of diamond in a number of applications without the cost penalty, by coating and chemically bonding an inexpensive substrate with a thin film of diamond-like carbon (DLC). Diamond films offer tremendous technical and economic potential in such advances as chemically inert protective coatings; machine tools and parts capable of resisting wear 10 times longer; ball bearings and metal cutting tools; a broad variety of optical instruments and systems; and consumer products. Among the American companies engaged in DLC commercialization is Diamonex, Inc., a diamond coating spinoff of Air Products and Chemicals, Inc. Along with its own proprietary technology for both polycrystalline diamond and DLC coatings, Diamonex is using, under an exclusive license, NASA technology for depositing DLC on a substrate. Diamonex is developing, and offering commercially, under the trade name Diamond Aegis, a line of polycrystalline diamond-coated products that can be custom tailored for optical, electronic and engineering applications. Diamonex's initial focus is on optical products and the first commercial product is expected in late 1990. Other target applications include electronic heat sink substrates, x-ray lithography masks, metal cutting tools and bearings.

  17. Deformation Response of Conformally Coated Carbon Nanotube Forests

    DTIC Science & Technology

    2013-11-05

    SUPPLEMENTARY NOTES 14. ABSTRACT The deformation mechanism and mechanical properties of carbon nanotube (CNT) forests conformally coated with alumina...of conformally coated carbon nanotube forests Parisa Pour Shahid Saeed Abadi1, Matthew R Maschmann2,3, Jeffery W Baur2, Samuel Graham1,4 and Baratunde...stacks.iop.org/Nano/24/475707 Abstract The deformation mechanism and mechanical properties of carbon nanotube (CNT) forests conformally coated with alumina using

  18. Carbon nanotube and graphene nanoribbon-coated conductive Kevlar fibers.

    PubMed

    Xiang, Changsheng; Lu, Wei; Zhu, Yu; Sun, Zhengzong; Yan, Zheng; Hwang, Chi-Chau; Tour, James M

    2012-01-01

    Conductive carbon material-coated Kevlar fibers were fabricated through layer-by-layer spray coating. Polyurethane was used as the interlayer between the Kevlar fiber and carbon materials to bind the carbon materials to the Kevlar fiber. Strongly adhering single-walled carbon nanotube coatings yielded a durable conductivity of 65 S/cm without significant mechanical degradation. In addition, the properties remained stable after bending or water washing cycles. The coated fibers were analyzed using scanning electron microcopy and a knot test. The as-produced fiber had a knot efficiency of 23%, which is more than four times higher than that of carbon fibers. The spray-coating of graphene nanoribbons onto Kevlar fibers was also investigated. These flexible coated-Kevlar fibers have the potential to be used for conductive wires in wearable electronics and battery-heated armors.

  19. Elastic properties, sp³ fraction, and Raman scattering in low and high pressure synthesized diamond-like boron rich carbides

    SciTech Connect

    Zinin, Pavel V.; Burgess, Katherine; Jia, Ruth; Sharma, Shiv; Ming, Li-Chung; Liu, Yongsheng; Ciston, Jim; Hong, Shiming

    2014-10-07

    Dense BC{sub x} phases with high boron concentration are predicted to be metastable, superhard, and conductors or superconductors depending on boron concentration. However, up to this point, diamond-like boron rich carbides BC{sub x} (dl-BC{sub x}) phases have been thought obtainable only through high pressure and high temperature treatment, necessitating small specimen volume. Here, we use electron energy loss spectroscopy combined with transmission electron microscopy, Raman spectroscopy, surface Brillouin scattering, laser ultrasonics (LU) technique, and analysis of elastic properties to demonstrate that low pressure synthesis (chemical vapor deposition) of BC{sub x} phases may also lead to the creation of diamond-like boron rich carbides. The elastic properties of the dl-BC{sub x} phases depend on the carbon sp²versus sp³ content, which decreases with increasing boron concentration, while the boron bonds determine the shape of the Raman spectra of the dl-BC{sub x} after high pressure-high temperature treatment. Using the estimation of the density value based on the sp³ fraction, the shear modulus μ of dl-BC₄, containing 10% carbon atoms with sp³ bonds, and dl-B₃C₂, containing 38% carbon atoms with sp³ bonds, were found to be μ = 19.3 GPa and μ = 170 GPa, respectively. The presented experimental data also imply that boron atoms lead to a creation of sp³ bonds during the deposition processes.

  20. Thermoplastic coated carbon fibers for textile preforms

    NASA Technical Reports Server (NTRS)

    Allen, L. E.; Edie, D. D.; Lickfield, G. C.; Mccollum, J. R.

    1988-01-01

    A continuous process for producing prepreg from carbon fiber and thermoplastic matrix is described. After the tow has been spread using a pneumatic device, the process utilizes a fluidized bed to apply thermoplastic powder to the bundle. Finally, direct electrical heating of the coated fiber tow melts the polymer on the individual fibers, creating a uniform and extremely flexible prepreg. The efficiency of the process was evaluated during initial trials in which a thermoplastic polyimide, LaRC-TPI, was applied to T-300, 3K (3000 filament) carbon fiber tow. The physical properties of unidirectional composite specimens fabricated from this prepreg were measured, and the matrix uniformity and void content of the samples was determined. The results of these evaluations are detailed and discussed.

  1. Diamondlike carbon protective coatings for optical windows

    NASA Technical Reports Server (NTRS)

    Swec, Diane M.; Mirtich, Michael J.

    1989-01-01

    Diamondlike carbon (DLC) films were deposited on infrared transmitting optical windows and were evaluated as protective coatings for these windows exposed to particle and rain erosion. The DLC films were deposited on zinc selenide (ZnSe) and zinc sulfide (ZnS) by three different ion beam methods: (1) sputter deposition from a carbon target using an 8-cm argon ion source; (2) direct deposition by a 30-cm hollow cathode ion source with hydrocarbon gas in argon; and (3) dual beam direct deposition by the 30-cm hollow cathode ion source and an 8-cm argon ion source. In an attempt to improve the adherence of the DLC films on ZnSc and ZnS, ion beam cleaning, ion implantation with helium and neon ions, or sputter deposition of a thin, ion beam intermediate coating was employed prior to deposition of the DLC film. The protection that the DLC films afforded the windows from particle and rain erosion was evaluated, along with the hydrogen content, adherence, intrinsic stress, and infrared transmittance of the films. Because of the elevated stress levels in the ion beam sputtered DLC films and in those ion beam deposited with butane, films thicker than 0.1 micron and with good adherence on ZnS and ZnSe could not be generated. An intermediate coating of germanium successfully allowed the DLC films to remain adherent to the optical windows and caused only negligible reduction in the specular transmittance of the ZnS and ZnSe at 10 microns.

  2. Capacitive Measurement Of Coating Thickness On Carbon Fibers

    NASA Technical Reports Server (NTRS)

    Eftekhari, Abe; Chapman, John J.

    1994-01-01

    Technique for gauging coating thickness during prepreg processing of carbon fibers developed. Technique based on measurement of capacitance of cylindrical condenser through which bundle of prepregged fibers passed axially. Empirical results indicate capacitance linearly related to thickness of polymer coat on fibers in bundle. Capacitive transducer used successfully to measure thickness of polymer coats on several test bundles of fibers under static conditions.

  3. Carbon based prosthetic devices

    SciTech Connect

    Devlin, D.J.; Carroll, D.W.; Barbero, R.S.; Archuleta, T.; Klawitter, J.J.; Ogilvie, W.; Strzepa, P.; Cook, S.D.

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project objective was to evaluate the use of carbon/carbon-fiber-reinforced composites for use in endoprosthetic devices. The application of these materials for the metacarpophalangeal (MP) joints of the hand was investigated. Issues concerning mechanical properties, bone fixation, biocompatibility, and wear are discussed. A system consisting of fiber reinforced materials with a pyrolytic carbon matrix and diamond-like, carbon-coated wear surfaces was developed. Processes were developed for the chemical vapor infiltration (CVI) of pyrolytic carbon into porous fiber preforms with the ability to tailor the outer porosity of the device to provide a surface for bone in-growth. A method for coating diamond-like carbon (DLC) on the articulating surface by plasma-assisted chemical vapor deposition (CVD) was developed. Preliminary results on mechanical properties of the composite system are discussed and initial biocompatibility studies were performed.

  4. Mo doped DLC nanocomposite coatings with improved mechanical and blood compatibility properties

    NASA Astrophysics Data System (ADS)

    Tang, X. S.; Wang, H. J.; Feng, L.; Shao, L. X.; Zou, C. W.

    2014-08-01

    Mo (molybdenum) doped diamond like carbon (Mo-DLC) coatings with improved mechanical and blood compatibility properties were deposited by closed field unbalanced magnetron sputtering. The undoped and Mo-doped DLC coatings were analyzed by various characterization techniques such as Raman spectra, Atomic force microscopy, and temperature-dependent frictional wear testing. The results showed that the Mo-DLC coating with low Mo concentration was a effective protective coating with reduced residual stress and increased cohesive strength, and kept good wear resistance at the ambient temperature of 500 °C. The blood compatibility of Mo-DLC coatings was investigated by platelet adhesion. The results showed that the amount of thrombus on the Mo-DLC nanocomposite coatings was much less than that of thrombus on pyrolytic carbon films. The Mo-DLC nanocomposite coatings would be a new kind of promising materials applied to artificial heart valve and endovascula stent.

  5. Laser-induced deposition of diamond-like amorphous films and their properties

    NASA Astrophysics Data System (ADS)

    Tarasenko, S. N.

    1990-10-01

    A method is proposed for producing diamond-like amorphous films using a pulsed TEA CO2 laser. The quality of the films is largely determined by the distance from the target to the substrate, energy composition of the plasma particles, and overlap of the plasma near the target by the plasma beam incident at 45 degrees and providing the additional heating of the plasma jet. The density of the films and their optical characteristics affect their stability to irradiation; the films have a stability threshold of 10 to the 7th W/sq cm for a laser wavelength of 1.06 micron.

  6. On the origin of a band gap in compounds of diamond-like structures.

    PubMed

    Köhler, Jürgen; Deng, Shuiquan; Lee, Changhoon; Whangbo, Myung-Hwan

    2007-03-19

    Electronic structure calculations were performed to examine the origin of a band gap present in most 18-electron half-Heusler compounds and its absence in NaTl. In these compounds of diamond-like structures, the presence or absence of a band gap is controlled by the sigma antibonding between the valence s orbitals, and the bonding characteristics of the late-main-group elements depend on the extent of their ns/np hybridization. Implications of these observations on the formal oxidation state and the covalent bonding of the transition-metal atoms in 18-electron half-Heusler and related compounds were discussed.

  7. High surface area silicon carbide-coated carbon aerogel

    DOEpatents

    Worsley, Marcus A; Kuntz, Joshua D; Baumann, Theodore F; Satcher, Jr, Joe H

    2014-01-14

    A metal oxide-carbon composite includes a carbon aerogel with an oxide overcoat. The metal oxide-carbon composite is made by providing a carbon aerogel, immersing the carbon aerogel in a metal oxide sol under a vacuum, raising the carbon aerogel with the metal oxide sol to atmospheric pressure, curing the carbon aerogel with the metal oxide sol at room temperature, and drying the carbon aerogel with the metal oxide sol to produce the metal oxide-carbon composite. The step of providing a carbon aerogel can provide an activated carbon aerogel or provide a carbon aerogel with carbon nanotubes that make the carbon aerogel mechanically robust. Carbon aerogels can be coated with sol-gel silica and the silica can be converted to silicone carbide, improved the thermal stability of the carbon aerogel.

  8. DLC coating of textile blood vessels using PLD

    NASA Astrophysics Data System (ADS)

    Kocourek, Tomas; Jelinek, Miroslav; Vorlíček, Vladimír; Zemek, Josef; Janča, Tomáš; Žížková, Věra; Podlaha, Jiří; Popov, Cyril

    2008-11-01

    Textile blood vessels with a length of 30 cm were coated with amorphous diamond-like carbon (DLC) layers with thicknesses up to 200 nm. The layers were created by pulsed laser deposition in vacuum or argon ambient. The percentage of sp3 carbon was evaluated using X-ray photoelectron spectroscopy, X-ray excited Auger electron spectroscopy and Raman spectroscopy. Depending on the deposition conditions the sp3 content varied from ˜40% to 60%. The adhesion of the DLC layers to the textile vessels was checked. The preliminary biocompatibility results from in vivo tests with sheep are also given.

  9. Polymer coatings to functionalize carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Abou Rich, S.; Yedji, M.; Amadou, J.; Terwagne, G.; Felten, A.; Avril, L.; Pireaux, J.-J.

    2012-03-01

    Multi-walled carbon nanotubes (MWCNTs) were modified by plasma polymerization with methyl methacrylate (MMA) and allylamine (AA) as monomers. Conditions of the MMA and AA plasma polymerization processes in a specially designed reactor and the plasma-polymerized MMA and AA coatings were studied. The chemical composition of the surface was analyzed by X-ray Photoelectron Spectroscopy (XPS); the polymer deposited on the CNTs surface was visualized by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), while Fourier Transform Infrared spectroscopy (FTIR) allowed checking for the chemical structure of deposited plasma polymers (PP). In this work, we show that plasma functionalization creates C=O and C-O-C functional groups, or C-NH2 at the MWCNT surface, as a result of polymer deposited during the MMA or AA plasma treatments, respectively.

  10. Lubrication by Diamond and Diamondlike Carbon Coatings

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1997-01-01

    Regardless of environment (ultrahigh vacuum, humid air, dry nitrogen, or water), ion-beam-deposited diamondlike carbon (DLC) and nitrogen-ion-implanted, chemical-vapor-deposited (CVD) diamond films had low steady-state coefficients of friction (less than 0.1) and low wear rates (less than or equal to 10(exp -6)cu mm/N(dot)m). These films can be used as effective wear-resistant, self-lubricating coatings regardless of environment. On the other hand, as-deposited, fine-grain CVD diamond films; polished, coarse-grain CVD diamond films; and polished and then fluorinated, coarse-grain CVD diamond films can be used as effective wear-resistant, self-lubricating coatings in humid air, in dry nitrogen, and in water, but they had a high coefficient of friction and a high wear rate in ultrahigh vacuum. The polished, coarse-grain CVD diamond film revealed an extremely low wear rate, far less than 10(exp 10) cu mm/N(dot)m, in water.

  11. Optimization and characterization of adhesion properties of DLC coatings on different substrates

    NASA Astrophysics Data System (ADS)

    Waseem, B.; Alam, S.; Irfan, M.; Shahid, M.; Soomro, B. D.; Hashim, S.; Iqbal, R.

    2014-06-01

    The Diamond Like Carbon coatings (DLC) are gaining prime importance in the field of surface engineering especially cutting tools technology. The self lubricating property of these coatings makes them unique among other coatings like TiN, TiAlN, CrN etc. Unlike other coatings, DLC coatings give better surface finish and their self lubrication reduces the wear of a part to large extent. In present work, different substrates were selected to study the wear and adhesion behavior of DLC coatings. The coating was produced by physical Vapor Deposition (PVD) technique and the adhesive properties of DLC coatings were analyzed under ambient conditions using nano Scratch testing. Scanning electron microscope (SEM) was used to observe the scratches and their mechanisms.

  12. A study of cooling time reduction of interferometric cryogenic gravitational wave detectors using a high-emissivity coating

    SciTech Connect

    Sakakibara, Y.; Yamamoto, K.; Chen, D.; Tokoku, C.; Uchiyama, T.; Ohashi, M.; Kuroda, K.; Kimura, N.; Suzuki, T.; Koike, S.

    2014-01-29

    In interferometric cryogenic gravitational wave detectors, there are plans to cool mirrors and their suspension systems (payloads) in order to reduce thermal noise, that is, one of the fundamental noise sources. Because of the large payload masses (several hundred kg in total) and their thermal isolation, a cooling time of several months is required. Our calculation shows that a high-emissivity coating (e.g. a diamond-like carbon (DLC) coating) can reduce the cooling time effectively by enhancing radiation heat transfer. Here, we have experimentally verified the effect of the DLC coating on the reduction of the cooling time.

  13. The oxidation behavior of carbon-carbon composites and their coatings

    SciTech Connect

    Schaeffer, J.C.

    1989-01-01

    The oxidation of carbon-carbon composites and coatings in oxygen at temperatures between 300 and 1400 C was investigated. State-of-the-art systems were characterized prior to the oxidation studies using optical and scanning electron microscopy. It was determined that uncoated carbon-carbon composites cannot be used at temperatures above about 400 C for extended periods of time because of oxidation. Oxidation does occur at temperatures below 400 C but at very low rates. Boron was found to be an ineffective inhibitor for carbon-carbon oxidation. Coatings were useful in protecting carbon-carbon composites from oxidation under isothermal test conditions but these coatings failed under cyclic conditions. The factors leading to the failure of coatings on carbon-carbon composites are described.

  14. Composite protective coating for carbon-carbon substrates

    SciTech Connect

    Patten, J.W.; Forcht, B.A.; Moss, R.W.

    1985-02-19

    Composite protective coatings for protecting carbonaceous substrates from degrading in oxygen containing environments are provided. The composite protective coatings include a first coating layer applied to the surface of the substrate. The first coating layer is a silicon carbide type coating. The second coating layer is applied to the surface of a first coating layer and is a sputter deposited phase stabilized zirconium oxide having a columnar microstructure. Carbonaceous substrates having the composite protective coatings are able to withstand temperatures of about 4100/sup 0/ F. in oxygen containing environments.

  15. Superhydrophobic activated carbon-coated sponges for separation and absorption.

    PubMed

    Sun, Hanxue; Li, An; Zhu, Zhaoqi; Liang, Weidong; Zhao, Xinhong; La, Peiqing; Deng, Weiqiao

    2013-06-01

    Highly porous activated carbon with a large surface area and pore volume was synthesized by KOH activation using commercially available activated carbon as a precursor. By modification with polydimethylsiloxane (PDMS), highly porous activated carbon showed superhydrophobicity with a water contact angle of 163.6°. The changes in wettability of PDMS- treated highly porous activated carbon were attributed to the deposition of a low-surface-energy silicon coating onto activated carbon (confirmed by X-ray photoelectron spectroscopy), which had microporous characteristics (confirmed by XRD, SEM, and TEM analyses). Using an easy dip-coating method, superhydrophobic activated carbon-coated sponges were also fabricated; those exhibited excellent absorption selectivity for the removal of a wide range of organics and oils from water, and also recyclability, thus showing great potential as efficient absorbents for the large-scale removal of organic contaminants or oil spills from water.

  16. Method for applying pyrolytic carbon coatings to small particles

    DOEpatents

    Beatty, Ronald L.; Kiplinger, Dale V.; Chilcoat, Bill R.

    1977-01-01

    A method for coating small diameter, low density particles with pyrolytic carbon is provided by fluidizing a bed of particles wherein at least 50 per cent of the particles have a density and diameter of at least two times the remainder of the particles and thereafter recovering the small diameter and coated particles.

  17. Tungsten disulphide coated multi-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Whitby, R. L. D.; Hsu, W. K.; Boothroyd, C. B.; Kroto, H. W.; Walton, D. R. M.

    2002-06-01

    Multi-walled carbon nanotubes (MWCNs), coated with ordered WS 2 mono- or multi-layers, are generated by pyrolysing H 2S/N 2 over MWCNs thinly coated with WO 3. High-resolution transmission electron microscopy (HRTEM) reveals the presence of hexagonal WS 2 arrays in the tube surface, consistent with the WS 2 simulated structure.

  18. On axisymmetric/diamond-like mode transitions in axially compressed core-shell cylinders

    NASA Astrophysics Data System (ADS)

    Xu, Fan; Potier-Ferry, Michel

    2016-09-01

    Recent interests in curvature- and stress-induced pattern formation and pattern selection motivate the present study. Surface morphological wrinkling of a cylindrical shell supported by a soft core subjected to axial compression is investigated based on a nonlinear 3D finite element model. The post-buckling behavior of core-shell cylinders beyond the first bifurcation often leads to complicated responses with surface mode transitions. The proposed finite element framework allows predicting and tracing these bifurcation portraits from a quantitative standpoint. The occurrence and evolution of 3D instability modes including sinusoidally deformed axisymmetric patterns and non-axisymmetric diamond-like modes will be highlighted according to critical dimensionless parameters. Besides, the phase diagram obtained from dimensional analyses and numerical results could be used to guide the design of core-shell cylindrical systems to achieve the desired instability patterns.

  19. On the nature of interface of carbon nanotube coated carbon fibers with different polymers

    NASA Astrophysics Data System (ADS)

    Singh Bedi, Harpreet; Padhee, Srikant S.; Agnihotri, Prabhat K.

    2016-07-01

    Experimental investigations are carried out to analyse the wetting behaviour of carbon nanotube (CNT) coated carbon fiber to determine their suitability to process carbon nanotube coated carbon fiber/polymer multiscale composites for structural applications. To overcome the problem of agglomeration, CNTs are grown directly on the surface of carbon fibers as well as fabric using thermal chemical vapour deposition (CVD) technique. The term multiscale is used because different reinforcement mechanisms operate at the scale of long fibers and CNTs which are of few micrometers in length. The load carrying capacity of these multiscale composites critically depends on the efficiency and extent of load transfer from low strength matrix to high strength fiber which in turn depends on the interfacial strength between CNT coated carbon fiber and polymer matrix. A systematic analysis of wetting behaviour of CNT coated carbon fiber with epoxy and polyester matrix is carried out in this study. It is shown that CNT coated carbon fibers as well as fabric show better wettability with epoxy matrix as compared to polyester matrix. This results in stronger interface of CNT coated carbon fiber with epoxy as compared to polyester in multiscale composite system. A similar observation is made in nanoindentation testing of single fiber multiscale composites processed with epoxy and polyester matrix. In addition, it is observed that wettability, interfacial strength and average properties of CNT coated carbon fiber/polymer composites are a function of CNT density on the surface of carbon fibers.

  20. FTIR Spectroscopy for Carbon Family Study.

    PubMed

    Ţucureanu, Vasilica; Matei, Alina; Avram, Andrei Marius

    2016-11-01

    Fourier transform Infrared (FTIR) spectroscopy is a versatile technique for the characterization of materials belonging to the carbon family. Based on the interaction of the IR radiation with matter this technique may be used for the identification and characterization of chemical structures. Most important features of this method are: non-destructive, real-time measurement and relatively easy to use. Carbon basis for all living systems has found numerous industrial applications from carbon coatings (i.e. amorphous and nanocrystalline carbon films: diamond-like carbon (DLC) films) to nanostructured materials (fullerenes, nanotubes, graphene) and carbon materials at nanoscale or carbon dots (CDots). In this paper, we present the FTIR vibrational spectroscopy for the characterization of diamond, amorphous carbon, graphite, graphene, carbon nanotubes (CNTs), fullerene and carbon quantum dots (CQDs), without claiming to cover entire field.

  1. Hard Carbon Films Deposited under Various Atmospheres

    NASA Astrophysics Data System (ADS)

    Wei, M.-K.; Chen, S.-C.; Wu, T. C.; Lee, Sanboh

    1998-03-01

    Using a carbon target ablated with an XeCl-excimer laser under various gas atmospheres at different pressures, hard carbon was deposited on silicon, iron and tungsten carbide substrates. The hardness, friction coefficient, and wear rate of the film against steel are better than pure substrate material, respectively, so that it has potential to be used as a protective coating for micromechanical elements. The influences of gas pressure, gas atmosphere, and power density of laser irradiation on the thermal stability of film were analyzed by means of Raman-spectroscope, time-of-flight method, and optical emission spectrum. It was found that the film deposited under higher pressure has less diamond-like character. The film deposited under rest gas or argon atmosphere was very unstable and looked like a little graphite-like character. The film deposited at high vacuum (10-5 mbar rest gas) was the most stable and looked like the most diamond-like character. The film deposited at higher power density was more diamond-like than that at lower power density.

  2. Carbon coating of simulated nuclear-waste material

    SciTech Connect

    Blocher, J.M. Jr.; Browning, M.F.; Kidd, R.W.

    1982-03-01

    The development of low-temperature pyrolytic carbon (LT-PyC) coatings as described in this report was initiated to reduce the release of volatile waste form components and to permit the coating of larger glass marbles that have low temperature softening points (550 to 600/sup 0/C). Fluidized bed coaters for smaller particles (<2mm) and newly developed screw-agitated coaters for larger particles (>2mm) were used. Coating temperatures were reduced from >1000/sup 0/C for conventional CVD high temperature PyC to approx. 500/sup 0/C by using a catalyst. The coating gas combination that produced the highest quality coatings was found to be Ni(CO)/sub 4/ as the catalyst, C/sub 2/H/sub 2/ as the carbon source gas, and H/sub 2/ as a diluent. Carbon deposition was found to be temperature dependent with a maximum rate observed at 530/sup 0/C. Coating rates were typically 6 to 7 ..mu..m/hour. The screw-agitated coater approach to coating large-diameter particles was demonstrated to be feasible. Clearances are important between the auger walls and coater to eliminate binding and attrition. Coatings prepared in fluidized bed coaters using similar parameters are better in quality and are deposited at two to three times the rate as in screw-agitated coaters.

  3. Formation mechanism of a silicon carbide coating for a reinforced carbon-carbon composite

    NASA Technical Reports Server (NTRS)

    Rogers, D. C.; Shuford, D. M.; Mueller, J. I.

    1975-01-01

    Results are presented for a study to determine the mechanisms involved in a high-temperature pack cementation process which provides a silicon carbide coating on a carbon-carbon composite. The process and materials used are physically and chemically analyzed. Possible reactions are evaluated using the results of these analytical data. The coating is believed to develop in two stages. The first is a liquid controlled phase process in which silicon carbide is formed due to reactions between molten silicon metal and the carbon. The second stage is a vapor transport controlled reaction in which silicon vapors react with the carbon. There is very little volume change associated with the coating process. The original thickness changes by less than 0.7%. This indicates that the coating process is one of reactive penetration. The coating thickness can be increased or decreased by varying the furnace cycle process time and/or temperature to provide a wide range of coating thicknesses.

  4. Oxidation resistant slurry coating for carbon-based materials

    NASA Technical Reports Server (NTRS)

    Smialek, J. L.; Rybicki, G. C. (Inventor)

    1985-01-01

    An oxidation resistant coating is produced on carbon-base materials, and the same processing step effects an infiltration of the substrate with silicon containing material. The process comprises making a slurry of nickel and silicon powders in a nitrocellulose lacquer, spraying onto the graphite or carbon-carbon substrate, and sintering in vacuum to form a fused coating that wets and covers the surface as well as penetrates into the pores of the substrate. Optimum wetting and infiltration occurs in the range of Ni-60 w/o Si to Ni-90 w/o Si with deposited thicknesses of 25-100 mg/sq. cm. Sintering temperatures of about 1200 C to about 1400 C are used, depending on the melting point of the specific coating composition. The sintered coating results in Ni-Si intermetallic phases and SiC, both of which are highly oxidation resistant.

  5. Multilayered Polymer Coated Carbon Nanotubes to Deliver Dasatinib

    PubMed Central

    Moore, Thomas L.; Grimes, Stuart W.; Lewis, Robert L.; Alexis, Frank

    2014-01-01

    Multilayered, multifunctional polymer coatings were grafted onto carbon nanotubes (CNT) using a one-pot, ring-opening polymerization in order to control the release kinetic and therapeutic efficacy of dasatinib. Biocompatible, biodegradable multilayered coatings composed of poly(glycolide) (PGA), and poly(lactide) (PLA) were polymerized directly onto hydroxyl-functionalized CNT surfaces. Sequential addition of monomers into the reaction vessel enabled multilayered coatings of PLA-PGA, or PGA-PLA. Poly(ethylene glycol) capped the polymer chain ends, resulting in a multifunctional amphiphilic coating. Multilayer polymer coatings on CNTs enabled control of anticancer dasatinib’s release kinetics and enhanced the in vitro therapeutic efficacy against U-87 glioblastoma compared to monolayer polymer coatings. PMID:24294824

  6. Reinforced Carbon Carbon (RCC) oxidation resistant material samples - Baseline coated, and baseline coated with tetraethyl orthosilicate (TEOS) impregnation

    NASA Technical Reports Server (NTRS)

    Gantz, E. E.

    1977-01-01

    Reinforced carbon-carbon material specimens were machined from 19 and 33 ply flat panels which were fabricated and processed in accordance with the specifications and procedures accepted for the fabrication and processing of the leading edge structural subsystem (LESS) elements for the space shuttle orbiter. The specimens were then baseline coated and tetraethyl orthosilicate impregnated, as applicable, in accordance with the procedures and requirements of the appropriate LESS production specifications. Three heater bars were ATJ graphite silicon carbide coated with the Vought 'pack cementation' coating process, and three were stackpole grade 2020 graphite silicon carbide coated with the chemical vapor deposition process utilized by Vought in coating the LESS shell development program entry heater elements. Nondestructive test results are reported.

  7. An investigation of material properties and tribological performance of magnetron sputtered thin film coatings

    NASA Astrophysics Data System (ADS)

    Singh, Harpal

    This dissertation is divided into two categories based upon lubrication functionality and its application. The categories are: Dry film lubrication and Fluid film lubrication with thin film coatings. Thin film coatings examined in this work were deposited using closed field unbalanced magnetron sputtering and RF-DC coupled magnetron sputtering systems. In Dry/Solid film lubrication, the mechanical, structural and tribological properties of two Molybdenum disulphide (MoS2) based coatings are examined and evaluated. Among the two coatings, one coating is doped with Ti (Ti-MoS2) and the other is a combination of metal, lubricant and oxide (Sb2O3/Au - MoS2). These coatings are known to provide low friction in vacuum environments. The goal of this work was to evaluate friction and wear performance of MoS2 doped coatings in unidirectional and reciprocating sliding contact under different environmental conditions. Sliding contact results showed friction and wear dependence on temperature and humidity. The formation and removal of transfer films and the recrystallization and reorientation of basal layers on the steel counterface was observed as the mechanism for low friction. Structural analysis revealed a relationship between the microstructural properties and tribological performance. It was also observed that the addition of dopants (Ti, Au, Sb 2O3) improved the mechanical properties as compared to pure MoS2 coatings. Further, the rolling contact performance of the coatings was measured on a five ball on rod tribometer and a Thrust bearing tribometer under vacuum and air environments. The rolling contact experiments indicated that life of the rolling components depend on the amount of material present between the contacts. Fluid film lubrication with thin film coatings investigates the possibilities to improve the performance and durability of tribological components when oils and thin films are synergistically coupled. In this work, the ability of a Diamond Like Carbon

  8. Functionalization, coordination, and coating of carbon nanomaterials

    NASA Astrophysics Data System (ADS)

    Hamilton, Christopher Eric

    Single-walled carbon nanotubes were covalently end-functionalized with various donor ligands in order to facilitate the coordination of metal catalyst nanoparticles. The purpose of this study was to optimize catalyst complexation to SWNT ends, allowing growth from preformed seeds (SWNT-cats). The "SWNT amplification" method is envisioned as a route to bulk single-chirality nanotube samples. Study by 31P MAS NMR was undertaken in order to characterize SWNT phosphine derivatives. The synthesis of new N-aryl dipyridylamines (dpas) and related compounds is reported. The products, chelating N-donor ligands, will be used to prepare copper complexes. Copper dpa complexes are able to discriminate between olefin isomers in simple mixtures. Similar triarylamines have been similarly prepared and characterized; these have been tested for their ability to separate SWNTs of particular diameters (or chiral angles) by selective pi-pi stacking interactions. This method is a possible route to single or few-chirality samples, which could then be subjected to SWNT amplification. A novel method for production of high-yield dispersions of single and few layer graphene is presented. o-Dichlorobenzene suspensions of graphene provide twice the yield of previous methods. Moreover, ODCB graphene dispersions form a convenient platform from which to pursue covalent derivatization of graphene in a nonpolar medium. ODCB dispersions have been used to covalently functionalize graphene with perfluoroalkyl groups by a free radical method. Initiation of radical reactions was achieved by both UV photolysis and thermal decomposition of peroxides. Perfluoroalkylated graphene is highly exfoliated and shows great promise for use in polymer composites, lubricants and coatings. Chemical bath deposition (CBD) of II-VI semiconductor materials on SWNT substrates is demonstrated. Bulk heterojunction photovoltaic devices have been prepared from these SWNT-semiconductor composites. The CBD process of depositing

  9. Carbon-coated nanoparticle superlattices for energy applications

    NASA Astrophysics Data System (ADS)

    Li, Jun; Yiliguma, Affa; Wang, Yifei; Zheng, Gengfeng

    2016-07-01

    Nanoparticle (NP) superlattices represent a unique material architecture for energy conversion and storage. Recent reports on carbon-coated NP superlattices have shown exciting electrochemical properties attributed to their rationally designed compositions and structures, fast electron transport, short diffusion length, and abundant reactive sites via enhanced coupling between close-packed NPs, which are distinctive from their isolated or disordered NP or bulk counterparts. In this minireview, we summarize the recent developments of highly-ordered and interconnected carbon-coated NP superlattices featuring high surface area, tailorable and uniform doping, high conductivity, and structure stability. We then introduce the precisely-engineered NP superlattices by tuning/studying specific aspects, including intermetallic structures, long-range ordering control, and carbon coating methods. In addition, these carbon-coated NP superlattices exhibit promising characteristics in energy-oriented applications, in particular, in the fields of lithium-ion batteries, fuel cells, and electrocatalysis. Finally, the challenges and perspectives are discussed to further explore the carbon-coated NP superlattices for optimized electrochemical performances.

  10. Performance of CVD and CVR coated carbon-carbon in high temperature hydrogen

    NASA Astrophysics Data System (ADS)

    Adams, J. W.; Barletta, R. E.; Svandrlik, J.; Vanier, P. E.

    As a part of the component development process for the particle bed reactor (PBR), it is necessary to develop coatings which will be time and temperature stable at extremely high temperatures in flowing hydrogen. These coatings must protect the underlying carbon structure from attack by the hydrogen coolant. Degradation which causes small changes in the reactor component, e.g. hole diameter in the hot frit, can have a profound effect on operation. The ability of a component to withstand repeated temperature cycles is also a coating development issue. Coatings which crack or spall under these conditions would be unacceptable. While refractory carbides appear to be the coating material of choice for carbon substrates being used in PBR components, the method of applying these coatings can have a large effect on their performance. Two deposition processes for these refractory carbides, chemical vapor deposition (CVD) and chemical vapor reaction (CVR), have been evaluated. Screening tests for these coatings consisted of testing of coated 2-D and 3-D weave carbon-carbon in flowing hot hydrogen at one atmosphere. Carbon loss from these samples was measured as a function of time. Exposure temperatures up to 3,000 K were used, and samples were exposed in a cyclical fashion cooling to room temperature between exposures. The results of these measurements are presented along with an evaluation of the relative merits of CVR and CVD coatings for this application.

  11. Hard, infrared black coating with very low outgassing

    SciTech Connect

    Kuzmenko, P J; Behne, D M; Casserly, T; Boardman, W; Upadhyaya, D; Boinapally, K; Gupta, M; Cao, Y

    2008-06-02

    Infrared astronomical instruments require absorptive coatings on internal surfaces to trap scattered and stray photons. This is typically accomplished with any one of a number of black paints. Although inexpensive and simple to apply, paint has several disadvantages. Painted surfaces can be fragile, prone to shedding particles, and difficult to clean. Most importantly, the vacuum performance is poor. Recently a plasma enhanced chemical vapor deposition (PECVD) process was developed to apply thick (30 {micro}m) diamond-like carbon (DLC) based protective coatings to the interior of oil pipelines. These DLC coatings show much promise as an infrared black for an ultra high vacuum environment. The coatings are very robust with excellent cryogenic adhesion. Their total infrared reflectivity of < 10% at normal incidence approaches that of black paints. We measured outgas rates of <10{sup -12} Torr liter/sec cm{sup 2}, comparable to bare stainless steel.

  12. Tensile Properties of Polyimide Composites Incorporating Carbon Nanotubes-Grafted and Polyimide-Coated Carbon Fibers

    NASA Astrophysics Data System (ADS)

    Naito, Kimiyoshi

    2014-09-01

    The tensile properties and fracture behavior of polyimide composite bundles incorporating carbon nanotubes-grafted (CNT-grafted) and polyimide-coated (PI-coated) high-tensile-strength polyacrylonitrile (PAN)-based (T1000GB), and high-modulus pitch-based (K13D) carbon fibers were investigated. The CNT were grown on the surface of the carbon fibers by chemical vapor deposition. The pyromellitic dianhydride/4,4'-oxydianiline PI nanolayer coating was deposited on the surface of the carbon fiber by high-temperature vapor deposition polymerization. The results clearly demonstrate that CNT grafting and PI coating were effective for improving the Weibull modulus of T1000GB PAN-based and K13D pitch-based carbon fiber bundle composites. In addition, the average tensile strength of the PI-coated T1000GB carbon fiber bundle composites was also higher than that of the as-received carbon fiber bundle composites, while the average tensile strength of the CNT-grafted T1000GB, K13D, and the PI-coated K13D carbon fiber bundle composites was similar to that of the as-received carbon fiber bundle composites.

  13. Depth profiling analysis of solar wind helium collected in diamond-like carbon film from Genesis

    DOE PAGES

    Bajo, Ken-ichi; Olinger, Chad T.; Jurewicz, Amy J.G.; ...

    2015-01-01

    The distribution of solar-wind ions in Genesis mission collectors, as determined by depth profiling analysis, constrains the physics of ion solid interactions involving the solar wind. Thus, they provide an experimental basis for revealing ancient solar activities represented by solar-wind implants in natural samples. We measured the first depth profile of ⁴He in a collector; the shallow implantation (peaking at <20 nm) required us to use sputtered neutral mass spectrometry with post-photoionization by a strong field. The solar wind He fluence calculated using depth profiling is ~8.5 x 10¹⁴ cm⁻². The shape of the solar wind ⁴He depth profile ismore » consistent with TRIM simulations using the observed ⁴He velocity distribution during the Genesis mission. It is therefore likely that all solar-wind elements heavier than H are completely intact in this Genesis collector and, consequently, the solar particle energy distributions for each element can be calculated from their depth profiles. Ancient solar activities and space weathering of solar system objects could be quantitatively reproduced by solar particle implantation profiles.« less

  14. Investigation of non-hydrogenated DLC:Si prepared by cathodic arc[Diamond-Like Carbon

    SciTech Connect

    Monteiro, Othon R.; Delplancke-Ogletree, Marie-Paule

    2002-03-18

    Non-hydrogenated DLC films (also referred as ta-C) have been extensively studied and are used for a variety of wear related applications. Alloying DLC with refractory metals and other elements have been shown to be promising techniques to overcome some of the problems associated with pure DLC, such as excessive level of intrinsic stresses and high-temperature stability. The microstructure of DLC:Me in general consists of crystalline metal carbides dispersed in a DLC matrix. In contrary, DLC:Si has an amorphous structure. We have used filtered cathodic arc to prepare DLC:Si up to 6 percent Si, and have characterized their structure and bonding using microscopy (TEM) and spectroscopy (XPS, NEXAFS). The effect of Si in changing the bonding configuration of the C network is discussed. The microstructure is then correlated to hardness and friction measured by nano-indentation and micro-wear.

  15. Uniform and large area deposition of diamond-like carbon using RF source ion beam

    SciTech Connect

    Wu, R.L.C.; Lanter, W.; Miyoshi, K.; Heidger, S.L.; Bletzinger, P.; Garscadden, A.

    1995-12-31

    The authors have designed and constructed a large area ion beam apparatus to deposit DLC films onto 1,000 cm{sup 2} surfaces with various geometries. The use of an efficient RF excited ion gun (13.56 MHz, 1 kW power, 50--3,000 eV ion energy) with a diameter of 20 cm, enables one to generate various hydrocarbon ions with high ion beam currents, varying ionic species and less maintenance. The use of a four axis (X-Y-{theta}Y-{theta}Z) substrate scanner with computer control can produce uniform DLC films on large areas and curved surfaces. The effects of RF power, ion energy, gaseous composition, and total pressure on the properties of DLC have been systematically investigated.

  16. Molten carbonate fuel cell cathode with mixed oxide coating

    DOEpatents

    Hilmi, Abdelkader; Yuh, Chao-Yi

    2013-05-07

    A molten carbonate fuel cell cathode having a cathode body and a coating of a mixed oxygen ion conductor materials. The mixed oxygen ion conductor materials are formed from ceria or doped ceria, such as gadolinium doped ceria or yttrium doped ceria. The coating is deposited on the cathode body using a sol-gel process, which utilizes as precursors organometallic compounds, organic and inorganic salts, hydroxides or alkoxides and which uses as the solvent water, organic solvent or a mixture of same.

  17. Diamond-Coated Carbon Nanotubes for Efficient Field Emission

    NASA Technical Reports Server (NTRS)

    Dimitrijevic, Stevan; Withers, James C.

    2005-01-01

    Field-emission cathodes containing arrays of carbon nanotubes coated with diamond or diamondlike carbon (DLC) are undergoing development. Multiwalled carbon nanotubes have been shown to perform well as electron field emitters. The idea underlying the present development is that by coating carbon nanotubes with wideband- gap materials like diamond or DLC, one could reduce effective work functions, thereby reducing threshold electric-field levels for field emission of electrons and, hence, improving cathode performance. To demonstrate feasibility, experimental cathodes were fabricated by (1) covering metal bases with carbon nanotubes bound to the bases by an electrically conductive binder and (2) coating the nanotubes, variously, with diamond or DLC by plasma-assisted chemical vapor deposition. In tests, the threshold electric-field levels for emission of electrons were reduced by as much as 40 percent, relative to those of uncoated- nanotube cathodes. Coating with diamond or DLC could also make field emission-cathodes operate more stably by helping to prevent evaporation of carbon from nanotubes in the event of overheating of the cathodes. Cathodes of this type are expected to be useful principally as electron sources for cathode-ray tubes and flat-panel displays.

  18. Processing and characterization of Ultrathin carbon coatings on glass

    SciTech Connect

    Lee, H.; Rajagopalan, R.; Robinson, J.; Pantano, C.G.

    2009-04-15

    Ultrathin carbon layers, on the order of 3-6 nm in thickness, were formed on glass substrates by spin coating and pyrolysis of polymer precursors. The organic precursors used were poly(furfuryl alcohol), coal tar pitch, and a photoresist. The carbon coatings were characterized by ellipsometry, optical profilometry, water contact angle, confocal Raman spectroscopy, UV-vis spectroscopy, and atomic force microscopy. We also report the transparency, hydrophobicity, friction, weathering resistance, and electrical conductivity of the carbon-coated glass. The results reveal that up to 97% transparent, ultrathin carbon films could be formed on glass substrates with a root-mean-square roughness of less than about to 0.3 nm. This carbon layer modified the otherwise hydrophilic surface of the glass to yield a water contact angle of 85{sup o}. The coatings were also found to provide a water barrier against weathering under hot and humid conditions. A 4.5-nm-thick carbon film on glass had a sheet resistance of 55.6 k {Omega} m and a conductivity of 40 S/cm.

  19. Characterization of diamond-like nanocomposite thin films grown by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Santra, T. S.; Liu, C. H.; Bhattacharyya, T. K.; Patel, P.; Barik, T. K.

    2010-06-01

    Diamond-like nanocomposite (DLN) thin films, comprising the networks of a-C:H and a-Si:O were deposited on pyrex glass or silicon substrate using gas precursors (e.g., hexamethyldisilane, hexamethyldisiloxane, hexamethyldisilazane, or their different combinations) mixed with argon gas, by plasma enhanced chemical vapor deposition technique. Surface morphology of DLN films was analyzed by atomic force microscopy. High-resolution transmission electron microscopic result shows that the films contain nanoparticles within the amorphous structure. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS) were used to determine the structural change within the DLN films. The hardness and friction coefficient of the films were measured by nanoindentation and scratch test techniques, respectively. FTIR and XPS studies show the presence of CC, CH, SiC, and SiH bonds in the a-C:H and a-Si:O networks. Using Raman spectroscopy, we also found that the hardness of the DLN films varies with the intensity ratio ID/IG. Finally, we observed that the DLN films has a better performance compared to DLC, when it comes to properties like high hardness, high modulus of elasticity, low surface roughness and low friction coefficient. These characteristics are the critical components in microelectromechanical systems (MEMS) and emerging nanoelectromechanical systems (NEMS).

  20. Laser deposition of diamond-like films from liquid aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Simakin, A. V.; Shafeev, G. A.; Loubnin, E. N.

    2000-02-01

    Diamond-like films are deposited on transparent substrates upon exposure of its interface with liquid hydrocarbons (toluene C 6H 5CH 3, benzene C 6H 6, and cumene C 6H 5CH(CH 3) 2) to pulsed visible laser radiation of a copper vapor laser ( λ=510.6 nm). The X-ray Auger electron spectroscopy (XAES), Reflection High Energy Electron Diffraction (RHEED), profilometry, and ellipsometry are employed to characterize the deposited films. The sp 3 fraction in the films amounts to 60%-70% and depends on the precursor. The addition of diamond nanoparticles to the liquid precursor results in their incorporation into the film. The average film thickness on a glass substrate increases with the number of laser shots and then saturates at about 100 nm. The films show excellent adherence and have microhardness of 50-70 GPa, as measured by nanoindentor. The effect of auto-regulation of the film thickness is discussed as the result of competition between ablation and deposition of the film.

  1. Effects of UV laser micropatterning on frictional performance of diamond-like nanocomposite films

    NASA Astrophysics Data System (ADS)

    Zavedeev, Evgeny V.; Zilova, Olga S.; Shupegin, Mikhail L.; Barinov, Alexej D.; Arutyunyan, Natalia R.; Roch, Teja; Pimenov, Sergei M.

    2016-11-01

    We report on UV laser modification and micropatterning of diamond-like nanocomposite (DLN) films (a-C:H,Si:O) with nanosecond pulses and effects of laser surface microstructuring on the frictional performance of DLN films on the nano- and macroscale. A technique of direct laser interference patterning was applied to produce arrays of periodic linear microstructures on the DLN films. The UV laser irradiation was performed at low fluences corresponding to the regime of surface graphitization and incipient ablation. At the initial stage of the thin film modification, the laser-induced spallation and graphitization in the surface layers were found to strongly influence the nanoscale topography and mechanical properties of the DLN surface. Frictional properties of the laser-patterned DLN films were studied using (1) atomic force microscopy in lateral force mode and (2) a ball-on-flat tribometer under linear reciprocating sliding against a 100Cr6 steel ball. The lateral force microscopy measurements revealed that the laser-irradiated regions were characterized by increased friction forces due to microspallation effects and enhanced surface roughness, correlating with tribotests at the initial stage of sliding. During prolonged sliding in ambient air, both the original and laser-patterned DLN surfaces exhibited low-friction performance at the friction coefficient of 0.07-0.08.

  2. Applications of thin carbon coatings and films in injection molding

    NASA Astrophysics Data System (ADS)

    Cabrera, Eusebio Duarte

    In this research, the technical feasibility of two novel applications of thin carbon coatings is demonstrated. The first application consists of using thin carbon coatings on molds for molding ultra-thin plastic parts (<0.5 mm thickness) with lower pressures by promoting wall slip. The second application consists of a new approach to provide electromagnetic interference (EMI) shielding for plastic parts using in mold coated nanoparticle thin films or nanopapers to create a conductive top layer. During this research, the technical feasibility of a new approach was proven which provides injection molding of ultra-thin parts at lower pressures, without the need of fast heating/fast cooling or other expensive mold modification. An in-house developed procedure by other members of our group, was employed for coating the mold surface using chemical vapor deposition (CVD) resulting in a graphene coating with carbide bonding to the mold surface. The coating resulted in a significant decrease of surface friction and consequently easiness of flow when compared to their uncoated counterparts. Thermoplastic polymers and their composites are a very attractive alternative but are hindered by the non-conductive nature of polymers. There are two general approaches used to date to achieve EMI shielding for plastic products. One is to spray a conductive metal coating onto the plastic surface forming a layer that must maintain its shielding effectiveness (SE), and its adhesion to the plastic throughout the expected life of the product. However, metal coatings add undesirable weight and tend to corrode over time. Furthermore, scratching the coating may create shielding failure; therefore, a protective topcoat may be required. The other approach is to use polymer composites filled with conductive fillers such as carbon black (CB), carbon nanofiber (CNF), and carbon nanotube (CNT). While conductive fillers may increase the electrical conductivity of polymer composites, the loading of

  3. A novel carbon coating technique for foil bolometers.

    PubMed

    Sheikh, U A; Duval, B P; Labit, B; Nespoli, F

    2016-11-01

    Naked foil bolometers can reflect a significant fraction of incident energy and therefore cannot be used for absolute measurements. This paper outlines a novel coating approach to address this problem by blackening the surface of gold foil bolometers using physical vapour deposition. An experimental bolometer was built containing four standard gold foil bolometers, of which two were coated with 100+ nm of carbon. All bolometers were collimated and observed the same relatively high temperature, ohmically heated plasma. Preliminary results showed 13%-15% more incident power was measured by the coated bolometers and this is expected to be much higher in future TCV detached divertor experiments.

  4. Laser-surface-alloyed carbon nanotubes reinforced hydroxyapatite composite coatings

    SciTech Connect

    Chen Yao; Gan Cuihua; Zhang Tainua; Yu Gang; Bai Pucun; Kaplan, Alexander

    2005-06-20

    Carbon-nanotube (CNT)-reinforced hydroxyapatite composite coatings have been fabricated by laser surface alloying. Microstructural observation using high-resolution transmission electron microscopy showed that a large amount of CNTs remained with their original tubular morphology, even though some CNTs reacted with titanium element in the substrate during laser irradiation. Additionally, measurements on the elastic modulus and hardness of the composite coatings indicated that the mechanical properties were affected by the amount of CNTs in the starting precursor materials. Therefore, CNT-reinforced hydroxyapatite composite is a promising coating material for high-load-bearing metal implants.

  5. New solar selective coating based on carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Abendroth, Thomas; Leupolt, Beate; Mäder, Gerrit; Härtel, Paul; Grählert, Wulf; Althues, Holger; Kaskel, Stefan; Beyer, Eckhard

    2016-05-01

    Carbon nanotubes (CNTs) can be applied to assemble a new type of solar selective coating system for solar thermal applications. In this work the predominant absorption processes occurring by interaction with π-plasmon and Van Hove singularities (VHS) were investigated by UV-VIS-NIR spectroscopy and ellipsometry. Not only optical properties for as deposited SWCNT thin films itself, but also the potential for systematic tailoring will be presented. Besides low cost technologies required, the adjustability of optical properties, as well as their thermal stability render CNT based solar selective coatings as promising alternative to commercially available coating systems.

  6. Laser-surface-alloyed carbon nanotubes reinforced hydroxyapatite composite coatings

    NASA Astrophysics Data System (ADS)

    Chen, Yao; Gan, Cuihua; Zhang, Tainua; Yu, Gang; Bai, Pucun; Kaplan, Alexander

    2005-06-01

    Carbon-nanotube (CNT)-reinforced hydroxyapatite composite coatings have been fabricated by laser surface alloying. Microstructural observation using high-resolution transmission electron microscopy showed that a large amount of CNTs remained with their original tubular morphology, even though some CNTs reacted with titanium element in the substrate during laser irradiation. Additionally, measurements on the elastic modulus and hardness of the composite coatings indicated that the mechanical properties were affected by the amount of CNTs in the starting precursor materials. Therefore, CNT-reinforced hydroxyapatite composite is a promising coating material for high-load-bearing metal implants.

  7. A novel carbon coating technique for foil bolometers

    NASA Astrophysics Data System (ADS)

    Sheikh, U. A.; Duval, B. P.; Labit, B.; Nespoli, F.

    2016-11-01

    Naked foil bolometers can reflect a significant fraction of incident energy and therefore cannot be used for absolute measurements. This paper outlines a novel coating approach to address this problem by blackening the surface of gold foil bolometers using physical vapour deposition. An experimental bolometer was built containing four standard gold foil bolometers, of which two were coated with 100+ nm of carbon. All bolometers were collimated and observed the same relatively high temperature, ohmically heated plasma. Preliminary results showed 13%-15% more incident power was measured by the coated bolometers and this is expected to be much higher in future TCV detached divertor experiments.

  8. A new carbon structure in annealed film coatings of the carbon-lead system

    NASA Astrophysics Data System (ADS)

    Volodin, V. N.; Tuleushev, Yu. Zh.; Zhakanbaev, E. A.; Tsai, K. V.; Rofman, O. V.

    2017-01-01

    Carbon-lead solid solutions coexisting with amorphous carbon have been obtained for the first time in a film coating deposited by ion-plasma sputtering. During subsequent vacuum annealing of carbon-lead films containing more than 68.5 at % Pb, this element almost completely evaporates to leave an amorphous carbon coating on a substrate. During annealing at 1100°C, this amorphous carbon crystallizes into a new hexagonal lattice with unit cell parameters a = 0.7603 nm and c = 0.8168 nm. Characteristic X-ray diffraction data for the identification of this phase are determined.

  9. Adhesion of preceramic inorganic polymer coatings to carbon fibers

    SciTech Connect

    Chaudhry, T.M.; Drzal, L.T.; Ho, H.; Laine, R.

    1996-12-31

    To determine whether the preceramic inorganic polymer coating can provide not only the thermal oxidative protection during both processing and use in metal matrix composites or ceramic matrix composites but also the appropriate composite properties, it is desirable to know how and at what point in the thermal processing cycle the coating-carbon fiber interface undergoes changes that affect the interfacial adhesion and failure mode. Also, it is important to identify the locus of interfacial failure i.e. between fiber and coating or between coating and matrix. This work is directed at determining the interfacial changes and the locus of failure in order to optimize both the coating chemistry and the conversion process. The characteristics of the benchmark interface coating material, silicon oxycarbide, SiO{sub x}C{sub y} or black glass have been studied. SiO{sub x}C{sub y} was chosen because (1) SiO{sub x}C{sub y} is amorphous, (2) it is possible to prepare very well-defined materials, where the chemistry and the evolution of the material with time and temperature are known in detail, and (3) SiO{sub x}C{sub y} is a matrix material used in commercial composites. It has been shown that these coatings are effective in increasing the oxidation resistance of the carbon fibers themselves.

  10. Biocompatible Silver-containing a-C:H and a-C coatings: AComparative Study

    SciTech Connect

    Endrino, Jose Luis; Allen, Matthew; Escobar Galindo, Ramon; Zhang, Hanshen; Anders, Andre; Albella, Jose Maria

    2007-04-01

    Hydrogenated diamond-like-carbon (a-C:H) and hydrogen-free amorphous carbon (a-C) coatings are known to be biocompatible and have good chemical inertness. For this reason, both of these materials are strong candidates to be used as a matrix that embeds metallic elements with antimicrobial effect. In this comparative study, we have incorporated silver into diamond-like carbon (DLC) coatings by plasma based ion implantation and deposition (PBII&D) using methane (CH4) plasma and simultaneously depositing Ag from a pulsed cathodic arc source. In addition, we have grown amorphous carbon - silver composite coatings using a dual-cathode pulsed filtered cathodic-arc (FCA) source. The silver atomic content of the deposited samples was analyzed using glow discharge optical spectroscopy (GDOES). In both cases, the arc pulse frequency of the silver cathode was adjusted in order to obtain samples with approximately 5 at.% of Ag. Surface hardness of the deposited films was analyzed using the nanoindentation technique. Cell viability for both a-C:H/Ag and a-C:/Ag samples deposited on 24-well tissue culture plates has been evaluated.

  11. Hollow carbon spheres in microwaves: Bio inspired absorbing coating

    NASA Astrophysics Data System (ADS)

    Bychanok, D.; Li, S.; Sanchez-Sanchez, A.; Gorokhov, G.; Kuzhir, P.; Ogrin, F. Y.; Pasc, A.; Ballweg, T.; Mandel, K.; Szczurek, A.; Fierro, V.; Celzard, A.

    2016-01-01

    The electromagnetic response of a heterostructure based on a monolayer of hollow glassy carbon spheres packed in 2D was experimentally surveyed with respect to its response to microwaves, namely, the Ka-band (26-37 GHz) frequency range. Such an ordered monolayer of spheres mimics the well-known "moth-eye"-like coating structures, which are widely used for designing anti-reflective surfaces, and was modelled with the long-wave approximation. Based on the experimental and modelling results, we demonstrate that carbon hollow spheres may be used for building an extremely lightweight, almost perfectly absorbing, coating for Ka-band applications.

  12. Nano-coatings on carbon structures for interfacial modification

    NASA Astrophysics Data System (ADS)

    Pulikollu, Rajasekhar V.

    Surface modification of materials is a rapidly growing field as structures become smaller, more integrated and complex. It opens up the possibility of combining the optimum bulk properties of a material with optimized surface properties such as enhanced bonding, corrosion resistance, reactivity, stress transfer, and thermal, optical or electrical behavior. Therefore, surface functionalization or modification can be an enabling step in a wide variety of modern applications. In this dissertation several surface modification approaches on carbon foam and carbon nano-fibers will be discussed. These are recently developed sp2 graphitic carbon based structures that have significant potential in aerospace, automotive and thermal applications. Influence of surface modification on composite formation and properties have also been investigated. Two types of property changes have been investigated: one for enhancing the surface reactivity and another for surface inertness. Characterization techniques such as X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM), Contact Angle Measurement, Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and mechanical testing are used in this study to find out the influence of these coatings on surface composition, chemistry and morphology. Mechanical testing has been performed on composites and stand alone foam to study the influence of surface modification on physical and mechanical properties of the composite materials. The effectiveness of these coatings on metallic/graphite interface has also been investigated for metal-matrix composite related applications. Additionally, the influence of plasma coatings on nucleation and growth of nanotubes on larger carbon structures (to produce multiscale, multifunctional materials) have also been studied. It is seen that the liquid phase activation treatment introduces oxygen functional groups on the surface, but may cause severe enough degradation that

  13. Fiber optic ultrasound transducers with carbon/PDMS composite coatings

    NASA Astrophysics Data System (ADS)

    Mosse, Charles A.; Colchester, Richard J.; Bhachu, Davinder S.; Zhang, Edward Z.; Papakonstantinou, Ioannis; Desjardins, Adrien E.

    2014-03-01

    Novel ultrasound transducers were created with a composite of carbon nanotubes (CNTs) and polydimethylsiloxane (PDMS) that was dip coated onto the end faces of optical fibers. The CNTs were functionalized with oleylamine to allow for their dissolution in xylene, a solvent of PDMS. Ultrasound pulses were generated by illuminating the composite coating with pulsed laser light. At distances of 2 to 16 mm from the end faces, ultrasound pressures ranged from 0.81 to 0.07 MPa and from 0.27 to 0.03 MPa with 105 and 200 μm core fibers, respectively. Using an optical fiber hydrophone positioned adjacent to the coated 200 µm core optical fiber, ultrasound reflectance measurements were obtained from the outer surface of a sheep heart ventricle. The results of this study suggest that ultrasound transducers that comprise optical fibers with CNT-PDMS composite coatings may be suitable for miniature medical imaging probes.

  14. Deformation response of conformally coated carbon nanotube forest.

    PubMed

    Abadi, Parisa Pour Shahid Saeed; Maschmann, Matthew R; Baur, Jeffery W; Graham, Samuel; Cola, Baratunde A

    2013-11-29

    The deformation mechanism and mechanical properties of carbon nanotube (CNT) forests conformally coated with alumina using atomic layer deposition (ALD) are investigated using in situ and ex situ micro-indentation. While micro-indentation of a CNT forest coated with a thin discontinuous layer using 20 ALD cycles results in a deformation response similar to the response of uncoated CNT forests, a similar test on a CNT forest coated with a sufficiently thick and continuous layer using 100 ALD cycles causes fracture of both the alumina coatings and the core CNTs. With a 10 nm coating, 4-fold and 14-fold stiffness increases are measured using a flat punch and a Berkovich tip, respectively. Indentation testing with the Berkovich tip also reveals increased recoverability at relatively low strains. The results show that ALD coated CNT forests could be useful for applications that require higher stiffness or recoverability. Also, fracturing of the nanotubes shows that upper limits exist in the loading of conformally coated CNT forests.

  15. Lipid/Polyelectrolyte coatings to control carbon nanotubes intracellular distribution.

    PubMed

    Romero, G; Estrela-Lopis, I; Rojas, E; Llarena, I; Donath, E; Moya, S E

    2012-06-01

    Carbon Nanotubes have been functionalized with a layer of poly (sulfopropyl methacrylate) synthesized from silane initiators attached to the walls of the Carbon nanotubes. On top of the poly sulfo propyl methacrylate, lipid vesicles composed of 75% 1,2-Dioleoyl-sn-Glycero-3-Phosphocholine and 25% 1,2-Dioleoyl-sn-Glycero-3-[Phospho-L-Serine] were assembled. The surface modification of the Carbon Nanotubes and lipid assembly were followed by TEM. Confocal Raman Microscopy was used to study the uptake and localization of the surface modified Carbon Nanotubes in the HepG2 cell line. The localization of the Carbon Nanotubes in the cells was affected by the surface coating. It was found that poly (sulfopropyl methacrylate) and lipid modified Carbon Nanotubes were present in the region of the lipid bodies in the cytoplasm.

  16. Diamondlike carbon protective coatings for IR materials

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.; Nir, D.; Swec, D. M.; Banks, B. A.

    1985-01-01

    Diamondlike carbon (DLC) films have the potential to protect optical windows in applications where it is important to maintain the integrity of the specular transmittance of these films on ZnS and ZnSe infrared transmitting windows. The films must be adherent and durable such that they protect the windows from rain and particle erosion as well as chemical attack. In order to optimize the performance of these films, 0.1 micro m thick diamondlike carbon films were deposited on fused silica and silicon wafers, using three different methods of ion beam deposition. One method was sputter deposition from a carbon target using an 8 cm ion source. The merits of hydrogen addition were experimentally evaluated in conjunction with this method. The second method used a 30 cm hollow cathode ion source with hydrocarbon/Argon gases to deposit diamondlike carbon films from the primary beam at 90 to 250 eV. The third method used a dual beam system employing a hydrocarbon/Argon 30 cm ion source and an 8 cm ion source. Films were evaluated for adherence, intrinsic stress, infrared transmittance between 2.5 and 50 micro m, and protection from particle erosion. An erosion test using a sandblaster was used to give quantitative values of the protection afforded to the fused silica by the diamondlike carbon films. The fused silica surfaces protected by diamondlike carbon films were exposed to 100 micro m diameter SiO particles at 60 mi/hr (26.8/sec) in the sandblaster.

  17. Delithiation kinetics study of carbon coated and carbon free LiFePO4

    NASA Astrophysics Data System (ADS)

    Lepage, D.; Sobh, F.; Kuss, C.; Liang, G.; Schougaard, S. B.

    2014-06-01

    A chemical oxidation method was employed to measure the kinetics of lithium release from LiFePO4 during oxidation. Similar to potential step measurements, the chemical method simplifies quantification compared to the common electrochemical techniques (PITT, GITT etc.). It was found that the overall release of lithium fits one dimensional diffusion kinetics, however, it is also shown that the mechanism must be more complex as the derived activation energy led to an unusually low attack rate of ∼108 Hz. A comparison of carbon coated/carbon free LiFePO4 samples indicated that the carbon coating has only a marginal effect on the delithiation kinetics.

  18. Coating carbon nanotubes with polymer in supercritical carbon dioxide.

    PubMed

    Wang, Jiawei; Khlobystov, Andrei N; Wang, Wenxin; Howdle, Steven M; Poliakoff, Martyn

    2006-04-21

    A facile and efficient method has been developed for coating MWNTs with solvent resistant polymer in scCO2, which permits the selective deposition of high molecular weight fluorinated graft poly(methyl vinyl ether-alt-maleic anhydride) polymer onto MWNTs in scCO2 under 100-170 bar at 40 degrees C and forms quasi one-dimensional nanostructures with conducting cores and insulating surfaces.

  19. Method of producing carbon coated nano- and micron-scale particles

    DOEpatents

    Perry, W. Lee; Weigle, John C; Phillips, Jonathan

    2013-12-17

    A method of making carbon-coated nano- or micron-scale particles comprising entraining particles in an aerosol gas, providing a carbon-containing gas, providing a plasma gas, mixing the aerosol gas, the carbon-containing gas, and the plasma gas proximate a torch, bombarding the mixed gases with microwaves, and collecting resulting carbon-coated nano- or micron-scale particles.

  20. Poly(4-vinylpyridine)-coated glassy carbon flow detectors

    SciTech Connect

    Wang, J.; Golden, T.; Tuzhi, P.

    1987-03-01

    The performance of a thin-layer flow detector with a glassy carbon electrode coated with a film of protonated poly(4-vinylpyridine) is described. Substantial improvement in the selectivity of amperometric detection for liquid chromatography and flow injection systems is observed as a result of excluding cationic species from the surface. The detector response was evaluated with respect to flow rate, solute concentration, coating scheme, film-to-film reproducibility, and other variables. Despite the increase in diffusional resistance, low detection limits of ca. 0.04 and 0.10 ng of ascorbic acid and uric acid, respectively, are maintained. Protection from organic surfactants can be coupled to the charge exclusion effect by using a bilayer coating, with a cellulose acetate film atop the poly(4-vinylpyridine) layer. Applicability to urine sample is demonstrated.

  1. Development of a novel test-setup for identifying the frictional characteristics of carbon fibre reinforced polymer composites at high surface pressure

    NASA Astrophysics Data System (ADS)

    Saxena, Prateek; Schinzel, Marie; Andrich, Manuela; Modler, Niels

    2016-09-01

    Carbon fibre reinforced polymer composites are extensively used in industrial applications. They are light in weight and have excellent load bearing properties. To understand this material's behaviour when carrying loads at high pressure, a tensile-friction test device was developed that can apply a contact surface pressure between composite and counterpart of 50-300 MPa. A tribological investigation of carbon fibre reinforced epoxy composites was carried out, in which the influence of the surface morphology was investigated by using grinding and sandblasting techniques. The friction coefficient of the polymer composite was measured at 100 MPa surface pressure against uncoated and Diamond-Like Carbon coated stainless steel counterparts.

  2. Single Wall Carbon Nano Tube Films and Coatings

    NASA Astrophysics Data System (ADS)

    Sreekumar, T. V.; Kumar, Satish; Ericson, Lars M.; Smalley, Richard E.

    2002-03-01

    Purified single wall carbon nano tubes (SWNTs) produced from the high-pressure carbon monoxide (HiPCO) process have been dissolved /dispersed in oleum. These solutions /dispersions were optically homogeneous and have been used to form stand-alone SWNT films. The washed, dried, and heat-treated films are isotropic. The scanning electron micrographs of the film surface shows that the nanotube ropes (or fibrils) of about 20 nm diameters are arranged just like macroscopic fibers in a non-woven fabric. Polarized Raman spectroscopy of the SWNT film confirms the isotropic nature of these films. The films are being characterized for their thermal, mechanical as well electrical properties. Thin nano tube coatings, including optically transparent coatings, have also been made on a variety of substrates such as glass, polyethylene, polystyrene, polypropylene, silicon wafer, as well as stainless steel.

  3. Carbon--silicon coating alloys for improved irradiation stability

    DOEpatents

    Bokros, J.C.

    1973-10-01

    For ceramic nuclear fuel particles, a fission product-retaining carbon-- silicon alloy coating is described that exhibits low shrinkage after exposure to fast neutron fluences of 1.4 to 4.8 x 10/sup 21/ n/cm/sup 2/ (E = 0.18 MeV) at irradiation temperatures from 950 to 1250 deg C. Isotropic pyrolytic carbon containing from 18 to 34 wt% silicon is co-deposited from a gaseous mixiure of propane, helium, and silane at a temperature of 1350 to 1450 deg C. (Official Gazette)

  4. Carbon-Based Wear Coatings: Properties and Applications

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2003-01-01

    The technical function of numerous engineering systems - such as vehicles, machines, and instruments - depends on the processes of motion and on the surface systems. Many processes in nature and technology depend on the motion and dynamic behavior of solids, liquids, and gases. Smart surface systems are essential because of the recent technological push toward higher speeds, loads, and operating temperatures; longer life; lighter weight and smaller size (including nanotechnology); and harsh environments in mechanical, mechatronic, and biomechanical systems. If proper attention is not given to surface systems, then vehicles, machines, instruments, and other technical systems could have short lives, consume excessive energy, experience breakdowns, result in liabilities, and fail to accomplish their missions. Surface systems strongly affect our national economy and our lifestyles. At the NASA Glenn Research Center, we believe that proper attention to surface systems, especially in education, research, and application, could lead to economic savings of between 1.3 and 1.6 percent of the gross domestic product. Wear coatings and surface systems continue to experience rapid growth as new coating and surface engineering technologies are discovered, more cost-effective coating and surface engineering solutions are developed, and marketers aggressively pursue, uncover, and exploit new applications for engineered surface systems in cutting tools and wear components. Wear coatings and smart surface systems have been used widely in industrial, consumer, automotive, aerospace, and biomedical applications. This presentation expresses the author's views of and insights into smart surface systems in wear coatings. A revolution is taking place in carbon science and technology. Diamond, an allotrope of carbon, joins graphite, fullerenes, and nanotubes as its major pure carbon structures. It has a unique combination of extreme properties: hardness and abrasion resistance; adhesion

  5. Preparation and properties of in-situ growth of carbon nanotubes reinforced hydroxyapatite coating for carbon/carbon composites.

    PubMed

    Liu, Shoujie; Li, Hejun; Su, Yangyang; Guo, Qian; Zhang, Leilei

    2017-01-01

    Carbon nanotubes (CNTs) possess excellent mechanical properties for their role playing in reinforcement as imparting strength to brittle hydroxyapatite (HA) bioceramic coating. However, there are few reports relating to the in-situ grown carbon nanotubes reinforced hydroxyapatite (CNTs-HA) coating. Here we demonstrate the potential application in reinforcing biomaterials by an attempt to use in-situ grown of CNTs strengthen HA coating, using a combined method composited of injection chemical vapor deposition (ICVD) and pulsed electrodeposition. The microstructure, phases and chemical compositions of CNTs-HA coatings were characterized by various advanced methods. The scanning electron microscopy (SEM) images indicated that CNTs-HA coatings avoided the inhomogeneous dispersion of CNTs inside HA coating. The result show that the interfacial shear strength between CNTs-HA coating and the C/C composite matrix reaches to 12.86±1.43MPa. Potenitodynamic polarization and electrochemical impedance spectroscopy (EIS) studies show that the content of CNTs affects the corrosion resistance of CNTs-HA coating. Cell culturing and simulated body fluid test elicit the biocompatibility with living cells and bioactivity of CNTs-HA coatings, respectively.

  6. A Mathematical Model for Determining Carbon Coating Thickness and Its Application in Electron Probe Microanalysis.

    PubMed

    Zhang, Ruo-Xi; Yang, Shui-Yuan

    2016-12-01

    In electron probe microanalysis where materials are coated with a thin conductive carbon coat before analysis, the X-ray intensity detected from a specimen may be affected to various degrees by the thickness of the carbon coating. Differences in the carbon film thickness between specimens and standards may lead to errors in analytical results, particular for lower energy X-rays. In this study, we demonstrate that the location and the distance of the specimen relative to the carbon tip in the coating chamber can affect the thickness of the carbon film produced on the specimen surface during carbon coating. The closer the specimen is to the carbon tip contacting point, the thicker is the carbon film deposited. A mathematical model to calculate the carbon film thickness at different locations on the coater plate is established, based on the assumption that carbon atoms evaporate from the carbon tip equally in all directions during the coating process. In order to reduce the differences in the carbon coating thickness, we suggest moving the carbon rod to a higher position, moving the thinner samples to the center and thicker samples to the edge of the coater plate, and using a rotating circular coater plate during coating.

  7. Ground States of Spin-1/2 Heisenberg Antiferromagnets with Frustration on a Diamond-Like-Decorated Square Lattice

    NASA Astrophysics Data System (ADS)

    Hirose, Yuhei; Oguchi, Akihide; Fukumoto, Yoshiyuki

    2017-01-01

    We study the ground-state phase diagram of a Heisenberg model with spin S = 1/2 on a diamond-like-decorated square lattice. A diamond unit has two types of antiferromagnetic exchange interactions, and the ratio λ of the length of the diagonal bond to that of the other four edges determines the strength of frustration. It has been pointed out [J. Phys. Soc. Jpn 85, 033705 (2016)] that the so-called tetramer-dimer states, which are expected to be stabilized in an intermediate region of λc < λ < 2, are identical to the square-lattice dimer-covering states, which ignited renewed interest in high-dimensional diamond-like-decorated lattices. In order to determine the phase boundary λc, we employ the modified spin wave method to estimate the energy of the ferrimagnetic state and obtain λc = 0.974. Furthermore, our numerical diagonalization study suggests that other cluster states do not appear in the ground-state phase diagram.

  8. Polymer Coating of Carbon Nanotube Fibers for Electric Microcables

    PubMed Central

    Alvarez, Noe T.; Ochmann, Timothy; Kienzle, Nicholas; Ruff, Brad; Haase, Mark R.; Hopkins, Tracy; Pixley, Sarah; Mast, David; Schulz, Mark J.; Shanov, Vesselin

    2014-01-01

    Carbon nanotubes (CNTs) are considered the most promising candidates to replace Cu and Al in a large number of electrical, mechanical and thermal applications. Although most CNT industrial applications require macro and micro size CNT fiber assemblies, several techniques to make conducting CNT fibers, threads, yarns and ropes have been reported to this day, and improvement of their electrical and mechanical conductivity continues. Some electrical applications of these CNT conducting fibers require an insulating layer for electrical insulation and protection against mechanical tearing. Ideally, a flexible insulator such as hydrogenated nitrile butadiene rubber (HNBR) on the CNT fiber can allow fabrication of CNT coils that can be assembled into lightweight, corrosion resistant electrical motors and transformers. HNBR is a largely used commercial polymer that unlike other cable-coating polymers such as polyvinyl chloride (PVC), it provides unique continuous and uniform coating on the CNT fibers. The polymer coated/insulated CNT fibers have a 26.54 μm average diameter—which is approximately four times the diameter of a red blood cell—is produced by a simple dip-coating process. Our results confirm that HNBR in solution creates a few microns uniform insulation and mechanical protection over a CNT fiber that is used as the electrically conducting core. PMID:28344254

  9. Liquid Imbibition in Ceramic-Coated Carbon Nanotube Films.

    PubMed

    Zhao, Hangbo; Jacob, Christine; Stone, Howard A; Hart, A John

    2016-12-06

    Understanding of the liquid imbibition dynamics in nanoporous materials is important to advances in chemical separations, phase change heat transfer, electrochemical energy storage, and diagnostic assays. We study the liquid imbibition behavior in films of ceramic-coated vertically aligned carbon nanotubes (CNTs). The nanoscale porosity of the films is tuned by conformal ceramic coating via atomic layer deposition (ALD), enabling stable liquid imbibition and precise measurement of the imbibition dynamics without capillary densification of the CNTs. We show that the imbibition rate decreases as the ceramic coating thickness increases, which effectively changes the CNT-CNT spacing and therefore decreases the permeability. We derive a model, based on Darcy's law, that incorporates an expression for the permeability of nanoscale post arrays, and we show that the model fits the experimental results with high accuracy. The tailorable porosity, along with controllable surface wettability and mechanical stability of coated CNTs, suggest their suitability for application-guided engineering, and for further investigation of imbibition behavior at finer length scales.

  10. Gas Sensors Based on Coated and Doped Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Li, Jing; Meyyappan, Meyya

    2008-01-01

    Efforts are underway to develop inexpensive, low-power electronic sensors, based on single-walled carbon nanotubes (SWCNTs), for measuring part-per-million and part-per-billion of selected gases (small molecules) at room temperature. Chemically unmodified SWCNTs are mostly unresponsive to typical gases that one might wish to detect. However, the electrical resistances of SWCNTs can be made to vary with concentrations of gases of interest by coating or doping the SWCNTs with suitable materials. Accordingly, the basic idea of the present development efforts is to incorporate thus-treated SWCNTs into electronic devices that measure their electrical resistances.

  11. Deposition of DLC Film on Stainless Steel Substrates Coated by Nickel Using PECVD Method.

    PubMed

    Khalaj, Zahra; Ghoranneviss, Mahmood; Vaghri, Elnaz; Saghaleini, Amir; Diudea, Mircea V

    2012-06-01

    Research on diamond-like carbon (DLC) films has been devoted to find both optimized conditions and characteristics of the deposited films on various substrates. In the present work, we investigate the quality of the DLC films grown on stainless steel substrates using different thickness of the nickel nanoparticle layers on the surface. Nickel nanoparticles were sputtered on the stainless steel substrates at 200 °C by a DC-sputtering system to make a good adherence between DLC coating and steel substrates. Atomic Force Microscopy was used to characterize the surface roughness and distribution function of the nickel nanoparticles on the substrate surface. Diamond like carbon films were deposited on stainless steel substrates coated by nickel using pure acetylene and C2H2/H2 with 15% flow ratio by DC-Plasma Enhanced Chemical Vapor Deposition (PECVD) systems. Microstructural analysis by Raman spectroscopy showed a low intensity ratio ID/IG for DLC films by increasing the Ni layer thickness on the stainless steel substrates. Fourier Transforms Infrared spectroscopy (FTIR) evidenced the peaks attributed to C-H bending and stretching vibration modes in the range of 1300-1700 cm-1 and 2700-3100 cm-1, respectively, in good agreement with the Raman spectroscopy and confirmed the DLC growth in all samples.

  12. TiO2-coated carbon nanotubes: A redshift enhanced photocatalysis at visible light

    NASA Astrophysics Data System (ADS)

    Lu, Sheng-Yi; Tang, Chiung-Wen; Lin, Yu-Hsien; Kuo, Hsin-Fu; Lai, Yao-Cheng; Tsai, Meng-Yen; Ouyang, Hao; Hsu, Wen-Kuang

    2010-06-01

    Annealing of carbon nanotubes coated with thin and uniform TiO2 results in carbon diffusion into oxygen lattices and doping induced redshift is evident by an efficient photocatalysis at visible light. The underlying mechanism is discussed.

  13. Anisotropy measurement of pyrolytic carbon layers of coated particles

    SciTech Connect

    Vesyolkin, Ju. A. Ivanov, A. S.; Trushkina, T. V.

    2015-12-15

    Equipment at the National Research Center Kurchatov Institute intended for the anisotropy determination of pyrolytic carbon layers in coated particles (CPs) of the GT-MGR reactor is tested and calibrated. The dependence of the anisotropy coefficient on the size of the measurement region is investigated. The results of measuring the optical anisotropy factor (OPTAF) for an aluminum mirror, rutile crystal, and available CP samples with the known characteristics measured previously using ORNL equipment (United States) are presented. In addition, measurements of CP samples prepared at VNIINM are performed. A strong dependence of the data on the preparation quality of metallographic sections is found. Our investigations allow us to make the conclusion on the working capacity of the existing equipment for measuring the anisotropy of pyrolytic carbon CP coatings using the equipment at the Kurchatov Institute with the relative error of about 1%. It is shown that the elimination of the errors caused by the stochastic fluctuations in a measuring path by mathematical processing of the signal allows us to decrease the relative error of OPTAF measurements to ∼0.3%.

  14. Anisotropy measurement of pyrolytic carbon layers of coated particles

    NASA Astrophysics Data System (ADS)

    Vesyolkin, Ju. A.; Ivanov, A. S.; Trushkina, T. V.

    2015-12-01

    Equipment at the National Research Center Kurchatov Institute intended for the anisotropy determination of pyrolytic carbon layers in coated particles (CPs) of the GT-MGR reactor is tested and calibrated. The dependence of the anisotropy coefficient on the size of the measurement region is investigated. The results of measuring the optical anisotropy factor (OPTAF) for an aluminum mirror, rutile crystal, and available CP samples with the known characteristics measured previously using ORNL equipment (United States) are presented. In addition, measurements of CP samples prepared at VNIINM are performed. A strong dependence of the data on the preparation quality of metallographic sections is found. Our investigations allow us to make the conclusion on the working capacity of the existing equipment for measuring the anisotropy of pyrolytic carbon CP coatings using the equipment at the Kurchatov Institute with the relative error of about 1%. It is shown that the elimination of the errors caused by the stochastic fluctuations in a measuring path by mathematical processing of the signal allows us to decrease the relative error of OPTAF measurements to ~0.3%.

  15. Interaction of carbon nanotubes coatings with titanium substrate

    NASA Astrophysics Data System (ADS)

    Fraczek-Szczypta, Aneta; Wedel-Grzenda, Alicja; Benko, Aleksandra; Grzonka, Justyna; Mizera, Jaroslaw

    2017-02-01

    The aim of this study was to evaluate the impact of multi-walled carbon nanotubes (MWCNTs) after chemical surface functionalization on the interaction with a titanium surface. Two kinds of MWCNTs differing in terms of concentration of functional groups were deposited on the Ti surface using the electrophoretic deposition method (EPD). The study has shown the detailed analysis of the physicochemical properties of this form of carbon nanomaterial and received on their base coatings using various techniques, such as scanning electron microscopy (SEM), confocal microscopy, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The adhesion of the MWCNTs coatings to the Ti surface was determined using the shear test method, according to standard ASTM F-1044-05. These results indicated that one type of MWCNTs characterized by a higher concentration of functional groups has better adhesion to the metal surface than the second type. Analysis of the MWCNT-metal interface using Raman spectroscopy and SEM and STEM indicates the presence of phase built of MWCNT and TiO2. This phase could be a type of nanocomposite that affects the improvement of the adhesion of MWCNT to the Ti surface.

  16. Robust diamond-like Fe-Si network in the zero-strain NaxFeSiO4 cathode

    DOE PAGES

    Ye, Zhuo; Zhao, Xin; Li, Shouding; ...

    2016-07-14

    Sodium orthosilicates Na2MSiO4 (M denotes transition metals) have attracted much attention due to the possibility of exchanging two electrons per formula unit. In this work, we report a group of sodium iron orthosilicates Na2FeSiO4. Their crystal structures are characterized by a diamond-like Fe-Si network. The Fe-Si network is quite robust against the charge/discharge process, which explains the high structural stability observed in experiment. Furthermore, using the density functional theory within the GGA + U framework and X-ray diffraction studies, the crystal structures and structural stabilities during the sodium extraction/re-insertion process are systematically investigated.

  17. INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Laser deposition of amorphous diamond-like films from liquid aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Lyalin, A. A.; Simakin, Aleksandr V.; Bobyrev, V. A.; Lubnin, Evgenii N.; Shafeev, Georgii A.

    1999-04-01

    An experimental investigation was made of the deposition of amorphous diamond-like films on transparent substrates by laser irradiation of the interfaces between such substrates and liquid hydrocarbons [toluene C6H5CH3, benzene C6H6, cumene C6H5CH(CH3)2]. A copper vapour laser (wavelength 510.6 nm, pulse duration 20 ns) was used. The films were studied with x-ray Auger spectroscopy, high-energy electron diffraction, scanning electron microscopy, and Raman scattering spectroscopy. The sp3 fraction in the deposited films reached 50% — 70%, depending on the choice of hydrocarbon. The average film thickness was 100 — 200 nm and the microhardness reached 50 — 70 GPa.

  18. Theoretical investigation of superconductivity in ternary silicide NaAlSi with layered diamond-like structure

    NASA Astrophysics Data System (ADS)

    Tütüncü, H. M.; Karaca, Ertuǧrul; Srivastava, G. P.

    2016-04-01

    We have investigated the electronic structure, phonon modes and electron-phonon coupling to understand superconductivity in the ternary silicide NaAlSi with a layered diamond-like structure. Our electronic results, using the density functional theory within a generalized gradient approximation, indicate that the density of states at the Fermi level is mainly governed by Si p states. The largest contributions to the electron-phonon coupling parameter involve Si-related vibrations both in the x-y plane as well as along the z-axis in the x-z plane. Our results indicate that this material is an s-p electron superconductor with a medium level electron-phonon coupling parameter of 0.68. Using the Allen-Dynes modification of the McMillan formula we obtain the superconducting critical temperature of 6.98 K, in excellent agreement with experimentally determined value of 7 K.

  19. Pyrolytic-carbon coating in carbon nanotube foams for better performance in supercapacitors

    NASA Astrophysics Data System (ADS)

    He, Nanfei; Yildiz, Ozkan; Pan, Qin; Zhu, Jiadeng; Zhang, Xiangwu; Bradford, Philip D.; Gao, Wei

    2017-03-01

    Nowadays, the wide-spread adoption of supercapacitors has been hindered by their inferior energy density to that of batteries. Here we report the use of our pyrolytic-carbon-coated carbon nanotube foams as lightweight, compressible, porous, and highly conductive current collectors in supercapacitors, which are infiltrated with chemically-reduced graphene oxide and later compressed via mechanical and capillary forces to generate the active electrodes. The pyrolytic carbon coatings, introduced by chemical vapor infiltration, wrap around the CNT junctions and increase the surface roughness. When active materials are infiltrated, the pyrolytic-carbon coatings help prevent the π-stacking, enlarge the accessible surface area, and increase the electrical conductivity of the scaffold. Our best-performing device offers 48% and 57% higher gravimetric energy and power density, 14% and 23% higher volumetric energy and power density, respectively, and two times higher knee frequency, than the device with commercial current collectors, while the "true-performance metrics" are strictly followed in our measurements. We have further clarified the solution resistance, charge transfer resistance/capacitance, double-layer capacitance, and Warburg resistance in our system via comprehensive impedance analysis, which will shed light on the design and optimization of similar systems.

  20. Strontium and magnesium substituted dicalcium phosphate dehydrate coating for carbon/carbon composites prepared by pulsed electrodeposition

    NASA Astrophysics Data System (ADS)

    Liu, Shou-jie; Li, He-jun; Zhang, Lei-lei; Feng, Lei; Yao, Pei

    2015-12-01

    Trace elements substituted apatite coatings have received a lot of interest recently as they have many benefits. In this work, strontium and magnesium substituted DCPD (SM-DCPD) coatings were deposited on carbon/carbon (C/C) composites by pulsed electrodeposition method. The morphology, microstructure, corrosion resistance and in vitro bioactivity of the SM-DCPD coatings are analyzed. The results show that the SM-DCPD coatings exhibit a flake-like morphology with dense and uniform structure. The SM-DCPD coatings could induce the formation of apatite layers on their surface in simulated body fluid. The electrochemical test indicates that the SM-DCPD coatings can evidently decrease the corrosion rate of the C/C composites in simulated body fluid. The SM-DCPD has potential application as the bioactive coatings.

  1. The thermal conductivity of carbon coated silicon carbide fibers embedded in a silicon carbide matrix

    SciTech Connect

    Beecher, S.C.; Dinwiddie, R.B.; Lowden, R.A.

    1993-12-31

    The room temperature thermal conductivity has been measured for a series of composite materials composed of carbon coated silicon carbide (SiC) fibers embedded in a SiC matrix. The composite samples consisted of 0/30{degree} bi-directional plain weave Nicalon fibers coated with varying thicknesses of pyrolitic carbon and infiltrated with SiC by the forced flow chemical vapor infiltration process to form the matrix. The fiber volume fraction was held constant at 0.423 {plus_minus} 0.012 and the from 0.03 {mu}m to 0.983 {mu}m, with the fibers of one sample left uncoated. Results transverse to fiber direction show significant differences with the introduction and subsequent increase in the carbon coating thickness. The thermal conductivity decreased for all the coated samples compared to the uncoated sample coating thickness compared to the sample with the thinnest carbon coating.

  2. Method of producing a carbon coated ceramic membrane and associated product

    DOEpatents

    Liu, Paul K. T.; Gallaher, George R.; Wu, Jeffrey C. S.

    1993-01-01

    A method of producing a carbon coated ceramic membrane including passing a selected hydrocarbon vapor through a ceramic membrane and controlling ceramic membrane exposure temperature and ceramic membrane exposure time. The method produces a carbon coated ceramic membrane of reduced pore size and modified surface properties having increased chemical, thermal and hydrothermal stability over an uncoated ceramic membrane.

  3. Method of producing a carbon coated ceramic membrane and associated product

    DOEpatents

    Liu, P.K.T.; Gallaher, G.R.; Wu, J.C.S.

    1993-11-16

    A method is described for producing a carbon coated ceramic membrane including passing a selected hydrocarbon vapor through a ceramic membrane and controlling ceramic membrane exposure temperature and ceramic membrane exposure time. The method produces a carbon coated ceramic membrane of reduced pore size and modified surface properties having increased chemical, thermal and hydrothermal stability over an uncoated ceramic membrane. 12 figures.

  4. Arc spraying of nano-structured wire on carbon steel: examination of coating microstructures

    SciTech Connect

    Al Askandarani, A.; Hashmi, M. S. J.; Yilbas, B. S.

    2011-01-17

    Arc spraying of nano-structured wire (TAFA 95MX) onto carbon steel is carried out. The workpieces coated were heat treated at temperature similar to the operating temperature of the hot-path components of power gas turbines. The morphological and microstructural changes in the coating are examined using optical and Scanning Electron Microscope (SEM). The surface roughness and microhardness of the resulting coatings are measured. It is found that the formation of dimples like structure at surface increased the surface roughness of the coating. The microhardness of the resulting coating is significantly higher than the base material hardness. Heat treatment does not alter the microstructure and microhardness of the coating.

  5. Comparing graphene, carbon nanotubes, and superfine powdered activated carbon as adsorptive coating materials for microfiltration membranes.

    PubMed

    Ellerie, Jaclyn R; Apul, Onur G; Karanfil, Tanju; Ladner, David A

    2013-10-15

    Multi-walled carbon nanotubes (MWCNTs), nano-graphene platelets (NGPs), and superfine powdered activated carbon (S-PAC) were comparatively evaluated for their applicability as adsorptive coatings on microfiltration membranes. The objective was to determine which materials were capable of contaminant removal while causing minimal flux reduction. Methylene blue and atrazine were the model contaminants. When applied as membrane coatings, MWCNTs had minimal retention capabilities for the model contaminants, and S-PAC had the fastest removal. The membrane coating approach was also compared with a stirred vessel configuration, in which the adsorbent was added to a stirred flask preceding the membrane cell. Direct application of the adsorbent to the membrane constituted a greater initial reduction in permeate concentrations of the model contaminants than with the stirred flask setup. All adsorbents except S-PAC showed flux reductions less than 5% after application as thin-layer membrane coatings, and flux recovery after membrane backwashing was greater than 90% for all materials and masses tested.

  6. Plasma polymerized thin coating as a protective layer of carbon nanotubes grafted on carbon fibers

    NASA Astrophysics Data System (ADS)

    Einig, A.; Rumeau, P.; Desrousseaux, S.; Magga, Y.; Bai, J. B.

    2013-04-01

    Nanoparticles addition is widely studied to improve properties of carbon fiber reinforced composites. Here, hybrid carbon fiber results from grafting of carbon nanotubes (CNT) by Chemical Vapor Deposition (CVD) on the carbon fiber for mechanical reinforcement and conductive properties. Both tows and woven fabrics made of the hybrid fibers are added to the matrix for composite processing. However handling hybrid fibers may induce unwilling health risk due to eventual CNT release and a protective layer is required. A thin coating layer is deposited homogeneously by low pressure plasma polymerization of an organic monomer without modifying the morphology and the organization of grafted CNTs. The polymeric layer effect on the electrical behavior of hybrid fiber is assessed by conductivity measurements. Its influence on the mechanical properties is also studied regarding the interface adhesion between fiber and matrix. The protective role of layer is demonstrated by means of friction constraints applied to the hybrid fiber.

  7. Parametrically Optimized Carbon Nanotube-Coated Cold Cathode Spindt Arrays

    PubMed Central

    Yuan, Xuesong; Cole, Matthew T.; Zhang, Yu; Wu, Jianqiang; Milne, William I.; Yan, Yang

    2017-01-01

    Here, we investigate, through parametrically optimized macroscale simulations, the field electron emission from arrays of carbon nanotube (CNT)-coated Spindts towards the development of an emerging class of novel vacuum electron devices. The present study builds on empirical data gleaned from our recent experimental findings on the room temperature electron emission from large area CNT electron sources. We determine the field emission current of the present microstructures directly using particle in cell (PIC) software and present a new CNT cold cathode array variant which has been geometrically optimized to provide maximal emission current density, with current densities of up to 11.5 A/cm2 at low operational electric fields of 5.0 V/μm. PMID:28336845

  8. Zinc Oxide Coated Carbon Nanotubes for Energy Harvesting Applications

    NASA Astrophysics Data System (ADS)

    Mohney, Austin; Stollberg, David

    2012-02-01

    Small scale electrical devices depend on bulky batteries that require recharging or replacement. In biomedical monitoring, where sensors could be implanted inside the body, maintenance of batteries presents a problem. It would be beneficial if small scale devices could generate their own power and alleviate their dependence on batteries. Piezoelectric nanogenerators have proven themselves as a viable means for ambient energy harvesting. Piezoelectric materials, such as zinc oxide (ZnO), produce a voltage difference when subjected to mechanical strain. Manipulation of this voltage can allow for the storage of energy to power small scale devices. The objective of this research is to manufacture a piezo-generator that can transduce mechanical vibrations into electrical energy. Carbon nanotubes, selected for their strong, flexible, and conductive properties, are used as a structural backbone for a ZnO piezoelectric coating and a Ag electrode coating. A Schottky diode interface is used to rectify the current output of the device. The devices yielded an average current output of .79 microAmps. SEM imagining was used to characterize the fabrication process. A Keithley 2700 digital multimeter was used to characterize the current output of the devices.

  9. Parylene coated carbon nanotube actuators for tactile stimulation

    NASA Astrophysics Data System (ADS)

    Bubak, Grzegorz; Ansaldo, Alberto; Gendron, David; Brayda, Luca; Ceseracciu, Luca; Ricci, Davide

    2015-04-01

    Ionic liquid/carbon nanotube based actuators have been constantly improved in recent years owing to their suitability for applications related to human-machine interaction and robotics thanks to their light-weight and low voltage operation. However, while great attention has been paid to the development of better electrodes and electrolytes, no adequate efforts were made to develop actuators to be used in direct contact with the human skin. Herein, we present our approach, based on the use of parylene-C coating. Indeed, owning to its physicochemical properties such as high dielectric strength, resistance to solvents, biological and chemical inactivity/inertness, parylene fulfils the requirements for use in biocompatible actuator fabrication. In this paper, we study the influence of the parylene coating on the actuator performance. To do so, we analyzed its mechanical and electrochemical properties. We looked into the role of parylene as a protection layer that can prevent alteration of the actuator performance likely caused by external conditions. In order to complete our study, we designed a haptic device and investigated the generated force, displacement and energy usage.

  10. Chemical sensors using coated or doped carbon nanotube networks

    NASA Technical Reports Server (NTRS)

    Li, Jing (Inventor); Meyyappan, Meyya (Inventor)

    2010-01-01

    Methods for using modified single wall carbon nanotubes ("SWCNTs") to detect presence and/or concentration of a gas component, such as a halogen (e.g., Cl.sub.2), hydrogen halides (e.g., HCl), a hydrocarbon (e.g., C.sub.nH.sub.2n+2), an alcohol, an aldehyde or a ketone, to which an unmodified SWCNT is substantially non-reactive. In a first embodiment, a connected network of SWCNTs is coated with a selected polymer, such as chlorosulfonated polyethylene, hydroxypropyl cellulose, polystyrene and/or polyvinylalcohol, and change in an electrical parameter or response value (e.g., conductance, current, voltage difference or resistance) of the coated versus uncoated SWCNT networks is analyzed. In a second embodiment, the network is doped with a transition element, such as Pd, Pt, Rh, Ir, Ru, Os and/or Au, and change in an electrical parameter value is again analyzed. The parameter change value depends monotonically, not necessarily linearly, upon concentration of the gas component. Two general algorithms are presented for estimating concentration value(s), or upper or lower concentration bounds on such values, from measured differences of response values.

  11. Biomimetic apatite coatings--carbonate substitution and preferred growth orientation.

    PubMed

    Müller, Lenka; Conforto, Egle; Caillard, Daniel; Müller, Frank A

    2007-11-01

    Biomimetic apatite coatings were obtained by soaking chemically treated titanium in SBF with different HCO(3)(-) concentration. XRD, FTIR and Raman analyses were used to characterize phase composition and degree of carbonate substitution. The microstructure, elemental composition and preferred alignment of biomimetically precipitated crystallites were characterized by cross-sectional TEM analyses. According to XRD, the phase composition of precipitated coatings on chemically pre-treated titanium after exposure to SBF was identified as hydroxy carbonated apatite (HCA). A preferred c-axis orientation of the deposited crystals can be supposed due to the high relative peak intensities of the (002) diffraction line at 2theta=26 degrees compared to the 100% intensity peak of the (211) plane at 2theta=32 degrees . The crystallite size in direction of the c-axis of HCA decreased from 26 nm in SBF5 with a HCO(3)(-) concentration of 5 mmol/l to 19 nm in SBF27 with a HCO(3)(-) concentration of 27 mmol/l. Cross-sectional TEM analyses revealed that all distances correspond exactly to the hexagonal structure of hydroxyapatite. The HCO(3)(-) content in SBF also influences the composition of precipitated calcium phosphates. Biomimetic apatites were shown to have a general formula of Ca(10-x-y)Mg(y)(HPO(4))(x-z)(CO(3))(z)(PO(4))(6-x)(OH)(2-x-w)(CO(3))(w/2). According to FTIR and Raman analyses, it can be supposed that as long as the HCO(3)(-) concentration in the testing solutions is below 20 mmol/l, only B-type HCA (0

  12. Carbon-coated SnO2 nanobelts and nanoparticles by single catalytic step

    NASA Astrophysics Data System (ADS)

    Carreño, Neftali L. V.; Nunes, Michael R.; Garcia, Irene T. S.; Orlandi, Marcelo O.; Fajardo, Humberto V.; Longo, Elson

    2009-05-01

    Several types of carbon nanostructures (amorphous and graphitic), for the coating of SnO2 nanobelts and nanoparticles were obtained by a single catalytic process, during methane, natural gas, and methanol decomposition using the reactivity of surface-modified SnO2 nanostructure as a nanotemplate. The nanostructured catalyst templates were based on transition metal nanoparticles supported on SnO2 nanobelts previously prepared by a carbothermal reduction process. Carbon-coated SnO2 nanopowders were also successfully synthesized for the fabrication of carbon spheres. The carbon coating process and yield, along with the nature of the nanostructured carbon, are strongly influenced by the chemically modified surface of the SnO2 nanostructure template and the chemical reaction gas composition. The preliminary catalytic activity and gas-sensing properties of these novel materials based on metal nanoparticles and carbon-coated SnO2 were determined.

  13. METHOD FOR FORMING A COATING OF MOLYBDENUM CARBIDE ON A CARBON BODY

    DOEpatents

    Simnad, M.T.

    1962-04-01

    A method is described for coating a carbon bodywith molybdenum carbide in such a manner that the carbon body is rendered less permeable to the flow of gases and has increased resistance to corrosion and erosion. The method includes coating a carbon body with molybdenum trioxide by contacting it at a temperature below the condensation temperature with molybdenum trioxide vapors and thereafter carburizing the molybdenum trioxide in situ in an inert atmosphere on the carhon body. (AEC)

  14. Processing of fused silicide coatings for carbon-based materials

    NASA Technical Reports Server (NTRS)

    Smialek, J. L.

    1982-01-01

    The processing and oxidation resistance of fused Al-Si and Ni-Si slurry coatings on ATJ graphite was studied. Ni-Si coatings in the 70 to 90 percent Si range were successfully processed to melt, wet, and bond to the graphite. The molten coatings also infiltrated the porosity in graphite and reacted with it to form SiC in the coating. Cyclic oxidation at 1200 C showed that these coatings were not totally protective because of local attack of the substrate, due to the extreme thinness of the coatings in combination with coating cracks.

  15. Investigation of electronic structure and thermodynamic properties of quaternary Li-containing chalcogenide diamond-like semiconductors

    NASA Astrophysics Data System (ADS)

    Berarma, K.; Charifi, Z.; Soyalp, F.; Baaziz, H.; Uğur, G.; Uğur, Ş.

    2016-12-01

    Using first-principles calculations based on density functional theory, the structural, electronic and thermodynamic properties of Li2CdGeS4 and Li2CdSnS4 compounds are investigated. We confirmed that both Li2CdGeS4 and Li2CdSnS4 are diamond-like semiconductors of the wurtz-stannite structure type based on that of diamond in terms of tetrahedra volume. All the tetrahedra are almost regular with major distortion from the ideal occurring in the LiS4 tetrahedron, with values for S-Li-S ranging from 105.69° to 112.84° in the Li2CdGeS4 compound. Furthermore, the Cd-S bond possesses a stronger covalent bonding strength than the Li/Ge-S bonds. In addition, the inter-distances in Li2CdSnS4 show a larger spread than the distances in the Li2CdGeS4 compound. The electronic structures have been calculated to understand the bonding mechanism in quaternary Li-containing chalcogenide diamond-like semiconductors. Our results show that Li2CdGeS4 and Li2CdSnS4 are semiconductors with a direct band gap of 2.79 and 2.42 eV and exhibit mixed ionic-covalent bonding. It is also noted that replacing Ge by Sn leads to a decrease in the band gap; this behavior is explained in terms of bond lengths and electronegativity differences between atoms. Optical properties, including the dielectric function, reflectivity, and absorption coefficient, each as a function of photon energy are calculated and show an optical anisotropy for Li2CdGeS4 and Li2CdSnS4. The static dielectric constant {\\varepsilon }1(0) and static refractive index n(0) decrease when Ge is replaced by Sn. The influence of pressures and temperatures on the thermodynamic properties like the specific heat at constant volume {C}v, and at constant pressure {C}p, the Debye temperature {{{\\Theta }}}{{D}}, the entropy S and the Grüneisen parameter γ have been predicted at enlarged pressure and temperature ranges. The principal aspect from the obtained results is the close similarity of both compounds.

  16. Investigation of interfacial interaction between uncoated and coated carbon fibres and the magnesium alloy AZ91.

    PubMed

    Dorner-Reisel, A; Nishida, Y; Klemm, V; Nestler, K; Marx, G; Müller, E

    2002-10-01

    Unidirectionally reinforced metal-matrix composites with a fibre volume content between 63 and 68% were processed by squeeze casting using T800 H carbon fibres and the magnesium alloy AZ91. The surface of the fibres was prepared by thermal desizing of the fibres or by deposition of a pyrolytic carbon (pyC) coating. Different interfacial conditions could be identified by transmission electron microscopy (TEM) and the single-fibre push-in test. TEM confirmed the formation of needle-like phases at the fibre surface or, for coated fibres, within the pyrolytic carbon coating. During loading by the Vickers type indenter an intense response was observed for composites of coated fibres and the magnesium alloy. This could by caused by stick-slip effects within the pyrolytic carbon coating.

  17. Fe3O4/carbon coated silicon ternary hybrid composite as supercapacitor electrodes

    NASA Astrophysics Data System (ADS)

    Oh, Ilgeun; Kim, Myeongjin; Kim, Jooheon

    2015-02-01

    In this study, Fe3O4/carbon-coated Si ternary hybrid composites were fabricated. A carbon layer was directly formed on the surface of Si by the thermal vapor deposition. The carbon-coating layer not only prevented the contact between Si and reactive electrolyte but also provided anchoring sites for the deposition of Fe3O4. Fe3O4 nanoparticles were deposited on the surface of carbon-coated Si by the hydrazine reducing method. The morphology and structure of Fe3O4 and carbon layer were characterized via X-ray diffractometry, field emission scanning electron microscopy, field emission transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analyses. These characterizations indicate that a carbon layer was fully coated on the Si particles, and Fe3O4 particles were homogeneously deposited on the carbon-coated Si particles. The Fe3O4/carbon-coated Si electrode exhibited enhanced electrochemical performance, attributed to the high conductivity and stability of carbon layer and pseudocapacitive reaction of Fe3O4. The proposed ternary-hybrid composites may be potentially useful for the fabrication of high-performance electrodes.

  18. CARBON COATED (CARBONOUS) CATALYST IN EBULLATED BED REACTOR FOR PRODUCTION OF OXYGENATED CHEMICALS FROM SYNGAS/CO2

    SciTech Connect

    Peizheng Zhou

    2002-12-30

    This report summarizes the work completed under DOE's Support of Advanced Fuel Research program, Contract No. DE-FG26-99FT40681. The contract period was October 2000 through September 2002. This R&D program investigated the modification of the mechanical strength of catalyst extrudates using Hydrocarbon Technologies, Inc. (HTI) carbon-coated catalyst technology so that the ebullated bed technology can be utilized to produce valuable oxygenated chemicals from syngas/CO{sub 2} efficiently and economically. Exothermic chemical reactions benefit from the temperature control and freedom from catalyst fouling provided by the ebullated bed reactor technology. The carbon-coated extrudates prepared using these procedures had sufficient attrition resistance and surface area for use in ebullated bed operation. The low cost of carbon coating makes the carbon-coated catalysts highly competitive in the market of catalyst extrudates.

  19. Mixed polyvalent-monovalent metal coating for carbon-graphite fibers

    NASA Technical Reports Server (NTRS)

    Harper-Tervet, J.; Tervet, F. W.; Humphrey, M. F. (Inventor)

    1982-01-01

    An improved coating of gasification catalyst for carbon-graphite fibers is provided comprising a mixture of a polyvalent metal such as calcium and a monovalent metal such as lithium. The addition of lithium provides a lighter coating and a more flexible coating when applied to a coating of a carboxyl containing resin such as polyacrylic acid since it reduces the crosslink density. Furthermore, the presence of lithium provides a glass-like substance during combustion which holds the fiber together resulting in slow, even combustion with much reduced evolution of conductive fragments. The coated fibers are utilized as fiber reinforcement for composites.

  20. Dielectric properties of WS2-coated multiwalled carbon nanotubes studied by energy-loss spectroscopic profiling

    NASA Astrophysics Data System (ADS)

    Stolojan, Vlad; Silva, S. R. P.; Goringe, Michael J.; Whitby, R. L. D.; Hsu, Wang K.; Walton, D. R. M.; Kroto, Harold W.

    2005-02-01

    We investigate experimentally the electronic properties of the coating for multiwalled carbon nanotubes covered in tungsten disulfide (WS2) of various thicknesses. Coatings of thicknesses between 2 and 8 monolayers (ML) are analyzed using energy-loss spectroscopic profiling (ELSP), by studying the variations in the plasmon excitations across the coated nanotube, as a function of the coating thickness. We find a change in the ELSP for coatings above 5 ML thickness, which we interpret in terms of a change in its dielectric properties.

  1. Carbon fiber CVD coating by carbon nanostructured for space materials protection against atomic oxygen

    NASA Astrophysics Data System (ADS)

    Pastore, Roberto; Bueno Morles, Ramon; Micheli, Davide

    2016-07-01

    adhesion and durability in the environment. Though these coatings are efficient in protecting polymer composites, their application imposes severe constraints. Their thermal expansion coefficients may differ markedly from those of polymer composite substrates: as a result, cracks develop in the coatings on thermal cycling and AO can penetrate through them to the substrate. In addition to the technicalities of forming an effective barrier, such factors as cost, convenience of application and ease of repair are important considerations in the selection of a coating for a particular application. The latter issues drive the aerospace research toward the development of novel light composite materials, like the so called polymer nanocomposites, which are materials with a polymer matrix and a filler with at least one dimension less than 100 nanometers. Current interest in nanocomposites has been generated and maintained because nanoparticle-filled polymers exhibit unique combinations of properties not achievable with traditional composites. These combinations of properties can be achieved because of the small size of the fillers, the large surface area the fillers provide, and in many cases the unique properties of the fillers themselves. In particular, the carbon fiber-based polymeric composite materials are the basic point of interest: the aim of the present study is to find new solution to produce carbon fiber-based composites with even more upgraded performances. One intriguing strategy to tackle such an issue has been picked out in the coupling between the carbon fibers and the carbon nanostructures. That for two main reasons: first, carbon nanostructures have shown fancy potentialities for any kind of technological applications since their discovery, second, the chemical affinity between fiber and nanostructure (made of the same element) should be a likely route to approach the typical problems due to thermo-mechanical compatibility. This work is joined in such framework

  2. Optical properties of black carbon aggregates with non-absorptive coating

    NASA Astrophysics Data System (ADS)

    Liu, Chao; Li, Ji; Yin, Yan; Zhu, Bin; Feng, Qian

    2017-01-01

    This study develops an idealized model to account for the effects of non-absorptive coating on the optical properties of black carbon (BC) aggregates. The classic fractal aggregate is applied to represent realistic BC particles, and the coating is assumed to be spherical. To accelerate the single-scattering simulation, BC monomers that were overlapped with coating sphere (not those completely inside the coating) are slightly moved to avoid overlapping. The multiple-sphere T-matrix method (MSTM) becomes applicable to calculate the optical properties of inhomogeneous particles with any coating amount, and is generally two orders of magnitude faster than the discrete-dipole approximation for particles we considered. Furthermore, the simple spherical coating is found to have similar effects on the optical properties to those based on more complicated coating structure. With the simple particle model and the efficient MSTM, it becomes possible to consider the influence of coating with much more details. The non-absorptive coating of BC aggregates can significantly enhance BC extinction and absorption, which is consistent with previous studies. The absorption of coated aggregates can be over two times stronger than that of BC particles without coating. Besides the coating volume, the relative position between the mass centers of BC aggregate and coating also plays an important role on the optical properties, and should obviously be considered in further studies.

  3. Effects of Coatings on Laser-Induced Incandescence Measurements of Black Carbon

    NASA Astrophysics Data System (ADS)

    Michelsen, H. A.; Dansson, M. A.; Schrader, P. E.; Metcalf, A. R.; Lopez-Yglesias, X.; Bambha, R.

    2012-12-01

    In exhaust plumes and the ambient atmosphere, refractory black carbon particles are often coated with unburned fuel, sulfuric acid, water, ash, and other combustion by-products and atmospheric constituents. These coatings can have an effect on particle optical and physical properties and can thus have an influence on optical diagnostics applied to coated particles. The effects of particle coatings therefore need to be fully understood in order to apply optical diagnostics under a wide range of conditions. We have investigated the effects of coatings on time-resolved laser induced incandescence (LII) measurements of combustion-generated black carbon particles. Particles were generated in a coflow diffusion flame, extracted, cooled, and coated with oleic acid. A thermodenuder was used to remove the coating. A scanning mobility particle sizer (SMPS) was used to monitor aggregate sizes, a centrifugal particle mass analyzer (CPMA) was used to measure coating mass fractions, and transmission electron microscopy (TEM) was used to characterize particle morphologies. The results demonstrate striking differences in LII temporal evolution and dependence on laser fluence between coated and uncoated particles. The LII signal appears to be sensitive to coating-induced particle morphology and optical changes. These results can be understood in the context of energy and mass balance during laser heating and conductive and evaporative cooling and are consistent with predictions based on an LII model that includes a heavy organic coating.

  4. Electromagnetic Wave Shieding Effectiveness of Carbon Fiber Sheet Coated Ferrite Film by Microwave-Hydrothermal Process

    NASA Astrophysics Data System (ADS)

    Murakami, Ri Ichi; Yamamoto, Hidetoshi; Kim, Chan Kong; Yim, Cheol Mun; Kim, Yun Hae

    The developments of electromagnetic wave shielding materials are strongly required because the malfunction of electronic equipment, mobile phone and wireless LAN avoids. In this study, it was investigated that the electromagnetic shielding effectiveness of carbon fiber sheets were enhanced by the ferrite which was coated by the microwave hydrothermal process. For coated carbon fiber sheet, the effects of ferrite and lamination of carbon fiber textile on the electromagnetic wave shielding effectiveness were discussed. In the range of frequency (100 1 GHz), the electromagnetic wave shielding effectiveness was measured by using TEM-Cell. The electromagnetic wave shielding effectiveness was greater for the coated carbon fiber sheets than for the uncoated carbon fiber sheets. When the insulation film was located between two carbon fiber sheets, the electromagnetic wave shielding effectiveness increased.

  5. Protection of nuclear graphite toward liquid fluoride salt by isotropic pyrolytic carbon coating

    NASA Astrophysics Data System (ADS)

    He, Xiujie; Song, Jinliang; Xu, Li; Tan, Jie; Xia, Huihao; Zhang, Baoliang; He, Zhoutong; Gao, Lina; Zhou, Xingtai; Zhao, Mingwen; Zhu, Zhiyong; Bai, Shuo

    2013-11-01

    Infiltration studies were performed on uncoated nuclear graphite and isotropic pyrolytic carbon (PyC) coated graphite in molten FLiNaK salt at 650 °C under argon atmosphere at 1, 3 and 5 atm. Uncoated graphite shows weight gain more obviously than that of PyC coated graphite. Nuclear graphite with PyC coating exhibits excellent infiltration resistance in molten salt due to the small open porosity as conformed from scanning electron microscopy and mercury injection experiments.

  6. Effects of temperature on internal friction of Graphit-iC graphite-like carbon coatings

    NASA Astrophysics Data System (ADS)

    Zhu, Zhi-yong; Shi, Wen; Wan, Zi; Yuan, Jun-feng; Li, Xiao

    2013-12-01

    Graphit-iC graphite-like carbon coatings were deposited on SDC90 cold work die steel by using an unbalanced magnetron sputtering technology. Effects of the temperature on microstructure and internal friction of the carbon coatings were characterized by Raman spectroscopy (Raman) and a low-frequency mechanical analyzer (LMA-1) testing system. The results indicate that the internal friction of the two-side deposited carbon coatings is small (2.17×10-4), being higher than one of the substrate (1.63×10-4), and increases with temperature. However, there is an internal friction peak at 250°C accompanied with partial sp3 transferred to sp2 and increasing the intensity ratio ID/IG. There is gradual graphitization tendency of the carbon coatings as temperatures increase from 25°C to 350 °C. This would be progressive transformation from amorphous to crystalline.

  7. Optically and biologically active mussel protein-coated double-walled carbon nanotubes.

    PubMed

    Jung, Yong Chae; Muramatsu, Hiroyuki; Fujisawa, Kazunori; Kim, Jin Hee; Hayashi, Takuya; Kim, Yoong Ahm; Endo, Morinobu; Terrones, Mauricio; Dresselhaus, Mildred S

    2011-12-02

    A method of dispersing strongly bundled double-walled carbon nanotubes (DWNTs) via a homogeneous coating of mussel protein in an aqueous solution is presented. Optical activity, mechanical strength, as well as electrical conductivity coming from the nanotubes and the versatile biological activity from the mussel protein make mussel-coated DWNTs promising as a multifunctional scaffold and for anti-fouling materials.

  8. Morphological and microstructural studies on aluminizing coating of carbon steel

    SciTech Connect

    Samsu, Zaifol; Othman, Norinsan Kamil; Daud, Abd Razak; Hussein, Hishammuddin

    2013-11-27

    Hot dip aluminizing is one of the most effective methods of surface protection for steels and is gradually gaining popularity. The morphology and microstructure of an inter-metallic layer form on the surface of low carbon steel by hot dip aluminization treatment had been studied in detail. This effect has been investigated using optical and scanning electron microscopy, and X-ray diffraction. The result shows that the reaction between the steel and the molten aluminium leads to the formation of Fe–Al inter-metallic compounds on the steel surface. X-ray diffraction and electron microscopic studies showed that a two layer coating was formed consisting of an external Al layer and a (Fe{sub 2}Al{sub 5}) inter metallic on top of the substrate after hot dip aluminizing process. The inter-metallic layer is ‘thick’ and exhibits a finger-like growth into the steel. Microhardness testing shown that the intermetallic layer has high hardness followed by steel substrate and the lowest hardness was Al layer.

  9. Depth profiling analysis of solar wind helium collected in diamond-like carbon film from Genesis

    SciTech Connect

    Bajo, Ken-ichi; Olinger, Chad T.; Jurewicz, Amy J.G.; Burnett, Donald S.; Sakaguchi, Isao; Suzuki, Taku; Itose, Satoru; Ishihara, Morio; Uchino, Kiichiro; Wieler, Rainer; Yurimoto, Hisayoshi

    2015-01-01

    The distribution of solar-wind ions in Genesis mission collectors, as determined by depth profiling analysis, constrains the physics of ion solid interactions involving the solar wind. Thus, they provide an experimental basis for revealing ancient solar activities represented by solar-wind implants in natural samples. We measured the first depth profile of ⁴He in a collector; the shallow implantation (peaking at <20 nm) required us to use sputtered neutral mass spectrometry with post-photoionization by a strong field. The solar wind He fluence calculated using depth profiling is ~8.5 x 10¹⁴ cm⁻². The shape of the solar wind ⁴He depth profile is consistent with TRIM simulations using the observed ⁴He velocity distribution during the Genesis mission. It is therefore likely that all solar-wind elements heavier than H are completely intact in this Genesis collector and, consequently, the solar particle energy distributions for each element can be calculated from their depth profiles. Ancient solar activities and space weathering of solar system objects could be quantitatively reproduced by solar particle implantation profiles.

  10. Voltage assisted asymmetric nanoscale wear on ultra-smooth diamond like carbon thin films at high sliding speeds.

    PubMed

    Rajauria, Sukumar; Schreck, Erhard; Marchon, Bruno

    2016-05-06

    The understanding of tribo- and electro-chemical phenomenons on the molecular level at a sliding interface is a field of growing interest. Fundamental chemical and physical insights of sliding surfaces are crucial for understanding wear at an interface, particularly for nano or micro scale devices operating at high sliding speeds. A complete investigation of the electrochemical effects on high sliding speed interfaces requires a precise monitoring of both the associated wear and surface chemical reactions at the interface. Here, we demonstrate that head-disk interface inside a commercial magnetic storage hard disk drive provides a unique system for such studies. The results obtained shows that the voltage assisted electrochemical wear lead to asymmetric wear on either side of sliding interface.

  11. Voltage assisted asymmetric nanoscale wear on ultra-smooth diamond like carbon thin films at high sliding speeds

    NASA Astrophysics Data System (ADS)

    Rajauria, Sukumar; Schreck, Erhard; Marchon, Bruno

    2016-05-01

    The understanding of tribo- and electro-chemical phenomenons on the molecular level at a sliding interface is a field of growing interest. Fundamental chemical and physical insights of sliding surfaces are crucial for understanding wear at an interface, particularly for nano or micro scale devices operating at high sliding speeds. A complete investigation of the electrochemical effects on high sliding speed interfaces requires a precise monitoring of both the associated wear and surface chemical reactions at the interface. Here, we demonstrate that head-disk interface inside a commercial magnetic storage hard disk drive provides a unique system for such studies. The results obtained shows that the voltage assisted electrochemical wear lead to asymmetric wear on either side of sliding interface.

  12. Characterization of Diamond Like Carbon Thin Films Fabricated by Unbalanced Magnetron Sputtering under Ultra-High Vacuum Conditions

    NASA Astrophysics Data System (ADS)

    Cooper, Kevin W.

    DLC thin films were fabricated under high vacuum and ultra-high vacuum conditions using Type II UBM sputtering with a graphite target. Ultra-high purity argon sputtering gas at nominally 2.8 - 3.0 mtorr was used as a working gas during deposition. Film thickness and elemental composition was determined through a combination of Rutherford Backscattering and Forward Recoil Elastic Scattering spectroscopy at Ohio University using the 4.5 MV tandem particle accelerator at Edwards Accelerator Laboratory. Electronic characterization of the films consisted of measurements of room and low temperature current-voltage curves, temperature dependent conductivity, Seebeck coefficient, and the temperature dependent Seebeck coefficient. Hydrogen concentration profiles of the films indicated a three layer structure: surface, bulk, and interface. Total hydrogen concentration in the film was reduced to ≈3 at.% for the films with lowest hydrogen content. This low-level of hydrogen content was achieved through UHV base chamber pressure, pre-sputtering of the graphite target, and the use of a hydrogen filter on the UHP argon supply line. The films exhibited linear current-voltage relations in both high and low temperature regimes. A thermally assisted conduction relationship in temperature dependent conductivity was observed. Nominal film conductivity was measured to be ≈2 - 3 S/cm.. Measurements of the Seebeck coefficient indicated a p-type material with values of the coefficient ≈10 muV/K. The Seebeck coefficient was found to have a weak linear dependence on temperature indicative of a diffusive thermopower relationship. Measurements of the electronic properties as a function of hydrogen concentration indicated at most a weak relationship over the range of the low hydrogen concentrations in this work.

  13. Low-frequency Raman and Brillouin spectroscopy from graphite, diamond and diamond-like carbons, fullerenes and nanotubes.

    PubMed

    Beghi, M G; Bottani, C E

    2004-11-15

    Inelastic light scattering by acoustic phonons (Brillouin scattering) is a useful tool for probing material properties at the submicrometre scale. In media which are statistically homogeneous at this scale, it gives access to the acoustic properties and the elastic moduli. In nanostructures it probes the vibrational properties at the mesoscopic scale. Applications to carbonaceous materials are reviewed.

  14. Voltage assisted asymmetric nanoscale wear on ultra-smooth diamond like carbon thin films at high sliding speeds

    PubMed Central

    Rajauria, Sukumar; Schreck, Erhard; Marchon, Bruno

    2016-01-01

    The understanding of tribo- and electro-chemical phenomenons on the molecular level at a sliding interface is a field of growing interest. Fundamental chemical and physical insights of sliding surfaces are crucial for understanding wear at an interface, particularly for nano or micro scale devices operating at high sliding speeds. A complete investigation of the electrochemical effects on high sliding speed interfaces requires a precise monitoring of both the associated wear and surface chemical reactions at the interface. Here, we demonstrate that head-disk interface inside a commercial magnetic storage hard disk drive provides a unique system for such studies. The results obtained shows that the voltage assisted electrochemical wear lead to asymmetric wear on either side of sliding interface. PMID:27150446

  15. Behavior of Plasma-Sprayed Hydroxyapatite Coatings onto Carbon/carbon Composites in Simulated Body Fluid

    NASA Astrophysics Data System (ADS)

    Sui, Jin-Ling; Bo, Wu; Hai, Zhou; Cao, Ning; Li, Mu-Sen

    Two types of hydroxyapatite (HA) coatings onto carbon/carbon composite (C/C composites) substrates, deposited by plasma spraying technique, were immersed in a simulated body fluid (SBF) in order to determine their behavior in conditions similar to the human blood plasma. Calcium ion concentration, pH value, microstructure, and phase compositions were analyzed. Results demonstrated that both the crystal Ca-P phases or the amorphous HA do dissolve slightly, and the dissolution of CaO phases in SBF was evident after 1 day of soaking. The calcium-ion concentration was decreased and the pH value of SBF was increased with the increasing of the immersing time. The precipitation was mainly composed of HA, which was verified by X-ray diffraction (XRD) and electron-probe microanalyzer.

  16. Investigation of surface finishing of carbon based coated tools for dry deep drawing of aluminium alloys

    NASA Astrophysics Data System (ADS)

    Steiner, J.; Andreas, K.; Merklein, M.

    2016-11-01

    Global trends like growing environmental awareness and demand for resource efficiency motivate an abandonment of lubricants in metal forming. However, dry forming evokes increased friction and wear. Especially, dry deep drawing of aluminum alloys leads to intensive interaction between tool and workpiece due to its high adhesion tendency. One approach to improve the tribological behavior is the application of carbon based coatings. These coatings are characterized by high wear resistance. In order to investigate the potential of carbon based coatings for dry deep drawing, friction and wear behavior of different coating compositions are evaluated in strip drawing tests. This setup is used to model the tribological conditions in the flange area of deep drawing operations. The tribological behavior of tetrahedral amorphous (ta-C) and hydrogenated amorphous carbon coatings with and without tungsten modification (a-C:H:W, a-C:H) is investigated. The influence of tool topography is analyzed by applying different surface finishing. The results show reduced friction with decreased roughness for coated tools. Besides tool topography the coating type determines the tribological conditions. Smooth tools with ta-C and a-C:H coatings reveal low friction and prevent adhesive wear. In contrast, smooth a-C:H:W coated tools only lead to slight improvement compared to rough, uncoated specimen.

  17. COATED CARBON ELEMENT FOR USE IN NUCLEAR REACTORS AND THE PROCESS OF MAKING THE ELEMENT

    DOEpatents

    Pyle, R.J.; Allen, G.L.

    1963-01-15

    S>This patent relates to a carbide-nitride-carbide coating for carbon bodies that are to be subjected to a high temperature nuclear reactor atmosphere, and a method of applying the same. This coating is a highly efficient diffusion barrier and protects the C body from corrosion and erosion by the reactor atmosphere. Preferably, the innermost coating is Zr carbide, the middle coatlng is Zr nitride, and the outermost coating is a mixture of Zr and Nb carbide. The nitride coating acts as a diffusion barrier, while the innermost carbide bonds the nitride to the C body and prevents deleterious reaction between the nitride and C body. The outermost carbide coating protects the nitride coating from the reactor atmosphere. (AEC)

  18. Hierarchical, titania-coated, carbon nanofibrous material derived from a natural cellulosic substance.

    PubMed

    Liu, Xiaoyan; Gu, Yuanqing; Huang, Jianguo

    2010-07-12

    Hierarchical, titania-coated, nanofibrous, carbon hybrid materials were fabricated by employing natural cellulosic substances (commercial filter paper) as a scaffold and carbon precursor. Ultrathin titania films were firstly deposited by means of a surface sol-gel process to coat each nanofiber in the filter paper, and successive calcination treatment under nitrogen atmosphere yielded the titania-carbon composite possessing the hierarchical morphologies and structures of the initial paper. The ultrathin titania coating hindered the coalescence effect of the carbon species that formed during the carbonization process of cellulose, and the original cellulose nanofibers were converted into porous carbon nanofibers (diameters from tens to hundreds of nanometers, with 3-6 nm pores) that were coated with uniform anatase titania thin films (thickness approximately 12 nm, composed of anatase nanocrystals with sizes of approximately 4.5 nm). This titania-coated, nanofibrous, carbon material possesses a specific surface area of 404 m(2) g(-1), which is two orders of magnitude higher than the titania-cellulose hybrid prepared by atomic layer deposition of titania on the cellulose fibers of filter paper. The photocatalytic activity of the titania-carbon composite was evaluated by the improved photodegradation efficiency of different dyes in aqueous solutions under high-pressure, fluorescent mercury-lamp irradiation, as well as the effective photoreduction performance of silver cations to silver nanoparticles with ultraviolet irradiation.

  19. Carbon-coated Zinc Sulfide nano-clusters: synthesis, photothermal conversion and adsorption properties.

    PubMed

    Bao, Chunlin; Zhu, Guoxing; Shen, Mengqi; Yang, Jing

    2014-12-15

    Carbon-coated cluster-like ZnS nanospheres were synthesized by a facile solvothermal route. ZnCl2, thiourea, and glucose were selected as the raw materials. The formed ZnS with hexagonal phase has spherical cluster-like structure, which shows good monodispersity in size. A thin layer carbon is coated on the surface of ZnS cluster-like spheres. The thickness of carbon shell is dependent on the dosage of glucose. The carbon-coated ZnS nano-clusters show the same emission as that of pristine ZnS nano-clusters. Exposure of the aqueous dispersion of carbon-coated ZnS products to 980 nm laser can elevate its temperature by 5.1°C in 8 min. It was found that the photothermal conversion effect mainly comes from the carbon component and at the same time, the heterointerface between ZnS and carbon also provides a positive role for it. In addition, the carbon-coated ZnS products can absorb dye molecular with highest adsorption capacity of 36.8 mg/g toward Rhodamine B. The present finding demonstrates their potential applications in photothermal agents, adsorbents, and related fields.

  20. Carbon-coated Si nanoparticles dispersed in carbon nanotube networks as anode material for lithium-ion batteries.

    PubMed

    Xue, Leigang; Xu, Guanjie; Li, Ying; Li, Shuli; Fu, Kun; Shi, Quan; Zhang, Xiangwu

    2013-01-01

    Si has the highest theoretical capacity among all known anode materials, but it suffers from the dramatic volume change upon repeated lithiation and delithiation processes. To overcome the severe volume changes, Si nanoparticles were first coated with a polymer-driven carbon layer, and then dispersed in a CNT network. In this unique structure, the carbon layer can improve electric conductivity and buffer the severe volume change, whereas the tangled CNT network is expected to provide additional mechanical strength to maintain the integrity of electrodes, stabilize the electric conductive network for active Si, and eventually lead to better cycling performance. Electrochemical test result indicates the carbon-coated Si nanoparticles dispersed in CNT networks show capacity retention of 70% after 40 cycles, which is much better than the carbon-coated Si nanoparticles without CNTs.

  1. Influence of flow rate on different properties of diamond-like nanocomposite thin films grown by PECVD

    NASA Astrophysics Data System (ADS)

    Santra, T. S.; Bhattacharyya, T. K.; Tseng, F. G.; Barik, T. K.

    2012-06-01

    Diamond-like nanocomposite (DLN) thin films were deposited on pyrex glass substrate using different flow rate of haxamethyldisiloxane (HMDSO) based liquid precursor with nitrogen gas as a glow discharged decomposition by plasma enhanced chemical vapor deposition (PECVD) technique. The significant influence of different precursor flow rates on refractive index and thickness of the DLN films was measured by using spectroscopic filmatrics and DEKTAK profilometer. Optical transparency of the DLN thin films was analyzed by UV-VIS-NIR spectrometer. FTIR spectroscopy, provides the information about shifted bonds like SiC2, Si-C, Si-O, C-C, Si-H, C-H, N-H, and O-H with different precursor flow rate. We have estimated the hardness of the DLN films from Raman spectroscopy using Gaussian deconvolution method and tried to investigate the correlation between hardness, refractive index and thickness of the films with different precursor flow rates. The composition and surface morphology of the DLN films were investigated by X-ray photo electron spectroscopy (XPS) and atomic force microscopy (AFM) respectively. We have analyzed the hardness by intensity ratio (ID/IG) of D and G peaks and correlates with hardness measurement by nanoindentation test where hardness increases from 27.8 μl/min to 80.6μl/min and then decreases with increase of flow rate from 80.6μl/min to 149.5μl/min. Finally, we correlates different parameters of structural, optical and tribological properties like film-thickness, refractive index, light transmission, hardness, surface roughness, modulus of elasticity, contact angle etc. with different precursor flow rates of DLN films.

  2. Influence of carbon nanotubes coatings onto carbon fiber by oxidative treatments combined with electrophoretic deposition on interfacial properties of carbon fiber composite

    NASA Astrophysics Data System (ADS)

    Deng, Chao; Jiang, Jianjun; Liu, Fa; Fang, Liangchao; Wang, Junbiao; Li, Dejia; Wu, Jianjun

    2015-12-01

    To improve the interfacial performance of carbon fiber (CF) and epoxy resin, carbon nanotubes (CNTs) coatings were utilized to achieve this purpose through coating onto CF by the treatment with hydrogen peroxide and concentrated nitric acid combined with electrophoretic deposition (EPD) process. The influence of electrophoretically deposited CNTs coatings on the surface properties of CFs were investigated by Fourier transform infrared spectrometer, atomic force microscopy, scanning electron microscopy and dynamic contact angle analysis. The results indicated that the deposition of carbon nanotubes introduced some polar groups to carbon fiber surfaces, enhanced surface roughness and changed surface morphologies of carbon fibers. Surface wettability of carbon fibers may be significantly improved by increasing surface free energy of the fibers due to the deposition of CNTs. The thickness and density of the coatings increases with the introduction of pretreatment of the CF during the EPD process. Short beam shear test was performed to examine the effect of carbon fiber functionalization on mechanical properties of the carbon fiber/epoxy resin composites. The interfacial adhesion of CNTs/CF reinforced epoxy composites showed obvious enhancement of interlaminar shear strength by 60.2% and scanning electron microscope photographs showed that the failure mode of composites was changed after the carbon fibers were coated with CNTs.

  3. Carbon-coated LiFePO4-porous carbon composites as cathode materials for lithium ion batteries.

    PubMed

    Ni, Haifang; Liu, Jinkun; Fan, Li-Zhen

    2013-03-07

    This work introduces a facile strategy for the synthesis of carbon-coated LiFePO(4)-porous carbon (C-LiFePO(4)-PC) composites as a cathode material for lithium ion batteries. The LiFePO(4) particles obtained are about 200 nm in size and homogeneously dispersed in porous carbon matrix. These particles are further coated with the carbon layers pyrolyzed from sucrose. The C-LiFePO(4)-PC composites display a high initial discharge capacity of 152.3 mA h g(-1) at 0.1 C, good cycling stability, as well as excellent rate capability (112 mA h g(-1) at 5 C). The likely contributing factors to the excellent electrochemical performance of the C-LiFePO(4)-PC composites could be related to the combined effects of enhancement of conductivity by the porous carbon matrix and the carbon coating layers. It is believed that further carbon coating is a facile and effective way to improve the electrochemical performance of LiFePO(4)-PC.

  4. Vacuum arc deposited DLC based coatings

    SciTech Connect

    Monteiro, Othon R.; Delplancke-Ogletree, Marie-Paule

    2002-05-01

    The great interest in the use of diamond-like carbon (DLC) films as a coating material is justified by the superior wear resistance and hardness, chemical inertness, and very low friction coefficients of these coatings. Vacuum arc deposition is well suited to prepare superhard films with high sp{sup 3}/sp{sup 2} ratios. However, the high level of internal stresses originating during growth prevents the deposition of thick films, and their hardness makes it difficult for DLC layers to comply with substrate deformations. In order to overcome these limitations, different approaches are possible. Multilayer structures are one means to maintain the surface mechanical properties of the DLC while relieving the internal stresses. Another possibility is to dope the DLC films in order to reduce the internal stress and to stabilize the desirable sp{sup 3} bonds to higher temperatures. At higher doses of dopants, the formation of nanocrystals is possible and the properties of the coatings change drastically. All these approaches were investigated on films prepared by cathodic arc and a synthesis of the results is presented here.

  5. Corrosion behavior of modified nano carbon black/epoxy coating in accelerated conditions

    NASA Astrophysics Data System (ADS)

    Ghasemi-Kahrizsangi, Ahmad; Shariatpanahi, Homeira; Neshati, Jaber; Akbarinezhad, Esmaeil

    2015-03-01

    The electrochemical behavior and anticorrosion properties of modified carbon black (CB) nanoparticles in epoxy coatings were investigated in accelerated conditions. Nanoparticles of CB were modified by sodium dodecyl sulfate (SDS) as surfactant. Dispersion of nanoparticles into epoxy was confirmed by Transmission Electron Microscopy (TEM). The accelerated condition was prepared at 65 °C. CB nanoparticles improved corrosion resistance of the epoxy coating. The optimum concentration of CB in the epoxy coating was 0.75 wt%. Results showed that the CB hinder the corrosion due to its barrier properties. CB can decrease the diffusion coefficient of water in the coating with filling the micropores.

  6. Investigation on anti-corrosion property of nano-TiO2 fluoro-carbon coatings

    NASA Astrophysics Data System (ADS)

    Qi, Yu-hong; Zhang, Zhan-ping; Wang, Li-li; Du, Xue-peng

    2009-07-01

    To meet the need of long-term anticorrosive protection of steel, a heavy-duty anticorrosive coating systems was developed with Fluorocarbon top paint which was modified by nano-TiO2. The corrosive characteristics of low carbon steel coated with the system were investigated in seawater by the exposition tests and Electrochemical Impedance Spectroscopy (EIS). The results show that the protective system with fluorocarbon top coating modified by nano-TiO2 has much better endurance than the reference system with fluorocarbon top coating not modified by nano-TiO2. There isn't any rusting and blistering on the surface of former coating, the coating system remains in "GOOD" condition. But some rusting and blistering were found on the surface of reference coating. EIS results indicated that the impedance of the nano-coating system decreases much less than that of the reference one. The nano-coating system is hopeful to meet the need of new coatings standard and to provide a target useful coating life of 15 years for ship's ballast.

  7. Coherent coexistence of nanodiamonds and carbon onions in icosahedral core-shell particles

    SciTech Connect

    Shevchenko, Vladimir Ya. Madison, Alexey E.; Mackay, Alan L.

    2007-03-01

    In icosahedral carbon nanoparticles, the diamond-like core can undergo a reversible topological transition into and coexist coherently with the onion shells. The general approach for describing and designing complex hierarchical icosahedral structures is discussed. Structural models of icosahedral carbon nanoparticles in which the local arrangement of atoms is virtually identical to that in diamond are derived. It is shown that icosahedral diamond-like particles can be transformed into onion-like shell structures (and vice versa) by the consecutive smoothing (puckering) of atomic networks without disturbance of their topological integrity. The possibility of coherent coexistence of icosahedral diamond-like core with onion shells is shown.

  8. Enhancing the performances of Li-ion batteries by carbon-coating: present and future.

    PubMed

    Li, Huiqiao; Zhou, Haoshen

    2012-01-30

    With progress of knowledge of electrode materials, it has been found that their surface structures are of great importance to the electrochemical performance of Li-ion batteries. Carbon coating can effectively increase the electrode conductivity, improve the surface chemistry of the active material, and protect the electrode from direct contact with electrolyte, leading to enhanced cycle life of the batteries. Carbon coating together with nanotechnology provides good conductivity as well as fast Li-ion diffusion, and thus also results in good rate capabilities. The recent development of carbon coating techniques in lithium-ion batteries is discussed with detailed examples of typical cathode and anode materials. The limitation of current technology and future perspective of the new concept of "hybrid coating" are also pointed out.

  9. Carbon coatings with olive oil, soybean oil and butter on nano-LiFePO 4

    NASA Astrophysics Data System (ADS)

    Kim, Ketack; Jeong, Ji Hwa; Kim, Ick-Jun; Kim, Hyun-Soo

    Kitchen oils (olive, soybean and butter) are selected for carbon coatings on LiFePO 4. The surface properties of LiFePO 4 are unknown or vary depending on synthetic methods. The multi-functional groups of fatty acids in the oils can orient properly to cope with the variable surface properties of LiFePO 4, which can lead to dense carbon coatings. The low price and low toxicity of kitchen oils are other advantages of the coating process. LiFePO 4 (D 50 = 121 nm)combined with the carbon coating enhances the rate capability. Capacities at the 2 C rate reach 150 mAh g -1 or higher. The charge retention values of 2.0 C/0.2 C are between 94.4 and 98.9%.

  10. Adsorption of doxorubicin on poly(methyl methacrylate)-chitosan-heparin-coated activated carbon beads.

    PubMed

    Miao, Jianjun; Zhang, Fuming; Takieddin, Majde; Mousa, Shaker; Linhardt, Robert J

    2012-03-06

    Extracorporeal filter cartridges, filled with an activated carbon bead (ACB) adsorbent, have been used for removal of overdosed cancer drugs from the blood. Coatings on adsorbent matrices, poly(methyl methacrylate) (PMMA)/activated carbon bead and PMMA/chitosan/heparin/ACB composites, were tested to improve their biocompatibility and blood compatibility. PMMA coating on ACBs was accomplished in a straightforward manner using a PMMA solution in ethyl acetate. A one-step hybrid coating of ACBs with PMMA-anticoagulant heparin required the use of acetone and water co-solvents. Multilayer coatings with three components, PMMA, chitosan, and heparin, involved three steps: PMMA was first coated on ACBs; chitosan was then coated on the PMMA-coated surface; and finally, heparin was covalently attached to the chitosan coating. Surface morphologies were studied by scanning electron microscopy. X-ray photoelectron spectroscopy confirmed the -SO(3)(-) group. Adsorption, of a chemotherapy drug (doxorubicin) from both water and phosphate-buffered saline, by the coated ACBs was examined. The adsorption isotherm curves were fitted using the Freundlich model. The current adsorption system might find potential applications in the removal of high-dose regional chemotherapy drugs while maintaining high efficiency, biocompatibility, and blood compatibility.

  11. Performance of Ultra Hard Carbon Wear Coatings on Microgears Fabricated by Liga

    SciTech Connect

    Ager III, J.W.; Brown, I.G.; Christenson, T.R.; Dugger, M.T.; Follstaedt, D.M.; Knapp, J.A.; Monteiro, O.R.

    1998-12-18

    Stiction and friction are of concern for the reliable, long-term application of Ni-alloy micromachines. We have found that the application of a 30-70 nm hard carbon coating produces a significant reduction in the friction coefficient and wear rate of electroformed Ni substrates in reciprocating sliding contact under simulated MEMS operating conditions. To evaluate the performance of coated components, a series of 70-pm-thick microgears ranging in diameter from 0.2 to 2.2 mm were fabricated from electroformed Ni via standard LIGA processes and fixtured on posts in preparation for the coating procedure. A pulsed vacuum- arc deposition process was used to deposit a carbon coating on the gears with the plasma incident at a shallow angle to the gears' top surface. A sample bias of -2 keV was used in order to produce a coating with relatively low stress and good adhesion while maintaining high hardness. This coating process is known to be somewhat comformal to the component surfaces. The coating uniformity, particularly in the high-aspect-ratio areas between the gear teeth, was evaluated with micro-Raman spectroscopy. It is shown that the coating can be applied uniformly on the top gear surface. Between the gear teeth the coating was the same thickness as on top of the gear down to a point 50 ~m below the top surface. Below that point (i.e. between 50 and 70 Lm), the coating thickness is somewhat thinner, but is still present. These results demonstrate that it is possible to a deposit hard carbon coating on microgears to reduce friction and wear in micromachines.

  12. New Method for Development of Carbon Coated Silica Phases for Liquid Chromatography Part I. Preparation of Carbon Phases

    PubMed Central

    Paek, Changyub; McCormick, Alon V.; Carr, Peter W.

    2011-01-01

    Owing to its combination of unique selectivity and mechanical strength, commercial carbon clad zirconia (C/ZrO2) has been widely used for many applications, including fast two-dimensional liquid chromatography (2DLC). However, the low surface area available (only 20 - 30 m2/g for commercial porous ZrO2) limits its retentivity. We have recently addressed this limitation by developing a carbon phase coated on the high surface area of HPLC grade alumina (C/Al2O3). This material provides higher retentivity and comparable selectivity, but its use is still limited by how few HPLC quality types of alumina particles (e.g., particle size, surface area, pore size) are available. In this work, we have developed useful carbon phases on silica particles, which are available in various particle sizes, pore sizes and forms of HPLC grade. To make the carbon phase on silica, we first treat the silica surface with a monolayer or less of metal cations that bind to deprotonated silanols to provide catalytic sites for carbon deposition. After Al (III) treatment, a carbon phase is formed on the silica surface by chemical vapor deposition at 700 °C using hexane as the carbon source. The amount of Al (III) on the surface was varied to assess its effect on carbon deposition, and the carbon loading was varied at different Al (III) levels to assess its effect on the chromatographic properties of the various carbon adsorbents. We observed that use of a concentration of Al (III) corresponding to a full monolayer leads to the most uniform carbon coating. A carbon coating sufficient to cover all the Al (III) sites, required about 4 – 5 monolayers in this work, provided the best chromatographic performance. The resulting carbon phases behave as reversed phases with reasonable efficiency (50,000 – 79,000 plates/meter) for non-aromatic test species. PMID:21295308

  13. Semiquantitative Performance and Mechanism Evaluation of Carbon Nanomaterials as Cathode Coatings for Microbial Fouling Reduction

    PubMed Central

    Zhang, Qiaoying; Nghiem, Joanne; Silverberg, Gregory J.

    2015-01-01

    In this study, we examine bacterial attachment and survival on a titanium (Ti) cathode coated with various carbon nanomaterials (CNM): pristine carbon nanotubes (CNT), oxidized carbon nanotubes (O-CNT), oxidized-annealed carbon nanotubes (OA-CNT), carbon black (CB), and reduced graphene oxide (rGO). The carbon nanomaterials were dispersed in an isopropyl alcohol-Nafion solution and were then used to dip-coat a Ti substrate. Pseudomonas fluorescens was selected as the representative bacterium for environmental biofouling. Experiments in the absence of an electric potential indicate that increased nanoscale surface roughness and decreased hydrophobicity of the CNM coating decreased bacterial adhesion. The loss of bacterial viability on the noncharged CNM coatings ranged from 22% for CB to 67% for OA-CNT and was dependent on the CNM dimensions and surface chemistry. For electrochemical experiments, the total density and percentage of inactivation of the adherent bacteria were analyzed semiquantitatively as functions of electrode potential, current density, and hydrogen peroxide generation. Electrode potential and hydrogen peroxide generation were the dominant factors with regard to short-term (3-h) bacterial attachment and inactivation, respectively. Extended-time electrochemical experiments (12 h) indicated that in all cases, the density of total deposited bacteria increased almost linearly with time and that the rate of bacterial adhesion was decreased 8- to 10-fold when an electric potential was applied. In summary, this study provides a fundamental rationale for the selection of CNM as cathode coatings and electric potential to reduce microbial fouling. PMID:25956770

  14. TEM Studies of Carbon Coated LiFePO4 after Charge DischargeCycling

    SciTech Connect

    Gabrisch, H.; Wilcox, J.; Doeff, M.

    2006-11-30

    Carbon coating has proven to be a successful approach toimprove the rate capability of LiFePO4 used in rechargeable Li-ionbatteries. Investigations of the microstructure of carbon coated LiFePO4after charge discharge cycling shows that the carbon surface layerremains intact over 100 cycles. We find micro cracks in the cycledmaterial that extend parallel to low indexed lattice planes. Ourobservations differ from observations made by other authors. However thedifferences between the orientations of crack surfaces in both studiescan be reconciled considering the location of weak bonds in the unit celland specimen geometry as well as elastic stress fields ofdislocation.

  15. Surface modification of polyester fabric with plasma pretreatment and carbon nanotube coating for antistatic property improvement

    NASA Astrophysics Data System (ADS)

    Wang, C. X.; Lv, J. C.; Ren, Y.; Zhi, T.; Chen, J. Y.; Zhou, Q. Q.; Lu, Z. Q.; Gao, D. W.; Jin, L. M.

    2015-12-01

    This study introduced a green method to prepare antistatic polyester (PET) fabrics by plasma pretreatment and single-walled carbon nanotube (SWCNT) coating. The influences of plasma conditions and SWCNT coating parameters on antistatic property of PET fabrics were investigated. PET fabrics were pretreated under various plasma conditions such as different treatment times, output powers and working gases, and then SWCNT coating on the plasma treated PET fabrics was carried out by coating-dry-cure using various coating parameters including different SWCNT concentrations, curing times and curing temperatures. PET fabrics were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and volume resistivity. SEM and XPS analysis of the plasma treated PET fabrics revealed the increase in surface roughness and oxygen/nitrogen containing groups on the PET fiber surface. SEM and XPS analysis of the plasma treated and SWCNT coated PET fabrics indicated the SWCNT coating on PET fiber surface. The plasma treated and SWCNT coated PET fabrics exhibited a good antistatic property, which increased and then decreased with the increasing plasma treatment time and output power. The antistatic property of the O2 plasma treated and SWCNT coated PET fabric was better and worse than that of N2 or Ar plasma treated and SWCNT coated PET fabric in the shorter treatment time and the longer treatment time, respectively. In addition, the antistatic property of the plasma treated and SWCNT coated PET fabrics also increased with the increasing SWCNT concentration, curing time and curing temperature in the range studied. Plasma conditions and SWCNT coating parameters had signally influence on the antistatic property of plasma treated and SWCNT coated PET fabrics. Therefore, adequate parameters should be carefully selected for the optimum antistatic property of the plasma treated and SWCNT coated PET fabrics.

  16. In situ formation of low friction ceramic coatings on carbon steel by plasma electrolytic oxidation in two types of electrolytes

    NASA Astrophysics Data System (ADS)

    Wang, Yunlong; Jiang, Zhaohua

    2009-04-01

    In situ formation of ceramic coatings on Q235 carbon steel was achieved by plasma electrolytic oxidation (PEO) in carbonate electrolyte and silicate electrolyte, respectively. The surface and cross-section morphology, phase and elemental composition of PEO coatings were examined by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). The bond strength of the coating was determined using a direct pull-off test. The hardness as well as tribological properties of the ceramic coating was primarily studied. The results indicated that the coating obtained in carbonate electrolyte was Fe 3O 4, while the coating achieved from silicate electrolyte was proved to be amorphous. Both kinds of coatings showed coarse and porous surface. The Fe 3O 4 coatings obtained in carbonate electrolyte showed a high bonding strength to the substrate up to 20 ± 2 MPa and the value was 15 ± 2 MPa for the amorphous coatings obtained in carbonate electrolyte. The micro hardness of the amorphous coating and the Fe 3O 4 coating was 1001 Hv and 1413 Hv, respectively, which was more than two and three times as that of the Q235 alloy substrate (415 Hv). The friction coefficient exhibited by amorphous coating and Fe 3O 4 coating was 0.13 and 0.11, respectively, both lower than the uncoated Q235 substrate which ranged from 0.17 to 0.35.

  17. Plasma-sprayed hydroxyapatite coating on carbon/carbon composite scaffolds for bone tissue engineering and related tests in vivo.

    PubMed

    Cao, Ning; Dong, Jianwen; Wang, Qiangxiu; Ma, Quansheng; Wang, Feng; Chen, Huaying; Xue, Chengqian; Li, Musen

    2010-03-01

    The bioactive hydroxyapatite (HA) coatings were successfully prepared on carbon/carbon composites (C/C) by means of sand-blasting pretreatment and plasma-spraying technology. X-ray diffraction was employed to analyze the phase constitute of the coatings. Meanwhile, the bond strength between the HA coatings and C/C substrates was determined via shear test. Experimental results show that the coatings constitute HA, CaO, and other amorphous phosphates. The post heat treatment could effectively increase crystallization and purity of the coatings. Through observation and analysis by electron microprobe and scanning electron microscopy, it is concluded that the bond strength of the plasma-sprayed HA coatings on C/C is mainly determined by the interface structure and can be further improved by the post heat treatment. Meanwhile, the implantation in vivo was carried out in hybrid goats. The histological observation revealed that the osteoplaque gradually grew on the surface of the HA coatings and the pure C/C surface was covered by the fibrous tissues. No inflammation symptoms were found in the bone tissue around the implants.

  18. Tribological properties, corrosion resistance and biocompatibility of magnetron sputtered titanium-amorphous carbon coatings

    NASA Astrophysics Data System (ADS)

    Dhandapani, Vishnu Shankar; Subbiah, Ramesh; Thangavel, Elangovan; Arumugam, Madhankumar; Park, Kwideok; Gasem, Zuhair M.; Veeraragavan, Veeravazhuthi; Kim, Dae-Eun

    2016-05-01

    Amorphous carbon incorporated with titanium (a-C:Ti) was coated on 316L stainless steel (SS) by magnetron sputtering technique to attain superior tribological properties, corrosion resistance and biocompatibility. The morphology, topography and functional groups of the nanostructured a-C:Ti coatings in various concentrations were analyzed using atomic force microscopy (AFM), Raman, X-Ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Raman and XPS analyses confirmed the increase in sp2 bonds with increasing titanium content in the a-C matrix. TEM analysis confirmed the composite nature of the coating and the presence of nanostructured TiC for Ti content of 2.33 at.%. This coating showed superior tribological properties compared to the other a-C:Ti coatings. Furthermore, electrochemical corrosion studies were performed against stimulated body fluid medium in which all the a-C:Ti coatings showed improved corrosion resistance than the pure a-C coating. Preosteoblasts proliferation and viability on the specimens were tested and the results showed that a-C:Ti coatings with relatively high Ti (3.77 at.%) content had better biocompatibility. Based on the results of this work, highly durable coatings with good biocompatibility could be achieved by incorporation of optimum amount of Ti in a-C coatings deposited on SS by magnetron sputtering technique.

  19. Preparation of cribriform sheet-like carbon-coated zinc oxide with improved electrochemical performance

    NASA Astrophysics Data System (ADS)

    Huang, Jianhang; Yang, Zhanhong; Xie, Xiaoe; Feng, Zhaobin; Zhang, Zheng

    2015-09-01

    Cribriform sheet-like carbon-coated ZnO are prepared using pyrrole as the carbon source. It is found that a sheet-like precursor will form when polymerizing pyrrole in the presence of ZnO particles. After the carbonization of precursor, cribriform sheet-like carbon-coated ZnO can be obtained. Morphology and structure analysis of as-prepared carbon-coated ZnO is conducted by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The carbon overlayer not only present a barrier layer on the surface of the ZnO particles, which keeps relative high discharge capacity by inhibiting the active materials in electrode from dissolving into electrolyte, but also modify the surface status of ZnO particles so as to obtain more uniform current distribution and improved conductivity. As a result, when evaluated as an anode material for Zn/Ni cell, carbon-coated ZnO exhibit a more stable cycle performance than bare ZnO electrode.

  20. Mechanical characterization of copper coated carbon nanotubes reinforced aluminum matrix composites

    SciTech Connect

    Maqbool, Adnan; Hussain, M. Asif; Khalid, F. Ahmad; Bakhsh, Nabi; Hussain, Ali; Kim, Myong Ho

    2013-12-15

    In this investigation, carbon nanotube (CNT) reinforced aluminum composites were prepared by the molecular-level mixing process using copper coated CNTs. The mixing of CNTs was accomplished by ultrasonic mixing and ball milling. Electroless Cu-coated CNTs were used to enhance the interfacial bonding between CNTs and aluminum. Scanning electron microscope analysis revealed the homogenous dispersion of Cu-coated CNTs in the composite samples compared with the uncoated CNTs. The samples were pressureless sintered under vacuum followed by hot rolling to promote the uniform microstructure and dispersion of CNTs. In 1.0 wt.% uncoated and Cu-coated CNT/Al composites, compared to pure Al, the microhardness increased by 44% and 103%, respectively. As compared to the pure Al, for 1.0 wt.% uncoated CNT/Al composite, increase in yield strength and ultimate tensile strength was estimated about 58% and 62%, respectively. However, in case of 1.0 wt.% Cu-coated CNT/Al composite, yield strength and ultimate tensile strength were increased significantly about 121% and 107%, respectively. - Graphical Abstract: Copper coated CNTs were synthesized by the electroless plating process. Optimizing the plating bath to (1:1) by wt CNTs with Cu, thickness of Cu-coated CNTs has been reduced to 100 nm. Cu-coated CNTs developed the stronger interfacial bonding with the Al matrix which resulted in the efficient transfer of load. Highlights: • Copper coated CNTs were synthesized by the electroless plating process. • Thickness of Cu-coated CNTs has been reduced to 100 nm by optimized plating bath. • In 1.0 wt.% Cu-coated CNT/Al composite, microhardness increased by 103%. • Cu-coated CNTs transfer load efficiently with stronger interfacial bonding. • In 1.0 wt.% Cu-coated CNT/Al composite, Y.S and UTS increased by 126% and 105%.

  1. Mesoporous hollow nanospheres consisting of carbon coated silica nanoparticles for robust lithium-ion battery anodes

    NASA Astrophysics Data System (ADS)

    An, Weili; Fu, Jijiang; Su, Jianjun; Wang, Lei; Peng, Xiang; Wu, Kai; Chen, Qiuyun; Bi, Yajun; Gao, Biao; Zhang, Xuming

    2017-03-01

    SiO2 as lithium ion batteries (LIBs) anode has drawn considerable attentions because of its low cost, high theoretical specific capacity and low discharge potentials but been limited by its low conductivity and electrochemical kinetics, resulting in obvious capacity decay and poor rate performance. Herein, we developed a simple approach to synthesize mesoporous hollow nanosphere (MHSiO2@C) assembled by conformal carbon coating tiny silica nanoparticles through chemical polymerization of dopamine inside the shell of MHSiO2. The continuous carbon can conformally coat on the surface of all primary SiO2 nanoparticles in the shell, which not only enhances the conductivity but also improves the structural stability of the MHSiO2. Compared to raw MHSiO2 and non-conformal carbon coated MHSiO2, the MHSiO2@C demonstrate a high reversible capacity of 440.7 mA h g-1 at a current density of 0.5 A g-1 after 500 cycles and excellent rate performance due to synergetic effect of special structure of MHSiO2 and carbon conformal coating on each silica nanoparticle. Such a special structure will be a promising platform for LIBs. Significantly, this paper offers a direct evidence to prove the advantage of conformal carbon coating and provides consequentially guide in improving the energy storage performance of low-conductivity oxide based electrode materials.

  2. Synthesis, characterization and electrical properties of carbon coated LiCoPO4 nanoparticles.

    PubMed

    Kumar, P Ramesh; Venkateswarlu, M; Misra, Manjusri; Mohanty, Amar K; Satyanayana, N

    2011-04-01

    Lithium cobalt phosphate (LiCoPO4) nanoparticles were synthesized using modified polyol process. Shape and size of LiCoPO4 nanoparticles were controlled by using poly (vinylpyrrolidone) (PVP) stabilizer. Coating of carbon over the LiCoPO4 nanoparticles was done using the resin coating process to enhance its conductivity. XRD and FTIR results respectively confirm the crystalline phase and structure of pure and carbon coated LiCoPO4 nanoparticles. SEM-EDX results confirm size and shape and also the presence of carbon over LiCoPO4 nanoparticles. Electrical conductivity of pure and carbon coated LiCoPO4 nanoparticles were evaluated by analyzing the measured impedance data using the win fit software. More than three orders of conductivity enhancement was observed in carbon coated LiCoPO4 nanoparticles when compared to pure ones. Further, transport properties like temperature dependence conductivity, AC conductivity, dielectric constant and electric modulus studies were made to find out the bulk and relaxation properties of LiCoPO4 nanoparticles.

  3. The Influence of Calcium Carbonate Grain Coatings on Contaminant Reactivity in Vadose Zone Sediments

    SciTech Connect

    Zachara, John M.; Chambers, Scott; Brown Jr., Gordon E.; Eggleston, Carrick M.

    2001-06-01

    Calcium carbonate (CaCO3) is widely distributed through the Hanford vadose zone as a minor phase. As a result of current and past geochemical processes, CaCO3 exists as grain coatings, intergrain fill, and distinct caliche layers in select locations. Calcium carbonate may also precipitate when high-level wastes react with naturally Ca- and Mg-saturated Hanford sediments. Calcium carbonate is a very reactive mineral phase. Sorption reactions on its surface may slow the migration of certain contaminants (Co, Sr), but its surface coatings on other mineral phases may diminish contaminant retardation (for example, Cr) by blocking surface reaction sites of the substrate. This project explores the behavior of calcium carbonate grain coatings, including how they form and dissolve, their reactivity toward key Hanford contaminants, their impact (as surface coatings) on the reactivity of other mineral substrates, and on their in-ground composition and minor element enrichment. The importance of CaCO3 as a contaminant sorbent will be defined in all of its different manifestations in Hanford sediments: dispersed minor lithic fragments, pedogenic carbonate coatings on gravel and stringers in silt, and nodules in clay and paleosols. Mass action models will be developed that allow understanding and prediction of the geochemical effects of CaCO3 on contaminant retardation in Hanford sediments.

  4. DLC coatings for UHMWPE: relationship between bacterial adherence and surface properties.

    PubMed

    Del Prado, G; Terriza, A; Ortiz-Pérez, A; Molina-Manso, D; Mahillo, I; Yubero, F; Puértolas, J A; Manrubia-Cobo, M; Gómez Barrena, E; Esteban, J

    2012-10-01

    Development of intrinsically antibacterial surfaces is of key importance in the context of prostheses used in orthopedic surgery. This work presents a thorough study of several plasma-based coatings that may be used with this functionality: diamond-like carbon (DLC), fluorine-doped DLC (F-DLC), and a high-fluorine-content-carbon-fluor polymer (CF(X)). The coatings were obtained by a radio-frequency plasma-assisted deposition on ultra high molecular weight polyethylene (UHMWPE) samples and physicochemical properties of the coated surfaces were correlated with their antibacterial performance against collection and clinical Staphylococcus aureus and Staphylococcus epidermidis strains. The fluorine content and the relative amount of C-C and C-F bonds were controlled by X-ray photoelectron spectroscopy, and hydrophobicity and surface tension by contact angle measurements. Surface roughness was studied by Atomic Force Microscopy. Additional nanoidentation studies were performed for DLC and F-DLC coatings. Unpaired t test and regression linear models evaluated the adherence of S. aureus and S. epidermidis on raw and coated UHMWPE samples. Comparing with UHMWPE, DLC/UHMWPE was the least adherent surface with independence of the bacterial species, finding significant reductions (p ≤ 0.001) for nine staphylococci strains. Bacterial adherence was also significantly reduced in F-DLC/ UHMWPE and CFx/UHMWPE for six strains.

  5. Characterization of microstructure and mechanical behavior of sputter deposited Ti-containing amorphous carbon coatings.

    SciTech Connect

    Feng, B.; Cao, D. M.; Meng, W. J.; Xu, J.; Tittsworth, R. C.; Rehn, L. E.; Baldo, P. M.; Doll, G. L.; Materials Science Division; Louisiana State Univ.; The Timken Company

    2001-12-03

    We report on the characterization of microstructure and mechanical properties of sputter deposited Ti-containing amorphous carbon (Ti-aC) coatings as a function of Ti composition. Ti-aC coatings have been deposited by unbalanced magnetron sputter deposition, in an industrial-scale four-target coating deposition system. The composition and microstructure of the Ti-aC coatings have been characterized in detail by combining the techniques of Rutherford backscattering spectrometry (RBS) and hydrogen elastic recoil detection (ERD), transmission electron microscopy (TEM), X-ray absorption near edge structure (XANES) spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. At Ti compositions <4at.%, Ti atoms dissolve in an amorphous carbon (a-C) matrix. The dissolution limit of Ti atoms in an a-C matrix is determined to be between 4 and 8 at.%. At Ti compositions >8 at.%, XANES and EXAFS data indicate that the average Ti atomic bonding environment in Ti-aC coatings resembles that in cubic B1-TiC, consistent with TEM observation of precipitation of TiC nanocrystallites in the a-C matrix. Beyond the Ti dissolution limit, the Ti-aC coatings are nanocomposites with nanocrystalline TiC clusters embedded in an a-C matrix. A large scale, quasi one-dimensional composition modulation in the Ti-aC coatings was observed due to the particular coating deposition geometry. Elastic stiffness and hardness of the Ti-aC coatings were measured by instrumented nanoindentation and found to vary systematically as a function of Ti composition. Unlubricated friction coefficient of Ti-aC coatings against WC-Co balls was found to increase as the Ti composition increases. As Ti composition increases, the overall mechanical behavior of the Ti-aC coatings becomes more TiC-like.

  6. Fabrication and characterization of DLC coated microdimples on hip prosthesis heads.

    PubMed

    Choudhury, Dipankar; Ay Ching, Hee; Mamat, Azuddin Bin; Cizek, Jan; Abu Osman, Noor Azuan; Vrbka, Martin; Hartl, Martin; Krupka, Ivan

    2015-07-01

    Diamond like carbon (DLC) is applied as a thin film onto substrates to obtain desired surface properties such as increased hardness and corrosion resistance, and decreased friction and wear rate. Microdimple is an advanced surface modification technique enhancing the tribological performance. In this study, DLC coated microdimples were fabricated on hip prosthesis heads and their mechanical, material and surface properties were characterized. An Electro discharge machining (EDM) oriented microdrilling was utilized to fabricate a defined microdimple array (diameter of 300 µm, depth of 70 µm, and pitch of 900 µm) on stainless steel (SS) hip prosthesis heads. The dimpled surfaces were then coated by hydrogenated amorphous carbon (a-C:H) and tetrahedral amorphous carbon (Ta-C) layers by using a magnetron sputtering technology. A preliminary tribology test was conducted on these fabricated surfaces against a ceramic ball in simulated hip joint conditions. It was found that the fabricated dimples were perpendicular to the spherical surfaces and no cutting-tools wear debris was detected inside the individual dimples. The a-C:H and Ta-C coatings increased the hardness at both the dimple edges and the nondimpled region. The tribology test showed a significant reduction in friction coefficient for coated surfaces regardless of microdimple arrays: the lowest friction coefficient was found for the a-C:H samples (µ = 0.084), followed by Ta-C (µ = 0.119), as compared to the SS surface (µ = 0.248).

  7. Performance characteristics of zinc-rich coatings applied to carbon steel

    NASA Technical Reports Server (NTRS)

    Paton, W. J.

    1973-01-01

    A program was conducted to evaluate the performance of topcoated and untopcoated zinc-rich coatings. Sacrificial coatings of this type are required for protecting carbon steel structures from the aggressive KSC sea coast environment. A total of 59 commercially available zinc-rich coatings and 47 topcoated materials were exposed for an 18-month period. Test panels were placed in special racks placed approximately 30.5 m (100 feet) above the high tide line at the KSC Corrosion Test Site. Laboratory tests to determine the temperature resistance, abrasion resistance, and adhesion of the untopcoated zinc-rich coatings were also performed. It has been concluded that: (1) The inorganic types of zinc-rich coatings are far superior to the organic types in the KSC environment. (2) Organic zinc-rich coatings applied at 0.1 - 0.15 mm (4-6 mils) film thickness provide better corrosion protection than when applied at the manufacturers' recommended nominal film thickness of .08 mm (3 mils). (3) Topcoats are not necessary, or even desirable, when used in conjunction with zinc-rich coatings in the KSC environment. (4) Some types of inorganic zinc-rich coatings require an extended outdoor weathering period in order to obtain adequate mechanical properties. and (5) A properly formulated inorganic zinc-rich coating is not affected by a 24-hour thermal exposure to 400 C (752 F).

  8. Pyrolytic deposition of nanostructured titanium carbide coatings on the surface of multiwalled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kremlev, K. V.; Ob"edkov, A. M.; Ketkov, S. Yu.; Kaverin, B. S.; Semenov, N. M.; Gusev, S. A.; Tatarskii, D. A.; Yunin, P. A.

    2016-05-01

    Nanostructured titanium carbide coatings have been deposited on the surface of multiwalled carbon nanotubes (MWCNTs) by the MOCVD method with bis(cyclopentadienyl)titanium dichloride precursor. The obtained TiC/MWCNT hybrid materials were characterized by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. It is established that a TiC coating deposits onto the MWCNT surface with the formation of a core-shell (MWSNT-TiC) type structure.

  9. Sealing of hard CrN and DLC coatings with atomic layer deposition.

    PubMed

    Härkönen, Emma; Kolev, Ivan; Díaz, Belén; Swiatowska, Jolanta; Maurice, Vincent; Seyeux, Antoine; Marcus, Philippe; Fenker, Martin; Toth, Lajos; Radnoczi, György; Vehkamäki, Marko; Ritala, Mikko

    2014-02-12

    Atomic layer deposition (ALD) is a thin film deposition technique that is based on alternating and saturating surface reactions of two or more gaseous precursors. The excellent conformality of ALD thin films can be exploited for sealing defects in coatings made by other techniques. Here the corrosion protection properties of hard CrN and diamond-like carbon (DLC) coatings on low alloy steel were improved by ALD sealing with 50 nm thick layers consisting of Al2O3 and Ta2O5 nanolaminates or mixtures. In cross sectional images the ALD layers were found to follow the surface morphology of the CrN coatings uniformly. Furthermore, ALD growth into the pinholes of the CrN coating was verified. In electrochemical measurements the ALD sealing was found to decrease the current density of the CrN coated steel by over 2 orders of magnitude. The neutral salt spray (NSS) durability was also improved: on the best samples the appearance of corrosion spots was delayed from 2 to 168 h. On DLC coatings the adhesion of the ALD sealing layers was weaker, but still clear improvement in NSS durability was achieved indicating sealing of the pinholes.

  10. Improvement in cell proliferation on silicone rubber by carbon nanotube coating.

    PubMed

    Matsuoka, Makoto; Akasaka, Tsukasa; Hashimoto, Takeshi; Totsuka, Yasunori; Watari, Fumio

    2009-01-01

    Silicone rubbers are widely used as tissue implants because of their flexibility and chemical stability. However, they have limited cellular adhesiveness and may cause problems in the long term. In this study, a coating of carbon nanotubes (CNTs) was applied to silicone rubber to improve its cellular adhesiveness. Scanning electron micrograph of this coating revealed that CNTs had formed a densely packed meshwork; the Ra values and protein adsorption capacity were enhanced. Although the contact angle did not change after coating, it decreased after immersion into a culture medium. After cultivation for 6 d, while Saos-2 cells were hardly observed on untreated silicone, the cells proliferated on CNT-coated silicone. Thus, CNT coating might be a simple and effective solution to problems associated with silicone implants.

  11. Characteristics of copper meshes coated with carbon nanotubes via electrophoretic deposition

    NASA Astrophysics Data System (ADS)

    Kim, Bu-Jong; Park, Jong-Seol; Hwang, Young-Jin; Park, Jin-Seok

    2016-09-01

    This study demonstrates the characteristics of a hybrid-type transparent electrode for touch screen panels, which was fabricated by coating carbon nanotubes (CNTs) via electrophoretic deposition (EPD) on copper (Cu)-meshes. The surface morphologies, visible-range transmittance and reflectance, and chromatic properties, such as yellowness and redness, of the fabricated CNTs-coated Cu mesh electrodes were characterized as functions of their dimensions (line-to-line spacing, line width, and electrode thickness) and compared with those of the Cu-mesh electrodes without coating of CNTs. The experimental results showed that the coating of CNTs substantially reduced the reflectance of the Cu-mesh electrodes and also improved their chromatic properties with their transmittance and sheet resistance only slightly changed, subsequently indicating that the CNTs-coated Cu-mesh electrodes possessed desirable characteristics for touch screen panels.

  12. Ordered mesoporous carbon/Nafion as a versatile and selective solid-phase microextraction coating.

    PubMed

    Zeng, Jingbin; Zhao, Cuiying; Chen, Jingjing; Subhan, Fazle; Luo, Liwen; Yu, Jianfeng; Cui, Bingwen; Xing, Wei; Chen, Xi; Yan, Zifeng

    2014-10-24

    In this study, ordered mesoporous carbon (OMC) with large surface area (1019m(2)g(-1)), uniform mesoporous structure (pore size distribution centering at 4.2nm) and large pore volume (1.46cm(3)g(-1)) was synthesized using 2D hexagonally mesoporous silica MSU-H as the hard template and sucrose as the carbon precursor. The as-synthesized OMC was immobilized onto a stainless steel wire using Nafion as a binder to prepare an OMC/Nafion solid-phase microextraction (SPME) coating. The extraction characteristics of the OMC/Nafion coating were extensively investigated using a wide range of analytes including non-polar (light petroleum and benzene homologues) and polar compounds (amines and phenols). The OMC/Nafion coating exhibited much better extraction efficiency towards all selected analytes than that of a multi-walled carbon nanotubes/Nafion coating with similar length and thickness, which is ascribed to its high surface area, well-ordered mesoporous structure and large pore volume. When the OMC/Nafion coating was used to extract a mixture containing various kinds of analytes, it possessed excellent extraction selectivity towards aromatic non-polar compounds. In addition, the feasibility of the OMC/Nafion coating for application in electrochemically enhanced SPME was demonstrated using protonated amines as model analytes.

  13. Electroless nickel-phosphorus coating on poly (ether ether ketone)/carbon nanotubes composite

    NASA Astrophysics Data System (ADS)

    Zhai, Tong; Di, Lizhi; Yang, De'an

    2014-05-01

    In order to improve electromagnetic shielding property of poly (ether ether ketone)/carbon nanotubes composite, a nickel-phosphorus coating was covered on the composite by electroless plating. The morphologies of the substrates and the coatings were characterized by SEM. XPS was performed to analyze the surface composition and chemical states before and after chemical etching. The results showed that lots of microscopic holes appeared and evenly distributed on the surface, and the concentration of hydrophilic groups on the surface increased after the composite was etched. Thermal shock test showed that the adhesive strength between the coating and the composite was good.

  14. Pyrolytic carbon-coated silicon/carbon nanofiber composite anodes for high-performance lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Chen, Yanli; Hu, Yi; Shao, Jianzhong; Shen, Zhen; Chen, Renzhong; Zhang, Xiangwu; He, Xia; Song, Yuanze; Xing, Xiuli

    2015-12-01

    Pyrolytic carbon-coated Si/C nanofibers (Si/C-CNFs) composites have been prepared through the sucrose coating and secondary thermal treatment of Si/CNFs composites produced via electrospinning and carbonization. This results in a structure in which Si nanoparticles are distributed along the fibers, with the fiber surface being coated with an amorphous carbon layer through pyrolysis of the sucrose. This carbon coating not only limits the volume expansion of the exposed Si nanoparticles, preventing their direct contact with the electrolyte, but also creates a connection between the fibers that is beneficial to Li+ ion transport, structural integrity, and electrochemical conductivity. Consequently, the Si/C-CNFs composite exhibits a more stable cycle performance, better rate performance, and higher conductivity than Si/CNFs alone. The optimal level of performance was attained with a 20:200 mass ratio of sucrose to deionized water, with a high retained capacity of 1215.2 mAh g-1 after 50 cycles, thus indicating that it is a suitable anode material for Li-ion batteries.

  15. Diamond Composite Films for Protective Coatings on Metals and Method of Formation

    NASA Technical Reports Server (NTRS)

    Ong, Tiong P. (Inventor); Shing, Yuh-Han (Inventor)

    1997-01-01

    Composite films consisting of diamond crystallites and hard amorphous films such as diamond-like carbon, titanium nitride, and titanium oxide are provided as protective coatings for metal substrates against extremely harsh environments. A composite layer having diamond crystallites and a hard amorphous film is affixed to a metal substrate via an interlayer including a bottom metal silicide film and a top silicon carbide film. The interlayer is formed either by depositing metal silicide and silicon carbide directly onto the metal substrate, or by first depositing an amorphous silicon film, then allowing top and bottom portions of the amorphous silicon to react during deposition of the diamond crystallites, to yield the desired interlayer structure.

  16. HYDROTHERMALLY SELF-ADVANCING HYBRID COATINGS FOR MITIGATING CORROSION OF CARBON STEEL.

    SciTech Connect

    SUGAMA, T.

    2006-11-22

    Hydrothermally self-advancing hybrid coatings were prepared by blending two starting materials, water-borne styrene acrylic latex (SAL) as the matrix and calcium aluminate cement (CAC) as the hydraulic filler, and then their usefulness was evaluated as the room temperature curable anti-corrosion coatings for carbon steel in CO{sub 2}-laden geothermal environments at 250 C. The following two major factors supported the self-improving mechanisms of the coating during its exposure in an autoclave: First was the formation of a high temperature stable polymer structure of Ca-complexed carboxylate groups containing SAL (Ca-CCG-SAL) due to hydrothermal reactions between SAL and CAC; second was the growth with continuing exposure time of crystalline calcite and boehmite phases coexisting with Ca-CCG-SAL. These two factors promoted the conversion of the porous microstructure in the non-autoclaved coating into a densified one after 7 days exposure. The densified microstructure not only considerably reduced the conductivity of corrosive ionic electrolytes through the coatings' layers, but also contributed to the excellent adherence of the coating to underlying steel' s surface that, in turn, retarded the cathodic oxygen reduction reaction at the corrosion site of steel. Such characteristics including the minimum uptake of corrosive electrolytes by the coating and the retardation of the cathodic corrosion reaction played an important role in inhibiting the corrosion of carbon steel in geothermal environments.

  17. Cr-Al coatings on low carbon steel prepared by a mechanical alloying technique

    NASA Astrophysics Data System (ADS)

    Hia, A. I. J.; Sudiro, T.; Aryanto, D.; Sebayang, K.

    2016-08-01

    Four different compositions of Cr and Al coatings as Cr10o, Cr87.5Al12.5, Cr5oAl5o, and Al100 have been prepared on the surface of low carbon steel by a mechanical alloying technique. The composition of each powder was milled for 2 hour in a stainless steel crucible with a ball to powder ratio of 10:1. Hereafter, the Cr-Al powder and substrate were mechanical alloyed in air for 1 hour. Heat treatment of coated sample were carried out at 800°C in a vacuum furnace. In order to characterize the phase composition and microstructure of the coating before and after heat treatment, XRD and SEM-EDX were used. The results show that Cr, Cr-Al or Al coatings were formed on the surface of low carbon steel. After heat treatment, new phases and interdiffusion zone were formed in the coating and at the coating/steel interface, depending on the coating composition.

  18. Characterization and nanomechanical properties of novel dental implant coatings containing copper decorated-carbon nanotubes.

    PubMed

    Sasani, N; Vahdati Khaki, J; Mojtaba Zebarjad, S

    2014-09-01

    Fluorapatite-titania coated Ti-based implants are promising for using in dental surgery for restoring teeth. One of the challenges in implantology is to achieve a bioactive coating with appropriate mechanical properties. In this research, simple sol-gel method was developed for synthesis of fluorapatite-titania-carbon nanotube decorated with antibacterial agent. Triethyl phosphate [PO4(C2H5)3], calcium nitrate [Ca(NO3)2] and ammonium fluoride (NH4F) were used as precursors under an ethanol-water based solution for fluorapatite (FA) production. Titanium isopropoxide and isopropanol were used as starting materials for making TiO2 sol-gels. Also, Copper acetate [Cu(C2H3O2)2·H2O] was used as precursor for decoration of multi walled carbon nanotubes (MWCNTs) with wet chemical method. The decorated MWCNTs (CNT(Cu)) were evaluated by transmission electron microscopy (TEM). The phase identification of the FA-TiO2-CNT(Cu) coating was carried out by XRD analysis. Morphology of coated samples was investigated by SEM observations. The surface elastic modulus and hardness of coatings were studied using nanoindentation technique. The results indicate that novel dental implant coating containing FA, TiO2 and copper decorated MWCNTs have proper morphological features. The results of nanoindentation test show that incorporation of CNT(Cu) in FA-TiO2 matrix can improve the nanomechanical properties of composite coating.

  19. Evaluating the Thermal Damage Resistance of Reduced Graphene Oxide/Carbon Nanotube Hybrid Coatings

    NASA Astrophysics Data System (ADS)

    David, Lamuel; Feldman, Ari; Mansfield, Elisabeth; Lehman, John; Singh, Gurpreet; National Institute of Standards and Technology Collaboration

    2014-03-01

    Carbon nanotubes and graphene are known to exhibit some exceptional thermal (K ~ 2000 to 4400 W.m-1K-1 at 300K) and optical properties. Here, we demonstrate preparation and testing of multiwalled carbon nanotubes and chemically modified graphene-composite spray coatings for use on thermal detectors for high-power lasers. The synthesized nanocomposite material was tested by preparing spray coatings on aluminum test coupons used as a representation of the thermal detector's surface. These coatings were then exposed to increasing laser powers and extended exposure times to quantify their damage threshold and optical absorbance. The graphene/carbon nanotube (prepared at varying mass% of graphene in CNTs) coatings demonstrated significantly higher damage threshold values at 2.5 kW laser power (10.6 μm wavelength) than carbon paint or MWCNTs alone. Electron microscopy and Raman spectroscopy of irradiated specimens showed that the composite coating endured high laser-power densities (up to 2 kW.cm-2) without significant visual damage. This research is based on work supported by the National Science Foundation (Chemical, Bioengineering, Environmental, and Transport Systems Division), under grant no. 1335862 to G. Singh.

  20. Energy distributions of field emitted electrons from carbide tips and tungsten tips with diamondlike carbon coatings

    SciTech Connect

    Yu, M.L. |; Kim, H.; Hussey, B.W.; Chang, T.H.; Mackie, W.A.

    1996-11-01

    We have measured the energy distributions of electrons field emitted from tungsten carbide, HfC{l_angle}100{r_angle}, and ZrC{l_angle}100{r_angle} tips, and tungsten field emitters with diamondlike carbon coatings. Multiple-peaked energy distributions were observed from instability induced emission sites on the carbide tips. Energy distributions of electrons field emitted from the diamondlike carbon coated tungsten tips were broader than those from metal tips. They also showed a shift towards lower energies with increases in the emission current. {copyright} {ital 1996 American Vacuum Society}

  1. Photocatalytic CO2 Reduction by Carbon-Coated Indium-Oxide Nanobelts.

    PubMed

    Pan, Yun-Xiang; You, Ya; Xin, Sen; Li, Yutao; Fu, Gengtao; Cui, Zhiming; Men, Yu-Long; Cao, Fei-Fei; Yu, Shu-Hong; Goodenough, John B

    2017-03-22

    Indium-oxide (In2O3) nanobelts coated by a 5-nm-thick carbon layer provide an enhanced photocatalytic reduction of CO2 to CO and CH4, yielding CO and CH4 evolution rates of 126.6 and 27.9 μmol h(-1), respectively, with water as reductant and Pt as co-catalyst. The carbon coat promotes the absorption of visible light, improves the separation of photoinduced electron-hole pairs, increases the chemisorption of CO2, makes more protons from water splitting participate in CO2 reduction, and thereby facilitates the photocatalytic reduction of CO2 to CO and CH4.

  2. Pretreatment process for forming a smooth surface diamond film on a carbon-coated substrate

    DOEpatents

    Feng, Z.; Brewer, M.; Brown, I.; Komvopoulos, K.

    1994-05-03

    A process is disclosed for the pretreatment of a carbon-coated substrate to provide a uniform high density of nucleation sites thereon for the subsequent deposition of a continuous diamond film without the application of a bias voltage to the substrate. The process comprises exposing the carbon-coated substrate, in a microwave plasma enhanced chemical vapor deposition system, to a mixture of hydrogen-methane gases, having a methane gas concentration of at least about 4% (as measured by partial pressure), while maintaining the substrate at a pressure of about 10 to about 30 Torr during the pretreatment. 6 figures.

  3. Pretreatment process for forming a smooth surface diamond film on a carbon-coated substrate

    DOEpatents

    Feng, Zhu; Brewer, Marilee; Brown, Ian; Komvopoulos, Kyriakos

    1994-01-01

    A process is disclosed for the pretreatment of a carbon-coated substrate to provide a uniform high density of nucleation sites thereon for the subsequent deposition of a continuous diamond film without the application of a bias voltage to the substrate. The process comprises exposing the carbon-coated substrate, in a microwave plasma enhanced chemical vapor deposition system, to a mixture of hydrogen-methane gases, having a methane gas concentration of at least about 4% (as measured by partial pressure), while maintaining the substrate at a pressure of about 10 to about 30 Torr during the pretreatment.

  4. Electroless Co-P-Carbon Nanotube composite coating to enhance magnetic properties of grain-oriented electrical steel

    NASA Astrophysics Data System (ADS)

    Goel, Vishu; Anderson, Philip; Hall, Jeremy; Robinson, Fiona; Bohm, Siva

    2016-06-01

    The effect of Co-P-CNT coating on the magnetic properties of grain oriented electrical steel was investigated. To analyse the coating, Raman spectroscopy, Superconducting QUantum Interference Device (SQUID), single strip testing, Scanning Electron Microscopy (SEM) and talysurf surface profilometry were performed. Raman spectra showed the D and G band which corroborates the presence of Multi-Walled Carbon Nanotubes (MWCNT) in the coating. The magnetic nature of the coating was confirmed by SQUID results. Power loss results show an improvement ranging 13-15% after coating with Co-P-CNT. The resistivity of the coating was measured to be 104 μΩ cm. Loss separation graphs were plotted before and after coating to study the improvement in power loss. It was found that the coating helps in reducing the hysteresis loss. The thickness of the coating was found to be 414±40 nm. The surface profilometry results showed that the surface roughness improved after coating the sample.

  5. Study on the oriented recrystallization of carbon-coated polyethylene oriented ultrathin films.

    PubMed

    Chang, Haibo; Guo, Qipeng; Shen, Deyan; Li, Lin; Qiu, Zhaobin; Wang, Feng; Yan, Shouke

    2010-10-21

    It is confirmed that a layer of vacuum-evaporated carbon on the surface of a preoriented ultrathin polymer film can lead to an oriented recrystallization of the polymer film. This has been attributed to a strong fixing effect of vacuum-evaporated carbon layer on the film surface of the polymer. To study the origin of the strong fixing effect of vacuum-evaporated carbon layer on the polymer films, the melting and recrystallization behaviors of the preoriented ultrathin PE film with a vacuum-evaporated carbon layer were studied by using atomic force microscopy, electron diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. We found that there exists some extent of chain orientation of carbon-coated polyethylene (PE) preoriented ultrathin film above its melting temperature. These oriented PE chain sequences act as nucleation sites and induce the oriented recrystallization of preoriented PE film from melt. Raman spectroscopy results suggest that new carbon-carbon bonds between the carbon layer and the oriented PE film are created during the process of vacuum carbon evaporation. As a result, some of the PE chain stems are fixed to the coated carbon substrate via covalent bond. Such a bonding has retarded the relaxation of the PE chains at the spot and, therefore, preserves the original orientation of the PE stems at high temperature, which in turn derives the recrystallization of the PE chains in an oriented structure.

  6. Multi-layer carbon-based coatings for field emission

    DOEpatents

    Sullivan, John P.; Friedmann, Thomas A.

    1998-01-01

    A multi-layer resistive carbon film field emitter device for cold cathode field emission applications. The multi-layered film of the present invention consists of at least two layers of a conductive carbon material, preferably amorphous-tetrahedrally coordinated carbon, where the resistivities of adjacent layers differ. For electron emission from the surface, the preferred structure can be a top layer having a lower resistivity than the bottom layer. For edge emitting structures, the preferred structure of the film can be a plurality of carbon layers, where adjacent layers have different resistivities. Through selection of deposition conditions, including the energy of the depositing carbon species, the presence or absence of certain elements such as H, N, inert gases or boron, carbon layers having desired resistivities can be produced.

  7. Multi-layer carbon-based coatings for field emission

    DOEpatents

    Sullivan, J.P.; Friedmann, T.A.

    1998-10-13

    A multi-layer resistive carbon film field emitter device for cold cathode field emission applications is disclosed. The multi-layered film of the present invention consists of at least two layers of a conductive carbon material, preferably amorphous-tetrahedrally coordinated carbon, where the resistivities of adjacent layers differ. For electron emission from the surface, the preferred structure can be a top layer having a lower resistivity than the bottom layer. For edge emitting structures, the preferred structure of the film can be a plurality of carbon layers, where adjacent layers have different resistivities. Through selection of deposition conditions, including the energy of the depositing carbon species, the presence or absence of certain elements such as H, N, inert gases or boron, carbon layers having desired resistivities can be produced. 8 figs.

  8. Synthesis of Carbon-Coated ZnO Composite and Varistor Properties Study

    NASA Astrophysics Data System (ADS)

    Sun, Wei-Jie; Liu, Jin-Ran; Yao, Da-Chuan; Chen, Yong; Wang, Mao-Hua

    2017-01-01

    In this article, monodisperse ZnO composite nanoparticles were successfully prepared by sol-gel mixed precursor method. Subsequently, carbon as the shell was homogeneously coated on the surface of the ZnO composite nanoparticles via a simple adsorption and calcination process. Microstructural studies of the as-obtained powders were carried out using the techniques of the x-ray powder diffraction, scanning electron microscopy, field emission scanning electron microscopy, transmission electron microscopy with energy dispersive x-ray spectroscopy, and Fourier transform infrared spectroscopy. The results show that the pink ZnO composite powders were fully coated by carbon. Based on the results, the effect of glucose content on the microstructure of the synthesized composites and the electrical properties of the ZnO varistors sintered in air at 1150°C for 2 h were also fully studied. As the amount of glucose increased, the thickness of carbon can be increased from 2.5 nm to 5 nm. In particular, the ZnO varistor fabricated with the appropriate thickness of the carbon coating (5 nm) leads to the superior electrical performance, with present high breakdown voltage (V b = 420 V/mm) and excellent nonlinear coefficient (α = 61.7), compared with the varistors obtained without carbon coating.

  9. Synthesis of Carbon-Coated ZnO Composite and Varistor Properties Study

    NASA Astrophysics Data System (ADS)

    Sun, Wei-Jie; Liu, Jin-Ran; Yao, Da-Chuan; Chen, Yong; Wang, Mao-Hua

    2017-03-01

    In this article, monodisperse ZnO composite nanoparticles were successfully prepared by sol-gel mixed precursor method. Subsequently, carbon as the shell was homogeneously coated on the surface of the ZnO composite nanoparticles via a simple adsorption and calcination process. Microstructural studies of the as-obtained powders were carried out using the techniques of the x-ray powder diffraction, scanning electron microscopy, field emission scanning electron microscopy, transmission electron microscopy with energy dispersive x-ray spectroscopy, and Fourier transform infrared spectroscopy. The results show that the pink ZnO composite powders were fully coated by carbon. Based on the results, the effect of glucose content on the microstructure of the synthesized composites and the electrical properties of the ZnO varistors sintered in air at 1150°C for 2 h were also fully studied. As the amount of glucose increased, the thickness of carbon can be increased from 2.5 nm to 5 nm. In particular, the ZnO varistor fabricated with the appropriate thickness of the carbon coating (5 nm) leads to the superior electrical performance, with present high breakdown voltage ( V b = 420 V/mm) and excellent nonlinear coefficient ( α = 61.7), compared with the varistors obtained without carbon coating.

  10. Durable, Transparent, and Hot Liquid Repelling Superamphiphobic Coatings from Polysiloxane-Modified Multiwalled Carbon Nanotubes.

    PubMed

    Zhang, Junping; Yu, Bo; Gao, Ziqian; Li, Bucheng; Zhao, Xia

    2017-01-17

    Although encouraging progress in the field of superamphiphobic coatings has been obtained, the superamphiphobic coatings with high durability, transparency, and repellency to hot liquids are very rare. Here, durable, transparent, and hot liquid-repelling superamphiphobic coatings were successfully prepared using polysiloxane-modified multiwalled carbon nanotubes (MWCNTs@POS) as the templates. The hydrolytic condensation of n-hexadecyltrimethoxysilane (HDTMS) and tetraethoxysilane on the surface of MWCNTs formed MWCNTs@POS, which are highly dispersible in toluene. The superamphiphobic coatings were prepared by spray-coating the homogeneous suspension of MWCNTs@POS in toluene onto glass slides, calcination in air to form the silica nanotubes (SNTs), and then modification with 1H,1H,2H,2H-perfluorodecyltrichlorosilane in dry toluene. The changes in the surface microstructure, surface chemical composition, and wettability were characterized by various techniques such as scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. It was found that the microstructures of the SNTs have great influences on superamphiphobicity and transparency of the coatings and can be regulated by the concentration of HDTMS and the diameter of MWCNTs. The SNTs with tunable wall thickness and diameter could be obtained using the method. The superamphiphobic coatings showed high contact angles and low sliding angles for various cool and hot liquids of different surface tensions. The superamphiphobic coatings also exhibited high transparency and comprehensive durability.

  11. Sol-Gel-Derived Hydroxyapatite-Carbon Nanotube/Titania Coatings on Titanium Substrates

    PubMed Central

    Ji, Xiaoli; Lou, Weiwei; Wang, Qi; Ma, Jianfeng; Xu, Haihong; Bai, Qing; Liu, Chuantong; Liu, Jinsong

    2012-01-01

    In this paper, hydroxyapatite-carbon nanotube/titania (HA-CNT/TiO2) double layer coatings were successfully developed on titanium (Ti) substrates intended for biomedical applications. A TiO2 coating was firstly developed by anodization to improve bonding between HA and Ti, and then the layer of HA and CNTs was coated on the surface by the sol-gel process to improve the biocompatibility and mechanical properties of Ti. The surfaces of double layer coatings were uniform and crack-free with a thickness of about 7 μm. The bonding strength of the HA-CNT/TiO2 coating was higher than that of the pure HA and HA-CNT coatings. Additionally, in vitro cell experiments showed that CNTs promoted the adhesion of preosteoblasts on the HA-CNT/TiO2 double layer coatings. These unique surfaces combined with the osteoconductive properties of HA exhibited the excellent mechanical properties of CNTs. Therefore, the developed HA-CNT/TiO2 coatings on Ti substrates might be a promising material for bone replacement. PMID:22606041

  12. Hydroxyapatite-anatase-carbon nanotube nanocomposite coatings fabricated by electrophoretic codeposition for biomedical applications.

    PubMed

    Zhang, Bokai; Kwok, Chi Tat

    2011-10-01

    In order to eliminate micro-cracks in the monolithic hydroxyapatite (HA) and composite hydroxyapatite/carbon nanotube (HA/CNT) coatings, novel HA/TiO(2)/CNT nanocomposite coatings on Ti6Al4V were attempted to fabricate by a single-step electrophoretic codeposition process for biomedical applications. The electrophoretically deposited layers with difference contents of HA, TiO(2) (anatase) and CNT nanoparticles were sintered at 800°C for densification with thickness of about 7-10 μm. A dense and crack-free coating was achieved with constituents of 85 wt% HA, 10 wt% TiO(2) and 5 wt% CNT. Open-circuit potential measurements and cyclic potentiodynamic polarization tests were used to investigate the electrochemical corrosion behavior of the coatings in vitro conditions (Hanks' solution at 37°C). The HA/TiO(2)/CNT coatings possess higher corrosion resistance than that of the Ti6Al4V substrate as reflected by nobler open circuit potential and lower corrosion current density. In addition, the surface hardness and adhesion strength of the HA/TiO(2)/CNT coatings are higher than that of the monolithic HA and HA/CNT coatings without compromising their apatite forming ability. The enhanced properties were attributed to the nanostructure of the coatings with the appropriate TiO(2) and CNT contents for eliminating micro-cracks and micro-pores.

  13. Sol-gel-derived hydroxyapatite-carbon nanotube/titania coatings on titanium substrates.

    PubMed

    Ji, Xiaoli; Lou, Weiwei; Wang, Qi; Ma, Jianfeng; Xu, Haihong; Bai, Qing; Liu, Chuantong; Liu, Jinsong

    2012-01-01

    In this paper, hydroxyapatite-carbon nanotube/titania (HA-CNT/TiO(2)) double layer coatings were successfully developed on titanium (Ti) substrates intended for biomedical applications. A TiO(2) coating was firstly developed by anodization to improve bonding between HA and Ti, and then the layer of HA and CNTs was coated on the surface by the sol-gel process to improve the biocompatibility and mechanical properties of Ti. The surfaces of double layer coatings were uniform and crack-free with a thickness of about 7 μm. The bonding strength of the HA-CNT/TiO(2) coating was higher than that of the pure HA and HA-CNT coatings. Additionally, in vitro cell experiments showed that CNTs promoted the adhesion of preosteoblasts on the HA-CNT/TiO(2) double layer coatings. These unique surfaces combined with the osteoconductive properties of HA exhibited the excellent mechanical properties of CNTs. Therefore, the developed HA-CNT/TiO(2) coatings on Ti substrates might be a promising material for bone replacement.

  14. Fabrication of carbon-coated silicon nanowires and their application in dye-sensitized solar cells.

    PubMed

    Kim, Junhee; Lim, Jeongmin; Kim, Minsoo; Lee, Hae-Seok; Jun, Yongseok; Kim, Donghwan

    2014-11-12

    We report the fabrication of silicon/carbon core/shell nanowire arrays using a two-step process, involving electroless metal deposition and chemical vapor deposition. In general, foreign shell materials that sheath core materials change the inherent characteristics of the core materials. The carbon coating functionalized the silicon nanowire arrays, which subsequently showed electrocatalytic activities for the reduction of iodide/triiodide. This was verified by cyclic voltammetry and electrochemical impedance spectroscopy. We employed the carbon-coated silicon nanowire arrays in dye-sensitized solar cells as counter electrodes. We optimized the carbon shells to maximize the photovoltaic performance of the resulting devices, and subsequently, a peak power conversion efficiency of 9.22% was achieved.

  15. Flexible supercapacitor based on MnO2 coated laser carbonized electrodes

    NASA Astrophysics Data System (ADS)

    Rahimi, Rahim; Ochoa, Manuel; Yu, Wuyang; Ziaie, Babak

    2015-12-01

    This paper presents a facile, low-cost approach for fabrication of flexible hybrid carbon/ MnO2 pseudo-capacitors. The highly porous carbon electrodes of the supercapacitor are fabricated by laser pyrolysis of polyimide-laminated copper sheet and subsequently coated with a uniform thin layer of MnO2. The porous laser carbonized polyimide provides a high effective surface area for the MnO2 coating, resulting in an increase of 55% in the electrochemical performance of the supercapacitor. The fabricated device exhibits a specific capacitance of 7.1mFcm-2 at a scan rate of 40mVs-1. Moreover, the copper backing film provides a proper electrical contact to the high surface area carbon/ MnO2 composite for stability under mechanical deformation and low internal resistance.

  16. Barrier properties to surrogates of hydrogenated carbon nano-films deposited on PET by plasma-enhanced chemical vapour deposition.

    PubMed

    Oliveira, Éder C; Echegoyen, Yolanda; Nerin, Cristina; Cruz, Sandra A

    2014-01-01

    Poly(ethylene terephthalate) resin was contaminated with a series of surrogates using a US Food and Drug Administration protocol. The contaminated samples were coated with two different kinds of hydrogenated amorphous carbon thin films (a-C:H): one with diamond-like hydrogenated amorphous carbon and another with polymer-like hydrogenated carbon (PLCH) phases. To evaluate the barrier properties of the a-C:H films, migration assays were performed using food simulants. After the tests, analysis by gas chromatography with different detectors was carried out. The appearance of the films before and after the migration experiments was studied by field emission scanning electron microscopy. The results showed that a-C:H films have good barrier properties for most of the evaluated compounds, mainly when they are deposited as PLCH phase.

  17. Facile preparation of mesoporous carbon-silica-coated graphene for the selective enrichment of endogenous peptides.

    PubMed

    Zhang, Quanqing; Zhang, Qinghe; Xiong, Zhichao; Wan, Hao; Chen, Xiaoting; Li, Hongmei; Zou, Hanfa

    2016-01-01

    A sandwich-like composite composed of ordered mesoporous carbon-silica shell-coated graphene (denoted as graphene@mSiO2-C) was prepared by an in-situ carbonation strategy. A mesoporous silica shell was synthesized by a sol-gel method, and cetyltrimethyl ammonium bromide inside the mesopores were in-situ carbonized as a carbon source to obtain a carbon-silica shell. The resulting mesoporous carbon-silica material with a sandwich structure possesses a high surface area (600 m(2) g(-1)), large pore volume (0.587 cm(3) g(-1)), highly ordered mesoporous pore (3 nm), and high carbon content (30%). This material shows not only high hydrophobicity of graphene and mesoporous carbon but also a hydrophilic silica framework that ensures excellent dispersibility in aqueous solution. The material can capture many more peptides from bovine serum albumin tryptic digests than mesoporous silica shell-coated graphene, demonstrating great enrichment efficiency for peptides. Furthermore, the prepared composite was applied to the enrichment of low-abundance endogenous peptides in human serum. Based on Matrix-Assisted Laser Desorption/ Ionization Time of Flight Mass Spectrometry identification, the graphene@mSiO2-C could efficiently size-exclude proteins and enriches the low-abundant peptides on the graphene and mesoporous carbon. And based on the LC-MS/MS results, 892 endogenous peptides were obtained by graphene@mSiO2-C, hinting at its great potential in peptides analysis.

  18. Coatings.

    ERIC Educational Resources Information Center

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  19. A general protocol to coat titania shell on carbon-based composite cores using carbon as coupling agent

    SciTech Connect

    Zheng Rongbo; Meng Xianwei; Tang Fangqiong

    2009-05-15

    We present herein a general protocol to coat titania shell on carbon-based composite cores via the hydrolysis of titanium tetrabutoxide in a mixed solvent with the catalysis of ammonia. As coupling agent, their carbonaceous component can adsorb counter-charged NH{sub 4}{sup +}, and then the negatively charged ident toTiO{sup -} species are adsorbed via electrostatic interaction to form TiO{sub 2} shell. Various carbon-based cores with different functional components, such as Ag/C core/shell spheres, Ag/C nanocables, as well as magnetic (C-Fe{sub 3}O{sub 4}) hollow spheres can be coated with titania shell to form corresponding core/shell composites. Their optical or magnetic property is also investigated. Finally, anatase-phase titania shell with rough surface can be generated via hydrothermal treatment of aforementioned titania coated composites, which can further introduce the properties of anatase-phase titania to the composites. - Graphical abstract: A general protocol was developed to coat titania shell on carbon-based composite cores based on the carbonaceous surface. Typically, Ag/C/TiO{sub 2} core/shell spheres were formed via this method.

  20. Microwave absorption properties of FeCo-coated carbon fibers with varying morphologies

    NASA Astrophysics Data System (ADS)

    Wan, Yizao; Xiao, Jian; Li, Chunzhi; Xiong, Guangyao; Guo, Ruisong; Li, Lili; Han, Ming; Luo, Honglin

    2016-02-01

    Hybridizing carbon materials with magnetic metals and oxides has attracted much attention for enhanced microwave absorption. In this study, a magnetic Fe-Co alloy was coated on the surface of carbon fibers (FeCo@CFs) by electrodeposition. For the first time, different Fe-Co coating morphologies (thin plate, irregular particle, and pyramid) were obtained by adjusting the plating temperature. The morphology, structure, magnetic properties, and complex permittivity and permeability of the FeCo@CFs were determined as a function of plating temperature. Results show that the FeCo@CFs with different coating morphologies exhibit different magnetic properties and complex permittivity. The FeCo@CFs with plate-like morphology demonstrate the best absorption performance. It has been shown that the absorption of FeCo@CFs can be controlled by adjusting the morphology of Fe-Co coating, which provides a new and effective way to endow Fe-Co-coated carbon fibers with good microwave absorption properties.

  1. Computational Evaluation of Amorphous Carbon Coating for Durable Silicon Anodes for Lithium-Ion Batteries

    PubMed Central

    Hwang, Jeongwoon; Ihm, Jisoon; Lee, Kwang-Ryeol; Kim, Seungchul

    2015-01-01

    We investigate the structural, mechanical, and electronic properties of graphite-like amorphous carbon coating on bulky silicon to examine whether it can improve the durability of the silicon anodes of lithium-ion batteries using molecular dynamics simulations and ab-initio electronic structure calculations. Structural models of carbon coating are constructed using molecular dynamics simulations of atomic carbon deposition with low incident energies (1–16 eV). As the incident energy decreases, the ratio of sp2 carbons increases, that of sp3 decreases, and the carbon films become more porous. The films prepared with very low incident energy contain lithium-ion conducting channels. Also, those films are electrically conductive to supplement the poor conductivity of silicon and can restore their structure after large deformation to accommodate the volume change during the operations. As a result of this study, we suggest that graphite-like porous carbon coating on silicon will extend the lifetime of the silicon anodes of lithium-ion batteries.

  2. Optimization of carbon coatings on LiFePO 4

    NASA Astrophysics Data System (ADS)

    Doeff, Marca M.; Wilcox, James D.; Kostecki, Robert; Lau, Grace

    The electrochemical performance of LiFePO 4 in lithium cells is strongly dependent on the structure (disordered/graphene or D/G ratio) of the in situ carbon produced during synthesis from carbon-containing precursors. Addition of pyromellitic acid (PA) prior to final calcination results in lower D/G ratios, yielding a higher-rate material. Further, improvements in electrochemical performance are realized when graphitization catalysts such as ferrocene are also added during LiFePO 4 preparation, although overall carbon content is still less than 2 wt.%.

  3. Optimization of Carbon Coatings on LiFePO4

    SciTech Connect

    Doeff, Marca M.; Wilcox, James D.; Kostecki, Robert; Lau, Grace

    2005-07-14

    The electrochemical performance of LiFePO{sub 4} in lithium cells is strongly dependent on the structure (disordered/graphene or D/G ratio) of the in situ carbon produced during synthesis from carbon-containing precursors. Addition of pyromellitic acid (PA) prior to final calcination results in lower D/G ratios, yielding a higher-rate material. Further, improvements in electrochemical performance are realized when graphitization catalysts such as ferrocene are also added during LiFePO{sub 4} preparation, although overall carbon content is still less than 2 wt.%.

  4. Carbon coated face-centered cubic Ru-C nanoalloys.

    PubMed

    Zhao, Zhisheng; Meng, Chuanmin; Li, Peifang; Zhu, Wenjun; Wang, Qianqian; Ma, Yanming; Shen, Guoyin; Bai, Ligang; He, Hongliang; He, Duanwei; Yu, Dongli; He, Julong; Xu, Bo; Tian, Yongjun

    2014-09-07

    Carbon-encapsulated ruthenium-carbon (Ru-C) nanoalloys were synthesized by dynamic shocks. The Ru-C alloy shows a new fcc structure different from the original hcp structure of metal Ru. This fcc phase is assigned to a Ru32C4 solid solution with a lattice parameter of 3.868(2) Å and a bulk modulus KT0 of 272(12) GPa. The small amount of carbon in the solid solution enhances the thermodynamic and chemical stabilities with respect to pure Ru, as well as induces changes in the electronic properties, which have direct applications in improving the material's catalytic activity and selectivity.

  5. Industrially scaled pulsed laser deposition based coating techniques for the realization of hemocompatible surfaces for blood contact applications

    NASA Astrophysics Data System (ADS)

    Lackner, Juergen M.; Waldhauser, Wolfgang; Major, Roman; Major, Boguslaw; Czarnowska, Elzbieta; Bruckert, Franz

    2008-05-01

    Non-thrombogenic blood contacting surfaces and appropriate blood flow characteristics are essential for clinical application. State-of-the-art coatings are based on heparin and struggle with the problem of bleeding. Thus, there is increasing demand for developing new coating materials for improved human body acceptance. Materials deposited by vacuum coating techniques would be an excellent alternative if the coating temperatures can be kept low due to the applied substrate materials of low temperature resistance (mostly polymers). Under these circumstances, adequate film structure and high adhesion can be reached by the Pulsed Laser Deposition at room temperature (RT-PLD), which was developed to an industrial-scaled process at Laser Center Leoben. This process was applied to deposit Ti, TiN, TiCN and diamond-like carbon (DLC) on polyurethane, titanium and silicon substrates to study the biological interactions to blood cells and the kinetic mechanism of eukaryote cell attachment. Besides high biological acceptance, distinct differences for the critical delamination shear stress were found for the coatings, indicating higher adhesion at higher carbon contents.

  6. Investigation of WC-Co Electrospark Coatings with Various Carbon Contents

    NASA Astrophysics Data System (ADS)

    Burkov, A. A.; Pyachin, S. A.

    2014-06-01

    Electrospark deposition was employed to clad WC-10%Co, W/C1.6 -10%Co, and W/C0.5 -10%Co hard alloys on steel 1035, and the tribological properties of the coatings obtained were examined. The influence of the W/C ratio in the electrode materials on the decarburization of tungsten carbide was studied. It is shown that the degree of tungsten carbide degradation can be reduced by increasing the concentration of carbon in the WC-Co electrode materials, and also that the WC decarburization reaction is reversible on annealing. Coatings deposited using new electrode materials with an excess of carbon (W/C0.5) and/or tungsten (W/C1.6) have increased microhardness and improved frictional characteristics compared with the conventional coating.

  7. Coating geometry of Ag, Ti, Co, Ni, and Al nanoparticles on carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Barberio, M.; Stranges, F.; Xu, F.

    2015-04-01

    We present a morphology study on laser ablation produced metal nanoparticles (NPs) deposited on carbon nanotube (CNT) substrates. We analyzed the coating geometry and topography by processing AFM and SEM images. Our results show that Ag NPs aggregate together to form large agglomerates, that Ti NPs are well dispersed on the substrate surface forming a quasi-continuous layer, and that Co, Ni, and Al NPs coat quite uniformly CNTs and locally grow in a layer like fashion. We interpret the coating and clustering geometries in terms of cohesion, surface, and interfacial energies and diffusion barriers. Fractal analysis of composites morphology suggests the formation of structures with a smoother topography relative to pure carbon nanotubes for reactive metal nanoparticles.

  8. Relationship between carbon isotope composition and crystal morphology of coated and polycrystalline diamonds

    NASA Astrophysics Data System (ADS)

    Janson, G. F.; Muehlenbachs, K.; Stachel, T.

    2009-12-01

    The carbon isotope composition of diamond coats from Diavik Mine, Canada was measured by secondary ion mass spectrometry (SIMS). In most cases, carbon isotope ratio increases outwards from approximately -8.5 to approximately -6.5‰. Although it has not been widely noted in the literature due to sparse data coverage, this trend is consistent with measurements by other researchers at other sampling localities and therefore represents a unique insight into fluid evolution during the formation of diamond coat. We model the outwards increase in carbon isotope ratio by Rayleigh fractionation during growth of diamond coat in a closed system from an oxidized, carbon supersaturated fluid with a mantle-like carbon isotope signature. The carbon may have been exsolved as a volatile-rich fluid from upwelling kimberlite magma at depths greater than 120 km. The fluid either encountered preexisting diamond ‘seed’ crystals which served as nuclei for the coats or, in the absence of such seeds, precipitated opaque cuboid crystals. Reduction of oxidized carbon to diamond would be driven by the reduced character of the depleted lithosphere (Haggerty and Tompkins, 1983). Several polycrystalline diamonds were also studied by SIMS. These are homogeneous with respect to δ13C and therefore show no isotopic evidence of fluid evolution during their growth. The degree of supersaturation of a fluid commonly determines the crystal habit of minerals precipitated from the fluid. In the case of diamonds, dendritic coat is interpreted as a product of conditions intermediate between the low degree carbon supersaturation that produces polyhedral and hopper morphologies, and the very high supersaturation responsible for the growth of polycrystalline diamond. During closed system growth, precipitation of diamond depletes the fluid reservoir of carbon, resulting in isotopic profiles consistent with Rayleigh fractionation. This depletion necessarily reduces the chemical potential between fluid and

  9. Livestock air treatment using PVA-coated powdered activated carbon biofilter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficacy of polyvinyl alcohol (PVA) biofilters was studied using bench-scale biofilters and air from aerobically-treated swine manure. The PVA-coated powdered activated carbon particles showed excellent properties as a biofiltration medium: water holding capacity of 1.39 g H2O/g-dry PVA; wet por...

  10. Livestock Air Treatment Using PVA-Coated Powdered Activated Carbon Biofilter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ideal biofilter media provide surface for attachment of microorganisms responsible for removing air-born contaminants while facilitating passage of air. This study evaluated the efficacy of polyvinyl alcohol (PVA)-coated powdered activated carbon particles as a biofiltration medium. This material e...

  11. Redirected charge transport arising from diazonium grafting of carbon coated LiFePO4.

    PubMed

    Madec, L; Seid, K A; Badot, J-C; Humbert, B; Moreau, P; Dubrunfaut, O; Lestriez, B; Guyomard, D; Gaubicher, J

    2014-11-07

    The morphological and the electrical properties of carbon coated LiFePO4 (LFPC) active material functionalized by 4-ethynylbenzene tetrafluoroboratediazonium salt were investigated. For this purpose, FTIR, Raman, XPS, High Resolution Transmission Electron Microscopy (HRTEM) and Broadband Dielectric Spectroscopy (BDS) were considered. Electronic conductivities of LFPC samples at room temperature were found to decrease in a large frequency range upon simple immersion in polar solvents and to decrease further upon functionalization. Due to their high dipole moment, strongly physisorbed molecules detected by XPS likely add barriers to electron hopping. Significant alteration of the carbon coating conductivity was only observed, however, upon functionalization. This effect is most presumably associated with an increase in the sp(3) content determined by Raman spectroscopy, which is a strong indication of the formation of a covalent bond between the organic layer and the carbon coating. In this case, the electron flux appears to be redirected and relayed by short-range (intra chain) and long-range (inter chain) electron transport through molecular oligomers anchored at the LFPC surface. The latter are controlled by tunnelling and slightly activated hopping, which enable higher conductivity at low temperature (T < 250 K). Alteration of the electron transport within the carbon coating also allows detection of a relaxation phenomenon that corresponds to small polaron hopping in bulk LiFePO4. XPS and HRTEM images allow a clear correlation of these findings with the island type oligomeric structure of grafted molecules.

  12. Electrochemical properties of carbon-coated Si/B composite anode for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Kim, Hyung Sun; Chung, Kyung Yoon; Cho, Byung Won

    Carbon-coated Si and Si/B composite powders prepared by hydrocarbon gas (argon + 10 mol% propylene) pyrolysis were investigated as the anodes for lithium-ion batteries. Carbon-coated silicon anode demonstrated the first discharge and charge capacity as 1568 mAh g -1 and 1242 mAh g -1, respectively, with good capacity retention for 10 cycles. The capacity fading rate of carbon-coated Si/B composite anode decreased as the amounts of boron increased. In addition, the cycle life of carbon-coated Si/B/graphite composite anode has been significantly improved by using sodium carboxymethyl cellulose (NaCMC) and styrene butadiene rubber (SBR)/NaCMC mixture binders compared to the poly(vinylidene fluoride, PVdF) binder. A reversible capacity of about 550 mAh g -1 has been achieved at 0.05 mAm g -1 rate and its capacity could be maintained up to 450 mAh g -1 at high rate of 0.2 mAm g -1 even after 30 cycles. The improvement of the cycling performance is attributed to the lower interfacial resistance due to good electric contact between silicon particles and copper substrate.

  13. Micro-oxidation treatment to improve bonding strength of Sr and Na co-substituted hydroxyapatite coatings for carbon/carbon composites

    NASA Astrophysics Data System (ADS)

    Zhang, Leilei; Li, Hejun; Li, Kezhi; Zhang, Yulei; Liu, Shoujie; Guo, Qian; Li, Shaoxian

    2016-08-01

    To improve the bonding strength of Sr and Na co-substituted hydroxyapatite (SNH) coatings for carbon/carbon composites, carbon/carbon composites are surface modified by micro-oxidation treatment. The micro-oxidation treatment could generate large number of pores containing oxygenic functional groups on the surface of carbon/carbon composites. SNH is nucleated on the inwall of the pores and form a flaky shape coating with 10-50 nm in thickness and 200-900 nm in width. The bonding strength between SNH coating and carbon/carbon composites increases from 4.27 ± 0.26 MPa to 10.57 ± 0.38 MPa after the micro-oxidation treatment. The promotion of bonding strength is mainly attributed to the pinning effect caused by the pores and chemical bonding generated by the oxygenic functional groups.

  14. Oleic acid-grafted chitosan/graphene oxide composite coating for corrosion protection of carbon steel.

    PubMed

    Fayyad, Eman M; Sadasivuni, Kishor Kumar; Ponnamma, Deepalekshmi; Al-Maadeed, Mariam Al Ali

    2016-10-20

    An anticorrosion coating film based on the formation of nanocomposite coating is reported in this study. The composite consisted of chitosan (green matrix), oleic acid, and graphene oxide (nano filler). The nanocomposite coating was arranged on the surface of carbon steel, and the corrosion resistance was monitored using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP). Compared to the pure chitosan (CS) coating, the corrosion resistance of oleic acid-modified chitosan/graphene oxide film (CS/GO-OA) is increased by 100 folds. Since the well-dispersed smart grafted nanolayers delayed the penetration rate of corrosive species and thus maintained long term anticorrosive stability which is correlated with hydrophobicity and permeability.

  15. Optimal ferromagnetically-coated carbon nanotube tips for ultra-high resolution magnetic force microscopy.

    PubMed

    Lisunova, Y; Heidler, J; Levkivskyi, I; Gaponenko, I; Weber, A; Caillier, Ch; Heyderman, L J; Kläui, M; Paruch, P

    2013-03-15

    Using single-walled carbon nanotubes homogeneously coated with ferromagnetic metal as ultra-high resolution magnetic force microscopy probes, we investigate the key image formation parameters and their dependence on coating thickness. The crucial step of introducing molecular beam epitaxy for deposition of the magnetic coating allows highly controlled fabrication of tips with small magnetic volume, while retaining high magnetic anisotropy and prolonged lifetime characteristics. Calculating the interaction between the tips and a magnetic sample, including hitherto neglected thermal noise effects, we show that optimal imaging is achieved for a finite, intermediate-thickness magnetic coating, in excellent agreement with experimental observations. With such optimal tips, we demonstrate outstanding resolution, revealing sub-10 nm domains in hard magnetic samples, and non-perturbative imaging of nanoscale spin structures in soft magnetic materials, all at ambient conditions with no special vacuum, temperature or humidity controls.

  16. Synthesis and Photocatalytic Activity of Anatase TiO2 Nanoparticles-coated Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Xie, Yi; Heo, Sung Hwan; Yoo, Seung Hwa; Ali, Ghafar; Cho, Sung Oh

    2010-03-01

    A simple and straightforward approach to prepare TiO2-coated carbon nanotubes (CNTs) is presented. Anatase TiO2 nanoparticles (NPs) with the average size ~8 nm were coated on CNTs from peroxo titanic acid (PTA) precursor even at low temperature of 100 °C. We demonstrate the effects of CNTs/TiO2 molar ratio on the adsorption capability and photocatalytic efficiency under UV-visible irradiation. The samples showed not only good optical absorption in visible range, but also great adsorption capacity for methyl orange (MO) dye molecules. These properties facilitated the great enhancement of photocatalytic activity of TiO2 NPs-coated CNTs photocatalysts. The TiO2 NPs-coated CNTs exhibited 2.45 times higher photocatalytic activity for MO degradation than that of pure TiO2.

  17. Single-walled carbon nanotubes coated with ZnO by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Pal, Partha P.; Gilshteyn, Evgenia; Jiang, Hua; Timmermans, Marina; Kaskela, Antti; Tolochko, Oleg V.; Kurochkin, Alexey V.; Karppinen, Maarit; Nisula, Mikko; Kauppinen, Esko I.; Nasibulin, Albert G.

    2016-12-01

    The possibility of ZnO deposition on the surface of single-walled carbon nanotubes (SWCNTs) with the help of an atomic layer deposition (ALD) technique was successfully demonstrated. The utilization of pristine SWCNTs as a support resulted in a non-uniform deposition of ZnO in the form of nanoparticles. To achieve uniform ZnO coating, the SWCNTs first needed to be functionalized by treating the samples in a controlled ozone atmosphere. The uniformly ZnO coated SWCNTs were used to fabricate UV sensing devices. An UV irradiation of the ZnO coated samples turned them from hydrophobic to hydrophilic behaviour. Furthermore, thin films of the ZnO coated SWCNTs allowed us switch p-type field effect transistors made of pristine SWCNTs to have ambipolar characteristics.

  18. Design and synthesis of superhydrophobic carbon nanofiber composite coatings for terahertz frequency shielding and attenuation

    NASA Astrophysics Data System (ADS)

    Das, Arindam; Megaridis, Constantine M.; Liu, Lei; Wang, Tao; Biswas, Abhijit

    2011-04-01

    We report design and synthesis of polymer-based large-area superhydrophobic carbon nanofiber (CNF) composite coatings for tunable electromagnetic interference shielding and attenuation in the terahertz (THz) frequency regime. Such coatings with different CNF/polymer weight ratios are characterized by a frequency domain THz spectroscopy system. A maximum THz shielding effectiveness of ˜32 dB was measured in the examined frequency range of 570-630 GHz. Coating attenuation level varied with CNF loading. Two-dimensional distributions of power attenuation at 600 GHz showed good spatial uniformity. The present composite coatings, in addition to their self-cleaning property, have high potential for advanced technology high-frequency applications.

  19. Tests Of Materials For Repair Coating Of Carbon Steel

    NASA Technical Reports Server (NTRS)

    Macdowell, Louis G., III

    1995-01-01

    Report describes tests of paints (primers and topcoats) for use in recoating rusted carbon steel for protection against further corrosion. Paints selected for evaluation all designated by manufacturers as suitable for application over tightly adhering rust.

  20. Effect of tetrahedral amorphous carbon coating on the resistivity and wear of single-walled carbon nanotube network

    NASA Astrophysics Data System (ADS)

    Iyer, Ajai; Kaskela, Antti; Novikov, Serguei; Etula, Jarkko; Liu, Xuwen; Kauppinen, Esko I.; Koskinen, Jari

    2016-05-01

    Single walled carbon nanotube networks (SWCNTNs) were coated by tetrahedral amorphous carbon (ta-C) to improve the mechanical wear properties of the composite film. The ta-C deposition was performed by using pulsed filtered cathodic vacuum arc method resulting in the generation of C+ ions in the energy range of 40-60 eV which coalesce to form a ta-C film. The primary disadvantage of this process is a significant increase in the electrical resistance of the SWCNTN post coating. The increase in the SWCNTN resistance is attributed primarily to the intrinsic stress of the ta-C coating which affects the inter-bundle junction resistance between the SWCNTN bundles. E-beam evaporated carbon was deposited on the SWCNTNs prior to the ta-C deposition in order to protect the SWCNTN from the intrinsic stress of the ta-C film. The causes of changes in electrical resistance and the effect of evaporated carbon thickness on the changes in electrical resistance and mechanical wear properties have been studied.

  1. Enhanced Microwave Absorption Properties of Carbon Black/Silicone Rubber Coating by Frequency-Selective Surface

    NASA Astrophysics Data System (ADS)

    Yang, Zhaoning; Luo, Fa; Gao, Lu; Qing, Yuchang; Zhou, Wancheng; Zhu, Dongmei

    2016-10-01

    A square frequency-selective surface (FSS) design has been employed to improve the microwave absorption properties of carbon black/silicone rubber (CBSR) composite coating. The FSS is placed on the surface of the CBSR coating. The effects of FSS design parameters on the microwave absorption properties of the CBSR coating have been investigated, including the size and period of the FSS design, and the thickness and permittivity of the coating. Simulation results indicate that the absorption peak for the CBSR coating alone is related to its thickness and electromagnetic parameters, while the combination of the CBSR coating with a FSS can exhibit a new absorption peak in the reflection curve; the frequency of the new absorption peak is determined by the resonance of the square FSS design and tightly depends on the size of the squares, with larger squares in the FSS design leading to a lower frequency of the new absorption peak. The enhancement of the absorption performance depends on achievement of a new absorption peak using a suitable size and period of the FSS design. In addition, the FSS design has a stable frequency response for both transverse electromagnetic (TE) and transverse magnetic (TM) polarizations as the incident angle varies from 0° to 40°. The optimized results indicate that the bandwidth with reflection loss below -5 dB can encompass the whole frequency range from 8 GHz to 18 GHz for thickness of the CBSR coating of only 1.8 mm. The simulation results are confirmed by experiments.

  2. Microstructure and Mechanical Properties of Warm-Sprayed Titanium Coating on Carbon Fiber-Reinforced Plastic

    NASA Astrophysics Data System (ADS)

    Ganesan, Amirthan; Takuma, Okada; Yamada, Motohiro; Fukumoto, Masahiro

    2016-04-01

    Polymer materials are increasingly dominating various engineering fields. Recently, polymer-based composite materials' surface performances—in particular, surface in relative motion—have been improved markedly by thermal spray coating. Despite this recent progress, the deposition of high-strength materials—producing a coating thickness of the order of more than 500 μm—remains highly challenging. In the present work, a highly dense and thick titanium coating was successfully deposited onto the carbon fiber-reinforced plastic (CFRP) substrate using a newly developed high-pressure warm spray (WS) system. The coating properties, such as hardness (300 ± 20 HV) and adhesion strength (8.1 ± 0.5 MPa), were evaluated and correlated with the microstructures of the coating. In addition, a wipe-test and in situ particle velocity and temperature measurement were performed to validate the particle deposition behavior as a function of the nitrogen flow rate in the WS system. It was found that the microstructures, deposition efficiency, and mechanical properties of the coatings were highly sensitive to nitrogen flow rates. The coating porosity increased with increasing nitrogen flow rates; however, the highest density was observed for nitrogen flow rate of 1000 standard liters per minute (SLM) samples due to the high fraction of semi-molten particles in the spray stream.

  3. Hydrogenated amorphous carbon coatings on implants drastically reduce biofilm formation and water permeation

    NASA Astrophysics Data System (ADS)

    Bernsmann, Falk; Laube, Norbert; Baldsiefen, Gerhard; Castellucci, Mattia

    2014-11-01

    Inflammations and crystalline bacterial biofilms (encrustations) remain a major complication in long-term artificial urinary tract drainage. To solve this problem we present urological implants with coatings made of amorphous hydrogenated carbon (a-C:H) that show excellent protection from encrustation in-vitro as well as in-vivo. Part of the success of a-C:H coatings is attributed to their ability to act as a diffusion barrier between an implant and the body, which prevents leaching of solvents from polymeric implants. To further enhance their barrier properties a-C:H coatings are combined with parylene coatings to develop diffusion-barrier multilayer coatings with a total thickness between 0.2 μm and 0.8 μm. The combination of the two types of coatings leads to a reduction of water diffusion by a factor of up to ten with respect to uncoated 25 μm thick polyimide sub-strates. The diffusion of water vapour from a controlled atmospheric pressure chamber through coated foils to a vacuum chamber is measured in a custom-built device.

  4. Analysis of Wear Mechanisms in Low Friction, Nanocomposite AlMgB14-TiB2 Coatings

    SciTech Connect

    Cook, Bruce A; Harringa, J; Anderegg, A; Russell, A M; Qu, Jun; Blau, Peter Julian; Higdon, Clifton; Elmoursi, Alaa A

    2010-01-01

    Recent developments in coating science and technology offer new opportunities to enhance the energy-efficiency and performance of industrial machinery such as hydraulic fluid pumps and motors. The lubricated friction and wear characteristics of two wear-resistant coatings, diamond-like carbon and a nanocomposite material based on AlMgB{sub 14}-50 vol.% TiB{sub 2}, were compared in pin-on-disk tribotests using Mobil DTE-24{trademark} oil as the lubricant. In each case, the pins were fixed 9.53 mm diameter spheres of AISI 52100 steel, the load was 10 N, and the speed 0.5 m/s in all tests. Average steady-state friction coefficient values of 0.10 and 0.08 were measured for the DLC and nanocomposite, respectively. The coatings and their 52100 steel counterfaces were analyzed after the tests by X-ray photoelectron and Auger spectroscopy for evidence of material transfer or tribo-chemical reactions. The low-friction behavior of the boride nanocomposite coating is due to the formation of lubricative boric acid, B(OH){sub 3}. In contrast, the low-friction behavior of the DLC coating is related to the relatively low dielectric constant of the oil-based lubricant, leading to desorption of surface hydrogen from the coating.

  5. Novel Conductive Coatings of Carbon Nanotubes: A Fundamental Study

    DTIC Science & Technology

    2008-02-29

    organic dye from parsley : Parsley leaves were chopped on fine pieces then dissolved in acetone. The mixture was stirred for 3 hours. The extract was then...sensitized solar cell made by coating pigments in an extract from parsley leaves on a nanocrystalline film of TiO 2 has been tested (Figure 6). The...4 2 0 0 2 4 6 8 10 Voltage (V) 16 Figure 6. Solar Cell 17 Figure 7. Output characteristics of a solar cell Absorbance spectrum of parsley 4.5. 4 3.5

  6. Color Anodizing of Titanium Coated Rolled Carbon Steel Plate

    SciTech Connect

    Sarajan, Zohair; Mobarakeh, Hooman Nikbakht; Namiranian, Sohrab

    2011-12-26

    As an important kind of structural materials, the titanium cladded steel plates have the advantages of both metals and have been applied in aviation, spaceflight, chemical and nuclear industries. In this study, the specimens which were prepared under soldering mechanism during rolling were anodized by electrochemical process under a given conditions. The color anodizing takes place by physical phenomenon of color interference. Part of incident light on the titanium oxide is reflected and the other part reflects inside coated titanium layer. Major part of the light which reflects from titanium-oxide interface, reflects again inside of the oxide layer.

  7. Coating of Stainless- and Carbon-Steel Foil

    DTIC Science & Technology

    1951-12-01

    hot sulphuric acid pickling batch, slightly acid nickel sulphate flashing solution and a borax -soda ash neutralizer. 2. Coating Preparation Refractory...Aluminum Hydrate - 15.1 - - - - - - Vanadium Pentoxide (90%) - - 5 5 1.25 2.5 - - 3.5 Iron Oxide - - - 2 - - - - - Chromic Oxide .- 3.9 - - Boric Acid ...83 47.4 59.9 - - - Borax 23.80 21.0 - - 17.9 11.9 - - - Soda Ash 6.44 4.ŗ 5 5 6.1 5.8 - - - Soda Nitre 4.13 0 5 5 4.4 1.6 - - - Fluorspar 3.71 3.2

  8. The structural-phase state of iron-carbon coatings formed by the ultradispersed particles

    SciTech Connect

    Manakova, Irina A. Ozernoy, Alexey N. Tuleushev, Yuriy Zh. Vereshchak, Mikhail F. Volodin, Valeriy N. Zhakanbayev, Yeldar A.

    2014-10-27

    The methods of nuclear gamma-resonance spectroscopy, elemental microanalysis, and X-ray diffraction were used to study nanoscale coatings. The samples were prepared by magnetron sputtering of carbon and iron particles. They alternately were deposited on monocrystalline silicon or polycrystalline corundum substrate moving relative to the plasma flows in the form of sublayers with a thickness of less than 0.6 nm up to the total thickness of 150-500 nm. Solid solutions with the carbon concentrations of up to 7.5, 12.0, 17.6, and 23.9 at% were produced by co-precipitation of ultradispersed particles of iron and carbon. Using method of conversion electron Mössbauer spectroscopy, we detected the anisotropy of orientation of magnetic moments of iron atoms due to texturing of the formed coatings. The deviation of the crystallite orientation from the average value depends on the degree of carbonization. At 550°C, the pearlite eutectic α‐Fe(C)+Fe{sub 3}C is formed from the amorphous structure without formation of intermediate carbides. The relative content of cementite correlates with the amount of carbon in the coating. The formation of the solid solutions-alloys directly during the deposition process confirms the theory of thermal-fluctuation melting of small particles.

  9. An Enzymatic Glucose Sensor Composed of Carbon-Coated Nano Tin Sulfide

    PubMed Central

    Chung, Ren-Jei; Wang, An-Ni; Peng, Shiuan-Ying

    2017-01-01

    In this study, a biosensor, based on a glucose oxidase (GOx) immobilized, carbon-coated tin sulfide (SnS) assembled on a glass carbon electrode (GCE) was developed, and its direct electrochemistry was investigated. The carbon coated SnS (C-SnS) nanoparticle was prepared through a simple two-step process, using hydrothermal and chemical vapor deposition methods. The large reactive surface area and unique electrical potential of C-SnS could offer a favorable microenvironment for facilitating electron transfer between enzymes and the electrode surface. The structure and sensor ability of the proposed GOx/C-SnS electrode were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and cyclic voltammetry study (CV). PMID:28336872

  10. Copper nanowire coated carbon fibers as efficient substrates for detecting designer drugs using SERS.

    PubMed

    Halouzka, Vladimir; Halouzkova, Barbora; Jirovsky, David; Hemzal, Dusan; Ondra, Peter; Siranidi, Eirini; Kontos, Athanassios G; Falaras, Polycarpos; Hrbac, Jan

    2017-04-01

    Miniature Surface Enhanced Raman Scattering (SERS) sensors were fabricated by coating the carbon fiber microelectrodes with copper nanowires. The coating procedure, based on anodizing the copper wire in ultrapure water followed by cathodic deposition of the anode-derived material onto carbon fiber electrodes, provides a "clean" copper nanowire network. The developed miniature (10µm in diameter and 2mm in length) and nanoscopically rough SERS substrates are applicable in drug sensing, as shown by the detection and resolving of a range of seized designer drugs in trace amounts (microliter volumes of 10(-10)-10(-12)M solutions). The copper nanowire modified carbon microfiber substrates could also find further applications in biomedical and environmental sensing.

  11. Anodic stripping voltammetric determination of mercury using multi-walled carbon nanotubes film coated glassy carbon electrode.

    PubMed

    Yi, Hongchao

    2003-10-01

    An electrochemical method for the determination of trace levels of mercury based on a multi-walled carbon nanotubes (MWNT) film coated glassy carbon electrode (GCE) is described. In 0.1 mol L(-1) HCl solution containing 0.02 mol L(-1) KI, Hg(2+) was firstly preconcentrated at the MWNT film and then reduced at -0.60 V. During the anodic potential sweep, reduced mercury was oxidized, and then a sensitive and well-defined stripping peak at about -0.20 V appeared. Under identical conditions, a MWNT film coated GCE greatly enhances the stripping peak current of mercury in contrast to a bare GCE. Low concentrations of I(-) remarkably improve the determining sensitivity, since this increases the accumulation efficiency of Hg(2+) at the MWNT film coated GCE. The stripping peak current is proportional to the concentration of Hg(2+) over the range 8 x 10(-10)-5 x 10(-7) mol L(-1). The lowest detectable concentration of Hg(2+) is 2 x 10(-10) mol L(-1) at 5 min accumulation. The relative standard deviation (RSD) at 1 x 10(-8) mol L(-1) Hg(2+) was about 6% ( n=10). By using this proposed method, Hg(2+) in some water samples was determined, and the results were compared with those obtained by atomic absorption spectrometry (AAS). The two results are similar, suggesting that the MWNT-film coated GCE has great potential in practical analysis.

  12. Electron Cloud in Steel Beam Pipe vs Titanium Nitride Coated and Amorphous Carbon Coated Beam Pipes in Fermilab's Main Injector

    SciTech Connect

    Backfish, Michael

    2013-04-01

    This paper documents the use of four retarding field analyzers (RFAs) to measure electron cloud signals created in Fermilab’s Main Injector during 120 GeV operations. The first data set was taken from September 11, 2009 to July 4, 2010. This data set is used to compare two different types of beam pipe that were installed in the accelerator. Two RFAs were installed in a normal steel beam pipe like the rest of the Main Injector while another two were installed in a one meter section of beam pipe that was coated on the inside with titanium nitride (TiN). A second data run started on August 23, 2010 and ended on January 10, 2011 when Main Injector beam intensities were reduced thus eliminating the electron cloud. This second run uses the same RFA setup but the TiN coated beam pipe was replaced by a one meter section coated with amorphous carbon (aC). This section of beam pipe was provided by CERN in an effort to better understand how an aC coating will perform over time in an accelerator. The research consists of three basic parts: (a) continuously monitoring the conditioning of the three different types of beam pipe over both time and absorbed electrons (b) measurement of the characteristics of the surrounding magnetic fields in the Main Injector in order to better relate actual data observed in the Main Injector with that of simulations (c) measurement of the energy spectrum of the electron cloud signals using retarding field analyzers in all three types of beam pipe.

  13. Carbide Coatings for Nickel Alloys, Graphite and Carbon/Carbon Composites to be used in Fluoride Salt Valves

    SciTech Connect

    Nagle, Denis; Zhang, Dajie

    2015-10-22

    The focus of this research was concerned with developing materials technology that supports the evolution of Generation IV Advanced High Temperature Reactor (AHTR) concepts. Specifically, we investigate refractory carbide coatings for 1) nickel alloys, and 2) commercial carbon-carbon composites (CCCs). Numerous compelling reasons have driven us to focus on carbon and carbide materials. First, unlike metals, the strength and modulus of CCCs increase with rising temperature. Secondly, graphite and carbon composites have been proven effective for resisting highly corrosive fluoride melts such as molten cryolite [Na₃AlF₆] at ~1000°C in aluminum reduction cells. Thirdly, graphite and carbide materials exhibit extraordinary radiation damage tolerance and stability up to 2000°C. Finally, carbides are thermodynamically more stable in liquid fluoride salt than the corresponding metals (i.e. Cr and Zr) found in nickel based alloys.

  14. Final Technical Report CONDUCTIVE COATINGS FOR SOLAR CELLS USING CARBON NANOTUBES

    SciTech Connect

    Paul J Glatkowski; Jorma Peltola; Christopher Weeks; Mike Trottier; David Britz

    2007-09-30

    US Department of Energy (DOE) awarded a grant for Eikos Inc. to investigate the feasibility of developing and utilizing Transparent Conducting Coatings (TCCs) based on carbon nanotubes (CNT) for solar cell applications. Conventional solar cells today employ metal oxide based TCCs with both Electrical Resistivity (R) and Optical Transparency (T), commonly referred to as optoelectronic (RT) performance significantly higher than with those possible with CNT based TCCs available today. Transparent metal oxide based coatings are also inherently brittle requiring high temperature in vacuum processing and are thus expensive to manufacture. One such material is indium tin oxide (ITO). Global demand for indium has recently increased rapidly while supply has diminished causing substantial spikes in raw material cost and availability. In contrast, the raw material, carbon, needed for CNT fabrication is abundantly available. Transparent Conducting Coatings based on CNTs can overcome not only cost and availability constraints while also offering the ability to be applied by existing, low cost process technologies under ambient conditions. Processes thus can readily be designed both for rigid and flexible PV technology platforms based on mature spray or dip coatings for silicon based solar cells and continuous roll to roll coating processes for polymer solar applications.

  15. The Electrochemical Behavior of Zn-Mn Alloy Coating in Carbonated Concrete Solution

    NASA Astrophysics Data System (ADS)

    Touazi, S.; Bučko, M.; Makhloufi, L.; Legat, A.; Bajat, J. B.

    2016-05-01

    In order to improve the protective performance of Zn coating on reinforcing steel in concrete, the electrochemical deposition of Zn-Mn coatings was conducted on steel surface. The morphology, chemical and phase compositions of Zn-Mn coatings obtained from sulfate-citrate bath were investigated in the first part of paper. In the second part, the obtained deposits were tested in solution simulating carbonated concrete, consisting of NaHCO3 and Na2CO3. Data obtained from Tafel analysis showed higher corrosion resistance for Zn-Mn alloy deposits obtained at -1700 and -1800mV versus SCE, when compared to pure Zn deposit. Impedance spectroscopy investigations revealed that the total impedance of Zn-Mn coatings increased steadily with time, and was significantly higher as compared to pure Zn after 24h in corrosion solution. On the contrary, for pure Zn, the impedance increased in the first 12h, and then decreased during prolonged exposure time, which can be explained by rapid growth of nonprotective white rust and the degradation of zinc coating, as was confirmed by optical microscope after 24h of immersion in carbonated concrete pore solution.

  16. Graphene coating makes carbon nanotube aerogels superelastic and resistant to fatigue

    NASA Astrophysics Data System (ADS)

    Kim, Kyu Hun; Oh, Youngseok; Islam, M. F.

    2012-09-01

    Lightweight materials that are both highly compressible and resilient under large cyclic strains can be used in a variety of applications. Carbon nanotubes offer a combination of elasticity, mechanical resilience and low density, and these properties have been exploited in nanotube-based foams and aerogels. However, all nanotube-based foams and aerogels developed so far undergo structural collapse or significant plastic deformation with a reduction in compressive strength when they are subjected to cyclic strain. Here, we show that an inelastic aerogel made of single-walled carbon nanotubes can be transformed into a superelastic material by coating it with between one and five layers of graphene nanoplates. The graphene-coated aerogel exhibits no change in mechanical properties after more than 1 × 106 compressive cycles, and its original shape can be recovered quickly after compression release. Moreover, the coating does not affect the structural integrity of the nanotubes or the compressibility and porosity of the nanotube network. The coating also increases Young's modulus and energy storage modulus by a factor of ~6, and the loss modulus by a factor of ~3. We attribute the superelasticity and complete fatigue resistance to the graphene coating strengthening the existing crosslinking points or `nodes' in the aerogel.

  17. Coating of porous carbon for use in lithium air batteries

    DOEpatents

    Amine, Khalil; Lu, Jun; Du, Peng; Lei, Yu; Elam, Jeffrey W

    2015-04-14

    A cathode includes a carbon material having a surface, the surface having a first thin layer of an inert material and a first catalyst overlaying the first thin layer, the first catalyst including metal or metal oxide nanoparticles, wherein the cathode is configured for use as the cathode of a lithium-air battery.

  18. Chemical Sensing with Polyaniline Coated Single-Walled Carbon Nanotubes

    SciTech Connect

    Ding, Mengning; Tang, Yifan; Gou, Pingping; Reber, Michael J; Star, Alexander

    2011-01-25

    Single-walled carbon nanotube/polyaniline (SWNT/PAni) nanocomposite with controlled core/shell morphology was synthesized by a noncovalent functionalization approach. Unique electron interactions between the SWNT core and the PAni shell were studied electrochemically and spectroscopically, and superior sensor performance to chemical gases and vapors was demonstrated.

  19. Effect of Carbon Black on Dielectric and Microwave Absorption Properties of Carbon Black/Cordierite Plasma-Sprayed Coatings

    NASA Astrophysics Data System (ADS)

    Su, Jinbu; Zhou, Wancheng; Liu, Yi; Qing, Yuchang; Luo, Fa; Zhu, Dongmei

    2015-06-01

    Carbon black (CB)/cordierite composite coatings with different CB contents were fabricated by a multi-function micro-plasma spraying system developed by the Second Artillery Engineering College. Scanning electron microscopy was employed to investigate the microstructure of the spray-dried powders and as-sprayed coatings. The complex permittivities of the coatings and powders with different CB contents were investigated at the frequency of 8.2-12.4 GHz. The results show that both real and imaginary part of the permittivity increase with increasing CB content, which can be ascribed to the increase of the number of micro-capacitors and the polarization centers. Reflection loss of the as-sprayed coatings with different CB contents and thicknesses was calculated according to the transmission line theory. The coating with 4.54% CB content and 3.0 mm thickness shows optical microwave absorption with a minimum reflection loss of -23.90 dB at 10.13 GHz and reflection loss less than -9 dB over the whole investigated frequency.

  20. Preparation and characterization of porous carbon material-coated solid-phase microextraction metal fibers.

    PubMed

    Zhu, Fang; Guo, Jiaming; Zeng, Feng; Fu, Ruowen; Wu, Dingcai; Luan, Tiangang; Tong, Yexiang; Lu, Tongbu; Ouyang, Gangfeng

    2010-12-10

    Two kinds of porous carbon materials, including carbon aerogels (CAs), wormhole-like mesoporous carbons (WMCs), were synthesized and used as the coatings of solid-phase microextraction (SPME) fibers. By using stainless steel wire as the supporting core, six types of fibers were prepared with sol-gel method, direct coating method and direct coating plus sol-gel method. Headspace SPME experiments indicated that the extraction efficiencies of the CA fibers are better than those of the WMC fibers, although the surface area of WMCs is much higher than that of CAs. The sol-gel-CA fiber (CA-A) exhibited excellent extraction properties for non-polar compounds (BTEX, benzene, toluene, ethylbenzene, o-xylene), while direct-coated CA fiber (CA-B) presented the best performance in extracting polar compounds (phenols). The two CA fibers showed wide linear ranges, low detection limits (0.008-0.047μgL(-1) for BTEX, 0.15-5.7μgL(-1) for phenols) and good repeatabilities (RSDs less than 4.6% for BTEX, and less than 9.5% for phenols) and satisfying reproducibilities between fibers (RSDs less than 5.2% for BTEX, and less than 9.9% for phenols). These fibers were successfully used for the analysis of water samples from the Pearl River, which demonstrated the applicability of the home-made CA fibers.

  1. Multiple free electron laser pulse illumination of a carbon coated silicon substrate

    NASA Astrophysics Data System (ADS)

    Siemer, Björn; Hoger, Tim; Rutkowski, Marco; Menneken, Martina; Düsterer, Stefan; Zacharias, Helmut

    2013-05-01

    The fourth generation of XUV-, soft x-ray- and x-ray-light sources, like the free electron lasers FLASH and FERMI@Elettra, leads to new seminal scientific findings and technical challenges. For the facilities the question of the beam transport is of utmost importance. To provide a good reflectivity over a large range of photon energies up to about 300 eV mostly carbon coated silicon mirrors illuminated under gracing incidence angle are mostly chosen. Thereby the coating for the mirrors must tolerate high light intensities at high photon energies and also high repetition rates. In the present experiment an amorphous carbon coated silicon substrate was illuminated at photon energies of 21 nm (58 eV) and an average pulse energy of ~27 μJ. The ellipsoidal spot size of 300 μm × 600 μm at FLASH leads to a fluence of 0.019 J/cm2. The influence of multiple (100 - 20.000) light pulses to the coated surface is analyzed. Depending on the number of pulses a change in reflectivity is visible under a light microscope. Both an AFM profile and measurements with a profilometer yield no topological changes. The investigation of the illuminated spots with a microfocus Raman spectrometer shows a decrease of the carbon signal at higher pulse repetition rates.

  2. Production of carbon nano-tubes via CCVD method and their corrosion protection performance in epoxy based coatings

    NASA Astrophysics Data System (ADS)

    Raza, M. A.; Ghauri, F. A.; Awan, M. S.; Farooq, A.; Ahmad, R.

    2016-08-01

    Good yield of carbon products was obtained by catalytic chemical vapor deposition (CCVD) technique using 100-500mg of ferrocene catalyst at temperature of 900 °C and acetylene flow rate of 150-200cc/min. The effects of amount of ferrocene, temperature and hydrocarbons precursors on the yield of carbon nanomaterial's was calculated and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) andenergy- dispersive X-ray spectroscopy (EDS). Good yield of carbon nanomaterials primarily consisted of carbon nanotubes (CNTs) and carbon nanoparticles was obtained. CNTs obtained after purification were dispersed in epoxy resin to produce composite coatings which were coated on stainless steel 316L. The coated stainless steel samples’ corrosion behavior was studied using open circuit potential (OCP), cyclic polarization and electrochemical impedance spectroscopy (EIS) techniques. Results showed that epoxy coating containing 4 wt. % of CNTs offered improved corrosion resistance to stainless steel.

  3. Carbon film coating on gas diffusion layer for proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Lin, Jui-Hsiang; Chen, Wei-Hung; Su, Shih-Hsuan; Liao, Yuan-Kai; Ko, Tse-Hao

    This study discusses a novel process to increase the performance of proton exchange membrane fuel cells (PEMFC). In order to improve the electrical conductivity and reduce the surface indentation of the carbon fibers, we modified the carbon fibers with pitch-based carbon materials (mesophase pitch and coal tar pitch). Compared with the gas diffusion backing (GDB), GDB-A240 and GDB-MP have 32% and 33% higher current densities at 0.5 V, respectively. Self-made carbon paper with the addition of a micro-porous layer (MPL) (GDL-A240 and GDL-MP) show improved performance compared with GDB-A240 and GDB-MP. The current densities of GDL-A240 and GDL-MP at 0.5 V increased by 37% and 31% compared with GDL, respectively. This study combines these two effects (carbon film and MPL coating) to promote high current density in a PEMFC.

  4. Investigation of thermostability of resistive coatings based on carbon-filled polyurethane

    NASA Astrophysics Data System (ADS)

    Potekaev, A. I.; Malinovskaya, T. D.; Melentyev, S. V.; Pavlov, S. V.

    2015-10-01

    The influence of thermal treatment and dispersed carbon fillers on the thermostability of polyurethane binder is established. The conditions of thermal treatment of thick film composite resistive coatings have been defined to be further used in structures of electric heaters. It was found that the thermostability of resistive coatings based on polyurethane varnish Kontracid D3010 is reached by means of thermal treatment at a temperature of 120°C during 2 hours and is characterized by the completion of a reaction between the hydroxyl and isocyanate groups.

  5. Modification of granular activated carbon surface by chitosan coating for geosmin removal: sorption performances.

    PubMed

    Vinitnantharat, S; Rattanasirisophon, W; Ishibashi, Y

    2007-01-01

    This study presents the results of the sorption performances for geosmin removal by sorption onto granular activated carbons (GAC) manufactured from different raw materials of coconut shell and bituminous coal. The surface of GAC was modified by chitosan coating. The 90% deacetylated chitosan flakes were used for coating on GAC with the GAC: chitosan ratio of 5:1. The surface of GAC was characterised by scanning electron microscope (SEM) analysis, Fourier transform infrared spectroscopy and measurement of the pH solution of GAC samples. The sorption of geosmin onto the chitosan for both uncoated and coated GACs could be described by the Freundlich adsorption model. Data revealed that the sequence of Freundlich constant (K(F)) was chitosan coated bitominous coal (CB) > uncoated bituminous coal (UB) > chitos approximately equal to an coated coconut shell (CC) approximately equal to uncoated coconut shell (UC). The bituminous coal based GAC with chitosan coating had a maximum capacity of 23.57 microg/g which was approximately two-fold of uncoated bituminous coal based GAC. Two simplified kinetic models, pseudo-first order and pseudo-second order, were tested to investigate the sorption mechanisms. It was found that the intraparticle diffusion was a rate controlling step for the sorption and followed the pseudo-second order equation.

  6. Mechanical and tribological behavior of silicon nitride and silicon carbon nitride coatings for total joint replacements.

    PubMed

    Pettersson, M; Tkachenko, S; Schmidt, S; Berlind, T; Jacobson, S; Hultman, L; Engqvist, H; Persson, C

    2013-09-01

    Total joint replacements currently have relatively high success rates at 10-15 years; however, increasing ageing and an active population places higher demands on the longevity of the implants. A wear resistant configuration with wear particles that resorb in vivo can potentially increase the lifetime of an implant. In this study, silicon nitride (SixNy) and silicon carbon nitride (SixCyNz) coatings were produced for this purpose using reactive high power impulse magnetron sputtering (HiPIMS). The coatings are intended for hard bearing surfaces on implants. Hardness and elastic modulus of the coatings were evaluated by nanoindentation, cohesive, and adhesive properties were assessed by micro-scratching and the tribological performance was investigated in a ball-on-disc setup run in a serum solution. The majority of the SixNy coatings showed a hardness close to that of sintered silicon nitride (~18 GPa), and an elastic modulus close to that of cobalt chromium (~200 GPa). Furthermore, all except one of the SixNy coatings offered a wear resistance similar to that of bulk silicon nitride and significantly higher than that of cobalt chromium. In contrast, the SixCyNz coatings did not show as high level of wear resistance.

  7. Bioinspired and biocompatible carbon nanotube-Ag nanohybrid coatings for robust antibacterial applications.

    PubMed

    Nie, Chuanxiong; Yang, Ye; Cheng, Chong; Ma, Lang; Deng, Jie; Wang, Lingren; Zhao, Changsheng

    2017-03-15

    The design of self-sterilizing surfaces with favorable biocompatibility is acknowledged as an effective approach to deal with the bacterial infections of biomedical devices. In this study, we report an intriguing protocol for the large-scale fabrication of self-sterilizing and biocompatible surface film coatings by using polymer shielded silver nanoparticle loaded oxidized carbon nanotube (AgNPs@oCNT) nano-dispersions. To achieve the antibacterial coatings, the bioinspired positively charged and negatively charged AgNPs@oCNTs were alternately deposited onto substrates by spray-coating assisted layer-by-layer assembly. Then the bacterial inhibitory zones, optical density value monitoring, bacterial killing efficiency and adhesion were investigated; and all the results revealed that the AgNPs@oCNTs thin film coatings exhibited robust and long-term antibacterial activity against both Gram negative and Gram positive bacteria. Moreover, due to the shielding effects of polymer layers, the coatings showed extraordinary blood compatibility and limited toxicity against human umbilical vein endothelial cells. It is believed that the proposed large-scale fabrication of bactericidal, blood and cell compatible AgNPs@oCNT based thin film coatings will have great potential to forward novel operational pathogenic inhibition strategies to avoid undesired bacterial contaminations of biomedical implants or biological devices.

  8. Laser Treatment of Electro-Spark Coatings Deposited in the Carbon Steel Substrate with using Nanostructured WC-Cu Electrodes

    NASA Astrophysics Data System (ADS)

    Radek, Norbert; Bartkowiak, Konrad

    The aim of this work was to investigate the influence of laser treatment for the improving mechanical and tribological properties coatings fabricated in the C45 carbon steel by ESD process. The studies were conducted using WC-Cu electrodes produced by sintering nanostructural powders and molten with a laser beam. The tests proved that ESD WC-Cu coatings are characterized by lower hardness and friction coefficient, but higher roughness. The result of laser processing improves structure by refinement, healing of microcracks and pores of ESD coatings. Laser treated ESD coatings can be applied in sliding friction pairs and as protective coatings.

  9. Robust diamond-like Fe-Si network in the zero-strain NaxFeSiO4 cathode

    SciTech Connect

    Ye, Zhuo; Zhao, Xin; Li, Shouding; Wu, Shunqing; Wu, Ping; Nguyen, Manh Cuong; Guo, Jianghuai; Mi, Jinxiao; Gong, Zhengliang; Zhu, Zi -Zhong; Yang, Yong; Wang, Cai -Zhuang; Ho, Kai -Ming

    2016-07-14

    Sodium orthosilicates Na2MSiO4 (M denotes transition metals) have attracted much attention due to the possibility of exchanging two electrons per formula unit. In this work, we report a group of sodium iron orthosilicates Na2FeSiO4. Their crystal structures are characterized by a diamond-like Fe-Si network. The Fe-Si network is quite robust against the charge/discharge process, which explains the high structural stability observed in experiment. Furthermore, using the density functional theory within the GGA + U framework and X-ray diffraction studies, the crystal structures and structural stabilities during the sodium extraction/re-insertion process are systematically investigated.

  10. Synthesis of SiC nanowires with in-situ deposition of carbon coating.

    PubMed

    Yang, Wen; Araki, Hiroshi; Tang, Chengchun; Hu, Quanli; Suzuki, Hiroshi; Noda, Tetsuji

    2005-02-01

    SiC nanowires are effective reinforcement materials in ceramic matrix composites. A compliant coating such as carbon on nanowires is necessary in order to moderate the nanowire/matrix interfacial bounding for taking the most advantages of SiC nanowires. SiC nanowires with an in-situ deposition of carbon shell coating were fabricated by a novel chemical vapor growth process. Highresolution transmission electron microscopy examinations showed that the nanowires consisted of a single crystal beta-SiC core with an amorphous carbon shell 2-5 nm in thickness. The nanowires were straight with a length generally over 10 microm and a diameter 15-150 nm. The growth direction of the core SiC nanowires is (111). A simple three-step growth model for SiC nanowires was proposed based on a vapor-solid growth mechanism. Because the carbon-coated nanowires were grown directly on continuous Tyranno-SA SiC fibers, in-situ application of the present technique on the fabrication of SiC nanowire-reinforced SiC/SiC composites is expected.

  11. A highly durable fuel cell electrocatalyst based on double-polymer-coated carbon nanotubes.

    PubMed

    Berber, Mohamed R; Hafez, Inas H; Fujigaya, Tsuyohiko; Nakashima, Naotoshi

    2015-11-23

    Driven by the demand for the commercialization of fuel cell (FC) technology, we describe the design and fabrication of a highly durable FC electrocatalyst based on double-polymer-coated carbon nanotubes for use in polymer electrolyte membrane fuel cells. The fabricated electrocatalyst is composed of Pt-deposited polybenzimidazole-coated carbon nanotubes, which are further coated with Nafion. By using this electrocatalyst, a high FC performance with a power density of 375 mW/cm(2) (at 70 ˚C, 50% relative humidity using air (cathode)/H2(anode)) was obtained, and a remarkable durability of 500,000 accelerated potential cycles was recorded with only a 5% loss of the initial FC potential and 20% loss of the maximum power density, which were far superior properties compared to those of the membrane electrode assembly prepared using carbon black in place of the carbon nanotubes. The present study indicates that the prepared highly durable fuel cell electrocatalyst is a promising material for the next generation of PEMFCs.

  12. CO2 sensing at room temperature using carbon nanotubes coated core fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Shivananju, B. N.; Yamdagni, S.; Fazuldeen, R.; Sarin Kumar, A. K.; Hegde, G. M.; Varma, M. M.; Asokan, S.

    2013-06-01

    The sensing of carbon dioxide (CO2) at room temperature, which has potential applications in environmental monitoring, healthcare, mining, biotechnology, food industry, etc., is a challenge for the scientific community due to the relative inertness of CO2. Here, we propose a novel gas sensor based on clad-etched Fiber Bragg Grating (FBG) with polyallylamine-amino-carbon nanotube coated on the surface of the core for detecting the concentrations of CO2 gas at room temperature, in ppm levels over a wide range (1000 ppm-4000 ppm). The limit of detection observed in polyallylamine-amino-carbon nanotube coated core-FBG has been found to be about 75 ppm. In this approach, when CO2 gas molecules interact with the polyallylamine-amino-carbon nanotube coated FBG, the effective refractive index of the fiber core changes, resulting in a shift in Bragg wavelength. The experimental data show a linear response of Bragg wavelength shift for increase in concentration of CO2 gas. Besides being reproducible and repeatable, the technique is fast, compact, and highly sensitive.

  13. Rapid synthesis of inherently robust and stable superhydrophobic carbon soot coatings

    NASA Astrophysics Data System (ADS)

    Esmeryan, Karekin D.; Castano, Carlos E.; Bressler, Ashton H.; Abolghasemibizaki, Mehran; Mohammadi, Reza

    2016-04-01

    The fabrication of superhydrophobic coatings using a candle flame or rapeseed oil has become very attractive as a novel approach for synthesis of water repellent surfaces. Here, we report an improved, simplified and time-efficient method for the preparation of robust superhydrophobic carbon soot that does not require any additional stabilizers or chemical treatment. The soot's inherent stabilization is achieved using a specially-designed cone-shaped aluminum chimney, mounted over an ignited paper-based wick immersed in a rapeseed oil. Such configuration decreases the level of oxygen during the process of combustion; altering the ratio of chemical bonds in the soot. As a result, the fractal-like network of the carbon nanoparticles is converted into dense and fused carbon chains, rigidly coupled to the substrate surface. The modified carbon coating shows thermal sustainability and retains superhydrophobicity up to ∼300 °C. Furthermore, it demonstrates a low contact angle hysteresis of 0.7-1.2° accompanied by enhanced surface adhesion and mechanical durability under random water flows. In addition, the soot's deposition rate of ∼1.5 μm/s reduces the exposure time of the substrate to heat and consequently minimizes the thermal effects, allowing the creation of superhydrophobic coatings on materials with low thermal stability (e.g. wood or polyethylene).

  14. A highly durable fuel cell electrocatalyst based on double-polymer-coated carbon nanotubes

    PubMed Central

    Berber, Mohamed R.; Hafez, Inas H.; Fujigaya, Tsuyohiko; Nakashima, Naotoshi

    2015-01-01

    Driven by the demand for the commercialization of fuel cell (FC) technology, we describe the design and fabrication of a highly durable FC electrocatalyst based on double-polymer-coated carbon nanotubes for use in polymer electrolyte membrane fuel cells. The fabricated electrocatalyst is composed of Pt-deposited polybenzimidazole-coated carbon nanotubes, which are further coated with Nafion. By using this electrocatalyst, a high FC performance with a power density of 375 mW/cm2 (at 70 ˚C, 50% relative humidity using air (cathode)/H2(anode)) was obtained, and a remarkable durability of 500,000 accelerated potential cycles was recorded with only a 5% loss of the initial FC potential and 20% loss of the maximum power density, which were far superior properties compared to those of the membrane electrode assembly prepared using carbon black in place of the carbon nanotubes. The present study indicates that the prepared highly durable fuel cell electrocatalyst is a promising material for the next generation of PEMFCs. PMID:26594045

  15. Electrochemistry of norepinephrine on carbon-coated nickel magnetic nanoparticles modified electrode and analytical applications.

    PubMed

    Bian, Chunli; Zeng, Qingxiang; Xiong, Huayu; Zhang, Xiuhua; Wang, Shengfu

    2010-08-01

    A carbon-coated nickel magnetic nanoparticles modified glassy carbon electrode (C-Ni/GCE) was fabricated. The carbon-coated nickel magnetic nanoparticles were characterized with transmission electron microscopy (TEM). The electrochemical behaviors of norepinephrine (NE) were investigated on the modified electrode by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The carbon-coated nickel magnetic nanoparticles showed excellent electrocatalytic activity for the electrochemical redox of NE. NE exhibited two couples of well-defined redox peaks on C-Ni/GCE over the potential range from -0.4 to 0.8V in phosphate buffer solution (PBS) (pH=7.0). The redox mechanism for NE was proposed. DPV response of NE on the C-Ni/GCE showed that the catalytic oxidative peak current was linear with the square root concentration of NE in the range of 2.0 x 10(-7) to 8.0 x 10(-5)M, with a detection limit of 6.0 x 10(-8)M. The C-Ni/GCE showed good sensitivity, selectivity and stability for the determination of NE.

  16. Stress rupture behavior of silicon carbide coated, low modulus carbon/carbon composites

    SciTech Connect

    Rozak, G.A.; Wallace, J.F.

    1988-01-01

    The disadvantages of carbon-carbon composites, in addition to the oxidation problem, are low thermal expansion, expensive fabrication procedures, and poor off axis properties. The background of carbon-carbon composites, their fabrication, oxidation, oxidation protection and mechanical testing in flexure are discussed.

  17. SiC multi-layer protective coating on carbon obtained by thermionic vacuum arc method

    NASA Astrophysics Data System (ADS)

    Ciupina, V.; Lungu, C. P.; Vladoiu, R.; Epure, T.-D.; Prodan, G.; Roşca, C.; Porosnicu, C.; Jepu, I.; Belc, M.; Prodan, M.; Stanescu, I. M.; Stefanov, C.; Contulov, M.; Mandes, A.; Dinca, V.; Vasile, E.; Zarovschi, V.; Nicolescu, V.

    2013-09-01

    SiC single-layer or multi-layer on C used to improve the oxidation resistance and tribological properties of C have been obtained by Thermionic Vacuum Arc (TVA) method. The 200nm thickness carbon thin films was deposed on glass or Si substrate and then 100÷500 nm thickness SiC successively layers on carbon thin film was deposed. The microstructure and mechanical characteristics of as-prepared SiC coating were investigated by Transmission Electron Microscopy (TEM, STEM), Energy Dispersive X-Ray Spectroscopy (EDS), Electron Scattering Chemical Analysis (ESCA) and tribological techniques. Samples containing SiC single-layer or multi-layer coating on carbon were investigated up to 1000°C. The results of thermal treatments reveals the increase of oxidation resistance with increase of the number of SiC layers. The mechanism of oxidation protection is based on the reaction between SiC and elemental oxygen resulting SiO2 and CO. The tribological behavior of SiC coatings was evaluated with a tribometer with ball-on-disk configuration from CSM device with 6mm diameter sapphire ball, sliding speed in dry conditions being 0.2m/s, with normal contact loads of 0.5N, 1N, 1.5N and 2N, under unlubricated conditions. The friction coefficient on SiC was compared with the friction coefficient on uncoated carbon layer. Electrical surface resistance of SiC coating on carbon at different temperatures was measured comparing the potential drop on the sample with the potential drop on a series standard resistance in constant mode.

  18. Metal coated functionalized single-walled carbon nanotubes for composite applications

    NASA Astrophysics Data System (ADS)

    Zeng, Qiang

    This study is considered as a method for producing multifunctional composite materials by using metals coated Single-walled Carbon Nanotubes (SWCNTs). In this research, various metals (Ni, Cu, Ag) were successfully deposited onto the surface of SWCNTs. It has been found that homogenous dispersion and dense nucleation sites are the necessary conditions to form uniform coatings on SWCNTs. Functionalization has been applied to achieve considerable improvement in the dispersion of purified SWCNTs and creates more nucleation sites for subsequent metal deposition. A three-step electroless plating approach was used and the coating mechanism is described in the paper. The samples were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Raman spectroscopy, fourier transform infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDX). Bulk copper/aluminum-SWNT composites were processed by powder metallurgy with wet mixing techniques. Coated SWCNTs were well dispersed in the metal matrix. Cold pressing followed by sintering was applied to control porosity. The relationships between hardness and SWCNTs addition were discussed. Ni-SWCNTs composite coatings were prepared by electro-composite deposition. SWCNTs were suspended in a Ni deposition electrolyte and deposited together with nickel during electrodeposition. SWCNTs concentrations in the coatings were found to be related to the SWCNTs concentration in the solution, current density and agitation rate. The microstructure of the coatings has been examined by electron microscopy. Ni coated SWCNTs were also incorporated into the high temperature Bismaleimide (BMI)/graphite composite to improve Electromagnetic Interference (EMI) shielding and surface conductivity. The vacuum assisted resin transfer molding (VARTM) was used to process these composites. Surface and volume resistivity and EMI shielding effectiveness of the composites

  19. Development of a carbon-nanoparticle-coated stirrer for stir bar sorptive extraction by a simple carbon deposition in flame.

    PubMed

    Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

    2016-03-01

    Stir bar sorptive extraction is an environmentally friendly microextraction technique based on a stir bar with various sorbents. A commercial stirrer is a good support, but it has not been used in stir bar sorptive extraction due to difficult modification. A stirrer was modified with carbon nanoparticles by a simple carbon deposition process in flame and characterized by scanning electron microscopy and energy-dispersive X-ray spectrometry. A three-dimensional porous coating was formed with carbon nanoparticles. In combination with high-performance liquid chromatography, the stir bar was evaluated using five polycyclic aromatic hydrocarbons as model analytes. Conditions including extraction time and temperature, ionic strength, and desorption solvent were investigated by a factor-by-factor optimization method. The established method exhibited good linearity (0.01-10 μg/L) and low limits of quantification (0.01 μg/L). It was applied to detect model analytes in environmental water samples. No analyte was detected in river water, and five analytes were quantified in rain water. The recoveries of five analytes in two samples with spiked at 2 μg/L were in the range of 92.2-106% and 93.4-108%, respectively. The results indicated that the carbon nanoparticle-coated stirrer was an efficient stir bar for extraction analysis of some polycyclic aromatic hydrocarbons.

  20. Mesoporous carbon-zirconium oxide nanocomposite derived from carbonized metal organic framework: A coating for solid-phase microextraction.

    PubMed

    Saraji, Mohammad; Mehrafza, Narges

    2016-08-19

    In this paper, a mesoporous carbon-ZrO2 nanocomposite was fabricated on a stainless steel wire for the first time and used as the solid-phase microextraction coating. The fiber was synthesized with the direct carbonization of a Zr-based metal organic framework. With the utilization of the metal organic framework as the precursor, no additional carbon source was used for the synthesis of the mesoporous carbon-ZrO2 nanocomposite coating. The fiber was applied for the determination of BTEX compounds (benzene, toluene, ethylbenzene and m, p-xylenes) in different water samples prior to gas chromatography-flame ionization detection. Such important experimental factors as synthesis time and temperature, salt concentration, equilibrium and extraction time, extraction temperature, desorption time and desorption temperature were studied and optimized. Good linearity in the concentration range of 0.2-200μgL(-1) and detection limits in the range of 0.05-0.56μgL(-1) was achieved for BTEX compounds. The intra- and inter-day relative standard deviations were in the range of 3.5-4.8% and 4.9-6.7%, respectively. The prepared fiber showed high capability for the analysis of BTEX compounds in different water and wastewater samples with good relative recoveries in the range of 93-107%.