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Sample records for coated in738 components

  1. Comparison of Thermal Properties of Thermal Barrier Coating Deposited on IN738 Using Standard Air Plasma Spray with 100HE Plasma Spray System

    SciTech Connect

    Uppu, Nalini; Mensah, Patrick F.; Ofori, Daniel

    2006-07-31

    Thermal barrier coatings (TBCs) have low thermal conductivity values and have a primary benefit of providing an insulating layer that reduces the coated substrate temperature and mitigates the effects of hot streaking or uneven temperature distributions. Thermal conductivity, k, is a thermo-physical property that can be derived from the thermal diffusivity, α, of the specimen. It can be obtained from the formula k = α cp ρ, where cp is specific heat and ρ is the density of the material. Thermal conductivity, k, describes the quantity of heat that passes through a unit area of sample in unit time with a temperature gradient present. This thermal property of TBCs can be measured by flash method in which a nearly instantaneous pulse of energy (usually laser or other discharge source) is input to the frontal surface of a material sample and the temperature changes are measured on back side of sample with and INSb infrared detector as shown in Fig.1. A laser flash test has the advantage of being fast while providing values with excellent accuracy and reproducibility. In this study, an instantaneous triangular heat pulse from a laser heat flash system (FL5000) made by Anter corporation, Pittsburgh, PA was used. The technique satisfies the ASTM E 1461. The test method can measure thermal diffusivity values ranging from 10-7 to 10-3 m2/s from temperatures 75 to 2800 K.

  2. Mechanism of hot corrosion of IN-738

    NASA Technical Reports Server (NTRS)

    Meier, G. H.

    1982-01-01

    The Na2SO4 - induced hot corrosion of IN-738 in the temperature range 900 C to 1000 C is characterized by an initiation stage during which the corrosion rate is slow followed by a propagation stage during which the corrosion rate is markedly accelerated. In the second stage, corrosion is accelerated due essentially to a sulfidation/oxidation mechanism; in the third stage, the rate becomes catastrophic due to acid fluxing induced by an accumulation of refractory metal oxides (particularly MoO3) in the Na2SO4. The sequential stages in the corrosion process are described and a mechanism proposed. The influence of alloy microstructure on the corrosion mechanism is also discussed.

  3. Bacteriostatic conformal coating for electronic components

    NASA Technical Reports Server (NTRS)

    Bland, C.; Le Doux, F. N.

    1967-01-01

    Coating for electronic components used in space applications has bacteriostatic qualities capable of hindering bacterial reproduction, both vegetative and sporulative viable microorganisms. It exhibits high electrical resistivity, a low outgassing rate, and is capable of restraining electronic components when subjected to mechanical vibrations.

  4. Coating for components requiring hydrogen peroxide compatibility

    NASA Technical Reports Server (NTRS)

    Yousefiani, Ali (Inventor)

    2010-01-01

    The present invention provides a heretofore-unknown use for zirconium nitride as a hydrogen peroxide compatible protective coating that was discovered to be useful to protect components that catalyze the decomposition of hydrogen peroxide or corrode when exposed to hydrogen peroxide. A zirconium nitride coating of the invention may be applied to a variety of substrates (e.g., metals) using art-recognized techniques, such as plasma vapor deposition. The present invention further provides components and articles of manufacture having hydrogen peroxide compatibility, particularly components for use in aerospace and industrial manufacturing applications. The zirconium nitride barrier coating of the invention provides protection from corrosion by reaction with hydrogen peroxide, as well as prevention of hydrogen peroxide decomposition.

  5. Reevaluation of Bacitracin as a Spore Coat Component

    PubMed Central

    Marschke, C. K.; Bernlohr, R. W.

    1970-01-01

    Analysis of hydrolysates of highly purified spore coats revealed only small quantities of ornithine, a component of bacitracin. We conclude that the peptide, bacitracin, is not a significant component of spore coats. PMID:5437729

  6. Thermal barrier coatings for turbine components

    DOEpatents

    Subramanian, Ramesh; Sabol, Stephen M.; Goedjen, John G.; Sloan, Kelly M.; Vance, Steven J.

    2002-01-01

    A turbine component, such as a turbine blade having a metal substrate (22) is coated with a metal MCrAlY alloy layer (24) and then a thermal barrier layer (20) selected from LaAlO.sub.3, NdAlO.sub.3, La.sub.2 Hf.sub.2 O.sub.7, Dy.sub.3 Al.sub.5 O.sub.12, HO.sub.3 Al.sub.3 O.sub.12, ErAlO.sub.3, GdAlO.sub.3, Yb.sub.2 Ti.sub.2 O.sub.7, LaYbO.sub.3, Gd.sub.2 Hf.sub.2 O.sub.7 or Y.sub.3 Al.sub.5 O.sub.12.

  7. Plasma transferred arc repair welding of the nickel-base superalloy IN-738LC

    SciTech Connect

    Su, C.Y.; Chou, C.P.; Wu, B.C.; Lih, W.C.

    1997-10-01

    Plasma transferred arc welding (PTA) has been considered a promising process to restore worn areas of land-based gas turbine blades and vanes. The objective of this investigation was to study the effect of PTA welding on the repairing of IN-738LC superalloy components. Tensile tests were conducted on specimens welded with various combinations of parameters. Room temperature, 760 C, and 980 C were selected as tensile test temperatures. High-temperature phase transformed, during solidification, were identified by differential thermal analysis (DTA). The weld-pool shapes and microstructures of welded specimens prepared by various welding parameters were evaluated by optical metallography (OM), a scanning electron microscope (SEM) equipped with energy dispersive x-ray spectrometer (EDS), and microhardness testing. Results of this study showed that PTA welded specimens exhibited 96% nominal tensile strength of IN-738LC base materials. Specimen failure was observed predominantly in the base materials instead of in the heat-affected zone (HAZ) for gas tungsten arc weld (GTAW) repair weldments. IN-738LC is considered susceptible to weld cracking during fusion welding; however, using a low-input repair welding process (PTA), cracking susceptibility could be minimized by the optimized welding parameters.

  8. Thermal barrier coatings for heat engine components

    NASA Technical Reports Server (NTRS)

    Levine, S. R.; Miller, R. A.; Hodge, P. E.

    1980-01-01

    A comprehensive NASA-Lewis program of coating development for aircraft gas turbine blades and vanes is presented. Improved ceramic layer compositions are investigated, along the MCrAlY bond films and the methods of uniform deposition of the coatings; the thermomechanical and fuel impurity tolerance limits of the coatings are being studied. Materials include the ZrO2-Y2O3/NiCrAlY system; the effects of the bond coat and zirconia composition on coating life and Mach 1 burner rig test results are discussed. It is concluded that Diesel engines can also utilize thermal barrier coatings; they have been used successfully on piston crowns and exhaust valves of shipboard engines to combat lower grade fuel combustion corrosion.

  9. Application of advanced coating techniques to rocket engine components

    NASA Technical Reports Server (NTRS)

    Verma, S. K.

    1988-01-01

    The materials problem in the space shuttle main engine (SSME) is reviewed. Potential coatings and the method of their application for improved life of SSME components are discussed. A number of advanced coatings for turbine blade components and disks are being developed and tested in a multispecimen thermal fatigue fluidized bed facility at IIT Research Institute. This facility is capable of producing severe strains of the degree present in blades and disk components of the SSME. The potential coating systems and current efforts at IITRI being taken for life extension of the SSME components are summarized.

  10. Thick thermal barrier coatings for diesel components

    NASA Technical Reports Server (NTRS)

    Yonushonis, T. M.

    1991-01-01

    An engineered thick thermal barrier coating consisting of multiple layers of zirconia and CoCrAlY with a zirconia top layer and having a system thermal conductance less than 410 w/m(exp 2)K exceeded the 100 hour engine durability goals set forth in this program. The thermal barrier coatings were intact at the test conclusion. Back to back single cylinder research engine tests were conducted with watercooled, metal hardware and oil-cooled, thermal barrier coating insulated hardware to determine apparent heat release and fuel economy. Apparent heat release data revealed that the insulated engine had a shorter ignition delay and a longer combustion duration than the metal engine. The insulated engine fuel economy was approximately two percent worse on average for this series of tests. There was no attempt to optimize engine efficiency of the insulated engine by modifying the engine timing, coating, or other techniques.

  11. Moisture-resistant coatings for optical components

    NASA Technical Reports Server (NTRS)

    Hollahan, J. R.; Wydeven, T.; Johnson, C. C.

    1973-01-01

    Plasma polymerization technique is used to apply thin, adherent, hydrophobic coatings from chlorotrifluoroethylene monomer. Apparently much of the chlorine contained in original monomer is lost during polymerization, and characteristic C-Cl absorption in infrared region is essentially absent.

  12. Low VOC, Plural Component Spray (PCS) Coatings Program

    DTIC Science & Technology

    2009-05-07

    Continuous Application Method Plural Component Spray Benefits • Automated proportioning • Precision mixing • Utilizes HVLP spray guns • Accommodates...255 - 3541 roddy.keish@wpafb.af.mil Birthplace, Home and Future of Aerospace Low VOC, Plural Component Spray (PCS) Coatings Program 7 May 2009 Report...2009 2. REPORT TYPE 3. DATES COVERED 00-00-2009 to 00-00-2009 4. TITLE AND SUBTITLE Low VOC, Plural Component Spray (PCS) Coatings Program 5a

  13. Two-layer thermal barrier coating for high temperature components

    NASA Technical Reports Server (NTRS)

    Stecura, S.

    1977-01-01

    A simple two-layer plasma-sprayed thermal barrier coating system was developed which has the potential for protecting high temperature air-cooled gas turbine components. Of the initially examined coatings, the most promising system is an Ni-16Cr-6Al-0.6Y (in wt%) bond coating (about 0.005 to 0.010 cm thick) and a ZrO2-12Y2O3 (in wt%) thermal barrier coating (about 0.025 to 0.064 cm thick). This thermal barrier substantially lowered the metal temperature of the air-cooled airfoil. The coating withstood 3200 cycles (80 s at 1280 C surface temperature) and 275 cycles (1 hr at 1490 C surface temperature) without cracking or spalling. No separation of the thermal barrier from the bond coating or the bond coating from the substrate was observed.

  14. Coating power RF components with TiN

    SciTech Connect

    Kuchnir, M.; Hahn, E.

    1995-03-01

    A facility for coating RF power components with thin films of Ti and/or TiN has been in operation for some time at Fermilab supporting the Accelerator Division RF development work and the TESLA program. It has been experimentally verified that such coatings improve the performance of these components as far as withstanding higher electric fields. This is attributed to a reduction in the secondary electron emission coefficient of the surfaces when coated with a thin film containing titanium. The purpose of this Technical Memorandum is to describe the facility and the procedure used.

  15. Increased Reliability of Gas Turbine Components by Robust Coatings Manufacturing

    NASA Astrophysics Data System (ADS)

    Sharma, A.; Dudykevych, T.; Sansom, D.; Subramanian, R.

    2017-08-01

    The expanding operational windows of the advanced gas turbine components demand increasing performance capability from protective coating systems. This demand has led to the development of novel multi-functional, multi-materials coating system architectures over the last years. In addition, the increasing dependency of components exposed to extreme environment on protective coatings results in more severe penalties, in case of a coating system failure. This emphasizes that reliability and consistency of protective coating systems are equally important to their superior performance. By means of examples, this paper describes the effects of scatter in the material properties resulting from manufacturing variations on coating life predictions. A strong foundation in process-property-performance correlations as well as regular monitoring and control of the coating process is essential for robust and well-controlled coating process. Proprietary and/or commercially available diagnostic tools can help in achieving these goals, but their usage in industrial setting is still limited. Various key contributors to process variability are briefly discussed along with the limitations of existing process and product control methods. Other aspects that are important for product reliability and consistency in serial manufacturing as well as advanced testing methodologies to simplify and enhance product inspection and improve objectivity are briefly described.

  16. Increased Reliability of Gas Turbine Components by Robust Coatings Manufacturing

    NASA Astrophysics Data System (ADS)

    Sharma, A.; Dudykevych, T.; Sansom, D.; Subramanian, R.

    2017-06-01

    The expanding operational windows of the advanced gas turbine components demand increasing performance capability from protective coating systems. This demand has led to the development of novel multi-functional, multi-materials coating system architectures over the last years. In addition, the increasing dependency of components exposed to extreme environment on protective coatings results in more severe penalties, in case of a coating system failure. This emphasizes that reliability and consistency of protective coating systems are equally important to their superior performance. By means of examples, this paper describes the effects of scatter in the material properties resulting from manufacturing variations on coating life predictions. A strong foundation in process-property-performance correlations as well as regular monitoring and control of the coating process is essential for robust and well-controlled coating process. Proprietary and/or commercially available diagnostic tools can help in achieving these goals, but their usage in industrial setting is still limited. Various key contributors to process variability are briefly discussed along with the limitations of existing process and product control methods. Other aspects that are important for product reliability and consistency in serial manufacturing as well as advanced testing methodologies to simplify and enhance product inspection and improve objectivity are briefly described.

  17. Wear Resistant Nanostructured Multi-component Coatings

    NASA Astrophysics Data System (ADS)

    Urbahs, A.; Urbaha, M.; Savkovs, K.; Bogdanova, S.

    The authors offer the restoration technology of precision pair parts - valves, plungers and injectors of vehicle fuel pumps. The technology stipulates the creation of a special restoring wear-resistant coating on the basis of Ti-Al-N (titanium-aluminum-nitrogen) deposited by ion-plasma sputtering. The possibility of combining the methods of electric arc and magnetron sputtering, which arose as a result of the modification of the installation, makes it possible to partially reduce the drawbacks of both methods by simultaneously using their basic advantages. This technique, in particular, gave the opportunity to reduce the drop phase without reducing the efficiency of ion bombardment. In addition, the spectrum of materials being sputtered has been expanded and their quality has been improved.

  18. DIFFUSION COATINGS FOR CORROSION RESISTANT COMPONENTS IN COAL GASIFICATION SYSTEMS

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2005-01-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve is resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this reporting period we coated coupons of selected alloy steels with diffusion coatings of Cr and Al, as well as with titanium and tantalum nitrides. The coated samples were analyzed for their surface composition. In several instances, the samples were also cut to determine the depth profile of the coating. Several of the early runs did not yield uniform or deep enough coatings and hence a significant portion of the effort in this period was devoted fixing the problems with our fluidized bed reactor. Before the end of the quarter we had prepared a number of samples, many of them in duplicates, and sent one set to Wabash River Energy Laboratory for them to install in their gasifier. The gasifier was undergoing a scheduled maintenance and thus presented an opportunity to place some of our coupons in the stream of an operating gasifier. The samples submitted included coated and uncoated pairs of different alloys.

  19. DIFFUSION COATINGS FOR CORROSION RESISTANT COMPONENTS IN COAL GASIFICATION SYSTEMS

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Angel Sanjurjo

    2004-05-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve is resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. A review of the literature indicated that the Fe- and Ni-based high-temperature alloys are susceptible to sulfidation attack unless they are fortified with high levels of Cr, Al, and Si. To impart corrosion resistance, these elements need not be in the bulk of the alloy and need only be present at the surface layers. We selected diffusion coatings of Cr and Al, and surface coatings of Si and Ti for the preliminary testing. These coatings will be applied using the fluidized bed chemical vapor deposition technique developed at SRI which is rapid and relatively inexpensive. We have procured coupons of typical alloys used in a gasifier. These coupons will be coated with Cr, Al, Si, and Ti. The samples will be tested in a bench-scale reactor using simulated coal gas compositions. In addition, we will be sending coated samples for insertion in the gas stream of the coal gasifier.

  20. Laser drilling of thermal barrier coated jet-engine components

    NASA Astrophysics Data System (ADS)

    Sezer, H. K.

    Aero engine hot end components are often covered with ceramic Thermal Barrier Coatings (TBCs). Laser drilling in the TBC coated components can be a source of service life TBC degradation and spallation. The present study aims to understand the mechanisms of TBC delamination and develop techniques to drill holes without damaging the TBC, Nimonic 263 workpieces coated with TBC are used in the experiments. Microwave non-destructive testing (NDT) is employed to monitor the integrity of the coating /substrate interfaces of the post-laser drilled materials. A numerical modelling technique is used to investigate the role of melt ejection on TBC delamination. The model accounts for the vapour and the assist gas flow effects in the process. Broadly, melt ejection induced mechanical stresses for the TBC coating / bond coating and thermal effects for the bond coating / substrate interfaces are found the key delamination mechanisms. Experiments are carried out to validate the findings from the model. Various techniques that enable laser drilling without damaging the TBC are demonstrated. Twin jet assisted acute angle laser drilling is one successful technique that has been analysed using the melt ejection simulation. Optimisation of the twin jet assisted acute angle laser drilling process parameters is carried out using Design of Experiments (DoE) and statistical modelling approaches. Finally, an industrial case study to develop a high speed, high quality laser drilling system for combustor cans is described. Holes are drilled by percussion and trepan drilling in TBC coated and uncoated Haynes 230 workpieces. The production rate of percussion drilling is significantly higher than the trepan drilling, however metallurgical hole quality and reproducibility is poor. A number of process parameters are investigated to improve these characteristics. Gas type and gas pressure effects on various characteristics of the inclined laser drilled holes are investigated through theoretical

  1. Osseointegration in porous coated knee arthroplasty. The influence of component coating type in sheep.

    PubMed

    Bellemans, J

    1999-10-01

    Although cementless knee arthroplasty is a commonly performed procedure, to date very little was known about the process of osseointegration of knee arthroplasty components. Using a knee prosthesis that was specially designed for the sheep stifle joint, this process of osseointegration could be studied in vivo, together with its effects on clinical and functional performance, its influence on mechanical fixation, and its influence on component stability or migration over time. Additionally, the osseointegration capacity of a newly developed cast mesh porous coating could be examined. The rationale for this newly developed coating was to provide a surface texture with theoretically superior osseointegration capacity, by offering a larger and better controlled pore size, with higher ingrowth area compared to conventional bead type coatings. In summary, the conclusions that are drawn from this work are the following: 1. The degree of osseointegration of knee arthroplasty components is not correlated with clinical and functional performance. Knee arthroplasty components with fibrous integration can function as well as osseointegrated components at least during the first years after implantation. This explains the occasional reports in the literature of post mortem retrieved, well functioning knee arthroplasty components, with purely fibrous integration on histomorphometric analysis. 2. Fibrous integration of tibial knee arthroplasty components, however, leads to less mechanical fixation strength of these components. Osseointegrated components are much more strongly fixed to the underlying bone. This difference in mechanical fixation strength is detectable under physiologic loads. 3. Fibrous integration of tibial knee arthroplasty components leads to increased migration, becoming apparent after 1 year with radiostereometric analysis (RSA). Osseointegrated components are significantly more stable over time. 4. Fibrous integration is less desirable, since it leads to

  2. Scale formation on the Ni-base superalloys IN 939 and IN 738 LC

    SciTech Connect

    Litz, J.; Rahmel, A.; Schorr, M. ); Weiss, J. )

    1989-10-01

    The scales formed on the superalloys IN 939 and IN 738 LC at 700, 900, and 1,100{degree}C in air have been investigated by optical, microprobe analysis and x-ray diffraction measurements. Both alloys form very similar scales. The main components are an outer TiO{sub 2} layer, an intermediate Cr{sub 2}O{sub 3} layer with dissolved Ti, and an inner layer of (Ti, Nb, Ta)O{sub 2} with rutile structure. Beneath the scale an internal corrosion zone is formed that contained Al{sub 2}O{sub 3} directly beneath the external scale and TiN further into the substrate.

  3. Turbine repair process, repaired coating, and repaired turbine component

    DOEpatents

    Das, Rupak; Delvaux, John McConnell; Garcia-Crespo, Andres Jose

    2015-11-03

    A turbine repair process, a repaired coating, and a repaired turbine component are disclosed. The turbine repair process includes providing a turbine component having a higher-pressure region and a lower-pressure region, introducing particles into the higher-pressure region, and at least partially repairing an opening between the higher-pressure region and the lower-pressure region with at least one of the particles to form a repaired turbine component. The repaired coating includes a silicon material, a ceramic matrix composite material, and a repaired region having the silicon material deposited on and surrounded by the ceramic matrix composite material. The repaired turbine component a ceramic matrix composite layer and a repaired region having silicon material deposited on and surrounded by the ceramic matrix composite material.

  4. Case history advanced coatings for water treatment plant components

    SciTech Connect

    Stephenson, L.D.; Kumar, A.

    2008-12-15

    Components of water treatment plants (WTPs) are susceptible to corrosion from constant immersion in water. A case history of corrosion and proximity to chlorine problems and their treatment at an Army WTP is presented. Solutions included using high micro-silica restoration mortar and advanced coal tar epoxy coatings.

  5. Hot corrosion studies of four nickel-base superalloys - B-1900, NASA-TRW VIA, 713C and IN738

    NASA Technical Reports Server (NTRS)

    Fryburg, G. C.; Kohl, F. J.; Stearns, C. A.

    1976-01-01

    The susceptibility to hot corrosion of four nickel-base superalloys has been studied at 900 and 1000 C in one atmosphere of slowly flowing oxygen. Hot corrosion was induced by coating the samples with known doses of Na2SO4 and oxidizing the coated samples isothermally on a sensitive microbalance. In order of decending susceptibility to hot corrosion, these alloys were ranked: B-1900, 713C, NASA-TRW VIA, IN738. This order corresponds to the order of decreasing molybdenum content of the alloys. Chemical evidence for B-1900 indicates that hot corrosion is instigated by acid fluxing of the protective Al2O3 coating by MoO3.

  6. Hot corrosion studies of four nickel-base superalloys - B-1900, NASA-TRW VIA, 713C and IN738

    NASA Technical Reports Server (NTRS)

    Fryburg, G. C.; Kohl, F. J.; Stearns, C. A.

    1976-01-01

    The susceptibility to hot corrosion of four nickel-base superalloys has been studied at 900 and 1000 C in one atmosphere of slowly flowing oxygen. Hot corrosion was induced by coating the samples with known doses of Na2SO4 and oxidizing the coated samples isothermally on a sensitive microbalance. In order of decending susceptibility to hot corrosion, these alloys were ranked: B-1900, 713C, NASA-TRW VIA, IN738. This order corresponds to the order of decreasing molybdenum content of the alloys. Chemical evidence for B-1900 indicates that hot corrosion is instigated by acid fluxing of the protective Al2O3 coating by MoO3.

  7. Hot corrosion studies of four nickel-base superalloys: B-1900, NASA-TRW VIA, 713C and IN738

    NASA Technical Reports Server (NTRS)

    Fryburg, G. C.; Kohl, F. J.; Stearns, C. A.

    1976-01-01

    The susceptibility to hot corrosion of four nickel base superalloys has been studied at 900 deg and 1000 deg C in one atmosphere of slowly flowing oxygen. Hot corrosion was induced by coating the samples with known doses of NaSO4 and oxidizing the coated samples isothermally on a sensitive microbalance. In general, the order of susceptibility found was: B-1900 is greater than 713C is greater than NASA-TRW VIA and is greater than IN738. This order corresponds to the order of decreasing molybdenum content of the alloys. Chemical evidence for B-1900 indicates that hot corrosion is instigated by acid fluxing of the protective Al2O3 coating by MoO3.

  8. Polarized BRDF for coatings based on three-component assumption

    NASA Astrophysics Data System (ADS)

    Liu, Hong; Zhu, Jingping; Wang, Kai; Xu, Rong

    2017-02-01

    A pBRDF(polarized bidirectional reflection distribution function) model for coatings is given based on three-component reflection assumption in order to improve the polarized scattering simulation capability for space objects. In this model, the specular reflection is given based on microfacet theory, the multiple reflection and volume scattering are given separately according to experimental results. The polarization of specular reflection is considered from Fresnel's law, and both multiple reflection and volume scattering are assumed depolarized. Simulation and measurement results of two satellite coating samples SR107 and S781 are given to validate that the pBRDF modeling accuracy can be significantly improved by the three-component model given in this paper.

  9. Multi-source/component spray coating for polymer solar cells.

    PubMed

    Chen, Li-Min; Hong, Ziruo; Kwan, Wei Lek; Lu, Cheng-Hsueh; Lai, Yi-Feng; Lei, Bao; Liu, Chuan-Pu; Yang, Yang

    2010-08-24

    A multi-source/component spray coating process to fabricate the photoactive layers in polymer solar cells is demonstrated. Well-defined domains consisting of polymer:fullerene heterojunctions are constructed in ambient conditions using an alternating spray deposition method. This approach preserves the integrity of the layer morphology while forming an interpenetrating donor (D)/acceptor (A) network to facilitate charge transport. The formation of multi-component films without the prerequisite of a common solvent overcomes the limitations in conventional solution processes for polymer solar cells and enables us to process a wide spectrum of materials. Polymer solar cells based on poly(3-hexylthiophene):[6,6]-phenyl C(61) butyric acid methyl ester spray-coated using this alternating deposition method deliver a power conversion efficiency of 2.8%, which is comparable to their blend solution counterparts. More importantly, this approach offers the versatility to independently select the optimal solvents for the donor and acceptor materials that will deliver well-ordered nanodomains. This method also allows the direct stacking of multiple photoactive polymers with controllable absorption in a tandem structure even without an interconnecting junction layer. The introduction of multiple photoactive materials through multisource/component spray coating offers structural flexibility and tenability of the photoresponse for future polymer solar cell applications.

  10. DIFFUSION COATINGS FOR CORROSION RESISTANT COMPONENTS IN COAL GASIFICATION SYSTEMS

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Angel Sanjurjo

    2004-05-01

    Heat-exchangers, filters, turbines, and other components in integrated coal gasification combined cycle system must withstand demanding conditions of high temperatures and pressure differentials. Under the highly sulfiding conditions of the high temperature coal gas, the performance of components degrade significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve is resistance to such sulfidation attack and decrease capital and operating costs. A review of the literature indicates that the corrosion reaction is the competition between oxidation and sulfidation reactions. The Fe- and Ni-based high-temperature alloys are susceptible to sulfidation attack unless they are fortified with high levels of Cr, Al, and Si. To impart corrosion resistance, these elements need not be in the bulk of the alloy and need only be present at the surface layers.

  11. Development of wear resistant ceramic coatings for diesel engine components

    SciTech Connect

    Haselkorn, M.H. )

    1992-04-01

    Improved fuel economy and a reduction of emissions can be achieved by insulation of the combustion chamber components to reduce heat rejection. However, insulating the combustion chamber components will also increase the operating temperature of the piston ring/cylinder liner interface from approximately 150{degree}C to over 300{degree}C. Existing ring/liner materials can not withstand these higher operating temperatures and for this reason, new materials need to be developed for this critical tribological interface. The overall goal of this program is the development of piston ring/cylinder liner material pairs which would be able to provide the required friction and wear properties at these more severe operating conditions. More specifically, this program first selected, and then evaluated, potential d/wear resistant coatings which could be applied to either piston rings an or cylinder liners and provide, at 350{degree}C under lubricated conditions, coefficients of friction below 0.1 and wear rates of less than 25 {times} lO{sup {minus}6} mm/hour. The processes selected for applying the candidate wear resistant coatings to piston rings and/or cylinder liners were plasma spraying, chemical vapor, physical vapor and low temperature arc vapor deposition techniques as well as enameling techniques.

  12. Graphene as a Coating for Plasma Facing Components

    NASA Astrophysics Data System (ADS)

    Navarro, Marcos; Rojas, Richard; Kulcisnki, Gerald; Lagally, Max; Santarius, John

    2016-10-01

    Graphene has been a source of interest for multiple applications because of its unusual electronic and mechanical properties. A number of experimental studies have established that defect-free graphene is an excellent chemical-barrier material, but there have been no reports of graphene proposed as a protective coating against ion and/or neutral interactions with material surfaces. In the presence of such irradiation, plasma facing components (PFC's) tend to develop ``fuzz/grass'' structures that lead to the sputtering of wall material, diminishing the lifetime of the PFC's and plasma performance. We have shown that graphene can reduce or eliminate changes on surface morphology due to energetic helium. In the case of graphene-covered tungsten, our results show that, compared to the uncovered W, graphene suppresses these morphologies that form on the surface of hot W. Using Raman spectroscopy as a diagnostic, the graphene coating shows little sign of damage after being irradiated, indicating that there is little to no sputtering of carbon impurities from the surface. We have also determined that the mass losses in W have been reduced significantly. Both decreases in impurities can lead to an improved plasma performance and longer lifetimes for PFC's. This work has been supported by GERS and TEAM-Science at the UW-Madison.

  13. Extensively coated cementless femoral components in revision hip arthroplasty.

    PubMed

    Greidanus, N; Antoniou, J; Paprosky, W

    2000-01-01

    A septic loosening and osteolysis can compromise the available host bone in patients requiring revision hip arthroplasty. Secure fixation of revision femoral components may not be possible if reliant only on proximal femoral bone for biologic fixation or cement interdigitation. The challenge for the revision arthroplasty surgeon is to find the best method to secure the implant in a femur with deficient bone proximally that will provide stability for load bearing and motion. In addition to providing stability, the implant must be durable and maintain long-term fixation. With over 16 years of experience with fully porous coated femoral revision implants, we have found that maximizing prosthetic-bone fit in the proximal femoral diaphyseal bone provides reliable long-term fixation in the majority of femoral revision cases.

  14. Extensively Coated Cementless Femoral Components in Revision Hip Arthroplasty.

    PubMed

    Greidanus, Nelson; Antoniou, John; Paprosky, Wayne

    2000-10-01

    A septic loosening and osteolysis can compromise the available host bone in patients requiring revision hip arthroplasty. Secure fixation of revision femoral components may not be possible if reliant only on proximal femoral bone for biologic fixation or cement interdigitation. The challenge for the revision arthroplasty surgeon is to find the best method to secure the implant in a femur with deficient bone proximally that will provide stability for load bearing and motion. In addition to providing stability, the implant must be durable and maintain long-term fixation. With over 16 years of experience with fully porous coated femoral revision implants, we have found that maximizing prosthetic-bone fit in the proximal femoral diaphyseal bone provides reliable long-term fixation in the majority of femoral revision cases.

  15. The WEST project: validation program for WEST tungsten coated plasma facing components

    NASA Astrophysics Data System (ADS)

    Richou, M.; Missirlian, M.; Tsitrone, E.; Bucalossi, J.; Desgranges, C.; Firdaouss, M.; Guilhem, D.; Greuner, H.; Hernandez, C.; Lipa, M.; Pintsuk, G.; Samaille, F.

    2016-02-01

    The W—for tungsten—Environment in Steady-state Tokamak (WEST) project is based on an upgrade of the Tore Supra tokamak from a carbon limiter to an X-point divertor device. A new set of actively cooled tungsten coated plasma facing components will cover a part of the vessel to provide a fully metallic environment. This paper deals with the validation program performed for tungsten coatings (≥15 μm) on a CuCrZr substrate. The first step was dedicated to the qualification under high heat flux tests of the coating on small inertially cooled samples. To study the thermal behavior and the non-uniformity, the second step was dedicated to the validation of the coating on large inertially cooled samples with geometry and shape (540 × 120 mm) representative of the WEST coated components. The last step was dedicated to the optimization of the coating and to the high heat flux tests up to 10.5 MW m-2 on relevant coated actively cooled prototypes. Non-uniformity and thickness of the coating (15 and 30 μm) correspond to specifications. As no delamination was observed, coatings of 15 and 30 μm were qualified with regard to their application on WEST coated components. In order to decrease the risk of coating delamination under thermal loading, it was decided to cover the upper divertor and baffle targets with the thinnest coating option of 15 μm.

  16. Oxidation resistant coatings for ceramic matrix composite components

    SciTech Connect

    Vaubert, V.M.; Stinton, D.P.; Hirschfeld, D.A.

    1998-11-01

    Corrosion resistant Ca{sub 0.6}Mg{sub 0.4}Zr{sub 4}(PO{sub 4}){sub 6} (CMZP) and Ca{sub 0.5}Sr{sub 0.5}Zr{sub 4}(PO{sub 4}){sub 6} (CS-50) coatings for fiber-reinforced SiC-matrix composite heat exchanger tubes have been developed. Aqueous slurries of both oxides were prepared with high solids loading. One coating process consisted of dipping the samples in a slip. A tape casting process has also been created that produced relatively thin and dense coatings covering a large area. A processing technique was developed, utilizing a pre-sintering step, which produced coatings with minimal cracking.

  17. Functionally Graded Hydroxyapatite Coatings Doped with Antibacterial Components

    SciTech Connect

    Bai, Xiao; More, Karren Leslie; Rouleau, Christopher M; Rabiei, Afsaneh

    2010-01-01

    A series of functionally graded hydroxyapatite (FGHA) coatings incorporated with various percentages of silver were deposited on titanium substrates using ion beam assisted deposition (IBAD). The analysis of the coating s cross-section using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM), equipped with energy dispersive X-ray spectroscopy (EDS), has shown a decreased crystallinity as well as a distribution of nano scale (10 ~ 50nm) silver particles from the coating/substrate interface to top surface. Both X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR) results revealed the presence of hydroxyapatite within the coatings. The amount of Ag (wt. %) on the outer surface of the FGHA, as determined from X-ray photoelectron spectroscopy (XPS), ranged from 1.09 ~ 6.59, which was about half of the average Ag wt. % incorporated in the entire coating. Average adhesion strengths evaluated by pull-off tests were in the range of 83 6 - 88 3 MPa, which is comparable to 85 MPa for FGHA without silver. Further optical observations of failed areas illustrated that the dominant failure mechanism was epoxy failure and FGHA coating delamination was not observed.

  18. Replacement of Chromium Electroplating on Gas Turbine Engine Components using Thermal Spray Coatings

    DTIC Science & Technology

    2006-05-01

    Chromium Electroplating on Gas Turbine Engine Components Using Thermal Spray Coatings May 2006 Report Documentation Page Form ApprovedOMB No. 0704-0188...2006 4. TITLE AND SUBTITLE Replacement of Chromium Electroplating on Gas Turbine Engine Components Using Thermal Spray Coatings 5a. CONTRACT...Security Review, Rm. 2C157, Pentagon 1. DOCUMENT DESCRIPTION a. TYPE b. TITLE Replacement of Chromium Electroplating on Gas TUibine Engine Components

  19. Metallized coatings for corrosion control of Naval ship structures and components

    NASA Technical Reports Server (NTRS)

    1983-01-01

    In attempting to improve corrosion control, the U.S. Navy has undertaken a program of coating corrosion-susceptible shipboard components with thermally sprayed aluminum. In this report the program is reviewed in depth, including examination of processes, process controls, the nature and properties of the coatings, nondestructive examination, and possible hazards to personnel. The performance of alternative metallic coating materials is also discussed. It is concluded that thermally sprayed aluminum can provide effective long-term protection against corrosion, thereby obviating the need for chipping of rust and repainting by ship personnel. Such coatings are providing excellent protection to below-deck components such as steam valves, but improvements are needed to realize the full potential of coatings for above-deck service. Several recommendations are made regarding processes, materials, and research and development aimed at upgrading further the performance of these coatings.

  20. Sublimation TiN Coating of RF Power Components

    NASA Astrophysics Data System (ADS)

    Lorkiewicz, J.; Kula, J.; Pszona, S.; Sobczak, J.; Bilinski, A.

    2008-03-01

    Titanium evaporation in a reactive atmosphere of ammonia has been chosen to deposit thin (up to 10 nm) protective surface layers containing titanium nitride and titanium oxinitrides which suppress secondary electron emission. The coating procedure, applied by the author in DESY (Hamburg) for TESLA couplers anti-multipactor protection, has been recently implemented in The Andrzej Soltan Institute for Nuclear Studies (IPJ) where a new coating device is used, equipped with a special titanium sublimation setup in a 100 1 vacuum chamber. Several arrays of cylindrical and coaxial RF coupler windows have been coated so far after optimizing the processing parameters. A check of the obtained surface layers ability to attenuate secondary electron emission has been performed; measurements of the secondary electron yield from TiN layers deposited on alumina samples were done in IPJ on as-delivered coated samples, then after vacuum bake-out and finally after additional electron bombardment of their surfaces. Also chemical composition of the surface layers has been studied using XPS in the Institute of Physical Chemistry (IChF).

  1. Metallized Coatings for Corrosion Control of Naval Ship Structures and Components.

    DTIC Science & Technology

    1983-02-01

    susceptible shipboard components with thermally sprayed aluminum. In this report the program is reviewed in depth, including examination of processes...Navy has undertaken a program of coating corrosion-susceptible shipboard components with thermally sprayed aluminum. In this report the program is... shipboard tests were conducted with wire-sprayed aluminum (WSA) coatings using oxyacetylene torches to melt, atomize, and spray-deposit aluminum

  2. Fabrication of strain-isolated ceramic coated combustor components

    NASA Technical Reports Server (NTRS)

    Rutter, S.

    1985-01-01

    The use of strain-isolated ceramic coated material to produce an AGT1500 combustor scroll-shaped transition duct which requires no air for film cooling is investigated. The scroll receives the exhaust of the can-style combustor liner and turns it into the annular inlet of the high pressure gas producer turbine nozzle. Strain-isolation of plasma sprayed thermal barrier coating is achieved by placing a compliant pad between the structural base metal and the ceramic coating. The compliant pad is brazed to the metal structure. In order to achieve a good braze bond, the strain-isolating compliant pad and base metal must be closely matched in shape and tightly fixtured for joining. The complex geometry of the AGT1500 scroll makes it impractical to attack pads to the supporting structure in its finished shape. Instead the pads are brazed to flat stock and post-formed into scroll sections. While test samples were successfully post-formed, plasma sprayed, and subjected to cyclic heating, the forming of full scale parts by normal methods resulted in tearing of the Hastelloy-X base metal because of embrittlement by the braze material. Several solutions were explored which finally resulted in the successful forming of full scale scroll parts.

  3. Advanced Environmental Barrier Coating Development for SiC-SiC Ceramic Matrix Composite Components

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Harder, Bryan; Bhatt, Ramakrishna; Kiser, Doug; Wiesner, Valerie L.

    2016-01-01

    This presentation reviews the NASA advanced environmental barrier coating (EBC) system development for SiCSiC Ceramic Matrix Composite (CMC) components for next generation turbine engines. The emphasis has been placed on the current design challenges of the 2700F environmental barrier coatings; coating processing and integration with SiCSiC CMCs and component systems; and performance evaluation and demonstration of EBC-CMC systems. This presentation also highlights the EBC-CMC system temperature capability and durability improvements through advanced compositions and architecture designs, as shown in recent simulated engine high heat flux, combustion environment, in conjunction with mechanical creep and fatigue loading testing conditions.

  4. Effects of vacuum treatment on the formation of TGO in YSZ-TBC on IN738LC — An interpretation of EDX line-scan data

    NASA Astrophysics Data System (ADS)

    Kim, Min Tae; Jung, Yong Chan; Lee, Tae Hee

    2014-09-01

    This study examined the effects of vacuum heat-treatment on the growth of oxide (thermally grown oxide, TGO) between the ceramic top coat (yttria-stabilized zirconia, YSZ) and the metallic bond coat (NiCrAlY) of a thermal barrier coating (TBC). For the investigation, IN738LC coupons coated with a TBC were heat-treated in vacuum and/or isothermally oxidized at 1200 °C and then microscopically analyzed using SEM and EDX. The introduction of heat treatment in vacuum before isothermal oxidation resulted in a reduction of the TGO thickness and the number of interface cracks around the TGO layers. These TGO layers were further analyzed using EDX line scan data in terms of the dependence of the EDX Al intensity on the O intensity. The analysis showed that the TGO layers in the coupons only oxidized in air were divided into two sub-layers with respect to the gradient of the Al intensity on the O intensity. The pre-treatment in vacuum nullified this division and reduced cracks at the interfaces. The effects of the treatment in vacuum on the behavior of TGO and TBCs were analyzed and compared with the data obtained for a TBC-coated turbine blade serviced for a land-based heavy duty gas turbine.

  5. Apparatus for determining past-service conditions and remaining life of thermal barrier coatings and components having such coatings

    DOEpatents

    Srivastava, Alok Mani; Setlur, Anant Achyut; Comanzo, Holly Ann; Devitt, John William; Ruud, James Anthony; Brewer, Luke Nathaniel

    2004-05-04

    An apparatus for determining past-service conditions and/or remaining useful life of a component of a combustion engine and/or a thermal barrier coating ("TBC") of the component comprises a radiation source that provides the exciting radiation to the TBC to excite a photoluminescent ("PL") material contained therein, a radiation detector for detecting radiation emitted by the PL material, and means for relating a characteristic of an emission spectrum of the PL material to the amount of a crystalline phase in the TBC, thereby inferring the past-service conditions or the remaining useful life of the component or the TBC.

  6. High Temperature Protective Coatings for Aero Engine Gas Turbine Components (Revetements Protecteurs Hautes Temperatures pour Composants de Turbines a Gaz Aeronautique).

    DTIC Science & Technology

    1986-09-01

    6 - Recently Pilsner(34) has observed interdiffusion in a diffusion couple consisting of a plasma sprayed NiCrAIZr coating on a MAR - M247 ...Mo in IN713C and 10% \\V in MAR -M246), acidic fluxing of protective oxide can take place, compounding the problem of hot corrosion. Short term...trend followed by alloys like IN713C, MAR -M246 and IN738C in this order, at temperatures ranging from 1373K to 1473K(6). Oxygen active elements (eg. Y

  7. Hot Deformation Processing Map and Microstructural Evaluation of the Ni-Based Superalloy IN-738LC

    NASA Astrophysics Data System (ADS)

    Sajjadi, S. A.; Chaichi, A.; Ezatpour, H. R.; Maghsoudlou, A.; Kalaie, M. A.

    2016-04-01

    Hot deformation behavior of the Ni-based superalloy IN-738LC was investigated by means of hot compression tests over the temperature range of 1000-1200 °C and strain rate range of 0.01-1 s-1. The obtained peak flow stresses were related to strain rate and temperature through the hyperbolic sine equation with activation energy of 950 kJ/mol. Dynamic material model was used to obtain the processing map of IN-738LC. Analysis of the microstructure was carried out in order to study each domain's characteristic represented by the processing map. The results showed that dynamic recrystallization occurs in the temperature range of 1150-1200 °C and strain rate of 0.1 s-1 with the maximum power dissipation efficiency of 35%. The unstable domain was exhibited in the temperature range of 1000-1200 °C and strain rate of 1 s-1 on the occurrence of severe deformation bands and grain boundary cracking.

  8. Furnace Cyclic Oxidation Behavior of Multi-Component Low Conductivity Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Nesbitt, James A.; Barrett, Charles A.; McCue, Terry R.; Miller, Robert A.

    2004-01-01

    Ceramic thermal barrier coatings will play an increasingly important role in advanced gas turbine engines because of their ability to further increase engine operating temperatures and reduce cooling, thus helping achieve future engine low emission, high efficiency and improved reliability goals. Advanced multi-component zirconia-based thermal barrier coatings are being developed using an oxide defect clustering design approach to achieve the required coating low thermal conductivity and high temperature stability. Although the new composition coatings were not yet optimized for cyclic durability, an initial durability screening of the candidate coating materials was conducted using conventional furnace cyclic oxidation tests. In this paper, furnace cyclic oxidation behavior of plasma-sprayed zirconia-based defect cluster thermal barrier coatings was investigated at 1163 C using 45 min hot cycles. The ceramic coating failure mechanisms were studied using scanning electron microscopy (SEM) combined with X-ray diffraction (XRD) phase analysis after the furnace tests. The coating cyclic lifetime is also discussed in relation to coating processing, phase structures, dopant concentration, and other thermo-physical properties.

  9. High Pressure Burner Rig Testing of Advanced Environmental Barrier Coatings for Si3N4 Turbine Components

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Fox, Dennis S.; Pastel, Robert T.

    2007-01-01

    Advanced thermal and environmental barrier coatings are being developed for Si3N4 components for turbine engine propulsion applications. High pressure burner rig testing was used to evaluate the coating system performance and durability. Test results demonstrated the feasibility and durability of the coating component systems under the simulated engine environments.

  10. FUNCTIONALLY GRADED ALUMINA/MULLITE COATINGS FOR PROTECTION OF SILICON CARBIDE CERAMIC COMPONENTS FROM CORROSION

    SciTech Connect

    Prof. Stratis V. Sotirchos

    2001-02-01

    The main objective of this research project was the formulation of processes that can be used to prepare compositionally graded alumina/mullite coatings for protection from corrosion of silicon carbide components (monolithic or composite) used or proposed to be used in coal utilization systems (e.g., combustion chamber liners, heat exchanger tubes, particulate removal filters, and turbine components) and other energy-related applications. Since alumina has excellent resistance to corrosion but coefficient than silicon carbide, the key idea of this project has been to develop graded coatings with composition varying smoothly along their thickness between an inner (base) layer of mullite in contact with the silicon carbide component and an outer layer of pure alumina, which would function as the actual protective coating of the component. (Mullite presents very good adhesion towards silicon carbide and has thermal expansion coefficient very close to that of the latter.)

  11. In-situ formation of multiphase electron beam physical vapor deposited barrier coatings for turbine components

    DOEpatents

    Subramanian, Ramesh

    2001-01-01

    A turbine component (10), such as a turbine blade, is provided which is made of a metal alloy (22) and a base columnar thermal barrier coating (20) on the alloy surface, where a heat resistant ceramic oxide sheath material (32' or 34') covers the columns (28), and the sheath material is the reaction product of a precursor ceramic oxide sheath material and the base thermal barrier coating material.

  12. An investigation of enhanced capability thermal barrier coating systems for diesel engine components

    NASA Technical Reports Server (NTRS)

    Holtzman, R. L.; Layne, J. L.; Schechter, B.

    1984-01-01

    Material systems and processes for the development of effective and durable thermal barriers for heavy duty diesel engines were investigated. Seven coating systems were evaluated for thermal conductivity, erosion resistance, corrosion/oxidation resistance, and thermal shock resistance. An advanced coating system based on plasma sprayed particle yttria stabilized zirconia (PS/HYSZ) was judged superior in these tests. The measured thermal conductivity of the selected coating was 0.893 W/m C at 371 C. The PS/HYSZ coating system was applied to the piston crown, fire deck and valves of a single cylinder low heat rejection diesel engine. The coated engine components were tested for 24 hr at power levels from 0.83 MPa to 1.17 MPa brake mean effective pressure. The component coatings survived the engine tests with a minimum of distress. The measured fire deck temperatures decreased 86 C (155 F) on the intake side and 42 C (75 F) on the exhaust side with the coating applied.

  13. Advanced Multi-Component Defect Cluster Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    1990-01-01

    The advantages of using ceramic thermal barrier coatings in gas turbine engine hot sections include increased fuel efficiency and improved engine reliability. However, current thermal barrier coatings will not have the low thermal conductivity and necessary sintering resistance under higher operating temperatures and thermal gradients required by future advanced ultra-efficient and low-emission aircraft engines. In this paper, a novel oxide defect cluster design approach is described for achieving low thermal conductivity and excellent thermal stability of the thermal barrier coating systems. This approach utilizes multi-component rare earth and other metal cluster oxide dopants that are incorporated in the zirconia-yttria based systems, thus significantly reducing coating thermal conductivity and sintering resistance by effectively promoting the formation of thermodynamically stable, essentially immobile defect clusters and/or nanoscale phases. The performance of selected plasma-sprayed cluster oxide thermal barrier coating systems has been evaluated. The advanced multi-component thermal barrier coating systems were found to have significantly lower initial and long-term thermal conductivities, and better high temperature stability. The effect of oxide cluster dopants on coating thermal conductivity, sintering resistance, oxide grain growth behavior and durability will be discussed.

  14. Advanced Multi-Component Defect Cluster Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    2003-01-01

    The advantages of using ceramic thermal barrier coatings in gas turbine engine hot sections include increased fuel efficiency and improved engine reliability. However, current thermal barrier coatings will not have the low thermal conductivity and necessary sintering resistance under higher operating temperatures and thermal gradients required by future advanced ultra efficient and low emission aircraft engines. In this paper, a novel oxide defect cluster design approach is described for achieving low thermal conductivity and excellent thermal stability of the thermal barrier coating systems. This approach utilizes multi-component rare earth and other metal cluster oxide dopants that are incorporated in the zirconia-yttna based systems, thus significantly reducing coating thermal conductivity and sintering resistance by effectively promoting the formation of thermodynamically stable, essentially immobile defect clusters and/or nanoscale phases. The performance of selected plasma-sprayed cluster oxide thermal barrier coating systems has been evaluated. The advanced multi-component thermal barrier coating systems were found to have significantly lower initial and long-term thermal conductivities, and better high temperature stability. The effect of oxide cluster dopants on coating thermal conductivity, sintering resistance, oxide grain growth behavior and durability will be discussed.

  15. Microstructural and tensile characterization of Inconel 718 laser coatings for aeronautic components

    NASA Astrophysics Data System (ADS)

    Lambarri, Jon; Leunda, Josu; García Navas, Virginia; Soriano, Carlos; Sanz, Carmen

    2013-07-01

    The suitability of the laser cladding technique for manufacturing and repairing aeronautic components of Inconel 718 was evaluated. Multilayer coatings were deposited on Inconel 718 plates, using a continuous wave Nd:YAG laser. The microstructure of the laser cladding samples was investigated using optical and scanning electron microscopy and microhardness profiles were measured after different heat treatment stages. Finally, tensile tests were carried out on fully aged samples extracted from a massive multilayer coating. It was proven that the resulting coatings satisfy the industrial requirements for aeronautic applications, with mechanical properties well above the minimum specified values and with no detrimental phases or precipitates left after the heat treatment.

  16. Investigation of Er 2O 3 coating on liquid blanket components synthesized by the MOCVD process

    NASA Astrophysics Data System (ADS)

    Hishinuma, Y.; Tanaka, T.; Tanaka, T.; Nagasaka, T.; Yoshizawa, S.; Tasaki, Y.; Muroga, T.

    2011-10-01

    An electrical insulating coating on the blanket components such as ducts and walls is an attractive concept for reducting the Magneto Hydrodynamics pressure drop. Erbium oxide was shown to be a promising candidate coating because of its high stability in liquid lithium and high electrical resistivity. We have applied the Metal Organic Chemical Vapor Deposition (MOCVD) process to produce Er 2O 3 coating layers on the large areas and/or complicated shape components. Recently, we confirmed that Er 2O 3 coating layers were synthesized on a vanadium alloy and on silicon single crystal plates. In this work, we tried to form Er 2O 3 thin coating layer on the interior surface of the short quartz tube to demonstrate Er 2O 3 coating of components relevant to liquid blankets. The improvement found by the using an organic complex as the erbium source material and the effects of the deposition temperature for the further upgrading the MOCVD process were also evaluated.

  17. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Jordi Perez-Mariano; Angel Sanjurjo

    2006-06-30

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this period, we analyzed several coated and exposed samples of 409 steel by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). We report here on findings of this analysis: (1) A SS409 coupon that was coated with multilayered combined nitrides of Ti, Al, and Si showed adherent coatings on the surface; (2) A similarly coated coupon, after exposure to simulated coal gas at 900 C for 300 h, revealed that the coating has cracked during the exposure; (3) An SS409 coupon that was coated with nitrides of Ti and Si with a barrier layer of tungsten in between to improve the adhesion of the coating and to prevent outward diffusion of iron to the surface. (4) A porous coupon was coated with nitrides of Ti and Al and examination of the coupon revealed deposition of Ti at the interior surfaces. A similarly prepared coupon was exposed to simulated coal gas at 370 C for 300 h, and it showed no corrosion.

  18. On the Effects of the Rejuvenation Treatment on Mechanical and Microstructural Properties of IN-738 Superalloy

    NASA Astrophysics Data System (ADS)

    Monti, Cosimo; Giorgetti, Alessandro; Tognarelli, Leonardo; Mastromatteo, Francesco

    2017-05-01

    The main scope of this paper is to show the effects of a specific rejuvenation treatment studied for IN-38 on both the microstructure and the mechanical properties of the creep-damaged superalloy and to compare the tests results with the virgin material and with the recovery obtained through the standard heat treatment. This work will show that this rejuvenation treatment is able to recover the microstructure of creep-damaged specimens and that the creep and tensile properties of the rejuvenated alloy are even better than the virgin material for the tests performed. Moreover, it will be shown that the standard heat treatment provided for IN-738 is not able to fully recover the microstructure and that the creep properties of the superalloy during the tests have been lower than the virgin material.

  19. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2005-09-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this reporting period, we conducted several exposure tests with coated and uncoated coupons including a ''500-h'' test. The first experiment was a 316-h test and was designed to look at the performance of Ti/Ta nitride coatings, which seemed to fare the best in earlier tests. The next experiment was a 112-h test with a range of pure metals and commercially available materials. Its purpose was to help identify those metals that best withstood gasifier environment, and hence should be good ingredients for coatings. Finally, we ran a ''500-h'' test, which was also our milestone, with coupons coated with Ti/Ta nitride or Cr/Al coatings.

  20. Performance of heat-resistant silicon based coatings on plain carbon steel components in corrosive environments

    SciTech Connect

    Porcayo-Calderon, J.; Gonzalez-Rodriquez, J.G.; Martinez, L.

    1995-12-31

    A silicon based thermal spray coating was applied on the surface of a plain carbon steel baffle plate. The baffle was installed in the high temperature corrosion zone of a 350 MW boiler. At the same time, a 304 stainless steel baffle was installed nearby in order to compare the performance of the coating. During 13 month the boiler burnt heavy fuel oil with high contents of vanadium. After that, it was possible to inspect the structural state of the components, and it was found that the stainless steel baffle plates were destroyed, by corrosion almost completely (90% approximately). The carbon steel coated baffle plate practically did not suffer attack. The samples were studied employing scanning electron microscopy, X-ray microanalysis and X-ray diffraction, and the results shown that the coating was not attacked by vanadium salts of the molten slag. In addition nickel from the coating to the base metal, and iron from the base metal to the coating. The performance of the silicon based thermal spray coating was outstanding.

  1. Determination of the Ductile to Brittle Transition Temperature of Platinum-Aluminide Gas Turbine Blade Coatings

    DTIC Science & Technology

    1985-09-01

    to brittle transition temperature (DBTT) of five basic platinum- aluminide gas turbine blade coatings on a nickel-base superalloy (IN738). The results...gas turbine blade coatings on a nickel-base superalloy (IN738). The results of these tests were compared to similarly formed nickel- aluminide coatings ... aluminide coating became more widely used, it -°j.established itself as an excellent life extender for most superalloy blade materials. However, as

  2. 78 FR 52429 - Indirect Food Additives: Adhesives and Components of Coatings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration 21 CFR Part 175 Indirect Food Additives: Adhesives and Components of Coatings CFR Correction In Title 21 of the Code of Federal Regulations, Parts 170 to 199...

  3. LABORATORY EVALUATION OF NONSTICK COATINGS TO REDUCE INK ADHESION TO PRINTING PRESS COMPONENTS

    EPA Science Inventory

    The report gives results of a project to identify surface coatings or preparations that might reduce and/or eliminate the need for solvent cleaning of ink-feed-system components of printing equipment. The study was designed to provide qualitative, but not quantitative, results. T...

  4. Effects of model coal tar components on adhesion strength of polyurethane coating on steel plate

    SciTech Connect

    Yokoyama, N.; Fujino, K.

    2005-04-15

    In order to study the effects of coal tar components on the adhesion strength of a heavy duty anticorrosive coating formed with tar-urethane resin oil on a steel plate, polyurethane coatings that were compounded with 15 kinds of polycyclic aromatic compounds as model coal tar components were prepared. In the model coal tar, components, naphthalene, quinoline, 2-naphthol, and phenanthrene showed good compatibility with polyurethane. To test their heavy duty anticorrosive properties, tensile adhesion strength of the cured coatings prepared with the compatible model coal tar components was measured, and the change in tensile adhesion strength as a function of time during salt-water spray treatment was measured. We found that the systems compounded with naphthalene, 2-naphthol, and phenanthrene showed good properties in an ordinary state for adhesion strength. However, only the system with 2-naphthol was found to have good properties in the change of tensile adhesion strength as a function or time during salt-water spray treatment. The curing time of the system with 2-naphthol was slower than that or the others, i.e., we found an inverse proportion between curing speed and adhesion durability. We also measured the dynamic viscoelasticity of cured coatings.

  5. LABORATORY EVALUATION OF NONSTICK COATINGS TO REDUCE INK ADHESION TO PRINTING PRESS COMPONENTS

    EPA Science Inventory

    The report gives results of a project to identify surface coatings or preparations that might reduce and/or eliminate the need for solvent cleaning of ink-feed-system components of printing equipment. The study was designed to provide qualitative, but not quantitative, results. T...

  6. Damage to coated ZnSe optical components by high-power CO2 laser radiation

    NASA Astrophysics Data System (ADS)

    Haas, C. R.; Kreutz, Ernst-Wolfgang; Wesner, David A.

    1994-07-01

    Coated ZnSe optical components are irradiated with high-power, pulsed CO2 laser radiation ((lambda equals 10.6 micrometers , pulse length approximately 100 ns) at fluences up to 210 J/cm2. The components are characterized at various stages of irradiation by thermography, optical microscopy, stylus profilometry, and surface chemical analysis (x-ray photoemission and Auger electron spectroscopy). During irradiation no temperature in the component surface is observed. Two types of coating damage occur within the irradiated area of the component: a breaking apart of the ZnSe overlayer of the coating system over relatively large areas, and the formation of isolate craters of diameter approximately 30 - 50 micrometers extending in depth approximately 3 micrometers through the coating system down to the ZnSe substrate. Chemically, the irradiated area is characterized by an oxidation of both Zn and Se and an increase in the stoichiometric ratio of Zn to Se. These effects are especially pronounced at the crater defects, and are attributed to localized optical absorption, leading to thermal stress and chemical reactions of Zn and Se with atmospheric or adsorbed water and/or oxygen.

  7. Development of HVOF Sprayed Erosion/Oxidation Resistant Coatings for Composite Structural Components in Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Knight, R.; Ivosevic, M.; Twardowski, T. E.; Kalidindi, S. R.; Sutter, James K.; Kim, D. Y.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    Thermally sprayed coatings are being studied and developed as methods of enabling lightweight composites to be used more extensively as structural components in propulsion applications in order to reduce costs and improve efficiency through weight reductions. The primary goal of this work is the development of functionally graded material [FGM] polymer/metal matrix composite coatings to provide improved erosion/oxidation resistance to polyimide-based polymer matrix composite [PMC] substrates. The goal is to grade the coating composition from pure polyimide, similar to the PMC substrate matrix on one side, to 100 % WC-Co on the other. Both step-wise and continuous gradation of the loading of the WC-Co reinforcing phase are being investigated. Details of the coating parameter development will be presented, specifically the high velocity oxy-fuel [HVOF] combustion spraying of pure PMR-11 matrix material and layers of various composition PMR-II/WC-Co blends onto steel and PMR-15 composite substrates. Results of the HVOF process optimization, microstructural characterization, and analysis will be presented. The sprayed coatings were evaluated using standard metallographic techniques - optical and scanning electron microscopy [SEM]. An SEM + electron dispersive spectroscopy [EDS] technique has also been used to confirm retention of the PMR-II component. Results of peel/butt adhesion testing to determine adhesion will also be presented.

  8. Development of HVOF Sprayed Erosion/Oxidation Resistant Coatings for Composite Structural Components in Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Ivosevic, M.; Twardowski, T.; Kalidindi, S.; Knight, R.; Sutter, J.; Kim, D. Y.

    1990-01-01

    Thermally sprayed coatings are being studied and developed as methods of enabling lightweight composites to be used more extensively as structural components in propulsion applications in order to reduce costs and improve efficiency through weight reductions. The primary goal of this work is the development of functionally graded material [FGM] polymer/metal matrix composite coatings to provide improved erosion/oxidation resistance to polyimide-based polymer matrix composite [PMC] substrates. The goal is to grade the coating composition from pure polyimide, similar to the PMC substrate matrix on one side, to 100% WC-Co on the other. Both step-wise and continuous gradation of the loading of the WC-Co reinforcing phase are being investigated, Details of the coating parameter development will be presented, specifically the high velocity oxy-fuel [HVOF] combustion spraying of pure PMR-I1 matrix material and layers of various composition PMR-II/WC-Co blends onto steel and PMR-15 composite substrates. Results of the HVOF process optimization, microstructural characterization, and analysis will be presented. The sprayed coatings were evaluated using standard metallographic techniques - optical and scanning electron microscopy [SEMI. An SEM + electron dispersive spectroscopy [EDS] technique has also been used to confirm retention of the PMR-I1 component. Results of peel/butt adhesion testing to determine adhesion will also be presented.

  9. Surface engineering glass-metal coatings designed for induction heating of ceramic components

    NASA Astrophysics Data System (ADS)

    Khan, Amir Azam; Labbe, Jean Claude

    2014-06-01

    The term Surface Engineering is of relatively recent origin and use, however, the use of coatings and treatments to render surfaces of materials more suitable for certain application or environment is not new. With the advent of Vacuum Technology, Surface Engineering has gained a whole new impetus, whereby expensive materials with adequate mechanical, chemical and thermal properties are being coated or treated on their surfaces in order to achieve what is called as Surface Engineered materials. The present paper presents an overview of recent achievements in Surface Engineering and gives a detailed view of a specific application where glass-metal composite coatings were deposited on ceramic components in order to render them sensitive to induction heating. Sintered glaze coatings containing silver particles in appropriate concentration can be used for the induction heating of porcelain. Mixtures of glass ceramic powders with silver are used to prepare self-transfer patterns, which are deposited over porcelain. Several configurations of these coatings, which are aesthetic to start with, are employed and heating patterns are recorded. The microstructure of these coatings is discussed in relation to the heating ability by a classical household induction system. The results show that this technique is practical and commercially viable.

  10. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2006-01-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this period we tested coated alloy coupons under conditions designed to mimic the conditions in the filter unit after the high-temperature heat recovery unit (HTHRU). The filter unit is another important area where corrosion has caused unscheduled downtime, and the remedy has been the use of sintered metal tubes made of expensive alloys such as inconel. The objective of our test was to determine if those coatings on 400-series steel that were not able to withstand the harsher conditions of the HTHRU, may be sufficiently resistant for use in the filter unit, at the reduced temperatures. Indeed, most of our coatings survived well; the exceptions were the coated porous samples of SS316. We continued making improvements to our coatings apparatus and the procedure began during the last quarter. As a result of these modifications, the coupons we are now producing are uniform. We describe the improved procedure for preparing diffusion coatings. Finally, because porous samples of steel in grades other than SS316 are not readily available, we also decided to procure SS409 powder and fabricate our own sintered porous coupons.

  11. Cavitation Erosion in Hydraulic Turbine Components and Mitigation by Coatings: Current Status and Future Needs

    NASA Astrophysics Data System (ADS)

    Singh, Raghuvir; Tiwari, S. K.; Mishra, Suman K.

    2012-07-01

    Cavitation erosion is a frequently observed phenomenon in underwater engineering materials and is the primary reason for component failure. The damage due to cavitation erosion is not yet fully understood, as it is influenced by several parameters, such as hydrodynamics, component design, environment, and material chemistry. This article gives an overview of the current state of understanding of cavitation erosion of materials used in hydroturbines, coatings and coating methodologies for combating cavitation erosion, and methods to characterize cavitation erosion. No single material property fully characterizes the resistance to cavitation erosion. The combination of ultimate resilience, hardness, and toughness rather may be useful to estimate the cavitation erosion resistance of material. Improved hydrodynamic design and appropriate surface engineering practices reduce damage due to cavitation erosion. The coatings suggested for combating the cavitation erosion encompasses carbides (WC Cr2C3, Cr3C2, 20CrC-80WC), cermets of different compositions (e.g., 56W2C/Ni/Cr, 41WC/Ni/Cr/Co), intermetallic composites, intermetallic matrix composites with TiC reinforcement, composite nitrides such as TiAlN and elastomers. A few of them have also been used commercially. Thermal spraying, arc plasma spraying, and high velocity oxy-fuel (HVOF) processes have been used commercially to apply the coatings. Boronizing, laser surface hardening and cladding, chemical vapor deposition, physical vapor deposition, and plasma nitriding have been tried for surface treatments at laboratory levels and have shown promise to be used on actual components.

  12. Chemical reactions involved in the initiation of hot corrosion of IN-738

    NASA Technical Reports Server (NTRS)

    Fryburg, G. C.; Kohl, F. J.; Stearns, C. A.

    1984-01-01

    Sodium-sulfate-induced hot corrosion of preoxidized IN-738 was studied at 975 C with special emphasis placed on the processes occurring during the long induction period. Thermogravimetric tests were run for predetermined periods of time, and then one set of specimens was washed with water. Chemical analysis of the wash solutions yielded information about water soluble metal salts and residual sulfate. A second set of samples was cross sectioned dry and polished in a nonaqueous medium. Element distributions within the oxide scale were obtained from electron microprobe X-ray micrographs. Evolution of SO was monitored throughout the thermogravimetric tests. Kinetic rate studies were performed for several pertinent processes; appropriate rate constants were obtained from the following chemical reactions; Cr203 + 2 Na2S04(1) + 3/2 02 yields 2 Na2Cr04(1) + 2 S03(g)n TiO2 + Na2S04(1) yields Na20(T102)n + 503(g)n T102 + Na2Cro4(1) yields Na2(T102)n + Cr03(g).

  13. Kinetics and Microstructural Investigation of High-Temperature Oxidation of IN-738LC Super Alloy

    NASA Astrophysics Data System (ADS)

    Hamidi, S.; Rahimipour, M. R.; Eshraghi, M. J.; Hadavi, S. M. M.; Esfahani, H.

    2017-02-01

    The present study was carried out to investigate the kinetics and the surface chemistry of the oxide layers formed on the IN-738LC super alloy during high-temperature oxidation at 950 °C in air from 1 to 260 h. Oxidation kinetics were studied by mass gain measurement. The oxide layers were characterized by field emission scanning electron microscope, elemental distribution map, energy-dispersive spectroscopy as well as x-ray diffractometry (XRD). The oxidation kinetics followed the parabolic law. The XRD analysis revealed that the oxide scale contained mainly NiO, Ni (Cr, Al)2O4, Al2O3, TiO2 and Cr2O3. The oxide structure, from the top surface down to the substrate, was clarified by elemental map distribution studies as Ni-Ti oxides, Cr-Ti oxides, Cr2O3 oxide band, Ni-Co-Cr-W oxide and finally a blocky Al2O3 region. The oxidation scales were composed of three distinct layers of the outer and mid layers enriched by TiO2 and Cr2O3, NiCr2O4 oxide, respectively, and the innermost layer was composed of Al2O3 and matrix alloy. The depleted gamma prime layer was formed under the oxidation scales due to the impoverishment of Al and Ti which were induced by the formation of Al2O3 and TiO2.

  14. Kinetics and Microstructural Investigation of High-Temperature Oxidation of IN-738LC Super Alloy

    NASA Astrophysics Data System (ADS)

    Hamidi, S.; Rahimipour, M. R.; Eshraghi, M. J.; Hadavi, S. M. M.; Esfahani, H.

    2016-12-01

    The present study was carried out to investigate the kinetics and the surface chemistry of the oxide layers formed on the IN-738LC super alloy during high-temperature oxidation at 950 °C in air from 1 to 260 h. Oxidation kinetics were studied by mass gain measurement. The oxide layers were characterized by field emission scanning electron microscope, elemental distribution map, energy-dispersive spectroscopy as well as x-ray diffractometry (XRD). The oxidation kinetics followed the parabolic law. The XRD analysis revealed that the oxide scale contained mainly NiO, Ni (Cr, Al)2O4, Al2O3, TiO2 and Cr2O3. The oxide structure, from the top surface down to the substrate, was clarified by elemental map distribution studies as Ni-Ti oxides, Cr-Ti oxides, Cr2O3 oxide band, Ni-Co-Cr-W oxide and finally a blocky Al2O3 region. The oxidation scales were composed of three distinct layers of the outer and mid layers enriched by TiO2 and Cr2O3, NiCr2O4 oxide, respectively, and the innermost layer was composed of Al2O3 and matrix alloy. The depleted gamma prime layer was formed under the oxidation scales due to the impoverishment of Al and Ti which were induced by the formation of Al2O3 and TiO2.

  15. Chemical mechanisms and reaction rates for the initiation of hot corrosion of IN-738

    NASA Technical Reports Server (NTRS)

    Fryburg, G. C.; Kohl, F. J.; Stearns, C. A.

    1984-01-01

    Sodium-sulfate-induced hot corrosion of preoxidized IN-738 was studied at 975 C with special emphasis placed on the processes occurring during the long induction period. Thermogravimetric tests were run for predetermined periods of time, and then one set of specimens was washed with water. Chemical analysis of the wash solutions yielded information about water soluble metal salts and residual sulfate. A second set of samples was cross sectioned dry and polished in a nonaqueous medium. Element distributions within the oxide scale were obtained from electron microprobe X-ray micrographs. Evolution of SO was monitored throughout the thermogravimetric tests. Kinetic rate studies were performed for several pertinent processes; appropriate rate constants were obtained from the following chemical reactions: Cr2O3 + 2 Na2SO4(1) + 3/2 O2 yields 2 Na2CrO4(1) + 2 SO3(g)n TiO2 + Na2SO4(1) yields Na2O(TiO2)n + SO3(g)n TiO2 + Na2CrO4(1) yields Na2O(TiO2)n + CrO3(g).

  16. Tribological characterization of zirconia coatings deposited on Ti6Al4V components for orthopedic applications.

    PubMed

    Berni, M; Lopomo, N; Marchiori, G; Gambardella, A; Boi, M; Bianchi, M; Visani, A; Pavan, P; Russo, A; Marcacci, M

    2016-05-01

    One of the most important issues leading to the failure of total joint arthroplasty is related to the wear of the plastic components, which are generally made of ultra high molecular weight polyethylene (UHMWPE). Therefore, the reduction of joint wear represents one of the main challenges the research in orthopedics is called to address nowadays. Surface treatments and coatings have been recognized as innovative methods to improve tribological properties, also in the orthopedic field. This work investigated the possibility to realize hard ceramic coatings on the metal component of a prosthesis, by means of Pulsed Plasma Deposition, in order to reduce friction and wear in the standard coupling against UHMWPE. Ti6Al4V substrates were coated with a 2 μm thick yttria-stabilized zirconia (YSZ) layer. The mechanical properties of the YSZ coatings were assessed by nanoindentation tests performed on flat Ti6Al4V substrates. Tribological performance was evaluated using a ball-on-disk tribometer in dry and lubricated (i.e. with fetal bovine serum) highly-stressing conditions, up to an overall distance of 10 km. Tribology was characterized in terms of coefficient of friction (CoF) and wear rate of the UHMWPE disk. After testing, specimens were analyzed through optical microscopy and SEM images, in order to check the wear degradation mechanisms. Progressive loading scratch tests were also performed in dry and wet conditions to determine the effects of the environment on the adhesion of the coating. Our results supported the beneficial effect of YSZ coating on metal components. In particular, the proposed solution significantly reduced UHMWPE wear rate and friction. At 10 km of sliding distance, a wear rate reduction of about 18% in dry configuration and of 4% in presence of serum, was obtained by the coated group compared to the uncoated group. As far as friction in dry condition is concerned, the coating allowed to maintain low CoF values until the end of the tests, with an

  17. Occupational dermatoses from one-component epoxy coatings containing a modified polyamine hardener.

    PubMed

    Yokota, K; Johyama, Y; Yamaguchi, K

    2000-07-01

    In an electronics plant, 2 one-component epoxy coatings containing a modified polyamine hardener were used as covering materials for protecting important information on police radio circuit boards. The resinous parts of the coatings consisted of epoxy resins based on diglycidyl ether of bisphenol F. The hardener was a dimethylaminopropylamine (DMAPA)-epoxy adduct and contained about 0.16% free DMAPA. Of 105 workers, 17 (16%) were diagnosed to have work-related dermatitis but were not patch tested. The hands were the commonly affected region (13 out of 17 cases). The latent period of dermatitis was very short (mean 21.5 days). The work-related dermatoses were closely related to the type of work and working periods. In the present study, hand protection and the introduction of automation have been demonstrated to be useful for the prevention of epoxy coating dermatitis.

  18. Accelerated life assessment of coating on the radar structure components in coastal environment.

    PubMed

    Liu, Zhe; Ming, ZhiMao

    2016-07-04

    This paper aimed to build an accelerated life test scheme and carry out quantitative analysis between accelerated life test in the laboratory and actual service for the coating composed of epoxy primer and polyurethane paint on structure components of some kind of radar served in the coastal environment of South China Sea. The accelerated life test scheme was built based on the service environment and failure analysis of the coating. The quantitative analysis between accelerated life test and actual service was conducted by comparing the gloss loss, discoloration, chalking, blistering, cracking and electrochemical impedance spectroscopy of the coating. The main factors leading to the coating failure were ultraviolet radiation, temperature, moisture, salt fog and loads, the accelerated life test included ultraviolet radiation, damp heat, thermal shock, fatigue and salt spray. The quantitative relationship was that one cycle of the accelerated life test was equal to actual service for one year. It was established that one cycle of the accelerated life test was equal to actual service for one year. It provided a precise way to predict actual service life of newly developed coatings for the manufacturer.

  19. Biomimetic component coating on 3D scaffolds using high bioactivity of mesoporous bioactive ceramics.

    PubMed

    Yun, Hui-suk; Kim, Sang-Hyun; Khang, Dongwoo; Choi, Jungil; Kim, Hui-hoon; Kang, Minji

    2011-01-01

    Mesoporous bioactive glasses (MBGs) are very attractive materials for use in bone tissue regeneration because of their extraordinarily high bone-forming bioactivity in vitro. That is, MBGs may induce the rapid formation of hydroxy apatite (HA) in simulated body fluid (SBF), which is a major inorganic component of bone extracellular matrix (ECM) and comes with both good osteoconductivity and high affinity to adsorb proteins. Meanwhile, the high bioactivity of MBGs may lead to an abrupt initial local pH variation during the initial Ca ion-leaching from MBGs at the initial transplant stage, which may induce unexpected negative effects on using them in in vivo application. In this study we suggest a new way of using MBGs in bone tissue regeneration that can improve the strength and make up for the weakness of MBGs. We applied the outstanding bone-forming bioactivity of MBG to coat the main ECM components HA and collagen on the MBG-polycarplolactone (PCL) composite scaffolds for improving their function as bone scaffolds in tissue regeneration. This precoating process can also expect to reduce initial local pH variation of MBGs. The MBG-PCL scaffolds were immersed in the mixed solution of the collagen and SBF at 37°C for 24 hours. The coating of ECM components on the MBG-PCL scaffolds and the effect of ECM coating on in vitro cell behaviors were confirmed. The ECM components were fully coated on MBG-PCL scaffolds after immersing in SBF containing dilute collagen-I solution only for 24 hours due to the high bone-forming bioactivity of MBG. Both cell affinity and osteoconductivity of MBG-PCL scaffolds were dramatically enhanced by this precoating process. The precoating process of ECM components on MBG-PCL scaffold using a high bioactivity of MBG was not only effective in enhancing the functionality of scaffolds but also effective in eliminating the unexpected side effect. The MBG-PCL scaffold-coated ECM components ideally satisfied the required conditions of scaffold in

  20. Morphological characterisation of complex powder used for protective coatings for geothermal plant components

    NASA Astrophysics Data System (ADS)

    Csaki, I.; Karlsdottir, S. N.; Buzaianu, A.; Serghiuta, S.; Popescu, G.; Motoiu, V. A.; Ragnarstottir, K. R.; Guðlaugsson, S.

    2016-06-01

    This paper aims to review the morphological characteristics, microstructures, physical and chemical properties of two complex composite powders: Ni18Cr5Si2B and Ni21Cr11Al2.5Y. These powders will be used as an option for coating geothermal turbine blades to prevent corrosion. The corrosion process in the steam turbine results in damages being recognized as the leading cause of reduced availability in geothermal power plants and is depends on temperature, mechanical and vaporous carryover of impurities and water treatment. Thermal spraying is a suitable technique for coating layers with wear and corrosion resistance. Therefore this technique could be successfully used in geothermal applications for obtaining coatings layers from new complex composite powders protecting the turbine blades from corrosions and good control of steam chemistry. The composite powders were investigated using X-ray diffraction and electronic microscopy to provide detailed information about composites morphological modifications. The results obtained after morphological evaluation are encouraging for using these composite powders as an option for coating geothermal components using thermal spraying technique.

  1. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Jordi Perez; Marc Hornbostel; Kai-Hung Lau; Angel Sanjurjo

    2007-05-31

    Advanced electric power generation systems use a coal gasifier to convert coal to a gas rich in fuels such as H{sub 2} and CO. The gas stream contains impurities such as H{sub 2}S and HCl, which attack metal components of the coal gas train, causing plant downtime and increasing the cost of power generation. Corrosion-resistant coatings would improve plant availability and decrease maintenance costs, thus allowing the environmentally superior integrated-gasification-combined-cycle (IGCC) plants to be more competitive with standard power-generation technologies. Heat-exchangers, particle filters, turbines, and other components in the IGCC system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy will improve is resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. The Fe- and Ni-based high-temperature alloys are susceptible to sulfidation attack unless they are fortified with high levels of Cr, Al, and Si. To impart corrosion resistance, these elements need not be in the bulk of the alloy and need only be present at the surface layers. In this study, the use of corrosion-resistant coatings on low alloy steels was investigated for use as high-temperature components in IGCC systems. The coatings were deposited using SRI's fluidized-bed reactor chemical vapor deposition technique. Diffusion coatings of Cr and Al were deposited by this method on to dense and porous, low alloy stainless steel substrates. Bench-scale exposure tests at 900 C with a simulated coal gas stream containing 1.7% H{sub 2}S showed that the low alloy steels such SS405 and SS409 coated with {approx

  2. Emittance and absorptance of the National Aeronautics and Space Administration ceramic thermal barrier coating. [for gas turbine engine components

    NASA Technical Reports Server (NTRS)

    Liebert, C. H.

    1978-01-01

    The spectral emittance of a NASA developed zirconia ceramic thermal barrier coating system, consisting of a metal substrate, a layer of Ni-Cr-Al-Y bond material and a layer of yttria-stabilized zirconia ceramic material, is analyzed. The emittance, needed for evaluation of radiant heat loads on cooled coated gas turbine components, was measured over a range of temperatures that would be typical of its use on such components. Emittance data were obtained with a spectrometer, a reflectometer and a radiation pyrometer at a single bond coating thickness of 0.010 cm and at a ceramic coating thickness of 0-0.076 cm. The data were transformed into the hemispherical total emittance and were correlated to the ceramic coating thickness and temperature using multiple-regression curve-fitting techniques. The system was found to be highly reflective, and, consequently, capable of significantly reducing radiation heat loads on cooled gas turbine engine components.

  3. Structural and mechanical characterization of detonation coatings formed by reaction products of titanium with components of the spraying atmosphere

    NASA Astrophysics Data System (ADS)

    Ulianitsky, Vladimir Yu.; Dudina, Dina V.; Panin, Sergey V.; Vlasov, Ilya V.; Batraev, Igor S.; Bokhonov, Boris B.

    2016-11-01

    Structural characterization of detonation deposits formed by reaction products of titanium with the components of the spraying atmosphere showed that ceramic-based coatings of unique microstructures—consisting of alternating layers of different compositions—can be formed. For the first time, mechanical characteristics of the coatings formed by reaction-accompanied detonation spraying of titanium were evaluated. It was found that high-yield transformation of titanium into oxides and nitrides during spraying can result in the formation of coatings with high fracture resistance and interface fracture toughness. The hardness of the coatings measured along the cross-section of the specimens was higher than that on the surface of the coatings, which indicated mechanical anisotropy of the deposited material. In terms of mechanical properties, coatings formed by the reaction products appear to be more attractive than those specially treated to preserve metallic titanium.

  4. A Robot Trajectory Optimization Approach for Thermal Barrier Coatings Used for Free-Form Components

    NASA Astrophysics Data System (ADS)

    Cai, Zhenhua; Qi, Beichun; Tao, Chongyuan; Luo, Jie; Chen, Yuepeng; Xie, Changjun

    2017-08-01

    This paper is concerned with a robot trajectory optimization approach for thermal barrier coatings. As the requirements of high reproducibility of complex workpieces increase, an optimal thermal spraying trajectory should not only guarantee an accurate control of spray parameters defined by users (e.g., scanning speed, spray distance, scanning step, etc.) to achieve coating thickness homogeneity but also help to homogenize the heat transfer distribution on the coating surface. A mesh-based trajectory generation approach is introduced in this work to generate path curves on a free-form component. Then, two types of meander trajectories are generated by performing a different connection method. Additionally, this paper presents a research approach for introducing the heat transfer analysis into the trajectory planning process. Combining heat transfer analysis with trajectory planning overcomes the defects of traditional trajectory planning methods (e.g., local over-heating), which helps form the uniform temperature field by optimizing the time sequence of path curves. The influence of two different robot trajectories on the process of heat transfer is estimated by coupled FEM models which demonstrates the effectiveness of the presented optimization approach.

  5. A Robot Trajectory Optimization Approach for Thermal Barrier Coatings Used for Free-Form Components

    NASA Astrophysics Data System (ADS)

    Cai, Zhenhua; Qi, Beichun; Tao, Chongyuan; Luo, Jie; Chen, Yuepeng; Xie, Changjun

    2017-10-01

    This paper is concerned with a robot trajectory optimization approach for thermal barrier coatings. As the requirements of high reproducibility of complex workpieces increase, an optimal thermal spraying trajectory should not only guarantee an accurate control of spray parameters defined by users (e.g., scanning speed, spray distance, scanning step, etc.) to achieve coating thickness homogeneity but also help to homogenize the heat transfer distribution on the coating surface. A mesh-based trajectory generation approach is introduced in this work to generate path curves on a free-form component. Then, two types of meander trajectories are generated by performing a different connection method. Additionally, this paper presents a research approach for introducing the heat transfer analysis into the trajectory planning process. Combining heat transfer analysis with trajectory planning overcomes the defects of traditional trajectory planning methods (e.g., local over-heating), which helps form the uniform temperature field by optimizing the time sequence of path curves. The influence of two different robot trajectories on the process of heat transfer is estimated by coupled FEM models which demonstrates the effectiveness of the presented optimization approach.

  6. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Jordi Perez Mariano; Angel Sanjurjo

    2006-09-30

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. The primary activity this period was preparation and presentation of the findings on this project at the Twenty-Third annual Pittsburgh Coal Conference. Dr. Malhotra attended this conference and presented a paper. A copy of his presentation constitutes this quarterly report.

  7. Development of wear resistant ceramic coatings for diesel engine components. Final report

    SciTech Connect

    Haselkorn, M.H.

    1992-04-01

    Improved fuel economy and a reduction of emissions can be achieved by insulation of the combustion chamber components to reduce heat rejection. However, insulating the combustion chamber components will also increase the operating temperature of the piston ring/cylinder liner interface from approximately 150{degree}C to over 300{degree}C. Existing ring/liner materials can not withstand these higher operating temperatures and for this reason, new materials need to be developed for this critical tribological interface. The overall goal of this program is the development of piston ring/cylinder liner material pairs which would be able to provide the required friction and wear properties at these more severe operating conditions. More specifically, this program first selected, and then evaluated, potential d/wear resistant coatings which could be applied to either piston rings an or cylinder liners and provide, at 350{degree}C under lubricated conditions, coefficients of friction below 0.1 and wear rates of less than 25 {times} lO{sup {minus}6} mm/hour. The processes selected for applying the candidate wear resistant coatings to piston rings and/or cylinder liners were plasma spraying, chemical vapor, physical vapor and low temperature arc vapor deposition techniques as well as enameling techniques.

  8. 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)

  9. 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)

  10. Partitioning behavior of aromatic components in jet fuel into diverse membrane-coated fibers.

    PubMed

    Baynes, Ronald E; Xia, Xin-Rui; Barlow, Beth M; Riviere, Jim E

    2007-11-01

    Jet fuel components are known to partition into skin and produce occupational irritant contact dermatitis (OICD) and potentially adverse systemic effects. The purpose of this study was to determine how jet fuel components partition (1) from solvent mixtures into diverse membrane-coated fibers (MCFs) and (2) from biological media into MCFs to predict tissue distribution. Three diverse MCFs, polydimethylsiloxane (PDMS, lipophilic), polyacrylate (PA, polarizable), and carbowax (CAR, polar), were selected to simulate the physicochemical properties of skin in vivo. Following an appropriate equilibrium time between the MCF and dosing solutions, the MCF was injected directly into a gas chromatograph/mass spectrometer (GC-MS) to quantify the amount that partitioned into the membrane. Three vehicles (water, 50% ethanol-water, and albumin-containing media solution) were studied for selected jet fuel components. The more hydrophobic the component, the greater was the partitioning into the membranes across all MCF types, especially from water. The presence of ethanol as a surrogate solvent resulted in significantly reduced partitioning into the MCFs with discernible differences across the three fibers based on their chemistries. The presence of a plasma substitute (media) also reduced partitioning into the MCF, with the CAR MCF system being better correlated to the predicted partitioning of aromatic components into skin. This study demonstrated that a single or multiple set of MCF fibers may be used as a surrogate for octanol/water systems and skin to assess partitioning behavior of nine aromatic components frequently formulated with jet fuels. These diverse inert fibers were able to assess solute partitioning from a blood substitute such as media into a membrane possessing physicochemical properties similar to human skin. This information may be incorporated into physiologically based pharmacokinetic (PBPK) models to provide a more accurate assessment of tissue dosimetry of

  11. Plasma Response to Lithium-Coated Plasma-Facing Components in the National Spherical Torus Experiment

    SciTech Connect

    M.G. Bell, H.W. Kugel, R. Kaita, L.E. Zakharov, H. Schneider, B.P. LeBlanc, D. Mansfield, R.E. Bell, R. Maingi, S. Ding, S.M. Kaye, S.F. Paul, S.P. Gerhardt, J.M. Canik, J.C. Hosea, G. Taylor and the NSTX Research Team

    2009-08-20

    Experiments in the National Spherical Torus Experiment (NSTX) have shown beneficial effects on the performance of divertor plasmas as a result of applying lithium coatings on the graphite and carbonfiber- composite plasma-facing components. These coatings have mostly been applied by a pair of lithium evaporators mounted at the top of the vacuum vessel which inject collimated streams of lithium vapor towards the lower divertor. In NBI-heated, deuterium H-mode plasmas run immediately after the application of lithium, performance modifications included decreases in the plasma density, particularly in the edge, and inductive flux consumption, and increases in the electron and ion temperatures and the energy confinement time. Reductions in the number and amplitude of ELMs were observed, including complete ELM suppression for periods up to 1.2 s, apparently as a result of altering the stability of the edge. However, in the plasmas where ELMs were suppressed, there was a significant secular increase in the effective ion charge Zeff and the radiated power as a result of increases in the carbon and medium-Z metallic impurities, although not of lithium itself which remained at a very low level in the plasma core, <0.1%. The impurity buildup could be inhibited by repetitively triggering ELMs with the application of brief pulses of an n = 3 radial field perturbation. The reduction in the edge density by lithium also inhibited parasitic losses through the scrape-off layer of ICRF power coupled to the plasma, enabling the waves to heat electrons in the core of H-mode plasmas produced by NBI. Lithium has also been introduced by injecting a stream of chemically stabilized, fine lithium powder directly into the scrape-off layer of NBI-heated plasmas. The lithium was ionized in the SOL and appeared to flow along the magnetic field to the divertor plates. This method of coating produced similar effects to the evaporated lithium but at lower amounts.

  12. Isothermal Oxidation Behavior of VC and Columnar Structured Thermal Barrier Coatings Deposited by Suspension Plasma Spray Technology

    NASA Astrophysics Data System (ADS)

    Li, Xiaolong; Yang, Qi; Huang, Xiao; Tang, Zhaolin

    2015-08-01

    The effects of different thermal barrier coating (TBC) top coat structures and substrate alloys on the isothermal oxidation behaviors of TBC systems were investigated at 1080 °C in lab air. The tested TBC systems consisted of two nickel-based superalloy substrates (CMSX-4 and IN738LC), a platinum aluminide bond coat and two 8YSZ top coats (vertical cracked and columnar structured). Samples with IN738LC substrate demonstrated longer isothermal oxidation lives than the counterparts with CMSX-4 substrate. Outward refractory elemental diffusion in coating systems with CMSX-4 substrate and void formation at the interface between thermally grown oxide and bond coat was found to be responsible for the early failure of TBCs. Columnar structured YSZ top coat seemed to provide better protection of the bond coating and substrate, marginally delaying the failure of the both coating systems with IN738LC and CMSX-4.

  13. Microstructural studies on failure mechanisms in thermo-mechanical fatigue of repaired DS R80 and IN 738 Superalloys

    NASA Astrophysics Data System (ADS)

    Abrokwah, Emmanuel Otchere

    Directionally solidified Rene 80 (DS R80) and polycrystalline Inconel 738(IN 738) Superalloys were tested in thermo-mechanical fatigue (TMF) over the temperature range of 500-900°C and plastic strain range from 0.1 to 0.8% using a DSI Gleeble thermal simulator. Thermo-mechanical testing was carried out on the parent material (baseline) in the conventional solution treated and aged condition (STA), as well as gas tungsten arc welded (GTAW) with an IN-738 filler, followed by solution treatment and ageing. Comparison of the baseline alloy microstructure with that of the welded and heat treated alloy showed that varying crack initiation mechanisms, notably oxidation by stress assisted grain boundary oxidation, grain boundary MC carbides fatigue crack initiation, fatigue crack initiation from sample surfaces, crack initiation from weld defects and creep deformation were operating, leading to different “weakest link” and failure initiation points. The observations from this study show that the repaired samples had extra crack initiation sites not present in the baseline, which accounted for their occasional poor fatigue life. These defects include lack of fusion between the weld and the base metal, fusion zone cracking, and heat affected zone microfissures.

  14. Optical coating performance for heat reflectors of JWST-ISIM electronic component

    NASA Astrophysics Data System (ADS)

    Quijada, Manuel A.; Bousquet, Robert; Garrison, Matt; Perrygo, Chuck; Threat, Felix; Rashford, Robert

    2008-07-01

    The James Webb Space Telescope (JWST) consists of an infrared-optimized Optical Telescope Element (OTE) that is cooled down to 40 degrees Kelvin. A second adjacent component to the OTE is the Integrated Science Instrument Module, or ISIM. This module includes the electronic compartment, which provides the mounting surfaces and ambient thermally controlled environment for the instrument control electronics. Dissipating the 200 watts generated from the ISIM structure away from the OTE is of paramount importance so that the spacecraft's own heat does not interfere with the infrared light detected from distant cosmic sources. This technical challenge is overcome by a thermal subsystem unit that provides passive cooling to the ISIM control electronics. The proposed design of this thermal radiator consists of a lightweight structure made out of composite materials and low-emittance metal coatings. In this paper, we will present characterizations of the coating emittance, bidirectional reflectance, and mechanical structure design that will affect the performance of this passive cooling reflector.

  15. Effects of dehumidification drying environment on drying speed of one component waterborne wood top coating

    NASA Astrophysics Data System (ADS)

    Lu, Zeguang; Tang, Tong; Zhou, Ge; Jia, Wanda; Wang, Meng; Xu, Jing; Bai, Shihong

    2016-03-01

    In this study, the effects of dehumidification drying environment including air temperature and relative humidity and velocity on drying speed of one component waterborne wood top coating are studied by Orthogonal experimental design and the results are analyzed creatively by Duncan analyses. It is found that during the dehumidification drying process, hard drying time is decreasing with the increasing air temperature and velocity and decreasing relative humidity. Air velocity is extremely significant to hard drying time, which is more significant than relative humidity, and relative humidity is more significant than air temperature. The difference of hard drying time is significant when the difference is 5 min and above, and it is extremely significant when the difference is 10 min and above, which are critical to judge the hard time in practice.

  16. FUNCTIONALLY GRADED ALUMINA/MULLITE COATINGS FOR PROTECTION OF SILICON CARBIDE CERAMIC COMPONENTS FROM CORROSION

    SciTech Connect

    1997-10-01

    The main objective of this research project is the formulation of processes that can be used to prepare compositionally graded alumina/mullite coatings for protection from corrosion of silicon carbide components (monolithic or composite) used or proposed to be used in coal utilization systems (e.g., combustion chamber liners, heat exchanger tubes, particulate removal filters, and turbine components) and other energy-related applications. Mullite will be employed as the inner (base) layer and the composition of the film will be continuously changed to a layer of pure alumina, which will function as the actual protective coating of the component. Chemical vapor deposition reactions of silica, alumina, and aluminosilicates (mullite) through hydrolysis of aluminum and silicon chlorides in the presence of CO{sub 2} and H{sub 2} will be employed to deposit compositionally graded films of mullite and alumina. Our studies will include the kinetic investigation of the silica, alumina, and aluminosilicate deposition processes, characterization of the composition, microstructure, surface morphology, and mechanical behavior of the prepared films, and modeling of the various deposition processes. During this six-month reporting period, we continued the work on the development and construction of the thermogravimetric chemical vapor deposition system that we intend to employ for studying the deposition of alumina, silica, and aluminosilicates (such as mullite) from mixtures of metal chlorides in H{sub 2} and CO{sub 2}. Specifically, we worked on the development of the tubular flow reactor that will be used for producing aluminum chloride for delivery to the chemical vapor deposition system and of the vapor and gas supply system. Various problems arising from condensation of aluminum chlorides in some sections of the supply line were resolved, and we expect to perform experiments using mixtures containing AlCl{sub 3} in the next reporting period. Preliminary experiments on the

  17. Manufacturing and coating of optical components for the EnMAP hyperspectral imager

    NASA Astrophysics Data System (ADS)

    Schürmann, M.; Gäbler, D.; Schlegel, R.; Schwinde, S.; Peschel, T.; Damm, C.; Jende, R.; Kinast, J.; Müller, S.; Beier, M.; Risse, S.; Sang, B.; Glier, M.; Bittner, H.; Erhard, M.

    2016-07-01

    The optical system of the hyperspectral imager of the Environmental Mapping and Analysis Program (EnMAP) consists of a three-mirror anastigmat (TMA) and two independent spectrometers working in the VNIR and SWIR spectral range, respectively. The VNIR spectrometer includes a spherical NiP coated Al6061 mirror that has been ultra-precisely diamond turned and finally coated with protected silver as well as four curved fused silica (FS) and flint glass (SF6) prisms, respectively, each with broadband antireflection (AR) coating, while the backs of the two outer prisms are coated with a high-reflective coating. For AR coating, plasma ion assisted deposition (PIAD) has been used; the high-reflective enhanced Ag-coating on the backside has been deposited by magnetron sputtering. The SWIR spectrometer contains four plane and spherical gold-coated mirrors, respectively, and two curved FS prisms with a broadband antireflection coating. Details about the ultra-precise manufacturing of metal mirrors and prisms as well as their coating are presented in this work.

  18. FUNCTIONALLY GRADED ALUMINA/MULLITE COATINGS FOR PROTECTION OF SILICON CARBIDE CERAMIC COMPONENTS FROM CORROSION

    SciTech Connect

    1998-03-01

    The main objective of this research project is the formulation of processes that can be used to prepare compositionally graded alumina/mullite coatings for protection from corrosion of silicon carbide components (monolithic or composite) used or proposed to be used in coal utilization systems (e.g., combustion chamber liners, heat exchanger tubes, particulate removal filters, and turbine components) and other energy-related applications. Mullite will be employed as the inner (base) layer and the composition of the film will be continuously changed to a layer of pure alumina, which will function as the actual protective coating of the component. Chemical vapor deposition reactions of silica, alumina, and aluminosilicates (mullite) through hydrolysis of aluminum and silicon chlorides in the presence of CO{sub 2} and H{sub 2} will be employed to deposit compositionally graded films of mullite and alumina. Our studies will include the kinetic investigation of the silica, alumina, and aluminosilicate deposition processes, characterization of the composition, microstructure, surface morphology, and mechanical behavior of the prepared films, and modeling of the various deposition processes. During this reporting period, the construction and development of the chemical vapor deposition system was completed, and experiments were conducted on the deposition of alumina, silica, and aluminosilicates (such as mullite) from mixtures of AlCl{sub 3} and CH{sub 3}SiCl{sub 3} in CO{sub 2} and H{sub 2}. Work was mainly done on the investigation of the effects of the reaction temperature on the deposition kinetics. It was found that the temperature had a positive effect on the single oxides deposition rates and the codeposition rate. The apparent activation energy values extracted from the deposition rate vs. temperature curves in the high temperature region were similar for the three deposition processes, having a value around 20 kcal/mol. The codeposition rates were higher, by a

  19. Radiofrequency-sputtered coatings for lubrication system components and other complex surfaces

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1972-01-01

    Irregularly shaped surfaces, such as lubrication system components (ball bearings, seals, gears, etc.), can be coated on all surfaces, including irregular shapes, when radiofrequency sputtering is used. When the specimen is properly located with respect to the sputtering target, the sputtered material covers the entire surface of the object irrespective of its geometrical configuration. An adherent, dense film is formed. The film thickness varies from 20 to 50 percent on, for example, a hearing cage or race depending on its geometry. When sputtered solid film lubricants such as molybdenum disulfide are used, a film thickness only of the order of 10 to the minus 7th power m (thousands of angstroms) is required at the contacting areas. It is only essential to determine the required film thickness at the critical areas in need of lubrication. The sections outside the areas to be lubricated fall within the thickness deviation range of 20 to 50 percent, which still constitutes a negligible change respect to tolerance requirements.

  20. Development and Evaluation of Processes for Deposition of Ni/Co-Cr-Aly (MCrAly) Coatings for Gas Turbine Components.

    DTIC Science & Technology

    1979-09-01

    turbine engines demand increasingly higher operating tem- peratures in blades and vanes for greater thrust and efficiency. The turbine components...limitations; namely, expense and the inability to uniformly coat complex geometries and clustered turbine blade and vane airfoils . Thus, another means of...cost and the ability to uniformly coat turbine components of complex geometries and clustered turbine blade and vane airfoils .

  1. FUNCTIONALY GRADED ALUMINA/MULLITE COATINGS FOR PROTECTION OF SILICON CARBIDE CERAMIC COMPONENTS FROM CORROSION

    SciTech Connect

    PROF. STRATIS V. SOTIRCHOS

    1998-10-01

    The main objective of this research project is the formulation of processes that can be used to prepare compositionally graded alumina/mullite coatings for protection from corrosion of silicon carbide components (monolithic or composite) used or proposed to be used in coal utilization systems (e.g., combustion chamber liners, heat exchanger tubes, particulate removal filters, and turbine components) and other energy-related applications. Mullite will be employed as the inner (base) layer and the composition of the film will be continuously changed to a layer of pure alumina, which will function as the actual protective coating of the component. Chemical vapor deposition reactions of silica, alumina, and aluminosilicates (mullite) through hydrolysis of aluminum and silicon chlorides in the presence of CO2 and H2 will be employed to deposit compositionally graded films of mullite and alumina. Our studies will include the kinetic investigation of the silica, alumina, and aluminosilicate deposition processes, characterization of the composition, microstructure, surface morphology, and mechanical behavior of the prepared films, and modeling of the various deposition processes. During this six-month reporting period, the experimental work on the investigation of the deposition of alumina, silica, and aluminosilicates from mixtures of methyltrichlorosilane (MTS), aluminum trichloride, carbon dioxide, and hydrogen was continued. Experiments were also conducted on the deposition processes of the simple oxides, alumina and silica, from mixtures containing only one chloride (AlCl3 and MTS, respectively). Deposition rate data were obtained in a relatively broad range of operating conditions: temperatures in the range 800-1000 o C, 100 Torr pressure, 0.006-0.015 AlCl3 feed mole fraction, 0.011- 0.027 CH3SiCl3 feed mole fraction, and 0.004-0.07 CO2 feed mole fraction, and various positions along the axis of the deposition reactor. Since the effect of temperature had been

  2. Deposition of Wear and Corrosion Resistant Coatings onto Landing Gear Components Via Directed Vapor Deposition

    DTIC Science & Technology

    2007-01-01

    Multilayer coatings • Combinatorial synthesis • Reactive deposition of oxides and nitrides • Supersonic gas jet focuses vapor flux onto substrate...velocity oxy -fuel (HVOF) process cannot be used. 3) Demonstrate that the coating is viable for sealing surfaces, where a surface finish of 8 to 12 micro

  3. Ceramic-coated components for the combustion zone of natural gas engines

    NASA Astrophysics Data System (ADS)

    Holloman, L.; Levy, A. V.

    1992-03-01

    The use of ceramic coatings on the combustion zone surfaces of large,natural gas-fueled,internal com-bustion engines is discussed. Unique handling and quality control systems are required for plasma spray-ing thin (0.25 mm,0.0010) in.coatings on up to 48.25(cm19)-in.diameter piston crowns and cylinder heads weighing up to(1200 lb).The in-service performance characteristics of two types of natural gas-fu-eled combustion engines powering natural gas compressors that had thin zirconia ceramic coatings ap-plied to their combustion zone surfaces are presented. Their performance was measured in the field be-fore and after coating. It was determined that the durability,power output,fuel consumption,exhaust emissions,and other operating characteristics all improved due to ceramic coating of the flame side sur-faces of cylinder heads,power pistons,and valves.

  4. Hydroxyapatite (HA) coating appears to be of benefit for implant durability of tibial components in primary total knee arthroplasty

    PubMed Central

    2011-01-01

    Background It is unclear whether there is a clinical benefit to adding hydroxyapatite (HA) coatings to total knee implants, especially with the tibial component, where failure of the implant more often occurs. A systematic review of the literature was undertaken to identify all prospective randomized trials for determining whether the overall clinical results (as a function of durability, function, and adverse events) favored HA-coated tibial components. Methods A comprehensive literature search was performed for the years 1990 to September 16, 2010. We restricted our search to randomized controlled trials involving participants receiving either an HA-coated tibia or other forms of tibial fixation. The primary outcome measures evaluated were durability, function, and acute adverse events. Results Data from 926 evaluable primary total knee implants in 14 studies were analyzed. Using an RSA definition for durability, HA-coated tibial components (porous or press-fit) without screw fixation were less likely to be unstable at 2 years than porous and cemented metal-backed tibial components (RR = 0.58, 95% CI: 0.34–0.98; p = 0.04, I2 = 39%, M-H random effects model). There was no significant difference in durability, as measured from revision and evaluated at 2 and 8–10 years, between groups. Also, functional status using different validated measures showed no significant difference at 2 and 5 years, no matter what measure was used. Lastly, there was no significant difference in adverse events. Limitations included small numbers of evaluable patients (≤ 50) in 7 of the 14 trials identified, and a lack of “hard” evidence of durability with need for replacement (i.e. frank failure, pain, or loss of functionality). Interpretation In patients > 65 years of age, an HA-coated tibial implant may provide better durability than other forms of tibial fixation. Larger trials should be undertaken comparing the long-term durability, function, and adverse events of HA-coated

  5. Hydroxyapatite (HA) coating appears to be of benefit for implant durability of tibial components in primary total knee arthroplasty.

    PubMed

    Voigt, Jeffrey D; Mosier, Michael

    2011-08-01

    It is unclear whether there is a clinical benefit to adding hydroxyapatite (HA) coatings to total knee implants, especially with the tibial component, where failure of the implant more often occurs. A systematic review of the literature was undertaken to identify all prospective randomized trials for determining whether the overall clinical results (as a function of durability, function, and adverse events) favored HA-coated tibial components. A comprehensive literature search was performed for the years 1990 to September 16, 2010. We restricted our search to randomized controlled trials involving participants receiving either an HA-coated tibia or other forms of tibial fixation. The primary outcome measures evaluated were durability, function, and acute adverse events. Data from 926 evaluable primary total knee implants in 14 studies were analyzed. Using an RSA definition for durability, HA-coated tibial components (porous or press-fit) without screw fixation were less likely to be unstable at 2 years than porous and cemented metal-backed tibial components (RR = 0.58, 95% CI: 0.34-0.98; p = 0.04, I(2) = 39%, M-H random effects model). There was no significant difference in durability, as measured from revision and evaluated at 2 and 8-10 years, between groups. Also, functional status using different validated measures showed no significant difference at 2 and 5 years, no matter what measure was used. Lastly, there was no significant difference in adverse events. Limitations included small numbers of evaluable patients (≤ 50) in 7 of the 14 trials identified, and a lack of "hard" evidence of durability with need for replacement (i.e. frank failure, pain, or loss of functionality). In patients > 65 years of age, an HA-coated tibial implant may provide better durability than other forms of tibial fixation. Larger trials should be undertaken comparing the long-term durability, function, and adverse events of HA-coated implants with those of other porous-coated

  6. Electron Transport in Plasmas with Lithium-Coated Plasma-Facing Components

    SciTech Connect

    Jacobson, Craig

    2014-04-01

    The Lithium Tokamak Experiment (LTX) is a spherical tokamak designed to study the low-recycling regime through the use of lithium-coated shells conformal to the last closed flux surface (LCFS). A lowered recycling rate is expected to flatten core $T_\\mathrm{e}$ profiles, raise edge $T_\\mathrm{e}$, strongly affect $n_\\mathrm{e}$ profiles, and enhance confinement. To study these unique plasmas, a Thomson scattering diagnostic uses a $\\le 20$~J, 30~ns FWHM pulsed ruby laser to measure $T_\\mathrm{e}$ and $n_\\mathrm{e}$ at 11 radial points on the horizontal midplane, spaced from the magnetic axis to the outer edge at a single temporal point for each discharge. Scattered light is imaged through a spectrometer onto an intensified CCD. The diagnostic is absolutely calibrated using a precision light source and Raman scattering. Measurements of $n_\\mathrm{e}$ are compared with line integrated density measurements from a microwave interferometer. Adequate signal to noise is obtained with $n_\\mathrm{e} \\ge 2 \\times 10^{18}\\,\\mathrm{m^{-3}}$. Thomson profiles of plasmas following evaporation of lithium onto room-temperature plasma-facing components (PFCs) are used in conjunction with magnetic equilibria as input for TRANSP modeling runs. Neoclassical calculations are used to determine $T_\\mathrm{i}$ profiles, which have levels that agree with passive charge exchange recombination spectroscopy (CHERS) measurements. TRANSP results for confinement times and stored energies agree with diamagnetic loop measurements. Results of $\\chi_\\mathrm{e}$ result in values as low as 7 m$^2$/s near the core, which rise to around 100 m$^2$/s near the edge. These are the first measurements of $\\chi_\\mathrm{e}$ in LTX, or its predecessor, the Current Drive Experiment-Upgrade (CDX-U), with lithium PFCs.

  7. Functionalization of PDMS modified and plasma activated two-component polyurethane coatings by surface attachment of enzymes

    NASA Astrophysics Data System (ADS)

    Kreider, Alexej; Richter, Katharina; Sell, Stephan; Fenske, Mandus; Tornow, Christian; Stenzel, Volkmar; Grunwald, Ingo

    2013-05-01

    This article describes a new strategy for coupling the enzyme horseradish peroxidase to a two-component polyurethane (2C-PUR) coating. A stable polymer conjugate was achieved by combining the enzyme and the 2C-PUR coating which was modified with poly(dimethylsiloxane) (PDMS), located at the surface. An atmospheric pressure plasma jet system was used to convert alkyl groups from the PDMS into polar silanol functionalities. This conversion was proven by X-ray photoelectron spectroscopy and dynamic contact angle measurements. In addition, the stability of the activated 2C-PUR surface containing silanol groups was determined by measuring the contact angle as a function of time. Compared to the non-modified 2C-PUR systems the one with PDMS displayed a higher stability over a time period over 28 h. In a silanization process the coating was treated with (3-aminopropyl) trimethoxysilane and the enzyme was subsequently immobilized to the coating via the cross linker glutaraldehyde to receive new biomimetic catalytic/enzymatic functions. The chemical immobilization (chemisorption) of the enzyme to the surface showed statistically significant higher biological activity as compared to references samples without using a cross linker (physisorption). The presented technique offers the opportunity to design new and smart multifunctional surface coatings which employ biomimetic capabilities.

  8. Development of oxide based diffusion barrier coatings for CFC components applied in modern furnaces

    NASA Astrophysics Data System (ADS)

    Bobzin, Kirsten; Zhao, Lidong; Schlaefer, Thomas; Warda, Thomas

    2011-12-01

    Carbon fibre reinforced carbon (CFC) materials show a high potential for usage in furnaces as sample carriers for example, which is due to their excellent thermal stability compared to steel carriers. Only their tendency to react with different metals at high temperatures by Cdiffusion is a disadvantage, which can be solved by application of diffusion barriers. In order to enable the utilization of CFC-carriers for e.g. brazing furnaces, within the frame of this study thermally sprayed diffusion barrier coatings were developed. Coatings of mullite and ZrO2-7% Y2O3 (YSZ) were prepared by air plasma spraying (APS). The coatings were investigated in terms of their microstructure and thermal shock behaviour. In order to prove the suitability of the coatings for the application in brazing furnaces, the wettability of the coating surfaces by a Ni-based brazing alloy was investigated. The results showed that both mullite and YSZ could be deposited on CFC substrates with a bond coat of W or SiC. Both coatings exhibited good thermal shock behaviour and an excellent non-wetting behaviour against the used Ni-based braze alloy.

  9. Development of ion-plated aluminide diffusion coatings for thermal cyclic oxidation and hot corrosion protection of a nickel-based superalloy and a stainless steel

    NASA Astrophysics Data System (ADS)

    Elsawy, Abdel Raouf

    This project was carried out at the University of Toronto and Cametoid Ltd of Whitby, Ontario. Ohno continuous casting; a novel net shape casting technique, was used to generate, Al-Y, Al-Ce, Al-La, and Al-Si-Y, in form of 1.6 to 1.7 mm diameter alloy wires. These alloy wires exhibited suitable properties for use as feed materials to an Ion Vapor Deposition facility. The deposition parameters were optimized to provide coatings with a compact and cohesive columnar structure with reduced porosity and diffusion barriers that were essential to ensure the success of the diffusion process in the subsequent stage. Solid-state diffusion heat treatment processes were developed in order to form the stable aluminide phases, AlNi and FeAl, on IN738 and S310 substrates, respectively. Experiments simulating the coating service conditions and environments encountered during the prospective aerospace and fuel cell applications were conducted to evaluate the performance of each aluminide coating developed during this study. Thermal cyclic oxidation and molten sulfate corrosion studies were performed on coated IN738 pins at 1050°C and 900°C, respectively, simulating the service environment of turbine engine blades and other hot section components. Molten carbonate corrosion behavior was investigated for coated S310 coupons that were immersed in, or covered with a thin film of molten carbonate, at 650°C, in air plus 30%CO2, to simulate the operating conditions of the cathode-side separator plates of molten carbonate fuel cells. The behavior of the reactive elements, yttrium, cerium, lanthanum, and silicon in enhancing the adhesion of the protective aluminum oxide scale was determined by weight variation experiments, structural examination and compositional analysis. The influence of the base material elements, nickel, chromium, and iron, on the formation of protective oxides was investigated. All coatings were found to provide significant improvement for thermal cyclic oxidation

  10. Manufacturing Techniques for Application of Erosion Resistant Coatings to Turbine Engine Compressor Components.

    DTIC Science & Technology

    these systems for 403 stainless steel and AM355 production hardware was undertaken. The program was divided into three phases: Coating optimization; Process scale-up; and Engine qualification and environmental tests. (Author)

  11. Boron carbide-based coatings on graphite for plasma facing components

    SciTech Connect

    Valentine, P.G.; Trester, P.W.; Winter, J.; Linke, J.; Duwe, R.; Wallura, E.; Philipps, V.

    1994-01-01

    In the effort to evaluate boron-rich coatings as plasma facing surfaces in fusion devices, a new process for applying boron carbide (B{sub 4}C) coatings to graphite was developed. The process entails eutectic melting of the carbon (C) substrate surface with a precursor layer of B{sub 4}C particles. Adherent coatings were achieved which consisted of two layers: a surface layer and a graded penetration zone in the outer portion of the substrate. The surface-layer microstructure was multiphase and ranged from reaction-sintered structures of sintered B{sub 4}C particles in an eutectic-formed matrix to that of hypereutectic carbon particles in a B{sub 4}C-C eutectic matrix. Because of high surface energy, the coating generally developed a nonuniform thickness. Quantitative evaluations of the coating were performed with limiters in the TEXTOR fusion device and with coupons in electron beam tests. Test results revealed the following: good adherence of the coating even after remelting; and, during remelting, diagnostics detected a corresponding interaction of boron with the plasma.

  12. Whole blood treated with riboflavin and ultraviolet light: quality assessment of all blood components produced by the buffy coat method.

    PubMed

    Schubert, Peter; Culibrk, Brankica; Karwal, Simrath; Serrano, Katherine; Levin, Elena; Bu, Daniel; Bhakta, Varsha; Sheffield, William P; Goodrich, Raymond P; Devine, Dana V

    2015-04-01

    Pathogen inactivation (PI) technologies are currently licensed for use with platelet (PLT) and plasma components. Treatment of whole blood (WB) would be of benefit to the blood banking community by saving time and costs compared to individual component treatment. However, no paired, pool-and-split study directly assessing the impact of WB PI on the subsequently produced components has yet been reported. In a "pool-and-split" study, WB either was treated with riboflavin and ultraviolet (UV) light or was kept untreated as control. The buffy coat (BC) method produced plasma, PLT, and red blood cell (RBC) components. PLT units arising from the untreated WB study arm were treated with riboflavin and UV light on day of production and compared to PLT concentrates (PCs) produced from the treated WB units. A panel of common in vitro variables for the three types of components was used to monitor quality throughout their respective storage periods. PCs derived from the WB PI treatment were of significantly better quality than treated PLT components for most variables. RBCs produced from the WB treatment deteriorated earlier during storage than untreated units. Plasma components showed a 3% to 44% loss in activity for several clotting factors. Treatment of WB with riboflavin and UV before production of components by the BC method shows a negative impact on all three blood components. PLT units produced from PI-treated WB exhibited less damage compared to PLT component treatment. © 2014 AABB.

  13. Influence of surface-energy components of Ni-P-TiO2-PTFE nanocomposite coatings on bacterial adhesion.

    PubMed

    Liu, Chen; Zhao, Qi

    2011-08-02

    The influence of total surface energy on bacterial adhesion has been investigated intensively with the frequent conclusion that bacterial adhesion is less on low-energy surfaces. However, there are also a number of contrary findings that high-energy surfaces have a smaller biofouling tendency. Recently, it was found that the CQ ratio, which is defined as the ratio of Lifshitz-van der Waals (LW) apolar to electron donor surface-energy components of substrates, has a strong correlation to bacterial adhesion. However, the electron donor surface-energy components of substrates varied over only a very limited range. In this article, a series of Ni-P-TiO(2)-PTFE nanocomposite coatings with wide range of surface-energy components were prepared using an electroless plating technique. The bacterial adhesion and removal on the coatings were evaluated with different bacteria under both static and flow conditions. The experimental results demonstrated that there was a strong correlation between bacterial attachment (or removal) and the CQ ratio. The coatings with the lowest CQ ratio had the lowest bacterial adhesion or the highest bacterial removal, which was explained using the extented DLVO theory.

  14. Thick Thermal Barrier Coatings (TTBCs) for Low Emission, High Efficiency Diesel Engine Components

    SciTech Connect

    M. Brad Beardsley, Caterpillar Inc.; Dr. Darrell Socie, University of Illinois; Dr. Ed Redja, University of Illinois; Dr. Christopher Berndt, State University of New York at Stony Brook

    2006-03-02

    The objective of this program was to advance the fundamental understanding of thick thermal barrier coating (TTBC) systems for application to low heat rejection diesel engine combustion chambers. Previous reviews of thermal barrier coating technology concluded that the current level of understanding of coating system behavior is inadequate and the lack of fundamental understanding may impede the application of thermal barrier coating to diesel engines.(1) Areas of TTBC technology examined in this program include powder characteristics and chemistry; bond coating composition, coating design, microstructure and thickness as they affect properties, durability, and reliability; and TTBC "aging" effects (microstructural and property changes) under diesel engine operating conditions. Fifteen TTBC ceramic powders were evaluated. These powders were selected to investigate the effects of different chemistries, different manufacturing methods, lot-to-lot variations, different suppliers and varying impurity levels. Each of the fifteen materials has been sprayed using 36 parameters selected by a design of experiments (DOE) to determine the effects of primary gas (Ar and N2), primary gas flow rate, voltage, arc current, powder feed rate, carrier gas flow rate, and spraying distance. The deposition efficiency, density, and thermal conductivity of the resulting coatings were measured. A coating with a high deposition efficiency and low thermal conductivity is desired from an economic standpoint. An optimum combination of thermal conductivity and disposition efficiency was found for each lot of powder in follow-on experiments and disposition parameters were chosen for full characterization.(2) Strengths of the optimized coatings were determined using 4-point bending specimens. The tensile strength was determined using free-standing coatings made by spraying onto mild steel substrates which were subsequently removed by chemical etching. The compressive strengths of the coatings

  15. Facile Synthesis of Smart Nanocontainers as Key Components for Construction of Self-Healing Coating with Superhydrophobic Surfaces

    NASA Astrophysics Data System (ADS)

    Liang, Yi; Wang, MingDong; Wang, Cheng; Feng, Jing; Li, JianSheng; Wang, LianJun; Fu, JiaJun

    2016-04-01

    SiO2-imidazoline nanocomposites (SiO2-IMI) owning high loading capacity of corrosion inhibitor, 1-hexadecyl-3-methylimidazolium bromide (HMID), and a special acid/alkali dual-stimuli-accelerated release property have been synthesized via a one-step modified Stöber method. SiO2-IMI were uniformly distributed into the hydrophobic SiO2 sol to construct "host"-"guest" feedback active coating with a superhydrophobic surface (SiO2-IMI@SHSC) on aluminium alloy, AA2024, by dip-coating technique. SiO2-IMI as "guest" components have good compatibility with "host" sol-gel coating, and more importantly, once localized corrosion occurs on the surface of AA2024, SiO2-IMI can simultaneously respond to the increase in environmental pH around corrosive micro-cathodic regions and decrease in pH near micro-anodic regions, promptly releasing HMID to form a compact molecular film on the damaged surface, inhibiting corrosion spread and executing a self-healing function. The scanning vibrating electrode technique (SVET) was applied to illustrate the suppression process of cathodic/anodic corrosion activities. Furthermore, benefiting from the superhydrophobic surface, SiO2-IMI@SHSC remained its protective ability after immersion in 0.5 M NaCl solution for 35 days, which is far superior to the conventional sol-gel coating with the same coating thickness. The facile fabrication method of SiO2-IMI simplifies the construction procedure of SiO2-IMI@SHSC, which have great potential to replace non-environmental chromate conversion coatings for practical use.

  16. Phase of Photothermal Emission Analysis as a Diagnostic Tool for Thermal Barrier Coatings on Serviceable Engine Components

    NASA Astrophysics Data System (ADS)

    Kakuda, Tyler

    Power generation and aircraft companies are continuously improving the efficiency of gas turbines to meet economic and environmental goals. The trend towards higher efficiency has been achieved in part by raising the operating temperature of engines. At elevated temperatures, engine components are subject to many forms of degradation including oxidation, creep deformation and thermal cycle fatigue. To minimize these harmful effects, ceramic thermal barrier coatings (TBCs) are routinely used to insulate metal components from excessive heat loads. Efforts to make realistic performance assessments of current and candidate coating materials has led to a diverse battery of creative measurement techniques. While it is unrealistic to envision a single measurement that would provide all conceivable information about the TBC, it is arguable that the capability for the single most important measurement is still lacking. A quantitative and nondestructive measurement of the thermal protection offered by a coating is not currently among the measurements one can employ on a serviceable engine part (or even many experimental specimens). In this contribution, phase of photothermal emission analysis (PopTea) is presented as a viable thermal property measurement for serviceable engine components. As it will be shown, PopTea has the versatility to make measurements on gas turbine parts in situ, with the goal of monitoring TBCs over the lifetime of the engine. The main challenges toward this goal are dealing with changes that occur to the TBC during service. Several of the main degradations seen on engine equipment include: aging, surface contamination and infiltration of foreign deposits. Measuring coatings under these conditions, is the impetus of this work. Furthermore, it is demonstrated that PopTea can be used on real engine equipment with measurements made on an actual turbine blade.

  17. Edge transport and turbulence reduction with lithium coated plasma facing components in the National Spherical Torus Experiment

    SciTech Connect

    Canik, J. M.; Maingi, R.; Kubota, S.; Ren, Y.; Bell, R. E.; Guttenfelder, W.; Kugel, H. W.; LeBlanc, B. P.; Callen, J. D.; Osborne, T. H.; Soukhanovskii, V. A.

    2011-05-15

    The coating of plasma facing components (PFCs) with lithium improves energy confinement and eliminates ELMs in the National Spherical Torus Experiment, the latter due to a relaxation of the density and pressure profiles that reduces the drive for peeling-ballooning modes. 2-D interpretive transport modeling of discharges without and with lithium shows that a reduction in the PFC recycling coefficient from R {approx} 0.98 to R {approx} 0.90 is required to match the drop in D{sub {alpha}} emission with lithium coatings. A broadening of the edge barrier region showing reduced transport coefficients is observed, with a {approx}75% drop of the D and {chi}{sub e} from 0.8 < {psi}{sub N} < 0.93 needed to match the profile relaxation with lithium coatings. Turbulence measurements using an edge reflectometry system as well as high-k microwave scattering show a decrease in density fluctuations with lithium coatings. These transport changes allow the realization of very wide pedestals, with a {approx}100% width increase relative to the reference discharges.

  18. Bone ingrowth and wear debris in well-fixed cementless porous-coated tibial components removed from patients.

    PubMed

    Sumner, D R; Kienapfel, H; Jacobs, J J; Urban, R M; Turner, T M; Galante, J O

    1995-04-01

    Bone ingrowth and the distribution of wear debris within the porous coating of 13 primary cementless porous-coated tibial components removed for reasons unrelated to fixation or infection were quantitatively described. The average length of implantation was 15.3 months (range, 3-30 months). The implants were all of the same design, made for Ti6A14V with a commercially pure titanium fiber-metal porous coating, which covered the undersurface of the tray and the four fixation pegs. In all but one component, supplemental screw fixation was used. The average extent of bone ingrowth within the tray was 27.1 +/- 16.1%, and the average volume fraction was 9.5 +/- 7.5%. There was significantly more bone ingrowth within the fixation pegs than within the tray and also more bone ingrowth in the anterior half of the tray than posteriorly. There was no correlation between the amount of bone ingrowth and the length of implantation, age, or sex of the patient; however, the depth and orientation of the resection plane were found to correlate with the topographic distribution of bone ingrowth. Particulate debris appeared to gain access to the interface via soft tissue pathways both at the periphery and through the holes for adjuvant screw fixation.

  19. Agglutination of Jelly Coat and Cortical Granule Components and the Block to Polyspermy in the Amphibian Xenopus laevis

    PubMed Central

    Wyrick, Ron E.; Nishihara, Tatsuro; Hedrick, Jerry L.

    1974-01-01

    A block to polyspermy in amphibians is established at fertilization by the conversion of the vitelline envelope to the fertilization envelope. In Xenopus laevis a major ultrastructural change in the envelope at fertilization is the appearance of an electron-dense layer, termed the F layer, between the envelope and the inner-most jelly coat layer, J1. The F layer is derived, at least in part, from materials released from the cortical granules. Further definition of the origin and chemical nature of the F layer was sought by using isolated cortical granule (CG) exudate and jelly coat layer J1. In double diffusion experiments, the isolated components interacted in an agglutination reaction producing a band of precipitation. The agglutination involved α-galactoside residues and metal ions (Ca++). Employing chemically modified jelly, we demonstrated that sulfhydryl-disulfide interchanges were not involved in the agglutination and, with 35S-labeled jelly, that the agglutinating J1 component possessed sulfate esters. Both the CG exudate and the J1 components contained carbohydrate, as evidenced by their lectin reactivity. A number of ionic polymers, both natural and synthetic, were tested as chemical analogs of CG exudate and J1; none gave an agglutination band. Dissolved jelly coat material from eggs of two different species of frogs agglutinated with CG exudate, while jelly from sea urchin eggs and hyaluronic acid from mammalian eggs did not. Thus, the agglutination reaction was chemically and phylogenetically specific. An electron-dense layer, similar to the F layer, formed on the outer of the vitelline envelope when jellied unfertilized eggs were immersed in CG exudate; such eggs were not fertilizable. We suggest that in Xenopus laevis, and perhaps other organisms as well, an agglutination type of reaction between cortical granule components and egg integuments is a participant in the structural and molecular events establishing a block to polyspermy. Images PMID

  20. Development of wear-resistant ceramic coatings for diesel engine components

    SciTech Connect

    Naylor, M.G.S. )

    1992-06-01

    The tribological properties of a variety of advanced coating materials have been evaluated under conditions which simulate the piston ring -- cylinder liner environment near top ring reversal in a heavy duty diesel engine. Coated ring'' samples were tested against a conventional pearlitic grey cast iron liner material using a high temperature reciprocating wear test rig. Tests were run with a fresh CE/SF 15W40lubricant at 200 and 350{degrees}C, with a high-soot, engine-tested oil at 200{degrees}C and with no lubrication at 200{degrees}C. For lowest wear under boundary lubricated conditions, the most promising candidates to emerge from this study were high velocity oxy-fuel (HVOF) Cr{sub 3} C{sub 2} - 20% NiCr and WC - 12% Co cermets, low temperature arc vapor deposited (LTAVD) CrN and plasma sprayed chromium oxides. Also,plasma sprayed Cr{sub 2}O{sub 3} and A1{sub 2}O{sub 3}-ZrO{sub 2} materials were found to give excellent wear resistance in unlubricated tests and at extremely high temperatures (450{degrees}C) with a syntheticoil. All of these materials would offer substantial wear reductions compared to the conventional electroplated hard chromium ring facing and thermally sprayed metallic coatings, especially at high temperatures and with high-soot oils subjected to degradation in diesel environments. The LTAVD CrN coating provided the lowest lubricated wear rates of all the materials evaluated, but may be too thin (4 {mu}m) for use as a top ring facing. Most of the coatings evaluated showed higher wear rates with high-soot, engine-tested oil than with fresh oil, with increases of more than a factor of ten in some cases. Generally, metallic materials were found to be much more sensitive to soot/oil degradation than ceramic and cermet coatings. Thus, decreased soot sensitivity'' is a significant driving force for utilizing ceramic or cermet coatings in diesel engine wear applications.

  1. Functionally Graded Alumina/Mullite Coatings for Protection of Silicon Carbide Ceramic Components from Corrosion

    SciTech Connect

    Sotirchos, S.V.

    1997-04-01

    During the six months of this reporting period, we accomplished the following: Preparatory work was done on the development of the feed supply system (for mixtures of AlCl{sub 3}, SiCl{sub 4}, H{sub 2} and CO{sub 2}) and effluent treatment section for the CVD system we plan to employ for coating preparation. A comprehensive literature survey of past work done on the chemical vapor deposition of silica, alumina and aluminosilicates (mullite) was carried out, and work was initiated on the study of thermochemical equilibrium in the Al/Si/Cl/C/O/H system so as to identify the boundaries of the region of the space of operating parameters and conditions where preparation of functionally graded mullite/ alumina coatings through CVD from metal chloride, CO{sub 2}, and H{sub 2} is feasible. Since the alumina/mullite films that are proposed to be developed can also be applied to carbon matrix composites provided that a layer that bridges the gap that exists between the thermal expansion coefficient of carbon and that of mullite is employed, experiments were conducted on the preparation of compositionally graded carbon/silicon carbide coatings. Deposition from mixtures of ethylene and methyltrichlorosilane or tetrachlorosilane (silicon tetrachloride) in hydrogen was used for the preparation of SiC/C coatings, and our experiments focused on the study of the occurrence of multiple steady states in the deposition process and the effects of the type of chlorosilane on the deposition rate and the deposit composition and their variation along the length of the reactor. The results showed that when operation is carried out outside the multiplicity region, codeposition of SiC and C from ethylene and chlorosilanes is a feasible route for preparation of SiC/C graded coatings.

  2. Analysis of failed and nickel-coated 3093 beam clamp components at the East Tennessee Technology Park (ETTP).

    SciTech Connect

    Singh, D.; Pappacena, K.; Gaviria, J.; Burtsteva, T.; Nuclear Engineering Division

    2010-10-11

    was also explored as a failure mechanism. Corroded and failed yoke samples had hydrogen concentrations of 20-60 ppm. However, the hydrogen content reduced to 4-11 ppm (similar to baseline as-received yoke samples) when the corrosion products were polished off. The hydrogen content in the scraped off corrosion product powders was >7000 ppm. These results indicate that hydrogen is primarily present in the corrosion products and not in the underlying steel. Rockwell hardness values on the corroded yoke and D-rings were R{sub c} {approx} 41-46. It was recommended to the beam clamp manufacturer that the beam clamp components be annealed to reduce the hardness values so that they are less susceptible to brittle failure. Upon annealing, hardness values of the beam clamp components reduced to R{sub c} {approx} 25. Several strategies were recommended and put in place to mitigate failure of the beam clamp components: (a) maintain hardness levels of both yokes and D-rings at R{sub c} < 35, (b) coat the yoke and D-rings with a dual coating of nickel (with 10% phosphorus) to delay corrosion and aluminum to prevent galvanic corrosion since it is more anodic to zinc, and (c) optimize coating thicknesses for nickel and aluminum while maintaining the physical integrity of the coatings. Evaluation of the Al- and Ni-coated yoke and D-ring specimens indicated they appear to have met the recommendations. Average hardness values of the dual-coated yokes were R{sub c} {approx} 25-35. Hardness values of dual-coated D-ring were R{sub c} {approx} 32. Measured average coating thicknesses for the aluminum and nickel coatings for yoke samples were 22 {micro}m (0.9 mils) and 80 {micro}m (3 mils), respectively. The D-rings also showed similar coating thicknesses. Microscopic examination showed that the aluminum coating was well bonded to the underlying nickel coating. Some observed damage was believed to be an artifact of the cutting-and-polishing steps during sample preparation for microscopy.

  3. Optimizing thermally grown oxide for thermal barrier coatings on TiAl components via fluorine treatment

    NASA Astrophysics Data System (ADS)

    Donchev, A.; Braun, R.; Schütze, M.

    2010-01-01

    Titanium aluminides suffer from non-protective mixed-oxide scale formation during high-temperature exposure in oxidizing environments, so that they cannot be used at temperatures above approximately 800° C for longer times without additional treatment. A fluorine treatment on γ-TiAl alloys leads to the formation of a pure protective alumina scale and allows their use at service temperatures above 800°C. This thermally grown aluminum oxide layer can be used for bonding ceramic thermal barrier coatings to the TiAl substrate. Zirconia topcoats deposited by electron-beam physical vapor deposition were very adherent to F-treated TiA samples during cyclic oxidation tests at 900 to 1,000°C. A separate bond coat is not needed in this case.

  4. Replacement of Chromium Electroplating on Gas Turbine Engine Components Using Thermal Spray Coatings

    DTIC Science & Technology

    2007-11-02

    Military Specifications: MIL-H-6875: Heat Treatment of 4340 Steel MIL-STD-1501: Chromium Plating Low Embrittlement , Electrodeposition MIL-STD-866...characteristics such as corrosion, wear, hydrogen embrittlement , etc. but coating optimization initially concentrated on fatigue performance, with...375 °F ± 25 °F within four hours after plating for a total of 24 hours prior to grinding to final dimension for hydrogen embrittlement relief and to

  5. Hydroxyapatite nanocrystals functionalized with alendronate as bioactive components for bone implant coatings to decrease osteoclastic activity

    NASA Astrophysics Data System (ADS)

    Bosco, Ruggero; Iafisco, Michele; Tampieri, Anna; Jansen, John A.; Leeuwenburgh, Sander C. G.; van den Beucken, Jeroen J. J. P.

    2015-02-01

    The integration of bone implants within native bone tissue depends on periprosthetic bone quality, which is severely decreased in osteoporotic patients. In this work, we have synthesized bone-like hydroxyapatite nanocrystals (nHA) using an acid-base neutralization reaction and analysed their physicochemical properties. Subsequently, we have functionalized the nHA with alendronate (nHAALE), a well-known bisphosphonate drug used for the treatment of osteoporosis. An in vitro osteoclastogenesis test was carried out to evaluate the effect of nHAALE on the formation of osteoclast-like cells from monocytic precursor cells (i.e. RAW264.7 cell line) showing that nHAALE significantly promoted apoptosis of osteoclast-like cells. Subsequently, nHA and nHAALE were deposited on titanium disks using electrospray deposition (ESD), for which characterisation of the deposited coatings confirmed the presence of alendronate in nHAALE coatings with nanoscale thickness of about 700 nm. These results indicate that alendronate linked to hydroxyapatite nanocrystals has therapeutic potential and nHAALE can be considered as an appealing coating constituent material for orthopaedic and oral implants for application in osteoporotic patients.

  6. The effect of graphite components and crucible coating on the behaviour of carbon and oxygen in multicrystalline silicon

    NASA Astrophysics Data System (ADS)

    Raabe, Lutz; Pätzold, Olf; Kupka, Iven; Ehrig, Jan; Würzner, Sindy; Stelter, Michael

    2011-03-01

    In the present paper the effect of the furnace interior materials on the carbon and oxygen concentrations in multicrystalline silicon (mc-Si) is studied. Mc-Si ingots were produced in a high-vacuum induction furnace by means of the vertical Bridgman technique. Growth experiments with or without graphite components in the furnace as well as with crucible coatings of different oxygen concentrations were performed. The concentration of carbon monoxide in the growth chamber is found to depend significantly on the setup used. A standard, graphite-containing setup results in pronounced CO formation, which can be completely suppressed by applying graphite-free elements. Oxygen in the crucible coating is shown to influence the concentration of carbon monoxide via the formation of SiO. Growth under a CO enriched atmosphere is associated with the formation of a SiC/SiO2 melt surface layer, which pins the carbon concentration in the melt or crystal near its solubility limit, whereas in graphite- or CO-free growth the dissolved carbon segregates approximately according to Scheil's law. On the other hand, the effect of carbon monoxide on oxygen concentration in the grown crystals appears to be negligible. Instead, the oxygen concentration is directly related to the oxygen content of the crucible coating.

  7. Replacement of Chromium Electroplating on Landing Gear Components Using HVOF Thermal Spray Coatings

    DTIC Science & Technology

    2004-05-01

    Ogden Air Logistics Center • Mr. Robert Kestler, Naval Aviation Depot Cherry Point • Mr. James Candela, Naval Air Systems Command • Mr. Donald...WC/17Co or WC/10Co4Cr sliding against bushings fabricated from 4340 steel, Al-Ni bronze, anodized 2024 Al alloy, a Nitrile seal, or a Karon B seal...or a Karon B seal. The fretting test is illustrated in Figure 8, with the shoe fabricated from 4340 steel and coated with EHC, WC/17Co or WC

  8. Influence of dentifrices and dietary components in saliva on wettability of pellicle-coated enamel in vitro and in vivo.

    PubMed

    van der Mei, H C; White, D J; Kamminga-Rasker, H J; Knight, J; Baig, A A; Smit, J; Busscher, H J

    2002-12-01

    In vitro salivary pellicles were found to be less hydrophobic by water contact angles than clinically formed pellicles. In this study, water contact angles were measured on enamel coated with pellicles adsorbed from reconstituted human whole saliva (RHWS) and after exposure to dentifrices or dietary components. In addition, adhesion of Streptococcus oralis J22 to pellicles formed from RHWS with minor amounts of milk added and after exposure to dentifrices was studied. Exposure of RHWS-pellicles to milk or salad oil yielded an increase in the hydrophobicity of in vitro pellicles to values observed in vivo, but a decrease was seen after exposure to a sugar solution. Pellicles formed from saliva with 0.4% milk added attracted less S. oralis cells than pellicles formed in the absence of milk components. Exposure of pellicles formed from saliva with milk added to various dentifrices had a variable effect on bacterial adhesion: markedly lower numbers of adhering S. oralis were found for a dentifrice with NaF, but exposure to dentifrices containing SnF2 or hexametaphosphate showed slightly increased adhesion. In summary, dietary components have influence on the hydrophobicity of enamel pellicles, while combinations of dietary components and dentifrices certainly influence the adhesiveness of the pellicles. The effects of dietary components on pellicle conditioning film should be taken into consideration in research on the development of ingredients to control intraoral surface chemistry and microbiology, as well as in the development of oral products.

  9. Furnace Cyclic Behavior of Plasma-Sprayed Zirconia-Yttria and Multi-Component Rare Earth Oxide Doped Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Nesbitt, James A.; McCue, Terry R.; Barrett, Charles A.; Miller, Robert A.

    2002-01-01

    Ceramic thermal barrier coatings will play an increasingly important role in advanced gas turbine engines because of their ability to enable further increases in engine temperatures. However, the coating performance and durability become a major concern under the increasingly harsh thermal cycling conditions. Advanced zirconia- and hafnia-based cluster oxide thermal barrier coatings with lower thermal conductivity and improved thermal stability are being developed using a high-heat-flux laser-rig based test approach. Although the new composition coatings were not yet optimized for cyclic durability, an initial durability screening of numerous candidate coating materials was carried out using conventional furnace cyclic tests. In this paper, furnace thermal cyclic behavior of the advanced plasma-sprayed zirconia-yttria-based thermal barrier coatings that were co-doped with multi-component rare earth oxides was investigated at 1163 C using 45 min hot cycles. The ceramic coating failure mechanisms were studied by using scanning electron microscopy combined with X-ray diffraction phase analysis after the furnace tests. The coating cyclic lifetime will be discussed in relation to coating phase structures, total dopant concentrations, and other properties.

  10. Effect of Blood Component Coatings of Enosseal Implants on Proliferation and Synthetic Activity of Human Osteoblasts and Cytokine Production of Peripheral Blood Mononuclear Cells.

    PubMed

    Himmlova, Lucie; Kubies, Dana; Hulejova, Hana; Bartova, Jirina; Riedel, Tomas; Stikarova, Jana; Suttnar, Jiri; Pesakova, Vlasta

    2016-01-01

    The study monitored in vitro early response of connective tissue cells and immunocompetent cells to enosseal implant materials coated by different blood components (serum, activated plasma, and plasma/platelets) to evaluate human osteoblast proliferation and synthetic activity and inflammatory response presented as a cytokine profile of peripheral blood mononuclear cells (PBMCs) under conditions imitating the situation upon implantation. The cells were cultivated on coated Ti-plasma-sprayed (Ti-PS), Ti-etched (Ti-Etch), Ti-hydroxyapatite (Ti-HA), and ZrO2 surfaces. The plasma/platelets coating supported osteoblast proliferation only on osteoconductive Ti-HA and Ti-Etch whereas activated plasma enhanced proliferation on all surfaces. Differentiation (BAP) and IL-8 production remained unchanged or decreased irrespective of the coating and surface; only the serum and plasma/platelets-coated ZrO2 exhibited higher BAP and IL-8 expression. RANKL production increased on serum and activated plasma coatings. PBMCs produced especially cytokines playing role in inflammatory phase of wound healing, that is, IL-6, GRO-α, GRO, ENA-78, IL-8, GM-CSF, EGF, and MCP-1. Cytokine profiles were comparable for all tested surfaces; only ENA-78, IL-8, GM-CSF, and MCP-1 expression depended on materials and coatings. The activated plasma coating led to uniformed surfaces and represented a favorable treatment especially for bioinert Ti-PS and ZrO2 whereas all coatings had no distinctive effect on bioactive Ti-HA and Ti-Etch.

  11. Intraoperative type 1 proximal femoral fractures: influence on the stability of hydroxyapatite-coated femoral components.

    PubMed

    Falez, F; Santori, N; Panegrossi, G

    1998-09-01

    We reviewed a series of 120 uncemented total hip replacements using the Omniflex stem with hydroxyapatite coating. Twenty minor intraoperative proximal fractures occurred. All fractures were treated with cerclage wiring after removal of the stem. Radiographic and clinical results of these 20 patients were compared with the remaining 100 implants in which this complication did not occur. In 20% of the cases of both groups, a migration of less than 2 mm was observed. No differences were detected in Harris Hip Scores, subsidence of the stem, and radiographic behavior. We concluded that a properly stabilized proximal femoral fracture above the lesser trochanter did not influence the clinical and radiographic results at more than 3 years follow-up.

  12. Laser Surface Treatment of Hydro and Thermal Power Plant Components and Their Coatings: A Review and Recent Findings

    NASA Astrophysics Data System (ADS)

    Mann, B. S.

    2015-11-01

    High-power diode laser (HPDL) surface modification of hydro and thermal power plant components is of the utmost importance to minimize their damages occurring due to cavitation erosion, water droplet erosion, and particle erosion (CE, WDE, and PE). Special emphasis is given on the HPDL surface treatment of martensitic and precipitate-hardened stainless steels, Ti6Al4V alloy, plasma ion nitro-carburized layers, high pressure high velocity oxy-fuel and twin-wire arc sprayed coatings. WDE test results of all these materials and coatings in `untreated' and `HPDL- treated at 1550 °C' conditions, up to 8.55 million cycles, are already available. Their WDE testing was further continued up to 10.43 million cycles. The X20Cr13 and X10CrNiMoV1222, the most common martensitic stainless steels used in hydro and thermal power plants, were HPDL surface treated at higher temperature (1650 °C) and their WDE test results were also obtained up to 10.43 million cycles. It is observed that the increased HPDL surface temperature from 1550 to 1650 °C has resulted in significant improvement in their WDE resistances because of increased martensitic (ά) phase at higher temperature. After conducting long-range WDE tests, the correlation of CE, WDE, and PE resistances of these materials and protective coatings with their mechanical properties such as fracture toughness and microhardness product, ultimate resilience, modified resilience, and ultimate modified resilience has been reviewed and discussed. One of the edges of a 500 MW low pressure steam turbine moving blade (X10CrNiMoV1222 stainless steel) was HPDL surface treated at 1550 °C and its radii of curvatures and deflections were measured. These were compared with the data available earlier from a flat rectangular sample of similar composition and identical HPDL surface temperature.

  13. Development of improved corrosion- and erosion-resistance coatings for gas-turbine airfoils

    SciTech Connect

    Shen, S.

    1980-01-01

    The main objective of this program is to obtain a ceramic coating with sufficient density to prevent hot-corrosion element diffusion while accommodating the thermal induced stresses and strain encountered in the gas turbine airfoil application. A secondary objective is to include ceramic coatings for outer air seals and combustor components such as falseheads, crossover tubes, and igniters. In addition, these coatings may directly, or with minor modification, be of major interest for insulating diesel engine combustion zones. The application objective is to significantly enhance diesel and gas turbine engine durability when operating with minimally processed alternative fuels. Both steel tabs and IN-738 pins were used as substrate to be coated with Yttria-stabilized Zirconia using EB-PVD technique. Various bond layers including CoCrAlY, NiCrAlY and NiCoCrAlY were also deposited by PVD in a 100 kW coater followed by glass bead peening and vacuum heat-treatment at 1975/sup 0/F for four (4) hours. ZrO/sub 2/(Y/sub 2/O/sub 3/) top layers were deposited in a 200 kW coater with a pressure barrier system to enable oxygen gas being introduced during the coating process. Results are presented and discussed. (WHK)

  14. Edge microstability of NSTX plasmas without and with lithium-coated plasma-facing components

    NASA Astrophysics Data System (ADS)

    Canik, J. M.; Guttenfelder, W.; Maingi, R.; Osborne, T. H.; Kubota, S.; Ren, Y.; Bell, R. E.; Kugel, H. W.; LeBlanc, B. P.; Souhkanovskii, V. A.

    2013-11-01

    The pedestal structure in NSTX is strongly affected by lithium coatings applied to the PFCs. In discharges with lithium, the density pedestal widens, and the electron temperature (Te) gradient increases inside a radius of ψN ∼ 0.95, but is unchanged for ψN > 0.95. The inferred effective electron thermal (\\chi_{e}^{eff} ) and particle (D_{e}^{eff} ) profiles reflect the profile changes: \\chi_{e}^{eff} is slightly increased in the near-separatrix region, and is reduced in the region ψN < 0.95 in the with-lithium case. The D_{e}^{eff} profile shows a broadening of the region with low diffusivity with lithium, while the minimum value within the steep-gradient region is comparable in the two cases. The linear microstability properties of the edge plasma without and with lithium have been analysed. At the pedestal top microtearing modes are unstable without lithium. These are stabilized by the stronger density gradient with lithium, becoming TEM-like with growth rates reduced and comparable to E × B shearing rates. In the region ψN > 0.95, both the pre- and with-lithium cases are calculated to be unstable to ETG modes, with higher growth rates with lithium. Both cases are also found to lie near the onset for kinetic ballooning modes, but in the second-stable region where growth rates decrease with increasing pressure gradient.

  15. Seed Coat Microsculpturing Is Related to Genomic Components in Wild Brassica juncea and Sinapis arvensis

    PubMed Central

    Kang, Ding-ming; Ma, Ke-ping

    2013-01-01

    It has been reported that wild Brassica and related species are widely distributed across Xinjiang, China, and there has been an argument for species identification. Seed coat microsculpturing (SCM) is known to be an excellent character for taxonomic and evolutionary studies. By identifying collections from Xinjiang, China, and combining SCM pattern, flow cytometry, and genome-specific DNA markers as well as sexual compatibility with known species, this study aimed to detect potential relationships between SCM and genomic types in wild Brassica and related species. Three wild collections were found to be tetraploid with a SCM reticulate pattern similar to B. juncea, and containing A and B genome-specific loci, indicating relatively high sexual compatibility with B. juncea. The others were diploid, carrying S-genome-specific DNA markers, and having relatively high sexual compatibility with Sinapis arvensis. Moreover, their SCM was in a rugose pattern similar to that of S. arvensis. It was suggested that SCM, as a morphological characteristic, can reflect genomic type, and be used to distinguish B-genome species such as B. juncea from the related S. arvensis. The relationship between SCM and genomic type can support taxonomic studies of the wild Brassica species and related species. PMID:24386242

  16. Biosynthesis, targeting and processing of oleosin-like proteins, which are major pollen coat components in Brassica napus.

    PubMed

    Murphy, D J; Ross, J H

    1998-01-01

    The purpose of this study is to characterise the biosynthesis, targeting and processing of some of the major protein components of the pollen coat, or tryphine, of Brassica napus. The authors have N-terminally sequenced 11 of the most abundant pollen coat polypeptides, and nine of these sequences correspond to proteolytically cleaved products of seven oleosin-like genes, i.e. Oln B;1 to Oln B;6 and Oln B;11. The Oln B;11 gene product is co- or post-translationally targeted in vitro to canine microsomal membranes. This implies that the oleosin-like protein is targeted to the endoplasmic reticulum in tapetal cells in vivo. Affinity-purified antibodies raised against a 20-residue domain of Oln B;3 and B;4 gene products cross-reacted with full-length proteins of 45-48 kDa in early developing (< 2 mm to 5 mm) buds and anthers, but recognised truncated proteins of 32-38 kDa at later (4 mm to 7 mm) stages of development. The 45-48 kDa immunoreactive proteins were associated with a floating lipid body fraction obtained from a tapetal/locular fluid extract from maturing anthers and a major 48 kDa polypeptide from this fraction was confirmed by N-terminal sequencing to be a full length product of the Oln B;3 gene. Quantitative immunocytochemical studies showed that the full length 45-48 kDa oleosin-like proteins were specifically localised in the interior of tapetal cytoplasmic lipid bodies where they were associated with a regular hexagonal-like fibrous reticulum. No significant labelling of elaioplasts was observed. The same antibodies specifically labelled 32-38 kDa oleosin-like proteins on the extracellular pollen coat of maturing pollen grains. These results demonstrate for the first time that many of the major pollen coat proteins are derived from an endoproteolytic cleavage of precursor oleosin-like proteins that originally accumulate within the large cytoplasmic lipid bodies of tapetal cells.

  17. Refurbishment of SRB aluminum components by walnut hull blast removal of protective coatings

    NASA Technical Reports Server (NTRS)

    Colberg, W. R.; Gordon, G. H.; Jackson, C. H.

    1982-01-01

    A test program was conducted to develop, optimize, and scale up an abrasive blasting procedure was developed for refurbishment of specific SRB components: aft skirt, forward skirt, frustrum, and painted piece parts. Test specimens utilizing 2219 T87 aluminum substrate of varying thicknesses were prepared and blasted at progressively increasing pressures with selected abrasives. Specimens were analyzed for material response. The optimum blasting parameters were determined on panel specimens and verified on a large cylindrical integrated test bed.

  18. Optical Coating Performance for Heat Reflectors of the JWST-ISIM Electronic Component

    NASA Technical Reports Server (NTRS)

    Rashford, Robert A.; Perrygo, Charles M.; Garrison, Matthew B.; White, Bryant K.; Threat, Felix T.; Quijada, Manuel A.; Jeans, James W.; Huber, Frank K.; Bousquet, Robert R.; Shaw, Dave

    2011-01-01

    A document discusses a thermal radiator design consisting of lightweight composite materials and low-emittance metal coatings for use on the James Webb Space Telescope (JWST) structure. The structure will have a Thermal Subsystem unit to provide passive cooling to the Integrated Science Instrument Module (ISIM) control electronics. The ISIM, in the JWST observatory, is the platform that provides the mounting surfaces for the instrument control electronics. Dissipating the control electronic generated-heat away from JWST is of paramount importance so that the spacecraft s own heat does not interfere with the infrared-light gathering of distant cosmic sources. The need to have lateral control in the emission direction of the IEC (ISIM Electronics Compartment) radiators led to the development of a directional baffle design that uses multiple curved mirrorlike surfaces. This concept started out from the so-called Winston non-imaging optical concentrators that use opposing parabolic reflector surfaces, where each parabola has its focus at the opposite edge of the exit aperture. For this reason they are often known as compound parabolic concentrators or CPCs. This radiator system with the circular section was chosen for the IEC reflectors because it offers two advantages over other designs. The first is that the area of the reflector strips for a given radiator area is less, which results in a lower mass baffle assembly. Secondly, the fraction of energy emitted by the radiator strips and subsequently reflected by the baffle is less. These fewer reflections reduced the amount of energy that is absorbed and eventually re-emitted, typically in a direction outside the design emission range angle. A baffle frame holds the mirrors in position above a radiator panel on the IEC. Together, these will direct the majority of the heat from the IEC above the sunshield away towards empty space.

  19. Thermochemistry of Calcium-Magnesium-Aluminum-Silicate (CMAS) and Components of Advanced Thermal and Environmental Barrier Coating Systems

    NASA Technical Reports Server (NTRS)

    Costa, Gustavo C. C.; Acosta, Waldo A.; Zhu, Dongming; Ghoshal, Anindya

    2017-01-01

    There is increasing interest in the degradation mechanism studies of thermal and environmental barrier coatings (TEBCs) of gas turbines by molten CaO-MgO-Al(exp. 2)O(exp. 3)-SiO(exp. 2) CMAS). CMAS minerals are usually referred as silicon-containing sand dust and volcano ash materials that are carried by the intake air into gas turbines, e.g. in aircraft engines, and their deposits often react at high temperatures (greater than 1200 degrees C) with the engine turbine coating systems and components. The high temperature reactions causes degradation and accelerated failure of the static and rotating components of the turbine engines. We discuss some results of the reactions between the CMAS and Rare-Earth (RE = Y, Yb, Dy, Gd, Nd and Sm) - oxide stabilized ZrO(exp. 2) or HfO(exp. 2) systems, and the stability of the resulting oxides and silicates. Plasma sprayed hollow tube samples (outside diameter = 4.7 mm, wall thickness = 0.76 mm and = 26 mm height) were half filled with CMAS powder, wrapped and sealed with platinum foil, and heat treated at 1310 degrees C for 5h. Samples were characterized by differential scanning calorimetry (DSC), X-ray diffraction, and cross-section electron microscopy analysis and energy dispersive X-ray spectroscopy. It was found that CMAS penetrated the samples at the grain boundaries and dissolved the TEBC materials to form silicate phases containing the rare-earth elements. Furthermore, it was found that apatite crystalline phases were formed in the samples with total rare-earth content higher than 12 mol% in the reaction zone for the ZrO(exp. 2) system. In general, samples with the nominal compositions (30YSZ), HfO(exp. 2)-7Dy(exp. 2)O(exp. 2) and ZrO(exp. 2)-9.5Y(exp. 2)O(exp. 3)-2.25Gd(exp. 2)O(exp. 3)-2.25Yb(exp. 2)O(exp. 3) exhibited lower reactivity or more resistance to CMAS than the other coating compositions of this work.

  20. Defect Clustering and Nano-Phase Structure Characterization of Multi-Component Rare Earth Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Chen, Yuan L.; Miller, Robert A.

    2003-01-01

    Advanced oxide thermal barrier coatings have been developed by incorporating multi-component rare earth oxide dopants into zirconia-yttria to effectively promote the creation of the thermodynamically stable, immobile oxide defect clusters and/or nano-scale phases within the coating systems. The presence of these nano-sized defect clusters has found to significantly reduce the coating intrinsic thermal conductivity, improve sintering resistance, and maintain long-term high temperature stability. In this paper, the defect clusters and nano-structured phases, which were created by the addition of multi-component rare earth dopants to the plasma-sprayed and electron-beam physical vapor deposited thermal barrier coatings, were characterized by high-resolution transmission electron microscopy (TEM). The defect cluster size, distribution, crystallographic and compositional information were investigated using high-resolution TEM lattice imaging, selected area diffraction (SAD), electron energy-loss spectroscopy (EELS) and energy dispersive spectroscopy (EDS) analysis techniques. The results showed that substantial defect clusters were formed in the advanced multi-component rare earth oxide doped zirconia- yttria systems. The size of the oxide defect clusters and the cluster dopant segregation was typically ranging from 5 to 50 nm. These multi-component dopant induced defect clusters are an important factor for the coating long-term high temperature stability and excellent performance.

  1. Defect Clustering and Nano-Phase Structure Characterization of Multi-Component Rare Earth Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Chen, Yuan L.; Miller, Robert A.

    2003-01-01

    Advanced oxide thermal barrier coatings have been developed by incorporating multi-component rare earth oxide dopants into zirconia-yttria to effectively promote the creation of the thermodynamically stable, immobile oxide defect clusters and/or nano-scale phases within the coating systems. The presence of these nano-sized defect clusters has found to significantly reduce the coating intrinsic thermal conductivity, improve sintering resistance, and maintain long-term high temperature stability. In this paper, the defect clusters and nano-structured phases, which were created by the addition of multi-component rare earth dopants to the plasma-sprayed and electron-beam physical vapor deposited thermal barrier coatings, were characterized by high-resolution transmission electron microscopy (TEM). The defect cluster size, distribution, crystallographic and compositional information were investigated using high-resolution TEM lattice imaging, selected area diffraction (SAD), electron energy-loss spectroscopy (EELS) and energy dispersive spectroscopy (EDS) analysis techniques. The results showed that substantial defect clusters were formed in the advanced multi-component rare earth oxide doped zirconia- yttria systems. The size of the oxide defect clusters and the cluster dopant segregation was typically ranging from 5 to 50 nm. These multi-component dopant induced defect clusters are an important factor for the coating long-term high temperature stability and excellent performance.

  2. Defect Clustering and Nano-Phase Structure Characterization of Multi-Component Rare Earth Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Chen, Yuan L.; Miller, Robert A.

    1990-01-01

    Advanced oxide thermal barrier coatings have been developed by incorporating multi- component rare earth oxide dopants into zirconia-yttria to effectively promote the creation of the thermodynamically stable, immobile oxide defect clusters and/or nano-scale phases within the coating systems. The presence of these nano-sized defect clusters has found to significantly reduce the coating intrinsic thermal conductivity, improve sintering resistance, and maintain long-term high temperature stability. In this paper, the defect clusters and nano-structured phases, which were created by the addition of multi-component rare earth dopants to the plasma- sprayed and electron-beam physical vapor deposited thermal barrier coatings, were characterized by high-resolution transmission electron microscopy (TEM). The defect cluster size, distribution, crystallographic and compositional information were investigated using high-resolution TEM lattice imaging, selected area diffraction (SAD), and energy dispersive spectroscopy (EDS) analysis techniques. The results showed that substantial defect clusters were formed in the advanced multi-component rare earth oxide doped zirconia-yttria systems. The size of the oxide defect clusters and the cluster dopant segregation was typically ranging fiom 5 to 50 nm. These multi-component dopant induced defect clusters are an important factor for the coating long-term high temperature stability and excellent performance.

  3. Secretory COPII coat component Sec23a is essential for craniofacial chondrocyte maturation.

    PubMed

    Lang, Michael R; Lapierre, Lynne A; Frotscher, Michael; Goldenring, James R; Knapik, Ela W

    2006-10-01

    An increasing number of human disorders have been linked to mutations in genes of the secretory pathway. The chemically induced zebrafish crusher variant results in malformed craniofacial skeleton, kinked pectoral fins and a short body length. By positional cloning, we identified a nonsense mutation converting leucine to a stop codon (L402X) in the sec23a gene, an integral component of the COPII complex, which is critical for anterograde protein trafficking between endoplasmic reticulum and Golgi apparatus. Zebrafish crusher mutants develop normally until the onset of craniofacial chondrogenesis. crusher chondrocytes accumulate proteins in a distended endoplasmic reticulum, resulting in severe reduction of cartilage extracellular matrix (ECM) deposits, including type II collagen. We demonstrate that the paralogous gene sec23b is also an essential component of the ECM secretory pathway in chondrocytes. In contrast, knockdown of the COPI complex does not hinder craniofacial morphogenesis. As SEC23A lesions cause the cranio-lenticulo-sutural dysplasia syndrome, crusher provides the first vertebrate model system that links the biology of endoplasmic reticulum to Golgi trafficking with a clinically relevant dysmorphology.

  4. Investigation of the oxide adhesion and growth characteristics on platinum-modified aluminide coatings. Master's thesis

    SciTech Connect

    Farrell, M.S.

    1986-09-01

    The operating environment for superalloy blades and vanes in gas turbine engines has necessitated the developed of alloy coatings to achieve satisfactory resistance of the metal to oxidation and hot corrosion. Aluminide coatings were initially developed to meet this need. Recently it was shown that platinum additions significantly improve the oxidation resistance of these aluminide coatings. The effects of pre-aluminizing surface smoothness and coating structure for both platinum modified and unmodified aluminide coatings on IN-738 in a cyclic oxidation environment at 1100 C were examined. Weight change measurements were used to determine the coating oxide scale adherence characteristics and to quantify the cyclic oxidation behavior of the various coating structures.

  5. Preliminary study on nano- and micro-composite sol-gel based alumina coatings on structural components of lead-bismuth eutectic cooled fast breeder reactors

    NASA Astrophysics Data System (ADS)

    Dou, Peng; Kasada, Ryuta

    2011-02-01

    In order to protect the structural components of lead-bismuth eutectic cooled fast breeder reactors from liquid metal corrosion, Al 2O 3 nano- and micro-composite coatings were developed using an improved sol-gel process, which includes dipping specimens in a sol-gel solution dispersed with fine α-Al 2O 3 powders prepared by mechanical milling. Accelerated corrosion tests were conducted on coated specimens in liquid lead-bismuth eutectic at 500 °C under dynamic conditions. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses revealed that the coatings are composed of α-Al 2O 3 and they are about 10 μm thick. After the corrosion tests, no spallation occurred on the coatings, and neither Pb nor Bi penetrated into the coatings, which indicates that the coatings possess an enhanced dynamic LBE corrosion resistance to lead-bismuth eutectic corrosion. The nano-structured composite particles integrated into the coatings play an important role in achieving such superior lead-bismuth eutectic corrosion resistance.

  6. Prospective five-year subsidence analysis of a cementless fully hydroxyapatite-coated femoral hip arthroplasty component.

    PubMed

    Clauss, Martin; Van Der Straeten, Catherine; Goossens, Marc

    2014-01-01

    Early subsidence >1.5 mm is considered to be a predictive factor for later aseptic loosening of the femoral component following total hip arthroplasty (THA). The aim of this study was to assess five-year subsidence rates of the cementless hydroxyapatite-coated twinSys stem (Mathys Ltd., Bettlach, Switzerland).This prospective single-surgeon series examined consecutive patients receiving a twinSys stem at Maria Middelares Hospital, Belgium. Patients aged >85 years or unable to come to follow-up were excluded. Subsidence was assessed using Ein Bild Roentgen Analyse--Femoral Component Analysis (EBRA-FCA). Additional clinical and radiographic assessments were performed. Follow-ups were prospectively scheduled at two, five, 12, 24, and 60 months.In total, 218 THA (211 patients) were included. At five years, mean subsidence was 0.66 mm (95% CI: 0.43-0.90). Of the 211 patients, 95.2% had an excellent or good Harris Hip Score. There were few radiological changes. Kaplan-Meier analysis indicated five-year stem survival to be 98.4% (95% CI: 97.6-100%).Subsidence levels of the twinSys femoral stem throughout the five years of follow-up were substantially lower than the 1.5 mm level predictive of aseptic loosening. This was reflected in the high five-year survival rate.

  7. Dependence of optical properties of composite materials with nanosize oxide coatings on the properties of film-forming sols: II. Effect of the sol component concentration

    NASA Astrophysics Data System (ADS)

    Shemanin, V. G.; Atkarskaya, A. B.

    2015-07-01

    We consider the effect of the component structure of a sol on optical characteristics (microscopic structure, refractive index and thickness of coating, reflectance, transmittance, and optical loss in composites of the type of a glass substrate + a nanosize oxide coating of the CuO-TiO2 system) of composite materials with nanosize coatings, which are obtained in accordance with the sol-gel technology. It is shown that the chemical composition of precursors considerably affects the maturing of alcosols, the structure of coatings, and optical characteristics of composites. It is proposed that the dispersed phase represented by nanotubes facilitates a closer packing of particles into a layer as compared to the pseudospherical phase.

  8. Potential of direct metal deposition technology for manufacturing thick functionally graded coatings and parts for reactors components

    NASA Astrophysics Data System (ADS)

    Thivillon, L.; Bertrand, Ph.; Laget, B.; Smurov, I.

    2009-03-01

    Direct metal deposition (DMD) is an automated 3D deposition process arising from laser cladding technology with co-axial powder injection to refine or refurbish parts. Recently DMD has been extended to manufacture large-size near-net-shape components. When applied for manufacturing new parts (or their refinement), DMD can provide tailored thermal properties, high corrosion resistance, tailored tribology, multifunctional performance and cost savings due to smart material combinations. In repair (refurbishment) operations, DMD can be applied for parts with a wide variety of geometries and sizes. In contrast to the current tool repair techniques such as tungsten inert gas (TIG), metal inert gas (MIG) and plasma welding, laser cladding technology by DMD offers a well-controlled heat-treated zone due to the high energy density of the laser beam. In addition, this technology may be used for preventative maintenance and design changes/up-grading. One of the advantages of DMD is the possibility to build functionally graded coatings (from 1 mm thickness and higher) and 3D multi-material objects (for example, 100 mm-sized monolithic rectangular) in a single-step manufacturing cycle by using up to 4-channel powder feeder. Approved materials are: Fe (including stainless steel), Ni and Co alloys, (Cu,Ni 10%), WC compounds, TiC compounds. The developed coatings/parts are characterized by low porosity (<1%), fine microstructure, and their microhardness is close to the benchmark value of wrought alloys after thermal treatment (Co-based alloy Stellite, Inox 316L, stainless steel 17-4PH). The intended applications concern cooling elements with complex geometry, friction joints under high temperature and load, light-weight mechanical support structures, hermetic joints, tubes with complex geometry, and tailored inside and outside surface properties, etc.

  9. Effect of Blood Component Coatings of Enosseal Implants on Proliferation and Synthetic Activity of Human Osteoblasts and Cytokine Production of Peripheral Blood Mononuclear Cells

    PubMed Central

    Hulejova, Hana; Bartova, Jirina; Riedel, Tomas; Pesakova, Vlasta

    2016-01-01

    The study monitored in vitro early response of connective tissue cells and immunocompetent cells to enosseal implant materials coated by different blood components (serum, activated plasma, and plasma/platelets) to evaluate human osteoblast proliferation and synthetic activity and inflammatory response presented as a cytokine profile of peripheral blood mononuclear cells (PBMCs) under conditions imitating the situation upon implantation. The cells were cultivated on coated Ti-plasma-sprayed (Ti-PS), Ti-etched (Ti-Etch), Ti-hydroxyapatite (Ti-HA), and ZrO2 surfaces. The plasma/platelets coating supported osteoblast proliferation only on osteoconductive Ti-HA and Ti-Etch whereas activated plasma enhanced proliferation on all surfaces. Differentiation (BAP) and IL-8 production remained unchanged or decreased irrespective of the coating and surface; only the serum and plasma/platelets-coated ZrO2 exhibited higher BAP and IL-8 expression. RANKL production increased on serum and activated plasma coatings. PBMCs produced especially cytokines playing role in inflammatory phase of wound healing, that is, IL-6, GRO-α, GRO, ENA-78, IL-8, GM-CSF, EGF, and MCP-1. Cytokine profiles were comparable for all tested surfaces; only ENA-78, IL-8, GM-CSF, and MCP-1 expression depended on materials and coatings. The activated plasma coating led to uniformed surfaces and represented a favorable treatment especially for bioinert Ti-PS and ZrO2 whereas all coatings had no distinctive effect on bioactive Ti-HA and Ti-Etch. PMID:27651560

  10. In vivo testing of canine prosthetic femoral components with HA-Ti ladder-type coating on vacuum plasma-sprayed Ti substrate.

    PubMed

    Zeng, Xian-lin; Li, Jing-feng; Yang, Shu-hua; Zheng, Qi-xin; Zou, Zhen-wei

    2013-08-01

    The purpose of the present study was to observe the structure and functional change of the bone-coating-prosthesis interface in vivo and to evaluate the histocompatibility of self-made prosthetic femoral components in the body and the degree of their bonding with the surrounding bone tissues as well as their stability. Six mature beagle dogs underwent bilateral hip replacement with prosthetic femur components. Three groups were established in terms of different coating of prothesis (four joints in each group): atmosphere (A) plasma-sprayed pure titanium (Ti) prosthetic joint with hydroxyapatite (HA) coating (HA+Ti+A group); vacuum (V) plasma-sprayed pure Ti prosthetic joint with HA coating (HA+Ti+V group); vacuum plasma-sprayed pure Ti prosthetic joint with Ti-HA stepped coating (Ti+HAG+Ti+V group). The hip joints were functionally evaluated, and subjected to X-ray examination, biomechanics inspection, and histological examination. As a result, X-ray imaging revealed all prosthetic joints were in a good location and no dislocation of joint was found. Shear strength of interface was significantly higher in Ti+HAG+Ti+V group than in HA+Ti+V group (P<0.05) and HA+Ti+A group (P<0.05) at 28th week. Histological examination showed the amount of newborn bone in Ti+HAG+Ti+V group was more than in HA+Ti+V group and HA+Ti+A group after 28 weeks. It was suggested that vacuum plasma-sprayed pure Ti prosthetic joint with TI-HA stepped coating could improve the bonding capacity of bone-prosthesis, enhance the stability of prosthesis, and increase the fixion of prosthetic femoral components because of better bone growth. This new type of biological material in prosthetic femoral components holds promises for application in clinical practice.

  11. Preparation and properties of high storage stability polyester polyol dispersion for two-component waterborne polyurethane coating

    NASA Astrophysics Data System (ADS)

    Hao, H.; Hu, J. Q.; Wang, F.; Tu, W. P.

    2017-01-01

    A new type of polyester polyol dispersion with good storage stability was prepared based on a hydrophilic monomer 5-sodium sulfodimethyl isophthalate (5-SIPM), and frequently-used monomers such as neopentyl glycol (NPG), dimethyl terephthalate (DMT), dimethyl phthalate (DMP) and trimethylolpropane (TMP) by the transpolycondensation and polycondensation method. The polyester polyol dispersion was characterized by FTIR and GPC. The proper content of these monomers were determined by the performance of polyester dispersion: the content of TMP was 15wt%, the content of NPG was 7.5wt% and the hydrophilic monomer 5-SIPM content was 5wt%. Two-component waterborne polyurethane (2K-WPU) coatings were prepared by Bayhydur® XP2487/1 and polyester polyol dispersions, which were stored before and after at 40 ° for 6 weeks, the prepared films have no differences in drying time, adhesion, pencil hardness, gloss and chemical resistance, the result also reveals that the polyester polyol dispersion have excellent storage stability resistance.

  12. Lithium coatings on NSTX plasma facing components and its effects on boundary control, core plasma performance, and operation

    SciTech Connect

    Kugel, H. W.; Bell, M. G.; Maingi, R.

    2010-01-01

    NSTX high power divertor plasma experiments have used in succession lithium pellet injection (LPI), evaporated lithium, and injected lithium powder to apply lithium coatings to graphite plasma facing components. In 2005, following the wall conditioning and LPI, discharges exhibited edge density reduction and performance improvements. Since 2006, first one, and now two lithium evaporators have been used routinely to evaporate lithium onto the lower divertor region at total rates of 10-70 mg/min for periods 5-10 min between discharges. Prior to each discharge, the evaporators are withdrawn behind shutters. Significant improvements in the performance of NBI heated divertor discharges resulting from these lithium depositions were observed. These evaporators are now used for more than 80% of NSTX discharges. Initial work with injecting fine lithium powder into the edge of NBI heated deuterium discharges yielded comparable changes in performance. Several operational issues encountered with lithium wall conditions, and the special procedures needed for vessel entry are discussed. The next step in this work is installation of a liquid lithium divertor surface on the outer part of the lower divertor.

  13. Lithium Coatings on NSTX Plasma Facing Components and Its Effects On Boundary Control, Core Plasma Performance, and Operation

    SciTech Connect

    H.W.Kugel, M.G.Bell, H.Schneider, J.P.Allain, R.E.Bell, R Kaita, J.Kallman, S. Kaye, B.P. LeBlanc, D. Mansfield, R.E. Nygen, R. Maingi, J. Menard, D. Mueller, M. Ono, S. Paul, S.Gerhardt, R.Raman, S.Sabbagh, C.H.Skinner, V.Soukhanovskii, J.Timberlake, L.E.Zakharov, and the NSTX Research Team

    2010-01-25

    NSTX high-power divertor plasma experiments have used in succession lithium pellet injection (LPI), evaporated lithium, and injected lithium powder to apply lithium coatings to graphite plasma facing components. In 2005, following wall conditioning and LPI, discharges exhibited edge density reduction and performance improvements. Since 2006, first one, and now two lithium evaporators have been used routinely to evaporate lithium onto the lower divertor region at total rates of 10-70 mg/min for periods 5-10 min between discharges. Prior to each discharge, the evaporators are withdrawn behind shutters. Significant improvements in the performance of NBI heated divertor discharges resulting from these lithium depositions were observed. These evaporators are now used for more than 80% of NSTX discharges. Initial work with injecting fine lithium powder into the edge of NBI heated deuterium discharges yielded comparable changes in performance. Several operational issues encountered with lithium wall conditions, and the special procedures needed for vessel entry are discussed. The next step in this work is installation of a Liquid Lithium Divertor surface on the outer part of the lower divertor.

  14. Metal Coatings

    NASA Technical Reports Server (NTRS)

    1994-01-01

    During the Apollo Program, General Magnaplate Corporation developed process techniques for bonding dry lubricant coatings to space metals. The coatings were not susceptible to outgassing and offered enhanced surface hardness and superior resistance to corrosion and wear. This development was necessary because conventional lubrication processes were inadequate for lightweight materials used in Apollo components. General Magnaplate built on the original technology and became a leader in development of high performance metallurgical surface enhancement coatings - "synergistic" coatings, - which are used in applications from pizza making to laser manufacture. Each of the coatings is designed to protect a specific metal or group of metals to solve problems encountered under operating conditions.

  15. Development of wear-resistant ceramic coatings for diesel engine components. Volume 1, Coating development and tribological testing: Final report: DOE/ORNL Ceramic Technology Project

    SciTech Connect

    Naylor, M.G.S.

    1992-06-01

    The tribological properties of a variety of advanced coating materials have been evaluated under conditions which simulate the piston ring -- cylinder liner environment near top ring reversal in a heavy duty diesel engine. Coated ``ring`` samples were tested against a conventional pearlitic grey cast iron liner material using a high temperature reciprocating wear test rig. Tests were run with a fresh CE/SF 15W40lubricant at 200 and 350{degrees}C, with a high-soot, engine-tested oil at 200{degrees}C and with no lubrication at 200{degrees}C. For lowest wear under boundary lubricated conditions, the most promising candidates to emerge from this study were high velocity oxy-fuel (HVOF) Cr{sub 3} C{sub 2} - 20% NiCr and WC - 12% Co cermets, low temperature arc vapor deposited (LTAVD) CrN and plasma sprayed chromium oxides. Also,plasma sprayed Cr{sub 2}O{sub 3} and A1{sub 2}O{sub 3}-ZrO{sub 2} materials were found to give excellent wear resistance in unlubricated tests and at extremely high temperatures (450{degrees}C) with a syntheticoil. All of these materials would offer substantial wear reductions compared to the conventional electroplated hard chromium ring facing and thermally sprayed metallic coatings, especially at high temperatures and with high-soot oils subjected to degradation in diesel environments. The LTAVD CrN coating provided the lowest lubricated wear rates of all the materials evaluated, but may be too thin (4 {mu}m) for use as a top ring facing. Most of the coatings evaluated showed higher wear rates with high-soot, engine-tested oil than with fresh oil, with increases of more than a factor of ten in some cases. Generally, metallic materials were found to be much more sensitive to soot/oil degradation than ceramic and cermet coatings. Thus, decreased ``soot sensitivity`` is a significant driving force for utilizing ceramic or cermet coatings in diesel engine wear applications.

  16. Protection efficacy of gloves against components of the solvent in a sprayed isocyanate coating utilizing a reciprocating permeation panel.

    PubMed

    Ceballos, Diana M; Reeb-Whitaker, Carolyn; Sasakura, Miyoko; Dills, Russell; Yost, Michael G

    2015-04-01

    Determine protection effectiveness of 5-mil natural rubber latex (0.13-mm), 5-mil nitrile rubber (0.13-mm), and 13-mil butyl rubber (0.33-mm) glove materials against solvents present in a commonly used automotive clear coat formulation using a novel permeation panel. The latex and nitrile gloves were the type commonly used by local autobody spray painters. Glove materials were tested by spraying an automotive clear coat onto an automated reciprocating permeation panel (permeation panel II). Temperature, relative humidity, and spray conditions were controlled to optimize clear coat loading homogeneity as evaluated by gravimetric analysis. Solvent permeation was measured using charcoal cloth analyzed by the National Institute for Occupational Safety and Health 1501 method. Natural rubber latex allowed 3-5 times the permeation of solvents relative to nitrile rubber for all 10 solvents evaluated: ethyl benzene, 2-heptanone, 1-methoxy-2-propyl acetate, o-xylene, m-xylene, p-xylene, n-butyl acetate, methyl isobutyl ketone, petroleum distillates, and toluene. There is a distinct behavior in solvent permeation before and after the coating dry time. Solvent permeation increased steadily before coating dry time and remained fairly constant after coating dry time. Butyl was not permeated by any of the solvents under the conditions tested. Commonly used 5-mil thick (0.13-mm) latex and nitrile gloves were ineffective barriers to solvents found in a commonly used clear coat formulation. Conversely, 13-mil (0.33-mm) butyl gloves were found to be protective against all solvents in the clear coat formulation. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  17. Four carcinoembryonic antigen subfamily members, CEA, NCA, BGP and CGM2, selectively expressed in the normal human colonic epithelium, are integral components of the fuzzy coat.

    PubMed

    Frängsmyr, L; Baranov, V; Hammarström, S

    1999-01-01

    To elucidate which of the seven transcriptionally active genes of the carcinoembryonic antigen (CEA) subfamily are expressed in human colon, we first examined mRNA expression using reverse transcriptase PCR. The result showed the CEA, nonspecific crossreacting antigen 50/90 (NCA), biliary glycoprotein (BGP), and carcinoembryonic antigen gene family member 2 (CGM2) mRNAs were expressed in the colon. To determine the cellular sources of these members within normal colonic mucosa, in situ hybridization and immunocytochemistry were then performed. CEA and NCA mRNAs were clearly detectable in the cytoplasm of columnar and goblet cells at the free luminal surface and the upper crypts with low hybridization in the mid crypt and the crypt base. In contrast, BGP and CGM2 mRNAs were restricted only to columnar cells at the upper third of the crypts and the luminal surface. Colon epithelium expression of CEA, NCA, BGP and CGM2 coincided with that of corresponding mRNAs. Ultrastructurally, CEA, NCA, BGP and CGM2 were localized mainly to the apical surface glycocalyx, the fuzzy coat, of columnar cells. Interestingly, these molecules were localized in different microdomains within the fuzzy coat. Furthermore, BGP was highly expressed in the fuzzy coat of cryptal caveolated cells. As integral components of the fuzzy coat, CEA, NCA, BGP and CGM2 can hardly function as intercellular adhesion molecules; they possibly play an important role in epithelial-microbial interactions.

  18. Nondestructive analysis of structure and components of tablet coated with film by the usage of terahertz time-domain reflection spectroscopy.

    PubMed

    Takeuchi, Issei; Shimakura, Kemmaro; Ohtake, Hideyuki; Takayanagi, Jun; Tomoda, Keishiro; Nakajima, Takehisa; Terada, Hiroshi; Makino, Kimiko

    2014-01-01

    Nondestructive analysis of tablet is of great importance from the aspect of productivity and safety. In terahertz (THz) region, however, the analysis of core of coated tablet has not been progressed. In this study, we have measured a flat-surface push-pull osmotic pump tablet, having no orifice, having bilayer core and a coating film layer. The bilayer core was made from the drug layer and the push layer, and acetaminophen was contained in the drug layer as a model drug. To study its structure and components, we have obtained reflection spectra from the drug layer side and the push layer side measurements using THz time-domain reflection spectroscopy (THz-TDRS). From these results, detection of the peak of acetaminophen in the spectrum from the drug layer side measurements was confirmed. We have made ridges approximated toward the peak using a general method of linear regression analysis in both spectra. Two-sample t-test was applied to their gradients, and significant difference between the drug layer and the push layer was shown. These results suggested that THz-TDRS is applicable to the analysis of structure and component of a coated tablet.

  19. Effect of electrolyte components on the magnetic and magnetoresistive characteristics of Fe-containing plasma electrolytic oxide coatings on titanium

    NASA Astrophysics Data System (ADS)

    Rudnev, V. S.; Adigamova, M. V.; Tkachenko, I. A.; Sergienko, V. I.; Yanushkevich, K. I.; Aplesnin, S. S.; Lukiyanchuk, I. V.; Morozova, V. P.; Medkov, M. A.

    2017-03-01

    The effect replacing Na3PO4 with Na2HPO4 in aqueous phosphate-borate-tungstate electrolyte that additionally contains Fe2(C2O4)3 on the magnetic and magnetoresistive characteristics of oxide coating/ titanium composites formed by means of plasma electrolytic oxidation (PEO) is investigated. It is established that PEO coatings with ferromagnetic characteristics form on titanium in an electrolyte containing Na3PO4 (pH 11) upon adding iron(III) oxalate, while replacing Na3PO4 with Na2HPO4 and the respective drop in the pH of the base electrolyte down to 9.8 results in the formation of coatings with different magnetic characteristics. The correlation between changes in the values of the charge carriers' activation energy and the magnetic susceptibility is demonstrated for the latter. An increase in the electric resistance of coatings in a magnetic field is observed, and the type of the magnetic resistance temperature dependence is established.

  20. Bacterially facilitated rock-coating formation as a component of the geochemical budget in cold climates: An example from Kärkevagge, Swedish Lapland

    NASA Astrophysics Data System (ADS)

    Marnocha, Cassandra L.; Dixon, John C.

    2014-08-01

    Environmental microbiology and advances in molecular techniques have been a driving force in advancing the understanding of microbial communities in previously understudied environments. Though it is widely accepted that biological and geological processes are closely linked, the importance of microbes in geomorphological processes has been understated. Microbes interact with the environment, playing a significant role in nutrient cycling, ion mobilization, and metal scavenging and concentration. Although in some of these areas understanding is expanding, the role of microbes in geochemical budgets in cold climates has been largely ignored. To investigate one such case of microbial influence, we focus on rock-coating development in the glacially eroded valley, Kärkevagge, in arctic-alpine Sweden. This bacterial diversity study shows evidence of a link between microbe-mineral interactions and key processes in the formation of diverse geochemical rock coatings. Here, we present a study of the bacterial role in metal scavenging and coating formation as a component of the geochemical budget of the valley.

  1. Oxidation in oxygen at 900 deg and 1000 deg C of four nickel-base cast superalloys: NASA-TRW VIA, B-1900, alloy 713C, and IN-738

    NASA Technical Reports Server (NTRS)

    Fryburg, G. C.; Kohl, F. J.; Stearns, C. A.

    1977-01-01

    The oxidation at 900 and 1,000 C of four nickel-base superalloys in 1 atmosphere of slowly flowing oxygen was investigated. Thermogravimetric rate data were obtained for periods to 100 hours. The morphology and composition of the oxide scales formed after 100 hours were studied by optical microscopy, X-ray diffraction, electron microprobe, scanning electron microscopy, and X-ray photoelectron spectroscopy (ESCA). Alloys B-1900 and VIA were found to be primarily alumina formers, though probably 25 percent of their surface was covered by CR2O3-containing oxides at 900 C. Alloys 713C and IN-738 were primarily chromia formers, though the surface of 713C at 1,000 C was covered with NiO, and the surface of IN-738 at both temperatures was covered with a thin layer of TiO2.

  2. In vitro evaluation of whole faba bean and its seed coat as a potential source of functional food components.

    PubMed

    Çalışkantürk Karataş, Selen; Günay, Demet; Sayar, Sedat

    2017-09-01

    In vitro studies were conducted to evaluate the particular nutritional benefits of whole faba bean seed (WFB) and fava bean seed coat (FBSC). Total dietary fiber contents of WFB and FBSC were 27.5% and 82.3%, respectively. FBSC were contained much higher total phenolic substances, condensed tannins, and total antioxidant activity than WFB. Bile acid (BA)-binding capacities of in vitro digested samples and nutritionally important products produced by in vitro fermentation of digestion residues were also studied. The BA-binding capacities of WFB and FBSC were 1.94 and 37.50μmol/100mg, respectively. Total BA bound by FBSC was even higher than the positive standard cholestyramine. Lignin and other constituents of the Klason residue were found to influence BA-binding properties. Moreover, the extent of the in vitro fermentation process showed that, fermentability of FBSC residue was significantly lower than that of WFB residue. Overall, faba bean, especially its seed coat, has great potential as a functional food. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Sec31 encodes an essential component of the COPII coat required for transport vesicle budding from the endoplasmic reticulum.

    PubMed Central

    Salama, N R; Chuang, J S; Schekman, R W

    1997-01-01

    The COPII vesicle coat protein promotes the formation of endoplasmic reticulum- (ER) derived transport vesicles that carry secretory proteins to the Golgi complex in Saccharomyces cerevisiae. This coat protein consists of Sar1p, the Sec23p protein complex containing Sec23p and Sec24p, and the Sec13p protein complex containing Sec13p and a novel 150-kDa protein, p150. Here, we report the cloning and characterization of the p150 gene. p150 is encoded by an essential gene. Depletion of this protein in vivo blocks the exit of secretory proteins from the ER and causes an elaboration of ER membranes, indicating that p150 is encoded by a SEC gene. Additionally, overproduction of the p150 gene product compromises the growth of two ER to Golgi sec mutants: sec16-2 and sec23-1. p150 is encoded by SEC31, a gene isolated in a genetic screen for mutations that accumulate unprocessed forms of the secretory protein alpha-factor. The sec31-1 mutation was mapped by gap repair, and sequence analysis revealed an alanine to valine change at position 1239, near the carboxyl terminus. Sec31p is a phosphoprotein and treatment of the Sec31p-containing fraction with alkaline phosphatase results in a 50-75% inhibition of transport vesicle formation activity in an ER membrane budding assay. Images PMID:9190202

  4. Effects of MAR-M247 substrate (modified) composition on coating oxidation coating/substrate interdiffusion. M.S. Thesis. Final Report; [protective coatings for hot section components of gas turbine engines

    NASA Technical Reports Server (NTRS)

    Pilsner, B. H.

    1985-01-01

    The effects of gamma+gamma' Mar-M247 substrate composition on gamma+beta Ni-Cr-Al-Zr coating oxidation and coating/substrate interdiffusion were evaluated. These results were also compared to a prior study for a Ni-Cr-Al-Zr coated gamma Ni-Cr-Al substrate with equivalent Al and Cr atomic percentages. Cyclic oxidation behavior at 1130 C was investigated using change in weight curves. Concentration/distance profiles were measured for Al, Cr, Co, W, and Ta. The surface oxides were examined by X-ray diffraction and scanning electron microscopy. The results indicate that variations of Ta and C concentrations in the substrate do not affect oxidation resistance, while additions of grain boundary strengthening elements (Zr, Hf, B) increase oxidation resistance. In addition, the results indicate that oxidation phenomena in gamma+beta/gamma+gamma' Mar-M247 systems have similar characteristics to the l gamma+beta/gamma Ni-Cr-Al system.

  5. Evaluation of a universal point-of-issue assay for bacterial detection in buffy coat platelet components.

    PubMed

    Ramirez-Arcos, S; Kou, Y; Perkins, H

    2014-08-01

    Bacterial contamination of platelet concentrates poses a major post-transfusion infectious risk. This study was aimed at evaluating the efficacy of the BacTx(®) assay (Immunetics Inc.) for bacterial detection in leucocyte-reduced buffy coat platelet pools and for its sensitivity in detecting clinical isolates, including bacteria that form surface-attached aggregates (biofilm positives). Platelet pools were inoculated at bacterial concentrations of 0·8-13 CFU/ml. The BacTx(®) assay detected all species at concentrations ≥10(3)  CFU/ml within 20-69 h of platelet incubation. Detection of slow-growing and biofilm-forming strains was delayed in comparison with the other strains. This assay could be used as a point-of-issue method to increase the safety of the platelet supply. © 2014 International Society of Blood Transfusion.

  6. Effects of the Acrylic Polyol Structure and the Selectivity of the Employed Catalyst on the Performance of Two-Component Aqueous Polyurethane Coatings

    PubMed Central

    Cakic, Suzana; Lacnjevac, Caslav; Stamenkovic, Jakov; Ristic, Nikola; Takic, Ljiljana; Barac, Miroljub; Gligoric, Miladin

    2007-01-01

    Two kinds of aqueous acrylic polyols (single step and multi step synthesis type) have been investigated for their performance in the two-component aqueous polyurethane application, by using more selective catalysts. The aliphatic polyfunctional isocyanates based on hexamethylen diisocyanates have been employed as suitable hardeners. The complex of zirconium, commercially known as K-KAT®XC-6212, and manganese (III) complexes with mixed ligands based on the derivative of maleic acid have been used as catalysts in this study. Both of the aqueous polyols give good results, in terms of application and hardness, when elevated temperatures and more selective catalysts are applied. A more selective catalyst promotes the reaction between the isocyanate and polyol component. This increases the percentage of urethane bonds and the degree of hardness in the films formed from the two components of aqueous polyurethane lacquers. The polyol based on the single step synthesis route is favourable concerning potlife and hardness. The obtained results show that the performance of the two-component aqueous polyurethane coatings depends on the polymer structure of the polyols as well as on the selectivity of the employed catalyst.

  7. A new uncemented hydroxyapatite-coated femoral component for the treatment of femoral neck fractures: two-year radiostereometric and bone densitometric evaluation in 50 hips.

    PubMed

    Sköldenberg, O G; Salemyr, M O; Bodén, H S; Lundberg, A; Ahl, T E; Adolphson, P Y

    2011-05-01

    Our aim in this pilot study was to evaluate the fixation of, the bone remodelling around, and the clinical outcome after surgery of a new, uncemented, fully hydroxyapatite-coated, collared and tapered femoral component, designed specifically for elderly patients with a fracture of the femoral neck. We enrolled 50 patients, of at least 70 years of age, with an acute displaced fracture of the femoral neck in this prospective single-series study. They received a total hip replacement using the new component and were followed up regularly for two years. Fixation was evaluated by radiostereometric analysis and bone remodelling by dual-energy x-ray absorptiometry. Hip function and the health-related quality of life were assessed using the Harris hip score and the EuroQol-5D. Up to six weeks post-operatively there was a mean subsidence of 0.2 mm (-2.1 to +0.5) and a retroversion of a mean of 1.2° (-8.2° to +1.5°). No component migrated after three months. The patients had a continuous loss of peri-prosthetic bone which amounted to a mean of 16% (-49% to +10%) at two years. The mean Harris hip score was 82 (51 to 100) after two years. The two-year results from this pilot study indicate that this new, uncemented femoral component can be used for elderly patients with osteoporotic fractures of the femoral neck.

  8. Effect of adhesive properties of buffy coat on the quality of blood components produced with Top & Top and Top & Bottom bags

    PubMed Central

    Cerelli, Eugenio; Nocera, Martina; Di Bartolomeo, Erminia; Panzani, Paola; Baricchi, Roberto

    2015-01-01

    Background The Transfusion Medicine Unit of Reggio Emilia currently collects whole blood using conventional quadruple Fresenius Top & Top bags. In this study, new Fresenius Top & Bottom bags were assessed and compared to the routine method with regards to product quality and operational requirements. Material and methods Twenty-one whole blood units were collected with both the new and the traditional bags, and then separated. Quality control data were evaluated and compared in order to estimate yield and quality of final blood components obtained with the two systems. We collected other bags, not included in the ordinary quality control programme, for comparison of platelet concentrates produced by pools of buffy coat. Results Compared to the traditional system, the whole blood units processed with Top & Bottom bags yielded larger plasma volumes (+5.7%) and a similar amount of concentrated red blood cells, but with a much lower contamination of lymphocytes (−61.5%) and platelets (−86.6%). Consequently, the pooled platelets contained less plasma (−26.3%) and were significantly richer in platelets (+17.9%). Discussion This study investigated the effect of centrifugation on the adhesiveness of the buffy coat to the bag used for whole blood collection. We analysed the mechanism by which this undesirable phenomenon affects the quality of packed red blood cells in two types of bags. We also documented the incomparability of measurements on platelet concentrates performed with different principles of cell counting: this vexing problem has important implications for biomedical research and for the establishment of universal product standards. Our results support the conclusion that the Top & Bottom bags produce components of higher quality than our usual system, while having equal operational efficiency. Use of the new bags could result in an important quality improvement in blood components manufacturing. PMID:25545866

  9. Effect of adhesive properties of buffy coat on the quality of blood components produced with Top & Top and Top & Bottom bags.

    PubMed

    Cerelli, Eugenio; Nocera, Martina; Di Bartolomeo, Erminia; Panzani, Paola; Baricchi, Roberto

    2015-04-01

    The Transfusion Medicine Unit of Reggio Emilia currently collects whole blood using conventional quadruple Fresenius Top & Top bags. In this study, new Fresenius Top & Bottom bags were assessed and compared to the routine method with regards to product quality and operational requirements. Twenty-one whole blood units were collected with both the new and the traditional bags, and then separated. Quality control data were evaluated and compared in order to estimate yield and quality of final blood components obtained with the two systems. We collected other bags, not included in the ordinary quality control programme, for comparison of platelet concentrates produced by pools of buffy coat. Compared to the traditional system, the whole blood units processed with Top & Bottom bags yielded larger plasma volumes (+5.7%) and a similar amount of concentrated red blood cells, but with a much lower contamination of lymphocytes (-61.5%) and platelets (-86.6%). Consequently, the pooled platelets contained less plasma (-26.3%) and were significantly richer in platelets (+17.9%). This study investigated the effect of centrifugation on the adhesiveness of the buffy coat to the bag used for whole blood collection. We analysed the mechanism by which this undesirable phenomenon affects the quality of packed red blood cells in two types of bags. We also documented the incomparability of measurements on platelet concentrates performed with different principles of cell counting: this vexing problem has important implications for biomedical research and for the establishment of universal product standards. Our results support the conclusion that the Top & Bottom bags produce components of higher quality than our usual system, while having equal operational efficiency. Use of the new bags could result in an important quality improvement in blood components manufacturing.

  10. Characterization of blood components separated from donated whole blood after an overnight holding at room temperature with the buffy coat method.

    PubMed

    Lu, Fa Qiang; Kang, Wei; Peng, Yu; Wang, Wei Ming

    2011-10-01

    With buffy coat (BC) processing of whole blood (WB) donations, increase in WB storage time to facilitate overnight holding before the separation of blood components would be a logistically attractive development. This study undertakes a comparative in vitro characterization of blood components prepared from WB samples that were either processed within 8 hours or stored overnight at room temperature before processing by the BC method. The WB units (400 mL) collected were either processed within 8 hours (fresh blood) or stored overnight (overnight blood) at room temperature. WB units were separated into individual-component red blood cells (RBCs), BC, and plasma. The in vitro quality of these blood components (RBCs, pooled platelet concentrates [PCs], and plasma) was analyzed during storage. Levels of 2,3-diphosphoglycerate (2,3-DPG) were found to be significantly lower immediately after processing, compared with the fresh WB samples, in RBCs that had been separated from an overnight-hold sample. However, this difference was not apparent after 14 days of storage. In pooled PCs, measurements for glucose, lactate, PO(2), PCO(2), extent of shape change, and hypotonic shock response were similar. The platelet yield in PCs prepared from an overnight-hold WB sample was significantly higher, while CD62P expression and annexin V binding were lower (p < 0.05). For frozen plasma (FP), no significant differences were observed for the coagulation factors (F)II, FVII, FV, F IX, FX, and FXI; fibrinogen; and von Willebrand factor content between the 8- and 24-hour FP. The FVIII was the component that was most sensitive to the prolongation of production time and it only had 80% of the activity of the 8-hour FP. These data suggest that blood components (RBCs, pooled PCs, and FP) separated from WB that has been stored overnight at room temperature by the BC method are of acceptable quality. © 2011 American Association of Blood Banks.

  11. Three-component vesicle aggregation driven by adhesion interactions between Au nanoparticles and polydopamine-coated nanotubes.

    PubMed

    Jin, Haibao; Zhou, Yongfeng; Huang, Wei; Zheng, Yongli; Zhu, Xinyuan; Yan, Deyue

    2014-06-11

    Large-scale and robust vesicle aggregates were obtained through molecular recognition among cell-sized polymer vesicles, carbon nanotubes and AuNPs, driven by adhesion interactions between Au and polydopamine. Vesicle fusion was effectively avoided in this three-component vesicle aggregation process.

  12. Two-component spin-coated Ag/CNT composite films based on a silver heterogeneous nucleation mechanism adhesion-enhanced by mechanical interlocking and chemical grafting

    NASA Astrophysics Data System (ADS)

    Zhang, Yang; Kang, Zhixin; Bessho, Takeshi

    2017-03-01

    In this paper, a new method for the synthesis of silver carbon nanotube (Ag/CNT) composite films as conductive connection units for flexible electronic devices is presented. This method is about a two-component solution process by spin coating with an after-treatment annealing process. In this method, multi-walled carbon nanotubes (MWCNTs) act as the core of silver heterogeneous nucleation, which can be observed and analyzed by a field-emission scanning electron microscope. With the effects of mechanical interlocking, chemical grafting, and annealing, the interfacial adhesive strength between films and PET sheets was enhanced to 12 N cm‑1. The tensile strength of the Ag/CNT composite films was observed to increase by 38% by adding 5 g l‑1 MWCNTs. In the four-probe method, the resistivity of Ag/CNT-5 declined by 78.2% compared with pristine Ag films. The anti-fatigue performance of the Ag/CNT composite films was monitored by cyclic bending deformation and the results revealed that the growth rate of electrical resistance during the deformation was obviously retarded. As for industrial application, this method provides an efficient low-cost way to prepare Ag/CNT composite films and can be further applied to other coating systems.

  13. Two-component spin-coated Ag/CNT composite films based on a silver heterogeneous nucleation mechanism adhesion-enhanced by mechanical interlocking and chemical grafting.

    PubMed

    Zhang, Yang; Kang, Zhixin; Bessho, Takeshi

    2017-03-10

    In this paper, a new method for the synthesis of silver carbon nanotube (Ag/CNT) composite films as conductive connection units for flexible electronic devices is presented. This method is about a two-component solution process by spin coating with an after-treatment annealing process. In this method, multi-walled carbon nanotubes (MWCNTs) act as the core of silver heterogeneous nucleation, which can be observed and analyzed by a field-emission scanning electron microscope. With the effects of mechanical interlocking, chemical grafting, and annealing, the interfacial adhesive strength between films and PET sheets was enhanced to 12 N cm(-1). The tensile strength of the Ag/CNT composite films was observed to increase by 38% by adding 5 g l(-1) MWCNTs. In the four-probe method, the resistivity of Ag/CNT-5 declined by 78.2% compared with pristine Ag films. The anti-fatigue performance of the Ag/CNT composite films was monitored by cyclic bending deformation and the results revealed that the growth rate of electrical resistance during the deformation was obviously retarded. As for industrial application, this method provides an efficient low-cost way to prepare Ag/CNT composite films and can be further applied to other coating systems.

  14. Coated article and method of making

    NASA Technical Reports Server (NTRS)

    Wang, Hongyu (Inventor); Lee, Kang Neung (Inventor)

    2002-01-01

    An article includes a silicon-containing substrate and a modified mullite coating. The modified mullite coating comprises mullite and a modifier component that reduces cracks in the modified mullite coating. The article can further comprise a thermal barrier coating applied to the modified mullite coating. The modified mullite coating functions as a bond coating between the external environmental/thermal barrier coating and the silicon-containing substrate. In a method of forming an article, a silicon-containing substrate is formed and a modified mullite coating is applied. The modified mullite coating comprises mullite and a modifier component that reduces cracks in the modified mullite coating.

  15. Coated article and method of making

    NASA Technical Reports Server (NTRS)

    Wang, Hongyu (Inventor); Lee, Kang Neung (Inventor)

    2003-01-01

    An article includes a silicon-containing substrate and a modified mullite coating. The modified mullite coating comprises mullite and a modifier component that reduces cracks in the modified mullite coating. The article can further comprise a thermal barrier coating applied to the modified mullite coating. The modified mullite coating functions as a bond coating between the external environmental/thermal barrier coating and the silicon-containing substrate. In a method of forming an article, a silicon-containing substrate is formed and a modified mullite coating is applied. The modified mullite coating comprises mullite and a modifier component that reduces cracks in the modified mullite coating.

  16. Differences in levels of platelet-derived microparticles in platelet components prepared using the platelet rich plasma, buffy coat, and apheresis procedures.

    PubMed

    Noulsri, Egarit; Udomwinijsilp, Prapaporn; Lerdwana, Surada; Chongkolwatana, Viroje; Permpikul, Parichart

    2017-04-01

    There has been an increased interest in platelet-derived microparticles (PMPs) in transfusion medicine. Little is known about PMP status during the preparation of platelet concentrates for transfusion. The aim of this study is to compare the PMP levels in platelet components prepared using the buffy coat (BC), platelet-rich plasma platelet concentrate (PRP-PC), and apheresis (AP) processes. Platelet components were prepared using the PRP-PC and BC processes. Apheresis platelets were prepared using the Trima Accel and Amicus instruments. The samples were incubated with annexin A5-FITC, CD41-PE, and CD62P-APC. At day 1 after processing, the PMPs and activated platelets were determined using flow cytometry. Both the percentage and number of PMPs were higher in platelet components prepared using the Amicus instrument (2.6±1.8, 32802±19036 particles/μL) than in platelet components prepared using the Trima Accel instrument (0.5±0.4, 7568±5298 particles/μL), BC (1.2±0.6, 12,920±6426 particles/μL), and PRP-PC (0.9±0.6, 10731±5514 particles/μL). Both the percentage and number of activated platelets were higher in platelet components prepared using the Amicus instrument (33.2±13.9, 427553±196965 cells/μL) than in platelet components prepared using the Trima Accel instrument (16.2±6.1, 211209±87706 cells/μL), BC (12.9±3.2, 140624±41003 cells/μL), and PRP-PC (21.1±6.3, 265210±86257 cells/μL). The study suggests high variability of PMPs and activated platelets in platelet components prepared using different processes. This result may be important in validating the instruments involved in platelet blood collection and processing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    1993-01-01

    In order to reduce heat transfer between a hot gas heat source and a metallic engine component, a thermal insulating layer of material is placed between them. This thermal barrier coating is applied by plasma spray processing the thin films. The coating has been successfully employed in aerospace applications for many years. Lewis Research Center, a leader in the development engine components coating technology, has assisted Caterpillar, Inc. in applying ceramic thermal barrier coatings on engines. Because these large engines use heavy fuels containing vanadium, engine valve life is sharply decreased. The barrier coating controls temperatures, extends valve life and reduces operating cost. Additional applications are currently under development.

  18. Aphid transmission of a potyvirus depends on suitability of the helper component and the N terminus of the coat protein.

    PubMed

    Dombrovsky, A; Huet, H; Chejanovsky, N; Raccah, B

    2005-02-01

    The present study investigates the specificity of potyviruses for aphid species. Two potyviruses differing in their host range were used: Zucchini yellow mosaic virus (ZYMV) mainly infecting cucurbits and Turnip mosaic virus (TuMV) mainly infecting crucifers. Two sets of aphids species were used as vectors, one polyphagous (Myzus persicae and Aphis gossypii) and the other from crucifers (Brevicoryne brassicae and Lipaphis erysimi). Evidence is provided that the specificity between a vector and a potyvirus depends either on the affinity between the aphid species and the helper component (HC) protein used or on the affinity between the HC and the virions. The difference between the two potyviruses cannot be attributed to the DAG domain which is unaltered in both N termini of the CP. Therefore, a ZYMV full length clone served to exchange a fragment encoding for the N terminus of the ZYMV CP by that of TuMV. This partial exchange in the ZYMV CP, allowed the TuMV HC to transmit the chimeric virus but not the wild type ZYMV. The significance of the N terminus context of the CP in the specificity for the HC is discussed.

  19. Susceptibility to hot corrosion of four nickel-base superalloys, NASA-TRW VIA, B-1900, 713C and IN-738

    NASA Technical Reports Server (NTRS)

    Stearns, C. A.; Kohl, F. J.; Fryburg, G. C.

    1977-01-01

    The susceptibility to hot corrosion of four nickel-base, cast superalloys has been studied at 900 and 1000 C. The test consisted of coating alloy samples with known amounts of Na2SO4 and oxidizing the coated samples isothermally in 1 atmosphere of slowly flowing oxygen, the weight-gain being monitored on a sensitive recording microbalance. Susceptibility to hot corrosion decreased in the order of decreasing molybdenum content of the alloys. Preoxidation of samples before hot-corrosion testing markedly increased the induction period observed prior to the inception of hot corrosion for all alloys tested. X-ray diffraction analyses of the oxide scales were made. All samples that underwent hot corrosion showed the presence of a (Ni,Co)MoO4 layer near the alloy-oxide interface. Several specimens displayed resistance to hot corrosion and these showed NaTaO3 as a prominent feature in their oxide scale. Our results may be interpreted as indicating that molybdenum in an alloy is detrimental, with respect to hot corrosion, while tantalum is beneficial.

  20. Effect of film thickness and viscoelasticity on separability of vapour classes by wavelet and principal component analyses of polymer-coated surface acoustic wave sensor transients

    NASA Astrophysics Data System (ADS)

    Singh, Prashant; Yadava, R. D. S.

    2011-02-01

    The transient response of a polymer-coated surface acoustic wave (SAW) vapour sensor depends on partitioning and diffusion of vapour species into the polymer in conjunction with its thickness and viscoelastic properties. The shapes of transient signals carry information about vapour identities due to specificity of the partition coefficient and the diffusion coefficient. The analysis of transient signals therefore offers a simpler approach for vapour identification in comparison to conventional electronic nose systems that employ a broadly selective sensor array. The transient response-based methods are however not developed to a similar level of maturity as their sensor array counterparts. The main reason for this is associated with complex signal generation kinetics and polymer viscoelasticity. The latter is independent of vapour identities (assuming low concentrations) but influences sensor response through nonlinear dependences on polymer thickness and viscoelastic coefficients. In this paper, we endeavour to find out whether viscoelasticity and its manifestation through thickness dependences could be turned into an advantage for transient-based vapour identification. Using an established SAW sensor model with additive noise we analyse sensor transients by wavelet decomposition and principal component analysis (PCA) for various combinations of polymer thickness, viscoelastic storage and loss moduli and noise level. We calculate vapour class separability measures defined on the basis of scatter matrices of principal components of wavelet coefficients to determine the discrimination ability of sensor transients for various combinations of film thickness and viscoelastic parameters. The simulation experiments are performed by considering a polyisobutylene-coated SAW oscillator sensor under exposure to seven volatile organic compounds (chloroform, chlorobenzene, o-dichlorobenzene, n-heptane, toluene, n-hexane and n-octane). The film thicknesses are varied from thin

  1. Nanoparticles Affect PCR Primarily via Surface Interactions with PCR Components: Using Amino-Modified Silica-Coated Magnetic Nanoparticles as a Main Model.

    PubMed

    Bai, Yalong; Cui, Yan; Paoli, George C; Shi, Chunlei; Wang, Dapeng; Shi, Xianming

    2015-06-24

    Nanomaterials have been widely reported to affect the polymerase chain reaction (PCR). However, many studies in which these effects were observed were not comprehensive, and many of the proposed mechanisms have been primarily speculative. In this work, we used amino-modified silica-coated magnetic nanoparticles (ASMNPs, which can be collected very easily using an external magnetic field) as a model and compared them with gold nanoparticles (AuNPs, which have been studied extensively) to reveal the mechanisms by which nanoparticles affect PCR. We found that nanoparticles affect PCR primarily by binding to PCR components: (1) inhibition, (2) specifity, and (3) efficiency and yield of PCR are impacted. (1) Excess nanomaterials inhibit PCR by adsorbing to DNA polymerase, Mg(2+), oligonucleotide primers, or DNA templates. Nanoparticle surface-active groups are particularly important to this effect. (2, a) Nanomaterials do not inhibit nonspecific amplification products caused by false priming as previously surmised. It was shown that relatively low concentrations of nanoparticles inhibited the amplification of long amplicons, and increasing the amount of nanoparticles inhibited the amplification of short amplicons. This concentration phenomenon appears to be the result of the formation of "joints" upon the adsorption of ASMNPs to DNA templates. (b) Nanomaterials are able to inhibit nonspecific amplification products due to incomplete amplification by preferably adsorbing single-stranded incomplete amplification products. (3) Some types of nanomaterials, such as AuNPs, enhance the efficiency and yield of PCR because these types of nanoparticles can adsorb to single-stranded DNA more strongly than to double-stranded DNA. This behavior assists in the rapid and thorough denaturation of double-stranded DNA templates. Therefore, the interaction between the surface of nanoparticles and PCR components is sufficient to explain most of the effects of nanoparticles on PCR.

  2. Hydroxyapatite-coated total hip femoral components in patients less than fifty years old. Clinical and radiographic results after five to eight years of follow-up.

    PubMed

    Capello, W N; D'Antonio, J A; Feinberg, J R; Manley, M T

    1997-07-01

    One hundred and thirty-three patients (152 hips) who were an average of thirty-nine years old (range, sixteen to forty-nine years old) received a proximally hydroxyapatite-coated femoral prosthesis as part of a total hip arthroplasty and were followed for a minimum of five years (average, 6.4 years; range, five to 8.3 years) or until revision. The average Harris hip score was 47 points (range, 22 to 77 points) preoperatively and 93 points (range, 49 to 100 points) at the time of the latest clinical evaluation. Two patients who had a well fixed femoral implant had activity-limiting pain in the thigh at the time of the most recent examination. Radiographic changes consistent with bone-remodeling (cortical hypertrophy and bone condensation) typically were seen around the mid-part of the shaft of the prosthesis. Forty-eight (32 per cent) of the 148 hips that were included in the radiographic analysis demonstrated a small amount of erosive scalloping in either zone 1 or zone 7 of Gruen et al., and intramedullary osteolysis was suspected in only one hip. All stems were radiographically osseointegrated according to a modification of the criteria described by Engh et al. Four stems were revised, but none of the revisions were performed because of mechanical failure (two stems were revised in conjunction with a revision of the cup because of pain; one, because of an infection; and one, after a traumatic femoral fracture that occurred six years postoperatively). Thus, the rates of aseptic and mechanical failure were both 0 per cent. The combined rate of failure, which included the two stems that were revised because of pain and the two stems that were associated with pain that limited activity, was 2.6 per cent (four of 152 stems). The over-all clinical results associated with hydroxyapatite-coated femoral components were excellent in this group of young patients after intermediate-term follow-up. A review of serial radiographs showed mechanically stable implants with

  3. Tribotechnical and Mechanical Properties of Coarse-Grained and Submicrocrystalline Ti-Al-V (VT6) Alloy with a Ti-C-Mo-S Multi-Component Antifriction Coating

    NASA Astrophysics Data System (ADS)

    Potekaev, A. I.; Savostikov, V. M.; Tabachenko, A. N.; Dudarev, E. F.; Shulepov, I. A.

    2014-09-01

    The results of a comparative study of the effect of a nanophase Ti-C-Mo-S coating on tribotechnical and mechanical properties of a VT6 (α+β)-titanium alloy in its coarse-grained and submicrocrystalline states are presented. To form the coating of a Ti-C-Mo-S chemical composition, use is made of a low-temperature magnetron-plasma deposition process at the substrate temperature not higher than 300°С. With a 1-1.3μm multi-component nanophase coating, the friction coefficient in a friction pair of the like grain structure (submicrocrystalline or coarse-grained) is shown to reduce by a few factors, while the wear resistance appears to increase by two orders of magnitude. The high strength achieved in the alloy due to the formation of the submicrocrystalline structure is maintained.

  4. Process Sprays Uniforms Plasma Coatings

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.; Jacobson, T. P.; Walther, G. C.; Nakamura, H. H.

    1983-01-01

    Composite-powder processing procedure developed along with plasma-spray parameters to achieve homogeneous, well-bonded, low-porosity, self-lubricating coatings. Multicomponent plasma coatings are applied without segretation of components.

  5. Use of Refractory Nanoparticles as a Component of Welding Materials in Welding and Surfacing With Coated Electrodes and Flux Cored Wires

    NASA Astrophysics Data System (ADS)

    Kartsev, D. S.; Zernin, E. A.

    2016-08-01

    The authors address to the issue of mainstream directions and application fields of nanostructured coated electrodes and flux cored wires, their distinctive advantages and shortcomings. Some consideration is given to use of refractory nanoparticles and their influence on the structure and properties of metal when welding and surfacing with flux cored wires and coated electrodes. The results of research carried out in this sphere are analyzed.

  6. Strain isolated ceramic coatings

    NASA Technical Reports Server (NTRS)

    Tolokan, R. P.; Brady, J. B.; Jarrabet, G. P.

    1985-01-01

    Plasma sprayed ceramic coatings are used in gas turbine engines to improve component temperature capability and cooling air efficiency. A compliant metal fiber strain isolator between a plasma sprayed ceramic coating and a metal substrate improves ceramic durability while allowing thicker coatings for better insulation. Development of strain isolated coatings has concentrated on design and fabrication of coatings and coating evaluation via thermal shock testing. In thermal shock testing, five types of failure are possible: buckling failure im compression on heat up, bimetal type failure, isothermal expansion mismatch failure, mudflat cracking during cool down, and long term fatigue. A primary failure mode for thermally cycled coatings is designated bimetal type failure. Bimetal failure is tensile failure in the ceramic near the ceramic-metal interface. One of the significant benefits of the strain isolator is an insulating layer protecting the metal substrate from heat deformation and thereby preventing bimetal type failure.

  7. Thermal barrier coating

    DOEpatents

    Bowker, Jeffrey Charles; Sabol, Stephen M.; Goedjen, John G.

    2001-01-01

    A thermal barrier coating for hot gas path components of a combustion turbine based on a zirconia-scandia system. A layer of zirconium scandate having the hexagonal Zr.sub.3 Sc.sub.4 O.sub.12 structure is formed directly on a superalloy substrate or on a bond coat formed on the substrate.

  8. Sequential release kinetics of two (gentamicin and BMP-2) or three (gentamicin, IGF-I and BMP-2) substances from a one-component polymeric coating on implants.

    PubMed

    Strobel, Catrin; Bormann, Nicole; Kadow-Romacker, Anke; Schmidmaier, Gerhard; Wildemann, Britt

    2011-11-30

    The local application of antibiotics in combination with timely controlled growth factor delivery might be beneficial for the prevention of infections and to stimulate bone healing. Therefore, in this study a variable sequential drug delivery system with three distinctly different release profiles was developed: i) a burst release of gentamicin, ii) a burst release of IGF-I followed by a sustained release, and iii) a slow sustained release of BMP-2 out of an implant coating. Only one polymer [poly(D,L-lactide)], incorporating gentamicin, IGF-I or BMP-2, was used for two- or three-layer coatings of K-wires. To control the release kinetics, the polymer concentrations in the solvent were varied. The activity of early released gentamicin from a two-layer coating was confirmed microbiologically and BMP-2 stimulated the metabolic activity and alkaline phosphatase activity of C2C12 cells after 2 weeks. From the three-layer coated wires, IGF-I continuously stimulated the cell proliferation, whereas BMP-2 enhanced ALP between 1 and 3 weeks. The sequential release of growth factors revealed an additive effect on the metabolic activity and ALP of primary osteoblast-like cells compared to the single coated controls. The controlled delivery of different factors from one implant might prevent infections and subsequently stimulate the different phases of bone healing.

  9. The tribology of PS212 coatings and PM212 composites for the lubrication of titanium 6Al-4V components of a Stirling engine space power system

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.; Lukaszewicz, Victor; Dellacorte, Christopher

    1994-01-01

    The Stirling space power machine incorporates a linear alternator to generate electrical power. The alternator is a reciprocating device that is driven by a solar or nuclear-powered Stirling engine. The power piston and cylinder are made of titanium 6Al-4V (Ti6-4) alloy, and are designed to be lubricated by a hydrodynamically-generated gas film. Rubbing occurs during starts and stops and there is the possibility of an occasional high speed rub. Since titanium is known to have a severe galling tendency in sliding contacts, a 'back-up', self-lubricating coating on the cylinder and/or the piston is needed. This report describes the results of a research program to study the lubrication of Ti6-4 with the following chromium carbide based materials: plasma-sprayed PS212 coatings and sintered PM212 counterfaces. Program objectives are to achieve adherent coatings on Ti6-4 and to measure the friction and wear characteristics of the following sliding combinations under conditions simulative of the Stirling-driven space power linear alternator: Ti6-4/Ti6-4 baseline, Ti6-4/PS212-coated Ti6-4, and PS212-coated Ti6-4/PM212.

  10. Bacillus subtilis Spore Coat

    PubMed Central

    Driks, Adam

    1999-01-01

    In response to starvation, bacilli and clostridia undergo a specialized program of development that results in the production of a highly resistant dormant cell type known as the spore. A proteinacious shell, called the coat, encases the spore and plays a major role in spore survival. The coat is composed of over 25 polypeptide species, organized into several morphologically distinct layers. The mechanisms that guide coat assembly have been largely unknown until recently. We now know that proper formation of the coat relies on the genetic program that guides the synthesis of spore components during development as well as on morphogenetic proteins dedicated to coat assembly. Over 20 structural and morphogenetic genes have been cloned. In this review, we consider the contributions of the known coat and morphogenetic proteins to coat function and assembly. We present a model that describes how morphogenetic proteins direct coat assembly to the specific subcellular site of the nascent spore surface and how they establish the coat layers. We also discuss the importance of posttranslational processing of coat proteins in coat morphogenesis. Finally, we review some of the major outstanding questions in the field. PMID:10066829

  11. Super Thin Ceramic Coatings

    NASA Image and Video Library

    New technology being developed at NASA's Glenn Research Center creates super thin ceramic coatings on engine components. The Plasma Spray – Physical Vapor Deposition (PS-PVD) rig uses a powerful ...

  12. Advanced thermal barrier coating systems

    NASA Technical Reports Server (NTRS)

    Dorfman, M. R.; Reardon, J. D.

    1985-01-01

    Current state-of-the-art thermal barrier coating (TBC) systems consist of partially stabilized zirconia coatings plasma sprayed over a MCrAlY bond coat. Although these systems have excellent thermal shock properties, they have shown themselves to be deficient for a number of diesel and aircraft applications. Two ternary ceramic plasma coatings are discussed with respect to their possible use in TBC systems. Zirconia-ceria-yttria (ZCY) coatings were developed with low thermal conductivities, good thermal shock resistance and improved resistance to vanadium containing environments, when compared to the baseline yttria stabilized zirconia (YSZ) coatings. In addition, dense zirconia-titania-yttria (ZTY) coatings were developed with particle erosion resistance exceeding conventional stabilized zirconia coatings. Both coatings were evaluated in conjunction with a NiCr-Al-Co-Y2O3 bond coat. Also, multilayer or hybrid coatings consisting of the bond coat with subsequent coatings of zirconia-ceria-yttria and zirconia-titania-yttria were evaluated. These coatings combine the enhanced performance characteristics of ZCY with the improved erosion resistance of ZTY coatings. Improvement in the erosion resistance of the TBC system should result in a more consistent delta T gradient during service. Economically, this may also translate into increased component life simply because the coating lasts longer.

  13. Boron trifluoride coatings for plastics

    NASA Technical Reports Server (NTRS)

    Kubacki, R. M.

    1978-01-01

    Tough, durable coatings of boron triflouride can be deposited on plastic optical components to protect them from destructive effects of abrasion, scratching, and environment. Coating material can be applied simultaneously with organic polymers, using plasma glow-discharge methods, or it can be used as base material for other coatings to increase adhesion.

  14. Impact-Resistant Ceramic Coating

    NASA Technical Reports Server (NTRS)

    Wheeler, W. H.; Creedon, J. F.; Izu, Y. D.

    1986-01-01

    Refractory fibers more than double strength of coating. Impact strengths of ceramic coatings increase with increasing whisker content. Silicon carbide whiskers clearly produce largest increase, and improvement grows even more with high-temperature sintering. Coating also improves thermal and mechanical properties of electromagnetic components, mirrors, furnace linings, and ceramic parts of advanced internal-combustion engines.

  15. Switchable antifouling coatings and uses thereof

    DOEpatents

    Denton, Michele L. Baca; Dirk, Shawn M.; Johnson, Ross Stefan

    2017-02-28

    The present invention relates to antifouling coatings capable of being switched by using heat or ultraviolet light. Prior to switching, the coating includes an onium cation component having antimicrobial and antibacterial properties. Upon switching, the coating is converted to a conjugated polymer state, and the cationic component is released with any adsorbed biofilm layer. Thus, the coatings herein have switchable and releasable properties. Methods of making and using such coatings are also described.

  16. Nanoparticles affect PCR primarily via surface interactions with PCR components: using amino-modified silica-coated magnetic nanoparticles as a main model

    USDA-ARS?s Scientific Manuscript database

    Nanomaterials have been widely reported to affect the polymerase chain reaction (PCR). However, many studies in which these effects were observed were not comprehensive, and many of the proposed mechanisms have been primarily speculative. In this work, we used amino-modified silica-coated magnetic n...

  17. Hot Corrosion Resistance and Mechanical Behavior of Atmospheric Plasma Sprayed Conventional and Nanostructured Zirconia Coatings

    NASA Astrophysics Data System (ADS)

    Saremi, Mohsen; Keyvani, Ahmad; Heydarzadeh Sohi, Mahmoud

    Conventional and nanostructured zirconia coatings were deposited on In-738 Ni super alloy by atmospheric plasma spray technique. The hot corrosion resistance of the coatings was measured at 1050°C using an atmospheric electrical furnace and a fused mixture of vanadium pent oxide and sodium sulfate respectively. According to the experimental results nanostructured coatings showed a better hot corrosion resistance than conventional ones. The improved hot corrosion resistance could be explained by the change of structure to a dense and more packed structure in the nanocoating. The evaluation of mechanical properties by nano indentation method showed the hardness (H) and elastic modulus (E) of the YSZ coating increased substantially after hot corrosion.

  18. The use of uncemented extensively porous-coated femoral components in the management of Vancouver B2 and B3 periprosthetic femoral fractures.

    PubMed

    O'Shea, K; Quinlan, J F; Kutty, S; Mulcahy, D; Brady, O H

    2005-12-01

    We assessed the outcome of patients with Vancouver type B2 and B3 periprosthetic fractures treated with femoral revision using an uncemented extensively porous-coated implant. A retrospective clinical and radiographic assessment of 22 patients with a mean follow-up of 33.7 months was performed. The mean time from the index procedure to fracture was 10.8 years. There were 17 patients with a satisfactory result. Complications in four patients included subsidence in two, deep sepsis in one, and delayed union in one. Concomitant acetabular revision was required in 19 patients. Uncemented extensively porous-coated femoral stems incorporate distally allowing stable fixation. We found good early survival rates and a low incidence of nonunion using this implant.

  19. Laser Consolidation - A Novel One-Step Manufacturing Process for Making Net-Shape Functional Components

    DTIC Science & Technology

    2006-05-01

    addition , this computer-aided manufacturing process provides an excellent opportunity for manufacturing complex parts that are difficult to make by...consolidation process, more unique features can be added to the components to provide additional functionality, reduce manufacturing time and cost...Functional Prototypes IN-625 alloy 316L S.S Stellite 6 alloy LC IN-738 Applications - Manufacturing Complex Net-Shape Parts LC IN-625LC IN-625 Applications

  20. HVOF Thermal Spray TiC/TiB2 Coatings for AUSC Boiler/Turbine Components for Enhanced Corrosion Protection

    SciTech Connect

    Mondal, Kanchan; Koc, Rasit; Fan, Chinbay

    2016-12-07

    The high temperatures of operations still pose significant risk of degradation and fatigue from oxidizing, corroding and eroding environment. In addition to unused O2, water from combustion and SOx from the coal sulfur oxidation that result in highly corrosive environment, acid gases such as HCl and other sulfur compounds may also be present. These adverse effects are further accelerated due to the elevated temperatures. In addition, ash particulates and unburnt carbon and pyritic sulfur can cause erosion of the surface and thus loss of material. Unburnt carbon and pyritic sulfur may also cause localized reduction sites. Thus, fireside corrosion protection and steam oxidation protection alternatives to currently used Ni-Cr overlays need to be identified and evaluated. Titanium carbide (TiC) is a suitable alternative on account of the material features such as the high hardness, the high melting point, the high strength and the low density for the substitution or to be used in conjunction with NiCr for enhancing the fireside corrosion and erosion of the materials. Another alternative is the use of titanium boride as a coating for chemical stability required for long-term service and high erosion resistance over the state-of-the-art, high fracture toughness (K1C ~12 MPam1/2) and excellent corrosion resistance (kp~1.9X10-11 g2/cm4/s at 800°C in air). The overarching aim of the research endeavor was to synthesize oxidation, corrosion and wear resistant TiC and TiB2 coating powders, apply thermal spray coating on existing boiler materials and characterize the coated substrates for corrosion resistance for applications at high temperatures (500 -750 °C) and high pressures (~350 bars) using the HVOF process and to demonstrate the feasibility of these coating to be used in AUSC boilers and turbines.

  1. Use of total internal reflection Raman (TIR) and attenuated total reflection infrared (ATR-IR) spectroscopy to analyze component separation in thin offset ink films after setting on coated paper surfaces.

    PubMed

    Kivioja, Antti; Hartus, Timo; Vuorinen, Tapani; Gane, Patrick; Jääskeläinen, Anna-Stiina

    2013-06-01

    The interactive behavior of ink constituents with porous substrates during and after the offset print process has an important effect on the quality of printed products. To help elucidate the distribution of ink components between the retained ink layer and the substrate, a variety of spectroscopic and microscopic analysis techniques have been developed. This paper describes for the first time the use of total internal reflection (TIR) Raman spectroscopy to analyze the penetration behavior of separated offset ink components (linseed oil, solid color pigment) in coated papers providing chemically intrinsic information rapidly, nondestructively, and with minimal sample preparation. In addition, the already widely applied technique of attenuated total reflection infrared spectroscopy (ATR-IR) was evaluated in parallel and compared. The results of the ATR-IR Raman clearly revealed an improvement in uppermost depth resolution compared with values previously published from other nondestructive techniques, and the method is shown to be capable of providing new knowledge of the setting of thin (0.25-2 μm) offset ink films, allowing the spreading and the penetration behavior on physically different paper coating surfaces to be studied.

  2. COATED ALLOYS

    DOEpatents

    Harman, C.G.; O'Bannon, L.S.

    1958-07-15

    A coating is described for iron group metals and alloys, that is particularly suitable for use with nickel containing alloys. The coating is glassy in nature and consists of a mixture containing an alkali metal oxide, strontium oxide, and silicon oxide. When the glass coated nickel base metal is"fired'' at less than the melting point of the coating, it appears the nlckel diffuses into the vitreous coating, thus providing a closely adherent and protective cladding.

  3. Aluminide coatings

    DOEpatents

    Henager, Jr; Charles, H [Kennewick, WA; Shin, Yongsoon [Richland, WA; Samuels, William D [Richland, WA

    2009-08-18

    Disclosed herein are aluminide coatings. In one embodiment coatings are used as a barrier coating to protect a metal substrate, such as a steel or a superalloy, from various chemical environments, including oxidizing, reducing and/or sulfidizing conditions. In addition, the disclosed coatings can be used, for example, to prevent the substantial diffusion of various elements, such as chromium, at elevated service temperatures. Related methods for preparing protective coatings on metal substrates are also described.

  4. Spray-Deposited Superconductor/Polymer Coatings

    NASA Technical Reports Server (NTRS)

    Wise, Stephanie A.; Tran, Sang Q.; Hooker, Matthew W.

    1993-01-01

    Coatings that exhibit the Meissner effect formed at relatively low temperature. High-temperature-superconductor/polymer coatings that exhibit Meissner effect deposited onto components in variety of shapes and materials. Simple, readily available equipment needed in coating process, mean coatings produced economically. Coatings used to keep magnetic fields away from electronic circuits in such cryogenic applications as magnetic resonance imaging and detection of infrared, and in magnetic suspensions to provide levitation and/or damping of vibrations.

  5. Spray-Deposited Superconductor/Polymer Coatings

    NASA Technical Reports Server (NTRS)

    Wise, Stephanie A.; Tran, Sang Q.; Hooker, Matthew W.

    1993-01-01

    Coatings that exhibit the Meissner effect formed at relatively low temperature. High-temperature-superconductor/polymer coatings that exhibit Meissner effect deposited onto components in variety of shapes and materials. Simple, readily available equipment needed in coating process, mean coatings produced economically. Coatings used to keep magnetic fields away from electronic circuits in such cryogenic applications as magnetic resonance imaging and detection of infrared, and in magnetic suspensions to provide levitation and/or damping of vibrations.

  6. Low Conductivity Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming

    2005-01-01

    Thermal barrier coatings will be more aggressively designed to protect gas turbine engine hot-section components in order to meet future engine higher fuel efficiency and lower emission goals. In this presentation, thermal barrier coating development considerations and requirements will be discussed. An experimental approach is established to monitor in real time the thermal conductivity of the coating systems subjected to high-heat-flux, steady-state and cyclic temperature gradients. Advanced low conductivity thermal barrier coatings have also been developed using a multi-component defect clustering approach, and shown to have improved thermal stability. The durability and erosion resistance of low conductivity thermal barrier coatings have been improved utilizing advanced coating architecture design, composition optimization, in conjunction with more sophisticated modeling and design tools.

  7. Enhanced Droplet Erosion Resistance of Laser Treated Nano Structured TWAS and Plasma Ion Nitro-Carburized Coatings for High Rating Steam Turbine Components

    NASA Astrophysics Data System (ADS)

    Pant, B. K.; Arya, Vivek; Mann, B. S.

    2010-09-01

    This article deals with surface modification of twin wire arc sprayed (TWAS) and plasma ion nitro-carburized X10CrNiMoV1222 steel using high power diode laser (HPDL) to overcome water droplet erosion occurring in low pressure steam turbine (LPST) bypass valves and LPST moving blades used in high rating conventional, critical, and super critical thermal power plants. The materials commonly used for high rating steam turbines blading are X10CrNiMoV1222 steel and Ti6Al4V titanium alloy. The HPDL surface treatment on TWAS coated X10CrNiMoV1222 steel as well as on plasma ion nitro-carburized steel has improved water droplet resistance manifolds. This may be due to combination of increased hardness and toughness as well as the formation of fine grained structure due to rapid heating and cooling rates associated with the laser surface treatment. The water droplet erosion test results along with their damage mechanism are reported in this article.

  8. Coating Reduces Ice Adhesion

    NASA Technical Reports Server (NTRS)

    Smith, Trent; Prince, Michael; DwWeese, Charles; Curtis, Leslie

    2008-01-01

    The Shuttle Ice Liberation Coating (SILC) has been developed to reduce the adhesion of ice to surfaces on the space shuttle. SILC, when coated on a surface (foam, metal, epoxy primer, polymer surfaces), will reduce the adhesion of ice by as much as 90 percent as compared to the corresponding uncoated surface. This innovation is a durable coating that can withstand several cycles of ice growth and removal without loss of anti-adhesion properties. SILC is made of a binder composed of varying weight percents of siloxane(s), ethyl alcohol, ethyl sulfate, isopropyl alcohol, and of fine-particle polytetrafluoroethylene (PTFE). The combination of these components produces a coating with significantly improved weathering characteristics over the siloxane system alone. In some cases, the coating will delay ice formation and can reduce the amount of ice formed. SILC is not an ice prevention coating, but the very high water contact angle (greater than 140 ) causes water to readily run off the surface. This coating was designed for use at temperatures near -170 F (-112 C). Ice adhesion tests performed at temperatures from -170 to 20 F (-112 to -7 C) show that SILC is a very effective ice release coating. SILC can be left as applied (opaque) or buffed off until the surface appears clear. Energy dispersive spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS) data show that the coating is still present after buffing to transparency. This means SILC can be used to prevent ice adhesion even when coating windows or other objects, or items that require transmission of optical light. Car windshields are kept cleaner and SILC effectively mitigates rain and snow under driving conditions.

  9. Selective oxidation of cube textured Ni and Ni-Cr substrate for the formation of cube textured NiO as a component buffer layer for REBa 2Cu 3O 7+ x (REBCO) coated conductors

    NASA Astrophysics Data System (ADS)

    Lockman, Z.; Goldacker, W.; Nast, R.; deBoer, B.; MacManus-Driscoll, J. L.

    2002-08-01

    Thermal oxidation of cube textured, pure Ni and Ni-Cr tapes was undertaken under different oxidation conditions to form cube textured NiO for the use as a first component of buffer layer for the coated conductor. Cube textured NiO was formed on pure Ni after oxidising for more than 130 min in O 2 at 1250 °C. The oxide thickness was >30 μm. Much shorter oxidation times (20-40 min, NiO thickness of ∼5 μm) and lower temperature (1050 °C) were required to form a similar texture on Ni-Cr foils. In addition, NiO formed on Ni-13%Cr was more highly textured than Ni-10%Cr. A Cr 2O 3 inner layer and NiO outer layer was formed on the Ni-Cr alloys.

  10. Palladium-modified aluminide coatings: Mechanisms of formation

    SciTech Connect

    Lamesle, P.; Steinmetz, P.; Steinmetz, J.; Alperine, S.

    1995-02-01

    The need to increase the efficiency of turbo engines has led manufacturers to increase the temperature of gases at the exhaust of the combustion chamber. Another limiting factor for the lifetime of blades or vanes used in gas turbines is hot corrosion due to the condensation of alkaline sulfate produced by the oxidation of sulfur contained in kerosene or fuels. To overcome these problems, the use of protective coatings has come into general use. A systematic investigation of the influence of Pd-Ni predeposit alloys on the microstructure and composition of aluminum diffusion coatings has been conducted on Ni base superalloys (mainly IN738). Their metallurgical structure has been studied with a special emphasis on the nature of the phases and distribution of the various elements throughout the coating section. A two-layer structure similar to that formed on simple aluminide coatings is observed whatever the type of aluminizing treatment (low and high aluminum activity, pack of vapor-phase coating). The superficial layer is, however, very different from that observed in simple aluminide coatings, since it is constituted with a ternary PdNi aluminide. Palladium concentration profiles, which significantly differ when using low or high activity cements, and the results of a study of the ternary Ni-Pd-Al phase diagram, provide qualitative indications concerning the coatings` growth processes. Palladium, if present at a sufficient level, enhances Al diffusion in the beta phase. In the case of low activity processes, a consequence of this increase of Al diffusion flux is the location of an NiAl reaction zone inside the coating.

  11. Absorptive coating for aluminum solar panels

    NASA Technical Reports Server (NTRS)

    Desmet, D.; Jason, A.; Parr, A.

    1979-01-01

    Method for coating forming coating of copper oxide from copper component of sheet aluminum/copper alloy provides strong durable solar heat collector panels. Copper oxide coating has solar absorption characteristics similar to black chrome and is much simpler and less costly to produce.

  12. Engineering coatings: Design and application. Second edition

    SciTech Connect

    Grainger, S.; Blunt, J.

    1999-07-01

    This is a guidebook for coating selection and the means of application for specific circumstances. Mechanisms of wear and corrosion are discussed in detail to assist in the analysis of component failures and newly designed parts. Coverage includes coating finishing, quality assurance, health and safety issues and other useful reference information for designers and surface engineers who use or select coatings.

  13. Absorptive coating for aluminum solar panels

    NASA Technical Reports Server (NTRS)

    Desmet, D.; Jason, A.; Parr, A.

    1979-01-01

    Method for coating forming coating of copper oxide from copper component of sheet aluminum/copper alloy provides strong durable solar heat collector panels. Copper oxide coating has solar absorption characteristics similar to black chrome and is much simpler and less costly to produce.

  14. Coatings for High-Temperature Vibration Damping of Turbines

    DTIC Science & Technology

    2009-10-01

    damping is provided by both the thin bond- coat and thermal barrier coating (TBC) in TBC coated superalloy system, (ii) the damping from each component...bond- coat and the TBC itself, and (iii) damping from EB-PVD deposited TBCs and platinum-modified nickel aluminide bond- coats occur at the same...closer to chemical equilibrium with existing superalloys than those currently used as bond- coats . Also, depending on the platinum content, the nickel

  15. Thermo-mechanical Fatigue Failure of Thermal Barrier Coated Superalloy Specimen

    NASA Astrophysics Data System (ADS)

    Subramanian, Rajivgandhi; Mori, Yuzuru; Yamagishi, Satoshi; Okazaki, Masakazu

    2015-09-01

    Failure behavior of thermal barrier coated (TBC) Ni-based superalloy specimens were studied from the aspect of the effect of bond coat material behavior on low cycle fatigue (LCF) and thermo-mechanical fatigue (TMF) at various temperatures and under various loading conditions. Initially, monotonic tensile tests were carried out on a MCrAlY alloy bond coat material in the temperature range of 298 K to 1273 K (25 °C to 1000 °C). Special attention was paid to understand the ductile to brittle transition temperature (DBTT). Next, LCF and TMF tests were carried out on the thermal barrier coated Ni-based alloy IN738 specimen. After these tests, the specimens were sectioned to understand their failure mechanisms on the basis of DBTT of the bond coat material. Experimental results demonstrated that the LCF and TMF lives of the TBC specimen were closely related to the DBTT of the bond coat material, and also the TMF lives were different from those of LCF tests. It has also been observed that the crack density in the bond coat in the TBC specimen was significantly dependent on the test conditions. More importantly, not only the number of cracks but also the crack penetration probability into substrate were shown to be sensitive to the DBTT.

  16. Vacuum Plasma Sprayed Metallic Coatings

    NASA Astrophysics Data System (ADS)

    Shankar, S.; Koenig, D. E.; Dardi, L. E.

    1981-10-01

    Recognizing the fundamental cost advantage, technical capabilities, and compositional flexibility of reduced pressure (vacuum) plasma spraying compared to other overlay coating methods, an advanced, second generation, closed chamber deposition process called VPX (a Howmet trademark) was developed. An automated experimental facility for coating gas turbine engine components was also constructed. This paper describes several important features of the process and equipment. It shows that the use of optimized spray parameters combined with an appropriate schedule of relative orientations between the gun and work-piece can be used to produce dense and highly reproducible coatings of either uniform or controlled thickness distributions. The chemical composition, microstructure, and interfacial characteristics of typical MCrAlY coatings are reported. Some effects of operating procedures and MCrAlY chemical composition on coating density are noted. The results of mechanical property and burner rig tests of coated material are also described.

  17. Oxidation resistance of Al2O3-nanostructured/CSZ composite compared to conventional CSZ and YSZ thermal barrier coatings

    NASA Astrophysics Data System (ADS)

    Keyvani, A.; Bahamirian, M.

    2016-10-01

    Thermal barrier coatings are widely used in combustion sections of turbine engines, however, their main disadvantage is the spallation from the bond coat, occurring due to oxidation and formation of thermally grown oxide (TGO). In this paper, the oxidation resistance of yttria stabilized zirconia (YSZ), ceria stabilized zirconia (CSZ), and Al2O3-nanostructured/CSZ composite coatings have been studied and compared with each other. Samples were heated in air at 1100 °C using an electrical furnace. Three types of the top coats were applied by thermal spray technique on IN738LC base metal. Scanning electron microscopy was used to study the microstructure of the coatings before and after the oxidation. The experimental results showed that Al2O3-nanostructured/CSZ composite coating exhibits considerably better oxidation resistance compared to conventional YSZ and CSZ coatings. The microstructural analysis indicated a smaller growth of TGO in the Al2O3-nanostructured/CSZ composite coating, improving the oxidation resistance of the coating.

  18. Hydroxyapatite coatings.

    PubMed

    Lacefield, W R

    1988-01-01

    Four coating techniques were evaluated to determine which is most suitable for producing a dense, highly adherent coating onto metallic and ceramic implant materials. Two of the selected coating methods have serious limitations for use in this particular application, and did not meet the specified criteria for satisfactory coating as defined in the initial stages of the study. For example, the dip coating-sintering technique was judged to be unsatisfactory because of the adverse effect of the high-temperature sintering cycle on the mechanical properties of the metallic substrate materials. These materials could not be used in load-bearing applications because of the excessive grain growth and loss of the wrought structure of both the commercially pure Ti and Ti-6Al-4V substrates, and the loss of ductility in the cast Co-Cr-Mo alloy. Another area of concern was that bond strength between the HA coating and the substrate was not high enough to insure that interfacial failure would not occur during the lifetime of the implant. The immersion-coating technique, in which the metal substrate is immersed into the molten ceramic, was shown in a previous study to be the best method of coating a bioreactive glass onto a Co-Cr-Mo implant. Heating HA above its melting temperature, however, caused undesired compositional and structural changes, and upon solidification very limited adherence between the modified ceramic and substrate material occurred under the conditions of this study. The HIP technique, in which the Ti powder substrate and the HA powder coating are sintered together in a high-pressure autoclave, shows great promise for the fabrication of high-quality composite implants. Initial studies have indicated that high-density Ti substrates with a small grain size that are well bonded to a dense HA coating can be produced under optimum conditions. Sintering and densification additives, such as SiO2 powder, do not appear to be necessary. The main drawback to this

  19. Process for Coating Substrates with Catalytic Materials

    NASA Technical Reports Server (NTRS)

    Klelin, Ric J. (Inventor); Upchurch, Billy T. (Inventor); Schryer, David R. (Inventor)

    2004-01-01

    A process for forming catalysts by coating substrates with two or more catalytic components, which comprises the following sequence of steps. First, the substrate is infused with an adequate amount of solution having a starting material comprising a catalytic component precursor, wherein the thermal decomposition product of the catalytic component precursor is a catalytic component. Second, the excess of the solution is removed from the substrate. thereby leaving a coating of the catalytic component precursor on the surface of the substrate. Third, the coating of the catalytic component precursor is converted to the catalytic component by thermal decomposition. Finally, the coated substance is etched to increase the surface area. The list three steps are then repeated for at least a second catalytic component. This process is ideally suited for application in producing efficient low temperature oxidation catalysts.

  20. Coating for prevention of titanium combustion

    NASA Technical Reports Server (NTRS)

    Anderson, V. G.; Funkhouser, M.; Mcdaniel, P.

    1980-01-01

    A limited number of coating options for titanium gas turbine engine components were explored with the objective of minimizing potential combustion initiation and propagation without adversely affecting component mechanical properties. Objectives were met by two of the coatings, ion-plated platinum plus electroplated copper plus electroplated nickel and ion vapor deposited aluminum.

  1. Improved metallic and thermal barrier coatings

    NASA Technical Reports Server (NTRS)

    Stecura, S.

    1981-01-01

    Low thermal conductivity two layer ceramic coatings are efficient thermal barriers between cooled matallic components and high temperature combustion gases. Potential components are combustors, blades, and vanes in aircraft engines of power-generating turbines. Presence of two layer coatings greatly reduces temperature and coolant requirements.

  2. Enhanced electrochemical performance of Li-rich layered cathode materials via chemical activation of Li2MnO3 component and formation of spinel/carbon coating layer

    NASA Astrophysics Data System (ADS)

    Pang, Shengli; Xu, Kaijie; Wang, Yonggang; Shen, Xiangqian; Wang, Wenzhi; Su, Yanjing; Zhu, Meng; Xi, Xiaoming

    2017-10-01

    Li-rich layered oxides are promising cathode materials for advanced Li-ion batteries because of their high specific capacity and operating potential. In this work, the Li-rich layered oxide Li1·2Mn0·54Ni0·13Co0·13O2 (LMNC), is modified via a carbonization-reduction process (yielding the corresponding reduced compound denoted LMNC-R). Compared to the pristine oxide, LMNC-R delivers significantly enhanced initial discharge capacity/columbic efficiency, remarkably improved rate performance with an accelerated Li+ diffusion rate, and significantly increased capacity/voltage retention. The specific energy density and energy retention after 100 cycles increase from 378.2 Wh kg-1 and 47.7% for LMNC to 572.0 Wh kg-1 and 71.3%, respectively, for LMNC-R. The enhancement in the electrochemical performance of LMNC-R can be attributed to the synchronous formation of the oxygen non-stoichiometric Li2MnO3-δ component and to the carbon/spinel double coating layer in the material that resulted from the post-treatment process. Thus, the carbonization-reduction modification process can be used to tailor the structural evolution procedure and to suppress the metal ion dissolution of the Li-rich layered oxide during cycling.

  3. Regulatory Aspects of Coatings

    USDA-ARS?s Scientific Manuscript database

    This chapter gives a history of the development and uses of edible coating regulations, detailed chapters on coating caracteristics, determination of coating properties, methods for making coatings, and discription of coating film formers (polysaccharieds, lipids, resins, proteins). The chapter also...

  4. Protective coatings for concrete

    SciTech Connect

    NAGY, KATHRYN L.; CYGAN, RANDALL T.; BRINKER, C. JEFFREY; SELLINGER, ALAN

    2000-05-01

    The new two-layer protective coating developed for monuments constructed of limestone or marble was applied to highway cement and to tobermorite, a component of cement, and tested in batch dissolution tests. The goal was to determine the suitability of the protective coating in retarding the weathering rate of concrete construction. The two-layer coating consists of an inner layer of aminoethylaminopropylsilane (AEAPS) applied as a 25% solution in methanol and an outer layer of A2** sol-gel. In previous work, this product when applied to calcite powders, had resulted in a lowering of the rate of dissolution by a factor of ten and was shown through molecular modeling to bind strongly to the calcite surface, but not too strongly so as to accelerate dissolution. Batch dissolution tests at 22 C of coated and uncoated tobermorite (1.1 nm phase) and powdered cement from Gibson Blvd. in Albuquerque indicated that the coating exhibits some protective behavior, at least on short time scales. However, the data suggest that the outer layer of sol-gel dissolves in the high-pH environment of the closed system of cement plus water. Calculated binding configuration and energy of AEAPS to the tobermorite surface suggests that AEAPS is well-suited as the inner layer binder for protecting tobermorite.

  5. Sodium sulfur container with chromium/chromium oxide coating

    DOEpatents

    Ludwig, Frank A.; Higley, Lin R.

    1981-01-01

    A coating of chromium/chromium oxide is disclosed for coating the surfaces of electrically conducting components of a sodium sulfur battery. This chromium/chromium oxide coating is placed on the surfaces of the electrically conducting components of the battery which are in contact with molten polysulfide and sulfur reactants during battery operation.

  6. Thermal Spraying Coatings Assisted by Laser Treatment

    NASA Astrophysics Data System (ADS)

    Fenineche, N. E.; Cherigui, M.

    2008-09-01

    Coatings produced by air plasma spraying (APS) are widely used to protect components against abrasive wear and corrosion. However, APS coatings contain porosities and the properties of these coatings may thereby be reduced. To improve these properties, various methods could be proposed, including post-laser irradiation [1-4]. Firstly, PROTAL process (thermal spraying assisted by laser) has been developed as a palliative technique to degreasing and grit-blasting prior to thermal spraying. Secondly, thermal spray coatings are densified and remelted using Laser treatment. In this study, a review of microstructure coatings prepared by laser-assisted air plasma spraying will be presented. Mechanical and magnetic properties will be evaluated in relation to changes in the coating microstructure and the properties of such coatings will be compared with those of as-sprayed APS coatings.

  7. Improving thermal barrier coatings by laser remelting.

    PubMed

    Múnez, C J; Gómez-García, J; Sevillano, F; Poza, P; Utrilla, M V

    2011-10-01

    Thermal barrier coatings are extensively used to protect metallic components in applications where the operating conditions include aggressive environment at high temperatures. These coatings are usually processed by thermal spraying techniques and the resulting microstructure includes thin and large splats, associated with the deposition of individual droplets, with porosity between splats. This porosity reduces the oxidation and corrosion resistance favouring the entrance of aggressive species during service. To overcome this limitation, the top coat could be modified by laser glazing reducing surface roughness and sealing open porosity. ZrO2(Y2O3) top coat and NiCrAlY bond coating were air plasma sprayed onto an Inconel 600 Ni base alloy. The top coat was laser remelted and a densified ceramic layer was induced in the top surface of the ceramic coating. This layer inhibited the ingress of aggressive species and delayed bond coat oxidation.

  8. Thermal Spraying Coatings Assisted by Laser Treatment

    SciTech Connect

    Fenineche, N. E.; Cherigui, M.

    2008-09-23

    Coatings produced by air plasma spraying (APS) are widely used to protect components against abrasive wear and corrosion. However, APS coatings contain porosities and the properties of these coatings may thereby be reduced. To improve these properties, various methods could be proposed, including post-laser irradiation [1-4]. Firstly, PROTAL process (thermal spraying assisted by laser) has been developed as a palliative technique to degreasing and grit-blasting prior to thermal spraying. Secondly, thermal spray coatings are densified and remelted using Laser treatment. In this study, a review of microstructure coatings prepared by laser-assisted air plasma spraying will be presented. Mechanical and magnetic properties will be evaluated in relation to changes in the coating microstructure and the properties of such coatings will be compared with those of as-sprayed APS coatings.

  9. Versatile Coating

    NASA Technical Reports Server (NTRS)

    1990-01-01

    A radome at Logan Airport and a large parabolic antenna at the Wang Building in Massachusetts are protected from weather, corrosion and ultraviolet radiation by a coating, specially designed for antennas and radomes, known as CRC Weathertite 6000. The CRC 6000 line that emerged from Boyd Coatings Research Co., Inc. is a solid dispersion of fluorocarbon polymer and polyurethane that yields a tough, durable film with superior ultraviolet resistance and the ability to repel water and ice over a long term. Additionally, it provides resistance to corrosion, abrasion, chemical attacks and impacts. Material can be used on a variety of substrates, such as fiberglass, wood, plastic and concrete in addition to steel and aluminum. In addition Boyd Coatings sees CRC 6000 applicability as an anti-icing system coated on the leading edge of aircraft wings.

  10. Protective Coating

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Inorganic Coatings, Inc.'s K-Zinc 531 protective coating is water-based non-toxic, non-flammable and has no organic emissions. High ratio silicate formula bonds to steel, and in 30 minutes, creates a very hard ceramic finish with superior adhesion and abrasion resistance. Improved technology allows application over a minimal commercial sandblast, fast drying in high humidity conditions and compatibility with both solvent and water-based topcoats. Coating is easy to apply and provides long term protection with a single application. Zinc rich coating with water-based potassium silicate binder offers cost advantages in materials, labor hours per application, and fewer applications over a given time span.

  11. Battery components employing a silicate binder

    DOEpatents

    Delnick, Frank M [Albuquerque, NM; Reinhardt, Frederick W [Albuquerque, NM; Odinek, Judy G [Rio Rancho, NM

    2011-05-24

    A battery component structure employing inorganic-silicate binders. In some embodiments, casting or coating of components may be performed using aqueous slurries of silicates and electrode materials or separator materials.

  12. Vacuum deposited optical coatings experiment

    NASA Technical Reports Server (NTRS)

    Charlier, Jean

    1992-01-01

    The 138-4 Frecopa experiment consisted of 20 sorts of optical components and coatings subjected to space exposure. They covered a large range of use from the UV to IR spectrum: filters, mirrors, dichroics, beam splitters, and antireflection coatings made of several different materials as layers and substrates. By comparing pre- and post-flight spectral performances, it was possible to put into evidence the alterations due to space exposure.

  13. Nanostructured diamond coatings for orthopaedic applications

    PubMed Central

    CATLEDGE, S.A.; THOMAS, V.; VOHRA, Y.K.

    2013-01-01

    With increasing numbers of orthopaedic devices being implanted, greater emphasis is being placed on ceramic coating technology to reduce friction and wear in mating total joint replacement components, in order to improve implant function and increase device lifespan. In this chapter, we consider ultra-hard carbon coatings, with emphasis on nanostructured diamond, as alternative bearing surfaces for metallic components. Such coatings have great potential for use in biomedical implants as a result of their extreme hardness, wear resistance, low friction and biocompatibility. These ultra-hard carbon coatings can be deposited by several techniques resulting in a wide variety of structures and properties. PMID:25285213

  14. Nanostructured diamond coatings for orthopaedic applications.

    PubMed

    Catledge, S A; Thomas, V; Vohra, Y K

    2013-01-01

    With increasing numbers of orthopaedic devices being implanted, greater emphasis is being placed on ceramic coating technology to reduce friction and wear in mating total joint replacement components, in order to improve implant function and increase device lifespan. In this chapter, we consider ultra-hard carbon coatings, with emphasis on nanostructured diamond, as alternative bearing surfaces for metallic components. Such coatings have great potential for use in biomedical implants as a result of their extreme hardness, wear resistance, low friction and biocompatibility. These ultra-hard carbon coatings can be deposited by several techniques resulting in a wide variety of structures and properties.

  15. Kinetic regulation of coated vesicle secretion

    PubMed Central

    Foret, Lionel; Sens, Pierre

    2008-01-01

    The secretion of vesicles for intracellular transport often relies on the aggregation of specialized membrane-bound proteins into a coat able to curve cell membranes. The nucleation and growth of a protein coat is a kinetic process that competes with the energy-consuming turnover of coat components between the membrane and the cytosol. We propose a generic kinetic description of coat assembly and the formation of coated vesicles and discuss its implication to the dynamics of COP vesicles that traffic within the Golgi and with the endoplasmic reticulum. We show that stationary coats of fixed area emerge from the competition between coat growth and the recycling of coat components, in a fashion resembling the treadmilling of cytoskeletal filaments. We further show that the turnover of coat components allows for a highly sensitive switching mechanism between a quiescent and a vesicle producing membrane, upon a slowing down of the exchange kinetics. We claim that the existence of this switching behavior, also triggered by factors, such as the presence of cargo and variation of the membrane mechanical tension, allows for efficient regulation of vesicle secretion. We propose a model, supported by different experimental observations, in which vesiculation of secretory membranes is impaired by the energy-consuming desorption of coat proteins, until the presence of cargo or other factors triggers a dynamical switch into a vesicle producing state. PMID:18824695

  16. 21 CFR 175.390 - Zinc-silicon dioxide matrix coatings.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Zinc-silicon dioxide matrix coatings. 175.390... COATINGS Substances for Use as Components of Coatings § 175.390 Zinc-silicon dioxide matrix coatings. Zinc... water washing. Silica gel Sodium silicate Zinc, as particulate metal (d) The coating in the finished...

  17. 21 CFR 175.390 - Zinc-silicon dioxide matrix coatings.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Zinc-silicon dioxide matrix coatings. 175.390... COATINGS Substances for Use as Components of Coatings § 175.390 Zinc-silicon dioxide matrix coatings. Zinc... water washing. Silica gel Sodium silicate Zinc, as particulate metal (d) The coating in the finished...

  18. 21 CFR 175.230 - Hot-melt strippable food coatings.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hot-melt strippable food coatings. 175.230 Section... COATINGS Substances for Use as Components of Coatings § 175.230 Hot-melt strippable food coatings. Hot-melt strippable food coatings may be safely applied to food, subject to the provisions of this section. (a)...

  19. 21 CFR 175.230 - Hot-melt strippable food coatings.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Hot-melt strippable food coatings. 175.230 Section... COATINGS Substances for Use as Components of Coatings § 175.230 Hot-melt strippable food coatings. Hot-melt strippable food coatings may be safely applied to food, subject to the provisions of this section. (a)...

  20. 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.

  1. Protective Coatings

    NASA Technical Reports Server (NTRS)

    1980-01-01

    General Magnaplate Corporation's pharmaceutical machine is used in the industry for high speed pressing of pills and capsules. Machine is automatic system for molding glycerine suppositories. These machines are typical of many types of drug production and packaging equipment whose metal parts are treated with space spinoff coatings that promote general machine efficiency and contribute to compliance with stringent federal sanitation codes for pharmaceutical manufacture. Collectively known as "synergistic" coatings, these dry lubricants are bonded to a variety of metals to form an extremely hard slippery surface with long lasting self lubrication. The coatings offer multiple advantages; they cannot chip, peel or be rubbed off. They protect machine parts from corrosion and wear longer, lowering maintenance cost and reduce undesired heat caused by power-robbing friction.

  2. Nanostructured Coatings

    NASA Astrophysics Data System (ADS)

    Rivière, J.-P.

    In many branches of technology where surfaces are playing a growing role, the use of coatings is often the only way to provide surfaces with specific functional properties. For example, the austenitic stainless steels or titanium alloys exhibit poor resistance to wear and low hardness values, which limits the field of applications. The idea then is to develop new solutions which would improve the mechanical performance and durability of objects used in contact and subjected to mechanical forces in hostile gaseous or liquid environments. Hard coatings are generally much sought after to enhance the resistance to wear and corrosion. They are of particular importance because they constitute a class of protective coatings which is already widely used on an industrial scale to improve the hardness and lifetime of cutting tools.

  3. Composite coatings improve engines

    SciTech Connect

    Funatani, K.; Kurosawa, K. )

    1994-12-01

    About 40% of the power loss in engine systems is attributed to the adverse effects of friction in reciprocating engine components. Over half of this power loss is caused by friction between pistons, piston rings, and cylinder bores. In addition, engine parts may be attacked by corrosive gasoline substitutes such as liquid propane gas and alcohol/gasoline mixtures. To solve both friction and corrosion problems, Nihon Parkerizing Co. has improved the nickel-phosphorus based ceramic composite (NCC) plating technology that was developed for cylinder bores and pistons by Suzuki Motor Co. in the mid 1970s. Iron and nickel-based composite plating technologies have been investigated since the early 1970s, and a few have been used on small two-stroke motorcycle, outboard marine, snowmobile, and some luxury passenger car engine components. Both nickel- and iron-base plating processes are used on cylinders and pistons because they offer excellent wear and corrosion resistance. Nickel-base films have higher corrosion resistance than those based on iron, and are capable of withstanding the corrosive conditions characteristic of high methanol fuels. Unfortunately, they experience a decrease in hardness as operating temperatures increase. However, NCC coatings with phosphorus additions have high hardness even under severe operating conditions, and hardness increases upon exposure to elevated temperatures. In addition to high hardness and corrosion resistance, NCC coatings provide a low friction coefficient, which contributes to the reduction of friction losses between sliding components. When used in low-quality or alcohol fuels, the corrosion resistance of NCC coatings is far higher than that of Fe-P plating. Additionally, the coatings reduce wall and piston temperature, wear of ring groove and skirt, and carbon deposit formation, and they improve output power and torque. These advantages all contribute to the development of light and efficient engines with better fuel mileage.

  4. Biodegradation of polymer coatings

    SciTech Connect

    Jones, W.R.; Walch, M. |; Jones-Meehan, J.

    1994-12-31

    Conventional paint removal methods include chemical stripping with VOCs blasting with plastic media, and delamination with high pressure water. These methods have many limitations, in that they are labor intensive, pose human health risks, are relatively expensive and pose significant waste disposal problems. However, polymeric coatings are known to contain structural components, such as ester, amide and urea linkages, that can be degraded biologically. The authors are working to develop a stable, enzyme-based, non-toxic paint stripping strategy that will be environmentally safe and cost effective. The specific objectives are to identify and characterize microbial systems capable of degrading polymeric coatings, to develop a quantitative degradation assay and to optimize activity levels for subsequent purification and concentration of the biological products required for rapid degradation of coatings. A water-dispersed colloid of an ester-based polyurethane polymer has been used in solid growth medium to screen about 100 different bacteria for microbial degradation activity. Those with demonstrable activity have been grown in the presence of epoxy-polyamide paint- and polyester polyurethane paint-coated aluminum coupons. The authors have demonstrated delamination under certain conditions and have developed a spectrophotometric method for quantitating degradation activity as a function of dye release.

  5. Gold Coating

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Epner Technology Inc. responded to a need from Goddard Space Flight Center for the ultimate in electroplated reflectivity needed for the Mars Global Surveyor Mars Orbiter Laser Altimeter (MOLA). Made of beryllium, the MOLA mirror was coated by Epner Technology Laser Gold process, specially improved for the project. Improved Laser Gold- coated reflectors have found use in an epitaxial reactor built for a large semiconductor manufacturer as well as the waveguide in Braun-Thermoscan tympanic thermometer and lasing cavities in various surgical instruments.

  6. Commercialization plan for Argonne's lubricious coatings

    SciTech Connect

    Skackson, R.H.

    1991-03-14

    This report summarizes an interview conducted with Dr. David S. Grummon, a specialist in ion beam assisted deposition (IBAD) and coatings at Michigan State University, to define the concept and components of an ion beam assisted deposition (IBAD) system; summarizes findings of a literature search conducted to identify prior and current efforts in developing lubricious coatings; and reports on the market potential for Argonne's IBAD lubricious coating process.

  7. Lifing of Engine Components

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The successful development of advanced aerospace engines depends greatly on the capabilities of high performance materials and structures. Advanced materials, such as nickel based single crystal alloys, metal foam, advanced copper alloys, and ceramics matrix composites, have been engineered to provide higher engine temperature and stress capabilities. Thermal barrier coatings have been developed to improve component durability and fuel efficiency, by reducing the substrate hot wall metal temperature and protecting against oxidation and blanching. However, these coatings are prone to oxidation and delamination failures. In order to implement the use of these materials in advanced engines, it is necessary to understand and model the evolution of damage of the metal substrate as well as the coating under actual engine conditions. The models and the understanding of material behavior are utilized in the development of a life prediction methodology for hot section components. The research activities were focused on determining the stress and strain fields in an engine environment under combined thermo-mechanical loads to develop life prediction methodologies consistent with the observed damage formation of the coating and the substrates.

  8. Biocompatible gradient ceramic coatings for metal implants

    NASA Astrophysics Data System (ADS)

    Sharkany, Josif P.; Sichka, Mikhail J.; Potapchuk, Anatolij M.; Lemko, Ivan S.; Pintye, Josif L.

    2001-08-01

    For the acceleration of the osteointegration processes of the metals implants we deposit on their surface the biokompotible ceramic coatings on the basis of hydroxyapatite. However such coatings have a certain deficiency connected with the absence of the necessary strength characteristics for a such kind of the implant. That's why it actual to create the coatings having beside biological compatibility the necessary strength and springy- elastic properties. We have developed the method of the receiving of the new biocompatible coatings with gradient structure over width on the titanium substrate. The essence of the developed method is in plasma coatings deposition within beforehand given supply of the powder consisting of two components (oxyde aluminum and hydroxyapatite) in the process of the deposition. It's showed that the received gradient coatings are the mixture of the crystals Al2O3 and HA, the concentrations of which change over the width. The topological investigation of the surface and the coating cross-sections was performed from which the chemical composition distribution over width was studied and found the absense of the chemical interaktion between Al2O3 and HA. By regulation of the distribution of the initial components over the coating widths it is possible to set the phase comsposition and crystal sizes in the biocompatible coatings. In the process of etching in the solutions imitating the physiological ones it is found the formation of the pores having dendritic structure. The performed investigations show the possibility of the usage of the developed coatings in medicine particularly in stomatolgoy.

  9. COMPOSITION AND METHOD FOR COATING A CERAMIC BODY

    DOEpatents

    Blanchard, M.K.

    1958-11-01

    A method is presented for protecting a beryllium carbide-graphite body. The method consists in providing a ceramic coating which must contain at least one basic oxide component, such as CaO, at least one amphoteric oxide component, such as Al/sub 2/O/sub 3/, and at least one acidic oxide component, such as SiO/ sub 2/. Various specific formulations for this ceramic coating are given and the coating is applied by conventional ceramic techniques.

  10. Analysis of retrieved hydroxyapatite-coated hip prostheses

    NASA Astrophysics Data System (ADS)

    Gross, K. A.; Walsh, W.; Swarts, E.

    2004-06-01

    Hydroxyapatite (HAp) coatings are used extensively on orthopaedic devices to improve the adhesion of bone to the prosthesis. This approach increases the integrity and longevity of the implanted prosthesis. Four HAp-coated hip components recovered from patients during revision surgery were investigated for bone attachment and coating modification after storage in ethanol or formaldehyde. Orthopedic components displayed preferable bone attachment on microtextured areas and little bone on smoother areas. The coating microstructure differed between three coatings that remained on the prosthesis surface, ranging from completely crystalline coatings made by vacuum plasma spraying to less crystalline coatings manufactured by air plasma spraying. Coating failure for the lower crystallinity coatings was observed by a crack at the interface that was possibly caused by the dissolution of an amorphous phase. While higher crystallinity coatings degraded by coating delamination, the lower crystallinity coating produced loose particulate on the outer coating surface. Coating morphology as observed by scanning electron microscopy (SEM) displayed lamellae fracture, chemical dissolution, osteoclastic resorption, and precipitation in agreement with previously identified in-vitro events. The coating longevity appeared to be extended in those areas subject to lower levels of stress and more bone coverage.

  11. The tribology of PS212 coatings and PM212 composites for the lubrication of titanium 6A1-4V components of a Stirling engine space power system

    NASA Astrophysics Data System (ADS)

    Sliney, Harold E.; Dellacorte, Christopher; Lukaszewicz, Victor

    1995-07-01

    The Stirling space power machine incorporates a linear alternator to generate electrical power. The alternator is a reciprocating device that is driven by a solar or nuclear-powered Stirling engine. The power piston and cylinder are made of titanium 6A1-4V (Ti6-4) alloy, and are designed to be lubricated by a hydrodynamically-generated gas film. Rubbing occurs during starts and stops and there is a possibility of an occasional high speed rub. Since titanium is known to have a severe galling tendency in sliding contacts, a 'backup,' self-lubricating coating on the cylinder and/or the piston is needed. This report describes the results of a research program to study the lubrication of Ti6-4 with the following chromium carbide based materials: plasma-sprayed PS212 coatings and sintered PM212 counterfaces. Program objectives are to achieve adherent coatings on Ti6-4 and to measure the friction and wear characteristics of the following sliding combinations under conditions simulative of the Stirling-driven space power linear alternator: Ti6-4/Ti6-4 baseline, Ti6-4/PS212 coated Ti6-4, and Ps212 coated Ti6-4/PM212

  12. The tribology of PS212 coatings and PM212 composites for the lubrication of titanium 6A1-4V components of a Stirling engine space power system

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.; Dellacorte, Christopher; Lukaszewicz, Victor

    1995-01-01

    The Stirling space power machine incorporates a linear alternator to generate electrical power. The alternator is a reciprocating device that is driven by a solar or nuclear-powered Stirling engine. The power piston and cylinder are made of titanium 6A1-4V (Ti6-4) alloy, and are designed to be lubricated by a hydrodynamically-generated gas film. Rubbing occurs during starts and stops and there is a possibility of an occasional high speed rub. Since titanium is known to have a severe galling tendency in sliding contacts, a 'backup,' self-lubricating coating on the cylinder and/or the piston is needed. This report describes the results of a research program to study the lubrication of Ti6-4 with the following chromium carbide based materials: plasma-sprayed PS212 coatings and sintered PM212 counterfaces. Program objectives are to achieve adherent coatings on Ti6-4 and to measure the friction and wear characteristics of the following sliding combinations under conditions simulative of the Stirling-driven space power linear alternator: Ti6-4/Ti6-4 baseline, Ti6-4/PS212 coated Ti6-4, and Ps212 coated Ti6-4/PM212

  13. The tribology of PS212 coatings and PM212 composites for the lubrication of titanium 6A1-4V components of a Stirling engine space power system

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.; Dellacorte, Christopher; Lukaszewicz, Victor

    1995-01-01

    The Stirling space power machine incorporates a linear alternator to generate electrical power. The alternator is a reciprocating device that is driven by a solar or nuclear-powered Stirling engine. The power piston and cylinder are made of titanium 6A1-4V (Ti6-4) alloy, and are designed to be lubricated by a hydrodynamically-generated gas film. Rubbing occurs during starts and stops and there is a possibility of an occasional high speed rub. Since titanium is known to have a severe galling tendency in sliding contacts, a 'backup,' self-lubricating coating on the cylinder and/or the piston is needed. This report describes the results of a research program to study the lubrication of Ti6-4 with the following chromium carbide based materials: plasma-sprayed PS212 coatings and sintered PM212 counterfaces. Program objectives are to achieve adherent coatings on Ti6-4 and to measure the friction and wear characteristics of the following sliding combinations under conditions simulative of the Stirling-driven space power linear alternator: Ti6-4/Ti6-4 baseline, Ti6-4/PS212 coated Ti6-4, and Ps212 coated Ti6-4/PM212

  14. Nanocomposite Antifriction Coatings for Innovative Tribotechnical Systems

    NASA Astrophysics Data System (ADS)

    Shtanskii, D. V.; Bondarev, A. V.; Kiryukhantsev-Korneev, F. V.; Levashov, E. A.

    2015-11-01

    Different approaches to formation of hard multicomponent coatings with improved tribological characteristics in a wide temperature range are considered. It is shown that deposition of a thin surface layer or introduction of additional structural components into nanocomposite coatings, which play the role of a solid lubricant, lowers substantially the friction factor and increases the wear resistance

  15. Component for thermoelectric generator

    DOEpatents

    Purdy, David L.

    1977-01-01

    In a thermoelectric generator, a component comprises a ceramic insulator, having over limited areas thereof, each area corresponding to a terminal end of thermoelectric wires, a coating of a first metal which adheres to the insulator, and an electrical thermoelectric junction including a second metal which wets said first metal and adheres to said terminal ends but does not wet said insulator, and a cloth composed of electrically insulating threads interlaced with thermoelectric wires.

  16. COATING METHOD

    DOEpatents

    Townsend, R.G.

    1959-08-25

    A method is described for protectively coating beryllium metal by etching the metal in an acid bath, immersing the etched beryllium in a solution of sodium zincate for a brief period of time, immersing the beryllium in concentrated nitric acid, immersing the beryhlium in a second solution of sodium zincate, electroplating a thin layer of copper over the beryllium, and finally electroplating a layer of chromium over the copper layer.

  17. Space Coatings for Industry

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Ball Aerospace developed entirely new space lubrication technologies. A new family of dry lubricants emerged from Apollo, specifically designed for long life in space, together with processes for applying them to spacecraft components in microscopically thin coatings. Lubricants worked successfully on seven Orbiting Solar Observatory flights over the span of a decade and attracted attention to other contractors which became Ball customers. The company has developed several hundred variations of the original OSO technology generally designed to improve the quality and useful life of a wide range of products or improve efficiency of the industrial processes by which such products are manufactured.

  18. Color characterization of coatings with diffraction pigments.

    PubMed

    Ferrero, A; Bernad, B; Campos, J; Perales, E; Velázquez, J L; Martínez-Verdú, F M

    2016-10-01

    Coatings with diffraction pigments present high iridescence, which needs to be characterized in order to describe their appearance. The spectral bidirectional reflectance distribution functions (BRDFs) of six coatings with SpectraFlair diffraction pigments were measured using the robot-arm-based goniospectrophotometer GEFE, designed and developed at CSIC. Principal component analysis has been applied to study the coatings of BRDF data. From data evaluation and based on theoretical considerations, we propose a relevant geometric factor to study the spectral reflectance and color gamut variation of coatings with diffraction pigments. At fixed values of this geometric factor, the spectral BRDF component due to diffraction is almost constant. Commercially available portable goniospectrophotometers, extensively used in several industries (automotive and others), should be provided with more aspecular measurement angles to characterize the complex reflectance of goniochromatic coatings based on diffraction pigments, but they would not require either more than one irradiation angle or additional out-of-plane geometries.

  19. Plasma-sprayed coatings

    SciTech Connect

    Herman, H.

    1988-09-01

    Plasma spraying is one way to apply protective coatings. The hot, high-speed flame of a plasma gun can melt a powder of almost any ceramic or metal and spray it to form a coating for protection against corrosion, wear or high temperature. The technique carries much less risk of degrading the coating and substrate than many other high-temperature processes do, because the gas in the plasma flame is chemically inert and the target can be kept fairly cool. And yet a plasma gun can be only a little more cumbersome than a paint sprayer. Investigators are applying this technique to new materials. The General Electric Company is using vacuum plasma spraying to make freestanding components: intricate aircraft engine parts formed by plasma-spraying a superalloy on a removable substrate. Other workers spray ceramic particles or fibers and metal powder simulatious wrong, stiff composite materials: the ceramic particles dispersed in a matrix of metal. The author and colleagues at the U.S. Naval Research Laboratory have fabricated a thick film of high-temperature superconductor by plasma-spraying the compound in the form of a powder. 7 figs.

  20. Thermal radiative properties: Coatings.

    NASA Technical Reports Server (NTRS)

    Touloukian, Y. S.; Dewitt, D. P.; Hernicz, R. S.

    1972-01-01

    This volume consists, for the most part, of a presentation of numerical data compiled over the years in a most comprehensive manner on coatings for all applications, in particular, thermal control. After a moderately detailed discussion of the theoretical nature of the thermal radiative properties of coatings, together with an overview of predictive procedures and recognized experimental techniques, extensive numerical data on the thermal radiative properties of pigmented, contact, and conversion coatings are presented. These data cover metallic and nonmetallic pigmented coatings, enamels, metallic and nonmetallic contact coatings, antireflection coatings, resin coatings, metallic black coatings, and anodized and oxidized conversion coatings.

  1. Coating Layer Characterization of Laser Deposited AlSi Coating over Laser Weld Bead

    NASA Astrophysics Data System (ADS)

    Gu, Hongping; Van Gelder, Aldo

    Corrosion protection of steel components is an important topic in automotive industry. Laser beam welding makes a narrow weld bead, thus minimizing the damage to the original coating on the steel material. However, the weld bead loses its original coating and is vulnerable to corrosive attack. It was demonstrated in this study that laser beam generated AlSi coating is an effective way to apply a protective coating on the weld bead. Coatings with different thickness and topography have been deposited under different laser power and processing speed. The microstructure of the as-deposited coating and its evolution after heat treatment has been studied. EDS was employed to analyze the distribution of chemical compositions of the laser generated coatings. Several metallic compounds of Al and iron have been identified. It was found that the type of metallic compounds can be influenced by the laser processing parameters.

  2. Eddy Current Assessment of Duplex Metallic Coatings

    NASA Astrophysics Data System (ADS)

    Krzywosz, K. J.

    2004-02-01

    EPRI is involved in a multi-year program with the Department of Energy to test, evaluate, and develop a field-deployable eddy current NDE system for life assessment of blade coatings for advanced gas turbines. The coatings evaluated from these advanced GE engines include CoCrAlY (GT 29) and NiCoCrAlY (GT 33) bond coats followed by top aluminide overlay coatings. These duplex metallic coatings commonly referred to as GT 29+ and GT 33+ coatings, respectively. In general, during cycling and continuous operation at higher operating temperature, coatings fail due to spallation of protective oxide layers, leading to consumption of protective coating by oxidation and to eventual failure of blades. To extend service life of these critical rotating components, an inspection-based condition assessment program has been initiated to help establish more optimum inspection intervals that are not dependent on time-in-service maintenance approach. This paper summarizes the latest results obtained to date using the state-of-the-art frequency-scanning eddy current tester with a built-in three-layer inversion analysis algorithm. Significant progress has been made in assessing and discriminating the duplex metallic coatings as normal, degraded, and/or cracked. In addition, quantitative assessment was conducted by estimating various coating and substrate conductivity values.

  3. In-situ formation of multiphase deposited thermal barrier coatings

    DOEpatents

    Subramanian, Ramesh

    2004-01-13

    A multiphase ceramic thermal barrier coating is provided. The coating is adapted for use in high temperature applications in excess of about 1200.degree. C., for coating superalloy components of a combustion turbine engine. The coating comprises a ceramic single or two oxide base layer disposed on the substrate surface; and a ceramic oxide reaction product material disposed on the base layer, the reaction product comprising the reaction product of the base layer with a ceramic single or two oxide overlay layer.

  4. Thermal conductivity of zirconia thermal barrier coatings

    NASA Technical Reports Server (NTRS)

    Dinwiddie, R. B.; Beecher, S. C.; Nagaraj, B. A.; Moore, C. S.

    1995-01-01

    Thermal barrier coatings (TBC's) applied to the hot gas components of turbine engines lead to enhanced fuel efficiency and component reliability. Understanding the mechanisms which control the thermal transport behavior of the TBC's is of primary importance. Physical vapor deposition (PVD) and plasma spraying (PS) are the two most commonly used coating techniques. These techniques produce coatings with unique microstructures which control their performance and stability. The PS coatings were applied with either standard powder or hollow sphere particles. The hollow sphere particles yielded a lower density and lower thermal conductivity coating. The thermal conductivity of both fully and partially stabilized zirconia, before and after thermal aging, will be compared. The thermal conductivity of the coatings permanently increases upon exposed to high temperatures. These increases are attributed to microstructural changes within the coatings. Sintering of the as-fabricated plasma sprayed lamellar structure is observed by scanning electron microscopy of coatings isothermally heat treated at temperatures greater than 1100 C. During this sintering process the planar porosity between lamella is converted to a series of small spherical pores. The change in pore morphology is the primary reason for the observed increase in thermal conductivity. This increase in thermal conductivity can be modeled using a relationship which depends on both the temperature and time of exposure. Although the PVD coatings are less susceptible to thermal aging effects, preliminary results suggest that they have a higher thermal conductivity than PS coatings, both before and after thermal aging. The increases in thermal conductivity due to thermal aging for partially stabilized plasma sprayed zirconia have been found to be less than for fully stabilized plasma sprayed zirconia coatings. The high temperature thermal diffusivity data indicate that if these coatings reach a temperature above 1100 C

  5. Thermal conductivity of zirconia thermal barrier coatings

    NASA Technical Reports Server (NTRS)

    Dinwiddie, R. B.; Beecher, S. C.; Nagaraj, B. A.; Moore, C. S.

    1995-01-01

    Thermal barrier coatings (TBC's) applied to the hot gas components of turbine engines lead to enhanced fuel efficiency and component reliability. Understanding the mechanisms which control the thermal transport behavior of the TBC's is of primary importance. Physical vapor description (PVD) and plasma spraying (PS) are the two most commonly used coating techniques. These techniques produce coatings with unique microstructures which control their performance and stability. The PS coatings were applied with either standard power or hollow sphere particles. The hollow sphere particles yielded a lower density and lower thermal conductivity coating. The thermal conductivity of both fully and partially stabilized zirconia, before and after thermal aging, will be compared. The thermal conductivity of the coatings permanently increase upon being exposed to high temperatures. These increases are attributed to microstructural changes within the coatings. Sintering of the as fabricated plasma sprayed lamellar structure is observed by scanning electron microscopy of coatings isothermally heat treated at temperatures greater than 1100 C. During this sintering process the planar porosity between lamella is converted to a series of small spherical pores. The change in pore morphology is the primary reason for the observed increase in thermal conductivity. This increase in thermal conductivity can be modeled using a relationship which depends on both the temperature and time of exposure. Although the PVD coatings are less susceptible to thermal aging effects, preliminary results suggest that they have a higher thermal conductivity than PS coatings, both before and after thermal aging. The increases in thermal conductivity due to thermal aging for partially stabilized plasma sprayed zirconia have been found to be less than for fully stabilized plasma sprayed zirconia coatings. The high temperature thermal diffusivity data indicates that if these coatings reach a temperature above

  6. Electrochemical Impedance of Organic Coated Steel; Final Report. Correlation of Impedance Parameters with Long-Term Coating Performance

    DTIC Science & Technology

    1990-09-01

    to be quite useful in monitoring changes to organic polymer coated metals when exposed to a variety of environments [5-9]. The EIS technique normally...e., pure or unfilled) epoxy polyamide polymer coating with organic components per MIL-P-24441 and the neat epoxy system containing a high surface...the blistering rate, the type of coating (filled vs. neat) is seen to be more influential. Whereas the filled polymer coatings exhibited rough- ly a

  7. NICKEL COATED URANIUM ARTICLE

    DOEpatents

    Gray, A.G.

    1958-10-01

    Nickel coatings on uranium and various methods of obtaining such coatings are described. Specifically disclosed are such nickel or nickel alloy layers as barriers between uranium and aluminum- silicon, chromium, or copper coatings.

  8. Corrosion resistant coating

    DOEpatents

    Wrobleski, Debra A.; Benicewicz, Brian C.; Thompson, Karen G.; Bryan, Coleman J.

    1997-01-01

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  9. Corrosion resistant coating

    DOEpatents

    Wrobleski, D.A.; Benicewicz, B.C.; Thompson, K.G.; Bryan, C.J.

    1997-08-19

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  10. Thorium-free interference coatings for infrared applications

    NASA Astrophysics Data System (ADS)

    Laux, Sven; Bernitzki, Helmut; Fasold, Dieter; Gittler, Elvira; Schmidt, Frank; Weyh, Thomas; Wurlitzer, Gottfried

    2005-09-01

    This paper discusses improvements in manufacturing of coated infrared optical components. Such components often have key functions in defence, security or space applications and must withstand severe environmental conditions. Therefore, very durable coatings are desired. As a consequence of its radioactivity the formerly used low refractive index material thorium fluoride is substituted. Examples for beam splitter cubes contacted with novel infrared transparent cement, interference filters, mirrors and AR coatings are presented.

  11. The Chemistry of Coatings.

    ERIC Educational Resources Information Center

    Griffith, James R.

    1981-01-01

    The properties of natural and synthetic polymeric "coatings" are reviewed, including examples and uses of such coatings as cellulose nitrate lacquers (for automobile paints), polyethylene, and others. (JN)

  12. The Chemistry of Coatings.

    ERIC Educational Resources Information Center

    Griffith, James R.

    1981-01-01

    The properties of natural and synthetic polymeric "coatings" are reviewed, including examples and uses of such coatings as cellulose nitrate lacquers (for automobile paints), polyethylene, and others. (JN)

  13. Assessing condition of turbine engine ceramic components through NDE technology.

    SciTech Connect

    Ellingson, W.A.; Sun, J.G.; Deemer, C.; Erdman, S.; Prested, C.

    2002-04-12

    Thermal barrier coatings (TBCs) and environmental barrier coatings (EBCs) are under development for hot-gas path components to allow higher gas-firing temperatures in advanced (high-efficiency, low-emission) gas turbines. Increasing dependence on the reliability of TBC and EBC components has driven the need for nondestructive evaluation (NDE) methods to assess the condition, or ''health status,'' of these coatings. NDE methods based on elastic optical scatter and thermal imaging have been applied to TBC-coated test specimens that were thermally cycled and to EBC-coated SiC/SiC components that were run in 4.5 MW(e) field-test turbines. One primary interest is to develop NDE methods that can predict a prespall condition. Resulting data suggest a correlation between laser scatter data and thermal cycles for TBC-coated specimens, and thermal imaging results have demonstrated prespall detection for an EBC-coated SiC/SiC combustor liner.

  14. The behavior of hydrocolloid coatings on vegetative materials

    PubMed

    Hershko; Nussinovitch

    1998-09-01

    Coating vegetative materials by gelling agents is a process characterized by four different time scales. After wetting and penetration of the vegetative skin by the gum solution, adhesion of the viscous solution to the outer layer (skin) of the coated material is possible. The gelled film (coating) collapses during further drying and adheres to the vegetative tissue. Critical surface tensions of the solid object to be coated, its apparent and real roughness, wettability of the surfaces by the gum solution, the composition and polarity of the films designed to coat the solid, and the surface tension of gum coating solutions are among the critical properties that need to be explored and changed for a successful coating process. The critical surface tensions of garlic peel and gellan and alginate films (coatings) were evaluated by Zisman plots. Garlic skin has a low surface tension compared with those of synthetic films such as polystyrene and polyethylene. A spreading technique was used to determine the surface tension of the dry film and the solid garlic skin. Surface tension was divided into dispersive and polar components. The similarity between the coating solution and the object to be coated in values of dispersive and polar components influences the spreadability of the coating gum solutions. Better compatibility between the coated object and the coating films can be achieved by incorporating surface-active agents within the coating gum solution. From the compatibility requirements detailed above, it can be concluded that tailor-made hydrocolloid coatings for different vegetative materials can only be achieved by further exploring the chemical and physical properties of the coating solutions and the coated objects.

  15. Optical reflector coatings for astronomical applications from EUV to IR

    NASA Astrophysics Data System (ADS)

    Schürmann, Mark; Jobst, Paul Johannes; Yulin, Sergiy; Feigl, Torsten; Heiße, Hanno; Wilbrandt, Steffen; Stenzel, Olaf; Gebhardt, Andreas; Risse, Stefan; Kaiser, Norbert

    2012-09-01

    Optical coatings are an integral part of superior optical components. Astronomical applications (ground- and space-based) place especially high demands on these coatings, not only with regard to their optical performance but also to their mechanical and environmental stability, their thermal properties, and their radiation resistance. This article presents a short overview of several coating solutions developed in recent years at Fraunhofer IOF in order to meet the challenging demands of astronomical applications. The focus is placed on high reflective coatings for different wavelength regions including coatings for the VUV range below 100nm, coatings for the DUV wavelength range above 100nm and VIS/NIR/IR coatings. Further, amorphous silicon layers will be introduced which can be polished to very low roughness values and therefore can act as polishing layer for the manufacture of ultraprecise optical components from metal substrates.

  16. Thermal and Environmental Barrier Coatings for Advanced Propulsion Engine Systems

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Miller, Robert A.

    2004-01-01

    Ceramic thermal and environmental barrier coatings (TEBCs) are used in gas turbine engines to protect engine hot-section components in the harsh combustion environments, and extend component lifetimes. For future high performance engines, the development of advanced ceramic barrier coating systems will allow these coatings to be used to simultaneously increase engine operating temperature and reduce cooling requirements, thereby leading to significant improvements in engine power density and efficiency. In order to meet future engine performance and reliability requirements, the coating systems must be designed with increased high temperature stability, lower thermal conductivity, and improved thermal stress and erosion resistance. In this paper, ceramic coating design and testing considerations will be described for high temperature and high-heat-flux engine applications in hot corrosion and oxidation, erosion, and combustion water vapor environments. Further coating performance and life improvements will be expected by utilizing advanced coating architecture design, composition optimization, and improved processing techniques, in conjunction with modeling and design tools.

  17. Electrocurtain coating process for coating solar mirrors

    SciTech Connect

    Kabagambe, Benjamin; Boyd, Donald W.; Buchanan, Michael J.; Kelly, Patrick; Kutilek, Luke A.; McCamy, James W.; McPheron, Douglas A.; Orosz, Gary R.; Limbacher, Raymond D.

    2013-10-15

    An electrically conductive protective coating or film is provided over the surface of a reflective coating of a solar mirror by flowing or directing a cation containing liquid and an anion containing liquid onto the conductive surface. The cation and the anion containing liquids are spaced from, and preferably out of contact with one another on the surface of the reflective coating as an electric current is moved through the anion containing liquid, the conductive surface between the liquids and the cation containing liquid to coat the conductive surface with the electrically conductive coating.

  18. Multi-layer coatings

    DOEpatents

    Maghsoodi, Sina; Brophy, Brenor L.; Abrams, Ze'ev R.; Gonsalves, Peter R.

    2016-06-28

    Disclosed herein are coating materials and methods for applying a top-layer coating that is durable, abrasion resistant, highly transparent, hydrophobic, low-friction, moisture-sealing, anti-soiling, and self-cleaning to an existing conventional high temperature anti-reflective coating. The top coat imparts superior durability performance and new properties to the under-laying conventional high temperature anti-reflective coating without reducing the anti-reflectiveness of the coating. Methods and data for optimizing the relative thickness of the under-layer high temperature anti-reflective coating and the top-layer thickness for optimizing optical performance are also disclosed.

  19. High-temperature polyimide coating for optical fibres

    SciTech Connect

    Semjonov, S L; Dianov, E M; Sapozhnikov, D A; Erin, D Yu; Zabegaeva, O N; Kushtavkina, I A; Vygodskii, Ya S; Nishchev, K N

    2015-04-30

    We present our first results on the fabrication of new, high-performance polyimide coatings. The key components of the coatings are polyimides containing various cardo and/or fluoroalkylene groups, which allows the coatings to retain their high-temperature stability and facilitates the storage of the starting polymer and the optical fibre coating process owing to the good solubility of such copolymers in many organic solvents. Annealing for 30 s, 1 h and 24 h at temperatures of 430, 350 and 300 °C, respectively, reduces the strength of optical fibres having such coating by no more than 10%. (optical fibres)

  20. Advanced ceramic coating development for industrial/utility gas turbines

    NASA Technical Reports Server (NTRS)

    Vogan, J. W.; Stetson, A. R.

    1982-01-01

    A program was conducted with the objective of developing advanced thermal barrier coating (TBC) systems. Coating application was by plasma spray. Duplex, triplex and graded coatings were tested. Coating systems incorporated both NiCrAly and CoCrAly bond coats. Four ceramic overlays were tested: ZrO2.82O3; CaO.TiO2; 2CaO.SiO2; and MgO.Al2O3. The best overall results were obtained with a CaO.TiO2 coating applied to a NiCrAly bond coat. This coating was less sensitive than the ZrO2.8Y2O3 coating to process variables and part geometry. Testing with fuels contaminated with compounds containing sulfur, phosphorus and alkali metals showed the zirconia coatings were destabilized. The calcium titanate coatings were not affected by these contaminants. However, when fuels were used containing 50 ppm of vanadium and 150 ppm of magnesium, heavy deposits were formed on the test specimens and combustor components that required frequent cleaning of the test rig. During the program Mars engine first-stage turbine blades were coated and installed for an engine cyclic endurance run with the zirconia, calcium titanate, and calcium silicate coatings. Heavy spalling developed with the calcium silicate system. The zirconia and calcium titanate systems survived the full test duration. It was concluded that these two TBC's showed potential for application in gas turbines.

  1. Nanoengineered Additives for Active Coatings

    DTIC Science & Technology

    2007-04-01

    commercial ad bial activ component from the coating, leading to eventual depletion of the film. Small TPU samples were evaluated using a Kirby - Bauer ...7 Table 5. Summary of 24-hr ASTM E 2180 tests with 1 weight-percent additive in PUr (solvent dispersible) based on 6-log loading of...Noveon X-1150). The ASTM E 2180 test is run in triplicate (Note that alternative ro 1° amines) was suspended in dry tetrahydrofuran (THF) (150 mL) in

  2. Chrome - Free Aluminum Coating System

    NASA Technical Reports Server (NTRS)

    Bailey, John H.; Gugel, Jeffrey D.

    2010-01-01

    This slide presentation concerns the program to qualify a chrome free coating for aluminum. The program was required due to findings by OSHA and EPA, that hexavalent chromium, used to mitigate corrosion in aerospace aluminum alloys, poses hazards for personnel. This qualification consisted of over 4,000 tests. The tests revealed that a move away from Cr+6, required a system rather than individual components and that the maximum corrosion protection required pretreatment, primer and topcoat.

  3. Thermal barrier coating life prediction model development

    NASA Technical Reports Server (NTRS)

    Demasi, J. T.; Sheffler, K. D.

    1986-01-01

    The objective of this program is to establish a methodology to predict Thermal Barrier Coating (TBC) life on gas turbine engine components. The approach involves experimental life measurement coupled with analytical modeling of relevant degradation modes. The coating being studied is a flight qualified two layer system, designated PWA 264, consisting of a nominal ten mil layer of seven percent yttria partially stabilized zirconia plasma deposited over a nominal five mil layer of low pressure plasma deposited NiCoCrAlY. Thermal barrier coating degradation modes being investigated include: thermomechanical fatigue, oxidation, erosion, hot corrosion, and foreign object damage.

  4. Protective, Sacrificial Coats On Optical Surfaces

    NASA Technical Reports Server (NTRS)

    Babel, Henry W.; Hasegawa, Mark M.; Jones, Cherie A.

    1994-01-01

    Clear, easily cleaned sacrificial coats of polytetrafluoroethylene, polyurethane, silicone, or other low-outgassing organic films help maintain optical properties of surfaces of radiators, solar panels, and other components. Contamination removed by erosion of coats. Applied by conventional spraying or other techniques. Originally coats intended to protect surfaces of radiators on spacecraft in low orbit around the Earth. On Earth, used to protect optical surfaces against damage during manufacture or protect and facilitate cleaning of optical surfaces particularly delicate or otherwise not cleaned easily.

  5. Protective, Sacrificial Coats On Optical Surfaces

    NASA Technical Reports Server (NTRS)

    Babel, Henry W.; Hasegawa, Mark M.; Jones, Cherie A.

    1994-01-01

    Clear, easily cleaned sacrificial coats of polytetrafluoroethylene, polyurethane, silicone, or other low-outgassing organic films help maintain optical properties of surfaces of radiators, solar panels, and other components. Contamination removed by erosion of coats. Applied by conventional spraying or other techniques. Originally coats intended to protect surfaces of radiators on spacecraft in low orbit around the Earth. On Earth, used to protect optical surfaces against damage during manufacture or protect and facilitate cleaning of optical surfaces particularly delicate or otherwise not cleaned easily.

  6. A simulation technique for predicting thickness of thermal sprayed coatings

    NASA Technical Reports Server (NTRS)

    Goedjen, John G.; Miller, Robert A.; Brindley, William J.; Leissler, George W.

    1995-01-01

    The complexity of many of the components being coated today using the thermal spray process makes the trial and error approach traditionally followed in depositing a uniform coating inadequate, thereby necessitating a more analytical approach to developing robotic trajectories. A two dimensional finite difference simulation model has been developed to predict the thickness of coatings deposited using the thermal spray process. The model couples robotic and component trajectories and thermal spraying parameters to predict coating thickness. Simulations and experimental verification were performed on a rotating disk to evaluate the predictive capabilities of the approach.

  7. Method of applying a bond coating and a thermal barrier coating on a metal substrate, and related articles

    DOEpatents

    Hasz, Wayne Charles; Borom, Marcus Preston

    2002-01-01

    A method for applying at least one bond coating on a surface of a metal-based substrate is described. A foil of the bond coating material is first attached to the substrate surface and then fused thereto, e.g., by brazing. The foil is often initially prepared by thermally spraying the bond coating material onto a removable support sheet, and then detaching the support sheet. Optionally, the foil may also include a thermal barrier coating applied over the bond coating. The substrate can be a turbine engine component.

  8. Positron annihilation behavior in several corrosion protective polymeric coatings

    NASA Astrophysics Data System (ADS)

    Leidheiser, Henry; Szeles, Csaba; Vértes, Attila

    1987-04-01

    Positron annihilation was studied in a vinyl ester and four epoxy coatings on steel. Measurements were made on coatings in equilibrium with air at approximately 50% relative humidity and on coatings immersed in liquid water for 24 h. Three spectral components were identified: a short-lived component associated with annihilation largely in the steel substrate; a medium-lived component associated with annihilation in small voids in the coating; and a long-lived component associated with annihilation of o-positronium in the polymer matrix and within large voids in the polymer and at the polymer/metal interface. An excellent correlation was observed between the effect of water exposure on the annihilation spectra and the protective properties of the coating in an aggressive H 2SO 4 environment. Other correlations between the annihilation spectra and the protective properties were also identified.

  9. Thermal barrier coating evaluation needs

    NASA Technical Reports Server (NTRS)

    Brindley, William J.; Miller, Robert A.

    1990-01-01

    A 0.025 cm (0.010 in) thick thermal barrier coating (TBC) applied to turbine airfoils in a research gas turbine engine provided component temperature reductions of up to 190 C. These impressive temperature reductions can allow increased engine operating temperatures and reduced component cooling to achieve greater engine performance without sacrificing component durability. The significant benefits of TBCs are well established in aircraft gas turbine engine applications and their use is increasing. TBCs are also under intense development for use in the Low Heat Rejection (LHR) diesel engine currently being developed and are under consideration for use in utility and marine gas turbines. However, to fully utilize the benefits of TBCs it is necessary to accurately characterize coating attributes that affect the insulation and coating durability. The purpose there is to discuss areas in which nondestructive evaluation can make significant contributions to the further development and full utilization of TBCs for aircraft gas turbine engines and low heat rejection diesel engines.

  10. Nanoscale Reinforced, Polymer Derived Ceramic Matrix Coatings

    SciTech Connect

    Rajendra Bordia

    2009-07-31

    The goal of this project was to explore and develop a novel class of nanoscale reinforced ceramic coatings for high temperature (600-1000 C) corrosion protection of metallic components in a coal-fired environment. It was focused on developing coatings that are easy to process and low cost. The approach was to use high-yield preceramic polymers loaded with nano-size fillers. The complex interplay of the particles in the polymer, their role in controlling shrinkage and phase evolution during thermal treatment, resulting densification and microstructural evolution, mechanical properties and effectiveness as corrosion protection coatings were investigated. Fe-and Ni-based alloys currently used in coal-fired environments do not possess the requisite corrosion and oxidation resistance for next generation of advanced power systems. One example of this is the power plants that use ultra supercritical steam as the working fluid. The increase in thermal efficiency of the plant and decrease in pollutant emissions are only possible by changing the properties of steam from supercritical to ultra supercritical. However, the conditions, 650 C and 34.5 MPa, are too severe and result in higher rate of corrosion due to higher metal temperatures. Coating the metallic components with ceramics that are resistant to corrosion, oxidation and erosion, is an economical and immediate solution to this problem. Good high temperature corrosion protection ceramic coatings for metallic structures must have a set of properties that are difficult to achieve using established processing techniques. The required properties include ease of coating complex shapes, low processing temperatures, thermal expansion match with metallic structures and good mechanical and chemical properties. Nanoscale reinforced composite coatings in which the matrix is derived from preceramic polymers have the potential to meet these requirements. The research was focused on developing suitable material systems and

  11. Thermal coatings for titanium-aluminum alloys

    NASA Technical Reports Server (NTRS)

    Cunnington, George R.; Clark, Ronald K.; Robinson, John C.

    1993-01-01

    Titanium aluminides and titanium alloys are candidate materials for use in hot structure and heat-shield components of hypersonic vehicles because of their good strength-to-weight characteristics at elevated temperature. However, in order to utilize their maximum temperature capability, they must be coated to resist oxidation and to have a high total remittance. Also, surface catalysis for recombination of dissociated species in the aerodynamic boundary layer must be minimized. Very thin chemical vapor deposition (CVD) coatings are attractive candidates for this application because of durability and very light weight. To demonstrate this concept, coatings of boron-silicon and aluminum-boron-silicon compositions were applied to the titanium-aluminides alpha2 (Ti-14Al-21Nb), super-alpha2 (Ti-14Al-23-Nb-2V), and gamma (Ti-33Al-6Nb-1Ta) and to the titanium alloy beta-21S (Ti-15Mo-3Al-3Nb-0.2Si). Coated specimens of each alloy were subjected to a set of simulated hypersonic vehicle environmental tests to determine their properties of oxidation resistance, surface catalysis, radiative emittance, and thermal shock resistance. Surface catalysis results should be viewed as relative performance only of the several coating-alloy combinations tested under the specific environmental conditions of the LaRC Hypersonic Materials Environmental Test System (HYMETS) arc-plasma-heated hypersonic wind tunnel. Tests were also conducted to evaluate the hydrogen transport properties of the coatings and any effects of the coating processing itself on fatigue life of the base alloys. Results are presented for three types of coatings, which are as follows: (1) a single layer boron silicon coating, (2) a single layer aluminum-boron-silicon coating, and (3) a multilayer coating consisting of an aluminum-boron-silicon sublayer with a boron-silicon outer layer.

  12. Investigation of metallurgical coatings for automotive applications

    NASA Astrophysics Data System (ADS)

    Su, Jun Feng

    Metallurgical coatings have been widely used in the automotive industry from component machining, engine daily running to body decoration due to their high hardness, wear resistance, corrosion resistance and low friction coefficient. With high demands in energy saving, weight reduction and limiting environmental impact, the use of new materials such as light Aluminum/magnesium alloys with high strength-weight ratio for engine block and advanced high-strength steel (AHSS) with better performance in crash energy management for die stamping, are increasing. However, challenges are emerging when these new materials are applied such as the wear of the relative soft light alloys and machining tools for hard AHSS. The protective metallurgical coatings are the best option to profit from these new materials' advantages without altering largely in mass production equipments, machinery, tools and human labor. In this dissertation, a plasma electrolytic oxidation (PEO) coating processing on aluminum alloys was introduced in engine cylinder bores to resist wear and corrosion. The tribological behavior of the PEO coatings under boundary and starve lubrication conditions was studied experimentally and numerically for the first time. Experimental results of the PEO coating demonstrated prominent wear resistance and low friction, taking into account the extreme working conditions. The numerical elastohydrodynamic lubrication (EHL) and asperity contact based tribological study also showed a promising approach on designing low friction and high wear resistant PEO coatings. Other than the fabrication of the new coatings, a novel coating evaluation methodology, namely, inclined impact sliding tester was presented in the second part of this dissertation. This methodology has been developed and applied in testing and analyzing physical vapor deposition (PVD)/ chemical vapor deposition (CVD)/PEO coatings. Failure mechanisms of these common metallurgical hard coatings were systematically

  13. Functionally graded mullite coatings for gas turbines

    NASA Astrophysics Data System (ADS)

    Kulkarni, Tushar

    The next generation of heat exchangers and gas turbines require high performance materials as they need to operate at higher temperatures for higher efficiency. SiC and Si3N4 are promising candidates as they have excellent high temperature properties. However, when used in complex combustion environments found in gas-turbine applications, these materials have two major concerns; namely hot-corrosion and recession. It is well established that environmental barrier coatings (EBC) can be utilized to overcome these limitations. Although chemical vapor deposited (CVD) mullite (3Al2O 3.2SiO2) coatings developed before this study have shown promise in protecting Si-based substrates, there is concern that the silica content within the mullite coating itself might be susceptible to hot-corrosion and recession during long term exposure to corrosive atmospheres containing Na/V salts and water vapor. There is thus strong motivation to substantially reduce or even virtually eliminate the silica component from the surfaces of mullite coatings that are in direct contact with atmospheres containing corrosive oxides and steam. In this study, CVD has been used to deposit mullite coatings with potential promise to protect Si-based ceramics for high temperature applications. The composition of these functionally graded mullite coatings was varied from silica-rich close to the coating/substrate (SiC) interface for coefficient of thermal expansion match to alumina-rich towards the outer surface of the coating. In the process, the highest alumina-rich mullite ever reported has been deposited. The phase transformation and hot-corrosion behavior of the coatings was also investigated in this work. The coatings show immense potential to protect Si-based ceramics. It is expected that these coatings will have very broad impact by enabling gas turbines to operate at higher temperatures leading to improved fuel efficiency and reduced emissions.

  14. Coatings to reduce wood preservative leaching.

    PubMed

    Nejad, Mojgan; Cooper, Paul

    2010-08-15

    The efficiency of semitransparent penetrating stains to reduce leaching of wood preservative components was evaluated. Five commercial wood deck finishes were applied to untreated and chromated copper arsenate (CCA), alkaline copper quat (ACQ), and copper azole (CA) treated wood, and leachates were collected and analyzed during 3 years of natural weathering exposure in Toronto, Canada. All stains evaluated effectively reduced the cumulative leaching of all inorganic preservative components by about 60% on average. Although most coatings showed significant film degradation starting around 12 months, the reduced leaching persisted even after 3 years. This suggests that temporary protection of wood with a coating during the early stages of use resulted in long-term reduction in preservative leaching potential. A two-week screening leaching test was able to predict the long-term leaching performance of different coatings reasonably well. Cured coating glass transition temperature (Tg) and liquid coating viscosity were the most important variables affecting a leaching prediction model. To effectively reduce leaching of preservative components from treated wood, coatings should have Tg low enough to withstand stresses caused by freezing in winter and have adequate viscosity to form a barrier film layer on the wood surface.

  15. Thermal barrier coating life prediction model development

    NASA Technical Reports Server (NTRS)

    Sheffler, K. D.; Demasi, J. T.

    1985-01-01

    A methodology was established to predict thermal barrier coating life in an environment simulative of that experienced by gas turbine airfoils. Specifically, work is being conducted to determine failure modes of thermal barrier coatings in the aircraft engine environment. Analytical studies coupled with appropriate physical and mechanical property determinations are being employed to derive coating life prediction model(s) on the important failure mode(s). An initial review of experimental and flight service components indicates that the predominant mode of TBC failure involves thermomechanical spallation of the ceramic coating layer. This ceramic spallation involves the formation of a dominant crack in the ceramic coating parallel to and closely adjacent to the metal-ceramic interface. Initial results from a laboratory test program designed to study the influence of various driving forces such as temperature, thermal cycle frequency, environment, and coating thickness, on ceramic coating spalling life suggest that bond coat oxidation damage at the metal-ceramic interface contributes significantly to thermomechanical cracking in the ceramic layer. Low cycle rate furnace testing in air and in argon clearly shows a dramatic increase of spalling life in the non-oxidizing environments.

  16. Flow coating apparatus and method of coating

    DOEpatents

    Hanumanthu, Ramasubrahmaniam; Neyman, Patrick; MacDonald, Niles; Brophy, Brenor; Kopczynski, Kevin; Nair, Wood

    2014-03-11

    Disclosed is a flow coating apparatus, comprising a slot that can dispense a coating material in an approximately uniform manner along a distribution blade that increases uniformity by means of surface tension and transfers the uniform flow of coating material onto an inclined substrate such as for example glass, solar panels, windows or part of an electronic display. Also disclosed is a method of flow coating a substrate using the apparatus such that the substrate is positioned correctly relative to the distribution blade, a pre-wetting step is completed where both the blade and substrate are completed wetted with a pre-wet solution prior to dispensing of the coating material onto the distribution blade from the slot and hence onto the substrate. Thereafter the substrate is removed from the distribution blade and allowed to dry, thereby forming a coating.

  17. Anti-reflective and anti-soiling coatings with self-cleaning properties

    SciTech Connect

    Nair, Vinod; Brophy, Brenor L.

    2016-10-04

    Disclosed herein is a coated glass element including a glass component and a coating adhered to the glass component through siloxane linkages, the coating having at least one of an anti-reflective property, a high abrasion resistance property and a hydrophobic property, wherein the coating comprises a dried gel formed from at least one hydrolyzed alkoxysilane-based sol and at least one hydrolyzed organosilane-based sol.

  18. Apparatus for coating powders

    DOEpatents

    Makowiecki, Daniel M.; Kerns, John A.; Alford, Craig S.; McKernan, Mark A.

    2000-01-01

    A process and apparatus for coating small particles and fibers. The process involves agitation by vibrating or tumbling the particles or fibers to promote coating uniformly, removing adsorbed gases and static charges from the particles or fibers by an initial plasma cleaning, and coating the particles or fibers with one or more coatings, a first coating being an adhesion coating, and with subsequent coatings being deposited in-situ to prevent contamination at layer interfaces. The first coating is of an adhesion forming element (i.e. W, Zr, Re, Cr, Ti) of a 100-10,000 .ANG. thickness and the second coating or final coating of a multiple (0.1-10 microns) being Cu or Ag, for example for brazing processes, or other desired materials that defines the new surface related properties of the particles. An essential feature of the coating process is the capability to deposit in-situ without interruption to prevent the formation of a contaminated interface that could adversely affect the coating adhesion. The process may include screening of the material to be coated and either continuous or intermittent vibration to prevent agglomeration of the material to be coated.

  19. Study on Preparation Technologies of Thermal Barrier Coatings

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Wang, Ning; Li, Yang; Wang, Hao; Tang, Jie; Wang, Yunshan

    Thermal barrier coatings (TBCs) is one of the main key technology for the high-pressure turbine blades which are the main components of the high-performance aerospace engines. It offers protection for underline metallic components from corrosion, oxidation and localized melting by insulating the metal from hot gases in the engine core. The properties and lifetime of TBCs are greatly influenced by the preparation technology, which includes plasma spraying (PS), physical vapor deposition (PVD) and laser re-melting (LM). In this paper, three technologies used to prepare the TBCs are reviewed. Resulting features of coating fabricated by each technology are also discussed such as: the porosity, the thermally grown oxide (TGO), the erosion resistance, the thermal shock and so on. Especially, it is pointed out that the performances of gradient coating and nano-coating are better than the traditional coatings. In addition, it is widely accepted that laser can be applied to re-melt the PS coating and even directly clad the gradient coating. In the future, the traditional preparation technology should be improved continually in order to enhance the coating lifetime, enhance the properties of coating and lower the cost of process. Moreover, the researches on gradient-nano-structured coatings preparation are absent and should be done with emphasis since the nano-structure and gradient structure can both benefit the lifetime and properties of coatings.

  20. A study on coating class damage degree by use cycle of gas turbine blade coating

    NASA Astrophysics Data System (ADS)

    Choi, Choul Jun; Kim, Jae Yeol

    2007-07-01

    The component of the hot gas path in gas turbines can survive to very high temperatures because they are protected by ceramic Thermal Barrier Coating(TBC); the failure of such coating can dramatically reduce the component life. A reliable assessment of the Coating integrity and/or an Incipient TBC Damage Detection can help both in optimizing the inspection intervals and in finding the appropriate remedial actions. In this paper the potential of NDT techniques applicable to the metallo/ceramic coating hot parts are discussed in the light of both results obtained on laboratory aged specimens and in field measurements on operated components. An investigation of the NDTs capability to detect damage evolution was performed on thermal-cycled specimens coated with TBC by pulsed thermography. The observation of metallogaphy sections of the thermal cycled specimens allowed to give the right the interpretation to the results of NDT methodology and enlightened its specific characteristics and potentiality. Moreover in field applicability is discussed for each technique. Finally it is shown how an integrated approach of suitable coating evolution models and complimentary NDT techniques can provide an interesting assessment of the damage level of the metallo/ceramic coating of operated rotating blade

  1. Brain components

    MedlinePlus Videos and Cool Tools

    The brain is composed of more than a thousand billion neurons. Specific groups of them, working in concert, provide ... of information. The 3 major components of the brain are the cerebrum, cerebellum, and brain stem. The ...

  2. Mechanical behavior of thermal barrier coatings for gas turbine blades

    NASA Technical Reports Server (NTRS)

    Berndt, C. C.; Phucharoen, W.; Chang, G. C.

    1984-01-01

    Plasma-sprayed thermal barrier coatings (TBCs) will enable turbine components to operate at higher temperatures and lower cooling gas flow rates; thereby improving their efficiency. Future developments are limited by precise knowledge of the material properties and failure mechanisms of the coating system. Details of this nature are needed for realistic modeling of the coating system which will, in turn, promote advancements in coating technology. Complementary experiments and analytical modeling which were undertaken in order to define and measure the important failure processes for plasma-sprayed coatings are presented. The experimental portion includes two different tests which were developed to measure coating properties. These are termed tensile adhesion and acoustic emission tests. The analytical modeling section details a finite element method which was used to calculate the stress distribution in the coating system. Some preliminary results are presented.

  3. Vesicle coats: structure, function, and general principles of assembly.

    PubMed

    Faini, Marco; Beck, Rainer; Wieland, Felix T; Briggs, John A G

    2013-06-01

    The transport of proteins and lipids between distinct cellular compartments is conducted by coated vesicles. These vesicles are formed by the self-assembly of coat proteins on a membrane, leading to collection of the vesicle cargo and membrane bending to form a bud. Scission at the bud neck releases the vesicle. X-ray crystallography and electron microscopy (EM) have recently generated models of isolated coat components and assembled coats. Here, we review these data to present a structural overview of the three main coats: clathrin, COPII, and COPI. The three coats have similar function, common ancestry, and structural similarities, but exhibit fundamental differences in structure and assembly. We describe the implications of structural similarities and differences for understanding the function, assembly principles, and evolution of vesicle coats.

  4. Improved Polyimide Intumescent Coating

    NASA Technical Reports Server (NTRS)

    Salyer, I. O.; Fox, L. B.

    1984-01-01

    New polyimide intumescent coating uses titanium dioxide and glass microballons as nucleating agents to improve foaming characteristics of commercially-available polyimide precursor resin. Used for coating interior surfaces in commercial aircraft.

  5. Experiments with ceramic coatings

    NASA Technical Reports Server (NTRS)

    Lynn, E. K.; Rollins, C. T.

    1968-01-01

    Report describes the procedures and techniques used in the application of a ceramic coating and the evaluation of test parts through observation of the cracks that occur in this coating due to loading.

  6. Corrosion inhibiting organic coatings

    SciTech Connect

    Sasson, E.

    1984-10-16

    A corrosion inhibiting coating comprises a mixture of waxes, petroleum jelly, a hardener and a solvent. In particular, a corrosion inhibiting coating comprises candelilla wax, carnauba wax, microcrystalline waxes, white petrolatum, an oleoresin, lanolin and a solvent.

  7. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S. (Inventor)

    1984-01-01

    A high temperature oxidation resistant, thermal barrier coating system is disclosed for a nickel cobalt, or iron base alloy substrate. An inner metal bond coating contacts the substrate, and a thermal barrier coating covers the bond coating. NiCrAlR, FeCrAlR, and CoCrAlR alloys are satisfactory as bond coating compositions where R=Y or Yb. These alloys contain, by weight, 24.9-36.7% chromium, 5.4-18.5% aluminum, and 0.05 to 1.55% yttrium or 0.05 to 0.53% ytterbium. The coatings containing ytterbium are preferred over those containing yttrium. An outer thermal barrier coating of partial stabilized zirconium oxide (zirconia) which is between 6% and 8%, by weight, of yttrium oxide (yttria) covers the bond coating. Partial stabilization provides a material with superior durability. Partially stabilized zirconia consists of mixtures of cubic, tetragonal, and monoclinic phases.

  8. Electrospark Deposited Coating Technology for Naval Applications (Briefing Charts)

    DTIC Science & Technology

    2002-09-01

    Electrospark Deposited Coating Technology for Naval Applications Denise A. Aylor Naval Surface Warfare Center Carderock Division Marine Corrosion...number. 1. REPORT DATE SEP 2002 2. REPORT TYPE 3. DATES COVERED 00-00-2002 to 00-00-2002 4. TITLE AND SUBTITLE Electrospark Deposited Coating...ANSI Std Z39-18 Objective • Produce good quality coatings using electrospark deposition (ESD) Approach • Identify Navy components for repair

  9. [Biocompatible antibacterial polymer coatings with ciprofloxacin extended release].

    PubMed

    Iarmolenko, M A; Tapal'skiĭ, D B; Rogachev, A V; Rogachev, A A; Kozlova, A I

    2007-01-01

    A procedure for application of thin composite coats based on polymers (polyurethane or polyethylene) and ciprofloxacin in active gaseous phase generated by electron beam dispersion under vacuum was developed. The coats were shown to be highly dispersed systems whose components preserved the initial molecular structure and had antibacterial activity. The composite coats based on polyurethane were more stable to ciprofloxacin leaching in isotonic sodium chloride solution.

  10. Commercialization plan for Argonne`s lubricious coatings

    SciTech Connect

    Skackson, R.H.

    1991-03-14

    This report summarizes an interview conducted with Dr. David S. Grummon, a specialist in ion beam assisted deposition (IBAD) and coatings at Michigan State University, to define the concept and components of an ion beam assisted deposition (IBAD) system; summarizes findings of a literature search conducted to identify prior and current efforts in developing lubricious coatings; and reports on the market potential for Argonne`s IBAD lubricious coating process.

  11. Optical interference coatings for improved luminaire performance. Final report

    SciTech Connect

    Rubins, H.L.

    1981-01-01

    An interior broadbeam HID uplight and an upstream roadway luminaire were developed to demonstrate that optical coated luminaire components can improve the visual effectiveness and energy efficiency of a lighting system. Optical coated reflectors and flat lens covers were very effective in the development of new improved lighting techniques. The coatings reduce reflection and transmission losses, opening the door to new design options for improving lighting performance and saving energy.

  12. Dip Process Thermal-Barrier Coatings for Superalloys.

    DTIC Science & Technology

    1983-03-01

    thermal barrier coatings are needed in aircraft gas turbine engines to increase the thermal efficiency and extend the life of the coated components. In... gas turbine alloys was investigated. This process involves hot dipping alloy substrates in low-melting cerium-nickel or zirconium-nickel eutectics...important conclusion from the work so far is that dense adherent ZrO 2 thermal barrier coatings can be successfully applied on gas turbine alloys by the hot

  13. Evaluation of Coatings for FR-4 Fiberglass Epoxy Composite Probes

    DTIC Science & Technology

    2014-01-01

    FR-4 fiberglass epoxy composite. In an effort to protect the probe from the damaging effects of abrasive components in soil, three commercial epoxy...coatings were evaluated for abrasion resistance. This report focuses on the application and performance properties of coatings applied to the FR-4...fiberglass epoxy composite material. The Standard Test Method for Abrasion Resistance of Organic Coatings by the Taber Abraser (ASTM D4060-10) was used

  14. METHOD FOR TESTING COATINGS

    DOEpatents

    Johns, I.B.; Newton, A.S.

    1958-09-01

    A method is described for detecting pin hole imperfections in coatings on uranium-metal objects. Such coated objects are contacted with a heated atmosphere of gaseous hydrogen and imperfections present in the coatings will allow the uranlum to react with the hydrogen to form uranium hydride. Since uranium hydride is less dense than uranium metal it will swell, causing enlargement of the coating defeot and rendering it visible.

  15. Coating Galvanized Steel

    DTIC Science & Technology

    1989-06-01

    phenolic drying oil products with a zinc dust-zinc oxide pigmentation. Roebuck et al. (Ref 3), state "For instance, coatings subject to saponification ...coating. All three types of TT-P-641 are subject to saponification , since they con- tain drying oils. The General Services Administration (GSA) sells con...penetration " Chemical degradation of coatings, particularly saponification of alkyd coatings in an alkaline environment " Differences in expansion and

  16. Characterization of RSI coating

    NASA Technical Reports Server (NTRS)

    Miller, A. D.; Garofalini, S. H.; Smiser, L. W.; Mueller, J. I.

    1973-01-01

    X-ray diffraction analyses on mullite, silica, and ceramic mullite fiber coating materials to investigate the effects of thermal cycling, show that ceramic mullite fiber coating porosity is little affected by cycling to 1250 C and that material pores are mostly smaller than 15 nm. Some mullite coatings experience a slight increase in crystobalite with somewhat increased porosity. Silica coatings show a marked tendency to precipitate cristobalite with increased porosity and dimensional instability.

  17. Commercial Fastener Coatings Doerken

    DTIC Science & Technology

    2010-06-01

    Phosphating* *partly recommended Dip Spinning Dipping Spraying Spin coating Conveyor oven box oven Inductive drying Pretreatment Coating Preheating...Curing Cooling Application Techniques - Dip Spin Coating Gurtbnd Cross BarTranspo" Band beiCifteiE Vo12one Vent llated Pre .Zone Cros~ Bar T ransrt

  18. Spin coating of electrolytes

    DOEpatents

    Stetter, Joseph R.; Maclay, G. Jordan

    1989-01-01

    Methods for spin coating electrolytic materials onto substrates are disclosed. More particularly, methods for depositing solid coatings of ion-conducting material onto planar substrates and onto electrodes are disclosed. These spin coating methods are employed to fabricate electrochemical sensors for use in measuring, detecting and quantifying gases and liquids.

  19. Ceramic with zircon coating

    NASA Technical Reports Server (NTRS)

    Wang, Hongyu (Inventor)

    2003-01-01

    An article comprises a silicon-containing substrate and a zircon coating. The article can comprise a silicon carbide/silicon (SiC/Si) substrate, a zircon (ZrSiO.sub.4) intermediate coating and an external environmental/thermal barrier coating.

  20. PIT Coating Requirements Analysis

    SciTech Connect

    MINTEER, D.J.

    2000-10-20

    This study identifies the applicable requirements for procurement and installation of a coating intended for tank farm valve and pump pit interior surfaces. These requirements are intended to be incorporated into project specification documents and design media. This study also evaluates previously recommended coatings and identifies requirement-compliant coating products.

  1. Nanocrystalline coatings properties forecasting

    NASA Astrophysics Data System (ADS)

    Eremin, E. N.; Yurov, V. M.; Guchenko, S. A.; Laurynas, V. Ch

    2017-06-01

    The paper considers various properties of nanocrystalline coatings. The methods of determining the surface tension of the deposited coating on the basis of the size dependence of their physical properties. It is shown that predict the mechanical properties of the coatings, their melting point, heat resistance, wear resistance, corrosion resistance, etc. It can be based on a theoretical evaluation of the surface tension.

  2. Nanostructured Carbon Coatings

    DTIC Science & Technology

    2000-01-01

    coatings having a low- friction coefficient for a variety of applications, from heavy-load bearings to nanocoatings for MEMS; protective coating for...tribological coatings having a low-friction coefficient for a variety of applications, from heavy- load bearings to nanocoatings for MEMS. Carbon

  3. Thermal barrier coatings application in diesel engines

    NASA Technical Reports Server (NTRS)

    Fairbanks, J. W.

    1995-01-01

    Commercial use of thermal barrier coatings in diesel engines began in the mid 70's by Dr,. Ingard Kvernes at the Central Institute for Industrial Research in Oslo, Norway. Dr. Kvernes attributed attack on diesel engine valves and piston crowns encountered in marine diesel engines in Norwegian ships as hot-corrosion attributed to a reduced quality of residual fuel. His solution was to coat these components to reduce metal temperature below the threshold of aggressive hot-corrosion and also to provide protection. The Department of Energy has supported thermal barrier coating development for diesel engine applications. In the Clean Diesel - 50 Percent Efficient (CD-50) engine for the year 2000, thermal barrier coatings will be used on piston crowns and possibly other components. The primary purpose of the thermal barrier coatings will be to reduce thermal fatigue as the engine peak cylinder pressure will nearly be doubled. As the coatings result in higher available energy in the exhaust gas, efficiency gains are achieved through use of this energy by turbochargers, turbocompounding or thermoelectric generators.

  4. Barrier Coatings for Refractory Metals and Superalloys

    SciTech Connect

    SM Sabol; BT Randall; JD Edington; CJ Larkin; BJ Close

    2006-02-23

    In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life.

  5. Advanced Low Conductivity Thermal Barrier Coatings: Performance and Future Directions

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    2008-01-01

    Thermal barrier coatings will be more aggressively designed to protect gas turbine engine hot-section components in order to meet future engine higher fuel efficiency and lower emission goals. In this presentation, thermal barrier coating development considerations and performance will be emphasized. Advanced thermal barrier coatings have been developed using a multi-component defect clustering approach, and shown to have improved thermal stability and lower conductivity. The coating systems have been demonstrated for high temperature combustor applications. For thermal barrier coatings designed for turbine airfoil applications, further improved erosion and impact resistance are crucial for engine performance and durability. Erosion resistant thermal barrier coatings are being developed, with a current emphasis on the toughness improvements using a combined rare earth- and transition metal-oxide doping approach. The performance of the toughened thermal barrier coatings has been evaluated in burner rig and laser heat-flux rig simulated engine erosion and thermal gradient environments. The results have shown that the coating composition optimizations can effectively improve the erosion and impact resistance of the coating systems, while maintaining low thermal conductivity and cyclic durability. The erosion, impact and high heat-flux damage mechanisms of the thermal barrier coatings will also be described.

  6. Coating defect evaluation based on stimulated thermography

    NASA Astrophysics Data System (ADS)

    Palumbo, Davide; Tamborrino, Rosanna; Galietti, Umberto

    2017-05-01

    Thermal Barrier Coatings are used to protect the materials from severe temperature and chemical environments. In particular, these materials are used in the engineering fields where high temperatures, corrosive environments and high mechanical stress are required. Defects present between substrate material and coating, as detachments may cause the break of coating and the consequent possibility to exposure the substrate material to the environment conditions. The capability to detect the defect zones with non-destructive techniques could allow the maintenance of coated components with great advantages in terms of costs and prediction of fatigue life. In this work, two different heat sources and two different thermographic techniques have been used to detect the adhesion defects among the base material and the coating. Moreover, an empirical thermographic method has been developed to evaluate the thickness of the thermal coating and to discriminate between an unevenness of the thickness and a defect zone. The study has been conducted on circular steel specimens with simulated adhesion defect and on specimens prepared with different thicknesses of thermal barrier coating.

  7. Bacterial adhesion to bisphosphonate coated hydroxyapatite.

    PubMed

    Ganguli, A; Steward, C; Butler, S L; Philips, G J; Meikle, S T; Lloyd, A W; Grant, M H

    2005-04-01

    Staphylococcus aureus (S. aureus) is commonly associated with microbial infection of orthopaedic implants. Such infections often lead to osteomyelitis, which may result in failure of the implant due to localised bone destruction. Bacterial adhesion and subsequent colonisation of the device may occur as a consequence of contamination during surgery, or by seeding from a distant site through the blood circulation. Coating of the hydroxyapatite (HA) ceramic component of artificial hip joints with the bisphosphonates clodronate (C) and pamidronate (P) has been proposed as a means to minimise osteolysis and thereby prevent loosening of the implant. However, the effect of the bisphosphonate coating on bacterial adhesion to the HA materials must be determined before this approach can be implemented. In this study coated HA materials were incubated with the S. aureus and the number of adherent bacteria determined using the Modified Vortex Device (MVD) method. The number of bacteria adherent to the P coated HA material was significantly greater than that adherent to uncoated HA (60-fold increase) or to the C coated HA (90-fold increase). Therefore, even though earlier studies suggested that P bound to HA may improve osseointegration, the results presented would suggest that the use of this coating may be limited by the potential increased susceptibility of the coated device to infection.

  8. Innovative multilayer coated optics for Solar Physics

    NASA Astrophysics Data System (ADS)

    Meltchakov, Evgueni; Auchere, Frederic; Delmotte, Franck; De Rossi, Sebastien; Mercier, Raymond; Zhang, Xueyan

    Development of multilayer coated optics with specific spectral characteristics and enhanced temporal, thermal and radiation stability requires an innovative approach to the design of reflecting multilayers and optimization of the coating process. Here we report on the progress in design, calculations and fabrication of reflecting multilayer coatings for solar imaging in the extreme ultra-violet (EUV) range. We will present recent results of characterization of new tri-component periodic multilayer structures containing aluminum as a low absorbing material within the spectral range from 17 to 40 nm. The EUV peak reflectance of these coatings (for instance, the Al/Mo/SiC multilayers) reaches 56% at 17.4 nm and 42% at 30 nm, highest reported up to now for these wavelengths. We have studied the temporal and thermal stability of structural and optical parameters of Al-based multilayer coatings as well as the resistivity of the coatings to high-energy and high-dose proton irradiation. A special attention will be drawn to specific bi-periodic systems with enhanced selectivity, which possess two efficient reflection bands and attenuate some unwanted emission lines in the EUV range. Experimental results show that such multilayer coatings are good candidates for the EUV imaging telescopes of Solar Orbiter and future solar missions.

  9. Coatings Extend Life of Engines and Infrastructure

    NASA Technical Reports Server (NTRS)

    2010-01-01

    MesoCoat Inc., of Euclid, Ohio, collaborated with Glenn Research Center to provide thermal barrier coating (TBC) technology, developed by Glenn researcher Dongming Zhu, to enhance the lifespan and performance of engines in U.S. Air Force legacy aircraft. The TBC reduces thermal stresses on engine parts, increasing component life by 50 percent. MesoCoat is also producing metal cladding technology that may soon provide similar life-lengthening benefits for the Nation's infrastructure. Through a Space Act Agreement with Glenn, the company employs the Center's high-density infrared arc lamp system to bond its cladding materials for demonstration prototypes; the coating technology can prevent corrosion on metal beams, pipes, and rebar for up to 100 years.

  10. Broadband antireflection coatings for multifunctional avionic displays

    NASA Astrophysics Data System (ADS)

    Kumari, Neelam; Kumar, Mukesh; Rao, P. K.; Karar, Vinod; Sharma, Amit Lochan

    2015-06-01

    Broadband Multilayer Antireflection (AR) coatings markedly improve the transmission efficiency of any optical component such as lens, prism, beam-splitter, beam combiner or a window. By reducing surface reflections over a wide wavelength range, broadband antireflection coatings improve transmission and enhance contrast which is desired in avionic displays. The broadband antireflection coating consisting of MgF2, ZrO2 and Al2O3 were designed to cover the whole visible spectrum and fabricated on optical grade glass substrate. The optical characterization of these coatings indicates reduction of the reflection to 2.28% as compared to 8.5 % at 545 nm (i.e. design wavelength of most avionic displays) for bare substrate making them useful in optical displays for avionic applications.

  11. Paper-Thin Coating Offers Maximum Protection

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Wessex Incorporated has recently taken a technology that was originally developed for NASA as a protective coating for ceramic materials used in heatshields for space vehicles, and modified it for use in applications such as building materials, machinery, and transportation. The technology, developed at NASA Ames Research Center as a protective coating for flexible ceramic composites (PCC), is environmentally safe, water-based, and contains no solvents. Many other flame-retardant materials contain petroleum-based components, which can produce toxic smoke under flame. Wessex versions of PCC can be used to shield ceramics, wood, plasterboard, steel, plastics, fiberglass, and other materials from catastrophic fires. They are extraordinarily tough and exhibit excellent resistance to thermal shock, vibration, abrasion, and mechanical damage. One thin layer of coating provides necessary protection and allows for flexibility while avoiding excessive weight disadvantages. The coating essentially reduces the likelihood of the underlying material becoming so hot that it combusts and thus inhibits the "flashover" phenomenon from occurring.

  12. Atomically Bonded Transparent Superhydrophobic Coatings

    SciTech Connect

    Aytug, Tolga

    2015-08-01

    Maintaining clarity and avoiding the accumulation of water and dirt on optically transparent surfaces such as US military vehicle windshields, viewports, periscope optical head windows, and electronic equipment cover glasses are critical to providing a high level of visibility, improved survivability, and much-needed safety for warfighters in the field. Through a combination of physical vapor deposition techniques and the exploitation of metastable phase separation in low-alkali borosilicate, a novel technology was developed for the fabrication of optically transparent, porous nanostructured silica thin film coatings that are strongly bonded to glass platforms. The nanotextured films, initially structurally superhydrophilic, exhibit superior superhydrophobicity, hence antisoiling ability, following a simple but robust modification in surface chemistry. The surfaces yield water droplet contact angles as high as 172°. Moreover, the nanostructured nature of these coatings provides increased light scattering in the UV regime and reduced reflectivity (i.e., enhanced transmission) over a broad range of the visible spectrum. In addition to these functionalities, the coatings exhibit superior mechanical resistance to abrasion and are thermally stable to temperatures approaching 500°C. The overall process technology relies on industry standard equipment and inherently scalable manufacturing processes and demands only nontoxic, naturally abundant, and inexpensive base materials. Such coatings, applied to the optical components of current and future combat equipment and military vehicles will provide a significant strategic advantage for warfighters. The inherent self-cleaning properties of such superhydrophobic coatings will also mitigate biofouling of optical windows exposed to high-humidity conditions and can help decrease repair/replacement costs, reduce maintenance, and increase readiness by limiting equipment downtime.

  13. Enhancing thermal barrier coatings performance through reinforcement of ceramic topcoat

    NASA Astrophysics Data System (ADS)

    Bogdanovich, V. I.; Giorbelidze, M. G.

    2016-11-01

    This paper studies structure of thermal barrier coatings applied to hot gas path components in gas turbine engines and produced in a number of ways, and its impact on performance. Methods of structural reinforcement for ceramic topcoat in thermal barrier coatings are considered.

  14. Engineered PlyCB as Novel Implant Coating for Osseointegration

    DTIC Science & Technology

    2011-09-01

    for visualization by fluorescent microscopy in later aims. Next, we tested the binding of mutants to hydroxyapatite (HA) under various salt, pH...osteoblast, hydroxyapatite , titanium implant, bioactive coating 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF...or shortened lifespan under physiological loads. Coatings such as hydroxyapatite , the mineral component of bone, are often used to promote

  15. EMISSIONS FROM COATINGS USED IN THE AUTO REFINISHING INDUSTRY

    EPA Science Inventory

    The report presents results of EPA Methods 24 and 311 analyses of the volatile organic compound (VOC) content of selected auto refinishing coatings and their components that are sold by the five major auto coating manufacturers. These analyses were undertaken to determine the acc...

  16. Coated silicon comprising material for protection against environmental corrosion

    NASA Technical Reports Server (NTRS)

    Hazel, Brian Thomas (Inventor)

    2009-01-01

    In accordance with an embodiment of the invention, an article is disclosed. The article comprises a gas turbine engine component substrate comprising a silicon material; and an environmental barrier coating overlying the substrate, wherein the environmental barrier coating comprises cerium oxide, and the cerium oxide reduces formation of silicate glass on the substrate upon exposure to corrodant sulfates.

  17. EMISSIONS FROM COATINGS USED IN THE AUTO REFINISHING INDUSTRY

    EPA Science Inventory

    The report presents results of EPA Methods 24 and 311 analyses of the volatile organic compound (VOC) content of selected auto refinishing coatings and their components that are sold by the five major auto coating manufacturers. These analyses were undertaken to determine the acc...

  18. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Liquid, spray on elastomeric polyurethanes are selected and investigated as best candidates for aircraft external protective coatings. Flight tests are conducted to measure drag effects of these coatings compared to paints and a bare metal surface. The durability of two elastometric polyurethanes are assessed in airline flight service evaluations. Laboratory tests are performed to determine corrosion protection properties, compatibility with aircraft thermal anti-icing systems, the effect of coating thickness on erosion durability, and the erosion characteristics of composite leading edges-bare and coated. A cost and benefits assessment is made to determine the economic value of various coating configurations to the airlines.

  19. Antibacterial polymer coatings.

    SciTech Connect

    Wilson, Mollye C.; Allen, Ashley N.; Barnhart, Meghan; Tucker, Mark David; Hibbs, Michael R.

    2009-09-01

    A series of poly(sulfone)s with quaternary ammonium groups and another series with aldehyde groups are synthesized and tested for biocidal activity against vegetative bacteria and spores, respectively. The polymers are sprayed onto substrates as coatings which are then exposed to aqueous suspensions of organisms. The coatings are inherently biocidal and do not release any agents into the environment. The coatings adhere well to both glass and CARC-coated coupons and they exhibit significant biotoxicity. The most effective quaternary ammonium polymers kills 99.9% of both gram negative and gram positive bacteria and the best aldehyde coating kills 81% of the spores on its surface.

  20. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S.; Leibert, C. H. (Inventor)

    1977-01-01

    A coating system which contains a bond coating and a thermal barrier coating is applied to metal surfaces such as turbine blades and provides both low thermal conductivity and improved adherence when exposed to high temperature gases or liquids. The bond coating contains NiCrAlY and the thermal barrier coating contains a reflective oxide. The reflective oxides ZrO2-Y2O3 and ZrO2-MgO have demonstrated significant utility in high temperature turbine applications.

  1. Lubricant Coating Process

    NASA Technical Reports Server (NTRS)

    1989-01-01

    "Peen Plating," a NASA developed process for applying molybdenum disulfide, is the key element of Techniblast Co.'s SURFGUARD process for applying high strength solid lubricants. The process requires two machines -- one for cleaning and one for coating. The cleaning step allows the coating to be bonded directly to the substrate to provide a better "anchor." The coating machine applies a half a micron thick coating. Then, a blast gun, using various pressures to vary peening intensities for different applications, fires high velocity "media" -- peening hammers -- ranging from plastic pellets to steel shot. Techniblast was assisted by Rural Enterprises, Inc. Coating service can be performed at either Techniblast's or a customer's facility.

  2. Metallic coating of microspheres

    SciTech Connect

    Meyer, S.F.

    1980-08-15

    Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates.

  3. Battery component

    SciTech Connect

    Goebel, F.; Batson, D.C.; Miserendino, A.J.; Boyle, G.

    1988-03-15

    A mechanical component for reserve type electrochemical batteries having cylindrical porous members is described comprising a disc having: (i) circular grooves in one flat side for accepting the porous members; and (ii) at least one radial channel in the opposite flat side in fluid communication with the grooves.

  4. Method for vacuum pressing electrochemical cell components

    NASA Technical Reports Server (NTRS)

    Andrews, Craig C. (Inventor); Murphy, Oliver J. (Inventor)

    2004-01-01

    Assembling electrochemical cell components using a bonding agent comprising aligning components of the electrochemical cell, applying a bonding agent between the components to bond the components together, placing the components within a container that is essentially a pliable bag, and drawing a vacuum within the bag, wherein the bag conforms to the shape of the components from the pressure outside the bag, thereby holding the components securely in place. The vacuum is passively maintained until the adhesive has cured and the components are securely bonded. The bonding agent used to bond the components of the electrochemical cell may be distributed to the bonding surface from distribution channels in the components. To prevent contamination with bonding agent, some areas may be treated to produce regions of preferred adhesive distribution and protected regions. Treatments may include polishing, etching, coating and providing protective grooves between the bonding surfaces and the protected regions.

  5. Vacuum plasma spray coating

    NASA Technical Reports Server (NTRS)

    Holmes, Richard R.; Mckechnie, Timothy N.

    1989-01-01

    Currently, protective plasma spray coatings are applied to space shuttle main engine turbine blades of high-performance nickel alloys by an air plasma spray process. Originally, a ceramic coating of yttria-stabilized zirconia (ZrO2.12Y2O3) was applied for thermal protection, but was removed because of severe spalling. In vacuum plasma spray coating, plasma coatings of nickel-chromium-aluminum-yttrium (NiCrAlY) are applied in a reduced atmosphere of argon/helium. These enhanced coatings showed no spalling after 40 MSFC burner rig thermal shock cycles between 927 C (1700 F) and -253 C (-423 F), while current coatings spalled during 5 to 25 test cycles. Subsequently, a process was developed for applying a durable thermal barrier coating of ZrO2.8Y2O3 to the turbine blades of first-stage high-pressure fuel turbopumps utilizing the enhanced NiCrAlY bond-coating process. NiCrAlY bond coating is applied first, with ZrO2.8Y2O3 added sequentially in increasing amounts until a thermal barrier coating is obtained. The enchanced thermal barrier coating has successfully passed 40 burner rig thermal shock cycles.

  6. Coatings for directional eutectics

    NASA Technical Reports Server (NTRS)

    Rairden, J. R.; Jackson, M. R.

    1976-01-01

    Significant advances have been made in the development of an environmentally stable coating for a very high strength, directionally solidified eutectic alloy designated NiTaC-13. Three duplex (two-layer) coatings survived 3,000 hours on a cyclic oxidation test (1,100 C to 90 C). These coatings were fabricated by first depositing a layer of NiCrAl(Y) by vacuum evaporation from an electron beam heated source, followed by depositing an aluminizing overlayer. The alloy after exposure with these coatings was denuded of carbide fibers at the substrate/coating interface. It was demonstrated that TaC fiber denudation can be greatly retarded by applying a carbon-bearing coating. The coating was applied by thermal spraying followed by aluminization. Specimens coated with NiCrAlCY+Al survived over 2,000 hours in the cyclic oxidation test with essentially no TaC denudation. Coating ductility was studied for coated and heat-treated bars, and stress rupture life at 871 C and 1,100 C was determined for coated and cycled bars.

  7. Coated Aerogel Beads

    NASA Technical Reports Server (NTRS)

    Littman, Howard (Inventor); Plawsky, Joel L. (Inventor); Paccione, John D. (Inventor)

    2014-01-01

    Methods and apparatus for coating particulate material are provided. The apparatus includes a vessel having a top and a bottom, a vertically extending conduit having an inlet in the vessel and an outlet outside of the vessel, a first fluid inlet in the bottom of the vessel for introducing a transfer fluid, a second fluid inlet in the bottom of the vessel for introducing a coating fluid, and a fluid outlet from the vessel. The method includes steps of agitating a material, contacting the material with a coating material, and drying the coating material to produce a coated material. The invention may be adapted to coat aerogel beads, among other materials. A coated aerogel bead and an aerogel-based insulation material are also disclosed.

  8. Development and Testing of Ceramic Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Choi, Sung R.; Miller, Robert A.

    2004-01-01

    Ceramic thermal barrier coatings will play an increasingly important role in future gas turbine engines because of their ability to effectively protect the engine components and further raise engine temperatures. Durability of the coating systems remains a critical issue with the ever-increasing temperature requirements. Thermal conductivity increase and coating degradation due to sintering and phase changes are known to be detrimental to coating performance. There is a need to characterize the coating behavior and temperature limits, in order to potentially take full advantage of the current coating capability, and also accurately assess the benefit gained from advanced coating development. In this study, thermal conductivity behavior and cyclic durability of plasma-sprayed ZrO2-8wt%Y2O3 thermal barrier coatings were evaluated under laser heat-flux simulated high temperature, large thermal gradient and thermal cycling conditions. The coating degradation and failure processes were assessed by real-time monitoring of the coating thermal conductivity under the test conditions. The ceramic coating crack propagation driving forces and resulting failure modes will be discussed in light of high temperature mechanical fatigue and fracture testing results.

  9. Porosity and wear resistance of flame sprayed tungsten carbide coatings

    NASA Astrophysics Data System (ADS)

    Winarto, Winarto; Sofyan, Nofrijon; Rooscote, Didi

    2017-06-01

    Thermal-sprayed coatings offer practical and economical solutions for corrosion and wear protection of components or tools. To improve the coating properties, heat treatment such as preheat is applied. The selection of coating and substrate materials is a key factor in improving the quality of the coating morphology after the heat treatment. This paper presents the experimental results regarding the effect of preheat temperatures, i.e. 200°C, 300°C and 400°C, on porosity and wear resistance of tungsten carbide (WC) coating sprayed by flame thermal coating. The powders and coatings morphology were analyzed by a Field Emission Scanning Electron Microscope equipped with Energy Dispersive Spectrometry (FE-SEM/EDS), whereas the phase identification was performed by X-Ray diffraction technique (XRD). In order to evaluate the quality of the flame spray obtained coatings, the porosity, micro-hardness and wear rate of the specimens was determined. The results showed that WC coating gives a higher surface hardness from 1391 HVN up to 1541 HVN compared to that of the non-coating. Moreover, the wear rate increased from 0.072 mm3/min. to 0.082 mm3/min. when preheat temperature was increased. Preheat on H13 steel substrate can reduce the percentage of porosity level from 10.24 % to 3.94% on the thermal spray coatings.

  10. Diffusion Barriers to Increase the Oxidative Life of Overlay Coatings

    NASA Technical Reports Server (NTRS)

    Nesbitt, James A.; Lei, Jih-Fen

    1999-01-01

    Currently, most blades and vanes in the hottest section of aero gas turbine engines require some type of coating for oxidation protection. Newly developed single crystal superalloys have the mechanical potential to operate at increasingly higher component temperatures. However, at these elevated temperatures, coating/substrate interdiffusion can shorten the protective life of the coating. Diffusion barriers between overlay coatings and substrates are being examined to extend the protective life of the coating. A previously- developed finite-difference diffusion model has been modified to predict the oxidative life enhancement due to use of a diffusion barrier. The original diffusion model, designated COSIM, simulates Al diffusion in the coating to the growing oxide scale as well as Al diffusion into the substrate. The COSIM model incorporates an oxide growth and spalling model to provide the rate of Al consumption during cyclic oxidation. Coating failure is predicted when the Al concentration at the coating surface drops to a defined critical level. The modified COSIM model predicts the oxidative life of an overlay coating when a diffusion barrier is present eliminating diffusion of Al from the coating into the substrate. Both the original and the modified diffusion models have been used to predict the effectiveness of a diffusion barrier in extending the protective life of a NiCrAl overlay coating undergoing cyclic oxidation at 1100 C.

  11. Combustion chemical vapor desposited coatings for thermal barrier coating systems

    SciTech Connect

    Hampikian, J.M.; Carter, W.B.

    1995-10-01

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings.

  12. Anticorrosive organic/inorganic hybrid coatings

    NASA Astrophysics Data System (ADS)

    Gao, Tongzhai

    Organic/inorganic hybrid coating system was developed for anticorrosion applications using polyurea, polyurethane or epoxide as the organic phase and polysiloxane, formed by sol-gel process, as the inorganic phase. Polyurea/polysiloxane hybrid coatings were formulated and moisture cured using HDI isocyanurate, alkoxysilane-functionalized HDI isocyanurate, and tetraethyl orthosilicate (TEOS) oligomers. Two urethanes were prepared using the same components as abovementioned in addition to the oligoesters derived from either cyclohexane diacids (CHDA) and 2-butyl-2-ethyl-1,3-propanediol (BEPD) or adipic acid (AA), isophthalic acid (IPA), 1,6-hexanediol (HD), and trimethylol propane (TMP). Accelerated weathering and outdoor exposure were performed to study the weatherability of the polyurethane/polysiloxane hybrid coating system. FTIR and solid-state 13C NMR revealed that the degradation of the hybrid coatings occurred at the urethane and ester functionalities of the organic phase. DMA and DSC analyses showed the glass transition temperature increased and broadened after weathering. SEM was employed to observe the change of morphology of the hybrid coatings and correlated with the gloss variation after weathering. Rutile TiO2 was formulated into polyurethane/polysiloxane hybrid coatings in order to investigate the effect of pigmentation on the coating properties and the sol-gel precursor. Chemical interaction between the TiO2 and the sol-gel precursor was investigated using solid-state 29Si NMR and XPS. The morphology, mechanical, viscoelastic, thermal properties of the pigmented coatings were evaluated as a function of pigmentation volume concentration (PVC). Using AFM and SEM, the pigment were observed to be well dispersed in the polymer matrix. The thermal stability, the tensile modulus and strength of the coatings were enhanced with increasing PVC, whereas the pull-off adhesion and flexibility were reduced with increasing PVC. Finally, the pigmented coatings were

  13. Development of improved potting and conformal coating compounds

    NASA Technical Reports Server (NTRS)

    Webster, J. A.

    1969-01-01

    Improved organic potting and conformal coating materials protect fragile electronic components and circuitry from mechanical shock and vibration, moisture, and corrosion. These materials meet specifications covering resistance to cycling, radiation, flammability, and sterilizing agents for certain space applications.

  14. Bond strength and stress measurements in thermal barrier coatings

    SciTech Connect

    Gell, M.; Jordan, E.

    1995-10-01

    Thermal barrier coatings have been used extensively in aircraft gas turbines for more than 15 years to insulate combustors and turbine vanes from the hot gas stream. Plasma sprayed thermal barrier coatings (TBCs) provide metal temperature reductions as much as 300{degrees}F, with improvements in durability of two times or more being achieved. The introduction of TBCs deposited by electron beam physical vapor deposition (EB-PVD) processes in the last five years has provided a major improvement in durability and also enabled TBCs to be applied to turbine blades for improved engine performance. To meet the aggressive Advanced Turbine Systems goals for efficiency, durability and the environment, it will be necessary to employ thermal barrier coatings on turbine airfoils and other hot section components. For The successful application of TBCs to ATS engines with 2600{degrees}F turbine inlet temperatures and required component lives 10 times greater than those for aircraft gas turbine engines, it is necessary to develop quantitative assessment techniques for TBC coating integrity with time and cycles in ATS engines. Thermal barrier coatings in production today consist of a metallic bond coat, such as an MCrAlY overlay coating or a platinum aluminide (Pt-Al) diffusion coating. During heat treatment, both these coatings form a thin, tightly adherent alumina (Al{sub 2}O{sub 3}) film. Failure of TBC coatings in engine service occurs by spallation of the ceramic coating at or near the bond coat to alumina or the alumina to zirconia bonds. Thus, it is the initial strength of these bonds and the stresses at the bond plane, and their changes with engine exposure, that determines coating durability. The purpose of this program is to provide, for the first time, a quantitative assessment of TBC bond strength and bond plane stresses as a function of engine time and cycles.

  15. Hyperfrequency components

    NASA Astrophysics Data System (ADS)

    1994-09-01

    The document has a collection of 19 papers (11 on technologies, 8 on applications) by 26 authors and coauthors. Technological topics include: evolution from conventional HEMT's double heterojunction and planar types of pseudomorphic HEMT's; MMIC R&D and production aspects for very-low-noise, low-power, and very-low-noise, high-power applications; hyperfrequency CAD tools; parametric measurements of hyperfrequency components on plug-in cards for design and in-process testing uses; design of Class B power amplifiers and millimetric-wave, bigrid-transistor mixers, exemplifying combined use of three major types of physical simulation in electrical modeling of microwave components; FET's for power amplification at up to 110 GHz; production, characterization, and nonlinear applications of resonant tunnel diodes. Applications topics include: development of active modules for major European programs; tubes versus solid-state components in hyperfrequency applications; status and potentialities of national and international cooperative R&D on MMIC's and CAD of hyperfrequency circuitry; attainable performance levels in multifunction MMIC applications; state of the art relative of MESFET power amplifiers (Bands S, C, X, Ku); creating a hyperfrequency functions library, of parametrizable reference cells or macrocells; and design of a single-stage, low-noise, band-W amplifier toward development of a three-stage amplifier.

  16. Component separations.

    PubMed

    Heller, Lior; McNichols, Colton H; Ramirez, Oscar M

    2012-02-01

    Component separation is a technique used to provide adequate coverage for midline abdominal wall defects such as a large ventral hernia. This surgical technique is based on subcutaneous lateral dissection, fasciotomy lateral to the rectus abdominis muscle, and dissection on the plane between external and internal oblique muscles with medial advancement of the block that includes the rectus muscle and its fascia. This release allows for medial advancement of the fascia and closure of up to 20-cm wide defects in the midline area. Since its original description, components separation technique underwent multiple modifications with the ultimate goal to decrease the morbidity associated with the traditional procedure. The extensive subcutaneous lateral dissection had been associated with ischemia of the midline skin edges, wound dehiscence, infection, and seroma. Although the current trend is to proceed with minimally invasive component separation and to reinforce the fascia with mesh, the basic principles of the techniques as described by Ramirez et al in 1990 have not changed over the years. Surgeons who deal with the management of abdominal wall defects are highly encouraged to include this technique in their collection of treatment options.

  17. Ceramic thermal barrier coatings for commercial gas turbine engines

    NASA Technical Reports Server (NTRS)

    Meier, Susan Manning; Gupta, Dinesh K.; Sheffler, Keith D.

    1991-01-01

    The paper provides an overview of the short history, current status, and future prospects of ceramic thermal barrier coatings for gas turbine engines. Particular attention is given to plasma-sprayed and electron beam-physical vapor deposited yttria-stabilized (7 wt pct Y2O3) zirconia systems. Recent advances include improvements in the spallation life of thermal barrier coatings, improved bond coat composition and spraying techniques, and improved component design. The discussion also covers field experience, life prediction modeling, and future directions in ceramic coatings in relation to gas turbine engine design.

  18. Chemical Vapor Deposition of Turbine Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Haven, Victor E.

    1999-01-01

    Ceramic thermal barrier coatings extend the operating temperature range of actively cooled gas turbine components, therefore increasing thermal efficiency. Performance and lifetime of existing ceram ic coatings are limited by spallation during heating and cooling cycles. Spallation of the ceramic is a function of its microstructure, which is determined by the deposition method. This research is investigating metalorganic chemical vapor deposition (MOCVD) of yttria stabilized zirconia to improve performance and reduce costs relative to electron beam physical vapor deposition. Coatings are deposited in an induction-heated, low-pressure reactor at 10 microns per hour. The coating's composition, structure, and response to the turbine environment will be characterized.

  19. The Lattice and Thermal Radiation Conductivity of Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Spuckler, Charles M.

    2008-01-01

    The lattice and radiation conductivity of thermal barrier coatings was evaluated using a laser heat flux approach. A diffusion model has been established to correlate the apparent thermal conductivity of the coating to the lattice and radiation conductivity. The radiation conductivity component can be expressed as a function of temperature and the scattering and absorption properties of the coating material. High temperature scattering and absorption of the coating systems can also be derived based on the testing results using the modeling approach. The model prediction is found to have good agreement with experimental observations.

  20. Probability of detection of defects in coatings with electronic shearography

    NASA Technical Reports Server (NTRS)

    Russell, S. S.; Lansing, M. D.; Horton, C. M.; Gnacek, W. J.

    1995-01-01

    The goal of this research was to utilize statistical methods to evaluate the probability of detection (POD) of defects in coatings using electronic shearography. The coating system utilized in the POD studies was to be the paint system currently utilized on the external casings of the NASA space transportation system reusable solid rocket motor boosters. The population of samples was to be large enough to determine the minimum defect size for 90-percent POD of 95-percent confidence POD on these coatings. Also, the best methods to excite coatings on aerospace components to induce deformations for measurement by electronic shearography were to be determined.

  1. Probability of detection of defects in coatings with electronic shearography

    NASA Technical Reports Server (NTRS)

    Maddux, Gary A.; Horton, Charles M.; Lansing, Matthew D.; Gnacek, William J.; Newton, Patrick L.

    1994-01-01

    The goal of this research was to utilize statistical methods to evaluate the probability of detection (POD) of defects in coatings using electronic shearography. The coating system utilized in the POD studies was to be the paint system currently utilized on the external casings of the NASA Space Transportation System (STS) Revised Solid Rocket Motor (RSRM) boosters. The population of samples was to be large enough to determine the minimum defect size for 90 percent probability of detection of 95 percent confidence POD on these coatings. Also, the best methods to excite coatings on aerospace components to induce deformations for measurement by electronic shearography were to be determined.

  2. Alternating-Composition Layered Ceramic Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Miller, Robert A.; Zhu, Dongming

    2008-01-01

    Ceramic thermal and environmental barrier coatings (T/EBCs) that contain multiple layers of alternating chemical composition have been developed as improved means of protecting underlying components of gas-turbine and other heat engines against both corrosive combustion gases and high temperatures.

  3. Tailored coatings for hardfacing

    SciTech Connect

    Dustoor, M.R.; Moskowitz, L.N.

    1984-01-01

    An update on Conforma Clad coatings, first presented at the 1982 National Powder Metallurgy Conference in Montreal, Canada, is presented. The major advantage is the ability to offer selective-area coatings in a wide range of thicknesses and material choices while retaining dimensional and edge control of the coating. Complex geometries can be coated with a high materials utilization and with coating properties tailored to the end application. Porosity and bond strength values can match or exceed those seen with the best commercially available thermal sprayed coatings. The ability of the process to balance abrasion resistance and toughness requirements for a specific wear mode, is illustrated by microstructural control of the size, shape and density of carbide particles contained in the coatings. Dry sand abrasive test data are provided on Conforma Clad coatings and competitive processes. Ongoing developments of non-furnace fusion techniques, such as laser cladding, are presented and the microstructures compared with those obtained with conventional coating processes. Commercial applications for these coatings are highlighted with some typical examples.

  4. HIGH-PERFORMANCE COATING MATERIALS

    SciTech Connect

    SUGAMA,T.

    2007-01-01

    Corrosion, erosion, oxidation, and fouling by scale deposits impose critical issues in selecting the metal components used at geothermal power plants operating at brine temperatures up to 300 C. Replacing these components is very costly and time consuming. Currently, components made of titanium alloy and stainless steel commonly are employed for dealing with these problems. However, another major consideration in using these metals is not only that they are considerably more expensive than carbon steel, but also the susceptibility of corrosion-preventing passive oxide layers that develop on their outermost surface sites to reactions with brine-induced scales, such as silicate, silica, and calcite. Such reactions lead to the formation of strong interfacial bonds between the scales and oxide layers, causing the accumulation of multiple layers of scales, and the impairment of the plant component's function and efficacy; furthermore, a substantial amount of time is entailed in removing them. This cleaning operation essential for reusing the components is one of the factors causing the increase in the plant's maintenance costs. If inexpensive carbon steel components could be coated and lined with cost-effective high-hydrothermal temperature stable, anti-corrosion, -oxidation, and -fouling materials, this would improve the power plant's economic factors by engendering a considerable reduction in capital investment, and a decrease in the costs of operations and maintenance through optimized maintenance schedules.

  5. 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.

  6. Coatings for graphite fibers

    NASA Technical Reports Server (NTRS)

    Galasso, F. S.; Scola, D. A.; Veltri, R. D.

    1980-01-01

    Graphite fibers released from composites during burning or an explosion caused shorting of electrical and electronic equipment. Silicon carbide, silica, silicon nitride and boron nitride were coated on graphite fibers to increase their electrical resistances. Resistances as high as three orders of magnitude higher than uncoated fiber were attained without any significant degradation of the substrate fiber. An organo-silicone approach to produce coated fibers with high electrical resistance was also used. Celion 6000 graphite fibers were coated with an organo-silicone compound, followed by hydrolysis and pyrolysis of the coating to a silica-like material. The shear and flexural strengths of composites made from high electrically resistant fibers were considerably lower than the shear and flexural strengths of composites made from the lower electrically resistant fibers. The lower shear strengths of the composites indicated that the coatings on these fibers were weaker than the coating on the fibers which were pyrolyzed at higher temperature.

  7. Study for Blade Ceramic Coating Delamination Detection for Gas Turbine

    NASA Astrophysics Data System (ADS)

    Choi, Choul-Jun; Choi, Seung Hyun; Kim, Jae-Yeol

    The component of the hot gas path in gas turbines can survive to very high temperatures because they are protected by ceramic Thermal Barrier Coating (TBC); the failure of such coating can dramatically reduce the component life. A reliable assessment of the Coating integrity and/or an Incipient TBC Damage Detection can help both in optimizing the inspection intervals and in finding the appropriate remedial actions. This study gives the TBC integrity; so other methods are required, like thermography to obtain indications of TBC delamination. Pulsed Thermography detects coating detachments and interface defects, with a large area of view but a spatial resolution of few mm. The mentioned techniques as a whole constitute a powerful tool for the life assessment of thermal barrier coating.

  8. Applications of coatings in coal-fired energy systems

    SciTech Connect

    Natesan, K.

    1992-03-01

    Corrosion and erosion of metallic structural materials at elevated temperatures in complex multicomponent gas environments that include particulates are potential problems in many fossil energy systems, especially those using coal as a feedstock. The use of appropriate corrosion-resistant coatings on metallic components offers an avenue to minimize material degradation and extend component life. The purpose of this paper is to review the current status of coating performance in environments typical of pulverized-coal-fired boilers, coal gasification, fluidized-bed combustion, and gas turbines. The paper discusses the complexity of environments in different systems and the coating requirements for acceptable performance. Examples illustrate the morphology and corrosion/erosion performance of coating/structural alloy combinations exposed in some of these systems. La addition, future research and development needs are discussed for coating applications in several coal-fired systems.

  9. Overview of thermal barrier coatings in diesel engines

    NASA Technical Reports Server (NTRS)

    Yonushonis, T. M.

    1995-01-01

    An understanding of delamination mechanisms in thermal barrier coatings has been developed for diesel applications through nondestructive evaluation, structural analysis modeling and engine evaluation of various thermal barrier coatings. This knowledge has resulted in improved thermal barrier coatings which survive abusive cyclic fatigue tests in high output diesel engines. Significant efforts are still required to improve the plasma spray processing capability and the economics for complex geometry diesel engine components. Data obtained from advanced diesel engines on the effect of thermal barrier coatings on engine fuel economy and emission has not been encouraging. Although the underlying metal component temperatures have been reduced through the use of thermal barrier coating, engine efficiency and emission trends have not been promising.

  10. Gas turbine coatings eddy current quantitative and qualitative evaluation

    NASA Astrophysics Data System (ADS)

    Ribichini, Remo; Giolli, Carlo; Scrinzi, Erica

    2017-02-01

    Gas turbine blades (buckets) are among the most critical and expensive components of the engine. Buckets rely on protective coatings in order to withstand the harsh environment in which they operate. The thickness and the microstructure of coatings during the lifespan of a unit are fundamental to evaluate their fitness for service. A frequency scanning Eddy Current instrument can allow the measurement of the thickness and of physical properties of coatings in a Non-Destructive manner. The method employed relies on the acquisition of impedance spectra and on the inversion of the experimental data to derive the coating properties and structure using some assumptions. This article describes the experimental validation performed on several samples and real components in order to assess the performance of the instrument as a coating thickness gage. The application of the technique to support residual life assessment of serviced buckets is also presented.

  11. Microstructure and wear behavior of quasicrystalline thermal sprayed coatings

    SciTech Connect

    Sordelet, D.J.; Krotz, P.D.; Daniel, R.L. Jr.; Smith, M.F.

    1995-12-31

    An Al-Cu-Fe alloy coating which forms a quasicrystalline phase is a potential candidate for replacing electro-deposited chromium on various components in the Space Shuttle Main Engine. Coatings were deposited by air and vacuum plasma spraying and by high-velocity oxygen-fuel spraying. Finer starting powders tended to lose Al during spraying, which affected the phase equilibrium of the coatings. Coatings which retained the starting powder composition were richer in the desired quasicrystalline phase. Ball-on-disk wear tests between 440 C stainless steel ball and the Al-Cu-Fe coatings were performed. Coefficients of friction ranged from 0.60 to 1.2 for the different coatings.

  12. 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.

  13. Method for adhering a coating to a substrate structure

    DOEpatents

    Taxacher, Glenn Curtis; Crespo, Andres Garcia; Roberts, III, Herbert Chidsey

    2015-02-17

    A method for adhering a coating to a substrate structure comprises selecting a substrate structure having an outer surface oriented substantially parallel to a direction of radial stress, modifying the outer surface to provide a textured region having steps to adhere a coating thereto, and applying a coating to extend over at least a portion of the textured region, wherein the steps are oriented substantially perpendicular to the direction of radial stress to resist deformation of the coating relative to the substrate structure. A rotating component comprises a substrate structure having an outer surface oriented substantially parallel to a direction of radial stress. The outer surface defines a textured region having steps to adhere a coating thereto, and a coating extends over at least a portion of the textured region. The steps are oriented substantially perpendicular to the direction of radial stress to resist creep.

  14. Computational homogenisation for thermoviscoplasticity: application to thermally sprayed coatings

    NASA Astrophysics Data System (ADS)

    Berthelsen, Rolf; Denzer, Ralf; Oppermann, Philip; Menzel, Andreas

    2017-07-01

    Metal forming processes require wear-resistant tool surfaces in order to ensure a long life cycle of the expensive tools together with a constant high quality of the produced components. Thermal spraying is a relatively widely applied coating technique for the deposit of wear protection coatings. During these coating processes, heterogeneous coatings are deployed at high temperatures followed by quenching where residual stresses occur which strongly influence the performance of the coated tools. The objective of this article is to discuss and apply a thermo-mechanically coupled simulation framework which captures the heterogeneity of the deposited coating material. Therefore, a two-scale finite element framework for the solution of nonlinear thermo-mechanically coupled problems is elaborated and applied to the simulation of thermoviscoplastic material behaviour including nonlinear thermal softening in a geometrically linearised setting. The finite element framework and material model is demonstrated by means of numerical examples.

  15. A performance and reliability model for thermal barrier coatings

    NASA Technical Reports Server (NTRS)

    Batakis, A. P.

    1985-01-01

    A modeling technique for predicting the performance and reliability of TBC's is being developed at Solar Turbines Incorporated. The concept combines experimental coating property data with finite element analyses to predict the thermal and mechanical behavior of coating systems in service. A key feature of Solar's approach is the use of a four point flexure test to estimate coating strength distributions and to predict coating failure probability. This model was used to evaluate the effect of physical variations on coating performance in high heat flux rocket engine applications for NASA. Current work, promoted by Caterpillar Tractor Company for diesel engine applications, is being conducted to measure coating strength as a function of temperature, and future work will document strength degradation with time at temperature. Solar's interest lies in the application of TBCs to gas turbine engine components.

  16. Broadband antireflective coating for NEOSTED

    NASA Astrophysics Data System (ADS)

    Budasz, Jiří; Junek, Jiří; Václavík, Jan

    2016-11-01

    This paper deals with the development of a broadband antireflective coating for a special optical components for the NEOSTED project by European Space Agency (ESA). The aim of this work was to find a suitable design of the optical coating and to develop its production process so it meets the main requirement in which the average reflectance of the coating must be under 0.5 % for wavelengths in the range of 470 - 770 nm. The combination of titanium dioxide (TiO2) and silicon dioxide (SiO2) prepared by the ion beam assisted deposition (IBAD) was chosen for practical experiments and finally for the production as well. The final decision among the proposed designs and materials involved especially the number of layers used in the design in combination with the thickness control technology. From preproduction tests it turned out that the quartz monitor with the thickness set point correction based on a post process measurement is suitable for controlling deposited thickness in the application. This paper presents data from the preproduction tests and data from the first part of the production. A homogeneity of the deposited layer thickness was evaluated based on the measurement of the thickness across the sample.

  17. 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

  18. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2003-10-14

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  19. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2004-08-31

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  20. Electrospark deposition coatings

    NASA Astrophysics Data System (ADS)

    Sheely, W. F.

    1986-11-01

    Hard surfacing for wear resistant and low-friction coatings has been improved by means of advances in the computer controls in electronic circuitry of the electrospark deposition (ESD) process. coatings of nearly any electrically conductive metal alloy or cermet can be deposited on conductive materials. Thickness is usually two mils or less, but can be as high as 10 mils. ESD coatings can quadrupole cutting tool life.

  1. Coated 4340 Steel

    DTIC Science & Technology

    2013-08-26

    plasma vapor NAWCADPAX/TR-2013/252 2 deposition (reference 9), chemical vapor deposition, hot dip galvanizing, anodizing, composite coatings ...electroplating on 4340 steel. Assess the impact of substitute primer and sacrificial coating on corrosion fatigue and SCC, in particular leading ...alternative coatings qualified to MIL-PRE-23377 Class N and an electroplated zinc -nickel alloy passivated with a trivalent chromium solution which is

  2. Electrospark deposition coatings

    SciTech Connect

    Sheely, W.F.

    1986-11-19

    Hard surfacing for wear resistant and low-friction coatings has been improved by means of advances in the computer controls in electronic circuitry of the electrospark deposition (ESD) process. coatings of nearly any electrically conductive metal alloy or cermet can be deposited on conductive materials. Thickness is usually two mils or less, but can be as high as 10 mils. ESD coatings can quadrupole cutting tool life. (DLC)

  3. Optical coating in space

    NASA Technical Reports Server (NTRS)

    Bunner, A. N.

    1983-01-01

    A technological appraisal of the steps required to approach the goal of in-situ optical coating, cleaning and re-coating the optical elements of a remote telescope in space is reported. Emphasis is placed on the high ultraviolet throughput that a telescope using bare aluminum mirrors would offer. A preliminary design is suggested for an Orbital Coating Laboratory to answer basic technical questions.

  4. Advanced Multifunctional Coating

    DTIC Science & Technology

    2011-08-17

    and UV durability of then current chrome free TT-P-2756 SPTC • Leverage APC technology into SPTC • Coating uses same fluoropolyurethane technology...as APC currently used on C-17 • Leverage recent advances in chrome free corrosion inhibitor technology • State of the art chrome free corrosion...coat exposed metal Aluminum Base Metal Original Finish System Aged APC Topcoat Conversion Coat Chromic Acid Anodize Aluminum Cladding Original Primer

  5. Platelet Composite Coatings for Tin Whisker Mitigation

    NASA Astrophysics Data System (ADS)

    Rohwer, Lauren E. S.; Martin, James E.

    2015-11-01

    Reliable methods for tin whisker mitigation are needed for applications that utilize tin-plated commercial components. Tin can grow whiskers that can lead to electrical shorting, possibly causing critical systems to fail catastrophically. The mechanisms of tin whisker growth are unclear and this makes prediction of the lifetimes of critical components uncertain. The development of robust methods for tin whisker mitigation is currently the best approach to eliminating the risk of shorting. Current mitigation methods are based on unfilled polymer coatings that are not impenetrable to tin whiskers. In this paper we report tin whisker mitigation results for several filled polymer coatings. The whisker-penetration resistance of the coatings was evaluated at elevated temperature and high humidity and under temperature cycling conditions. The composite coatings comprised Ni and MgF2-coated Al/Ni/Al platelets in epoxy resin or silicone rubber. In addition to improved whisker mitigation, these platelet composites have enhanced thermal conductivity and dielectric constant compared with unfilled polymers.

  6. Platelet composite coatings for tin whisker mitigation

    SciTech Connect

    Rohwer, Lauren E. S.; Martin, James E.

    2015-09-14

    In this study, reliable methods for tin whisker mitigation are needed for applications that utilize tin-plated commercial components. Tin can grow whiskers that can lead to electrical shorting, possibly causing critical systems to fail catastrophically. The mechanisms of tin whisker growth are unclear and this makes prediction of the lifetimes of critical components uncertain. The development of robust methods for tin whisker mitigation is currently the best approach to eliminating the risk of shorting. Current mitigation methods are based on unfilled polymer coatings that are not impenetrable to tin whiskers. In this paper we report tin whisker mitigation results for several filled polymer coatings. The whisker-penetration resistance of the coatings was evaluated at elevated temperature and high humidity and under temperature cycling conditions. The composite coatings comprised Ni and MgF2-coated Al/Ni/Al platelets in epoxy resin or silicone rubber. In addition to improved whisker mitigation, these platelet composites have enhanced thermal conductivity and dielectric constant compared with unfilled polymers.

  7. Platelet composite coatings for tin whisker mitigation

    DOE PAGES

    Rohwer, Lauren E. S.; Martin, James E.

    2015-09-14

    In this study, reliable methods for tin whisker mitigation are needed for applications that utilize tin-plated commercial components. Tin can grow whiskers that can lead to electrical shorting, possibly causing critical systems to fail catastrophically. The mechanisms of tin whisker growth are unclear and this makes prediction of the lifetimes of critical components uncertain. The development of robust methods for tin whisker mitigation is currently the best approach to eliminating the risk of shorting. Current mitigation methods are based on unfilled polymer coatings that are not impenetrable to tin whiskers. In this paper we report tin whisker mitigation results formore » several filled polymer coatings. The whisker-penetration resistance of the coatings was evaluated at elevated temperature and high humidity and under temperature cycling conditions. The composite coatings comprised Ni and MgF2-coated Al/Ni/Al platelets in epoxy resin or silicone rubber. In addition to improved whisker mitigation, these platelet composites have enhanced thermal conductivity and dielectric constant compared with unfilled polymers.« less

  8. Robotic weld overlay coatings for erosion control

    SciTech Connect

    Not Available

    1994-11-01

    The erosion of materials by the impact of solid particles has received increasing attention during the past twenty years. Recently, research has been initiated with the event of advanced coal conversion processes in which erosion plays an important role. The resulting damage, termed Solid Particle Erosion (SPE), is of concern primarily because of the significantly increased operating costs which result in material failures. Reduced power plant efficiency due to solid particle erosion of boiler tubes and waterfalls has led to various methods to combat SPE. One method is to apply coatings to the components subjected to erosive environments. Protective weld overlay coatings are particularly advantageous in terms of coating quality. The weld overlay coatings are essentially immune to spallation due to a strong metallurgical bond with the substrate material. By using powder mixtures, multiple alloys can be mixed in order to achieve the best performance in an erosive environment. However, a review of the literature revealed a lack of information on weld overlay coating performance in erosive environments which makes the selection of weld overlay alloys a difficult task. The objective of this project is to determine the effects of weld overlay coating composition and microstructure on erosion resistance. These results will lead to a better understanding of erosion mitigation in CFB`s.

  9. Robotic weld overlay coatings for erosion control

    NASA Astrophysics Data System (ADS)

    The erosion of materials by the impact of solid particles has received increasing attention during the past twenty years. Recently, research has been initiated with the event of advanced coal conversion processes in which erosion plays an important role. The resulting damage, termed Solid Particle Erosion (SPE), is of concern primarily because of the significantly increased operating costs which result in material failures. Reduced power plant efficiency due to solid particle erosion of boiler tubes and waterfalls has led to various methods to combat SPE. One method is to apply coatings to the components subjected to erosive environments. Protective weld overlay coatings are particularly advantageous in terms of coating quality. The weld overlay coatings are essentially immune to spallation due to a strong metallurgical bond with the substrate material. By using powder mixtures, multiple alloys can be mixed in order to achieve the best performance in an erosive environment. However, a review of the literature revealed a lack of information on weld overlay coating performance in erosive environments which makes the selection of weld overlay alloys a difficult task. The objective of this project is to determine the effects of weld overlay coating composition and microstructure on erosion resistance. These results will lead to a better understanding of erosion mitigation in CFB's.

  10. Biophysical Studies of the Cell Coat

    NASA Astrophysics Data System (ADS)

    Curtis, Jennifer

    2009-11-01

    Many mammalian cell types are enveloped by a coat of polysaccharides and proteins. This coat influences vital biological processes such as cell adhesion, proliferation, motility and embryogenesis. The constitution and thickness of this layer, referred to as the pericellular coat (PCC), pericellular matrix or glycocalyx, can vary considerably. Despite its significance, the macromolecular organization of the cell coat remains speculative. Here we focus on cell coats whose vital structural backbone is hyaluronan (HA), a highly-hydrated polysaccharide that anchors the coat to the cell membrane. The molecular interaction of HA with different HA-binding proteins determines the architecture of the PCC. The resultant mesoscopic arrangement of the different PCC components influences the cell's perception of the extracellular environment and its ability to withstand compression. The stress transduction through the PCC is especially important for chondrocytes, cells located in the load-bearing cartilage. The molecular structure of some PCC components, especially the HA-binding protein aggrecan, changes with age or osteoarthritis. These changes alter the viscoelasticity of the PCC and may also affect its molecular architecture. We employ a combination of passive microrheology and optical force probe microscopy on the PCC of living rat chondrocytes (RCJ-P) cells, which serve as a well-established model system for HA-rich coats. We establish the first micromechanical map of the PCC which reveals an increase in both the viscosity and elasticity of the PCC towards the cell surface. Further, we characterize the distribution of HA and observe a linear increase in fluorescence intensity towards the cell membrane. Comparing the results of these approaches using polymer theory sheds light on the macromolecular architecture of the PCC. Our data indicate that the structure of PCC is far more complex than expected from a pure end-grafted polymer brush.

  11. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A series of studies in which films and liquid spray-on materials were evaluated in the laboratory for transport aircraft external surface coatings are summarized. Elastomeric polyurethanes were found to best meet requirements. Two commercially available products, CAAPCO B-274 and Chemglaze M313, were subjected to further laboratory testing, airline service evaluations, and drag-measurement flight tests. It was found that these coatings were compatible with the severe operating environment of airlines and that coatings reduced airplane drag. An economic analysis indicated significant dollar benefits to airlines from application of the coatings.

  12. Coatings for Graphite Fibers

    NASA Technical Reports Server (NTRS)

    Galasso, F. S.; Scola, D. A.; Veltri, R. D.

    1980-01-01

    Several approaches for applying high resistance coatings continuously to graphite yarn were investigated. Two of the most promising approaches involved (1) chemically vapor depositing (CVD) SiC coatings on the surface of the fiber followed by oxidation, and (2) drawing the graphite yarn through an organo-silicone solution followed by heat treatments. In both methods, coated fibers were obtained which exhibited increased electrical resistances over untreated fibers and which were not degraded. This work was conducted in a previous program. In this program, the continuous CVD SiC coating process used on HTS fiber was extended to the coating of HMS, Celion 6000, Celion 12000 and T-300 graphite fiber. Electrical resistances three order of magnitude greater than the uncoated fiber were measured with no significant degradation of the fiber strength. Graphite fibers coated with CVD Si3N4 and BN had resistances greater than 10(exp 6) ohm/cm. Lower pyrolysis temperatures were used in preparing the silica-like coatings also resulting in resistances as high as three orders of magnitude higher than the uncoated fiber. The epoxy matrix composites prepared using these coated fibers had low shear strengths indicating that the coatings were weak.

  13. Zinc phosphate conversion coatings

    DOEpatents

    Sugama, T.

    1997-02-18

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate {alpha}-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal. 33 figs.

  14. Zinc phosphate conversion coatings

    DOEpatents

    Sugama, Toshifumi

    1997-01-01

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate .alpha.-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal.

  15. Oxide coating development

    SciTech Connect

    Stinton, D.P.

    1995-06-01

    Monolithic SiC heat exchangers and fiber-reinforced SiC-matrix composite heat exchangers and filters are susceptible to corrosion by alkali metals at elevated temperatures. Protective coatings are currently being developed to isolate the SiC materials from the corrodants. Unfortunately, these coatings typically crack and spall when applied to SiC substrates. The purpose of this task is to determine the feasibility of using a compliant material between the protective coating and the substrate. The low-modulus compliant layer could absorb stresses and eliminate cracking and spalling of the protective coatings.

  16. Development and Fatigue Testing of Ceramic Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Choi, Sung R.; Miller, Robert A.

    2004-01-01

    Ceramic thermal barrier coatings will play an increasingly important role in future gas turbine engines because of their ability to effectively protect the engine components and further raise engine temperatures. Durability of the coating systems remains a critical issue with the ever-increasing temperature requirements. Thermal conductivity increase and coating degradation due to sintering and phase changes are known to be detrimental to coating performance. There is a need to characterize the coating thermal fatigue behavior and temperature limit, in order to potentially take full advantage of the current coating capability. In this study, thermal conductivity and cyclic fatigue behaviors of plasma-sprayed ZrO2-8wt%Y2O3 thermal barrier coatings were evaluated under high temperature, large thermal gradient and thermal cycling conditions. The coating degradation and failure processes were assessed by real-time monitoring of the coating thermal conductivity under the test conditions. The ceramic coating crack initiation and propagation driving forces and failure modes under the cyclic thermal loads will be discussed in light of the high temperature mechanical fatigue and fracture testing results.

  17. A Novel Type of Environmentally Friendly Slurry Coatings

    NASA Astrophysics Data System (ADS)

    Montero, Xabier; Galetz, Mathias C.; Schütze, Michael

    2015-01-01

    A variety of commercial slurries are available to aluminize the surfaces of nickel-based superalloys; however, they have three main disadvantages. First, the phosphates and chromates or halides used as binders or to activate the diffusion species are environmentally harmful and toxic; second, the slurry coatings can only produce high-aluminum-activity coatings which form precipitate-rich coatings that are detrimental to adherence. Finally, these coatings are limited to the incorporation of aluminum and silicon, whereas the co-deposition of other elements such as chromium or cobalt has not been achieved so far. In this work, the limitations of slurry coatings have been overcome by carefully designing the powder composition and controlling the process to produce co-deposition coatings with chromium, cobalt, or nickel by using nontoxic water-based slurries. This also opens an effective way to control Al activity and to produce low-activity aluminized coatings for the first time when using the slurry technique. These results expand the application range of slurry coatings so they can also be applied under ambient atmosphere, making it possible to fully coat aero engine pieces or large-scale industrial components, providing all properties that are usually only achieved by using more complex and expensive methods such as chemical vapor deposition. Furthermore, these new coatings offer unique advantages that can be very favorable especially as a repairing technique.

  18. Strain Compatible Oxidation and Corrosion Protection Coatings for Enhanced Thermo-Mechanical Durability of Turbine Airfoils

    DTIC Science & Technology

    2011-12-05

    Report: Grant N00014-08-0331 Technical Objectives As critical components of advanced aircraft engines , turbine airfoils require coatings for...advanced aircrafi engines , turbine airfoils require coatings for enhancement of oxidation, corrosion and thermal capabilities . Airfoil coatings ofien...Oxidation and Corrosion Protection Coatings for Enhanced Thermo-Mechanical Durability of Turbine Airfoils 5b. GRANT NUMBER N00014-08-l-0331 5c

  19. METAL-MATRIX COMPOSITES AND THERMAL SPRAY COATINGS FOR EARTH MOVING MACHINES

    SciTech Connect

    D. Trent Weaver; Matthew T. Kiser

    2003-10-01

    In the 11th quarter, further testing was performed on thermal spray coatings. A component coated and fused in the 9th quarter underwent high-stress abrasive wear testing. The test successfully showed this coating could survive in a high stress, sliding wear environment as the base layer in an FGM design coating. Work on the ferrous metal-matrix composites was completed in previous quarter and therefore no update is provided.

  20. Structurally Integrated, Damage Tolerant Thermal Spray Coatings: Processing Effects on Surface and System Functionalities

    NASA Astrophysics Data System (ADS)

    Vackel, Andrew

    Thermal Spray (TS) coatings have seen extensive application as protective surfaces to enhance the service life of substrates prone to damage in their operating environment (wear, corrosion, heat etc.). With the advent of high velocity TS processes, the ability to deposit highly dense (>99%) metallic and cermet coatings has further enhanced the protective ability of these coatings. In addition to surface functionality, the influence of the coating application on the mechanical performance of a coated component is of great concern when such a component will experience either static or cyclic loading during service. Using a process mapping methodology, the processing-property interplay between coating materials meant to provide damage tolerant surface or for structural restoration are explored in terms of relevant mechanical properties. Most importantly, the residual stresses inherent in TS deposited coatings are shown to play a significant role in the integrated mechanical performance of these coatings. Unique to high velocity TS processes is the ability to produce compressive stresses within the deposit from the cold working induced by the high kinetic energy particles upon impact. The extent of these formation stresses are explored with different coating materials, as well as processing influence. The ability of dense TS coatings to carry significant structural load and synergistically strengthen coated tensile specimens is demonstrated as a function of coating material, processing, and thickness. The sharing of load between the substrate and otherwise brittle coating enables higher loads before yield for the bi-material specimens, offering a methodology to improve the tensile performance of coated components for structural repair or multi-functionality (surface and structure). The concern of cyclic fatigue damage in coated components is explored, since the majority of service application are designed for loading to be well below the yield point. The role of

  1. Emittance and absorptance of NASA ceramic thermal barrier coating system. [for turbine cooling

    NASA Technical Reports Server (NTRS)

    Liebert, C. H.

    1978-01-01

    Spectral emittance measurements were made on a two-layer ceramic thermal barrier coating system consisting of a metal substrate, a NiCrAly bond coating and a yttria-stabilized zirconia ceramic coating. Spectral emittance data were obtained for the coating system at temperatures of 300 to 1590 K, ceramic thickness of zero to 0.076 centimeter, and wavelengths of 0.4 to 14.6 micrometers. The data were transformed into total hemispherical emittance values and correlated with respect to ceramic coating thickness and temperature using multiple regression curve fitting techniques. The results show that the ceramic thermal barrier coating system is highly reflective and significantly reduces radiation heat loads on cooled gas turbine engine components. Calculation of the radiant heat transfer within the nonisothermal, translucent ceramic coating material shows that the gas-side ceramic coating surface temperature can be used in heat transfer analysis of radiation heat loads on the coating system.

  2. [What effect does the hydroxyapatite coating have in cementless knee arthroplasty?].

    PubMed

    Hildebrand, R; Trappmann, D; Georg, C; Müller, H H; Koller, M; Klose, K J; Griss, P; Kienapfel, H

    2003-04-01

    The goal of this study was to compare the migration of noncemented diffusion sintered titanium fibermesh-coated tibial components with (HA group) and without (non-HA group) additional hydroxyapatite coating. For this purpose digital radiostereometry (DIRSA) was used to compare the migration after 2 and 9 years for the two groups. After 2 years the mean maximum subsidence of the HA-coated components (0.24+/-0.18 mm) was about one-half of the mean maximum subsidence of the non-HA-coated group (0.55+/-0.55 mm). After 9 years the maximum subsidence of the HA-coated components was still smaller, but not as pronounced as before. The same trend was also found for the endpoint maximum total point motion (MTPM). After 2 years the mean MTPM of the HA-coated components was 0.66+/-0.38 mm and of the non-HA group 0.73+/-0.50 mm. After 9 years the mean MTPM for the HA-coated components was 0.54+/-0.15 mm and for the non-HA-coated components 0.74+/-0.20 mm. None of the HA-coated tibial components but one of the non-HA group had to be revised and exchanged due to aseptic loosening.

  3. Transformation of nacre coatings into apatite coatings in phosphate buffer solution at low temperature.

    PubMed

    Guo, Yaping; Zhou, Yu

    2008-08-01

    Nacre coatings were deposited on Ti6Al4V substrates by electrophoretic technique, and subsequently converted into apatite coatings with hierarchical porous structures by treatment with a phosphate buffer solution. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma optical emission spectroscopy, X-ray photoelectron spectroscopy (XPS), and N(2) adsorption-desorption isotherms. The results show that the nacre coatings are converted into the plate-like apatite coatings via a dissolution-precipitation reaction, while the organic components of the nacre are reserved. The mesopores with pore size of 4.4 nm are formed within the plate-like structure, and the macropores are formed among the plate-like structure. Simulated body fluid (SBF) immersion tests reveal that the apatite coatings have a good in vitro bioactivity. Bone-like apatite crystals are formed on the surfaces of the apatite coatings after soaking in SBF for 12 h, and fill up the macropores on the coatings with increasing the soaking time. In addition, XPS indicates that a TiO(x) layer and PO(4) (3-) ions appear on the substrate surfaces by pretreatment with a H(3)PO(4)/HF solution. The TiO(x) layer and PO(4) (3-) ions can induce the formation of apatite crystals, resulting in a composition gradient from the oxide layer to the external apatite layer.

  4. Thermal and Environmental Barrier Coating Development for Advanced Propulsion Engine Systems

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.; Fox, Dennis S.

    2008-01-01

    Ceramic thermal and environmental barrier coatings (TEBCs) are used in gas turbine engines to protect engine hot-section components in the harsh combustion environments, and extend component lifetimes. Advanced TEBCs that have significantly lower thermal conductivity, better thermal stability and higher toughness than current coatings will be beneficial for future low emission and high performance propulsion engine systems. In this paper, ceramic coating design and testing considerations will be described for turbine engine high temperature and high-heat-flux applications. Thermal barrier coatings for metallic turbine airfoils and thermal/environmental barrier coatings for SiC/SiC ceramic matrix composite (CMC) components for future supersonic aircraft propulsion engines will be emphasized. Further coating capability and durability improvements for the engine hot-section component applications can be expected by utilizing advanced modeling and design tools.

  5. Molybdenum protective coatings adhesion to steel substrate

    NASA Astrophysics Data System (ADS)

    Blesman, A. I.; Postnikov, D. V.; Polonyankin, D. A.; Teplouhov, A. A.; Tyukin, A. V.; Tkachenko, E. A.

    2017-06-01

    Protection of the critical parts, components and assemblies from corrosion is an urgent engineering problem and many other industries. Protective coatings’ forming on surface of metal products is a promising way of corrosionprevention. The adhesion force is one of the main characteristics of coatings’ durability. The paper presents theoretical and experimental adhesion force assessment for coatings formed by molybdenum magnetron sputtering ontoa steel substrate. Validity and reliability of results obtained by simulation and sclerometry method allow applying the developed model for adhesion force evaluation in binary «steel-coating» systems.

  6. Thermal barrier coating life prediction model development

    NASA Technical Reports Server (NTRS)

    Meier, Susan M.; Nissley, David M.; Sheffler, Keith D.; Cruse, Thomas A.

    1991-01-01

    A thermal barrier coated (TBC) turbine component design system, including an accurate TBC life prediction model, is needed to realize the full potential of available TBC engine performance and/or durability benefits. The objective of this work, which was sponsored in part by NASA, was to generate a life prediction model for electron beam - physical vapor deposited (EB-PVD) zirconia TBC. Specific results include EB-PVD zirconia mechanical and physical properties, coating adherence strength measurements, interfacial oxide growth characteristics, quantitative cyclic thermal spallation life data, and a spallation life model.

  7. Turning of thick thermal spray coatings

    NASA Astrophysics Data System (ADS)

    López de Lacalle, L. N.; Lamikiz, A.; Fernandes, M. H.; Gutiérrez, A.; Sánchez, J. A.

    2001-06-01

    This technical note looks at several attempts to machine parts coated with Ni5Al thermal spray. This coating is used in the overhaul and repair of gas turbine components. Machining the thermal sprays to achieve the dimensional tolerances and surface finish is needed. Turning tests were performed with small carbide inserts and with CBN. A study was made of tool performance and cutting process. In this way, tool life, wear mechanism, chip formation process, and actual roughness of turned parts were analyzed. In addition to the good performance of CBN inserts, some disadvantages of using coolant with CBN tools were detected and analyzed.

  8. Protective metal matrix coating with nanocomponents

    NASA Astrophysics Data System (ADS)

    Galevsky, G. V.; Rudneva, V. V.; Cherepanov, A. N.; Galevsky, S. G.; Efimova, K. A.

    2016-09-01

    Experience of nanocrystalline chromium, titanium, silicon carbides and borides components application as nickel, zinc, chromium based electrodeposited composite coating is generalized. Electrodepositing conditions are determined. Structure and physicochemical properties of coatings, namely micro-hardness, adhesion to steel base, inherent stresses, heat resistance, corrosion currents, en-during quality, and their change during isothermal annealing are studied. As is shown, nanocomponents act as metal matrix modifier. Technological and economic feasibility study to evaluate expediency of replacing high priced nano-diamonds with nanocrystalline borides and carbides is undertaken.

  9. Combustion chemical vapor deposited coatings for thermal barrier coating systems

    SciTech Connect

    Hampikian, J.M.; Carter, W.B.

    1995-12-31

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings. In this report, the evaluation of alumina and ceria coatings on a nickel-chromium alloy is described.

  10. Program for plasma-sprayed self-lubricating coatings

    NASA Technical Reports Server (NTRS)

    Walther, G. C.

    1979-01-01

    A method for preparing composite powders of the three coating components was developed and a procedure that can be used in applying uniform coatings of the composite powders was demonstrated. Composite powders were prepared by adjusting particle sizes of the components and employing a small amount of monoaluminum phosphate as an inorganic binder. Quantitative microscopy (image analysis) was found to be a convenient method of characterizing the composition of the multiphase plasma-sprayed coatings. Area percentages and distribution of the components were readily obtained by this method. The adhesive strength of the coating to a nickel-chromium alloy substrate was increased by about 40 percent by a heat treatment of 20 hours at 650 C.

  11. Vacuum-deposited optical coatings experiment (A0138-4)

    NASA Technical Reports Server (NTRS)

    Malherbe, A.

    1984-01-01

    The stability of various vacuum deposited optical coatings exposed to the space environment were analyzed. A wide range of optical components manufactured by vacuum deposition, such as metallic and multidielectric reflective coatings in the UV range, metal dielectric interference filtes in the UV and IR ranges, narrow-bandpass filters int he near-UV and visible ranges, selective metallic mirrors in the range from 1500 to 2500 A. antireflective and reflective IR coatings, beam splitters in the visible and IR ranges, and optical surface reflection (OSR) coatings were developed. Many of these components were incorporated into scientific and technical experiments flown on balloons and rockets as well as on Symphonie, Meteosate, OTS, D2-B, TIROS n, and others. It appears that these components operate successfully in flight.

  12. Additive manufacturing of optical components

    NASA Astrophysics Data System (ADS)

    Heinrich, Andreas; Rank, Manuel; Maillard, Philippe; Suckow, Anne; Bauckhage, Yannick; Rößler, Patrick; Lang, Johannes; Shariff, Fatin; Pekrul, Sven

    2016-08-01

    The development of additive manufacturing methods has enlarged rapidly in recent years. Thereby, the work mainly focuses on the realization of mechanical components, but the additive manufacturing technology offers a high potential in the field of optics as well. Owing to new design possibilities, completely new solutions are possible. This article briefly reviews and compares the most important additive manufacturing methods for polymer optics. Additionally, it points out the characteristics of additive manufactured polymer optics. Thereby, surface quality is of crucial importance. In order to improve it, appropriate post-processing steps are necessary (e.g. robot polishing or coating), which will be discussed. An essential part of this paper deals with various additive manufactured optical components and their use, especially in optical systems for shape metrology (e.g. borehole sensor, tilt sensor, freeform surface sensor, fisheye lens). The examples should demonstrate the potentials and limitations of optical components produced by additive manufacturing.

  13. Duplex aluminized coatings

    NASA Technical Reports Server (NTRS)

    Gedwill, M. A.; Grisaffe, S. J. (Inventor)

    1975-01-01

    The surface of a metallic base system is initially coated with a metallic alloy layer that is ductile and oxidation resistant. An aluminide coating is then applied to the metallic alloy layer. The chemistry of the metallic alloy layer is such that the oxidation resistance of the subsequently aluminized outermost layer is not seriously degraded.

  14. Coated ceramic breeder materials

    DOEpatents

    Tam, Shiu-Wing; Johnson, Carl E.

    1987-01-01

    A breeder material for use in a breeder blanket of a nuclear reactor is disclosed. The breeder material comprises a core material of lithium containing ceramic particles which has been coated with a neutron multiplier such as Be or BeO, which coating has a higher thermal conductivity than the core material.

  15. Polyphosphazene Icephobic Coating Materials

    NASA Technical Reports Server (NTRS)

    Willis, Paul B.

    1992-01-01

    Coating materials consisting mostly of modified polyphosphazene (Class FZ) elastomers provide better protection against icing than fluorocarbon polymers and silicone elastomers. Reduces adhesive force between ice and surface. As consequence, increasing weight of ice, wind loading, or vibration of surface causes ice to be shed. New icephobic coats reduce accumulation of ice on aircraft, radomes, antennas, ships, and power-transmission lines.

  16. Stoichiometric tungsten carbide coatings

    NASA Astrophysics Data System (ADS)

    Hirata, G. A.; Contreras, O.; Farías, M. H.; Cota-Araiza, L.

    1996-07-01

    Filament Assisted Chemical Vapor Deposition (FA-CVD) technique has been used to prepare tungsten carbide (WC) thin films. With this simple technique we obtained polycrystalline and stoichiometric WC coatings deposited on crystalline silicon and on stainless steel substrates. Tungsten carbide coatings were studied with Auger Electron Spectroscopy and Scanning Electron Microscopy.

  17. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S. (Inventor)

    1985-01-01

    An oxide thermal barrier coating comprises ZrO3-Yb2O3 that is plasma sprayed onto a previously applied bond coating. The zirconia is partially stabilized with about 124 w/o ytterbia to insure cubic, monoclinic, and terragonal phases.

  18. Anti-Corrosion Coating

    NASA Technical Reports Server (NTRS)

    1977-01-01

    NASA-Goddard developed a zinc-rich coating with a special binder that exhibits longer life and booths with the air purifiers. superior adhesion characteristics-so that only a single coat is required. Unlike conventional coatings, . the NASA compound is easy to mix and it requires no straining before application; its materials also cost less. Thus the new coating offers cost advantages in materials, labor hours per application, and fewer applications over a given time span. The NASA coating is now undergoing test on a number of coastal area structures. In a cooperative effort with the Philadelphia Mayor's Science and Technology Council, the coating has been applied to sample sections of the Frankford Elevated System's steel support structure. On the West Coast, it is being tested on facilities of the Pillar Point Satellite Tracking Station, Pillar Point, Cat. and on segments of the Golden Gate Bridge. It is also undergoing evaluation as an undercoating to protect road equipment against de-icing salts; the coating was applied to the underside of a truck and its performance is being recorded periodically by the Vermont Department of Highways. NASA has issued patent licenses to two paint companies and the coating is expected to be commercially available this year.

  19. Molecular Adsorber Coating

    NASA Technical Reports Server (NTRS)

    Straka, Sharon; Peters, Wanda; Hasegawa, Mark; Hedgeland, Randy; Petro, John; Novo-Gradac, Kevin; Wong, Alfred; Triolo, Jack; Miller, Cory

    2011-01-01

    A document discusses a zeolite-based sprayable molecular adsorber coating that has been developed to alleviate the size and weight issues of current ceramic puck-based technology, while providing a configuration that more projects can use to protect against degradation from outgassed materials within a spacecraft, particularly contamination-sensitive instruments. This coating system demonstrates five times the adsorption capacity of previously developed adsorber coating slurries. The molecular adsorber formulation was developed and refined, and a procedure for spray application was developed. Samples were spray-coated and tested for capacity, thermal optical/radiative properties, coating adhesion, and thermal cycling. Work performed during this study indicates that the molecular adsorber formulation can be applied to aluminum, stainless steel, or other metal substrates that can accept silicate-based coatings. The coating can also function as a thermal- control coating. This adsorber will dramatically reduce the mass and volume restrictions, and is less expensive than the currently used molecular adsorber puck design.

  20. Coated ceramic breeder materials

    DOEpatents

    Tam, Shiu-Wing; Johnson, Carl E.

    1987-04-07

    A breeder material for use in a breeder blanket of a nuclear reactor is disclosed. The breeder material comprises a core material of lithium containing ceramic particles which has been coated with a neutron multiplier such as Be or BeO, which coating has a higher thermal conductivity than the core material.

  1. Polymer Coatings Degradation Properties

    DTIC Science & Technology

    1985-02-01

    transfrom infrared spectroscopy. Denisenko, L. V., et. al.; Kompoz. Polim . Mater. Date: 1982 Volume: 14, Pages: 37-39 New polyurethane coating materials and...Date: 1981 Pages: 247-254 Is the salt fog test an effective method to evaluate corrosion resistant coatings? Maiorova, N. V., et.al., Modif. Polim

  2. Coated electroactive materials

    DOEpatents

    Amine, Khalil; Abouimrane, Ali

    2016-08-30

    A process includes suspending an electroactive material in a solvent, suspending or dissolving a carbon precursor in the solvent; and depositing the carbon precursor on the electroactive material to form a carbon-coated electroactive material. Compositions include a graphene-coated electroactive material prepared from a solution phase mixture or suspension of an electroactive material and graphene, graphene oxide, or a mixture thereof.

  3. LEVELING METAL COATINGS

    DOEpatents

    Gage, H.A.

    1959-02-10

    A method is described for applying metallic coatings to a cylinder of uranium. An aluminum-silicon coat is applied by a process consisting of first cleaning the article by immersion for 5 minutes in 50% nitric acid at 65 C. The article then is dipped through a flux, prepared by adding 10% sodium fluoride to 90% of a flux comprising 53% potassium chloride, 42% lithium chloride, and 5% sodium chloride at 560 for 2 minutes and then directly into a molten metal bath comprising 99% aluminun and 12% silicon at 620 C for 3 minutes. While the coating is yet molten the article is transferred to a pair of steel rollers and rolled until the coating solidifies. By varying the composition of the flux other metals such as zinc, lead or the like may be coated on uranium in a similar manner.

  4. Catalytic thermal barrier coatings

    DOEpatents

    Kulkarni, Anand A.; Campbell, Christian X.; Subramanian, Ramesh

    2009-06-02

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

  5. Coated carbonaceous material

    SciTech Connect

    Young, C.B.F.

    1989-04-18

    This patent describes a coated fuel product comprising a piece of charcoal, and a glossy coating of paraffin completely enclosing the piece of charcoal, the charcoal further including a flammable liquid therein, the flammable liquid consisting of a light kerosene product and being sealed within the charcoal by the coating, the coating of paraffin consisting of from about 3 percent to about 7 percent by weight of the fuel product, and the flammable liquid consisting of from about 7 percent to 12 percent by weight of the fuel product. It also describes a similar product further including an additive for increasing the gloss of the coating, the additive being selected from the group consisting of polyethylene, stearic amide and monocrystalline wax.

  6. Thermal barrier coatings

    DOEpatents

    Alvin, Mary Anne [Pittsburg, PA

    2010-06-22

    This disclosure addresses the issue of providing a metallic-ceramic overlay coating that potentially serves as an interface or bond coat layer to provide enhanced oxidation resistance to the underlying superalloy substrate via the formation of a diffusion barrier regime within the supporting base material. Furthermore, the metallic-ceramic coating is expected to limit the growth of a continuous thermally grown oxide (TGO) layer that has been primarily considered to be the principal cause for failure of existing TBC systems. Compositional compatibility of the metallic-ceramic with traditional yttria-stabilized zirconia (YSZ) top coats is provided to further limit debond or spallation of the coating during operational use. A metallic-ceramic architecture is disclosed wherein enhanced oxidation resistance is imparted to the surface of nickel-based superalloy or single crystal metal substrate, with simultaneous integration of the yttria stabilized zirconia (YSZ) within the metallic-ceramic overlayer.

  7. Aerocoat 7 Replacement Coatings

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Kennedy Space Center has used Aerocoat 7 (AR-7) to protect stainless-steel flex hoses at Launch Complex (LC-39) and hydraulic lines of the Mobile Launcher Platform (MLP) because it provides excellent corrosion protection in low-temperature applications. The Sovereign Company produced AR-7 exclusively for NASA but discontinued production because the coating released high levels of volatile organic compounds (VOCs) and had a significant environmental impact. The purpose of this project was to select and evaluate potential replacement coatings for AR-7 that would be more environmentally sound. The physical and mechanical properties of commercially available coatings were investigated through the Internet. The ideal coating would be fluid enough to penetrate the outer mesh of a stainless-steel flex hose and coat the inner hose, and flexible enough to withstand the movement of the hose, as well as the expansion and contraction of its metal caused by changes in temperature.

  8. 21 CFR 175.230 - Hot-melt strippable food coatings.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Hot-melt strippable food coatings. 175.230 Section 175.230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT FOOD ADDITIVES: ADHESIVES AND COMPONENTS OF COATINGS Substances for Use as Components...

  9. The central role of wood biology in understanding the durability of wood-coating interactions

    Treesearch

    Alex C. Wiedenhoeft

    2007-01-01

    To design effectively for durability, one must actively and honestly assess the material properties and limitations of each of the components in the design system; wood or wood composite, and the coating. Inasmuch as wood coatings are manufactured to specified tolerances from known materials, we have control of that component of the system. Compared to manmade...

  10. Kinetic Monte Carlo Simulations of Diffusion in Environmental Barrier Coating Materials

    NASA Technical Reports Server (NTRS)

    Good, Brian

    2017-01-01

    Ceramic Matrix Components (CMC) components for use in turbine engines offer a number of advantages compared with current practice. However, such components are subject to degradation through a variety of mechanisms. In particular, in the hot environment inside a turbine in operation a considerable amount of water vapor is present, and this can lead to corrosion and recession. Environmental Barrier Coating (EBC) systems that limit the amount of oxygen and water reaching the component are required to reduce this degradation and extend component life. A number of silicate-based materials are under consideration for use in such coating systems, including Yttterbium and Yttrium di- and monosilicates. In this work, we present results of kinetic Monte Carlo computer simulations of oxygen diffusion in Yttrium disilicate, and compare with previous work on Yttterbium disilicate. Coatings may also exhibit cracking, and the cracks can provide a direct path for oxygen to reach the component. There is typically a bond coat between the coating and component surface, but the bond coat material is generally chosen for properties other than low oxygen diffusivity. Nevertheless, the degree to which the bond coat can inhibit oxygen diffusion is of interest, as it may form the final defense against oxygen impingement on the component. We have therefore performed similar simulations of oxygen diffusion through HfSiO4, a proposed bond coat material.

  11. Lower-Conductivity Ceramic Materials for Thermal-Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.; Zhu, Dongming

    2006-01-01

    Doped pyrochlore oxides of a type described below are under consideration as alternative materials for high-temperature thermal-barrier coatings (TBCs). In comparison with partially-yttria-stabilized zirconia (YSZ), which is the state-of-the-art TBC material now in commercial use, these doped pyrochlore oxides exhibit lower thermal conductivities, which could be exploited to obtain the following advantages: For a given difference in temperature between an outer coating surface and the coating/substrate interface, the coating could be thinner. Reductions in coating thicknesses could translate to reductions in weight of hot-section components of turbine engines (e.g., combustor liners, blades, and vanes) to which TBCs are typically applied. For a given coating thickness, the difference in temperature between the outer coating surface and the coating/substrate interface could be greater. For turbine engines, this could translate to higher operating temperatures, with consequent increases in efficiency and reductions in polluting emissions. TBCs are needed because the temperatures in some turbine-engine hot sections exceed the maximum temperatures that the substrate materials (superalloys, Si-based ceramics, and others) can withstand. YSZ TBCs are applied to engine components as thin layers by plasma spraying or electron-beam physical vapor deposition. During operation at higher temperatures, YSZ layers undergo sintering, which increases their thermal conductivities and thereby renders them less effective as TBCs. Moreover, the sintered YSZ TBCs are less tolerant of stress and strain and, hence, are less durable.

  12. R and AR optical coatings for high-power laser and for X, DUV, VIS, and IR wavelengths

    NASA Astrophysics Data System (ADS)

    Dumartin, Serge; Robert, Patrick; Hayer, Laurent

    2004-02-01

    Optical Components improvements generally call specific improvements of optical coatings. SESO introduce here, some examples of new coatings, developed for applications in its activity fields such as, space, defense, synchrotrons and high power laser programs, astronomy. To answer to a need of coating, in a very wide wavelength range, from X rays to FAR IR: - Metallic reflective coating for X Rays. - Specific Aluminium coating for EUV up to 190 nm - Dielectric coatings for wavelength broadband, double or triple bands (VIS + IR) To answer to a need of High Level Laser damage: - Hf/Metal coating (R and AR) to face energies up to 40J/cm2 To answer to a need of long lifetime for coatings submitted to stringent environmental conditions: - enhanced silver coating for astronomical mirrors - Hard Gold for Space applications - Protected aluminium for solar simulators To answer to a need of coating a large variety of substrates: - R and AR coatings on Silicium, ZnS, ZnSe, Ge, Saphyr... At least to answer to a need of high uniformity coatings and to realise coating on very large optical components, SESO recently installed a large coating machine able to work with optical components up to Φ 1100mm.

  13. Nano-enabled tribological thin film coatings: global patent scenario.

    PubMed

    Sivudu, Kurva S; Mahajan, Yashwant R; Joshi, Shrikant V

    2014-01-01

    The aim of this paper is to present current status and future prospects of nano-enabled tribological thin film coatings based on worldwide patent landscape analysis. The study also presents an overview of technological trends by carrying out state-of-the-art literature analysis, including survey of corporate websites. Nanostructured tribological coatings encompass a wide spectrum of nanoscale microstructures, including nanocrystalline, nanolayered, nano-multilayered, nanocomposite, nanogradient structures or their unique combinations, which are composed of single or multi-component phases. The distinct microstructural features of the coatings impart outstanding tribological properties combined with multifunctional attributes to the coated components. Their unique combination of remarkable properties make them ideal candidates for a wide range of applications in diverse fields such as cutting and metalworking tools, biomedical devices, automotive engine components, wear parts, hard disc drives etc. The patent landscape analysis has revealed that nano-enabled tribological thin film coatings have significant potential for commercial applications in view of the lion's share of corporate industry in patenting activity. The largest patent portfolio is held by Japan followed by USA, Germany, Sweden and China. The prominent players involved in this field are Mitsubishi Materials Corp., Sandvik Aktiebolag, Hitachi Ltd., Sumitomo Electric Industries Ltd., OC Oerlikon Corp., and so on. The outstanding potential of nanostructured thin film tribological coatings is yet to be fully unravelled and, therefore, immense opportunities are available in future for microstructurally engineered novel coatings to enhance their performance and functionality by many folds.

  14. Thermal barrier coating life prediction model development

    NASA Technical Reports Server (NTRS)

    Strangman, T. E.; Neumann, J. F.; Liu, A.

    1986-01-01

    Thermal barrier coatings (TBCs) for turbine airfoils in high-performance engines represent an advanced materials technology with both performance and durability benefits. The foremost TBC benefit is the reduction of heat transferred into air-cooled components, which yields performance and durability benefits. This program focuses on predicting the lives of two types of strain-tolerant and oxidation-resistant TBC systems that are produced by commercial coating suppliers to the gas turbine industry. The plasma-sprayed TBC system, composed of a low-pressure plasma-spray (LPPS) or an argon shrouded plasma-spray (ASPS) applied oxidation resistant NiCrAlY (or CoNiCrAlY) bond coating and an air-plasma-sprayed yttria (8 percent) partially stabilized zirconia insulative layer, is applied by Chromalloy, Klock, and Union Carbide. The second type of TBC is applied by the electron beam-physical vapor deposition (EB-PVD) process by Temescal.

  15. High-Temperature Solid Lubricant Coating

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Edmonds, Brian J.

    2010-01-01

    NASA PS400 is a solid lubricant coating invented for high-temperature tribological applications. This plasma-sprayed coating is a variant of the previously patented PS304 coating, and has been formulated to provide higher density, smoother surface finish, and better dimensional stability. This innovation is a new composite material that provides a means to reduce friction and wear in mechanical components. PS400 is a blend of a nickel-molybdenum binder, chrome oxide hardener, silver lubricant, and barium fluoride/calcium fluoride eutectic lubricant that can either be sprayed or deposited by other means, such as powder metallurgy. The resulting composite material is then finished by grinding and polishing to produce a smooth, self-lubricating surface.

  16. Delamination-Indicating Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Eldridge, Jeffrey I.

    2007-01-01

    The risk of premature failure of thermal barrier coatings (TBCs), typically composed of yttria-stabilized zirconia (YSZ), compromises the reliability of TBCs used to provide thermal protection for turbine engine components. Unfortunately, TBC delamination proceeds well beneath the TBC surface and cannot be monitored by visible inspection. Nondestructive diagnostic tools that could reliably probe the subsurface damage state of TBCs would alleviate the risk of TBC premature failure by indicating when the TBC needs to be replaced before the level of TBC damage threatens engine performance or safety. To meet this need, a new coating design for thermal barrier coatings (TBCs) that are self-indicating for delamination has been successfully implemented by incorporating a europium-doped luminescent sublayer at the base of a TBC composed of YSZ. The luminescent sublayer has the same YSZ composition as the rest of the TBC except for the addition of low-level europium doping and therefore does not alter TBC performance.

  17. Complete qualification methodology for coatings of precision glass molding tools

    NASA Astrophysics Data System (ADS)

    Klocke, Fritz; Georgiadis, Kyriakos; Dambon, Olaf; Bouzakis, Konstantinos Dionysios; Gerardis, Stefanos; Skordaris, Georgios

    2012-07-01

    Precision glass molding is the technology of choice for the production of complex-shaped optical components. Protective coatings can significantly extend the lifetime of the molding tools, but the coating properties have to be exactly customized for individual application conditions. The current biggest challenge is to ensure the reliability of newly developed coatings without resorting to extensive and expensive practical testing. However, the usual coating qualification methods either cannot be used or don't provide meaningful results. In this work a new three-tier, application-specific methodology for the qualification such coatings is presented. First, the basic characterization of coating properties is discussed, taking into account the specific characteristics of the coatings used for precision glass molding tools. In the second step, application-specific testing methods are devised, based on the analysis of the loads during glass molding. Finally, a new machine for testing the lifetime of the coated molding tools is proposed. Three case studies are presented where nanoscratch, nanoimpact and glass contact tests are performed with Pt-Ir, TiAlN, and CrAlN-coated samples in combination with various glass types, showcasing the usefulness of the proposed three-tier methodology.

  18. Electrospinning Yarn Formation and Coating

    NASA Astrophysics Data System (ADS)

    Sahbaee Bagherzadeh, Arash

    Electrospinning is a process by which nano polymer fibers can be produced using an electrostatically driven jet of polymer solution. Electrospinning seems to be a relatively simple process for producing nanofibers since it utilizes a few readily available components. On closer examination it is however clearly evident that successful electrospinning involves an understanding of the complex interaction of electrostatic fields, properties of polymer solutions and component design and system geometry. Using grounded plate as a collector causes the uniform electric field in all directions, so the electrostatic forces acting on the fiber have no preferential direction in the plane of the collector, results in a random deposition of the electrospun fibers leading to an isotropic web. For achieving their unique abilities to be useful in devices needs to deposit them in specific location and orientation. In this project a unique needle electrospinning process is described in which nanofibers are continuously fabricated, uniaxially oriented, and twisted to form of a yarn. It is shown that perfectly aligned nanofiber assemblies can be generated by manipulating the electric field. Twist insertion is accomplished by using two stepper motors and associated software. ANSYS/Emag.3-D is used to model the path of the electric field between the needle and the collector and the electrostatic forces acting on a charged nanofiber. The apparatus described, appears to offer advantages over other techniques. Nanofibers need not only be used as webs or yarn in order to attain the performance enhancement of high tech applications, but it is possible to introduce the benefit of nanofiber to regular yarn and other materials, by coating with nanofibers An addition advantage of the present setup is that it is possible to produce continuous fiber hybrid yarn coated with aligned nanofibers along the core yarn axis. With this method it is not only possible to coat regular yarn with aligned

  19. Isomolybdate conversion coatings

    NASA Technical Reports Server (NTRS)

    Minevski, Zoran (Inventor); Maxey, Jason (Inventor); Nelson, Carl (Inventor); Eylem, Cahit (Inventor)

    2002-01-01

    A conversion coating solution and process forms a stable and corrosion-resistant layer on metal substrates or layers or, more preferably, on a boehmite layer or other base conversion coating. The conversion coating process involves contacting the substrate, layer or coating with an aqueous alkali metal isomolybdate solution in order to convert the surface of the substrate, layer or coating to a stable conversion coating. The aqueous alkali metal molybdates are selected from sodium molybdate (Na.sub.2 MoO.sub.4), lithium molybdate (Li.sub.2 MoO.sub.4), potassium molybdate (K.sub.2 MoO.sub.4), or combinations thereof, with the most preferred alkali metal molybdate being sodium molybdate. The concentration of alkali metal molybdates in the solution is preferably less than 5% by weight. In addition to the alkali metal molybdates, the conversion coating solution may include alkaline metal passivators selected from lithium nitrate (LiNO.sub.3), sodium nitrate (NaNO.sub.3), ammonia nitrate (NH.sub.4 NO.sub.3), and combinations thereof; lithium chloride, potassium hexafluorozirconate (K.sub.2 ZrF.sub.6) or potassium hexafluorotitanate (K.sub.2 TiF.sub.6).

  20. Phenol-formaldehyde intumescent coating composition and coating prepared therefrom

    NASA Technical Reports Server (NTRS)

    Salyer, Ival O. (Inventor); Fox, Bernard L. (Inventor)

    1986-01-01

    Intumescent coatings which form a thick, uniform, fine celled, low density foam upon exposure to a high intensity heat flux or flame are disclosed, the invention coatings comprise phenolic resin prepolymer containing a blowing agent and a nucleating agent; in the preferred embodiments the coatings also contains a silicone surfactant, the coatings are useful in thermal and fire protection systems.

  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. The Development of Erosion and Impact Resistant Turbine Airfoil Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    2007-01-01

    Thermal barrier coatings are used in gas turbine engines to protect engine hot-section components in the harsh combustion environments and extend component lifetimes. For thermal barrier coatings designed for turbine airfoil applications, further improved erosion and impact resistance are crucial for engine performance and durability. Advanced erosion resistant thermal barrier coatings are being developed, with a current emphasis on the toughness improvements using a combined rare earth- and transition metal-oxide doping approach. The performance of the doped thermal barrier coatings has been evaluated in burner rig and laser heat-flux rig simulated engine erosion and thermal gradient environments. The results have shown that the coating composition optimizations can effectively improve the erosion and impact resistance of the coating systems, while maintaining low thermal conductivity and cyclic durability. The erosion and impact damage mechanisms of the thermal barrier coatings will also be discussed.

  3. Coating system to permit direct brazing of ceramics

    DOEpatents

    Cadden, Charles H.; Hosking, F. Michael

    2003-01-01

    This invention relates to a method for preparing the surface of a ceramic component that enables direct brazing using a non-active braze alloy. The present invention also relates to a method for directly brazing a ceramic component to a ceramic or metal member using this method of surface preparation, and to articles produced by using this brazing method. The ceramic can be high purity alumina. The method comprises applying a first coating of a silicon-bearing oxide material (e.g. silicon dioxide or mullite (3Al.sub.2 O.sub.3.2SiO.sub.2) to the ceramic. Next, a thin coating of active metal (e.g. Ti or V) is applied. Finally, a thicker coating of a non-active metal (e.g. Au or Cu) is applied. The coatings can be applied by physical vapor deposition (PVD). Alternatively, the active and non-active metals can be co-deposited (e.g. by sputtering a target made of mullite). After all of the coatings have been applied, the ceramic can be fired at a high temperature in a non-oxidizing environment to promote diffusion, and to enhance bonding of the coatings to the substrate. After firing, the metallized ceramic component can be brazed to other components using a conventional non-active braze alloy. Alternatively, the firing and brazing steps can be combined into a single step. This process can replace the need to perform a "moly-manganese" metallization step.

  4. Chrome Free Coatings for Fasteners and Metal Components

    DTIC Science & Technology

    2010-06-01

    DX551810 Delphi DX45501804 Fiat 9.57513/Tipo IV Ford S439 (WSS-M21P37-A1) Automotive Company Specification Number General Motors GM7114M General Motors ...GMW3359 Land Rover LRES.21.ZS.05 Nissan NES M4601 Porsche PTL 7529 PSA B15 3320 Renault Truck 01.71.4002/H TRW TS 2-25-60, Class A Volkswagen TL233 Volvo

  5. Nano powders, components and coatings by plasma technique

    DOEpatents

    McKechnie, Timothy N.; Antony, Leo V. M.; O'Dell, Scott; Power, Chris; Tabor, Terry

    2009-11-10

    Ultra fine and nanometer powders and a method of producing same are provided, preferably refractory metal and ceramic nanopowders. When certain precursors are injected into the plasma flame in a reactor chamber, the materials are heated, melted and vaporized and the chemical reaction is induced in the vapor phase. The vapor phase is quenched rapidly to solid phase to yield the ultra pure, ultra fine and nano product. With this technique, powders have been made 20 nanometers in size in a system capable of a bulk production rate of more than 10 lbs/hr. The process is particularly applicable to tungsten, molybdenum, rhenium, tungsten carbide, molybdenum carbide and other related materials.

  6. Nano powders, components and coatings by plasma technique

    NASA Technical Reports Server (NTRS)

    McKechnie, Timothy N. (Inventor); Antony, Leo V. M. (Inventor); O'Dell, Scott (Inventor); Power, Chris (Inventor); Tabor, Terry (Inventor)

    2009-01-01

    Ultra fine and nanometer powders and a method of producing same are provided, preferably refractory metal and ceramic nanopowders. When certain precursors are injected into the plasma flame in a reactor chamber, the materials are heated, melted and vaporized and the chemical reaction is induced in the vapor phase. The vapor phase is quenched rapidly to solid phase to yield the ultra pure, ultra fine and nano product. With this technique, powders have been made 20 nanometers in size in a system capable of a bulk production rate of more than 10 lbs/hr. The process is particularly applicable to tungsten, molybdenum, rhenium, tungsten carbide, molybdenum carbide and other related materials.

  7. COATING URANIUM FROM CARBONYLS

    DOEpatents

    Gurinsky, D.H.; Storrs, S.S.

    1959-07-14

    Methods are described for making adherent corrosion resistant coatings on uranium metal. According to the invention, the uranium metal is heated in the presence of an organometallic compound such as the carbonyls of nickel, molybdenum, chromium, niobium, and tungsten at a temperature sufficient to decompose the metal carbonyl and dry plate the resultant free metal on the surface of the uranium metal body. The metal coated body is then further heated at a higher temperature to thermally diffuse the coating metal within the uranium bcdy.

  8. A Multifunctional Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Hintze, Paul E.; Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott T.

    2010-01-01

    Corrosion is a destructive process that often causes failure in metallic components and structures. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to control it. The multi-functionality of the coating is based on microencapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of other existing microcapsules designs, the corrosion controlled release function that allows the delivery of corrosion indicators and inhibitors on demand only when and where they are needed. Corrosion indicators as well as corrosion inhibitors have been incorporated into the microcapsules, blended into several paint systems, and tested for corrosion detection and protection efficacy.

  9. Thermal barrier coating life prediction model development

    NASA Technical Reports Server (NTRS)

    Demasi, J. T.

    1986-01-01

    A methodology is established to predict thermal barrier coating life in a environment similar to that experienced by gas turbine airfoils. Experiments were conducted to determine failure modes of the thermal barrier coating. Analytical studies were employed to derive a life prediction model. A review of experimental and flight service components as well as laboratory post evaluations indicates that the predominant mode of TBC failure involves thermomechanical spallation of the ceramic coating layer. This ceramic spallation involves the formation of a dominant crack in the ceramic coating parallel to and closely adjacent to the topologically complex metal ceramic interface. This mechanical failure mode clearly is influenced by thermal exposure effects as shown in experiments conducted to study thermal pre-exposure and thermal cycle-rate effects. The preliminary life prediction model developed focuses on the two major damage modes identified in the critical experiments tasks. The first of these involves a mechanical driving force, resulting from cyclic strains and stresses caused by thermally induced and externally imposed mechanical loads. The second is an environmental driving force based on experimental results, and is believed to be related to bond coat oxidation. It is also believed that the growth of this oxide scale influences the intensity of the mechanical driving force.

  10. Environmental Barrier Coatings for Ceramic Matrix Composites - An Overview

    NASA Technical Reports Server (NTRS)

    Lee, Kang; Zhu, Dongming; Wiesner, Valerie Lynn; van Roode, Mark; Kashyap, Tania; Zhu, Dongming; Wiesner, Valerie

    2016-01-01

    Ceramic Matrix Composites (CMCs) are increasingly being considered as structural materials for advanced power generation equipment. Broadly speaking the two classes of materials are oxide-based CMCs and non-oxide based CMCs. The non-oxide CMCs are primarily silicon-based. Under conditions prevalent in the gas turbine hot section the water vapor formed in the combustion of gaseous or liquid hydrocarbons reacts with the surface-SiO2 to form volatile products. Progressive surface recession of the SiC-SiC CMC component, strength loss as a result of wall thinning and chemical changes in the component occur, which leads to the loss of structural integrity and mechanical strength and becomes life limiting to the equipment in service. The solutions pursued to improve the life of SiC-SiC CMCs include the incorporation of an external barrier coating to provide surface protection to the CMC substrate. The coating system has become known as an Environmental Barrier Coating (EBC). The relevant early coatings work was focused on coatings for corrosion protection of silicon-based monolithic ceramics operating under severely corrosive conditions. The development of EBCs for gas turbine hot section components was built on the early work for silicon-based monolithics. The first generation EBC is a three-layer coating, which in its simplest configuration consists of a silicon (Si) base coat applied on top of the CMC, a barium-strontium-aluminosilicate (BSAS) surface coat resistant to water vapor attack, and a mullite-based intermediate coating layer between the Si base coat and BSAS top coat. This system can be represented as Si-Mullite-BSAS. While this baseline EBC presented a significant improvement over the uncoated SiC-SiC CMC, for the very long durations of 3-4 years or more expected for industrial operation further improvements in coating durability are desirable. Also, for very demanding applications with higher component temperatures but shorter service lives more rugged EBCs

  11. Plasma membrane coat and a coated vesicle-associated reticulum of membranes: their structure and possible interrelationship in Chara corallina

    PubMed Central

    1984-01-01

    Primary fixation with buffered glutaraldehyde plus 2.0 mM CaCl2 and 0.1% tannic acid results in the preservation of certain portions of the plasma membrane coat of Chara when seen with the electron microscope. Such a coat is not observable after fixation with glutaraldehyde alone. The coat appears to be present on all the above ground, vegetative cells of the male plant. Within complex invaginations of the plasma membrane, which are known as charasomes, the coat has two structural components, a central core that is either tubular or solid and a fibrous or granular peripheral region that surrounds the core. The coat material appears to be at least partially derived, via exocytosis, from the contents of single membrane-bound organelles known as glycosomes. Glycosomes seem to originate from within an assemblage of membranes and coated vesicles that can be described, in purely structural terms, as a partially coated reticulum. Such a reticulum is distinguishable from Golgi stacks because the reticulum (a) is not composed of stacked membranes, (b) is extensively involved with large, clearly detailed coated vesicles and coated invaginations, (c) is closely associated with glycosomes, and (d) is only slightly stained by the zinc-iodide- osmium tetraoxide reagent. PMID:6425304

  12. Hybrid glass coatings for optical fibers: effect of coating thickness on strength and dynamic fatigue characteristics of silica fibers

    NASA Astrophysics Data System (ADS)

    Wojcik, A. B.; Matthewson, M. J.; Castelino, K. T.; Wojcik, J.; Walewski, A.

    2006-04-01

    Specialty optical fibers operating in harsh aerospace environments are typically exposed to high temperatures and elevated humidity. This calls for better performing protective coatings. Recently developed sol-gel derived inorganicorganic hybrid materials called hybrid glass offered improved protective performance as compared to standard dual polymer coated fibers [1]. In this paper we examine the effectiveness of online UV curing for the protective ability of hybrid glass coatings. For this purpose two types of UV-curable hybrid glass candidates representing two different concentrations of acrylate groups were applied online to silica fibers as single and dual coats. Samples of fibers were collected and subjected to dynamic fatigue testing by two-point bending. The stress corrosion parameter, n, as well as the strength of the fibers were determined. Both the strength and n were higher for fibers with two layers of coating as compared to single coatings even when the thickness of both one and two layer coatings was the same. This may be caused by the greater degree of cross linking of the inorganic component when the coating is exposed twice to the heat generated in the UV chamber. Coating materials with reduced acrylate group content had higher values of the fatigue parameter n but at the same time reduced strength.

  13. Characterization of thermally sprayed coatings for high-temperature wear-protection applications

    SciTech Connect

    Li, C.C.

    1980-03-01

    Under normal high-temperature gas-cooled reactor (HTGR) operating conditions, faying surfaces of metallic components under high contact pressure are prone to friction, wear, and self-welding damage. Component design calls for coatings for the protection of the mating surfaces. Anticipated operating temperatures up to 850 to 950/sup 0/C (1562 to 1742/sup 0/F) and a 40-y design life require coatings with excellent thermal stability and adequate wear and spallation resistance, and they must be compatible with the HTGR coolant helium environment. Plasma and detonation-gun (D-gun) deposited chromium carbide-base and stabilized zirconia coatings are under consideration for wear protection of reactor components such as the thermal barrier, heat exchangers, control rods, and turbomachinery. Programs are under way to address the structural integrity, helium compatibility, and tribological behavior of relevant sprayed coatings. In this paper, the need for protection of critical metallic components and the criteria for selection of coatings are discussed. The technical background to coating development and the experience with the steam cycle HTGR (HTGR-SC) are commented upon. Coating characterization techniques employed at General Atomic Company (GA) are presented, and the progress of the experimental programs is briefly reviewed. In characterizing the coatings for HTGR applications, it is concluded that a systems approach to establish correlation between coating process parameters and coating microstructural and tribological properties for design consideration is required.

  14. Application of scanning sampling for studying coatings

    NASA Astrophysics Data System (ADS)

    Surmenko, Elena L.; Tuchin, Valery V.; Sokolova, Tatiana N.; Konyushin, Alexander V.; Chebotarevsky, Yury V.

    2005-04-01

    LIBS is one of the best methods of multilayer coatings studying. Special laser technique-scanning sampling-was developed for studying of different kinds of objects (technical and biomedical coatings). The scanning sampling is based on the scanning of analyzed object during the exposition time. The velocity of scanning is defined by the diameter of laser crater and pulse repetition rate. It allows to increase the volume part of a coating substance in a sample. Some special applications of LIBS and scanning sampling with Q-switched Nd:YAG-laser in the field of technics and biomedicine are described. The layer-by-layer elemental analysis of multilayer components was performed for finding-out the probable non-uniformity. That could appear the reason of wrong work of components. Special layer characteristic calculated as a ratio of spectral lines intensities for elements contained in different layers of a coating was defined for estimation non-uniformity. LIBS in investigation of dental tissues allows to define preliminary the nature of pathology. Scanning sampling used for such tissues as debris and odontolith, allows to find out the stage of lesion and to predict carious conditions.

  15. Method of fluxless brazing and diffusion bonding of aluminum containing components

    NASA Technical Reports Server (NTRS)

    Featherston, A. B.; Okelly, K. P. (Inventor)

    1976-01-01

    A method of diffusion bonding and fluxless brazing of aluminum containing components is reported. The aluminum surfaces are freed of any aluminum oxide coating and are coated with a polymeric sealer which can be thermally removed leaving essentially no residue. The polymeric sealer is being removed in a substantially oxygen free environment, and the aluminum components are then being brazed or diffusion bonded without the use of a flux to remove oxide coating.

  16. An organic chromium-free conversion coating on AZ91D magnesium alloy

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoming; Li, Guangyu; Lian, Jianshe; Jiang, Qing

    2008-12-01

    Traditional conversion coatings on magnesium alloys are usually immersed in a solution containing hexavalent chromium compounds. However, the replacement treatments have been proposed by the present environmental driving to eliminate hexavalent chromium. In this work, a tannic acid based conversion coating on AZ91D magnesium alloy was obtained by treatment in a solution containing tannic acid and ammonium metavanadate. SEM, XPS and IR were used to determine the morphology and structure of the conversion coatings. Continuous and uniform conversion coating was deposited on AZ91D alloy and the main components of the coatings were Al 2O 3, MgF 2 and penta-hydroxy benzamide-magnesium complex. The formation mechanism of the coating was discussed. Polarization measurement and salt spray test showed that the corrosion resistance of the conversion coating was much higher than that of traditional chromate conversion coating.

  17. Plasma-sprayed coatings for lubrication of a titanium alloy in air at 430 deg C

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.; Wisander, D. H.

    1979-01-01

    Plasma sprayed coatings of pure silver and of composite materials containing silver were investigated as possible self lubricating coatings for titanium alloys in air at 430 C. Pure silver provided low friction but was prone to severe plastic deformation and excessive transfer except in coating thicknesses of 0.02 mm or less. Additions of nichrome, calcium fluoride, and glass to silver were all beneficial in reducing plastic deformation and otherwise improving the coatings. The longest coating wear life, low wear of Ti alloy pins in sliding contact with the coatings, and a steady friction coefficient of 0.19 were obtained with a four component coating of 0.17 mm thickness. The coating composition, in weight percent is 30 nichrome-30 Ag-25 CaF2-15 glass.

  18. In vitro evaluation of coating polymers for enteric coating and human ileal targeting.

    PubMed

    Huyghebaert, Nathalie; Vermeire, An; Remon, Jean Paul

    2005-07-14

    Recombinant interleukin-10 producing Lactococcus lactis is an alternative therapy for Crohn's disease. For in vivo interleukin-10 production, thymidine, the essential feed component of these recombinant bacteria should be coadministered. Different coating polymers were evaluated in vitro for enteric properties and targeting suitability to the ileum, the major site of inflammation in Crohn's disease. To guarantee ileal delivery, the polymer must dissolve from pH 6.8 and allow complete release within 40 min. Aqoat AS-HF coated pellets (15%) showed poor enteric properties and thymidine was released below pH 6.8. Eudragit FS30D coated pellets (15%) showed good enteric properties, but no thymidine was released within 40 min at pH 6.8. Eudragit S coated pellets (15%) showed good enteric properties after curing at elevated temperature while no thymidine was released within 40 min at pH 6.8. In another approach to pass the proximal small intestine intact, pellets were coated with 30% Eudragit L30D-55. At pH 6.0, they showed a lag-phase of 20 min. No influence of layer thickness was seen above pH 6.5. Alternatively, pellets were coated with a mixture of Eudragit FS30D/L30D-55 but they showed poor enteric properties and thymidine was released below pH 6.8. In conclusion, none of the tested polymers/mixtures ensured enteric properties and ileal targeting.

  19. Survey of material for an infrared-opaque coating

    NASA Technical Reports Server (NTRS)

    Smith, Sheldon M.; Howitt, Richard V.

    1986-01-01

    More than 40 reflectance spectra in the range from 20 to 500 microns have been obtained of a variety of coatings, binders, and additives to identify promising components of an infrared-opaque coating for the Space Infrared Telescope Facility. Certain combinations of materials showed a specular reflectance below 0.1 throughout the spectral range measured. In addition to estimating the optical constants of several combination coatings, this survey also supports three qualitative conclusions: (1) promising 'off-the-shelf' binders of different additives are Chemglaze Z-306, ECP-2200, and De Soto Black; (2) carbon black is very effective reducing far-infrared reflectance; and (3) the far-infrared reflectance from coatings containing 80 SiC grit is consistently lower than that from similar coatings containing TlBr powder.

  20. Survey of Material for an Infrared-Opaque Coating

    NASA Technical Reports Server (NTRS)

    Smith, Sheldon M.; Howitt, Richard V.

    1986-01-01

    More than 40 reflectance spectra in the range from 20 to 500 microns have been obtained for a variety of coatings, binders, and additives to identify promising components of an infrared-opaque coating for the Space Infrared Telescope Facility. Certain combinations of materials showed a specular reflectance below 0.1 throughout the spectral range measured. In addition to estimating the optical constants of several combination coatings, this survey also supports three qualitative conclusions: (1) promising off-the-shelf binders of different additives are Chemglaze Z-306, ECP-2200, and De Soto Black; (2) carbon black is very effective in reducing far-infrared reflectance; (3) the far-infrared reflectance from coatings containing 80 SiC grit is consistently lower than that from similar coatings containing TiBr powder.

  1. Modeling Oxidation Induced Stresses in Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Ferguson, B. L.; Freborg, A. M.; Petrus, G. J.; Brindley, William J.

    1998-01-01

    The use of thermal barrier coatings (TBC's) in gas turbines has increased dramatically in recent years, due mainly to the need for component protection from ever increasing service temperatures. Oxidation of the bond coat has been identified as an important contributing factor to spallation of the ceramic top coat during service. Additional variables found to influence TBC thermal cycle life include bond coat coefficient of thermal expansion, creep behavior of both the ceramic and bond coat layers, and modulus of elasticity. The purpose of this work was to characterize the effects of oxidation on the stress states within the TBC system, as well as to examine the interaction of oxidation with other factors affecting TBC life.

  2. POWDER COAT APPLICATIONS

    EPA Science Inventory

    The report discusses an investigation of critical factors that affect the use of powder coatings on the environment, cost, quality, and production. The investigation involved a small business representative working with the National Defense Center for Environmental Excellence (ND...

  3. 'Mazatzal's' Many Coats

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This close-up image taken by the Mars Exploration Rover Spirit's microscopic imager shows a section of the hole drilled into the rock dubbed 'Mazatzal' after the hole was ground for a second time. The first drilling by the rover's rock abrasion tool left an incomplete hole, so a second one was performed. The blue arrow points to leftover portions of the dark rind that coats Mazatzal and the scrape marks left by the rock abrasion tool. The yellow arrow highlights the bright edges surrounding the leftover rind. The crack in the rock may have once contained fluids out of which minerals precipitated along its walls (red arrows). Mazatzal is a highly coated rock, containing at least four 'cake layers': a top coat of dust, a pinking coating, a dark rind and its true interior. The observed area is 3 centimeters (1.2 inches) across. This image was taken on sol 85.

  4. Aluminum phosphate coatings

    DOEpatents

    Sambasivan, Sankar; Steiner, Kimberly A.; Rangan, Krishnaswamy K.

    2007-12-25

    Aluminophosphate compounds and compositions as can be used for substrate or composite films and coating to provide or enhance, without limitation, planarization, anti-biofouling and/or anti-microbial properties.

  5. 'Mazatzal's' Many Coats

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This close-up image taken by the Mars Exploration Rover Spirit's microscopic imager shows a section of the hole drilled into the rock dubbed 'Mazatzal' after the hole was ground for a second time. The first drilling by the rover's rock abrasion tool left an incomplete hole, so a second one was performed. The blue arrow points to leftover portions of the dark rind that coats Mazatzal and the scrape marks left by the rock abrasion tool. The yellow arrow highlights the bright edges surrounding the leftover rind. The crack in the rock may have once contained fluids out of which minerals precipitated along its walls (red arrows). Mazatzal is a highly coated rock, containing at least four 'cake layers': a top coat of dust, a pinking coating, a dark rind and its true interior. The observed area is 3 centimeters (1.2 inches) across. This image was taken on sol 85.

  6. Multilayer optical dielectric coating

    DOEpatents

    Emmett, John L.

    1990-01-01

    A highly damage resistant, multilayer, optical reflective coating includes alternating layers of doped and undoped dielectric material. The doping levels are low enough that there are no distinct interfaces between the doped and undoped layers so that the coating has properties nearly identical to the undoped material. The coating is fabricated at high temperature with plasma-assisted chemical vapor deposition techniques to eliminate defects, reduce energy-absorption sites, and maintain proper chemical stoichiometry. A number of differently-doped layer pairs, each layer having a thickness equal to one-quarter of a predetermined wavelength in the material are combined to form a narrowband reflective coating for a predetermined wavelength. Broadband reflectors are made by using a number of narrowband reflectors, each covering a portion of the broadband.

  7. POWDER COAT APPLICATIONS

    EPA Science Inventory

    The report discusses an investigation of critical factors that affect the use of powder coatings on the environment, cost, quality, and production. The investigation involved a small business representative working with the National Defense Center for Environmental Excellence (ND...

  8. Preventing Cracking of Anodized Coatings

    NASA Technical Reports Server (NTRS)

    He, Charles C.; Heslin, Thomas M.

    1995-01-01

    Anodized coatings have been used as optical and thermal surfaces in spacecraft. Particulate contamination from cracked coatings is a concern for many applications. The major cause for the cracking is the difference in the coefficient of thermal expansion between the oxide coatings and the aluminum substrate. The loss of water when the coating is exposed to a vacuum also could induce cracking of the coating. Hot-water sealing was identified as the major cause for the cracking of the coatings because of the large temperature change when the parts were immersed in boiling water and the water was absorbed in the coating. when the hot-water sealing process was eliminated, the cracking resistance of the anodized coatings was greatly improved. Also, it was found that dyed black coatings were more susceptible than clear coatings to cracking during thermo-vacuum cyclings.

  9. Friction surfaced Stellite6 coatings

    SciTech Connect

    Rao, K. Prasad; Damodaram, R.; Rafi, H. Khalid; Ram, G.D. Janaki; Reddy, G. Madhusudhan; Nagalakshmi, R.

    2012-08-15

    Solid state Stellite6 coatings were deposited on steel substrate by friction surfacing and compared with Stellite6 cast rod and coatings deposited by gas tungsten arc and plasma transferred arc welding processes. Friction surfaced coatings exhibited finer and uniformly distributed carbides and were characterized by the absence of solidification structure and compositional homogeneity compared to cast rod, gas tungsten arc and plasma transferred coatings. Friction surfaced coating showed relatively higher hardness. X-ray diffraction of samples showed only face centered cubic Co peaks while cold worked coating showed hexagonally close packed Co also. - Highlights: Black-Right-Pointing-Pointer Stellite6 used as coating material for friction surfacing. Black-Right-Pointing-Pointer Friction surfaced (FS) coatings compared with casting, GTA and PTA processes. Black-Right-Pointing-Pointer Finer and uniformly distributed carbides in friction surfaced coatings. Black-Right-Pointing-Pointer Absence of melting results compositional homogeneity in FS Stellite6 coatings.

  10. Spin coating apparatus

    DOEpatents

    Torczynski, John R.

    2000-01-01

    A spin coating apparatus requires less cleanroom air flow than prior spin coating apparatus to minimize cleanroom contamination. A shaped exhaust duct from the spin coater maintains process quality while requiring reduced cleanroom air flow. The exhaust duct can decrease in cross section as it extends from the wafer, minimizing eddy formation. The exhaust duct can conform to entrainment streamlines to minimize eddy formation and reduce interprocess contamination at minimal cleanroom air flow rates.

  11. Ceramic electrolyte coating methods

    DOEpatents

    Seabaugh, Matthew M.; Swartz, Scott L.; Dawson, William J.; McCormick, Buddy E.

    2004-10-12

    Processes for preparing aqueous suspensions of a nanoscale ceramic electrolyte material such as yttrium-stabilized zirconia. The invention also includes a process for preparing an aqueous coating slurry of a nanoscale ceramic electrolyte material. The invention further includes a process for depositing an aqueous spray coating slurry including a ceramic electrolyte material on pre-sintered, partially sintered, and unsintered ceramic substrates and products made by this process.

  12. METAL COATING BATHS

    DOEpatents

    Robinson, J.W.

    1958-08-26

    A method is presented for restoring the effectiveness of bronze coating baths used for hot dip coating of uranium. Such baths, containing a high proportion of copper, lose their ability to wet uranium surfaces after a period of use. The ability of such a bath to wet uranium can be restored by adding a small amount of metallic aluminum to the bath, and skimming the resultant hard alloy from the surface.

  13. Materials Coating Techniques

    DTIC Science & Technology

    1980-03-01

    properties of the coating layers and their interaction with the bulk material will be considered. Lectures will also cover the behaviour of coated parts...stability etc. Finally, available techniques for the analysis and non-destructive evaluation of the composition. properties and soundness of the...provide stiffness or flexibility, and to carry the applied loads without macroscopic failure. Such properties are associated with the bulk material of

  14. Nanostructured Superhydrophobic Coatings

    SciTech Connect

    2009-03-01

    This factsheet describes a research project that deals with the nanostructured superhydrophobic (SH) powders developed at ORNL. This project seeks to (1) improve powder quality; (2) identify binders for plastics, fiberglass, metal (steel being the first priority), wood, and other products such as rubber and shingles; (3) test the coated product for coating quality and durability under operating conditions; and (4) application testing and production of powders in quantity.

  15. Advanced Environmental Barrier Coatings Development for Si-Based Ceramics

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Choi, R. Sung; Robinson, Raymond C.; Lee, Kang N.; Bhatt, Ramakrishna T.; Miller, Robert A.

    2005-01-01

    Advanced environmental barrier coating concepts based on multi-component HfO2 (ZrO2) and modified mullite systems are developed for monolithic Si3N4 and SiC/SiC ceramic matrix composite (CMC) applications. Comprehensive testing approaches were established using the water vapor cyclic furnace, high pressure burner rig and laser heat flux steam rig to evaluate the coating water vapor stability, cyclic durability, radiation and erosion resistance under simulated engine environments. Test results demonstrated the feasibility and durability of the environmental barrier coating systems for 2700 to 3000 F monolithic Si3N4 and SiC/SiC CMC component applications. The high-temperature-capable environmental barrier coating systems are being further developed and optimized in collaboration with engine companies for advanced turbine engine applications.

  16. A supercritical fluid-based coating technology. 2: solubility considerations.

    PubMed

    Ribeiro Dos Santos, I; Thies, C; Richard, J; Le Meurlay, D; Gajan, V; VandeVelde, V; Benoit, J-P

    2003-01-01

    Solubility measurements of candidate coating materials have been performed in supercritical (SC) CO(2) so as to select appropriate coating materials for implementation of a solvent-free coating process previously described. Solubility of lipidic compounds such as waxes (paraffin, beeswax, Carnauba wax), pure triglycerides (tricaprin, trimyristin, tripalmitin, tristearin) and mixture of glycerides and fatty acid esters (Gelucire) in SC CO(2) were evaluated in a static mode under different temperature and pressure conditions, ranging from 13-52 degrees C and from 50-220 bar, whether the CO(2)was in its liquid or SC state. It was shown that the compounds which are mixtures of various components give rise to a selective extraction of the lower melting point components, as evidenced from thermal analysis of soluble and insoluble fractions of the coating materials.

  17. A final look at LDEF electro-optic systems components

    NASA Technical Reports Server (NTRS)

    Blue, M. D.

    1995-01-01

    Postrecovery characteristics of LDEF electro-optic components from the GTRI tray are compared with their prelaunch characteristics and with the characteristics of similar components from related experiments. Components considered here include lasers, light-emitting diodes, semiconducting radiation detectors and arrays, optical substrates, filters, and mirrors, and specialized coatings. Our understanding of the physical effects resulting from low earth orbit are described, and guidelines and recommendations for component and materials choices are presented.

  18. Therma1 Conductivity and Durability of Advanced Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Miller, Robert A.

    2003-01-01

    Thermal barrier coatings (TBCs) will play a crucial role in advanced gas turbine engines because of their ability to further increase engine operating temperature and reduce cooling, thus helping to achieve engine emission and efficiency goals. Future TBCs must be designed with increased phase stability, lower thermal conductivity, and improved sintering and thermal stress resistance in order to effectively protect engine hot-section components. Advanced low conductivity TBCs are being developed at NASA by incorporating multi-component oxide dopants into zirconia-yttria or hafnia-yttria to promote the formation of thermodynamically stable defect clusters within the coating structures. This presentation will primarily focus on thermal conductivity and durability of the novel defect cluster thermal barrier coatings for turbine airfoil and combustor applications, determined by a unique CO2 laser heat-flux approach. The laser heat-flux testing approach emphasizes the real-time monitoring and assessment of the coating thermal conductivity under simulated engine temperature and thermal gradient conditions. The conductivity increase due to coating sintering (and/or phase change) and the conductivity decrease due to coating delamination have been determined under steady-state, cyclic, uniform or non-uniform heat-flux conditions. The coating radiation flux resistance has been evaluated by varying coating thermal gradients, and also by using a laser-heated radiative-flux source. Advanced multi-component TBC systems have been shown to have significantly reduced thermal conductivity and improved high temperature stability due to the nano-sized, low mobility defect clusters associated with the paired rare earth dopant additions. The effect of oxide defect cluster dopants on coating thermal conductivity, thermal stability and furnace cyclic durability will also be discussed. The current low conductivity TBC systems have demonstrated long-term cyclic durability at very high

  19. Therma1 Conductivity and Durability of Advanced Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Miller, Robert A.

    2003-01-01

    Thermal barrier coatings (TBCs) will play a crucial role in advanced gas turbine engines because of their ability to further increase engine operating temperature and reduce cooling, thus helping to achieve engine emission and efficiency goals. Future TBCs must be designed with increased phase stability, lower thermal conductivity, and improved sintering and thermal stress resistance in order to effectively protect engine hot-section components. Advanced low conductivity TBCs are being developed at NASA by incorporating multi-component oxide dopants into zirconia-yttria or hafnia-yttria to promote the formation of thermodynamically stable defect clusters within the coating structures. This presentation will primarily focus on thermal conductivity and durability of the novel defect cluster thermal barrier coatings for turbine airfoil and combustor applications, determined by a unique CO2 laser heat-flux approach. The laser heat-flux testing approach emphasizes the real-time monitoring and assessment of the coating thermal conductivity under simulated engine temperature and thermal gradient conditions. The conductivity increase due to coating sintering (and/or phase change) and the conductivity decrease due to coating delamination have been determined under steady-state, cyclic, uniform or non-uniform heat-flux conditions. The coating radiation flux resistance has been evaluated by varying coating thermal gradients, and also by using a laser-heated radiative-flux source. Advanced multi-component TBC systems have been shown to have significantly reduced thermal conductivity and improved high temperature stability due to the nano-sized, low mobility defect clusters associated with the paired rare earth dopant additions. The effect of oxide defect cluster dopants on coating thermal conductivity, thermal stability and furnace cyclic durability will also be discussed. The current low conductivity TBC systems have demonstrated long-term cyclic durability at very high

  20. Multilayer thermal barrier coating systems

    DOEpatents

    Vance, Steven J.; Goedjen, John G.; Sabol, Stephen M.; Sloan, Kelly M.

    2000-01-01

    The present invention generally describes multilayer thermal barrier coating systems and methods of making the multilayer thermal barrier coating systems. The thermal barrier coating systems comprise a first ceramic layer, a second ceramic layer, a thermally grown oxide layer, a metallic bond coating layer and a substrate. The thermal barrier coating systems have improved high temperature thermal and chemical stability for use in gas turbine applications.

  1. Thin Film Optical Coatings

    NASA Astrophysics Data System (ADS)

    Ristau, Detlev; Ehlers, Henrik

    Within the scientific conception of the modern world, thin film optical coatings can be interpreted as one-dimensional photonic crystals. In general, they are composed of a sequence of single layers which consist of different transparent dielectrics with a thickness in the nanometer scale according to the operation wavelength range. The major function of these photonic structures is to adapt the properties of an optical surface to the needs of specific applications. By application of optical thin film coatings with optimized designs, the spectral characteristics of a surface can be modified to practically any required transfer function for a certain wavelength range. For example, the Fresnel reflection of a lens or a laser window can be suppressed for a broad wavelength range by depositing an antireflective coating containing only a few single layers. On the basis of a layer stack with alternating high- and low-refracting materials, high reflectance values up to 99.999% can be achieved for a certain laser wavelength. In addition to these basic functions, optical coatings can realize a broad variety of spectral filter characteristics according to even extremely sophisticated demands in modern precision optics and laser technology. Moreover, recent developments in optical thin film technology provide the means to combine selected optical properties with other features concerning, for instance, the thermal, mechanical or chemical stability of a surface. The latest progress in ophthalmic coatings even includes the integration of self-cleaning, photoactive or anti-fogging functions in antireflective coatings on glass.

  2. Bond Coating Performance of Thermal Barrier Coatings for Industrial Gas Turbines

    SciTech Connect

    Wright, Ian G; Pint, Bruce A

    2005-01-01

    Thermal barrier coatings are intended to work in conjunction with internal cooling schemes to reduce the metal temperature of critical hot gas path components in gas turbine engines. The thermal resistance is typically provided by a 100--250 {mu}m thick layer of ceramic (most usually zirconia stabilized with an addition of 7--8 wt% of yttria), and this is deposited on to an approximately 50 {mu} thick, metallic bond coating that is intended to anchor the ceramic to the metallic surface, to provide some degree of mechanical compliance, and to act as a reservoir of protective scale-forming elements (Al) to protect the underlying superalloy from high-temperature corrosion. A feature of importance to the durability of thermal barrier coatings is the early establishment of a continuous, protective oxide layer (preferably {alpha}-alumina) at the bond coating-ceramic interface. Because zirconia is permeable to oxygen, this oxide layer continues to grow during service. Some superalloys are inherently resistant to high-temperature oxidation, so a separate bond coating may not be needed in those cases. Thermal barrier coatings have been in service in aeroengines for a number of years, and the use of this technology for increasing the durability and/or efficiency of industrial gas turbines is currently of significant interest. The data presented were taken from an investigation of routes to optimize bond coating performance, and the focus of the paper is on the influences of reactive elements and Pt on the oxidation behaviour of NiAl-based alloys determined in studies using cast versions of bond coating compositions.

  3. A complete qualification methodology for coatings of precision glass molding tools

    NASA Astrophysics Data System (ADS)

    Klocke, F.; Georgiadis, K.; Dambon, O.; Bouzakis, K.-D.; Gerardis, S.; Skordaris, G.

    2011-09-01

    Precision glass molding is the technology of choice for the production of complex-shaped optical components. Protective coatings can significantly extend the lifetime of the molding tools, but the coating properties have to be exactly customized for the individual application conditions, or else an improvement in the tool performance cannot be guaranteed. The currently biggest challenge is to ensure the reliability of newly developed coatings without resorting to extensive and expensive practical testing. However, the usual coating qualification methods either cannot be used or don't provide meaningful results. In this work a new three-tier, application-specific methodology for the qualification such coatings is presented.

  4. Plasma-Sprayed Ceramic Coatings for Barrier Applications Against Molten Uranium Corrosion

    NASA Astrophysics Data System (ADS)

    Ananthapadmanabhan, P. V.; Chakravarthy, Y.; Chaturvedi, Vandana; Thiyagarajan, T. K.; Pragatheeswaran, A.

    2015-07-01

    Ceramic coatings are applied on engineering components for protecting them from large thermal load and hot corrosion. Choices of coating material for protection against hot corrosion by uranium are few, because of its high reactivity. Yttrium oxide has a high melting temperature and is inert towards uranium. Therefore, yttrium oxide coatings are effective as a barrier against hot corrosion by uranium and its alloys. This paper gives a summary of the developmental work on plasma-sprayed yttria coatings for corrosion barrier applications against molten uranium. Results show that plasma-sprayed yttria coatings offer a long-term solution to hot corrosion problems.

  5. Coated particle waste form development

    SciTech Connect

    Oma, K.H.; Buckwalter, C.Q.; Chick, L.A.

    1981-12-01

    Coated particle waste forms have been developed as part of the multibarrier concept at Pacific Northwest Laboratory under the Alternative Waste Forms Program for the Department of Energy. Primary efforts were to coat simulated nuclear waste glass marbles and ceramic pellets with low-temperature pyrolytic carbon (LT-PyC) coatings via the process of chemical vapor deposition (CVD). Fluidized bed (FB) coaters, screw agitated coaters (SAC), and rotating tube coaters were used. Coating temperatures were reduced by using catalysts and plasma activation. In general, the LT-PyC coatings did not provide the expected high leach resistance as previously measured for carbon alone. The coatings were friable and often spalled off the substrate. A totally different concept, thermal spray coating, was investigated at PNL as an alternative to CVD coating. Flame spray, wire gun, and plasma gun systems were evaluated using glass, ceramic, and metallic coating materials. Metal plasma spray coatings (Al, Sn, Zn, Pb) provided a two to three orders-of-magnitude increase in chemical durability. Because the aluminum coatings were porous, the superior leach resistance must be due to either a chemical interaction or to a pH buffer effect. Because they are complex, coated waste form processes rank low in process feasibility. Of all the possible coated particle processes, plasma sprayed marbles have the best rating. Carbon coating of pellets by CVD ranked ninth when compared with ten other processes. The plasma-spray-coated marble process ranked sixth out of eleven processes.

  6. Inspecting thermal barrier coatings by IR thermography

    NASA Astrophysics Data System (ADS)

    Bison, Paolo G.; Marinetti, Sergio; Grinzato, Ermanno G.; Vavilov, Vladimir P.; Cernuschi, Federico; Robba, Daniele

    2003-04-01

    As far as power generation is concerned, coating technologies find the main and more advanced applications. Nowadays, superalloys available for manufacturing hot path components in gas turbine like combustion liners, blades and vanes can not sustain temperatures up to 1100°C. In order to guarantee a significative temperature drop ceramic thermal barrier coatings are deposited onto the metallic core. The thickness of thermal barrier coatings (TBC) ranges from a few hundreds microns up to 1 millimetre or more, depending on component and deposition technique (mainly Air Plasma Spray or Electron Beam Physical Vapour Deposition). The structural integrity of both the substrate and the coating and their mutual adhesion is a key point because any loss of the protective layer exposes the bulk material to an extremely aggressive environment in terms of oxidation and temperature. Therefore, TBC must be tested for detecting of defects during both quality control and periodic in-service inspections. Because of the key role played by thickness and low thermal diffusivity of TBC in the decreasing of the substrate material temperature, both delaminations and thickness variation must be detected and classified. Pulsed Thermography has been successfully applied to this application field. Nevertheless, the procedure gives ambiguous results when thickness or thermal properties change in a continuous way within the thermal barrier. In this paper, a specific study on the detection performances of NDE techniques is presented, even when a non-uniform TBC thickness is superimposed to the disbonding defect. Tests performed at workshop on real and specifically manufactured components are reported. Dedicated processing algorithms improving the test reliability and effectiveness are presented as well. Tests on real components on the field are also reported.

  7. Thermal barrier coatings application in diesel engines

    NASA Technical Reports Server (NTRS)

    Fairbanks, J. W.

    1995-01-01

    Commercial use of thermal barrier coatings in diesel engines began in the mid 70's by Dr. Ingard Kvernes at the Central Institute for Industrial Research in Oslo, Norway. Dr. Kvernes attributed attack on diesel engine valves and piston crowns encountered in marine diesel engines in Norwegian ships as hot-corrosion attributed to a reduced quality of residual fuel. His solution was to coat these components to reduce metal temperature below the threshold of aggressive hot-corrosion and also provide protection. Roy Kamo introduced thermal barrier coatings in his 'Adiabatic Diesel Engine' in the late 70's. Kamo's concept was to eliminate the engine block water cooling system and reduce heat losses. Roy reported significant performance improvements in his thermally insulated engine at the SAE Congress in 1982. Kamo's work stimulates major programs with insulated engines, particularly in Europe. Most of the major diesel engine manufacturers conducted some level of test with insulated combustion chamber components. They initially ran into increased fuel consumption. The German engine consortium had Prof. Woschni of the Technical Institute in Munich. Woschni conducted testing with pistons with air gaps to provide the insulation effects. Woschni indicated the hot walls of the insulated engine created a major increase in heat transfer he refers to as 'convection vive.' Woschni's work was a major factor in the abrupt curtailment of insulated diesel engine work in continental Europe. Ricardo in the UK suggested that combustion should be reoptimized for the hot-wall effects of the insulated combustion chamber and showed under a narrow range of conditions fuel economy could be improved. The Department of Energy has supported thermal barrier coating development for diesel engine applications. In the Clean Diesel - 50 Percent Efficient (CD-50) engine for the year 2000, thermal barrier coatings will be used on piston crowns and possibly other components. The primary purpose of the

  8. Thermal barrier coatings application in diesel engines

    NASA Technical Reports Server (NTRS)

    Fairbanks, J. W.

    1995-01-01

    Commercial use of thermal barrier coatings in diesel engines began in the mid 70's by Dr. Ingard Kvernes at the Central Institute for Industrial Research in Oslo, Norway. Dr. Kvernes attributed attack on diesel engine valves and piston crowns encountered in marine diesel engines in Norwegian ships as hot-corrosion attributed to a reduced quality of residual fuel. His solution was to coat these components to reduce metal temperature below the threshold of aggressive hot-corrosion and also provide protection. Roy Kamo introduced thermal barrier coatings in his 'Adiabatic Diesel Engine' in the late 70's. Kamo's concept was to eliminate the engine block water cooling system and reduce heat losses. Roy reported significant performance improvements in his thermally insulated engine at the SAE Congress in 1982. Kamo's work stimulates major programs with insulated engines, particularly in Europe. Most of the major diesel engine manufacturers conducted some level of test with insulated combustion chamber components. They initially ran into increased fuel consumption. The German engine consortium had Prof. Woschni of the Technical Institute in Munich. Woschni conducted testing with pistons with air gaps to provide the insulation effects. Woschni indicated the hot walls of the insulated engine created a major increase in heat transfer he refers to as 'convection vive.' Woschni's work was a major factor in the abrupt curtailment of insulated diesel engine work in continental Europe. Ricardo in the UK suggested that combustion should be reoptimized for the hot-wall effects of the insulated combustion chamber and showed under a narrow range of conditions fuel economy could be improved. The Department of Energy has supported thermal barrier coating development for diesel engine applications. In the Clean Diesel - 50 Percent Efficient (CD-50) engine for the year 2000, thermal barrier coatings will be used on piston crowns and possibly other components. The primary purpose of the

  9. Progress in advanced high temperature turbine materials, coatings, and technology

    NASA Technical Reports Server (NTRS)

    Freche, J. C.; Ault, G. M.

    1978-01-01

    Advanced materials, coatings, and cooling technology is assessed in terms of improved aircraft turbine engine performance. High cycle operating temperatures, lighter structural components, and adequate resistance to the various environmental factors associated with aircraft gas turbine engines are among the factors considered. Emphasis is placed on progress in development of high temperature materials for coating protection against oxidation, hot corrosion and erosion, and in turbine cooling technology. Specific topics discussed include metal matrix composites, superalloys, directionally solidified eutectics, and ceramics.

  10. Reducing Corrosion Control Costs with Rapid-Cure Coatings

    DTIC Science & Technology

    2007-01-01

    investigated and employed in the Single Coat Program include a broad spectrum of materials — epoxies, polyurethanes, polyureas, polyesters , and...of the polyol -isocyanate reaction to fulfill the basic properties of forming a solid material from two liquid components. The art is in understand...ing the behavior of the polyol and isocyanate com- ponents. Because of the reactivity of isocyanates with water, polyurethane coatings must be

  11. Proceedings of the 1987 coatings for advanced heat engines workshop

    SciTech Connect

    Not Available

    1987-01-01

    This Workshop was conducted to enhance communication among those involved in coating development for improved heat engine performance and durability. We were fortunate to have Bill Goward review the steady progress and problems encountered along the way in the use of thermal barrier coatings (TBC) in aircraft gas turbine engines. Navy contractors discussed their work toward the elusive goal of qualifying TBC for turbine airfoil applications. In the diesel community, Caterpillar and Cummins are developing TBC for combustion chamber components as part of the low heat rejection diesel engine concept. The diesel engine TBC work is based on gas turbine technology with a goal of more than twice the thickness used on gas turbine engine components. Adoption of TBC in production for diesel engines could justify a new generation of plasma spray coating equipment. Increasing interests in tribology were evident in this Workshop. Coatings have a significant role in reducing friction and wear under greater mechanical loadings at higher temperatures. The emergence of a high temperature synthetic lubricant could have an enormous impact on diesel engine design and operating conditions. The proven coating processes such as plasma spray, electron-beam physical vapor deposition, sputtering, and chemical vapor deposition have shown enhanced capabilities, particularly with microprocessor controls. Also, the newer coating schemes such as ion implantation and cathodic arc are demonstrating intriguing potential for engine applications. Coatings will play an expanding role in higher efficiency, more durable heat engines.

  12. Mechanical Property of HVOF Inconel 718 Coating for Aeronautic Repair

    NASA Astrophysics Data System (ADS)

    Lyphout, Christophe; Fasth, Angelica; Nylen, Per

    2014-02-01

    The module of elasticity is one of the most important mechanical properties defining the strength of a material which is a prerequisite to design a component from its early stage of conception to its field of application. When a material is to be thermally sprayed, mechanical properties of the deposited layers differ from the bulk material, mainly due to the anisotropy of the highly textured coating microstructure. The mechanical response of the deposited layers significantly influences the overall performance of the coated component. It is, therefore, of importance to evaluate the effective module of elasticity of the coating. Conventional experimental methods such as microindentation, nanoindentation and four-point bending tests have been investigated and their results vary significantly, mainly due to inhomogeneous characteristics of the coating microstructure. Synchrotron radiation coupled with a tensile test rig has been proposed as an alternative method to determine the coating anisotropic elastic behavior dependence on crystallographic orientations. The investigation was performed on Inconel 718 (IN718) HVOF coatings sprayed on IN718 substrates. Combining these experimental techniques yield a deeper understanding of the nature of the HVOF coating Young's modulus and thus a tool for Design Practice for repair applications.

  13. Oxide Dispersion Strengthened Iron Aluminide by CVD Coated Powders

    SciTech Connect

    Asit Biswas Andrew J. Sherman

    2006-09-25

    This I &I Category2 program developed chemical vapor deposition (CVD) of iron, aluminum and aluminum oxide coated iron powders and the availability of high temperature oxidation, corrosion and erosion resistant coating for future power generation equipment and can be used for retrofitting existing fossil-fired power plant equipment. This coating will provide enhanced life and performance of Coal-Fired Boilers components such as fire side corrosion on the outer diameter (OD) of the water wall and superheater tubing as well as on the inner diameter (ID) and OD of larger diameter headers. The program also developed a manufacturing route for readily available thermal spray powders for iron aluminide coating and fabrication of net shape component by powder metallurgy route using this CVD coated powders. This coating can also be applid on jet engine compressor blade and housing, industrial heat treating furnace fixtures, magnetic electronic parts, heating element, piping and tubing for fossil energy application and automotive application, chemical processing equipment , heat exchanger, and structural member of aircraft. The program also resulted in developing a new fabrication route of thermal spray coating and oxide dispersion strengthened (ODS) iron aluminide composites enabling more precise control over material microstructures.

  14. Controlled Thermal Expansion Coat for Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Brindley, William J. (Inventor); Miller, Robert A. (Inventor); Aikin, Beverly J. M. (Inventor)

    1999-01-01

    A improved thermal barrier coating and method for producing and applying such is disclosed herein. The thermal barrier coating includes a high temperature substrate, a first bond coat layer applied to the substrate of MCrAlX, and a second bond coat layer of MCrAlX with particles of a particulate dispersed throughout the MCrAlX and the preferred particulate is Al2O3. The particles of the particulate dispersed throughout the second bond coat layer preferably have a diameter of less then the height of the peaks of the second bond coat layer, or a diameter of less than 5 microns. The method of producing the second bond coat layer may either include the steps of mechanical alloying of particles throughout the second bond coat layer, attrition milling the particles of the particulate throughout the second bond coat layer, or using electrophoresis to disperse the particles throughout the second bond coat layer. In the preferred embodiment of the invention, the first bond coat layer is applied to the substrate, and then the second bond coat layer is thermally sprayed onto the first bond coat layer. Further, in a preferred embodiment of die invention, a ceramic insulating layer covers the second bond coat layer.

  15. Protective coatings for metal alloys and methods incorporating the same

    DOEpatents

    Seabaugh, Matthew M.; Ibanez, Sergio; Swartz, Scott L.

    2015-06-09

    An electrochemical device having one or more solid oxide fuel cells (SOFCs), each of the SOFCs including a cathode, an anode, and an electrolyte layer positioned between the cathode and anode; and at least one additional component comprising a metallic substrate having an electronically conductive, chromium-free perovskite coating deposited directly thereon. The perovskite coating has the formula ABO.sub.3, wherein A is a lanthanide element or Y, and B is a mixture of two or more transition elements, with the A site undoped by any alkaline earth element, and the perovskite coating exhibits limited or no ionic transport of oxygen.

  16. Gold coated ZnO nanorod biosensor for glucose detection

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Anuradha; Jain, Chhavi; Rao, V. Padmanapan; Banerjee, S.

    2012-06-01

    Gold coated ZnO nanorod based biosensor has been fabricated for its glucose detecting abilities and compared with that of ZnO nanorod based biosensor. SEM images of electrochemically grown ZnO nanorods show hexagonally grown ZnO nanorods on an ITO substrate. Electrochemical analysis show that gold coated ZnO based biosensors have higher sensitivity, lower limit of detection and a wider linear range for glucose detection. The results demonstrate that gold coated ZnO nanorod based biosensors are a promising material for biosensor applications over single component ZnO nanorod based biosensor.

  17. Hybrid calcium phosphate coatings for implants

    NASA Astrophysics Data System (ADS)

    Malchikhina, Alena I.; Shesterikov, Evgeny V.; Bolbasov, Evgeny N.; Ignatov, Viktor P.; Tverdokhlebov, Sergei I.

    2016-08-01

    Monophasic biomaterials cannot provide all the necessary functions of bones or other calcined tissues. It is necessary to create for cancer patients the multiphase materials with the structure and composition simulating the natural bone. Such materials are classified as hybrid, obtained by a combination of chemically different components. The paper presents the physical, chemical and biological studies of coatings produced by hybrid technologies (HT), which combine primer layer and calcium phosphate (CaP) coating. The first HT type combines the method of vacuum arc titanium primer layer deposition on a stainless steel substrate with the following micro-arc oxidation (MAO) in phosphoric acid solution with addition of calcium compounds to achieve high supersaturated state. MAO CaP coatings feature high porosity (2-8%, pore size 5-7 µm) and surface morphology with the thickness greater than 5 µm. The thickness of Ti primer layer is 5-40 µm. Amorphous MAO CaP coating micro-hardness was measured at maximum normal load Fmax = 300 mN. It was 3.1 ± 0.8 GPa, surface layer elasticity modulus E = 110 ± 20 GPa, roughness Ra = 0.9 ± 0.1 µm, Rz = 7.5 ± 0.2 µm, which is less than the titanium primer layer roughness. Hybrid MAO CaP coating is biocompatible, able to form calcium phosphates from supersaturated body fluid (SBF) solution and also stimulates osteoinduction processes. The second HT type includes the oxide layer formation by thermal oxidation and then CaP target radio frequency magnetron sputtering (RFMS). Oxide-RFMS CaP coating is a thin dense coating with good adhesion to the substrate material, which can be used for metal implants. The RFMS CaP coating has thickness 1.6 ± 0.1 µm and consists of main target elements calcium and phosphorus and Ca/P ratio 2.4. The second HT type can form calcium phosphates from SBF solution. In vivo study shows that hybrid RFMS CaP coating is biocompatible and produces fibrointegration processes.

  18. The Development of Environmental Barrier Coating Systems for SiC-SiC Ceramic Matrix Composites: Environment Effects on the Creep and Fatigue Resistance

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Ghosn, Louis J.

    2014-01-01

    Topics covered include: Environmental barrier coating system development: needs, challenges and limitations; Advanced environmental barrier coating systems (EBCs) for CMC airfoils and combustors; NASA EBC systems and material system evolutions, Current turbine and combustor EBC coating emphases, Advanced development, processing, testing and modeling, EBC and EBC bond coats: recent advances; Design tool and life prediction of coated CMC components; Advanced CMC-EBC rig demonstrations; Summary and future directions.

  19. Pratt & Whitney thermal barrier coatings

    SciTech Connect

    Bornstein, N.; Marcin, J.

    1995-10-01

    The objective of the Advanced Turbine Systems (ATS) Program is to develop ultra-high efficient, environmentally superior, and cost competitive gas turbine systems. The operating profiles of these industrial gas turbines are long, less cyclic with fewer transients-compared with those for aircraft gas turbine engines. Therefore, creep rather than thermal fatigue, becomes primary life-limiting for hot section components. Thermal barrier coatings (TBCs) will be used to achieve the objectives of the program. TBCs allow surface temperatures to increase without compromising the structural properties of the alloy. TBCs typically consist of a ceramic insulating layer, deposited onto the substrate with an intervening metallic layer, which imparts oxidation protection to the substrate and provides a surface to which the ceramic layer can adhere.

  20. Moesin regulates the trafficking of nascent clathrin-coated vesicles.

    PubMed

    Barroso-González, Jonathan; Machado, José-David; García-Expósito, Laura; Valenzuela-Fernández, Agustín

    2009-01-23

    Clathrin-coated vesicles are responsible for the trafficking of several internalized biological cargos. We have observed that the endogenous F-actin-linker moesin co-distributes with constitutive components of clathrin-coated structures. Total internal reflection fluorescence microscopy studies have shown that short interference RNA of moesin enhances the lateral movement of clathrin-coated structures and provokes their abnormal clustering. The aggregation of clathrin-coated structures has also been observed in cells overexpressing N-moesin, a dominant-negative construct unable to bind to F-actin. Only overexpressed moesin constructs with an intact phosphatidylinositol 4,5-bisphosphate-binding domain co-distribute with clathrin-coated structures. Hence, this N-terminal domain is mostly responsible for moesin/clathrin-coated structure association. Biochemical endosome fractioning together with total internal reflection fluorescence microscopy comparative studies, between intact cells and plasma-membrane sheets, indicate that moesin knockdown provokes the accumulation of endocytic rab5-clathrin-coated vesicles carrying the transferrin receptor. The altered trafficking of these endocytic rab5-clathrin-coated vesicles accounts for a transferrin receptor recycling defect that reduces cell-surface expression of the transferrin receptor and increases the amount of sequestered transferrin ligand. Therefore, we propose that moesin is a clathrin-coated vesicle linker that drives cargo trafficking and acts on nascent rab5-clathrin-coated vesicles by simultaneously binding to clathrin-coated vesicle-associated phosphatidylinositol 4,5-bisphosphate and actin cytoskeleton. Hence, functional alterations of moesin may be involved in pathological disorders associated with clathrin-mediated internalization or receptor recycling.