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Sample records for cold coated materials

  1. Titanium Cold Spray Coatings

    NASA Astrophysics Data System (ADS)

    Ajaja, Jihane; Goldbaum, Dina; Chromik, Richard; Yue, Stephen; Rezaeian, Ahmad; Wong, Wilson; Irissou, Eric; Legoux, Jean-Gabriel

    Titanium Cold Spray Coatings Cold Spray is an emerging technology used for the deposition of coatings for many industries including aerospace. This technique allows the deposition of metallic materials at low temper-atures below their melting point. The aim of this research was to develop a test technique that can measure the degree to which a cold spray coating achieves mechanical properties similar to a traditional bulk material. Vickers hardness testing and nanoindentation were used as micro-and nano-scale measurement techniques to characterize the mechanical properties of titanium coatings, deposited at different deposition conditions, and bulk Ti. The mechanical properties of bulk titanium and titanium coatings were measured over a range of length scales, with the indentation size effect examined with Meyer's law. Hardness measurements are shown to be affected by material porosity, microstructure and coating particle bonding mechanism. Hard-ness measurements showed that Ti coatings deposited at higher gas pressures and temperatures demonstrate an indentation load response similar to bulk Ti. Key words: titanium, cold spray, Vickers hardness, nanoindentation, indentation size effect, microstructure, mechanical properties

  2. Development of barrier coatings for cellulosic-based materials by cold plasma methods

    NASA Astrophysics Data System (ADS)

    Denes, Agnes Reka

    Cellulose-based materials are ideal candidates for future industries that need to be based on environmentally safe technologies and renewable resources. Wood represents an important raw material and its application as construction material is well established. Cellophane is one of the most important cellulosic material and it is widely used as packaging material in the food industry. Outdoor exposure of wood causes a combination of physical and chemical degradation processes due to the combined effects of sunlight, moisture, fungi, and bacteria. Cold-plasma-induced surface modifications are an attractive way for tailoring the characteristics of lignocellulosic substrates to prevent weathering degradation. Plasma-polymerized hexamethyldisiloxane (PPHMDSO) was deposited onto wood surfaces to create water repellent characteristics. The presence of a crosslinked macromolecular structure was detected. The plasma coated samples exhibited very high water contact angle values indicating the existence of hydrophobic surfaces. Reflective and electromagnetic radiation-absorbent substances were incorporated with a high-molecular-weight polydimethylsiloxane polymer in liquid phase and deposited as thin layers on wood surfaces. The macromolecular films, containing the dispersed materials, were then converted into a three dimensional solid state network by exposure to a oxygen-plasma. It was demonstrated that both UV-absorbent and reflectant components incorporated into the plasma-generated PDMSO matrix protected the wood from weathering degradation. Reduced oxidation and less degradation was observed after simulated weathering. High water contact angle values indicated a strong hydrophobic character of the oxygen plasma-treated PDMSO-coated samples. Plasma-enhanced surface modifications and coatings were employed to create water-vapor barrier layers on cellophane substrate surfaces. HMDSO was selected as a plasma gas and oxygen was used to ablate amorphous regions. Oxygen plasma

  3. Cold Sprayed Intermetallic Thermal Barrier Coatings

    NASA Astrophysics Data System (ADS)

    Leshchinsky, Evgeny

    Conventional thermal barrier coating (TBC) systems consist of a duplex structure with a metallic bond coat and a ceramic heat-isolative topcoat. Several recent research activities are concentrated on the development of improved multilayer bond coat and TBC materials. This study represents an investigation performed for the aluminum based bond coats, especially those with reduced thermal conductivities. Using alternative TBC materials, such as metal alloys and intermetallics, their processing methods can be further optimized to achieve the best thermal physical parameters. One example is the ten-layer system in which cold sprayed aluminum based intermetallics are synthesized. These systems demonstrated improved heat insulation and thermal fatigue capabilities compared to conventional TBC. The microstructures and properties of the laminar coatings were characterized by SEM, EDS, XRD; micromechanical and durability tests were performed to define the structure and coating formation mechanisms. Application prospects for HCCI engines are discussed. Fuel energy can be utilized more efficiently with the concept of low heat rejection engines with applied TBC.

  4. The temperature dependence of ultra-cold neutron wall losses in material bottles coated with deuterated polystryene

    SciTech Connect

    Cooper, Martiin D; Bagdasarova, Yelena; Clayton, Steven M; Currie, Scott A; Griffith, William C; Ito, Takeyasu; Makela, Mark F; Morris, Cheistopher; Rahaman, Mohamad S; Ramsey, John C; Saunders, Alexander; Rios, Raymond

    2011-01-18

    Ultra-cold neutrons (UCN) from the LANSCE super-thermal deuterium source were used to fill an acrylic bottle coated with deuterated polystyrene. The bottle was constructed to minimize losses through the filling valve. The storage time was extracted from a series of measurements where the number of neutrons was counted after they were held in the bottle for durations varying from 60-1200 s. The data were collected at temperatures of 18, 40, 65, 105, and 295 K. The data has been analyzed in terms of the ratio of the imaginary to real part of the wall potential. The analysis considers the velocity dependence of the probability per bounce of wall loss. The implication of these measurements for the SNS electric dipole moment search will be presented.

  5. 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.

  6. Cold-Sprayed Nanostructured Pure Cobalt Coatings

    NASA Astrophysics Data System (ADS)

    Cavaliere, P.; Perrone, A.; Silvello, A.

    2016-08-01

    Cold-sprayed pure cobalt coatings were deposited on carbon-steel substrate. Submicrometer particles for spraying were produced via cryomilling. Deposits were produced using different processing conditions (gas temperature and pressure, nozzle-to-substrate distance) to evaluate the resulting variations in grain size dimension, microhardness, adhesion strength, and porosity. The coating mechanical properties improved greatly with higher temperature and carrying-gas pressure. The coating microstructure was analyzed as a function of spraying condition by transmission electron microscopy (TEM) observations, revealing many different microstructural features for coatings experiencing low or high strain rates during deposition.

  7. Deuterated polyethylene coatings for ultra-cold neutron applications

    SciTech Connect

    Brenner, Th.; Geltenbort, P.; Fierlinger, P.; Gutsmiedl, E.; Hollering, A.; Petzoldt, G.; Ruhstorfer, D.; Stuiber, St.; Taubenheim, B.; Windmayer, D.; Lauer, T.; Schroffenegger, J.; Zechlau, T.; Seemann, K. M.; Soltwedel, O.

    2015-09-21

    We report on the fabrication and use of deuterated polyethylene as a coating material for ultra-cold neutron (UCN) storage and transport. The Fermi potential has been determined to be 214 neV, and the wall loss coefficient η is 1.3 × 10{sup 4} per wall collision. The coating technique allows for a wide range of applications in this field of physics. In particular, flexible and quasi-massless UCN guides with slit-less shutters and seamless UCN storage volumes become possible. These properties enable the use in next-generation measurements of the electric dipole moment of the neutron.

  8. Deuterated polyethylene coatings for ultra-cold neutron applications

    NASA Astrophysics Data System (ADS)

    Brenner, Th.; Fierlinger, P.; Geltenbort, P.; Gutsmiedl, E.; Hollering, A.; Lauer, T.; Petzoldt, G.; Ruhstorfer, D.; Schroffenegger, J.; Seemann, K. M.; Soltwedel, O.; Stuiber, St.; Taubenheim, B.; Windmayer, D.; Zechlau, T.

    2015-09-01

    We report on the fabrication and use of deuterated polyethylene as a coating material for ultra-cold neutron (UCN) storage and transport. The Fermi potential has been determined to be 214 neV, and the wall loss coefficient η is 1.3 × 104 per wall collision. The coating technique allows for a wide range of applications in this field of physics. In particular, flexible and quasi-massless UCN guides with slit-less shutters and seamless UCN storage volumes become possible. These properties enable the use in next-generation measurements of the electric dipole moment of the neutron.

  9. Improved bonding strength of bioactive cermet Cold Gas Spray coatings.

    PubMed

    Gardon, M; Concustell, A; Dosta, S; Cinca, N; Cano, I G; Guilemany, J M

    2014-12-01

    The fabrication of cermet biocompatible coatings by means Cold Gas Spray (CGS) provides prosthesis with outstanding mechanical properties and the required composition for enhancing the bioactivity of prosthetic materials. In this study, hydroxyapatite/Titanium coatings were deposited by means of CGS technology onto titanium alloy substrates with the aim of building-up well-bonded homogeneous coatings. Powders were blended in different percentages and sprayed; as long as the amount of hydroxyapatite in the feedstock increased, the quality of the coating was reduced. Besides, the relation between the particle size distribution of ceramic and metallic particles is of significant consideration. Plastic deformation of titanium particles at the impact eased the anchoring of hard hydroxyapatite particles present at the top surface of the coating, which assures the looked-for interaction with the cells. Coatings were immersed in Hank's solution for 1, 4 and 7 days; bonding strength value was above 60 MPa even after 7 days, which enhances common results of HAp coatings obtained by conventional thermal spray technologies. PMID:25491809

  10. The Elastic Modulus of Cold Spray Coatings: Influence of Inter-splat Boundary Cracking

    NASA Astrophysics Data System (ADS)

    Sundararajan, G.; Chavan, Naveen M.; Kumar, S.

    2013-12-01

    It is well established that cold spray coatings exhibit substantially lower elastic modulus as compared to bulk material of the same composition. It has also been observed that the heat treatment of the cold spray coatings results in a significant increase in the elastic modulus of the coating. To check whether the presence of inter-splat cracks is responsible for the above behavior, a wide variety of metallic materials (Cu, Ag, Zn, Nb, Ta, Ti, and 316L stainless steels) in the powder form have been deposited on a mild steel substrate using the cold spray technique. These coatings in both as-coated and heat-treated conditions have been characterized for their porosity, extent of inter-splat boundary cracking, hardness, and elastic modulus. Results indicate that the elastic modulus of the coatings are substantially lower than the bulk value and also that the heat treatment of the coatings consistently increase their elastic modulus values. It has been shown that the reduction in elastic modulus of cold spray coatings can be related to the extent of inter-splat boundary cracking. Further, it has been shown that the standard models relating elastic modulus to the crack density are capable of explaining the observed modulus in the case of cold spray coatings in the as-coated and heat-treated conditions.

  11. Phase Stability of Al-5Fe-V-Si Coatings Produced by Cold Gas Dynamic Spray Process Using Rapidly Solidified Feedstock Materials

    NASA Astrophysics Data System (ADS)

    Bérubé, G.; Yandouzi, M.; Zúñiga, A.; Ajdelsztajn, L.; Villafuerte, J.; Jodoin, B.

    2012-03-01

    In this study, aluminum alloy Al-5Fe-V-Si (in wt.%) feedstock powder, produced by rapid solidification (RS) using the gas atomization process, was selected to produce high-temperature resistant Al-alloy coatings using the cold gas dynamic spraying process (CGDS). The alloy composition was chosen for its mechanical properties at elevated temperature for potential applications in internal-combustion (IC) engines. The CGDS spray process was selected due to its relatively low operating temperature, thus preventing significant heating of the particles during spraying and as such allowing the original phases of the feedstock powder to be preserved within the coatings. The microstructure and phases stability was investigated by means of Scanning Electron Microscopy, transmission electron microscopy, X-ray diffraction and differential scanning calorimetery techniques. The coatings mechanical properties were evaluated through bond strength and microhardness testing. The study revealed the conservation of the complex microstructure of the rapid solidified powder during the spray process. Four distinct microstructures were observed as well as two different phases, namely a Al13(Fe,V)3Si silicide phase and a metastable (Al,Si) x (Fe,V) Micro-quasicrystalline Icosahedral (MI) phase. Aging of the coating samples was performed and confirmed that the phase transformation of the metastable phases and coarsening of the nanosized precipitates will occurs at around 400 °C. The metastable MI phase was determined to be thermally stable up to 390 °C, after which a phase transformation to silicide starts to occur.

  12. Methods for Coating Particulate Material

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    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.

  13. Protective coating for ceramic materials

    NASA Technical Reports Server (NTRS)

    Kourtides, Demetrius A. (Inventor); Churchward, Rex A. (Inventor); Lowe, David M. (Inventor)

    1994-01-01

    A protective coating for ceramic materials such as those made of silicon carbide, aluminum oxide, zirconium oxide, aluminoborosilicate and silicon dioxide, and a thermal control structure comprising a ceramic material having coated thereon the protective coating. The protective coating contains, in admixture, silicon dioxide powder, colloidal silicon dioxide, water, and one or more emittance agents selected from silicon tetraboride, silicon hexaboride, silicon carbide, molybdenum disilicide, tungsten disilicide and zirconium diboride. In another aspect, the protective coating is coated on a flexible ceramic fabric which is the outer cover of a composite insulation. In yet another aspect, a metallic foil is bonded to the outer surface of a ceramic fabric outer cover of a composite insulation via the protective coating. A primary application of this invention is as a protective coating for ceramic materials used in a heat shield for space vehicles subjected to very high aero-convective heating environments.

  14. Crystallization Evolution of Cold-Sprayed Pure Ni Coatings

    NASA Astrophysics Data System (ADS)

    Cavaliere, P.; Perrone, A.; Silvello, A.

    2016-07-01

    Cold spraying is a coating technology on the basis of aerodynamics and high-speed impact dynamics. Spray particles (usually 1-50 μm in diameter) are accelerated to high velocity (typically 300-1200 m/s) by a high-speed gas (preheated air, nitrogen, or helium) flow that is generated through a convergent-divergent de Laval type nozzle. The coating forms through the intensive plastic deformation of particles impacting on the substrate at temperatures well below the melting point of the spray material. In the present paper, the main processing parameters affecting the crystallization behavior of pure Ni cold spray deposits on IN718 alloy are described. Various experimental conditions have been analyzed: gas temperature and pressure, nozzle to substrate distance. In particular, the study deals with those conditions leading to a strong grain refinement, with an acceptable level of the deposits mechanical properties. In precise spray conditions, a shift toward amorphous phases has been observed and studied. A systematic analysis of microstructural evolution, performed through TEM observations, as a function of processing parameters is presented.

  15. Crystallization Evolution of Cold-Sprayed Pure Ni Coatings

    NASA Astrophysics Data System (ADS)

    Cavaliere, P.; Perrone, A.; Silvello, A.

    2016-08-01

    Cold spraying is a coating technology on the basis of aerodynamics and high-speed impact dynamics. Spray particles (usually 1-50 μm in diameter) are accelerated to high velocity (typically 300-1200 m/s) by a high-speed gas (preheated air, nitrogen, or helium) flow that is generated through a convergent-divergent de Laval type nozzle. The coating forms through the intensive plastic deformation of particles impacting on the substrate at temperatures well below the melting point of the spray material. In the present paper, the main processing parameters affecting the crystallization behavior of pure Ni cold spray deposits on IN718 alloy are described. Various experimental conditions have been analyzed: gas temperature and pressure, nozzle to substrate distance. In particular, the study deals with those conditions leading to a strong grain refinement, with an acceptable level of the deposits mechanical properties. In precise spray conditions, a shift toward amorphous phases has been observed and studied. A systematic analysis of microstructural evolution, performed through TEM observations, as a function of processing parameters is presented.

  16. Mechanical and Microstructural Behavior of Cold-Sprayed Titanium- and Nickel-Based Coatings

    NASA Astrophysics Data System (ADS)

    Cavaliere, P.; Silvello, A.

    2015-12-01

    Cold spraying is a coating technology that can deposit materials with unique properties. The coating forms through intensive plastic deformation of particles impacting on a substrate at temperature well below the melting point of the sprayed material. Recently, various studies have been published regarding the microstructural and mechanical evolution of metal-matrix composite coatings produced by cold spraying. Herein, we describe the principal results of the available literature in the field of cold-sprayed composites. It is shown that more research is required to solve various questions in this field, for example, the different deformation modes of the material exhibited for various processing conditions, the reinforcing percentage of different material combinations, and the mechanical properties resulting from these complex systems. In the present study, this issue is approached and described for cold-sprayed Ni- and Ti-based composites. Materials were produced with varying ceramic phase (BN and TiAl3) fraction. The variation of the grain size, adhesion strength, porosity, and hardness of the deposits as a function of the ceramic phase fraction and processing parameters (impacting particle speed) is described. The interaction mechanisms between the cold-sprayed particles and the metal matrix during the coating process are presented and described. The results demonstrate a beneficial effect on grain size and porosity with increasing reinforcing phase percentage, as well as narrow processing parameter ranges to achieve the optimal properties with respect to the pure parent materials.

  17. Cold sprayed copper coating: numerical study of particle impact and coating characterization

    NASA Astrophysics Data System (ADS)

    Mebdoua, Yamina; Fizi, Yazid; Bouhelal, Nadjet

    2016-05-01

    Cold spraying technique is a promising process fabricating high quality metallic coatings. This work concerns both numerical and experimental investigations of cold sprayed copper coating taking into account impact conditions including, particle velocities and temperature, gas pressure and material nature. The conducted numerical study is an examination of the deformation behavior of Cu particles sprayed onto steel substrate using Abaqus/explicit software, allowing a good understanding of the deposition characteristics of copper particles and the effect of particle velocity on the coating microstructure. The numerical results show that particle impact velocity has a significant effect on its morphology; Lagrangian method exhibits an excessive distortion of the elements in the case of high impact velocity and fine meshing size, whereas simulation of particle impact using arbitrary Lagrangian-Eulerian (ALE) method is close to the experimental observations. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  18. Superhydrophobic Coatings with Edible Materials.

    PubMed

    Wang, Wei; Lockwood, Karsten; Boyd, Lewis M; Davidson, Matthew D; Movafaghi, Sanli; Vahabi, Hamed; Khetani, Salman R; Kota, Arun K

    2016-07-27

    We used FDA-approved, edible materials to fabricate superhydrophobic coatings in a simple, low cost, scalable, single step process. Our coatings display high contact angles and low roll off angles for a variety of liquid products consumed daily and facilitate easy removal of liquids from food containers with virtually no residue. Even at high concentrations, our coatings are nontoxic, as shown using toxicity tests. PMID:27403590

  19. Protective coatings for sensitive materials

    DOEpatents

    Egert, Charles M.

    1997-01-01

    An enhanced protective coating to prevent interaction between constituents of the environment and devices that can be damaged by those constituents. This coating is provided by applying a synergistic combination of diffusion barrier and physical barrier materials. These materials can be, for example, in the form of a plurality of layers of a diffusion barrier and a physical barrier, with these barrier layers being alternated. Further protection in certain instances is provided by including at least one layer of a getter material to actually react with one or more of the deleterious constituents. The coating is illustrated by using alternating layers of an organic coating (such as Parylene-C.TM.) as the diffusion barrier, and a metal coating (such as aluminum) as the physical barrier. For best results there needs to be more than one of at least one of the constituent layers.

  20. Protective coatings for sensitive materials

    DOEpatents

    Egert, C.M.

    1997-08-05

    An enhanced protective coating is disclosed to prevent interaction between constituents of the environment and devices that can be damaged by those constituents. This coating is provided by applying a synergistic combination of diffusion barrier and physical barrier materials. These materials can be, for example, in the form of a plurality of layers of a diffusion barrier and a physical barrier, with these barrier layers being alternated. Further protection in certain instances is provided by including at least one layer of a getter material to actually react with one or more of the deleterious constituents. The coating is illustrated by using alternating layers of an organic coating (such as Parylene-C{trademark}) as the diffusion barrier, and a metal coating (such as aluminum) as the physical barrier. For best results there needs to be more than one of at least one of the constituent layers. 4 figs.

  1. Rheology of Coating Materials and Their Coating Characteristics

    NASA Astrophysics Data System (ADS)

    Grabsch, C.; Grüner, S.; Otto, F.; Sommer, K.

    2008-07-01

    Lots of particles used in the pharmaceutical and the food industry are coated to protect the core material. But almost no investigations about the coating material behavior do exist. In this study the focus was on the rheological material properties of fat based coating materials. Rotational shear experiments to determine the viscosity of a material were compared to oscillatory shear tests to get information about the vicoelastic behavior of the coating materials. At the liquid state the viscosity and the viscoelastic properties showed a good analogy. The viscoelastic properties of the solid coating materials yielded differences between materials that have the same properties at the liquid state.

  2. Protective coatings of metal surfaces by cold plasma treatment

    NASA Technical Reports Server (NTRS)

    Manory, R.; Grill, A.

    1985-01-01

    The cold plasma techniques for deposition of various types of protective coatings are reviewed. The main advantage of these techniques for deposition of ceramic films is the lower process temperature, which enables heat treating of the metal prior to deposition. In the field of surface hardening of steel, significant reduction of treatment time and energy consumption were obtained. A simple model for the plasma - surface reactions in a cold plasma system is presented, and the plasma deposition techniques are discussed in view of this model.

  3. Development of self-lubricating coatings via cold spray process: Feedstock formulation and deformation modeling

    NASA Astrophysics Data System (ADS)

    Aggarwal, Gaurav

    Because of their low density, high specific strength and high stiffness, titanium alloys are one of the prime candidates for structural application often requiring specific tribological properties. However, their relatively high friction coefficients and low wear resistance are limiting their application over a wider temperature range. Various coatings deposited with technologies like high velocity oxy flame (HVOF), detonation gun (DGun), electron beam physical vapor deposition (EB-PVD), etc., can improve wear performance and decrease corrosion damage. These technologies require high processing temperatures precluding the integration of thermally vulnerable lubricants. This research looks at a relatively new coating process called Cold Spray for self-lubricating coatings on Ti-6Al-4V alloys. Cold Spray can produce coatings without significant heating of the sprayed powder or substrate. The particles are in solid state as they hit the substrate, and the formation of coatings occurs mainly due to the kinetic energy of the particles. Therefore, the impact velocity plays an important role. Below a critical value, the particles can cause densification and abrasion of the substrate. The focus of this study is to design composite coatings for the cold spray process and determination of the critical velocity through finite element modeling. Different powders and feedstock formulation techniques are discussed in order to find an optimum formulation for self-lubricating coatings. A composite powder (Ni coated hBN) was found to be the best candidate for the feedstock. The deformation of composite particles upon impact on the substrate was modeled and compared to the experiments. A number of approaches involving different modeling platforms, particle-substrate geometries, and material models have been tried. This work presents the results of ANSYS (version 10.0) analysis using an axisymmetric model of the particle impact. Stress and strain distributions in the particle

  4. Beneficial effects of laser irradiation on the deposition process of diamond/Ni60 composite coating with cold spray

    NASA Astrophysics Data System (ADS)

    Yao, Jianhua; Yang, Lijing; Li, Bo; Li, Zhihong

    2015-03-01

    Although cold spray process has many unique advantages over other coating techniques, it has difficulties in depositing hard materials. This article presents a study in the beneficial effects of laser irradiation on the fabrication process of diamond/Ni60 composite coating using cold spray. The focus of this research is on the comparison between the composite coatings produced with laser cladding (LC) and with supersonic laser deposition (SLD), with respect to diamond graphitization and tribological properties, thus to demonstrate the beneficial effects of laser irradiation on the cold spray process. The influence of deposition temperature on the coating characteristics, such as deposition efficiency, diamond volume fraction, microstructure and phase is also investigated. The tribological properties of the diamond/Ni60 composite coating produced with SLD are determined using a pin-on-disc tribometer, along with the diamond/Ni60 coating produced using LC with the optimal process parameters for comparison. The experimental results show that with the assistance of laser irradiation, diamond/Ni60 composite coating can be successfully deposited using cold spray; the obtained coating is superior to that processed with LC, because SLD can suppress the graphitization of the diamond particles. The diamond/Ni60 composite coating fabricated with SLD has much better tribological properties than the LC coating.

  5. Cold Spraying of Ti2AlC MAX-Phase Coatings

    NASA Astrophysics Data System (ADS)

    Gutzmann, H.; Gärtner, F.; Höche, D.; Blawert, C.; Klassen, T.

    2013-03-01

    Cold spraying was applied to deposit Ti2AlC on different substrate materials. The study of single impacts by scanning electron microscopy indicates that bonding of the first layer is mainly attributed to the deformation and shear instabilities occurring at substrate sites. Nevertheless, as compared to the feedstock particles, the splats appear flattened by the impact. This deformation seems to be attributed not only to local, internal shear but also to internal fracture. By applying up to five passes under optimized spray parameters, Ti2AlC-coatings with thicknesses of about 110-155 μm were achieved. XRD analysis of the coating proved that the crystallographic structure of the feedstock was retained during cold spraying. The coating microstructures show rather low porosity of about <2%, but several cracks between spray layers. Successful build-up of more than one layer can probably be attributed to local deformation of the highly anisotropic Ti2AlC-phase.

  6. Interface Characterization and Bonding Mechanisms of Cold Gas-Sprayed Al Coatings on Ceramic Substrates

    NASA Astrophysics Data System (ADS)

    Drehmann, R.; Grund, T.; Lampke, T.; Wielage, B.; Manygoats, K.; Schucknecht, T.; Rafaja, D.

    2015-01-01

    The aim of the present work is to contribute to the understanding of the adhesion mechanisms, which take effect at the interface of cold gas-sprayed metallic coatings on ceramic substrates. Former investigations revealed that it is possible to deposit well-adhering metallic coatings on atomically smooth ceramics. This led to the conclusion that mechanical interlocking is not always a necessary precondition for bonding. A combination of recrystallization processes induced by adiabatic shear processes and heteroepitaxial growth might be an explanation for the high observed adhesion strengths. The present work focuses on the examination of the interface area of cold gas-sprayed aluminum on various ceramic substrates by means of SEM and HRTEM. Beside sintered corundum plates, single-crystalline sapphire substrates with defined lattice orientations were used as substrates for the deposition of the coatings. In addition to Al2O3 substrates, aluminum coatings were also deposited on AlN, Si3N4, and SiC in order to investigate, whether the different amounts of ionic bonds in these substrate materials have an influence on the substrate/coating interface formation. Additional information about the local heteroepitaxy and its effect on the adhesion of Al coatings was obtained from experiments performed on coatings produced by means of physical vapor deposition.

  7. Cold gas spraying of semiconductor coatings for the photooxidation of water

    NASA Astrophysics Data System (ADS)

    Emmler, T.; Gutzmann, H.; Hillebrand, P.; Schieda, M.; Just, R.; Gärtner, F.; Bogdanoff, P.; Herrmann-Geppert, I.; Klassen, T.

    2013-09-01

    This contribution shows the potential of cold gas spraying for the production of photoelectrodes employing photoelectrocatalysts for the water oxidation reaction. Conventional methods of coating usually employ sol-gel methods and calcination to obtain a good binding of the coating to the substrate. In cold gas spraying, particles are accelerated to high velocities by a pressurized gas. Nitrogen is used as process gas, preheated and then expanded in a De Laval type nozzle. On impact with the substrate the particles deform, break up and build an efficient interface to the back contact (as revealed, for example, by scanning electron microscopy). Cold gas spraying is a method for the direct bonding of particles to a substrate and does not require additives that have to be removed e.g. by a calcination step. Thereby it allows the direct fabrication of a working electrode ensemble. In our initial experiments, the state-of-the-art photocatalyst titanium dioxide (TiO2) was explored. The cold-gas-sprayed coatings revealed significantly higher activities for the oxygen evolution reaction (OER), as compared to films derived from wet-chemical processes. Due to the demand for photocatalysts with band gap suitable for visible light absorption, this approach was extended to the promising catalyst material hematite. In correlation with photoelectrochemical measurements, the operating parameters of the cold gas spray process are discussed in terms of their influence on the photocatalytic properties of the semiconductor.

  8. Armor systems including coated core materials

    SciTech Connect

    Chu, Henry S.; Lillo, Thomas M.; McHugh, Kevin M.

    2012-07-31

    An armor system and method involves providing a core material and a stream of atomized coating material that comprises a liquid fraction and a solid fraction. An initial layer is deposited on the core material by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is less than the liquid fraction of the stream of atomized coating material on a weight basis. An outer layer is then deposited on the initial layer by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is greater than the liquid fraction of the stream of atomized coating material on a weight basis.

  9. Armor systems including coated core materials

    SciTech Connect

    Chu, Henry S; Lillo, Thomas M; McHugh, Kevin M

    2013-10-08

    An armor system and method involves providing a core material and a stream of atomized coating material that comprises a liquid fraction and a solid fraction. An initial layer is deposited on the core material by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is less than the liquid fraction of the stream of atomized coating material on a weight basis. An outer layer is then deposited on the initial layer by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is greater than the liquid fraction of the stream of atomized coating material on a weight basis.

  10. Development of Ultra-High Molecular Weight Polyethylene (UHMWPE) Coating by Cold Spray Technique

    NASA Astrophysics Data System (ADS)

    Ravi, Kesavan; Ichikawa, Yuji; Deplancke, Tiana; Ogawa, Kazuhiro; Lame, Olivier; Cavaille, Jean-Yves

    2015-08-01

    Ultra-high molecular weight polyethylene or UHMWPE is an extremely difficult material to coat with, as it is rubbery and chemically very inert. The Cold Spray process appears to be a promising alternative processing technique but polymers are in general difficult to deposit using this method. So, attempts to develop UHMWPE coatings were made using a downstream injection cold spray technique incorporating a few modifications. A conventional cold spray machine yielded only a few deposited particles of UHMWPE on the substrate surface, but with some modifications in the nozzle geometry (especially the length and inner geometry) a thin coating of 45 μm on Al substrate was obtained. Moreover, experiments with the addition of fumed nano-alumina to the feedstock yielded a coating of 1-4 mm thickness on Al and polypropylene substrates. UHMWPE was seen to be melt crystallized during the coating formation, as can be seen from the differential calorimetry curves. Influence of nano-ceramic particles was explained by observing the creation of a bridge bond between UHMWPE particles.

  11. Photocatalytic Activity of Nanostructured Anatase Coatings Obtained by Cold Gas Spray

    NASA Astrophysics Data System (ADS)

    Gardon, M.; Fernández-Rodríguez, C.; Garzón Sousa, D.; Doña-Rodríguez, J. M.; Dosta, S.; Cano, I. G.; Guilemany, J. M.

    2014-10-01

    This article describes a photocatalytic nanostructured anatase coating deposited by cold gas spray (CGS) supported on titanium sub-oxide (TiO2- x ) coatings obtained by atmospheric plasma spray (APS) onto stainless steel cylinders. The photocatalytic coating was homogeneous and preserved the composition and nanostructure of the starting powder. The inner titanium sub-oxide coating favored the deposition of anatase particles in the solid state. Agglomerated nano-TiO2 particles fragmented when impacting onto the hard surface of the APS TiO2- x bond coat. The rough surface provided by APS provided an ideal scenario for entrapping the nanostructured particles, which may be adhered onto the bond coat due to chemical bonding; a possible bonding mechanism is described. Photocatalytic experiments showed that CGS nano-TiO2 coating was active for photodegrading phenol and formic acid under aqueous conditions. The results were similar to the performance obtained by competitor technologies and materials such as dip-coating P25® photocatalysts. Disparity in the final performance of the photoactive materials may have been caused by differences in grain size and the crystalline composition of titanium dioxide.

  12. Coated woven materials and method of preparation

    DOEpatents

    McCreary, W.J.; Carroll, D.W.

    Coating of woven materials so that not only the outer surfaces are coated has been a problem. Now, a solution to that problem is by coating with materials, with metals or with pyrolytic carbon. Materials are deposited in Chemical Vapor Deposition (CND) reactions using a fluidized bed so that the porosity of the woven materials is retained and the tiny filaments which make up the strands which are woven (including inner as well as outer filaments) are substantially uniformly coated.

  13. Methods and apparatus for coating particulate material

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    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.

  14. Young's Moduli of Cold and Vacuum Plasma Sprayed Metallic Coatings

    NASA Technical Reports Server (NTRS)

    Raj, S. V.; Pawlik, R.; Loewenthal, W.

    2009-01-01

    Monolithic metallic copper alloy and NiCrAlY coatings were fabricated by either the cold spray (CS) or the vacuum plasma spray (VPS) deposition processes. Dynamic elastic modulus property measurements were conducted on these monolithic coating specimens between 300 K and 1273 K using the impulse excitation technique. The Young's moduli decreased almost linearly with increasing temperature at all temperatures except in the case of the CS Cu-23%Cr-5%Al and VPS NiCrAlY, where deviations from linearity were observed above a critical temperature. It was observed that the Young's moduli for VPS Cu-8%Cr were larger than literature data compiled for Cu. The addition of 1%Al to Cu- 8%Cr significantly increased its Young's modulus by 12 to 17% presumably due to a solid solution effect. Comparisons of the Young s moduli data between two different measurements on the same CS Cu- 23%Cr-5%Al specimen revealed that the values measured in the first run were about 10% higher than those in the second run. It is suggested that this observation is due to annealing of the initial cold work microstructure resulting form the cold spray deposition process.

  15. Tribological Testing of Anti-Adhesive coatings for Cold Rolling Mill Rolls—Application to TiN-Coated Rolls

    NASA Astrophysics Data System (ADS)

    Ould, Choumad; Gachon, Yves; Montmitonnet, Pierre; Badiche, Xavier

    2011-05-01

    Roll life is a major issue in cold strip rolling. Roll wear may result either in too low roll roughness, bringing friction below the minimum requested for strip entrainment; or it may degrade strip surface quality. On the contrary, adhesive wear and transfer ("roll coating", "pick up") may form a thick metallic deposits on the roll which increases friction excessively and degrades strip surface again [1]. The roll surface, with the help of a materials-adapted lubricant, must therefore possess anti-wear and anti-adhesive properties. Thus, High Speed Steeel (HSS) rolls show superior properties compared with standard Cr-steel rolls due to their high carbide surface coverage. Another way to improve wear and adhesion properties of surfaces is to apply hard metallic (hard-Cr) or ceramic coatings. Chromium is renowned for its excellent anti-wear and anti-adhesive properties and may serve as a reference. Here, as a first step towards alternative, optimised coatings, a PVD TiN coating has been deposited on tool steels, as previous attempts have proved TiN to be rather successful in cold rolling experiments [2,3]. Different tribological tests are reported here, giving insight in both anti-adhesive properties and fatigue life improvement.

  16. Tribological Testing of Anti-Adhesive coatings for Cold Rolling Mill Rolls--Application to TiN-Coated Rolls

    SciTech Connect

    Ould, Choumad; Montmitonnet, Pierre; Gachon, Yves; Badiche, Xavier

    2011-05-04

    Roll life is a major issue in cold strip rolling. Roll wear may result either in too low roll roughness, bringing friction below the minimum requested for strip entrainment; or it may degrade strip surface quality. On the contrary, adhesive wear and transfer (''roll coating'', ''pick up'') may form a thick metallic deposits on the roll which increases friction excessively and degrades strip surface again [1]. The roll surface, with the help of a materials-adapted lubricant, must therefore possess anti-wear and anti-adhesive properties. Thus, High Speed Steeel (HSS) rolls show superior properties compared with standard Cr-steel rolls due to their high carbide surface coverage. Another way to improve wear and adhesion properties of surfaces is to apply hard metallic (hard-Cr) or ceramic coatings. Chromium is renowned for its excellent anti-wear and anti-adhesive properties and may serve as a reference. Here, as a first step towards alternative, optimised coatings, a PVD TiN coating has been deposited on tool steels, as previous attempts have proved TiN to be rather successful in cold rolling experiments [2,3]. Different tribological tests are reported here, giving insight in both anti-adhesive properties and fatigue life improvement.

  17. Coated woven materials and method of preparation

    DOEpatents

    McCreary, William J.; Carroll, David W.

    1981-01-01

    Coating of woven materials so that not only the outer surfaces are coated has been a problem. Now, a solution to that problem is the following: Woven materials are coated with materials, for example with metals or with pyrolytic carbon, which materials are deposited in Chemical Vapor Deposition (CVD) reactions using a fluidized bed so that the porosity of the woven material is retained and so that the tiny filaments which make up the strands which are woven (including inner as well as outer filaments) are substantially uniformly coated.

  18. Composite and diamond cold cathode materials

    SciTech Connect

    Worthington, M.S.; Wheeland, C.L.; Ramacher, K.; Doyle, E.

    1996-12-31

    Cold-cathode technology for Crossed-Field Amplifiers (CFAs) has not changed significantly over the last thirty years. The material typically used for cold cathode CFAs is either platinum (Pt) or beryllium (Be), although numerous other materials with higher secondary electron emission ratios have been tested. Beryllium cathodes display higher secondary emission ratios, {approximately} 3.4, than Pt, but require a partial pressure of oxygen to maintain a beryllium oxide (BeO) surface layer. These dispensers limit the life of the CFA, both directly, due to oxygen-source filament burnout, and indirectly, by the production of undesirable gases which adversely affect the performance of the CFA. In an attempt to reduce or eliminate the required oxygen dispenser output level, cathodes were constructed from three varieties of Be/BeO composite material and tested in L-4808s, standard forward-wave AEGIS CFAs. Diamond and diamond-like carbons are desirable as cathode materials because of their extremely high secondary electron emission ratio, greater than 20, but their use has previously been prohibitive because of cost, available, and physical characteristics. Because of recent advances in diamond growth technology it is now possible to deposit thin layers of diamond on a variety of geometric objects. In coordination with Penn State University four annular diamond emitters have been fabricated. The diamond emitters will be tested in a standard AEGIS CFA, both under vacuum and with a partial pressure of hydrogen.

  19. In vitro and in vivo evaluation of the bioactivity of hydroxyapatite-coated polyetheretherketone biocomposites created by cold spray technology.

    PubMed

    Lee, Jae Hyup; Jang, Hae Lin; Lee, Kyung Mee; Baek, Hae-Ri; Jin, Kyoungsuk; Hong, Kug Sun; Noh, Jun Hong; Lee, Hyun-Kyung

    2013-04-01

    Polyetheretherketone (PEEK) is a material that is widely used in medicine because its mechanical properties show excellent similarity to those of human bone. However, because it is bioinert, PEEK shows limited ability to bind to natural bone tissue. Here, we applied a cold spray method to make a hydroxyapatite (HA)-coated PEEK hybrid material and evaluated its osteointegration in vitro and in vivo. With the cold spray method, the HA coating formed a homogeneous layer and adhered strongly to the PEEK disk implant. When the material was tested in vitro, early cell adhesion and viability improved. Alkaline phosphatase (ALP) activity and calcium concentration were also higher in cells cultured on HA-coated PEEK disks. In addition, the expression of osteoblast differentiation markers, such as ALP, bone sialoprotein and runt-related transcription factor 2, increased in these cells. For the in vivo test, we designed and implanted HA-coated PEEK cylinders into a rabbit ilium model by the press-fit method. The bone-implant contact ratio, trabecular number and trabecular thickness were determined using either three-dimensional microcomputed tomography or general two-dimensional histomorphometric analysis. This report demonstrates that the HA coating on the PEEK implant added with the cold spray method increased biocompatibility in vitro and promoted osteointegration in vivo, which suggests that the HA coating may improve the biofunctionality of various medical devices used in clinical applications. PMID:23212079

  20. Structure and Mechanical Properties of Thick Copper Coating Made by Cold Spray

    NASA Astrophysics Data System (ADS)

    Maev, R. Gr.; Leshchynsky, V.; Strumban, E.; Dzhurinskiy, D.; Kocimski, J.; Maeva, E.

    2016-01-01

    The main purpose of this study was to form cold-sprayed copper coatings on A 516 low carbon steel, which is considered a prospective material for manufacturing used nuclear fuel containers. The 3 mm-thick Cu coatings were formed using the high pressure cold spray method with Nitrogen as the propellant gas. The deformation of copper particles during the deposition process was studied. The obtained SEM images of the Cu layer-A 516 low carbon steel substrate interface cross sections demonstrated that the Cu layer at the substrate interface had a dense microstructure with localized jet-metallic mixing areas. The Cu particles were deformed considerably more severely in this layer than in the consequently deposited upper layers. The steel substrate underwent severe deformation due to the impact of Cu particles. The mutual severe deformation of Cu particles and steel substrate resulted in a considerable increase of adhesion strength up to 120 MPa. The structure of coatings and coating-substrate interface was studied.

  1. Study of the laser marking process of cold sprayed titanium coatings on aluminium substrates

    NASA Astrophysics Data System (ADS)

    Astarita, A.; Genna, S.; Leone, C.; Memola Capece Minutolo, F.; Squillace, A.; Velotti, C.

    2016-09-01

    This paper deals with the study of the laser marking process of titanium cold sprayed coatings on aluminium substrates. Despite several studies regarding the laser marking process are available in literature very few attention have been paid to the marking of cold sprayed coatings and there are no previous papers in literature. Also the phenomena occurring during the marking of a porous coating are to date not fully understood and will be discussed in this paper. The experimental campaign was also repeated on grade 2 titanium rolled sheets with a thickness of 2 mm. The marking tests were carried out under different experimental conditions varying the main process parameters (i.e. laser pulse power and laser scan speed), after that the mark sections were observed by optical microscope and SEM. Both the maximum penetration depth and width of the marks were acquired and also internal damages induced by the process were studied. A correlation between the process parameters and the mark's geometry was found. The results show the effectiveness of the laser process to produce high quality marks on both the titanium layer and the titanium sheet. Moreover, a higher mark penetration on Ti coating was observed compared to the Ti sheet. However, the results show also the possibility to introduce severe and hidden damages in both materials if the process parameters are not properly set.

  2. Structural and Tribological Properties of Nanostructured Supersonic Cold Sprayed Ni-20 wt.% Sn Coatings

    NASA Astrophysics Data System (ADS)

    Georgiou, E. P.; Dosta, S.; Fernández, J.; Matteazzi, P.; Kowalski, K.; Kusinski, J.; Piticescu, R. R.; Celis, J.-P.

    2016-05-01

    80-μm-thick nanostructured coatings consisting of a Ni solid solution, Ni3Sn, Ni3Sn2, and metastable NiSn intermetallic phases were deposited via supersonic cold spraying onto inconel 718 alloy substrates. These coatings have complex nanostructured metallurgical phases as revealed by transition electron microscopy, scanning electron microscopy, and x-ray diffraction techniques. Their mechanical properties were determined by nanoindentation measurements. Furthermore, the wear behavior of these nanostructured sprayed coatings was compared to the one of the industrial bulk or sprayed coated benchmark materials. It was found that the nanostructured coatings exhibit higher wear resistance than the industrial benchmarks, thanks to an appropriate balance of hard intermetallic phases and soft Ni matrix, as well as to their nanostructuring. Their frictional characteristics under reciprocating sliding are mainly determined by the formation of an oxide-based tribo-layer, which was analyzed by x-ray photoelectron spectroscopy. The role of intermetallic phases in these coatings on the friction and wear is also discussed.

  3. Structural and Tribological Properties of Nanostructured Supersonic Cold Sprayed Ni-20 wt.% Sn Coatings

    NASA Astrophysics Data System (ADS)

    Georgiou, E. P.; Dosta, S.; Fernández, J.; Matteazzi, P.; Kowalski, K.; Kusinski, J.; Piticescu, R. R.; Celis, J.-P.

    2016-06-01

    80-μm-thick nanostructured coatings consisting of a Ni solid solution, Ni3Sn, Ni3Sn2, and metastable NiSn intermetallic phases were deposited via supersonic cold spraying onto inconel 718 alloy substrates. These coatings have complex nanostructured metallurgical phases as revealed by transition electron microscopy, scanning electron microscopy, and x-ray diffraction techniques. Their mechanical properties were determined by nanoindentation measurements. Furthermore, the wear behavior of these nanostructured sprayed coatings was compared to the one of the industrial bulk or sprayed coated benchmark materials. It was found that the nanostructured coatings exhibit higher wear resistance than the industrial benchmarks, thanks to an appropriate balance of hard intermetallic phases and soft Ni matrix, as well as to their nanostructuring. Their frictional characteristics under reciprocating sliding are mainly determined by the formation of an oxide-based tribo-layer, which was analyzed by x-ray photoelectron spectroscopy. The role of intermetallic phases in these coatings on the friction and wear is also discussed.

  4. Coating of High-Alloyed, Ledeburitic Cold Work Tool Steel Applied by HVOF Spraying

    NASA Astrophysics Data System (ADS)

    Rajasekaran, B.; Mauer, G.; Vassen, R.; Röttger, A.; Weber, S.; Theisen, W.

    2010-03-01

    This study demonstrates the processing of a cold work tool steel (X220CrVMo13-4) coating using HVOF spraying. The coating formation was analyzed based on microstructure, phase, hardness, porosity, oxidation, and adhesion characteristics. An online diagnostic tool was utilized to find out the in-flight characteristics of powder such as temperature and velocity during the coating process to identify the influencing parameters to achieve dense cold work tool steel coatings with low oxidation. The influence of powder size, process parameters, and in-flight characteristics on the formation of cold work tool steel coatings was demonstrated. The results indicated that thick and dense cold work tool steel coatings with low oxidation can be obtained by the selection of appropriate powder size and process parameters.

  5. Laser-Assisted Cold-Sprayed Corrosion- and Wear-Resistant Coatings: A Review

    NASA Astrophysics Data System (ADS)

    Olakanmi, E. O.; Doyoyo, M.

    2014-06-01

    Laser-assisted cold spray (LACS) process will be increasingly employed for depositing coatings because of its unique advantages: solid-state deposition of dense, homogeneous, and pore-free coatings onto a range of substrates; and high build rate at reduced operating costs without the use of expensive heating and process inert gases. Depositing coatings with excellent performance indicators via LACS demands an accurate knowledge and control of processing and materials' variables. By varying the LACS process parameters and their interactions, the functional properties of coatings can be manipulated. Moreover, thermal effect due to laser irradiation and microstructural evolution complicate the interpretation of LACS mechanical deformation mechanism which is essential for elucidating its physical phenomena. In order to provide a basis for follow-on-research that leads to the development of high-productivity LACS processing of coatings, this review focuses on the latest developments in depositing corrosion- and wear-resistant coatings with the emphasis on the composition, structure, and mechanical and functional properties. Historical developments and fundamentals of LACS are addressed in an attempt to describe the physics behind the process. Typical technological applications of LACS coatings are also identified. The investigations of all process sequences, from laser irradiation of the powder-laden gas stream and the substrate, to the impingement of thermally softened particles on the deposition site, and subsequent further processes, are described. Existing gaps in the literature relating to LACS-dependent microstructural evolution, mechanical deformation mechanisms, correlation between functional properties and process parameters, processing challenges, and industrial applications have been identified in order to provide insights for further investigations and innovation in LACS deposition of wear- and corrosion-resistant coatings.

  6. 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.

  7. B4C/Ni Composite Coatings Prepared by Cold Spray of Blended or CVD-Coated Powders

    NASA Astrophysics Data System (ADS)

    Feng, C.; Guipont, V.; Jeandin, M.; Amsellem, O.; Pauchet, F.; Saenger, R.; Bucher, S.; Iacob, C.

    2012-06-01

    In this work, the microstructures of B4C/Ni coatings by cold spray with blends or chemical vapor deposited (CVD) Ni-coated powders were investigated and compared. Powder blends with Ni powder and fine or coarse B4C powders were prepared for various B4C content ranging from 54 to 87 vol.% (equal to 25-65 wt.%). Three CVD Ni-coated B4C powder batches were also synthesized with various B4C content using the fine B4C as core particles. Ni-coated powders and both types of cold sprayed coating microstructures with blends or coated powders were investigated by optical and scanning electron microscopy. Further quantitative image analysis was carried out on scanning electron microscopy (SEM) images to measure the B4C content within the coating regarding the influence of the nominal content in the feedstock for each coating type. Both types exhibited fine fragments and unfragmented B4C, but coatings with CVD-coated powders had many more unfragmented particles. Moreover, the higher levels for both B4C (44.0 ± 4.1 vol.%) and coating microhardness (429 ± 41 HV0.5) were obtained in case of the CVD-coated powders. However, it was assessed that the highest microhardness was not obtained for the highest B4C content. This questionable result is discussed with regard to the fully original composite microstructure obtained from CVD Ni-coated B4C powder.

  8. Comparative High-Temperature Corrosion Behavior of Ni-20Cr Coatings on T22 Boiler Steel Produced by HVOF, D-Gun, and Cold Spraying

    NASA Astrophysics Data System (ADS)

    Kaushal, Gagandeep; Bala, Niraj; Kaur, Narinder; Singh, Harpreet; Prakash, Satya

    2014-01-01

    To protect materials from surface degradations such as wear, corrosion, and thermal flux, a wide variety of materials can be deposited on the materials by several spraying processes. This paper examines and compares the microstructure and high-temperature corrosion of Ni-20Cr coatings deposited on T22 boiler steel by high velocity oxy-fuel (HVOF), detonation gun spray, and cold spraying techniques. The coatings' microstructural features were characterized by means of XRD and FE-SEM/EDS analyses. Based upon the results of mass gain, XRD, and FE-SEM/EDS analyses it may be concluded that the Ni-20Cr coating sprayed by all the three techniques was effective in reducing the corrosion rate of the steel. Among the three coatings, D-gun spray coating proved to be better than HVOF-spray and cold-spray coatings.

  9. Residual Stress Analysis of Cold-Sprayed Copper Coatings by Numerical Simulation

    NASA Astrophysics Data System (ADS)

    Li, Wenya; Yang, Kang; Zhang, Dongdong; Zhou, Xianglin

    2016-01-01

    In this paper, an analysis on the residual stress evolution of cold-sprayed copper coatings on Cu and Al substrates was performed. To investigate the influences of particle velocity, temperature and material combination on the final residual stresses, an integrated frame of calculation was proposed based on the simulation results obtained from the developed thermo-mechanically coupled Eulerian model. In a single Cu splat, generally speaking, the maximum residual stress and plastic deformation are concentrated at the outside contact zone rather than at the center point of initial impact. The action of friction shear between the particle and substrate during impacting should be considered as one of the essential factors on the final residual stress. And the states of residual stresses can vary significantly depending on the material combination, particle velocity, and temperature. In a single pass Cu coating, the residual stress fluctuates across the coating and there exists both compressive stress and tensile stress within the coating. At a certain range of impacting velocities, the resultant residual stresses increase with the increase of particle velocity. The present simulated results are related to the reported experiments by others, showing that the residual stress states and stress change trend are different from some of the reported results.

  10. Space Environmental Effects on Coated Tether Materials

    NASA Technical Reports Server (NTRS)

    Gittemeier, Keith A.; Hawk, Clark W.; Finckenor, Miria M.; Watts, Ed

    2005-01-01

    The University of Alabama in Huntsville s Propulsion Research Center has teamed with NASA's Marshall Space Flight Center (MSFC) to research the effects of atomic oxygen (AO) bombardment on coated tether materials. Tethers Unlimited Inc. has provided several candidate tether materials with various coatings for AO exposure in MSFC s Atomic Oxygen Beam Facility. Additional samples were exposed to ultraviolet (UV) radiation at MSFC. AO erodes most organic materials, and ultraviolet radiation embrittles polymers. This test series was performed to determine the effect of AO and UV on the mechanical integrity of tether materials that were treated with AO-protective coatings, such as polyhedral oligomeric silsesquioxane (POSS) or metallization. Both TUI's Multi-Application Survivable Tether (MAST) Experiment and Marshall Space Flight Center s Momentum Exchange Electrodynamic Reboost (MXER) programs will benefit from this research by helping to determine tether materials and coatings that give the longest life with the lowest mass penalty.

  11. Atomic Oxygen Effects on Coated Tether Materials

    NASA Technical Reports Server (NTRS)

    Gittemeier, Keith A.; Hawk, Clark W.; Finckenor, Miria M.; Watts, Ed

    2005-01-01

    The University of Alabama in Huntsville s Propulsion Research Center has teamed with NASA's Marshall Space Flight Center (MSFC) to research the effects of atomic oxygen (AO) bombardment on coated tether materials. Tethers Unlimited Inc. has provided several candidate tether materials with various coatings for (AO) exposure in MSFC's Atomic Oxygen Beam Facility. Additional samples were exposed to ultraviolet (UV) radiation at MSFC. AO erodes most organic materials, and ultraviolet radiation embrittles polymers. This test series was performed to determine the effect of AO and UV on the mechanical integrity of tether materials that were treated with AO-protective coatings, such as Photosil or metallization. Both TUI's Multi-Application Survivable Tether (MAST) Experiment and Marshall Space Flight Center's Momentum Exchange Electrodynamic Reboost (MXER) programs will benefit from this research by helping to determine tether materials and coatings that give the longest life with the lowest mass penalty.

  12. Electromagnetic properties of material coated surfaces

    NASA Technical Reports Server (NTRS)

    Beard, L.; Berrie, J.; Burkholder, R.; Dominek, A.; Walton, E.; Wang, N.

    1989-01-01

    The electromagnetic properties of material coated conducting surfaces were investigated. The coating geometries consist of uniform layers over a planar surface, irregularly shaped formations near edges and randomly positioned, electrically small, irregularly shaped formations over a surface. Techniques to measure the scattered field and constitutive parameters from these geometries were studied. The significance of the scattered field from these geometries warrants further study.

  13. Photocatalytic abatement of NOx by C-TiO2/polymer composite coatings obtained by low pressure cold gas spraying

    NASA Astrophysics Data System (ADS)

    Robotti, M.; Dosta, S.; Fernández-Rodríguez, C.; Hernández-Rodríguez, M. J.; Cano, I. G.; Melián, E. Pulido; Guilemany, J. M.

    2016-01-01

    In the present work, we study the photocatalytic activity of carbon-modified TiO2 (C-TiO2)/polymer composite coatings obtained by low pressure cold gas spraying (LP-CGS). To produce the novel coatings, C-TiO2 was mixed with a ductile material, the polymer ECTFE, by means of a low energy ball milling (LEBM) process. The LEBM system permits the mechanical anchoring of small TiO2 aggregates around the large ductile polymeric particles. A well-bonded coating with good mechanical coupling was formed between the ball-milled mixture and the substrate. Photocatalytic tests showed that the LP-CGS nano-TiO2 coatings actively photodegraded NO and the by-product, NO2. Compared to commercial paint, the as-prepared coatings presented here enhanced photocatalytic performance.

  14. Significant influence of particle surface oxidation on deposition efficiency, interface microstructure and adhesive strength of cold-sprayed copper coatings

    NASA Astrophysics Data System (ADS)

    Li, Wen-Ya; Li, Chang-Jiu; Liao, Hanlin

    2010-06-01

    The critical velocity for particle deposition in cold spraying is a key parameter, which depends not only on the material type, but also the particle temperature and oxidation condition. The dependency of deposition efficiency of cold spray Cu particles on the particle temperature and surface oxidation was examined. The effect of particle surface oxide scales on the interfacial microstructure and adhesive strength of the cold-sprayed Cu coatings was investigated. The results show that the deposition efficiency significantly increases with increasing the gas temperature but decreases with augmenting the oxygen content of the starting powder. The oxide inclusions at the interfaces between the deposited particles inhibit the effective bonding of fresh metals and remarkably lower the bond strength of the deposited Cu coatings on steel.

  15. Optical mirror coated with organic superconducting material

    NASA Astrophysics Data System (ADS)

    Lake, John A.; Heath, William B.

    1988-08-01

    An optical mirror has enhanced reflectivity and reduced thermal distortions when it is composed of a substrate coated with a reflective coating made of an organic superconducting material. The substrate is best constructed of materials which have the most favorable thermal expansion and thermal conduction characteristics at temperatures near 0 K. such as: silicon, diamond, copper, and sapphire. The reflective coating is only a few microns thick and composed of organometallic compounds and is cooled to superconducting or cryogenic temperatures of less than 100 K.

  16. Corrosion protective coating for metallic materials

    DOEpatents

    Buchheit, R.G.; Martinez, M.A.

    1998-05-26

    Corrosion protective coatings for metallic materials, particularly aluminum and aluminum alloys, produced with simple, low-cost equipment and materials other than toxic metals or metal salts, or metal cyanides is disclosed. The metallic material is cleaned, degreased, and deoxidized, the surface is converted to a substantially alkaline condition, and the surface is chemically sealed with inorganic metal compounds. 1 fig.

  17. Corrosion protective coating for metallic materials

    DOEpatents

    Buchheit, Rudolph G.; Martinez, Michael A.

    1998-01-01

    Corrosion protective coatings for metallic materials, particularly aluminum and aluminum alloys, produced with simple, low-cost equipment and materials other than toxic metals or metal salts, or metal cyanides. The metallic material is cleaned, degreased, and deoxidized, the surface is converted to a substantially alkaline condition, and the surface is chemically sealed with inorganic metal compounds.

  18. Biocatalytic material comprising multilayer enzyme coated fiber

    DOEpatents

    Kim, Jungbae [Richland, WA; Kwak, Ja Hun [Richland, WA; Grate, Jay W [West Richland, WA

    2009-11-03

    The present invention relates generally to high stability, high activity biocatalytic materials and processes for using the same. The materials comprise enzyme aggregate coatings having high biocatalytic activity and stability useful in heterogeneous environment. These new materials provide a new biocatalytic immobilized enzyme system with applications in bioconversion, bioremediation, biosensors, and biofuel cells.

  19. Development of Oxidation Resistant Coatings on GRCop-84 Substrates by Cold Spray Process

    NASA Technical Reports Server (NTRS)

    Karthikeyan, J.

    2007-01-01

    GRCop-84, a Cu-CR-Nb alloy, has been developed for rocket engine liner applications. For maximum life additional oxidation protection is required to prevent blanching. NiCrAlY was identified as a suitable coating, and efforts were initiated to develop suitable coating techniques. Cold spray is one technique under consideration. Efforts at ASB Industries to produce dense, adherent coatings are detailed. The work culminated in the production of samples for testing at NASA Glenn Research Center.

  20. Hot Corrosion Behavior of Cold-Sprayed Ni-50Cr Coating in an Incinerator Environment at 900 °C

    NASA Astrophysics Data System (ADS)

    Singh, Harminder; Sidhu, T. S.; Kalsi, S. B. S.; Karthikeyan, J.

    2015-02-01

    In the present study, 50%Ni-50%Cr coating was developed on Superni 75 superalloy by a novel and facile cold-spray coating deposition technique. Dense, adhered, and oxide-free cold-sprayed coating was obtained in this study. This coating effectively provided corrosion protection to the substrate in real service incinerator conditions at 900 °C. The corrosion rate of the coated alloy was 0.47 mm/year, compared with 1.04 mm/year for bare alloy. This study indicates that the cold-spray process is an effective alternative for depositing high-temperature corrosion-resistant coatings.

  1. Effect of Heat Treatment on Mechanical Properties and Corrosion Performance of Cold-Sprayed Tantalum Coatings

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Vidyasagar, V.; Jyothirmayi, A.; Joshi, S. V.

    2016-04-01

    The cold-spray technique is of significant interest to deposit refractory metals with relatively high melting point for a variety of demanding applications. In the present study, mechanical properties of cold-sprayed tantalum coatings heat treated at different temperatures were investigated using microtensile testing, scratch testing, and nanoindentation. The corrosion performance of heat-treated coatings was also evaluated in 1 M KOH solution, and potentiodynamic polarization as well as impedance spectroscopy studies were carried out. Assessment of structure-property correlations was attempted based on microstructure, porosity, and intersplat bonding state, together with mechanical and corrosion properties of the heat-treated cold-sprayed tantalum coatings. Coatings annealed at 1500 °C, which is very close to the recrystallization temperature of tantalum, were found to perform almost as bulk tantalum, with exciting implications for various applications.

  2. Effect of Nozzle Material on Downstream Lateral Injection Cold Spray Performance

    NASA Astrophysics Data System (ADS)

    MacDonald, D.; Leblanc-Robert, S.; Fernández, R.; Farjam, A.; Jodoin, B.

    2016-06-01

    In cold gas dynamic spraying, the gas nature, process stagnation pressure and temperature, and the standoff distance are known to be important parameters that affect the deposition efficiency and coating quality. This investigation attempts to elucidate the effect of nozzle material on coatings produced using a downstream lateral injection cold spray system. Through experimentation, it is shown that the nozzle material has a substantial effect on deposition efficiency and particle velocity. It is proposed that the effects are related to complex interaction between the particles and the internal nozzle walls. The results obtained lead to the conclusion that during the particle/nozzle wall contact, a nozzle with higher thermal diffusivity transfers more heat to the particles. This heat transfer results in lower critical velocities and therefore higher deposition efficiencies, despite a noticeable reduction of particle velocities which is also attributed to particle-nozzle interactions.

  3. Effect of Nozzle Material on Downstream Lateral Injection Cold Spray Performance

    NASA Astrophysics Data System (ADS)

    MacDonald, D.; Leblanc-Robert, S.; Fernández, R.; Farjam, A.; Jodoin, B.

    2016-08-01

    In cold gas dynamic spraying, the gas nature, process stagnation pressure and temperature, and the standoff distance are known to be important parameters that affect the deposition efficiency and coating quality. This investigation attempts to elucidate the effect of nozzle material on coatings produced using a downstream lateral injection cold spray system. Through experimentation, it is shown that the nozzle material has a substantial effect on deposition efficiency and particle velocity. It is proposed that the effects are related to complex interaction between the particles and the internal nozzle walls. The results obtained lead to the conclusion that during the particle/nozzle wall contact, a nozzle with higher thermal diffusivity transfers more heat to the particles. This heat transfer results in lower critical velocities and therefore higher deposition efficiencies, despite a noticeable reduction of particle velocities which is also attributed to particle-nozzle interactions.

  4. Stand for coating deposition and coating/materials testing

    NASA Astrophysics Data System (ADS)

    Ayrapetov, A. A.; Begrambekov, L. B.; Dyachenko, M. Yu; Evsin, A. E.; Grunin, A. V.; Kalachev, A. M.; Sadovskiy, Ya A.; Shigin, P. A.

    2016-03-01

    The paper describes a new laboratory stand constructed for film deposition and for testing of deposited films and materials under pulsed and continuous heat load, ion and electron irradiation. The films are formed on substrates by atoms of target materials as a result of their sputtering by ions of argon plasma. The ion energy and ion flux can be varied independently. This enables the deposition of coatings with variable composition over thickness or of multi-layer coatings. Testing of materials is carried out in plasma under ion or electron irradiation by biasing the tested sample negatively or positively, respectively. The energies of ions or electrons can be varied up to 25 keV. The applied power can reach 4000 W (40 MW/m2 power density in the case of a 1-cm2 sample) in both continuous and pulsed regimes. In pulsed regime, pulses of 1 – 99% duty cycle at 0 – 500 Hz can be applied to the sample. The pulsed particle load can be combined with a continuous load. The size of the tested sample must not exceed 100 mm in diameter. The heat flux can irradiate the whole sample or be focused at its center (minimum spot of ~ 4mm2). Heating of the samples up to 2800 K is possible. At the same time, the backside of the tested sample could be actively cooled. This paper presents the results of deposition and testing of a B4C coating on tungsten and tungsten testing.

  5. Numerical and Experimental Investigation of Cold Spray Gas Dynamic Effects for Polymer Coating

    NASA Astrophysics Data System (ADS)

    Alhulaifi, Abdulaziz S.; Buck, Gregory A.; Arbegast, William J.

    2012-09-01

    Low melting temperature materials such as polymers are known to be difficult to deposit using traditional cold spray techniques. Computational fluid dynamics (CFD) models were created for various nozzle geometries and flow conditions. A schlieren optical system was used to visualize the density gradients and flow characteristics in the free jet impingement region. Based on the CFD models, it was determined that a diffuser placed into the carrier gas flow near the nozzle exit not only leads to lower particle impact velocity required for polymer deposition, but also provides for appropriate application of compression heating of the particles to produce the conditions necessary at impact for successful coating adhesion of these materials. Experiments subsequently confirmed the successful deposition of polyethylene powder onto a 7075-T6 aluminum substrate. Using air as the carrier gas, polyethylene particles of 53-75 μm diameter and 0.94 g/cm3 density, were cold spray deposited onto the aluminum substrate, with a critical impact velocity of 191 m/s. No apparent melting of the polymer particles was observed. Refinements to these concepts are currently under investigation and a patent disclosure for the idea is pending.

  6. Alloying of cold-sprayed Al Ni composite coatings by post-annealing

    NASA Astrophysics Data System (ADS)

    Lee, Ha Yong; Jung, Se Hun; Lee, Soo Yong; Ko, Kyung Hyun

    2007-01-01

    A new cold spray coating technique for thick Al coating with finely dispersed Al-Ni intermetallic compounds was tested. For easy powder preparation and high yield, rather than using of Al/compound mixture feed stock, the spraying of pure Al and Ni powders mixture followed by post-annealing was suggested. The powder composition of Al and Ni was 75:25, and 90:10 (wt.%) to expect full consumption of pure Ni into intermetallic compounds. After Al-Ni composite coatings, the Ni particles were finely dispersed and embedded in the Al matrix with a good coating yield. Above 450 °C of post-annealing temperature, the Al 3Ni and Al 3Ni 2 phases were observed in the cold-sprayed Al-Ni coatings. The Ni particles in the Al matrix were fully consumed via compounding reaction with Al at 550 °C of the annealing temperature.

  7. Methods of Antimicrobial Coating of Diverse Materials

    NASA Technical Reports Server (NTRS)

    Akse, James R.; Holtsnider, John T.; Kliestik, Helen

    2011-01-01

    Methods of coating diverse substrate materials with antimicrobial agents have been developed. Originally intended to reduce health risks to astronauts posed by pathogenic microorganisms that can grow on surfaces in spacecraft, these methods could also be used on Earth for example, to ensure sterility of surgical inserts and other medical equipment. The methods involve, generally, chemical preparation of substrate surfaces to enable attachment of antimicrobial molecules to the substrate surfaces via covalent bonds. Substrate materials that have been treated successfully include aluminum, glass, a corrosion-resistant nickel alloy, stainless steel, titanium, and poly(tetrafluoroethylene). Antimicrobial agents that have been successfully immobilized include antibiotics, enzymes, bacteriocins, bactericides, and fungicides. A variety of linkage chem istries were employed. Activity of antimicrobial coatings against gram-positive bacteria, gram-negative bacteria, and fungi was demonstrated. Results of investigations indicate that the most suitable combination of antimicrobial agent, substrate, and coating method depends upon the intended application.

  8. Metal Matrix Composite Coatings Fabricated by Low-Pressure Cold Gas Dynamic Spraying

    NASA Astrophysics Data System (ADS)

    Hodder, K. J.; Nychka, J. A.; McDonald, A. G.

    2014-06-01

    Cold-gas dynamic spraying ("cold spraying") was used to deposit aluminum-alumina (Al-Al2O3) metal-matrix composite (MMC) coatings onto 6061 Al alloy. The powders consisted of -45 μm commercially pure Al that was admixed with either 10 μm or agglomerated 20 nm Al2O3 in weight fractions of 25, 50, 75, 90, and 95 wt.%. Scanning electron microscopy (SEM), Vickers microhardness testing, and image analysis were conducted to determine the microstructure, properties, and the volume fractions of reinforcing particles in the coatings, which was then converted to weight fractions. As the weight fraction of the Al2O3 in the coatings increased, the hardness values of the MMC coatings increased. A maximum hardness of 96 ± 10 HV0.2 was observed for the MMC coating that contained the agglomerated 20 nm Al2O3 particles, while a maximum hardness of 85 ± 24 HV0.2 was observed for the coatings with the 10 μm Al2O3 particles. The slight increase in hardness of the coating containing the agglomerated 20 nm Al2O3 particles occurred in a coating of Al2O3 content that was lower than that in the coating that contained the 10 μm reinforcing Al2O3 particles. The increased hardness of the MMC coatings that contained the agglomerated 20 nm Al2O3 particles and at lower reinforcing particle content was attributed to the increased spreading of the nanoagglomerated particles in the coating, which increased load-sharing and reinforcement capability of the particles. These results suggest that the use of nanoagglomerated, reinforcing hard-phase particles in cold-sprayed MMC coatings may be a more efficient alternative to the use of conventional micronsized reinforcing particles.

  9. Erosion testing of hard materials and coatings

    SciTech Connect

    Hawk, Jeffrey A.

    2005-04-29

    Erosion is the process by which unconstrained particles, usually hard, impact a surface, creating damage that leads to material removal and component failure. These particles are usually very small and entrained in fluid of some type, typically air. The damage that occurs as a result of erosion depends on the size of the particles, their physical characteristics, the velocity of the particle/fluid stream, and their angle of impact on the surface of interest. This talk will discuss the basics of jet erosion testing of hard materials, composites and coatings. The standard test methods will be discussed as well as alternative approaches to determining the erosion rate of materials. The damage that occurs will be characterized in genera1 terms, and examples will be presented for the erosion behavior of hard materials and coatings (both thick and thin).

  10. Hydroxyapatite-Coated Magnesium-Based Biodegradable Alloy: Cold Spray Deposition and Simulated Body Fluid Studies

    NASA Astrophysics Data System (ADS)

    Noorakma, Abdullah C. W.; Zuhailawati, Hussain; Aishvarya, V.; Dhindaw, B. K.

    2013-10-01

    A simple modified cold spray process in which the substrate of AZ51 alloys were preheated to 400 °C and sprayed with hydroxyapatite (HAP) using high pressure cold air nozzle spray was designed to get biocompatible coatings of the order of 20-30 μm thickness. The coatings had an average modulus of 9 GPa. The biodegradation behavior of HAP-coated samples was tested by studying with simulated body fluid (SBF). The coating was characterized by FESEM microanalysis. ICPOES analysis was carried out for the SBF solution to know the change in ion concentrations. Control samples showed no aluminum corrosion but heavy Mg corrosion. On the HAP-coated alloy samples, HAP coatings started dissolving after 1 day but showed signs of regeneration after 10 days of holding. All through the testing period while the HAP coating got eroded, the surface of the sample got deposited with different apatite-like compounds and the phase changed with course from DCPD to β-TCP and β-TCMP. The HAP-coated samples clearly improved the biodegradability of Mg alloy, attributed to the dissolution and re-precipitation of apatite showed by the coatings as compared to the control samples.

  11. Weightless Environment Training Facility (WETF) materials coating evaluation, volume 2

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This volume consists of Appendices A and B to the report on the Weightless Environment Training Facility Materials Coating Evaluation project. The project selected 10 coating systems to be evaluated in six separate exposure environments, and subject to three tests for physical properties. Appendix A holds the coating system, surface preparation, and application data. Appendix B holds the coating material infrared spectra.

  12. Development of Erosion-Corrosion-Resistant Cold-Spray Nanostructured Ni-20Cr Coating for Coal-Fired Boiler Applications

    NASA Astrophysics Data System (ADS)

    Kumar, M.; Singh, H.; Singh, N.; Chavan, N. M.; Kumar, S.; Joshi, S. V.

    2015-12-01

    The erosion-corrosion (E-C) behavior of a cold-spray nanostructured Ni-20Cr coating was studied under cyclic conditions in a coal-fired boiler. This study was done for 15 cycles (1500 h), in which each cycle comprised 100 h of heating in the boiler environment, followed by 1 h of cooling under ambient air conditions. The E-C extent was evaluated in terms of thickness loss data of the samples. The eroded-corroded samples were characterized using XRD, SEM/EDS, and x-ray mapping analyses. The nanostructured coating offered excellent E-C protection to boiler tube material (SA 516 steel) under harsh live conditions of the boiler. This E-C resistance offered by investigated coating may be attributed to the presence of protective NiO and Cr2O3 phases in its oxide scale and its superior as-sprayed microhardness.

  13. Sprayable Phase Change Coating Thermal Protection Material

    NASA Technical Reports Server (NTRS)

    Richardson, Rod W.; Hayes, Paul W.; Kaul, Raj

    2005-01-01

    NASA has expressed a need for reusable, environmentally friendly, phase change coating that is capable of withstanding the heat loads that have historically required an ablative thermal insulation. The Space Shuttle Program currently relies on ablative materials for thermal protection. The problem with an ablative insulation is that, by design, the material ablates away, in fulfilling its function of cooling the underlying substrate, thus preventing the insulation from being reused from flight to flight. The present generation of environmentally friendly, sprayable, ablative thermal insulation (MCC-l); currently use on the Space Shuttle SRBs, is very close to being a reusable insulation system. In actual flight conditions, as confirmed by the post-flight inspections of the SRBs, very little of the material ablates. Multi-flight thermal insulation use has not been qualified for the Space Shuttle. The gap that would have to be overcome in order to implement a reusable Phase Change Coating (PCC) is not unmanageable. PCC could be applied robotically with a spray process utilizing phase change material as filler to yield material of even higher strength and reliability as compared to MCC-1. The PCC filled coatings have also demonstrated potential as cryogenic thermal coatings. In experimental thermal tests, a thin application of PCC has provided the same thermal protection as a much thicker and heavier application of a traditional ablative thermal insulation. In addition, tests have shown that the structural integrity of the coating has been maintained and phase change performance after several aero-thermal cycles was not affected. Experimental tests have also shown that, unlike traditional ablative thermal insulations, PCC would not require an environmental seal coat, which has historically been required to prevent moisture absorption by the thermal insulation, prevent environmental degradation, and to improve the optical and aerodynamic properties. In order to reduce

  14. Microstructure, microhardness and dry friction behavior of cold-sprayed tin bronze coatings

    NASA Astrophysics Data System (ADS)

    Guo, Xueping; Zhang, Ga; Li, Wen-Ya; Dembinski, Lucas; Gao, Yang; Liao, Hanlin; Coddet, Christian

    2007-12-01

    In this paper, two types of tin bronze coatings (Cu-6 wt.% Sn and Cu-8 wt.% Sn) were prepared by cold spray process. The as-sprayed coatings were subjected to a vacuum heat treatment at 600 °C for 3 h. The coating microstructure, microhardness and tribological performance were characterized. The effects of the tin content and the vacuum heat treatment on the microstructure, microhardness and tribological behavior of the coatings were investigated. It is found that the as-sprayed CuSn6 (As6) and CuSn8 (As8) coatings exhibit practically an identical porosity. Meanwhile, As8 presents a higher microhardness than As6. In addition, the increase of the tin content in the powder feedstock leads to a lower wear rate. After a heat treatment, coating porosities are significantly reduced. However, the coating hardness is significantly decreased and the coating presents a much decreased wear resistance. For the as-sprayed coatings, such factors as ploughing and particle delamination could determine the sliding process. The heat treatment results in a distinct modification of the tribological behavior. For the annealed coatings, the adhesion, between the coating and the counterpart, could play a dominant role in the sliding process.

  15. The Use of Particle/Substrate Material Models in Simulation of Cold-Gas Dynamic-Spray Process

    NASA Astrophysics Data System (ADS)

    Rahmati, Saeed; Ghaei, Abbas

    2014-02-01

    Cold spray is a coating deposition method in which the solid particles are accelerated to the substrate using a low temperature supersonic gas flow. Many numerical studies have been carried out in the literature in order to study this process in more depth. Despite the inability of Johnson-Cook plasticity model in prediction of material behavior at high strain rates, it is the model that has been frequently used in simulation of cold spray. Therefore, this research was devoted to compare the performance of different material models in the simulation of cold spray process. Six different material models, appropriate for high strain-rate plasticity, were employed in finite element simulation of cold spray process for copper. The results showed that the material model had a considerable effect on the predicted deformed shapes.

  16. Antibacterial Property of Cold-Sprayed HA-Ag/PEEK Coating

    NASA Astrophysics Data System (ADS)

    Sanpo, Noppakun; Tan, Meng Lu; Cheang, Philip; Khor, K. A.

    2009-03-01

    The antibacterial behavior of HA-Ag (silver-doped hydroxyapatite) nanopowder and their composite coatings were investigated against Escherichia coli (DH5α). HA-Ag nanopowder and PEEK (poly-ether-ether-ketone)-based HA-Ag composite powders were synthesized using in-house powder processing techniques. Bacteria culture assay of HA-Ag nanopowder and their composite powders displayed excellent bacteriostatic activity against E. coli. The antibacterial activity increased with increasing concentration of HA-Ag nanoparticle in these composite powders. These nanocomposite powders were subsequently used as feedstock to generate antibacterial coatings via cold spray technology. The ratios of HA-Ag to PEEK in their composite powders were 80:20, 60:40, 40:60, and 20:80 (wt.%). Microstructural characterization and phase analysis of feedstock powders and as-deposited coatings were carried out using FESEM/EDX and XRD. Antibacterial nanocomposite HA-Ag/PEEK coatings were successfully deposited using cold spraying parameters of 11-12 bars at preheated air temperature between 150 and 160 °C. These as-sprayed coatings of HA-Ag/PEEK composite powders comprising varying HA-Ag and PEEK ratios retained their inherent antibacterial property as verified from bacterial assay. The results indicated that the antibacterial activity increased with increasing HA-Ag nanopowder concentration in the composite powder feedstock and cold-sprayed coating.

  17. Characterization of Cold-Sprayed IN625 and NiCr Coatings

    NASA Astrophysics Data System (ADS)

    Srinivasan, Dheepa; Chandrasekhar, Vighnesh; Amuthan, Ramar; Lau, Y. C.; Calla, Eklavya

    2016-04-01

    Ni-based coatings IN625® and Ni20%Cr were cold sprayed on a low-alloy steel (AISI 4130) substrate, using Helium as the process gas. Dense coatings up to 3-mm thickness were deposited, having a hardness of 500-550 HV. The coatings showed a hardness maximum, with heat treatment, before dropping to a lower value. The coating microstructure revealed two distinct types of regions, comprising grains with a high dislocation density and elongated shear bands having twins. Heat treatment led to 30-50 nm grains in the IN625 coating, and >1-2 μm grains for NiCr. Both coatings showed a compressive residual stress in the as-sprayed condition, which relaxed to a zero residual stress, at 650 °C. The NiCr coatings showed a much higher compressibility, as compared to IN625. The IN625 coatings induced a much larger deformation on the 4130 steel. Overall, while both types of Ni-based alloy coatings showed similarities in terms of hardness and microstructure, they revealed distinct differences in their deformability, thermal stability, and substrate deformation, indicating a different behavior between a binary solid solution (NiCr) as compared to a multielement solid solution (IN625), as elucidated via a detailed characterization of these coatings.

  18. 21 CFR 872.3310 - Coating material for resin fillings.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Coating material for resin fillings. 872.3310... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3310 Coating material for resin fillings. (a) Identification. A coating material for resin fillings is a device intended to be applied to...

  19. 21 CFR 872.3310 - Coating material for resin fillings.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Coating material for resin fillings. 872.3310... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3310 Coating material for resin fillings. (a) Identification. A coating material for resin fillings is a device intended to be applied to...

  20. 21 CFR 872.3310 - Coating material for resin fillings.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Coating material for resin fillings. 872.3310... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3310 Coating material for resin fillings. (a) Identification. A coating material for resin fillings is a device intended to be applied to...

  1. 21 CFR 872.3310 - Coating material for resin fillings.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Coating material for resin fillings. 872.3310... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3310 Coating material for resin fillings. (a) Identification. A coating material for resin fillings is a device intended to be applied to...

  2. 21 CFR 872.3310 - Coating material for resin fillings.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Coating material for resin fillings. 872.3310... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3310 Coating material for resin fillings. (a) Identification. A coating material for resin fillings is a device intended to be applied to...

  3. An innovative getter coating for IR dewars and cold shields

    NASA Astrophysics Data System (ADS)

    Katsir, Dina; Feinman, Daniel

    2008-04-01

    A new getter type produced as a vacuum deposited thin-film is under development (patent pending). The film serves as an efficient pumping substance and also as an efficient absorber of IR stray light. The getter film is activated in place by heating to 130 °C. The film is very thin and has excellent vibration resistance and temperature stability and is expected to serve as an advantageous new solution for IR detector dewars and cold shields.

  4. Nanostructural Characteristics of Vacuum Cold-Sprayed Hydroxyapatite/Graphene-Nanosheet Coatings for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Huang, Jing; Li, Hua

    2014-10-01

    Development of novel biocompatible nanomaterials has provided insights into their potential biomedical applications. Bulk fabrication of the nanomaterials in the form of coatings remains challenging. Here, we report hydroxyapatite (HA)/graphene-nanosheet (GN) composite coatings deposited by vacuum cold spray (VCS). Significant shape changes of HA nanograins during the coating deposition were revealed. The nanostructural features of HA together with curvature alternation of GN gave rise to dense structures. Based on the microstructural characterization, a structure model was proposed to elucidate the nanostructural characteristics of the HA-GN nanocomposites. Results also showed that addition of GN significantly enhanced fracture toughness and elastic modulus of the HA-based coatings, which is presumably accounted for by crack bridging offered by GN in the composites. The VCS HA-GN coatings show potential for biomedical applications for the repair or replacement of hard tissues.

  5. Cyclic Oxidation Behavior of CuCrAl Cold-Sprayed Coatings for Reusable Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Raj, Sai; Karthikeyan, J.

    2009-01-01

    The next generation of reusable launch vehicles is likely to use GRCop-84 [Cu-8(at.%)Cr-4%Nb] copper alloy combustion liners. The application of protective coatings on GRCop-84 liners can minimize or eliminate many of the environmental problems experienced by uncoated liners and significantly extend their operational lives and lower operational cost. A newly developed Cu- 23 (wt.%) Cr-5% Al (CuCrAl) coating, shown to resist hydrogen attack and oxidation in an as-cast form, is currently being considered as a protective coating for GRCop-84. The coating was deposited on GRCop-84 substrates by the cold spray deposition technique, where the CuCrAl was procured as gas-atomized powders. Cyclic oxidation tests were conducted between 773 and 1,073 K to characterize the coated substrates.

  6. Mechanical and wear properties of aluminum coating prepared by cold spraying

    SciTech Connect

    Yusof, Siti Nurul Akmal Manap, Abreeza Afandi, Nurfanizan Mohd; Salim, Musdalilah; Misran, Halina

    2015-07-22

    In this study, aluminum (Al) powders were deposited onto Al substrates using cold spray to form a coating. The main objective is to investigate and compare the microstructure, mechanical and wear properties of Al coating to that of the Al substrate. The microstructure of the coating and substrate were observed using Scanning Electron Microscope (SEM). Hardness was evaluated using the Vickers Hardness test and wear properties were investigated using a pin-on-disk wear test machine. The elemental composition of the coating and substrate was determined using Energy-dispersive X-ray spectroscopy (EDX). Results showed that the friction coefficient and specific wear rate decreased while wear rate increased linearly with increasing load. It was found that the coating exhibit slightly better mechanical and wear properties compared to the substrate.

  7. Conductive Carbon Coatings for Electrode Materials

    SciTech Connect

    Doeff, Marca M.; Kostecki, Robert; Wilcox, James; Lau, Grace

    2007-07-13

    A simple method for optimizing the carbon coatings on non-conductive battery cathode material powders has been developed at Lawrence Berkeley National Laboratory. The enhancement of the electronic conductivity of carbon coating enables minimization of the amount of carbon in the composites, allowing improvements in battery rate capability without compromising energy density. The invention is applicable to LiFePO{sub 4} and other cathode materials used in lithium ion or lithium metal batteries for high power applications such as power tools and hybrid or plug-in hybrid electric vehicles. The market for lithium ion batteries in consumer applications is currently $5 billion/year. Additionally, lithium ion battery sales for vehicular applications are projected to capture 5% of the hybrid and electric vehicle market by 2010, and 36% by 2015 (http://www.greencarcongress.com). LiFePO{sub 4} suffers from low intrinsic rate capability, which has been ascribed to the low electronic conductivity (10{sup -9} S cm{sup -1}). One of the most promising approaches to overcome this problem is the addition of conductive carbon. Co-synthesis methods are generally the most practical route for carbon coating particles. At the relatively low temperatures (<800 C) required to make LiFePO{sub 4}, however, only poorly conductive disordered carbons are produced from organic precursors. Thus, the carbon content has to be high to produce the desired enhancement in rate capability, which decreases the cathode energy density.

  8. Coating materials for fusion application in China

    NASA Astrophysics Data System (ADS)

    Luo, G.-N.; Li, Q.; Liu, M.; Zheng, X. B.; Chen, J. L.; Guo, Q. G.; Liu, X.

    2011-10-01

    Thick SiC coatings of ˜100 μm on graphite tiles, prepared by chemical vapor infiltration of Si into the tiles and the following reactions between Si and C, are used as plasma facing material (PFM) on HT-7 superconducting tokamak and Experimental Advanced Superconducting Tokamak (EAST). With increase in the heating and driving power in EAST, the present plasma facing component (PFC) of the SiC/C tiles bolted to heat sink will be replaced by W coatings on actively cooled Cu heat sink, prepared by vacuum plasma spraying (VPS) adopting different interlayer. The VPS-W/Cu PFC with built-in cooling channels were prepared and mounted into the HT-7 acting as a movable limiter. Behavior of heat load onto the limiter and the material was studied. The Cu coatings on the Inconel 625 tubes were successfully prepared by high velocity air-fuel (HVAF) thermal spraying, being used as the liquid nitrogen (LN2) shields of the in-vessel cryopump for divertor pumping in EAST.

  9. Determination of boron in materials by cold neutron prompt gamma-ray activation analysis.

    PubMed

    Paul, Rick L

    2005-01-01

    An instrument for cold neutron prompt gamma-ray activation analysis (PGAA), located at the NIST Center for Neutron Research (NCNR), has proven useful for the measurement of boron in a variety of materials. Neutrons, moderated by passage through liquid hydrogen at 20 K, pass through a (58)Ni coated guide to the PGAA station in the cold neutron guide hall of the NCNR. The thermal equivalent neutron fluence rate at the sample position is 9 x 10(8) cm(-2) s(-1). Prompt gamma rays are measured by a cadmium- and lead-shielded high-purity germanium detector. The instrument has been used to measure boron mass fractions in minerals, in NIST SRM 2175 (Refractory Alloy MP-35-N) for certification of boron, and most recently in semiconductor-grade silicon. The limit of detection for boron in many materials is <10 ng g(-1). PMID:15614360

  10. Pyramidal Fin Arrays Performance Using Streamwise Anisotropic Materials by Cold Spray Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Cormier, Yannick; Dupuis, Philippe; Jodoin, Bertrand; Corbeil, Antoine

    2016-01-01

    This work evaluates the thermal and hydrodynamic performance of pyramidal fin arrays produced using cold spray as an additive manufacturing process. Near-net-shaped pyramidal fin arrays of pure aluminum, pure nickel, and stainless steel 304 were manufactured. Fin array characterization such as fin porosity level and surface roughness evaluation was performed. The thermal conductivities of the three different coating materials were measured by laser flash analysis. The results obtained show a lower thermal efficiency for stainless steel 304, whereas the performances of the aluminum and nickel fin arrays are similar. This result is explained by looking closely at the fin and substrate roughness induced by the cold gas dynamic additive manufacturing process. The multi-material fin array sample has a better thermal efficiency than stainless steel 304. The work demonstrates the potential of the process to produce streamwise anisotropic fin arrays as well as the benefits of such arrays.

  11. Cold spray deposition of Ti2AlC coatings for improved nuclear fuel cladding

    NASA Astrophysics Data System (ADS)

    Maier, Benjamin R.; Garcia-Diaz, Brenda L.; Hauch, Benjamin; Olson, Luke C.; Sindelar, Robert L.; Sridharan, Kumar

    2015-11-01

    Coatings of Ti2AlC MAX phase compound have been successfully deposited on Zircaloy-4 (Zry-4) test flats, with the goal of enhancing the accident tolerance of LWR fuel cladding. Low temperature powder spray process, also known as cold spray, has been used to deposit coatings ∼90 μm in thickness using powder particles of <20 μm. X-ray diffraction analysis showed the phase-content of the deposited coatings to be identical to the powders indicating that no phase transformation or oxidation had occurred during the coating deposition process. The coating exhibited a high hardness of about 800 HK and pin-on-disk wear tests using abrasive ruby ball counter-surface showed the wear resistance of the coating to be significantly superior to the Zry-4 substrate. Scratch tests revealed the coatings to be well-adhered to the Zry-4 substrate. Such mechanical integrity is required for claddings from the standpoint of fretting wear resistance and resisting wear handling and insertion. Air oxidation tests at 700 °C and simulated LOCA tests at 1005 °C in steam environment showed the coatings to be significantly more oxidation resistant compared to Zry-4 suggesting that such coatings can potentially provide accident tolerance to nuclear fuel cladding.

  12. Cold spray deposition of Ti2AlC coatings for improved nuclear fuel cladding

    NASA Astrophysics Data System (ADS)

    Maier, Benjamin R.; Garcia-Diaz, Brenda L.; Hauch, Benjamin; Olson, Luke C.; Sindelar, Robert L.; Sridharan, Kumar

    2015-11-01

    Coatings of Ti2AlC MAX phase compound have been successfully deposited on Zircaloy-4 (Zry-4) test flats, with the goal of enhancing the accident tolerance of LWR fuel cladding. Low temperature powder spray process, also known as cold spray, has been used to deposit coatings ˜90 μm in thickness using powder particles of <20 μm. X-ray diffraction analysis showed the phase-content of the deposited coatings to be identical to the powders indicating that no phase transformation or oxidation had occurred during the coating deposition process. The coating exhibited a high hardness of about 800 HK and pin-on-disk wear tests using abrasive ruby ball counter-surface showed the wear resistance of the coating to be significantly superior to the Zry-4 substrate. Scratch tests revealed the coatings to be well-adhered to the Zry-4 substrate. Such mechanical integrity is required for claddings from the standpoint of fretting wear resistance and resisting wear handling and insertion. Air oxidation tests at 700 °C and simulated LOCA tests at 1005 °C in steam environment showed the coatings to be significantly more oxidation resistant compared to Zry-4 suggesting that such coatings can potentially provide accident tolerance to nuclear fuel cladding.

  13. Coatings for high-temperature structural materials: Trends and opportunities

    SciTech Connect

    1996-12-31

    This book assesses the state of the art of coatings materials and processes for gas-turbine blades and vanes, determines potential applications of coatings in high-temperature environments, identifies needs for improved coatings in terms of performance enhancements, design considerations, and fabrication processes, assesses durability of advanced coating systems in expected service environments, and discusses the required inspection, repair, and maintenance methods. The promising areas for research and development of materials and processes for improved coating systems and the approaches to increased coating standardization are identified, with an emphasis on materials and processes with the potential for improved performance, quality, reproducibility, or manufacturing cost reduction.

  14. Microstructure Characteristics and Mechanical Properties of Al-12Si Coatings on AZ31 Magnesium Alloy Produced by Cold Spray Technique

    NASA Astrophysics Data System (ADS)

    Hao, Yi; Wang, Ji-qiang; Cui, Xin-yu; Wu, Jie; Li, Tie-fan; Xiong, Tian-ying

    2016-06-01

    The cold spray technique was to deposit Al-12Si coatings on AZ31 magnesium alloy. The influence of gas pressure and gas temperature on the microstructure of coatings was investigated so as to optimize the process parameters. OM, SEM, and XRD were used to characterize the as-sprayed coatings. Mechanical properties including Vickers microhardness and adhesion strength were measured in order to evaluate coating quality. Test results indicate that the Al-12Si coatings possess the same crystal structure with powders, sufficient thickness, low porosity, high hardness, and excellent adhesion strength under optimal cold spray process parameters.

  15. Microstructure Characteristics and Mechanical Properties of Al-12Si Coatings on AZ31 Magnesium Alloy Produced by Cold Spray Technique

    NASA Astrophysics Data System (ADS)

    Hao, Yi; Wang, Ji-qiang; Cui, Xin-yu; Wu, Jie; Li, Tie-fan; Xiong, Tian-ying

    2016-04-01

    The cold spray technique was to deposit Al-12Si coatings on AZ31 magnesium alloy. The influence of gas pressure and gas temperature on the microstructure of coatings was investigated so as to optimize the process parameters. OM, SEM, and XRD were used to characterize the as-sprayed coatings. Mechanical properties including Vickers microhardness and adhesion strength were measured in order to evaluate coating quality. Test results indicate that the Al-12Si coatings possess the same crystal structure with powders, sufficient thickness, low porosity, high hardness, and excellent adhesion strength under optimal cold spray process parameters.

  16. Ultrasonic cold forming of aircraft sheet materials

    NASA Astrophysics Data System (ADS)

    Devine, J.; Krause, P. C.

    1981-01-01

    Ultrasonic forming was investigated as a means for shaping aircraft sheet materials, including titanium 6Al-4V alloy, nickel, and stainless steel AM355-CRT, into a helicopter rotor blade nosecap contour. Equipment for static forming of small coupons consisted of a modified 4000 watt ultrasonic spot welder provided with specially designed punch and die sets. The titanium alloy was successfully formed to a 60 degree angle in one step with ultrasonics, but invariably cracked under static force alone. Nickel had a low enough yield strength that it could be successfully formed either with or without ultrasonics. Insufficient ultrasonic power was available to produce beneficial effect with the high-strength steel. From analogy with commercially used ultrasonic tube drawing, it was postulated that dynamic forming of long lengths of the nosecap geometry could be achieved with an ultrasonic system mounted on a draw bench. It was recommended that the ultrasonic technique be considered for forming other aircraft sheet geometries, particularly involving titanium alloy.

  17. Tribological evaluation and analysis of coating materials

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1992-01-01

    A physical characterization of coating materials by analytical techniques such as XPS, AES, ellipsometry, and nuclear reaction analysis can contribute to the understanding of adhesion and friction of the coatings and can partially predict the tribological properties of the coatings. This two-part paper describes the tribological properties and physical characteristics of (1) diamondlike carbon (DLC) films and (2) silicon nitride (SiN(x)) films. Emphasis is to relate plasma deposition conditions to the film chemistry and composition and to the adhesion and friction of the films. With the DLC films, the higher the plasma deposition power, the less the hydrogen concentration and the greater the film density and the hardness. The friction behavior of DLC films deposited at higher deposition powers (200 to 300 W) is similar to that of bulk diamond. Even in a vacuum, the DLC films effectively lubricate ceramic surfaces (Si3N4) at temperatures to 500 C. With SiN(x) films, the silicon to nitrogen ratios and the amount of amorphous silicon depend on deposition frequency. The presence of rich amorphous silicon in the high-frequency plasma-deposited SiN(x) films increases their adhesion and friction above 500 C in vacuum.

  18. Advanced Materials and Coatings for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2004-01-01

    In the application area of aerospace tribology, researchers and developers must guarantee the highest degree of reliability for materials, components, and systems. Even a small tribological failure can lead to catastrophic results. The absence of the required knowledge of tribology, as Professor H.P. Jost has said, can act as a severe brake in aerospace vehicle systems-and indeed has already done so. Materials and coatings must be able to withstand the aerospace environments that they encounter, such as vacuum terrestrial, ascent, and descent environments; be resistant to the degrading effects of air, water vapor, sand, foreign substances, and radiation during a lengthy service; be able to withstand the loads, stresses, and temperatures encountered form acceleration and vibration during operation; and be able to support reliable tribological operations in harsh environments throughout the mission of the vehicle. This presentation id divided into two sections: surface properties and technology practice related to aerospace tribology. The first section is concerned with the fundamental properties of the surfaces of solid-film lubricants and related materials and coatings, including carbon nanotubes. The second is devoted to applications. Case studies are used to review some aspects of real problems related to aerospace systems to help engineers and scientists to understand the tribological issues and failures. The nature of each problem is analyzed, and the tribological properties are examined. All the fundamental studies and case studies were conducted at the NASA Glenn Research Center.

  19. ETV Program Report: Coatings for Wastewater Collection Systems - Standard Cement Materials, Epoxy Coating 4553

    EPA Science Inventory

    The Standard Cement Materials, Inc. Standard Epoxy Coating 4553™ (SEC 4553) epoxy coating used for wastewater collection system rehabilitation was evaluated by EPA’s Environmental Technology Verification Program under laboratory conditions at the Center for Innovative Grouting Ma...

  20. Mechanical and Tribological Properties of Cold-Sprayed Ti Coatings on Ti-6Al-4V Substrates

    NASA Astrophysics Data System (ADS)

    Khun, N. W.; Tan, A. W. Y.; Liu, E.

    2016-04-01

    A cold spray process was used to deposit titanium (Ti) coatings of different thicknesses on commercial Ti-6Al-4V (Ti64) substrates. The hardness of the Ti coatings was measured using a Vickers micro-indenter. It was found that the thicker Ti coatings had higher hardness probably due to the better uniformity and higher density of the coatings. The tribological results showed that the friction and wear of the Ti coatings tested against a steel ball under dry condition became lower with higher thickness probably due to the higher wear resistance of the thicker coatings associated with their higher hardness. The specific wear rates of all the Ti coatings were significantly lower than that of the Ti64 substrate as a result of the higher wear resistance of the Ti coatings associated with their cold-worked microstructures and the formation of high wear resistant oxide layers on their wear tracks during the wear testing.

  1. Effect of gas flow swirling on coating deposition by the cold gas-dynamic spray method

    NASA Astrophysics Data System (ADS)

    Kiselev, S. P.; Kiselev, V. P.; Zaikovskii, V. N.

    2012-03-01

    The effect of gas flow swirling on the process of coating deposition onto a target by the cold gas-dynamic spray method is studied experimentally and numerically. Flow swirling is found to change the gas flow field and to reduce the gas flow rate under typical conditions of cold gas-dynamic spray. In a non-swirled flow, the shape of the deposited spot is similar to a sharp cone. In contrast, the deposited spot in a swirled flow is shaped as a crater without particles at the center of this crater. It is found that this effect is caused by centrifugal forces acting on particles in a swirled gas flow.

  2. The effects of Aloe vera (Aloe barbadensis) coating on the quality of shrimp during cold storage.

    PubMed

    Soltanizadeh, Nafiseh; Mousavinejad, Mohsen S

    2015-10-01

    Green tiger shrimp (Penaeus semisulcatus) is an important aquaculture species worldwide. Its perishable nature, however, needs preservation methods to ensure its quality and shelf life. In this study, the effects of Aloe vera coating on the quality and shelf life of shrimps during cold storage were investigated. Shrimp samples were dipped in aqueous solutions containing 25%, 50%, 75%, and 100% Aloe vera gel before storage at 4 °C for 7 days. Drip loss, pH, TBA, TVB-N, and texture of both the control and treated shrimp samples were analyzed periodically. There were significant differences between coated shrimps and the control group in all parameters evaluated. Aloe vera at 75% and 100% concentrations was able to prevent lipid oxidation and drip loss properly; however, coatings containing 25% Aloe vera did not have the desired effects on these characteristics. Shrimps coated with higher concentrations of Aloe vera had better textural properties during cold storage. Results also indicated the positive effects of Aloe vera coating on the sensory quality of shrimp. PMID:26396412

  3. Selective Laser Treatment on Cold-Sprayed Titanium Coatings: Numerical Modeling and Experimental Analysis

    NASA Astrophysics Data System (ADS)

    Carlone, Pierpaolo; Astarita, Antonello; Rubino, Felice; Pasquino, Nicola; Aprea, Paolo

    2016-03-01

    In this paper, a selective laser post-deposition on pure grade II titanium coatings, cold-sprayed on AA2024-T3 sheets, was experimentally and numerically investigated. Morphological features, microstructure, and chemical composition of the treated zone were assessed by means of optical microscopy, scanning electron microscopy, and energy dispersive X-ray spectrometry. Microhardness measurements were also carried out to evaluate the mechanical properties of the coating. A numerical model of the laser treatment was implemented and solved to simulate the process and discuss the experimental outcomes. Obtained results highlighted the key role played by heat input and dimensional features on the effectiveness of the treatment.

  4. Resistance of dentin coating materials against abrasion by toothbrush.

    PubMed

    Gando, Iori; Ariyoshi, Meu; Ikeda, Masaomi; Sadr, Alireza; Nikaido, Toru; Tagami, Junji

    2013-01-01

    Thin-film coating of root dentin surface by all-in-one adhesives has been shown to be an effective option to prevent root surface caries. The purpose of this study was to investigate the wear resistance against toothbrush abrasion of two all-in-one coating materials; Shield Force (SF) and Hybrid Coat (HC). Bovine dentin surfaces were covered with one of the coating materials; SF or HC. After storage in water for 24 h, the testing surface was subjected to the toothbrush abrasion test up to 50,000 cycles either in water or toothpaste slurry. The remaining thickness of the coating material was measured using SEM. Toothpaste slurry significantly increased rate of tooth brush abrasion of the coating materials. While SF and HC wore at a similar pace under toothbrush abrasion, SF had a thicker coat and could protect dentin longer, up to 50,000 cycles. PMID:23370872

  5. Boron nitride coatings and materials for use in aggressive environments

    SciTech Connect

    Besmann, T.M.; Lee, W.Y.; Young, J.P.; Xiao, H.

    1997-12-31

    Boron nitride coatings and structures have demonstrated significant resistance to many corrosive environments. These coatings may have application in the protection of sensors needed for measuring a variety of properties such as temperature and chemistry. In addition, boron nitride materials may offer advantages as structural materials in high temperature materials processing. In this study, BN is assessed for use in aluminum smelting.

  6. High-Current Cold Cathode Employing Diamond and Related Materials

    SciTech Connect

    Hirshfield, Jay L.

    2014-10-22

    The essence of this project was for diamond films to be deposited on cold cathodes to improve their emission properties. Films with varying morphology, composition, and size of the crystals were deposited and the emission properties of the cathodes that utilize such films were studied. The prototype cathodes fabricated by the methods developed during Phase I were tested and evaluated in an actual high-power RF device during Phase II. These high-power tests used the novel active RF pulse compression system and the X-band magnicon test facility at US Naval Research Laboratory. In earlier tests, plasma switches were employed, while tests under this project utilized electron-beam switching. The intense electron beams required in the switches were supplied from cold cathodes embodying diamond films with varying morphology, including uncoated molybdenum cathodes in the preliminary tests. Tests with uncoated molybdenum cathodes produced compressed X-band RF pulses with a peak power of 91 MW, and a maximum power gain of 16.5:1. Tests were also carried out with switches employing diamond coated cathodes. The pulse compressor was based on use of switches employing electron beam triggering to effect mode conversion. In experimental tests, the compressor produced 165 MW in a ~ 20 ns pulse at ~18× power gain and ~ 140 MW at ~ 16× power gain in a 16 ns pulse with a ~ 7 ns flat-top. In these tests, molybdenum blade cathodes with thin diamond coatings demonstrated good reproducible emission uniformity with a 100 kV, 100 ns high voltage pulse. The new compressor does not have the limitations of earlier types of active pulse compressors and can operate at significantly higher electric fields without breakdown.

  7. Characterization of commercially cold sprayed copper coatings and determination of the effects of impacting copper powder velocities

    NASA Astrophysics Data System (ADS)

    Jakupi, P.; Keech, P. G.; Barker, I.; Ramamurthy, S.; Jacklin, R. L.; Shoesmith, D. W.; Moser, D. E.

    2015-11-01

    Copper coated steel containers are being developed for the disposal of high level nuclear waste using processes such as cold spray and electrodeposition. Electron Back-Scatter Diffraction has been used to determine the microstructural properties and the quality of the steel-copper coating interface. The influence of the nature of the cold-spray carrier gas as well as its temperature and pressure (velocity) on the coating's plastic strain and recrystallization behaviour have been investigated, and one commercially-produced electrodeposited coating characterized. The quality of the coatings was assessed using the coincident site lattice model to analyse the properties of the grain boundaries. For cold spray coatings the grain size and number of coincident site lattice grain boundaries increased, and plastic strain decreased, with carrier gas velocity. In all cases annealing improved the quality of the coatings by increasing texture and coincidence site-lattices, but also increased the number of physical voids, especially when a low temperature cold spray carrier gas was used. Comparatively, the average grain size and number of coincident site-lattices was considerably larger for the strongly textured electrodeposited coating. Tensile testing showed the electrodeposited coating was much more strongly adherent to the steel substrate.

  8. Influence of the Substrate on the Formation of Metallic Glass Coatings by Cold Gas Spraying

    NASA Astrophysics Data System (ADS)

    Henao, John; Concustell, Amadeu; Dosta, Sergi; Cinca, Núria; Cano, Irene G.; Guilemany, Josep M.

    2016-06-01

    Cold gas spray technology has been used to build up coatings of Fe-base metallic glass onto different metallic substrates. In this work, the effect of the substrate properties on the viscoplastic response of metallic glass particles during their impact has been studied. Thick coatings with high deposition efficiencies have been built-up in conditions of homogeneous flow on substrates such as Mild Steel AISI 1040, Stainless Steel 316L, Inconel 625, Aluminum 7075-T6, and Copper (99.9%). Properties of the substrate have been identified to play an important role in the viscoplastic response of the metallic glass particles at impact. Depending on the process gas conditions, the impact morphologies show not only inhomogeneous deformation but also homogeneous plastic flow despite the high strain rates, 108 to 109 s-1, involved in the technique. Interestingly, homogenous deformation of metallic glass particles is promoted depending on the hardness and the thermal diffusivity of the substrate and it is not exclusively a function of the kinetic energy and the temperature of the particle at impact. Coating formation is discussed in terms of fundamentals of dynamics of undercooled liquids, viscoplastic flow mechanisms of metallic glasses, and substrate properties. The findings presented in this work have been used to build up a detailed scheme of the deposition mechanism of metallic glass coatings by the cold gas spraying technology.

  9. Materials characteristics of uncoated/ceramic-coated implant materials.

    PubMed

    Lacefield, W R

    1999-06-01

    In this paper, the biocompatibility of dental implant materials is discussed in the context of both the mechanical characteristics of the materials and the type of surface presented to the surrounding tissues. The proper functioning of the implant depends on whether it possesses the strength necessary to withstand loading within the expected range, with other properties such as elongation being of importance in some instances. A suitable modulus of elasticity may be of major importance in situations when optimum load transmission from the implant into the surrounding bone is key to the successful functioning of the device. Dental implants present a wide range of surfaces to the surrounding tissues based on surface composition, texture, charge energy, and cleanliness (sterility). Metallic implants are characterized by protective oxide layers, but ion release is still common with these materials, and is a function of passivation state, composition, and corrosion potential. An effective surface treatment for titanium appears to be passivation or anodization in a suitable solution prior to implantation. Inert ceramic surfaces exhibit minimal ion release, but are similar to metals in that they do not form a high energy bond to the surrounding bone. Some of the newly developed dental implant alloys such as titanium alloys, which contain zirconium and niobium, and high-strength ceramics such as zirconia may offer some advantages (such as lower modulus of elasticity) over the conventional materials. Calcium phosphate ceramic coatings are commonly used to convert metallic surfaces into a more bioactive state and typically cause faster bone apposition. There is a wide range of ceramic coatings containing calcium and phosphorus, with the primary difference in many of these materials being in the rate of ion release. Although their long-term success rate is unknown, the calcium phosphate surfaces seem to have a higher potential for attachment of osteoinductive agents than do

  10. Microstructure, Mechanical Properties, and Two-Body Abrasive Wear Behavior of Cold-Sprayed 20 vol.% Cubic BN-NiCrAl Nanocomposite Coating

    NASA Astrophysics Data System (ADS)

    Luo, Xiao-Tao; Yang, Er-Juan; Shang, Fu-Lin; Yang, Guan-Jun; Li, Chen-Xin; Li, Chang-Jiu

    2014-10-01

    20 vol.% cubic boron nitride (cBN) dispersoid reinforced NiCrAl matrix nanocomposite coating was prepared by cold spray using mechanically alloyed nanostructured composite powders. The as-sprayed nanocomposite coating was annealed at a temperature of 750 °C to enhance the inter-particle bonding. Microstructure of spray powders and coatings was characterized. Vickers microhardness of the coatings was measured. Two-body abrasive wear behavior of the coatings was examined on a pin-on-disk test. It was found that, in mechanically alloyed composite powders, nano-sized and submicro-sized cBN particles are uniformly distributed in nanocrystalline NiCrAl matrix. Dense coating was deposited by cold spray at a gas temperature of 650 °C with the same phases and grain size as those of the starting powder. Vickers hardness test yielded a hardness of 1063 HV for the as-sprayed 20 vol.% cBN-NiCrAl coating. After annealed at 750 °C for 5 h, unbonded inter-particle boundaries were partially healed and evident grain growth of nanocrystalline NiCrAl was avoided. Wear resistance of the as-sprayed 20 vol.% cBN-NiCrAl nanocomposite coating was comparable to the HVOF-sprayed WC-12Co coating. Annealing of the nanocomposite coating resulted in the improvement of wear resistance by a factor of ~33% owing to the enhanced inter-particle bonding. Main material removal mechanisms during the abrasive wear are also discussed.

  11. Formation of Expanded Austenite on a Cold-Sprayed AISI 316L Coating by Low-Temperature Plasma Nitriding

    NASA Astrophysics Data System (ADS)

    Adachi, Shinichiro; Ueda, Nobuhiro

    2015-12-01

    Low-temperature plasma nitriding at temperatures below 450 °C is commonly applied to austenitic stainless steels to enhance wear resistance, while maintaining corrosion resistance, by forming expanded austenite (known as the S-phase). In this work, low-temperature plasma nitriding of cold-sprayed AISI 316L coatings was examined. A cold-spray technique was developed to produce metal coatings with less oxidation. However, the cold-sprayed AISI 316L coating obtained by use of nitrogen gas as propellant contained many interconnected pores and cracks, and was, consequently, unsuitable as an anticorrosive coating. Therefore, laser post-treatment was used to modify the coating and increase its density to similar to that of bulk steel. The anticorrosive performance of this coating on a carbon steel substrate in NaCl solution was substantially improved. Subsequent low-temperature plasma nitriding enhanced the wear resistance by two orders of magnitude. It is concluded that cold-sprayed AISI 316L coatings treated by laser post-treatment and subsequent low-temperature plasma nitriding could be used as protective coatings under severe wear and corrosion conditions.

  12. Novel hybrid polymeric materials for barrier coatings

    NASA Astrophysics Data System (ADS)

    Pavlacky, Erin Christine

    Polymer-clay nanocomposites, described as the inclusion of nanometer-sized layered silicates into polymeric materials, have been widely researched due to significant enhancements in material properties with the incorporation of small levels of filler (1--5 wt.%) compared to conventional micro- and macro-composites (20--30 wt.%). One of the most promising applications for polymer-clay nanocomposites is in the field of barrier coatings. The development of UV-curable polymer-clay nanocomposite barrier coatings was explored by employing a novel in situ preparation technique. Unsaturated polyesters were synthesized in the presence of organomodified clays by in situ intercalative polymerization to create highly dispersed clays in a precursor resin. The resulting clay-containing polyesters were crosslinked via UV-irradiation using donor-acceptor chemistry to create polymer-clay nanocomposites which exhibited significantly enhanced barrier properties compared to alternative clay dispersion techniques. The impact of the quaternary alkylammonium organic modifiers, used to increase compatibility between the inorganic clay and organic polymer, was studied to explore influence of the organic modifier structure on the nanocomposite material properties. By incorporating just the organic modifiers, no layered silicates, into the polyester resins, reductions in film mechanical and thermal properties were observed, a strong indicator of film plasticization. An alternative in situ preparation method was explored to further increase the dispersion of organomodified clay within the precursor polyester resins. In stark contrast to traditional in situ polymerization methods, a novel "reverse" in situ preparation method was developed, where unmodified montmorillonite clay was added during polyesterification to a reaction mixture containing the alkylammonium organic modifier. The resulting nanocomposite films exhibited reduced water vapor permeability and increased mechanical properties

  13. Handbook of Tribology: Materials, coatings, and surface treatments

    SciTech Connect

    Bhushan, B.; Gupta, B.K.

    1991-12-31

    This book provides an introduction to tribological principles as well as all types of coatings, surface treatments and modifications. The first chapter provides an overview of the various types of lubricants. Chapter two provides a review of friction, wear, and lubrication. Chapter three covers physics of tribological materials including the nature, shape, and properties of surfaces; surface interactions with the environment; phase equilibria; and microstructural effects on friction and wear. Chapter four covers metals and ceramics and chapter five covers solid lubricants and self-lubricating solids. Chapter six provides an overview of coating deposition and surface treatment techniques, including hard facing, vapor deposition, a variety of miscellaneous coating techniques, and surface treatment techniques including microstructural modification, diffusion treatments, and implantation techniques. This chapter also provides a section giving criteria for selecting coating material, deposition and surface treatment techniques. Chapter seven deals with surface preparation for coating deposition. Cleaning methods using solvents, emulsions, alkalines, acids, pickling, salt bath descaling, ultrasonics, and plasmas are described. Surface roughening techniques that are described include abrasive blasting, barrel finishing, mechanical polishing and buffing, chemical etching, and electro-polishing. The chapter concludes with a discussion of techniques for monitoring surface cleanliness and texture. Chapters 8-15 are devoted to much more detailed discussion of the following topics: coating deposition by hard facing; coating deposition from vapor phase; coating deposition by miscellaneous techniques; surface treatments by thermal and chemical processes; surface treatments by ion beams; soft coatings; hard coatings; and screening methodology for materials coatings and surface treatments.

  14. Comparison of Oxidation and Microstructure of Warm-Sprayed and Cold-Sprayed Titanium Coatings

    NASA Astrophysics Data System (ADS)

    Kim, KeeHyun; Kuroda, Seiji; Watanabe, Makoto; Huang, RenZhong; Fukanuma, Hirotaka; Katanoda, Hiroshi

    2012-06-01

    Thick titanium coatings were prepared by the warm spraying (WS) and cold spraying (CS) processes to investigate the oxidation and microstructure of the coating layers. Prior to the coating formations, the temperature and velocity of in-flight titanium powder particles were numerically calculated. Significant oxidation occurred in the WS process using higher gas temperature conditions with low nitrogen flow rate, which is mixed to the flame jet of a high velocity oxy-fuel (HVOF) spray gun in order to control the temperature of the propellant gas. Oxidation, however, decreased strikingly as the nitrogen flow rate increased. In the CS process using nitrogen or helium as a propellant gas, little oxidation was observed. Even when scanning electron microscopy or an x-ray diffraction method did not detect oxides in the coating layers produced by WS using a high nitrogen flow rate or by CS using helium, the inert gas fusion method revealed minor increases of oxygen content from 0.01 to 0.2 wt.%. Most of the cross-sections of the coating layers prepared by conventional mechanical polishing looked dense. However, the cross-sections prepared by an ion-milling method revealed the actual microstructures containing small pores and unbounded interfaces between deposited particles.

  15. Characterization of Cold Sprayed CuCrAl Coated GRCop-84 Substrates for Reusable Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Raj, S . V.; Barrett, C. A.; Lerch, B. A.; Karthikeyan, J.; Ghosn, L. J.; Haynes, J.

    2005-01-01

    An advanced Cu-8(at.%)Cr-4%Nb alloy developed at NASA's Glenn Research Center, and designated as GRCop-84, is currently being considered for use as combustor liners and nozzles in NASA's future generations of reusable launch vehicles (RLVs). Despite the fact that this alloy has superior mechanical and oxidation properties compared to many commercially available copper alloys, it is felt that its high temperature and environmental resistance capabilities can be further enhanced with the development and use of suitable coatings. Several coatings and processes are currently being evaluated for their suitability and future down selection. A newly developed CuCrAl has shown excellent oxidation resistance compared to current generation Cu-Cr coating alloys. Cold spray technology for depositing the CuCrAl coating on a GRCop-84 substrate is currently being developed under NASA's Next Generation Launch Technology (NGLT) Propulsion Research and Technology (PR&T) project. The microstructures, mechanical and thermophysical properties of overlay coated GRCop-84 substrates are discussed.

  16. Understanding the effects of process parameters on the properties of cold gas dynamic sprayed pure titanium coatings

    NASA Astrophysics Data System (ADS)

    Wong, Wilson

    The cold gas dynamic spraying of commercially pure titanium coatings was investigated. Specifically, the relationship between several key cold spray parameters on the quality of the resulting coatings was studied in order to gain a more thorough understanding of the cold spray process. To achieve this goal, three distinct investigations were performed. The first part of the investigation focussed on the effect of propelling gas, particularly helium and nitrogen, during the cold spraying of titanium coatings. Coatings were characterised by SEM and were evaluated for their deposition efficiency (DE), microhardness, and porosity. In selected conditions, three particle velocities were investigated such that for each condition, the propelling gasses temperature and pressure were attuned to attain similar particle velocities for each gas. In addition, a thick and fully dense cold sprayed titanium coating was achieved with optimised spray parameters and nozzle using helium. The corresponding average particle velocity was 1173 m/s. The second part of the investigation studied the effect of particle morphology (spherical, sponge, and irregular) and size distributions (mean particle sizes of 20, 29, and 36 mum) of commercially pure titanium on the mechanical properties of the resulting cold sprayed coatings. Numerous powder and coating characterisations were performed. From these data, semi-empirical flow (stress-strain) curves were generated based on the Johnson-Cook plasticity model which could be used as a measure of cold sprayability. Cold sprayability can be defined as the ease with which a powder can be cold sprayed. It was found that the sponge and irregular commercially pure titanium powders had higher oxygen content, poorer powder flowability, higher compression ratio, lower powder packing factor, and higher average particle impact velocities compared to the spherical powders. XRD results showed no new phases present when comparing the various feedstock powders to

  17. Advanced Porous Coating for Low-Density Ceramic Insulation Materials

    NASA Technical Reports Server (NTRS)

    Leiser, Daniel B.; Churchward, Rex; Katvala, Victor; Stewart, David; Balter, Aliza

    1988-01-01

    The need for improved coatings on low-density reusable surface insulation (RSI) materials used on the space shuttle has stimulated research into developing tougher coatings. The processing of a new porous composite "coating" for RST called toughened unipiece fibrous insulation Is discussed. Characteristics including performance in a simulated high-speed atmospheric entry, morphological structure before and after this exposure, resistance to Impact, and thermal response to a typical heat pulse are described. It is shown that this coating has improved impact resistance while maintaining optical and thermal properties comparable to the previously available reaction-cured glass coating.

  18. Supersonic Particle Impacts: Cold Spray Deposition of Polymeric Material

    NASA Astrophysics Data System (ADS)

    Bush, Trenton; Schmidt, David; Rothstein, Jonathan P.

    2015-11-01

    When a solid, ductile particle impacts a substrate at sufficient velocity, the resulting heat, pressure, and plastic deformation at the interface can produce bonding. The use of a supersonic gas flow to accelerate such particles is known as Cold Spray deposition. The Cold Spray process has been commercialized for some metallic materials, but further research is required to unlock the exciting material properties possible with polymeric compounds. In this work, we present a combined computational and experimental study whose aim is to define the necessary flow conditions for a convergent-divergent de Laval nozzle to produce successful bonding in a range of polymers. From our initial exploration of temperature-pressure space, we will reveal a material dependent `window of deposition' where successful deposition is possible. Furthermore, we will present our computational work on the development of an optimized nozzle profile that maximizes particle total energy (kinetic plus thermal) upon impact and thus maximizes the likelihood of successful deposition. These predictions will be confirmed by the experimental results presented.

  19. 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)

  20. Frost resistance of concrete surfaces coated with waterproofing materials

    NASA Astrophysics Data System (ADS)

    Klovas, A.; Dauksys, M.; Ciuprovaite, G.

    2015-03-01

    Present research lays emphasis on the problem of concrete surface exposed to aggressive surrounding quality. The test was conducted with concrete surfaces coated with different waterproofing materials exposed in solution of 3 % of sodium sulphate. Research was performed according to LST EN 1338:2003 standard requirements. Technological properties of concrete mixture as well as physical-mechanical properties of formed concrete specimens were established. The resistance of concrete to freezing - thawing cycles was prognosticated according to the porosity parameters established by the kinetic of water absorption. Five different waterproofing materials (coatings) such as liquid bitumen-rubber based, elastic fiber-strengthened, silane-siloxane based emulsion, mineral binder based and liquid rubber (caoutchouc) based coatings were used. Losses by mass of coating materials and specimens surface fractures were calculated based on the results of frost resistance test. Open code program "ImageJ" was used for visual analysis of concrete specimens. Based on the results, aggressive surrounding did not influence specimens coated with elastic, fibre-strengthened, mineral materials. On the other hand, specimens coated with liquid rubber (caoutchouc) based material were greatly influenced by aggressive surrounding. The biggest losses of specimen surface concrete (fractures) were obtained with silane-siloxane based emulsion coating. Generally, specimens coated with waterproofing materials were less influenced by aggressive surrounding compared with those without.

  1. Bioactive alginate coatings to control Listeria monocytogenes on cold-smoked salmon slices and fillets.

    PubMed

    Neetoo, Hudaa; Ye, Mu; Chen, Haiqiang

    2010-01-01

    The relatively high incidence of Listeria monocytogenes in cold smoked salmon (CSS) is of concern as CSS is a ready-to-eat product. No post-processing measures are currently available to control this pathogen in CSS. The objective of this study was to develop an effective antimicrobial edible coating containing organic salts to control the growth of L. monocytogenes in CSS slices and fillets. An in-house made formulation consisting of sodium lactate (SL, 0-2.4%) and sodium diacetate (SD, 0-0.25%) as well as 2.5% OptiForm (a commercial formulation of SL and SD) were incorporated into five edible coatings: alginate, kappa-carrageenan, pectin, gelatin or starch. The coatings were applied onto the surface of CSS slices inoculated with L. monocytogenes to an inoculum level of 500 CFU/cm(2) ( approximately 3 log CFU/g) and stored at room temperature (22 degrees C) for 6 days. Alginate coating was found to be the most effective carrier for the various antimicrobial treatments in inhibiting the growth of L. monocytogenes. In the second phase of the study, CSS slices and fillets inoculated with the pathogen at a level of 500 CFU/cm(2) were coated with alginate incorporating the in-house made and the commercial (OptiForm) SL/SD based formulations and stored for 30 days at 4 degrees C. When cold-smoked salmon slices and fillets were stored at 4 degrees C, alginate coatings supplemented with 2.4%SL/0.25%SD and the commercial product OptiForm significantly delayed the growth of L. monocytogenes during the 30-day storage with final counts reaching 4.1 and 3.3 log CFU/g (slices) and 4.4 and 3.8 log CFU/g (fillets), respectively, while the counts in their untreated counterparts were significantly higher (P<0.05) reaching 7.3 and 6.8 log CFU/g for slices and fillets, respectively. Therefore, this study demonstrates the effectiveness of using an alginate-based coating containing lactate and diacetate to control the growth of L. monocytogenes to enhance the microbiological safety of

  2. Cold neutron diffraction contrast tomography of polycrystalline material.

    PubMed

    Peetermans, S; King, A; Ludwig, W; Reischig, P; Lehmann, E H

    2014-11-21

    Traditional neutron imaging is based on the attenuation of a neutron beam through scattering and absorption upon traversing a sample of interest. It offers insight into the sample's material distribution at high spatial resolution in a non-destructive way. In this work, it is expanded to include the diffracted neutrons that were ignored so far and obtain a crystallographic distribution (grain mapping). Samples are rotated in a cold neutron beam of limited wavelength band. Projections of the crystallites formed by the neutrons they diffract are captured on a two dimensional imaging detector. Their positions on the detector reveal their orientation whereas the projections themselves are used to reconstruct the shape of the grains. Indebted to established synchrotron diffraction contrast tomography, this 'cold neutron diffraction contrast tomography' is performed on recrystallized aluminium for experimental comparison between both. Differences between set-up and method are discussed, followed by the application range in terms of sample properties (crystallite size and number, mosaicity and typical materials). Neutron diffraction contrast tomography allows to study large grains in bulky metallic structures. PMID:25274183

  3. Influence of coating material on the flowability and dissolution of dry-coated fine ibuprofen powders.

    PubMed

    Qu, Li; Zhou, Qi Tony; Denman, John A; Stewart, Peter J; Hapgood, Karen P; Morton, David A V

    2015-10-12

    This study investigates the effects of a variety of coating materials on the flowability and dissolution of dry-coated cohesive ibuprofen powders, with the ultimate aim to use these in oral dosage forms. A mechanofusion approach was employed to apply a 1% (w/w) dry coating onto ibuprofen powder with coating materials including magnesium stearate (MgSt), L-leucine, sodium stearyl fumarate (SSF) and silica-R972. No significant difference in particle size or shape was measured following mechanofusion with any material. Powder flow behaviours characterised by the Freeman FT4 system indicated coatings of MgSt, L-leucine and silica-R972 produced a notable surface modification and substantially improved flow compared to the unprocessed and SSF-mechanofused powders. ToF-SIMS provided a qualitative measure of coating extent, and indicated a near-complete layer on the drug particle surface after dry coating with MgSt or silica-R972. Of particular note, the dissolution rates of all mechanofused powders were enhanced even with a coating of a highly hydrophobic material such as magnesium stearate. This surprising increase in dissolution rate of the mechanofused powders was attributed to the lower cohesion and the reduced agglomeration after mechanical coating. PMID:26215464

  4. Weightless Environment Training Facility (WETF) materials coating evaluation, volume 3

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This volume consists of Appendices C, D, E, and F to the report on the Weightless Environment Training Facility Materials Coating Evaluation project. The project selected 10 coating systems to be evaluated in six separate exposure environments, and subject to three tests for physical properties. Appendix C is the photographic appendix of the test panels. Appendix D details methods and procedures. Appendix E lists application equipment costs. Appendix F is a compilation of the solicitation of the candidate coating systems.

  5. Max Phase Materials And Coatings For High Temperature Heat Transfer Applications

    SciTech Connect

    Martinez-Rodriguez, M.; Garcia-Diaz, B.; Olson, L.; Fuentes, R.; Sindelar, R.

    2015-10-19

    Molten salts have been used as heat transfer fluids in a variety of applications within proposed Gen IV nuclear designs and in advanced power system such as Concentrating Solar Power (CSP). However, operating at elevated temperatures can cause corrosion in many materials. This work developed coating technologies for MAX phase materials on Haynes-230 and characterized the corrosion of the coatings in the presence of commercial MgCl2-KCl molten salt. Cold spraying of Ti2AlC and physical vapor deposition (PVD) of Ti2AlC or Zr2AlC were tested to determine the most effective form of coating MAX phases on structural substrates. Corrosion testing at 850°C for 100 hrs showed that 3.9 μm Ti2AlC by PVD was slightly protective while 117 μm Ti2AlC by cold spray and 3.6 μm Zr2AlC by PVD were completely protective. None of the tests showed decomposition of the coating (Ti or Zr) into the salt

  6. Preparation and characterization of energetic materials coated superfine aluminum particles

    NASA Astrophysics Data System (ADS)

    Liu, Songsong; Ye, Mingquan; Han, Aijun; Chen, Xin

    2014-01-01

    This work is devoted to protect the activity of aluminum in solid rocket propellants by means of solvent/non-solvent method in which nitrocellulose (NC) and Double-11 (shortened form of double-base gun propellant, model 11) have been used as coating materials. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the morphology of coated Al particles. Other characterization data of coated and uncoated Al particles, such as infrared absorption spectrum, laser particle size analysis and the active aluminum content were also studied. The thermal behavior of pure and coated aluminum samples have also been studied by simultaneous thermogravimetry-differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC). The results indicated that: superfine aluminum particles could be effectively coated with nitrocellulose and Double-11 through a solvent/non-solvent method. The energetic composite particles have core-shell structures and the thickness of the coating film is about 20-50 nm. The active aluminum content of different coated samples was measured by means of oxidation-reduction titration method. The results showed that after being stored in room temperature and under 50% humidity condition for about 4months the active aluminum content of coated Al particles decreased from 99.8 to 95.8% (NC coating) and 99.2% (Double-11 coating) respectively. Double-11 coating layer had a much better protective effect. The TG-DTA and DSC results showed that the energy amount and energy release rate of NC coated and Double-11 coated Al particles were larger than those of the raw Al particles. Double-11 coated Al particles have more significant catalytic effect on the thermal decomposition characters of AP than that of NC coated Al particles. These features accorded with the energy release characteristics of solid propellant.

  7. Superhydrophobic materials and coatings: a review

    NASA Astrophysics Data System (ADS)

    Simpson, John T.; Hunter, Scott R.; Aytug, Tolga

    2015-07-01

    Over the past few years, the scientific community, as well as the world’s coatings industry has seen the introduction of oxide/polymer-based superhydrophobic surfaces and coatings with exceptional water repellency. Online videos have caught the public’s imagination by showing people walking through mud puddles without getting their tennis shoes wet or muddy, and water literally flying off coated surfaces. This article attempts to explain the basics of this behavior and to discuss and explain the latest superhydrophobic technological breakthroughs. Since superhydrophobic surfaces and coatings can fundamentally change how water interacts with surfaces, and the fact that earth is a water world, it can legitimately be said that this technology has the potential to literally change the world.

  8. Coated conductors for power applications: materials challenges

    NASA Astrophysics Data System (ADS)

    Obradors, Xavier; Puig, Teresa

    2014-04-01

    This manuscript reports on the recent progress and the remaining materials challenges in the development of coated conductors (CCs) for power applications and magnets, with a particular emphasis on the different initiatives being active at present in Europe. We first summarize the scientific and technological scope where CCs have been raised as a complex technology product and then we show that there exists still much room for performance improvement. The objectives and CC architectures being explored in the scope of the European project EUROTAPES are widely described and their potential in generating novel breakthroughs emphasized. The overall goal of this project is to create synergy among academic and industrial partners to go well beyond the state of the art in several scientific issues related to CCs’ enhanced performances and to develop nanoengineered CCs with reduced costs, using high throughput manufacturing processes which incorporate quality control tools and so lead to higher yields. Three general application targets are considered which will require different conductor architectures and performances and so the strategy is to combine vacuum and chemical solution deposition approaches to achieve the targeted goals. A few examples of such approaches are described related to defining new conductor architectures and shapes, as well as vortex pinning enhancement through novel paths towards nanostructure generation. Particular emphasis is made on solution chemistry approaches. We also describe the efforts being made in transforming the CCs into assembled conductors and cables which achieve appealing mechanical and electromagnetic performances for power systems. Finally, we briefly mention some outstanding superconducting power application projects being active at present, in Europe and worldwide, to exemplify the strong advances in reaching the demands to integrate them in a new electrical engineering paradigm.

  9. Mechanistic Study and Characterization of Cold-Sprayed Ultra-High Molecular Weight Polyethylene-Nano-ceramic Composite Coating

    NASA Astrophysics Data System (ADS)

    Ravi, Kesavan; Ichikawa, Yuji; Ogawa, Kazuhiro; Deplancke, Tiana; Lame, Olivier; Cavaille, Jean-Yves

    2016-01-01

    The cold spray deposition of ultra-high molecular weight polyethylene (UHMWPE) powder mixed with nano-alumina, fumed nano-alumina, and fumed nano-silica was attempted on two different substrates namely polypropylene and aluminum. The coatings with UHMWPE mixed with nano-alumina, fumed nano-alumina, and fumed nano-silica were very contrasting in terms of coating thickness. Nano-ceramic particles played an important role as a bridge bond between the UHMWPE particles. Gas temperature and pressure played an important role in the deposition. The differential scanning calorimetry results of the coatings showed that UHMWPE was melt-crystallized after the coating.

  10. Characterization of High-Temperature Abrasive Wear of Cold-Sprayed FeAl Intermetallic Compound Coating

    NASA Astrophysics Data System (ADS)

    Li, Chang-Jiu; Wang, Hong-Tao; Yang, Guan-Jun; Bao, Chong-Gao

    2011-01-01

    FeAl intermetallic compound coating was prepared by cold spraying using a mechanically alloyed Fe(Al) alloy powder followed by post-spray annealing at 950 °C. The high-temperature abrasive wear test was carried out for the FeAl coating at a temperature range from room temperature to 800 °C. The high-temperature abrasive wear of a heat-resistant stainless steel 2520 was performed for comparison. It was observed that the abrasive wear weight loss of FeAl coating was proportional to wear cycles in terms of sample revolutions at the tested temperatures. It was found that with the increase of the test temperature higher than 400 °C, the wear rate of cold-sprayed FeAl coating decreased with the increase of test temperature, while the wear rate of the heat-resistant steel increased significantly. The results indicate that the high-temperature abrasive wear resistance of the cold-sprayed FeAl intermetallic coating increased with the increase of the wear temperature in a temperature range from 400 to 800 °C. The wear resistance of cold-sprayed FeAl coating was higher than that of heat-resistant 2520 stainless steel under 800 °C by a factor of 3.

  11. Vibration analysis of hard-coated composite beam considering the strain dependent characteristic of coating material

    NASA Astrophysics Data System (ADS)

    Sun, W.; Liu, Y.

    2016-08-01

    The strain dependent characteristics of hard coatings make the vibration analysis of hard-coated composite structure become a challenging task. In this study, the modeling and the analysis method of a hard-coated composite beam was developed considering the strain dependent characteristics of coating material. Firstly, based on analyzing the properties of hard-coating material, a high order polynomial was adopted to characterize the strain dependent characteristics of coating materials. Then, the analytical model of a hard-coated composite beam was created by the energy method. Next, using the numerical method to solve the vibration response and the resonance frequencies of the composite beam, a specific calculation flow was also proposed. Finally, a cantilever beam coated with MgO + Al2O3 hard coating was chosen as the study case; under different excitation levels, the resonance region responses and the resonance frequencies of the composite beam were calculated using the proposed method. The calculation results were compared with the experiment and the linear calculation, and the correctness of the created model was verified. The study shows that compared with the general linear calculation, the proposed method can still maintain an acceptable precision when the excitation level is larger.

  12. Vibration analysis of hard-coated composite beam considering the strain dependent characteristic of coating material

    NASA Astrophysics Data System (ADS)

    Sun, W.; Liu, Y.

    2016-05-01

    The strain dependent characteristics of hard coatings make the vibration analysis of hard-coated composite structure become a challenging task. In this study, the modeling and the analysis method of a hard-coated composite beam was developed considering the strain dependent characteristics of coating material. Firstly, based on analyzing the properties of hard-coating material, a high order polynomial was adopted to characterize the strain dependent characteristics of coating materials. Then, the analytical model of a hard-coated composite beam was created by the energy method. Next, using the numerical method to solve the vibration response and the resonance frequencies of the composite beam, a specific calculation flow was also proposed. Finally, a cantilever beam coated with MgO + Al2 O3 hard coating was chosen as the study case; under different excitation levels, the resonance region responses and the resonance frequencies of the composite beam were calculated using the proposed method. The calculation results were compared with the experiment and the linear calculation, and the correctness of the created model was verified. The study shows that compared with the general linear calculation, the proposed method can still maintain an acceptable precision when the excitation level is larger.

  13. 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.

  14. Influence of processing gases on the properties of cold atmospheric plasma SiOxCy coatings

    NASA Astrophysics Data System (ADS)

    Hamze, H.; Jimenez, M.; Deresmes, D.; Beaurain, A.; Nuns, N.; Traisnel, M.

    2014-10-01

    Thin layers of SiOxCy (y = 4-x and 3 ≤ x ≤ 4) were applied using a cold atmospheric plasma torch on glass substrates. The aim was to investigate using Atomic Force Microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (Tof-Sims) the influence of the gases used on the morphology and composition of the deposits. A hexamethyldisilane (HMDS) precursor was injected in post-discharge in an air or nitrogen plasma using a carrier gas (air or nitrogen) and was applied on the substrate previously pre-treated by an air or nitrogen plasma. The carrier gas and plasma gas flows and the distance between the substrate and the plasma torch, the scanning speed, and the precursor flows were kept constant during the study. The gas used during activation pre-treatment showed no particular influence on the characteristics of the deposit. When air is used both as plasma and carrier gas, the coating layer is thicker (96 nm) than when nitrogen is used (64 nm). It was also evidenced that the gas carrying the precursor has little influence on the hydrophobicity of the coating, contrary to the plasma gas. The latter significantly influences the surface characteristics of the coatings. When air is used as plasma gas, a compact coating layer is obtained and the surface has a water contact angle (WCA) of 82°. When nitrogen is used, the deposit is more hydrophobic (WCA of 100°) and the deposit morphology is different. This increase in hydrophobicity could be correlated to the increase of Sisbnd Osbnd C bonds in the upper surface layers evidenced by XPS analyzes. This observation was then confirmed by Tof-Sims analyzes carried out on these thin layers. A uniform distribution of Carbons in the siloxane coating could also be observed using Tof-Sims 2D reconstruction images of cross sections of the deposited layers.

  15. Development of environmentally friendly non-chrome conversion coatings for cold-rolled steel

    NASA Astrophysics Data System (ADS)

    Zhang, Jinming

    Steel producers use various organic and inorganic coatings to protect cold-rolled steel (CRS) sheets from corrosion during shipment and storage. It is well known that CRS sheets can be protected from corrosion by galvanizing, phosphating, chromating, topcoating with organic, or their combinations. The chromate rinsing is particularly effective for preventing white rusting of galvanized steel. But there is an increasing interest in a replacement for the chromating process because of environmental and health concerns. The objective of the present work is to develop a chrome-free conversion coating for steel sheets. Various carboxylic acids and their salts have been studied for coating phosphated electrogalvanized (EG) steel sheets, including 10-undecenoic acid (UA), oleic acid (OA), and other fatty acids such as stearic acid (SA) and palmitic acid (PA). When they were used alone, or subsequently coated with resin, they could produce a highly hydrophobic surface and improve the corrosion resistance. Thiols such as 1-octadecanethiol (ODT) can form a self-assembled monolayer on metal substrates. This close-packed monolayer could provide an excellent corrosion resistance for EG steel sheets. It was capable of withstanding 50˜60 hours of salt spray test (SST) although its thickness was only a few nanometers. The EG steel itself usually started rusting only after 2˜4 hours of salt spray. In another coating system, thiols were mixed with a conventional resin to improve the corrosion resistance of EG steel. This new technique gave 100˜120 hours of corrosion resistance. When the resin was applied directly on EG steel surface, its corrosion resistance was less than 72 hours. It was shown that further optimization of this technique increased the corrosion resistance to 200 hours and more in the standard SST.

  16. Coating analysis of implant materials used in orthopaedic surgery.

    PubMed

    Aksakal, B; Yildirim, O S; Okur, A

    2003-01-01

    Biocompatibility of orthopaedic surgical implants with bone tissue allows adequate osseointegration between the bone and implant. To achieve this, implants are coated with biocompatible materials. The costly plasma spray procedure is routinely used to coat implants but uses high temperatures (over 16,000 degrees C), which affect the surface quality and microstructure of the implant. We analysed the effect of sintering temperature, time and rate on coated and uncoated implants using a dipping method. The effectiveness of synthetic hydrated calcium silicate compound as an interlayer was also investigated, using the dipping method and electrophoretic deposition. Sintering temperature, time and rate all affected the quality of the bond with the coating, but the interlayer bonded effectively with both implant and biocompatible coating. Electrophoretic deposition resulted in imperfect bonding and some irregularity on the substrate surface was seen. This technique may be improved by using coating particles of a smaller size. PMID:14587310

  17. Materials: A compilation. [considering metallurgy, polymers, insulation, and coatings

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Technical information is provided for the properties and fabrication of metals and alloys, as well as for polymeric materials, such as lubricants, coatings, and insulation. Available patent information is included in the compilation.

  18. Progress in advanced high temperature turbine materials, coatings, and technology

    NASA Technical Reports Server (NTRS)

    Freche, J. C.; Ault, G. M.

    1977-01-01

    Material categories as well as coatings and recent turbine cooling developments are reviewed. Current state of the art is identified, and as assessment, when appropriate, of progress, problems, and future directions is provided.

  19. Atomic Layer Deposition for the Conformal Coating of Nanoporous Materials

    DOE PAGESBeta

    Elam, Jeffrey W.; Xiong, Guang; Han, Catherine Y.; Wang, H. Hau; Birrell, James P.; Welp, Ulrich; Hryn, John N.; Pellin, Michael J.; Baumann, Theodore F.; Poco, John F.; et al

    2006-01-01

    Amore » tomic layer deposition ( ALD ) is ideal for applying precise and conformal coatings over nanoporous materials. We have recently used ALD to coat two nanoporous solids: anodic aluminum oxide ( AAO ) and silica aerogels. AAO possesses hexagonally ordered pores with diameters d ∼ 40 nm and pore length L ∼ 70 microns. The AAO membranes were coated by ALD to fabricate catalytic membranes that demonstrate remarkable selectivity in the oxidative dehydrogenation of cyclohexane.dditional AAO membranes coated with ALD Pd films show promise as hydrogen sensors. Silica aerogels have the lowest density and highest surface area of any solid material. Consequently, these materials serve as an excellent substrate to fabricate novel catalytic materials and gas sensors by ALD .« less

  20. 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.

  1. Ni-Al Nanoscale Energetic Materials: Phenomena Involved During the Manufacturing of Bulk Samples by Cold Spray

    NASA Astrophysics Data System (ADS)

    Bacciochini, A.; Bourdon-Lafleur, S.; Poupart, C.; Radulescu, M.; Jodoin, B.

    2014-10-01

    It has been shown that the cold-gas dynamic spraying process, or simply cold spray, is a suitable technique to manufacture nanoscale energetic materials with high reactivity and low porosity. The current study focuses on the Ni-Al system, for which the reactivity has been increased by an initial mechanical activation achieved by the ball-milling technique, leading to lamellar nanostructured composite particles. The consolidation of this nanoscale energetic material using the cold-gas dynamic spray technique permits to retain the feedstock powder nanoscale structure in the coatings, which in turn retain the high reactivity features of the powder. However, it has been noticed that the stagnation temperature during the spray can lead to partial reaction of the highly reactive feedstock powder, which directly influences the reactivity of the coatings. In this study, different stages of the spray process were investigated: (i) the in-flight behavior of the nanoscale energetic material (powder) at different stagnation temperatures (from 300 to 800 °C); (ii) the substrate-temperature evolution as the function of gas temperature; and (iii) the impact of the powder on the substrate, related to particle's velocity and its influence on the nanostructure of the particles.

  2. 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.

  3. Neutron-Absorbing Coatings for Safe Storage of Fissile Materials with Enhanced Shielding & Criticality Safety

    SciTech Connect

    Choi, J; Farmer, J; Lee, C; Fischer, L; Boussoufi, M; Liu, B; Egbert, H

    2007-07-03

    Neutron-absorbing Fe-based amorphous-metal coatings have been developed that are more corrosion resistant than other criticality-control materials, including Al-B{sub 4}C composites, borated stainless steels, and Ni-Cr-Mo-Gd alloys. The presence of relatively high concentration of boron in these coatings not only enhances its neutron-absorption capability, but also enables these coatings to exist in the amorphous state. Exceptional corrosion resistance has been achieved with these Fe-based amorphous-metal alloys through additions of chromium, molybdenum, and tungsten. The addition of rare earth elements such as yttrium has lowered the critical cooling rate of these materials, thereby rendering them more easily processed. Containers used for the storage of nuclear materials, and protected from corrosion through the application of amorphous metal coatings, would have greatly enhanced service lives, and would therefore provide greater long-term safety. Amorphous alloy powders have been successfully produced in multi-ton quantities with gas atomization, and applied to several half-scale spent fuel storage containers and criticality control structures with the high-velocity oxy-fuel (HVOF) thermal spray process. Salt fog testing and neutron radiography of these prototypes indicates that such an approach is viable for the production of large-scale industrial-scale facilities and containers. The use of these durable neutron-absorbing materials to coat stainless steel containers and storage racks, as well as vaults, hot-cell facilities and glove boxes could substantially reduce the risk of criticality in the event of an accident. These materials are particularly attractive for shielding applications since they are fire proof. Additionally, layers of other cold and thermal sprayed materials that include carbon and/or carbides can be used in conjunction with the high-boron amorphous metal coatings for the purpose of moderation. For example, various carbides, including boron

  4. Microstructures and Thermal Properties of Cold-Sprayed Cu-Cr Composite Coatings

    NASA Astrophysics Data System (ADS)

    Kikuchi, S.; Yoshino, S.; Yamada, M.; Fukumoto, M.; Okamoto, K.

    2013-08-01

    Copper-based composites for thermal conductive components were prepared via the cold spray process, and the deposition efficiency and adhesion morphology of feedstock powders on Cu substrate were evaluated. Cu-based composites were fabricated using Cu-Cr mixed powders with their mixture ratio of 20, 35, 50, and 65 mass% Cr onto oxygen-free copper substrate with N2 carrier gas. Cu-Cr composite coatings were investigated for their Cr content ratio, microstructures, and thermal conductivity. The Cr content ratio in the coating was approximately 50-60% of feedstock mixture ratio due to the low formability of the hard particles. Transmission electron microscopy characterizations revealed that an oxygen-rich layer exists at the Cr particle/Cu substrate interface, which contributes to the deposition of the Cr particles. After the heat treatment at 1093 K, the coatings showed denser cross-sectional structures than those before the heat treatment, and the thermal conductivity was improved as a result of the recrystallization of Cu matrix.

  5. Electro-spark deposited coatings for protection of materials

    SciTech Connect

    Johnson, R.N.

    1995-08-01

    Electro-Spark Deposition (ESD) is a micro-welding process that uses short duration, high-current electrical pulses to deposit or alloy a consumable electrode material onto a metallic substrate. The coating is fused (metallurgically bonded) to the substrate with such a low total heat input that the bulk substrate material remains at or near ambient temperature. Rapid solidification of the deposit typically results in an extremely fine-grained deposit that may be amorphous for some materials. Nearly any electrically conductive metal, alloy or cermet can be applied to metallic substrates. The ESD process allows multi-layer coatings to be built-up using different materials to create graded structures or surface compositions that would be difficult to achieve by other means. A series of iron-aluminide coatings based on Fe{sub 3}Al and FeAl in combination with refractory metal diffusion-barrier coatings and supplementary additions of other elements are in corrosion testing at ANL. The most recent FeAl coatings are showing a factor of three better corrosion performance than the best previous coatings. Technology transfer activities are a significant portion of the ESD program effort. Notable successes now include the start-up of a new business to commercialize the ESD technology, major new applications in gas turbine engines and steam turbine blade coatings, and in military, medical, metal-working, and recreational equipment applications.

  6. Fabrication of High-Pressure Cold-Sprayed Coating on Ni-Based Superalloy for High-Temperature Corrosive Conditions

    NASA Astrophysics Data System (ADS)

    Singh, Harminder

    2015-11-01

    The surface behavior of the Ni-based superalloy (composition similar to UNS N06075) is altered in this study by depositing a 298- µm-thick coating for various erosive-corrosive and wear applications at a high temperature. The 50%Ni-50%Cr coating was developed by a high-pressure cold-spraying method. The coating microstructure was studied by various characterization techniques. The unmelted solid particles formed the coating structure, which is homogeneous, dense, hard, and free from cracks, oxides, and other defects. The coating composition and microstructure is suitable for providing protection to the substrate under high-temperature corrosive conditions. The developed coating performed well, with degradation rate of 0.47 mm/year, in the chlorine-based highly corrosive conditions of actual waste incinerator at 900°C.

  7. Microstructure Evolution of Cold-Sprayed Al-Si Alloy Coatings on γ-TiAl During Heat Treatment

    NASA Astrophysics Data System (ADS)

    Wang, Jiqiang; Kong, Lingyan; Li, Tiefan; Xiong, Tianying

    2015-08-01

    This paper investigated the influence of heat treatment on the microstructure of Al-Si alloy coatings on γ-TiAl alloy. The coatings were prepared by cold spraying with Al-12Si and Al-20Si alloy powders as the feedstock, and then the as-sprayed coatings were subjected to heat treatment. The microstructure, chemical composition, and phase transformation of the coatings were studied by SEM, XRD, and EPMA. The diffusing behavior of Al and Si during heat treatment was investigated. The results showed that a silicon-aluminizing coating was formed through the inward diffusion of Al/Si elements into the substrate. The obtained kinetics curve of the formation of silicon-aluminizing coating at 580 °C similarly followed parabolic law.

  8. Biosolvents for Coatings, Resins and Biobased Materials

    SciTech Connect

    Datta, Rathin

    2009-08-31

    With close collaboration with several industrial coatings manufacturers several solvent blends were developed tested and optimized. These were then piloted in the commercial company’s reactors and systems. Three were successfully tested in commercial applications and two of these - Methotate replacement and a specialty ketone replacement were sold in commercial quantities in 2009. Further sales are anticipated in 2010 and the following years.

  9. Enriched aluminide coatings for dispersion strengthened nickel materials

    NASA Technical Reports Server (NTRS)

    Levinstein, M. A.

    1973-01-01

    Improved aluminide/barrier coating combinations for dispersion strengthened nickel materials were investigated. The barrier materials involved alloys with refractory metal content to limit interdiffusion between the coating and the substrate, thereby minimizing void formation. Improved aluminide coatings involved the dispersion of aluminum-rich compounds. Coatings were tested in argon at 1533 K (2300 F) for 100 hours and in cyclic oxidation at 1422 K (2100 F). Two coatings on TDNiCr completed 300 hours of oxidation testing, none on TDNi. Selected coating combinations were evaluated in Mach 1 burner rig testing using JP-4 fuel and air at 1422 K (2100 F) and 1477 K (2200 F) for 350 and 100 hours, respectively. Static oxidation in 1-hour cycles was conducted at 1533 K (2300 F) for 100 hours. For comparison purposes a physical vapor deposition (PVD) NiCrAlY coating was tested concurrently. Only the NiCrA1Y coating survived the 1477 K (2200 F)/100-hour burner rig test and 275 hours of the 350-hour 1422 K (2100 F) test. Elevated temperature exposure reduced room temperature tensile properties but had little effect on elevated temperature properties.

  10. Challenges of non-PFOS top antireflective coating material

    NASA Astrophysics Data System (ADS)

    Hsu, Shu-Hao; Vermeir, Inge; Scholze, Matthias; Voigt, Matthias; Gierth, Janine; Mittermeier, Armelle; Mäge, Iris; Voelkel, Lars

    2008-03-01

    Top anti-reflective coating (TARC) material is very useful in decreasing standing waves and minimizing swing amplitude of critical dimensions (CD) because it can reduce the reflectivity of structures by interference. TARC can also help to control resist defects, improve CD uniformity, and solve CD variation issues caused by post exposure bake (PEB) delay. The perfluorooctyl sulfonate (PFOS) or perfluorooctanoic acid (PFOA) are used as a surfactant in actual TARC materials. They can reduce surface tension to improve the coating performance of TARC. However, PFOS and PFOA are restricted for future applications due to environmental concerns and should be omitted from TARC materials. Therefore, material vendors start working hard on Non-PFOS TARC material development. In this paper, the PEB delay behavior with and without TARC was discussed. The effect of PEB delay is not only related to the pattern density, but also strongly related to resist material. According to the testing results, there are still some issues in Non-PFOS TARC materials such as coating performance, material removing, defect control, and film loss etc. Taking these Non-PFOS TARC materials as examples, Non-PFOS TARC-3 could not be dissolved completely in alkaline developer. There are serious embedded defects of Non-PFOS TARC-2 on patterned wafer. Additionally, Non-PFOS TARC-1 shows an acceptable defect level without TARC baking, but it has poor edge coating and more film loss issues. The issue of poor film coating could be solved by coating recipe modification and also by improvements on the material itself made by the material vendor. Therefore, Non-PFOS TARC-1 without TARC baking can be a candidate for a Non-PFOS TARC process because of its acceptable Litho performances and defect density.

  11. 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.

  12. 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.

  13. Simulated Space Environment Effects on Tether Materials with Protective Coatings

    NASA Technical Reports Server (NTRS)

    Finckenor, Miria M.; Watts, Ed

    2005-01-01

    Atomic oxygen (AO) erodes most organic materials. and ultraviolet radiation embrittles polymers. A previous study indicated untreated polymers such as ultra-high molecular weight polyethylene (UHMWPE) are severely degraded when exposed to AO. This test series was performed to determine the effect of AO and UV on the mechanical integrity of tether materials that were treated with AO-protective coatings. Three coating systems were evaluated for their ability to protect the underlying material from AO erosion. The first coating system is the Photosil surface modification process which incorporates silicon-containing functional groups into the top micron of an organic material. The Photosil process has had favorable results with polyurethane- and epoxy-based thermal control coatings . The second coating system is metallization, in this case nickel. The third coating system is silsesquioxane. The Marshall Space Flight Center Atomic Oxygen Beam Facility (AOBF) was used to simulate low Earth orbit AO of 5 eV energy. In addition, some tether samples were exposed to ultraviolet radiation then evaluated for any changes in mechanical strength. Tether missions, such as a momentum-exchange/electrodynamic reboost (MXER) tether, may benefit from this research.

  14. The Effect of Post-Heat Treatment on Microstructure of 316L Cold-Sprayed Coatings and Their Corrosion Performance

    NASA Astrophysics Data System (ADS)

    Dikici, B.; Yilmazer, H.; Ozdemir, I.; Isik, M.

    2016-04-01

    The combined effects of process gases and post-heat treatment temperature on the microstructure of 316L cold-sprayed coatings on Al5052 substrates have been investigated in this study. The stainless steel coatings were subjected to heat treatment at four different temperatures (250, 500, 750, and 1000 °C) to study the effect of heat treatment. In addition, the corrosion performances of the coatings at different process temperatures have been compared using the potentiodynamic scanning technique. Microstructural characterization of the coatings was carried out using scanning and transmission electron microscopy and x-ray diffraction. The results of present study showed that cold-sprayed stainless steel coatings processed with helium exhibited higher corrosion resistance than those of coatings sprayed with nitrogen process gas. This could partially be attributed to the reduction in porosity level (4.9%) and improvement of particle-particle bonding. In addition, evaluation of the mechanical and microstructural properties of the coatings demonstrated that subsequent heat treatment has major influence on the deposited layers sprayed with He process gas.

  15. Characterization of Cold Sprayed CuCrAl-Coated and Uncoated GRCop-84 Substrates for Space Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Raj, S. V.; Karthikeyan, J.; Lerch, B. A.; Barrett, C.; Garlich, R.

    2007-01-01

    A newly developed Cu-23(wt.%)Cr-5%Al (CuCrAl) alloy is currently being considered as a protective coating for GRCop-84 (Cu-8(at.%)Cr-4%Nb). The coating was deposited on GRCop-84 substrates by the cold spray deposition technique. Cyclic oxidation tests conducted in air on both coated and uncoated substrates between 773 and 1073 K revealed that the coating remained intact and protected the substrate up to 1073 K. No significant weight loss of the coated specimens were observed at 773 and 873 K even after a cumulative cyclic time of 500 h. In contrast, the uncoated substrate lost as much as 80% of its original weight under similar test conditions. Low cycle fatigue tests revealed that the fatigue lives of thinly coated GRCop-84 specimens were similar to the uncoated specimens within the limits of experimental scatter. It is concluded that the cold sprayed CuCrAl coating is suitable for protecting GRCop-84 substrates.

  16. Oxidation resistant slurry coating for carbon-based materials

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  17. Weightless Environment Training Facility (WETF) materials coating evaluation, volume 1

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Weightless Environment Training Facility Material Coating Evaluation project has included preparing, coating, testing, and evaluating 800 test panels of three differing substrates. Ten selected coating systems were evaluated in six separate exposure environments and subject to three tests for physical properties. Substrate materials were identified, the manner of surface preparation described, and exposure environments defined. Exposure environments included immersion exposure, cyclic exposure, and field exposure. Cyclic exposures, specifically QUV-Weatherometer and the KTA Envirotest were found to be the most agressive of the environments included in the study when all three evaluation criteria are considered. This was found to result primarily from chalking of the coatings under ultraviolet (UV) light exposure. Volumes 2 and 3 hold the 5 appendices to this report.

  18. Effect of Microstructure on the Electrical Properties of Nano-Structured TiN Coatings Deposited by Vacuum Cold Spray

    NASA Astrophysics Data System (ADS)

    Wang, Y.-Y.; Liu, Y.; Yang, G.-J.; Feng, J.-J.; Kusumoto, K.

    2010-12-01

    TiN coatings on Al2O3 substrates were fabricated by vacuum cold spray (VCS) process using ultrafine starting ceramic powders of 20 nm in size at room temperature (RT). Microstructure analysis of the samples was carried out by scanning electron microscopy, transmission electron microscopy, and x-ray diffraction. Sheet resistance of the VCS TiN coatings was measured with a four-point probe. The effects of microstructure on the electrical properties of the coatings were investigated. It was found that the sheet resistance and electrical resistivity of TiN coatings were significantly associating with the spray distance, nozzle traversal speed, and deposition chamber pressure. A minimum sheet resistance of 127 Ω was achieved. The microstructural changes can be correlated to the electrical resistivity of TiN coatings.

  19. Effect of Bond Coat Materials on Thermal Fatigue Failure of EB-PVD Thermal Barrier Coatings

    NASA Astrophysics Data System (ADS)

    Yamagishi, Satoshi; Okazaki, Masakazu; Sakaguchi, Motoki; Matsubara, Hideaki

    Effect of MCrAlY bond coat alloy systems on thermal fatigue failure of thermal barrier coatings (TBCs) was investigated, where the TBC specimen consisted of Ni-based superalloy IN738LC substrate, bond coat, and 8 wt.% Y2O3-stabilized ZrO2 (YSZ) top coat. The top coat was fabricated by EB-PVD method with 250 μm in thickness. Three kinds of MCrAlY alloys were studied as the bond coat material. Employing the originally developed test equipment, thermal fatigue tests were carried out, by applying thermal cycles between 400 and 950°C in air. Special attention was paid not only to the failure life of the TBC specimen, but also the underlying failure mechanisms. The experimental results clearly demonstrated that the effect of MCrAlY bond coat alloys on the thermal fatigue life was very significant. Some discussions were made on the experimental results based on the measurements of mechanical and metallurgical properties of the bond coat alloys: i.e., elastic stiffness, thermal expansion coefficient and high temperature oxidation resistance.

  20. OMEGA: A NEW COLD X-RAY SIMULATION FACILITY FOR THE EVALUATION OF OPTICAL COATINGS

    SciTech Connect

    Fisher, J H; Newlander, C D; Fournier, K B; Beutler, D E; Coverdale, C A; May, M J; Tobin, M; Davis, J F; Shiekh, D

    2007-04-27

    We report on recent progress for the development of a new cold X-ray optical test capability using the Omega Facility located at the Laboratory for Laser Energetics (LLE) at the University of Rochester. These tests were done on the 30 kJ OMEGA laser at the Laboratory for Laser Energetics (LLE) at the University of Rochester, Rochester, NY. We conducted a six-shot series called OMEGA II on 14 July 2006 in one eight-hour day (supported by the Defense Threat Reduction Agency). The initial testing was performed using simple protected gold optical coatings on fused silica substrates. PUFFTFT analyses were completed and the specimen's thermal lateral stress and transverse stress conditions were calculated and interpreted. No major anomalies were detected. Comparison of the pre- and posttest reflective measurements coupled with the TFCALC analyses proved invaluable in guiding the analyses and interpreting the observed damage. The Omega facility is a high quality facility for performing evaluation of optical coatings and coupons and provides experience for the development of future National Ignition Facility (NIF) testing.

  1. Deformation of rectangular thin glass plate coated with magnetostrictive material

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoli; Yao, Youwei; Liu, Tianchen; Liu, Chian; Ulmer, M. P.; Cao, Jian

    2016-08-01

    As magnetic smart materials (MSMs), magnetostrictive materials have great potential to be selected as coating materials for lightweight x-ray telescope mirrors due to their capability to tune the mirror profile to the desired shape under a magnetic field. To realize this potential, it is necessary to study the deformation of the mirror substrate with the MSM coating subjected to a localized magnetic field. In this paper, an analytical model is developed to calculate the deformation of rectangular coated samples locally affected by magnetostrictive strains driven by an external magnetic field. As a specific case to validate the model, a square glass sample coated with MSMs is prepared, and its deformation is measured in a designed experimental setup by applying a magnetic field. The measured deformation of the sample is compared with the results calculated from the analytical model. The comparison results demonstrate that the analytical model is effective in calculating the deformation of a coated sample with the localized mismatch strains between the film and the substrate. In the experiments, different shape patterns of surface profile changes are achieved by varying the direction of the magnetic field. The analytical model and the experimental method proposed in this paper can be utilized to further guide the application of magnetostrictive coating to deformable lightweight x-ray mirrors in the future.

  2. Chromium Vaporization Reduction by Nickel Coatings For SOEC Interconnect Materials

    SciTech Connect

    Michael V. Glazoff; Sergey N. Rashkeev; J. Stephen Herring

    2014-09-01

    The vaporization of Cr-rich volatile species from interconnect materials is a major source of degradation that limits the lifetime of planar solid oxide devices systems with metallic interconnects, including Solid Oxide Electrolysis Cells, or SOECs. Some metallic coatings (Ni, Co, and Cu) significantly reduce the Cr release from interconnects and slow down the oxide scale growth on the steel substrate. To shed additional light upon the mechanisms of such protection and find a suitable coating material for ferritic stainless steel materials, we used a combination of first-principles calculations, thermodynamics, and diffusion modeling to investigate which factors determine the quality of the Ni metallic coating at stainless steel interconnector. We found that the Cr migration in Ni coating is determined by a delicate combination of the nickel oxidation, Cr diffusion, and phase transformation processes. Although the formation of Cr2O3 oxide is more exothermic than that of NiO, the kinetic rate of the chromia formation in the coating layer and its surface is significantly reduced by the low mobility of Cr in nickel oxide and in NiCr2O4 spinel. These results are in a good agreement with diffusion modeling for Cr diffusion through Ni coating layer on the ferritic 441 steel substrate.

  3. Coating of metal implant materials with strontium.

    PubMed

    Frank, Matthias J; Walter, Martin S; Tiainen, Hanna; Rubert, Marina; Monjo, Marta; Lyngstadaas, S Petter; Haugen, Håvard J

    2013-11-01

    The aim of this study was to show that cathodic polarization can be used for coating commercial implant surfaces with an immobilized but functional and bioavailable surface layer of strontium (Sr). Moreover, this study assessed the effect of fluorine on Sr-attachment. X-ray photoelectron spectroscopy revealed that addition of fluorine (F) to the buffer during coating increased surface Sr-amounts but also changed the chemical surface composition by adding SrF2 alongside of SrO whereas pre-treatment of the surface by pickling in hydrofluoric acid appeared to hinder Sr-attachment. Assessment of the bio-availability hinted at a positive effect of Sr on cell differentiation given that the surface reactivity of the original surface remained unchanged. Additional SrF2 on the surface appeared to reduce undesired surface contamination while maintaining the surface micro-topography and micro-morphology. Anyhow, this surface modification revealed to create nano-nodules on the surface. PMID:23888353

  4. Cyclic Oxidation Behavior of Cold Sprayed CuCrAl-Coated and Uncoated GRCop-84 Substrates for Space Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Raj, S. V.; Barrett, C.; Karthikeyan, J.; Garlick, R.

    2006-01-01

    A newly developed Cu-23 (wt %) Cr-5%Al (CuCrAl) alloy shown to resist hydridation and oxidation in an as-cast form is currently being considered as a protective coating for GRCop-84, which is an advanced copper alloy containing 8 (at.%) Cr and 4 (at.%) Nb. The coating was deposited on GRCop-84 substrates by the cold spray deposition technique. Cyclic oxidation tests conducted in air on both coated and uncoated substrates between 773 and 1073 K revealed that the coating remained intact and protected the substrate up to 1073 K. No significant weight loss of the coated specimens were observed at 773 and 873 K even after a cumulative cyclic time of 500 h. About a 10 percent weight loss observed at 973 and 1073 K was attributed to the excessive oxidation of the uncoated sides. In contrast, the uncoated substrate lost as much as 80 percent of its original weight under similar test conditions. It is concluded that the cold sprayed CuCrAl coating is suitable for protecting GRCop-84 substrates.

  5. Control of Listeria monocytogenes on cold-smoked salmon using chitosan-based antimicrobial coatings and films.

    PubMed

    Jiang, Zheng; Neetoo, Hudaa; Chen, Haiqiang

    2011-01-01

    The relatively high incidence of Listeria monocytogenes in ready-to-eat (RTE) products such as cold-smoked salmon is of serious concern. The objective of this study was to evaluate the efficacy of chitosan-based edible coatings and films incorporating 3 generally recognized as safe (GRAS) antimicrobials, sodium lactate (SL), sodium diacetate (SD), and potassium sorbate (PS), against L. monocytogenes on cold-smoked salmon. Salmon samples were surface-inoculated with a 5-strain cocktail of Listeria monocytogenes to a final concentration of 4.4 log CFU/cm(2) and then either coated with chitosan solutions or wrapped with chitosan films with or without the 3 antimicrobials. The samples were then vacuum packaged and stored at 4 °C for 30 d. The chitosan coatings with or without the antimicrobials consistently showed higher efficacy against L. monocytogenes than chitosan films having the same compositions. The most effective film treatments, chitosan films containing 1.2% SL/0.25% SD or 2.4% SL, achieved ≥ 1.3 log reductions of L. monocytogenes during the 30 d of refrigerated storage, while the most effective coating treatments, chitosan coatings containing 1.2% SL/0.25% SD or 0.15% PS/0.125% SD, achieved ≥ 2.8 log reductions. Practical Application: This study shows that chitosan-based edible coatings and films hold promise and can potentially assist fishery industries in their efforts to control L. monocytogenes. PMID:21535689

  6. Face Coat Materials Through Sessile Drop and Investment Casting Methods

    NASA Astrophysics Data System (ADS)

    Cheng, Xu; Yuan, Chen; Blackburn, Stuart; Withey, Paul A.

    2014-06-01

    Investment casting is uniquely suited to the manufacture of Ti alloys for the production of near net-shape components, reducing material waste, and machining costs. Because of the high reactivity of titanium and its based alloy, the molds which are used in the investment casting process require high chemical inertness, which results in them being very costly and non-recyclable. In order to reduce the cost of these molds, traditionally using yttria as the face coat, two alternative molds are developed in this study with face coat materials of Y2O3-Al2O3 and Y2O3-Al2O3-ZrO2. The slurry properties and chemical inertness of the face coats were evaluated for viscosity, thermal expansion, friability, and phase development. The chemical inertness of these two molds were determined using both the sessile drop test and investment casting to identify the levels of interaction with a Ti-45Al-2Mn-2Nb-0.2B alloy. The results illustrated that the molds using Y2O3-Al2O3 and Y2O3-Al2O3-ZrO2 as the face coats both showed excellent sintering properties and chemical inertness when compared to the yttria face coat. They can consequently be used as two alternative face coats for the investment casting of TiAl alloys.

  7. Cold machining of high density tungsten and other materials

    NASA Technical Reports Server (NTRS)

    Ziegelmeier, P.

    1969-01-01

    Cold machining process, which uses a sub-zero refrigerated cutting fluid, is used for machining refractory or reactive metals and alloys. Special carbide tools for turning and drilling these alloys further improve the cutting performance.

  8. Workshop on Extraterrestrial Materials from Cold and Hot Deserts

    NASA Technical Reports Server (NTRS)

    Schultz, Ludolf (Editor); Franchi, Ian A. (Editor); Reid, Arch M. (Editor); Zolensky, Michael E. (Editor)

    2000-01-01

    Since 1969 expeditions from Japan, the United States, and European countries have recovered more than 20,000 meteorite specimens from remote ice fields of Antarctica. They represent approximately 4000-6000 distinct falls, more than all non-Antarctic meteorite falls and finds combined. Recently many meteorite specimens of a new "population" have become available: meteorites from hot deserts. It turned out that suitable surfaces in hot deserts, like the Sahara in Africa, the Nullarbor Plain in Western and South Australia, or desert high plains of the U.S. (e.g., Roosevelt County, New Mexico), contain relatively high meteorite concentrations. For example, the 1985 Catalogue of Meteorites of the British Museum lists 20 meteorites from Algeria and Libya. Today, 1246 meteorites finds from these two countries have been published in MetBase 4.0. Four workshops in 1982, 1985, 1988, and 1989 have discussed the connections between Antarctic glaciology and Antarctic meteorites, and the differences between Antarctic meteorites and modem falls. In 1995, a workshop addressed differences between meteorites from Antarctica, hot deserts, and modem falls, and the implications of possible different parent populations, infall rates, and weathering processes. Since 1995 many more meteorites have been recovered from new areas of Antarctica and hot deserts around the world. Among these finds are several unusual and interesting specimens like lunar meteorites or SNCs of probable martian origin. The Annual Meeting of the Meteoritical Society took place in 1999 in Johannesburg, South Africa. As most of the recent desert finds originate from the Sahara, a special workshop was planned prior to this meeting in Africa. Topics discussed included micrometeorites, which have been collected in polar regions as well as directly in the upper atmosphere. The title "Workshop on Extraterrestrial Materials from Cold and Hot Deserts" was chosen and the following points were emphasized: (1) weathering

  9. Workshop on Extraterrestrial Materials from Cold and Hot Deserts

    NASA Technical Reports Server (NTRS)

    Schultz, Ludolf (Editor); Franchi, Ian A. (Editor); Reid, Arch M. (Editor); Zolensky, Michael E. (Editor)

    1999-01-01

    Since 1969 expeditions from Japan, the United States, and European countries have recovered more than 20,000 meteorite specimens from remote ice fields of Antarctica. They represent approximately 4000-6000 distinct falls, more than all non-Antarctic meteorite falls and finds combined. Recently many meteorite specimens of a new "population" have become available: meteorites from hot deserts. It turned out that suitable surfaces in hot deserts, like the Sahara in Africa, the Nullarbor Plain in Western and South Australia, or desert high plains of the U.S. (e.g., Roosevelt County, New Mexico), contain relatively high meteorite concentrations. For example, the 1985 Catalog of Meteorites of the British Museum lists 20 meteorites from Algeria and Libya. Today, 1246 meteorites finds from these two countries have been published in MetBase 4.0. Four workshops in 1982, 1985, 1988, and 1989 have discussed the connections between Antarctic glaciology and Antarctic meteorites, and the differences between Antarctic meteorites and modern falls. In 1995, a workshop addressed differences between meteorites from Antarctica, hot deserts, and modem falls, and the implications of possible different parent populations, infall rates, and weathering processes. Since 1995 many more meteorites have been recovered from new areas of Antarctica and hot deserts around the world. Among these finds are several unusual and interesting specimens like lunar meteorites or SNCs of probable martian origin. The Annual Meeting of the Meteoritical Society took place in 1999 in Johannesburg, South Africa. As most of the recent desert finds originate from the Sahara, a special workshop was planned prior to this meeting in Africa. Topics discussed included micrometeorites, which have been collected in polar regions as well as directly in the upper atmosphere. The title "Workshop on Extraterrestrial Materials from Cold and Hot Deserts" was chosen and the following points were emphasized: (1) weathering

  10. Gelatin methacrylamide as coating material in cell culture.

    PubMed

    Egger, Michael; Tovar, Günter E M; Hoch, Eva; Southan, Alexander

    2016-01-01

    Unmodified gelatin (uG) is widely used as a coating material in cell culture for improving surface properties. In this study, the authors investigated if gelatin methacrylamide (GM) with a medium degree of methacrylamide modification (GM1.5) and a high degree of methacrylamide modification (GM4) are equally suitable for this purpose. Therefore, gold surfaces were coated with uG, GM1.5, and GM4 by adsorption of the polymers on the surfaces. Coating success was confirmed by spectroscopic ellipsometry, contact angle measurements, surface plasmon resonance spectroscopy (SPRS), and atomic force microscopy (AFM). The authors found that upon adsorption of uG, GM1.5, a nd GM4 on gold, thin films with thicknesses of 2.95 nm, 2.50 nm, and 2.26 nm were formed. The coated surfaces showed advancing contact angles of 46° (uG and GM1.5) and 52° (GM4) without alteration of the surface roughness determined by AFM. Protein adsorption taking place on the coated surfaces was measured during contact of the surfaces with fetal calf serum by SPRS. Protein adsorption on the coated surfaces was reduced by the factor of 6.4 (uG), 5.4 (GM1.5), and 4.6 (GM4) compared to gold surfaces. Human fibroblasts cultured on the surfaces showed excellent viability shown by water soluble tetrazolium salt assay as well as live/dead staining with propidium iodide and fluorescein diacetate. No cytotoxic effects of the GM coated surfaces were observed, giving rise to the conclusion that GMs are suitable materials as coatings in cell culture. PMID:27177620

  11. Fabrication and characterization of modified-hydroxyapatite/polyetheretherketone coating materials

    NASA Astrophysics Data System (ADS)

    Ma, Rui; Fang, Lin; Luo, Zhongkuan; Zheng, Ruisheng; Song, Shenhua; Weng, Luqian; Lei, JinPing

    2014-09-01

    45 wt%-Hydroxyaptite/polyetheretherketone (HA/PEEK) coating materials modified by silane coupling agent (KH560) on PEEK substrate were successfully fabricated by solution casting method and characterized by Fourier transform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD), scanning electron microscopy (SEM), and tensile testing. The modified HA fillers were obtained to be uniformly distributed in the HA/PEEK coating, which has better properties of tensile strength and fracture toughness than those of the unmodified specimen. A good bonding between the composite coating and the PEEK substrate was achieved by solution casting method, resulting in integral-fracture without falling apart or delaminating during tensile loading. The modified specimens dipped into simulated body fluid (SBF) were characterized by SEM, XRD and FTIR, indicating that the bioactivity of the dipped materials was demonstrated more apparent with extending the dipping time. Therefore, the coating materials may become the substitutes for the hard tissues of the human body in the future, which could realize the balance between the mechanical properties and the bioactivity by modifying the structural design of the coating.

  12. Microstructural and Mechanical Evaluation of Laser-Assisted Cold Sprayed Bio-ceramic Coatings: Potential Use for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Tlotleng, Monnamme; Akinlabi, Esther; Shukla, Mukul; Pityana, Sisa

    2015-02-01

    Bio-composite coatings of 20 wt.%, HAP and 80 wt.%, HAP were synthesized on Ti-6Al-4V substrates using LACS technique. The coatings were produced with a laser power of 2.5 kW, powder-laser spot trailing by 5 s. The coatings were analyzed for the microstructures, microhardness, composition, and bio-corrosion using SEM-EDS, XRD, hardness tester, and Metrohm PGSTAT101 machine. SEM images indicated least pores and crack-free coating with dark-spots of Ti-HAP for the 20 wt.%, HAP as opposed to the 80 wt.%, HAP coating which was solid, porous and finely cracked and had semi-melted Ti-HAP particles. The EDS mappings showed high content of HAP for the 80 wt.%, HAP coating. The diffraction patterns were similar, even though the Ti-HAP peak was broader in the 80 wt.%, HAP coating and the HAP intensities were lower for this coating except for the (004) peak. The hardness values taken at the interface inferred that the 80 wt.%, HAP coating was least bonded. It was possible to conclude that when this phase material increased the hardness dropped considerably. The bio-corrosion tests indicated that the presence of HAP in coating leads to a kinetically active coating as opposed to pure titanium coating.

  13. Microstructure and High-Temperature Oxidation Behavior of Cold Gas-sprayed Ni-Al2O3 Coatings

    NASA Astrophysics Data System (ADS)

    Sirvent, P.; Cruz, D.; Múnez, C. J.; Poza, P.

    2016-04-01

    Cermet coatings are widely used for high-temperature industrial applications. This study investigates the effect of high-temperature oxidation on cold gas dynamic-sprayed Ni-Al2O3 coatings. For this purpose, high-temperature oxidation tests were performed at 520 and 640 °C. The selected exposure times were 24, 48, 72, 168, and 336 h. The microstructural evolution during exposure at high temperature was analyzed by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), and x-ray diffraction (XRD). The oxidation kinetics was estimated by thickness measurements. The results show that the coatings protect the substrates against oxidation. In order to study possible changes in the mechanical properties of the system, Vickers microhardness experiments on the coatings and on the 10CrMo9-10 steel substrates were conducted. It was observed that hardness decreased by exposing the specimens to high temperature.

  14. ADVANCED HOT SECTION MATERIALS AND COATINGS TEST RIG

    SciTech Connect

    Scott Reome; Dan Davies

    2004-04-30

    The Hyperbaric Advanced Hot Section Materials & Coating Test Rig program provides design and implementation of a laboratory rig capable of simulating the hot gas path conditions of coal-gas fired industrial gas turbine engines. The principal activity during this reporting period were the evaluation of syngas combustor concepts, the evaluation of test section concepts and the selection of the preferred rig configuration.

  15. Advanced Hot Section Materials and Coatings Test Rig

    SciTech Connect

    Dan Davies

    2004-10-30

    The Hyperbaric Advanced Hot Section Materials & Coating Test Rig program provides design and implementation of a laboratory rig capable of simulating the hot gas path conditions of coal-gas fired industrial gas turbine engines. The principal activities during this reporting period were the continuation of test section detail design and developing specifications for auxiliary systems and facilities.

  16. Hot Corrosion Behavior of Low-Pressure Cold-Sprayed CoNiCrAlY Coatings

    NASA Astrophysics Data System (ADS)

    Zhang, L. W.; Ning, X. J.; Lu, L.; Wang, Q. S.; Wang, L.

    2016-02-01

    CoNiCrAlY coatings were deposited by low-pressure cold spraying and pre-oxidized in a vacuum environment, and its hot corrosion behavior in pure Na2SO4 and 75 wt.% Na2SO4 + 25 wt.% NaCl salts was investigated. The pre-oxidation treatment resulted in the formation of a dense and continuous α-Al2O3 scale on the coating surface. After being corroded for 150 h at 900 °C, the pre-oxidized coating exhibited better corrosion resistance to both salts than the as-sprayed coating. The presence of preformed Al2O3 scale reduced the consumption rate of aluminum, by delaying the formation of internal oxides and sulfides and promoting the formation of a denser and more adherent Al2O3 scale. Moreover, we investigated the corrosion mechanism of cold-sprayed CoNiCrAlY coatings in the two salts and discussed the effect of the pre-oxidation treatment.

  17. Formation of stacked luminescent complex of 8-hydroxyquinoline molecules on hydroxyapatite coating by using cold isostatic pressing.

    PubMed

    Matsuya, Takehiko; Otsuka, Yuichi; Tagaya, Motohiro; Motozuka, Satoshi; Ohnuma, Kiyoshi; Mutoh, Yoshiharu

    2016-01-01

    Cold isostatic pressing successfully formed a chelate complex of 8-hydroxyquinoline (8 Hq) molecules on plasma-sprayed hydroxyapatite (HAp) coating by solid-state reaction. The complex emits a fluorescence peak at approximately 500 nm by UV irradiation. The red shift of the fluorescence was newly observed in the cases of highly compressed complex due to π - π stacking of aromatic ring in the molecular structure of 8 Hq. The immersed complex coating in Simulated Body Fluid (SBF) demonstrated amorphous apatite precipitation and kept its fluorescence property. PMID:26478295

  18. Effect of Pulsed Waterjet Surface Preparation on the Adhesion Strength of Cold Gas Dynamic Sprayed Aluminum Coatings

    NASA Astrophysics Data System (ADS)

    Samson, T.; MacDonald, D.; Fernández, R.; Jodoin, B.

    2015-08-01

    It has been observed that the method of substrate surface preparation can have a profound effect on the adhesion strength of cold-sprayed metallic coatings. In this investigation, pure aluminum powder was sprayed onto aluminum alloy substrates using cold spray. The substrates used in this work had undergone a variety of surface preparations to impart varying degrees of surface roughness. The pulsed waterjet technique was used to increase the substrates' surface roughness beyond what can be achieved using traditional grit blasting procedures. Surfaces prepared using pulsed waterjet resulted in substantial increases in the pure aluminum coating adhesion strength. This increase may be the result of increased mechanical anchoring sites available as well as their favorable geometries. It is hypothesized that compressive residual stress may also contribute to increased adhesion strength.

  19. WC-Co Composite Coating Deposited by Cold Spraying of a Core-Shell-Structured WC-Co Powder

    NASA Astrophysics Data System (ADS)

    Luo, Xiao-Tao; Li, Cheng-Xin; Shang, Fu-Lin; Yang, Guan-Jun; Wang, Yu-Yue; Li, Chang-Jiu

    2015-01-01

    In this study, a core-shell-structured WC-Co powder was used to develop a heterogeneously structured WC-Co coating with tens micrometers of WC-10Co as strengthening phase and Co-rich WC-Co as the binder in order to realize simultaneous strengthening and toughening. Spray powder particles contain WC-10Co core coated with a Co-rich WC-Co shell by mechanical milling. WC-Co coating with dual-scale strengthening phases was deposited by cold spraying. Post-spray annealing was carried out to further modify the coating microstructure. Microstructures of the spray powder and the coating were characterized by SEM. Mechanical properties of the coating in terms of microhardness and fracture toughness were examined. Results show that a biomodal WC-Co coating with a porosity of only 0.7% was deposited by cold spray. The Co-rich matrix phase contains submicrometer-sized carbide and primary hard phase is WC-10Co particles. The measurement yielded a Vickers microhardness of 1493 ± 76.7 HV0.1 for WC-10Co core and 693 ± 47.3 HV0.1 for Co-rich binder phase. After annealed at 900 °C for 5 h, a remarkable increase in fracture toughness from 21.2 ± 3.8 to 35.7±5.2 MPa m-0.5 was achieved while no evident change occurred to the hardness of WC-10Co cores.

  20. Polydimethylsiloxane-based self-healing composite and coating materials

    NASA Astrophysics Data System (ADS)

    Cho, Soo Hyoun

    This thesis describes the science and technology of a new class of autonomic polymeric materials which mimic some of the functionalities of biological materials. Specifically, we demonstrate an autonomic self-healing polymer system which can heal damage in both coatings and bulk materials. The new self-healing system we developed greatly extends the capability of self-healing polymers by introducing tin catalyzed polycondensation of hydroxyl end-functionalited polydimethylsiloxane and polydiethoxysiloxane based chemistries. The components in this system are widely available and comparatively low in cost, and the healing chemistry also remains stable in humid or wet environments. These achievements significantly increase the probability that self-healing could be extended not only to polymer composites but also to coatings and thin films in harsh environments. We demonstrate the bulk self-healing property of a polymer composite composed of a phase-separated PDMS healing agent and a microencapsulated organotin catalyst by chemical and mechanical testing. Another significant research focus is on self-healing polymer coatings which prevent corrosion of a metal substrate after deep scratch damage. The anti-corrosion properties of the self-healing polymer on metal substrates are investigated by corrosion resistance and electrochemical tests. Even after scratch damage into the substrate, the coating is able to heal, while control samples which do not include all the necessary healing components reveal rapid corrosion propagation. This self-healing coating solution can be easily applied to most substrate materials, and is compatible with most common polymer matrices. Self-healing has the potential to extend the lifetime and increase the reliability of thermosetting polymers used in a wide variety of applications ranging from microelectronics to aerospace.

  1. Significant influences of metal reactivity and oxide films at particle surfaces on coating microstructure in cold spraying

    NASA Astrophysics Data System (ADS)

    Li, W.-Y.; Zhang, C.; Wang, H.-T.; Guo, X. P.; Liao, H. L.; Li, C.-J.; Coddet, C.

    2007-01-01

    Based on large amount of experimental observations, the effects of metal reactivity and oxide films at particle surfaces on coating deposition behavior in cold spraying were presented and discussed. The oxygen contents in as-sprayed Ti, Ti-6Al-4V and Al coatings were higher than those in the corresponding starting powders. The obvious flashing jets outside nozzle exit during deposition of Ti and Ti-6Al-4V were caused by the reaction of the particles with oxygen in the entrained or the adopted air. For Ti and Ti-6Al-4V coatings, their porous structures are predominantly attributed to the surface reactivity (defined as reactivity with oxygen). This surface reaction could be helpful for formation of a metallurgical bonding between the deposited particles. For Al, even though it is more reactive than Ti, the oxide films at Al particle surfaces suppress the surface activity.

  2. Evaluation Of Potting Materials For Use In Extreme Cold

    NASA Technical Reports Server (NTRS)

    Acosta, Ernesto

    1992-01-01

    Tests help identify noncracking combinations of materials. Aid evaluation of potting materials for copper coils used at low temperatures to measure magnetic fields. Also determine effects of distribution of microballoons, voids, and porosity. Materials also evaluated for ease of use.

  3. Multi-Material ALE with AMR for Modeling Hot Plasmas and Cold Fragmenting Materials

    NASA Astrophysics Data System (ADS)

    Alice, Koniges; Nathan, Masters; Aaron, Fisher; David, Eder; Wangyi, Liu; Robert, Anderson; David, Benson; Andrea, Bertozzi

    2015-02-01

    We have developed a new 3D multi-physics multi-material code, ALE-AMR, which combines Arbitrary Lagrangian Eulerian (ALE) hydrodynamics with Adaptive Mesh Refinement (AMR) to connect the continuum to the microstructural regimes. The code is unique in its ability to model hot radiating plasmas and cold fragmenting solids. New numerical techniques were developed for many of the physics packages to work efficiently on a dynamically moving and adapting mesh. We use interface reconstruction based on volume fractions of the material components within mixed zones and reconstruct interfaces as needed. This interface reconstruction model is also used for void coalescence and fragmentation. A flexible strength/failure framework allows for pluggable material models, which may require material history arrays to determine the level of accumulated damage or the evolving yield stress in J2 plasticity models. For some applications laser rays are propagating through a virtual composite mesh consisting of the finest resolution representation of the modeled space. A new 2nd order accurate diffusion solver has been implemented for the thermal conduction and radiation transport packages. One application area is the modeling of laser/target effects including debris/shrapnel generation. Other application areas include warm dense matter, EUV lithography, and material wall interactions for fusion devices.

  4. Potential applications of cold sprayed Cu50Ti20Ni30 metallic glassy alloy powders for antibacterial protective coating in medical and food sectors.

    PubMed

    El-Eskandrany, M Sherif; Al-Azmi, Ahmed

    2016-03-01

    Mechanical alloying was utilized for synthesizing of metallic glassy Cu50Ti20Ni30 alloy powders, using a low energy ball milling technique. The metallic glassy powders obtained after 100 h of ball milling had an average particle size of 1.7 mm in diameter and possessed excellent thermal stability, indexed by a relatively high glass transition temperature (358.3 °C) with a wide supercooled liquid region (61 °C). This amorphous phase crystallized into Ti2Cu and CuTiNi2 ordered phases through two overlapped crystallization temperatures at 419.3 °C and 447.5 °C, respectively. The total enthalpy change of crystallization was -4.8 kJ/mol. The glassy powders were employed as feedstock materials to double-face coating the surface of SUS 304 substrate, using cold spraying process under helium gas pressure at 400 °C. This coating material had an extraordinary high nanohardness value of 3.1 GPa. Moreover, it showed a high resistance to wear with a low value of the coefficient of friction ranging from 0.45 to 0.45. Biofilms were grown on 20-mm(2) SUS304 sheets coated coupons inoculated with 1.5 × 10(8) CFU ml(-1)E. coli. Significant biofilm inhibition (p The inhibition of biofilm formation by nanocrystalline powders of Cu-based provides a practical approach to achieve the inhibition of biofilms formation. PMID:26703232

  5. Role of surface coating on cathode materials for lithium-ion batteries.

    SciTech Connect

    Chen, Z.; Qin, Y.; Amine, K.; Sun, Y.-K.

    2010-01-01

    Surface coating of cathode materials has been widely investigated to enhance the life and rate capability of lithium-ion batteries. The surface coating discussed here was divided into three different configurations which are rough coating, core shell structure coating and ultra thin film coating. The mechanism of surface coating in achieving improved cathode performance and strategies to carry out this surface modification is discussed. An outlook on atomic layer deposition for lithium ion battery is also presented.

  6. Advanced Hot Section Materials and Coatings Test Rig

    SciTech Connect

    Dan Davis

    2006-09-30

    Phase I of the Hyperbaric Advanced Hot Section Materials & Coating Test Rig Program has been successfully completed. Florida Turbine Technologies has designed and planned the implementation of a laboratory rig capable of simulating the hot gas path conditions of coal gas fired industrial gas turbine engines. Potential uses of this rig include investigations into environmental attack of turbine materials and coatings exposed to syngas, erosion, and thermal-mechanical fatigue. The principle activities during Phase 1 of this project included providing several conceptual designs for the test section, evaluating various syngas-fueled rig combustor concepts, comparing the various test section concepts and then selecting a configuration for detail design. Conceptual definition and requirements of auxiliary systems and facilities were also prepared. Implementation planning also progressed, with schedules prepared and future project milestones defined. The results of these tasks continue to show rig feasibility, both technically and economically.

  7. Electrospun Nanofiber Coating of Fiber Materials: A Composite Toughening Approach

    NASA Technical Reports Server (NTRS)

    Kohlman, Lee W.; Roberts, Gary D.

    2012-01-01

    Textile-based composites could significantly benefit from local toughening using nanofiber coatings. Nanofibers, thermoplastic or otherwise, can be applied to the surface of the fiber tow bundle, achieving toughening of the fiber tow contact surfaces, resulting in tougher and more damage-resistant/tolerant composite structures. The same technique could also be applied to other technologies such as tape laying, fiber placement, or filament winding operations. Other modifications to the composite properties such as thermal and electrical conductivity could be made through selection of appropriate nanofiber material. Control of the needle electric potential, precursor solution, ambient temperature, ambient humidity, airflow, etc., are used to vary the diameter and nanofiber coating morphology as needed. This method produces a product with a toughening agent applied to the fiber tow or other continuous composite precursor material where it is needed (at interfaces and boundaries) without interfering with other composite processing characteristics.

  8. Mixed composition materials suitable for vacuum web sputter coating

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.; Dever, Joyce A.; Bruckner, Eric J.; Walters, Patricia; Hambourger, Paul D.

    1996-01-01

    Ion beam sputter deposition techniques were used to investigate simultaneous sputter etching of two component targets so as to produce mixed composition films. Although sputter deposition has been largely confined to metals and metal oxides, at least one polymeric material, poly-tetra-fluorethylene, has been demonstrated to produce sputtered fragments which repolymerize upon deposition to produce a highly cross-linked fluoropolymer resembling that of the parent target Fluoropolymer-filled silicon dioxide and fluoropolymer-filled aluminum oxide coatings have been deposited by means of ion beam sputter coat deposition resulting in films having material properties suitable for aerospace and commercial applications. The addition of fluoropolymer to silicon dioxide films was found to increase the hydrophobicity of the resulting mixed films; however, adding fluoropolymer to aluminum oxide films resulted in a reduction in hydrophobicity, thought to be caused by aluminum fluoride formation.

  9. PH and Electrochemical Responsive Materials for Corrosion Smart Coating Applications

    NASA Technical Reports Server (NTRS)

    Li, Wenyan; Calle, Luz M.

    2008-01-01

    Corrosion is a costly issue for military operations and civil industries. While most corrosion initiates from localized corrosion form, such as pitting, failure directly caused by localized corrosion is the most dangerous kind, because it is difficult to anticipate and prevent, occurs very suddenly and can be catastrophic. One way of preventing these failures is with a coating that can detect and heal localized corrosion. pH and other electrochemical changes are often associated with localized corrosion, so it is expected that materials that are pH or otherwise electrochemical responsive can be used to detect and control corrosion. This paper will review various pH and electrochemical responsive materials and their potential applications in corrosion smart coatings. Current research results in this field will also be reported.

  10. ADVANCED HOT SECTION MATERIALS AND COATINGS TEST RIG

    SciTech Connect

    Scott Reome; Dan Davies

    2004-01-01

    The Hyperbaric Advanced Hot Section Materials & Coating Test Rig program initiated this quarter, provides design and implementation of a laboratory rig capable of simulating the hot gas path conditions of coal-gas fired industrial gas turbine engines. The principle activity during this first reporting period were preparing for and conducting a project kick-off meeting, working through plans for the project implementation, and beginning the conceptual design of the test section.

  11. 49 CFR 195.559 - What coating material may I use for external corrosion control?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false What coating material may I use for external...) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Corrosion Control § 195.559 What coating material may I use for external corrosion control? Coating material for external corrosion control...

  12. Materials Selection for the HFIR Cold Neutron Source

    SciTech Connect

    Farrell, K.

    2001-08-24

    In year 2002 the High Flux Isotope Reactor (HFIR) will be fitted with a source of cold neutrons to upgrade and expand its existing neutron scattering facilities. The in-reactor components of the new source consist of a moderator vessel containing supercritical hydrogen gas moderator at a temperature of 20K and pressure of 15 bar, and a surrounding vacuum vessel. They will be installed in an enlarged beam tube located at the site of the present horizontal beam tube, HB-4; which terminates within the reactor's beryllium reflector. These components must withstand exceptional service conditions. This report describes the reasons and factors underlying the choice of 6061-T6 aluminum alloy for construction of the in-reactor components. The overwhelming considerations are the need to minimize generation of nuclear heat and to remove that heat through the flowing moderator, and to achieve a minimum service life of about 8 years coincident with the replacement schedule for the beryllium reflector. 6061-T6 aluminum alloy offers the best combination of low nuclear heating, high thermal conductivity, good fabricability, compatibility with hydrogen, superior cryogenic properties, and a well-established history of satisfactory performance in nuclear environments. These features are documented herein. An assessment is given of the expected performance of each component of the cold source.

  13. [Blood compatibility of two novel polyurethane coating materials].

    PubMed

    Yu, Guanhua; Ji, Jian; Wang, Dongan; Feng, Linxian; Shen, Jiacong

    2004-04-01

    Amphiphilic coupling-polymer of stearyl poly (ethylene oxide)-co-4, 4'-methylendiphenyl diisocyanate-co-stearyl poly(ethylene oxide), MSPEO, was specially designed as surface-modifying additives. The blends of MSPEO in both polyether urethane (PEU) and chitosan(Chi), as the coating materials for intravascular device were investigated. Two kinds of static clotting time tests, plasma recalcification time (PRT) and prothrombin time(PT), as well as the static platelet adhesion experiment were carried out. And the dynamic anti-coagulation experiment was performed with a closed-loop tubular system under a blood shear rate of 1,500 s-1. The results demonstrate that both blend coatings can improve the anti-coagulation of polyurethane greatly and will not lead to hemolysis, and that more platelets adhere to the surface modified by Chi-MSPEO blend coating as compared with those adhere to the surface modified by PEU-MSPEO blend coating. The surface modified by Chi-MSPEO has longer PRT, whereas the surface modified by PEU-MSPEO has longer PT. PMID:15143535

  14. Overview of Materials and Power Applications of Coated Conductors Project

    NASA Astrophysics Data System (ADS)

    Shiohara, Yuh; Taneda, Takahiro; Yoshizumi, Masateru

    2012-01-01

    There are high expectations for coated conductors in electric power applications such as superconducting magnetic energy storage (SMES) systems, power cables, and transformers owing to their ability to contribute to stabilizing and increasing the capacity of the electric power supply grid as well as to reducing CO2 emission as a result of their high critical-current characteristics. Research and development has been performed on wires/tapes and electric power devices worldwide. The Materials and Power Applications of Coated Conductors (M-PACC) Project is a five-year national project in Japan started in 2008, supported by the Ministry of Economy, Trade and Industry (METI) and the New Energy and Industrial Technology Development Organization (NEDO), to develop both coated conductors that meet market requirements and basic technologies for the above-mentioned power applications using coated conductors. In this article, research and development results are reviewed and compared with the interim/final targets of the project, and future prospects are discussed.

  15. Spacecraft materials guide. [including: encapsulants and conformal coatings; optical materials; lubrication; and, bonding and joining processes

    NASA Technical Reports Server (NTRS)

    Staugaitis, C. L. (Editor)

    1975-01-01

    Materials which have demonstrated their suitability for space application are summarized. Common, recurring problems in encapsulants and conformal coatings, optical materials, lubrication, and bonding and joining are noted. The subjects discussed include: low density and syntactic foams, electrical encapsulants; optical glasses, interference filter, mirrors; oils, greases, lamillar lubricants; and, soldering and brazing processes.

  16. Nanoindentation and nanoscratching of hard coating materials for magnetic disks

    SciTech Connect

    Tsui, T.Y.; Pharr, G.M.; Oliver, W.C.; Chung, Y.W.; Cutiongco, E.C.; Bhatia, C.S.; White, R.L.; Rhodes, R.L.; Gorbatkin, S.M.

    1994-12-31

    Nanoindentation and nanoscratching experiments have been performed to assess the mechanical and tribological behavior of three thin film materials with potential application as wear resistant coatings for magnetic disk storage: (1) hydrogenated-carbon (CHx); (2) nitrogenated-carbon (CNx); and (3) boron suboxide (BOx). The hardness and elastic modulus were measured using nanoindentation. Ultra-low load nanoscratching tests were performed to assess the relative scratch resistance of the films and measure their friction coefficients. The mechanical and tribological performance of the three materials are discussed and compared.

  17. Sputtering - A vacuum deposition method for coating material.

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1972-01-01

    The sputtering method is discussed in terms of the unique features which sputter offers in depositing coatings. These features include versatility, momentum transfer, configuration of target, precise controls, and a relatively slow deposition rate. Sputtered films are evaluated in terms of adherence, coherence, and the internal stresses. The observed strong adherence is attributed to the high kinetic energies of the sputtered material, sputter etched surface, and the submicroscopic particle size. Film thickness can be controlled to a millionth of a centimeter. Very adherent films of sputtered PTFE (teflon) can be deposited in a single operation on any type of material and on any geometrical configuration.

  18. Coronary Stent Materials and Coatings: A Technology and Performance Update.

    PubMed

    O'Brien, Barry; Zafar, Haroon; Ibrahim, Ahmad; Zafar, Junaid; Sharif, Faisal

    2016-02-01

    This paper reviews the current state of the art for coronary stent materials and surface coatings, with an emphasis on new technologies that followed on from first-generation bare metal and drug-eluting stents. These developments have been driven mainly by the need to improve long term outcomes, including late stent thrombosis. Biodegradable drug-eluting coatings aim to address the long term effects of residual durable polymer after drug elution; the SYNERGY, BioMatrix, and Nobori stents are all promising devices in this category, with minimal polymer through the use of abluminal coatings. Textured stent surfaces have been used to attached drug directly, without polymer; the Yukon Choice and BioFreedom stents have some promising data in this category, while a hydroxyapatite textured surface has had less success. The use of drug-filled reservoirs looked promising initially but the NEVO device has experienced both technical and commercial set-backs. However this approach may eventually make it to market if trials with the Drug-Filled Stent prove to be successful. Non-pharmacological coatings such as silicon carbide, carbon, and titanium-nitride-oxide are also proving to have potential to provide better performance than BMS, without some of the longer term issues associated with DES. In terms of biological coatings, the Genous stent which promotes attachment of endothelial progenitor cells has made good progress while gene-eluting stents still have some practical challenges to overcome. Perhaps the most advancement has been in the field of biodegradable stents. The BVS PLLA device is now seeing increasing clinical use in many complex indications while magnesium stents continue to make steady advancements. PMID:26139297

  19. Cracking of coated materials under transient thermal stresses

    NASA Technical Reports Server (NTRS)

    Rizk, A. A.; Erdogan, F.

    1989-01-01

    The crack problem for a relatively thin layer bonded to a very thick substrate under thermal shock conditions is considered. The effect of surface cooling rate is studied by assuming the temperature boundary condition to be a ramp function. Among the crack geometries considered are the edge crack in the coating layer, the broken layer, the edge crack going through the interface, the undercoat crack in the substrate and the embedded crack crossing the interface. The primary calculated quantity is the stress intensity factor at various singular points and the main variables are the relative sizes and locations of cracks, the time, and the duration of the cooling ramp. The problem is solved and rather extensive results are given for two material pairs, namely a stainless steel layer welded on a ferritic medium and a ceramic coating on a steel substrate.

  20. Cracking of coated materials under transient thermal stresses

    SciTech Connect

    Rizk, A.A.; Erdogan, F. )

    1989-01-01

    The crack problem for a relatively thin layer bonded to a very thick substrate under thermal shock conditions is considered. The effect of surface cooling rate is studied by assuming the temperature boundary condition to be a ramp function. Among the crack geometries considered are the edge crack in the coating layer, the broken layer, the edge crack going through the interface, the undercoat crack in the substrate and the embedded crack crossing the interface. The primary calculated quantity is the stress intensity factor at various singular points and the main variables are the relative sizes and locations of cracks, the time, and the duration of the cooling ramp. The problem is solved and rather extensive results are given for two material pairs, namely a stainless steel layer welded on a ferritic medium and a ceramic coating on a steel substrate. 12 refs.

  1. Cracking of coated materials under transient thermal stresses

    NASA Technical Reports Server (NTRS)

    Rizk, A. A.; Erdogan, Fazil

    1988-01-01

    The crack problem for a relatively thin layer bonded to a very thick substrate under thermal shock conditions is considered. The effect of surface cooling rate is studied by assuming the temperature boundary condition to be a ramp function. Among the crack geometries considered are the edge crack in the coating layer, the broken layer, the edge crack going through the interface, the undercoat crack in the substrate and the embedded crack crossing the interface. The primary calculated quantity is the stress intensity factor at various singular points and the main variables are the relative sizes and locations of cracks, the time, and the duration of the cooling ramp. The problem is solved and rather extensive results are given for two material pairs, namely a stainless steel layer welded on a ferritic medium and a ceramic coating on a steel substrate.

  2. Impact Testing of Stainless Steel Material at Cold Temperatures

    SciTech Connect

    Spencer D. Snow; D. Keith Morton; Robert K. Blandford

    2008-07-01

    Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates during accidental drop events. Mechanical characteristics of these base materials and their welds under dynamic loads in the strain rate range of concern are not well documented. However, a previous paper [1] reported on impact testing and analysis results performed at the Idaho National Laboratory using 304/304L and 316/316L stainless steel base material specimens at room and elevated temperatures. The goal of the work presented herein is to add recently completed impact tensile testing results at -20 degrees F conditions for dual-marked 304/304L and 316/316L stainless steel material specimens (hereafter referred to as 304L and 316L, respectively). Recently completed welded material impact testing at -20 degrees F, room, 300 degrees F, and 600 degrees F is also reported. Utilizing a drop-weight impact test machine and 1/4-inch to 1/2-inch thick dog-bone shaped test specimens, the impact tests achieved strain rates in the 4 to 40 per second range, depending upon the material temperature. Elevated true stress-strain curves for these materials reflecting varying strain rates and temperatures are presented herein.

  3. New Materials for Structural Composites and Protective Coatings

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The objective of this Phase I project was to create novel conductive materials that are lightweight and strong enough for multiple ground support equipment and Exploration applications. The long-term goal is to combine these materials within specially designed devices to create composites or coatings with diagnostic capabilities, increased strength, and tunable properties such as transparency, electroluminescence, and fire resistance. One such technology application is a smart windows system. In such a system, the transmission of light through a window is controlled by electrical power. In the future, these materials may also be able to absorb sunlight and convert it into electrical energy to produce light, thereby creating a self-sufficient lighting system. This experiment, conducted in collaboration with the Georgia Institute of Technology, demonstrated enhancements in fabricating fiber materials from carbon nanotubes (CNT). These nanotubes were grown as forests in an ultra-high-purity chemical vapor deposition (CVD) furnace and then drawn, using novel processing techniques, into fibers and yarns that would be turned into filaments. This work was submitted to the Journal of Advanced Functional Materials. The CNT fibers were initially tested as filament materials at atmospheric pressure; however, even under high current loads, the filaments produced only random sparking. The CNT fibers were also converted into transparent, hydrophobic, and conductive sheets. Filament testing at low vacuum pressures is in progress, and the technology will be enhanced in 2008. As initial proof of the smart-windows application concept, the use of CNT sheets as composites/ protective coatings was demonstrated in collaboration with Nanocomp Technologies of Concord, New Hampshire.

  4. New Barrier Coating Materials for PV Module Backsheets: Preprint

    SciTech Connect

    Barber, G. D.; Jorgensen, G. J.; Terwilliger, K.; Glick, S. H.; Pern, J.; McMahon, T. J.

    2002-05-01

    This conference paper describes the high moisture barrier high resistivity coatings on polyethylene terepthalate (PET) have been fabricated and characterized for use in PV module back sheet applications. These thin film barriers exhibit water vapor transmission rates (WVTR) as low as 0.1 g/m2-day at 37.8 C and have shown excellent adhesion (> 10 N/mm) to both ethylene vinyl acetate (EVA) and PET even after filtered xenon arc lamp UV exposure. The WVTR and adhesion values for this construction are compared to and shown to be superior to candidate polymeric backsheet materials.

  5. Influence of Pre-Heated Al 6061 Substrate Temperature on the Residual Stresses of Multipass Al Coatings Deposited by Cold Spray

    NASA Astrophysics Data System (ADS)

    Rech, Silvano; Trentin, Andrea; Vezzù, Simone; Legoux, Jean-Gabriel; Irissou, Eric; Guagliano, Mario

    2011-01-01

    In this work, the influence of the substrate temperature on the deposition efficiency, on the coating properties and residual stress was investigated. Pure Al coatings were deposited on Al 6061 alloy substrates using a CGT Kinetics 3000 cold spray system. The substrate temperature was in a range between 20 (room temperature) and 375 °C and was kept nearly constant during a given deposition while all the other deposition parameters were unchanged. The deposited coatings were quenched in water (within 1 min from the deposition) and then characterized. The residual stress was determined by Almen gage method, Modified Layer Removal Method, and XRD in order to identify both the mean coating stress and the stress profile through the coating thickness from the surface to the coating-substrate interface. The residual stress results obtained by these three methods were compared and discussed. The coating morphology and porosity were investigated using optical and scanning electron microscopy.

  6. Nonaqueous composition for slip casting or cold forming refractory material into solid shapes

    SciTech Connect

    Montgomery, L.C.

    1993-08-24

    A composition is described for slip casting or cold forming non-oxide refractory material(s) into solid shape comprising finely divided solid refractory materials selected from the group consisting of metal boride, refractory carbide, nitride, silicide and a refractory metal of tungsten, molybdenum, tantalum and chromium suspended in a nonaqueous liquid slip composition consisting essentially of a deflocculent composed of a vinyl chloride-vinyl acetate resin dissolved in an organic solvent.

  7. Effect of Heat Treatment on the Microstructure and Mechanical Properties of Stainless Steel 316L Coatings Produced by Cold Spray for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    AL-Mangour, Bandar; Vo, Phuong; Mongrain, Rosaire; Irissou, Eric; Yue, Stephen

    2014-04-01

    In this study, the effects of heat treatment on the microstructure and mechanical properties of cold sprayed stainless steel 316L coatings using N2 and He as propellant gases were investigated. Powder and coating characterizations, including coating microhardness, coating porosity, and XRD phase analysis were performed. It was found that heat treatment reduced porosity, improved inter-particle bonding, and increased ductility. XRD results confirmed that no phase transformation occurred during deposition. Significant increase in UTS and ductility was observed for the annealed specimens obtained with nitrogen propellant, whereas little changes were observed for the helium propellant produced specimen.

  8. Thermal/environmental barrier coating system for silicon-based materials

    NASA Technical Reports Server (NTRS)

    Spitsberg, Irene T. (Inventor); Wang, Hongyu (Inventor)

    1999-01-01

    A coating system for a substrate containing a silicon-based material, such as silicon carbide-containing ceramic matrix materials containing silicon carbide and used to form articles exposed to high temperatures, including the hostile thermal environment of a gas turbine engine. The coating system includes a layer of barium strontium aluminosilicate (BSAS) as a bond coat for a thermal-insulating top coat. As a bond coat, the BSAS layer serves to adhere the top coat to a SiC-containing substrate. The BSAS bond coat exhibits sufficient environmental resistance such that, if the top coat should spall, the BSAS bond coat continues to provide a level of environmental protection to the underlying SiC-containing substrate.

  9. Workshop on Extraterrestrial Materials from Cold and Hot Deserts

    NASA Technical Reports Server (NTRS)

    Buchanan, Paul C.

    1999-01-01

    The workshop was held July 6-8, 1999 before the Meteoritical Society meeting in Johannesburg, South Africa. The venue was Kwa Maritane Resort in the Pilanesburg Game Reserve. Conveners were Ludolf Schultz (Chair, MPI fur Chemie), Ian Franchi (Open University), Arch Reid (University of Houston), and Mike Zolensky (NASA JSC). Extended abstracts will be published as an LPI Technical Report. In the first session, Marvin discussed three African iron meteorites: Cape of Good Hope, Gibeon, and Hoba. Grady presented a statistical analysis of meteorites from hot and cold deserts. Wasson discussed types of Antarctic iron meteorites. Several presentations characterized populations of meteorites from individual desert areas: Libyan Desert (Weber et al.), Nullarbor Region (Bevan et al.), and Mojave Desert (Kring et al. and Verish et al). Pairing among EET87503-group howardites was discussed by Buchanan et al. Based on 14C terrestrial ages of Allan Hills ordinary chondrites, Bland et al. suggested that ice flow may be the principal sink for Antarctic meteorites. The effects of preterrestrial and terrestrial alteration were considered in the second session. Nakamura et al. and Lipschutz discussed asteroidal metamorphism of carbonaceous chondrites. Zolensky presented evidence for preterrestrial halide and sulfide in meteorites. Crozaz and Wadhwa described terrestrial alteration of Dar al Gani 476. Welten and Nishiizumi discussed terrestrial weathering of chondrites from Frontier Mountain, Antarctica. Most of the third session dealt with terrestrial meteorite ages. Based on 14C-10Be ages, Jull et al. discussed the exponential decay in numbers of meteorites with increased age. Nishiizumi et al. concluded that some Allan Hills meteorites have much older terrestrial ages than any meteorites from Lewis Cliffs. Welten et al. discussed terrestrial ages determined by 41Ca/36CI of metal separates from hot desert meteorites. Based on a comparison with large IDPs, Flynn et al. suggested that

  10. Technical evaluation of Russian aircraft stealth coating and structural materials

    SciTech Connect

    Gac, F.D.; Young, A.T. Jr.; Migliori, A.

    1996-10-01

    Treating aircraft, missiles, and ships with materials that absorb electromagnetic energy continues to be an important technique for reducing a vehicle`s radar cross section (RCS) and improving tis combat effectiveness and survivability. Work at the Russian Scientific Center for Applied Problems in Electrodynamics (SCAPE) has produced and experimentally validated an accurate predictor of the interaction of electromagnetic radiation with discontinuous composite materials consisting of magnetic and/or dielectric particles dispersed in a non-conductive matrix (i.e. percolation systems). The primary purpose of this project was to analyze rf-absorbing coatings and validate manufacturing processes associated with the Russian percolation system designs. An additional objective was to apply the percolation methodology toward a variety of civilian applications by transferring the technology to US industry.

  11. Processing of fused silicide coatings for carbon-based materials

    NASA Technical Reports Server (NTRS)

    Smialek, J. L.

    1982-01-01

    The processing and oxidation resistance of fused Al-Si and Ni-Si slurry coatings on ATJ graphite was studied. Ni-Si coatings in the 70 to 90 percent Si range were successfully processed to melt, wet, and bond to the graphite. The molten coatings also infiltrated the porosity in graphite and reacted with it to form SiC in the coating. Cyclic oxidation at 1200 C showed that these coatings were not totally protective because of local attack of the substrate, due to the extreme thinness of the coatings in combination with coating cracks.

  12. Cold neutron depth profiling of lithium-ion battery materials

    NASA Astrophysics Data System (ADS)

    Lamaze, G. P.; Chen-Mayer, H. H.; Becker, D. A.; Vereda, F.; Goldner, R. B.; Haas, T.; Zerigian, P.

    We report the characterization of two thin-film battery materials using neutron techniques. Neutron depth profiling (NDP) has been employed to determine the distribution of lithium and nitrogen simultaneously in lithium phosphorous oxynitride (LiPON) deposited by ion beam assisted deposition (IBAD). The depth profiles are based on the measurement of the energy of the charged particle products from the 6Li(n,α) 3H and 14N(n,p) 14C reactions for lithium and nitrogen, respectively. Lithium at the level of 10 22 atoms/cm 3 and N of 10 21 atoms/cm 3, distributed in the film thickness on the order of 1 μm, have been determined. This information provides insights into nitrogen incorporation and lithium concentration in the films under various fabrication conditions. NDP of lithium has also been performed on IBAD LiCoO 2 films, in conjunction with instrumental neutron activation analysis (INAA) to determine the cobalt concentration. The Li/Co ratio thus obtained serves as an ex situ control for the thin-film evaporation process. The non-destructive nature of the neutron techniques is especially suitable for repeated analysis of these materials and for actual working devices.

  13. Splat Formation and Adhesion Mechanisms of Cold Gas-Sprayed Al Coatings on Al2O3 Substrates

    NASA Astrophysics Data System (ADS)

    Drehmann, R.; Grund, T.; Lampke, T.; Wielage, B.; Manygoats, K.; Schucknecht, T.; Rafaja, D.

    2014-01-01

    The metallization of ceramics by means of cold gas spraying (CGS) has been in the focus of numerous publications in the recent past. However, the bonding mechanism of metallic coatings on non-ductile substrates is still not fully understood. Former investigations of titanium coatings deposited on corundum revealed that a combination of recrystallization induced by adiabatic shear processes and hetero-epitaxial growth might be responsible for the high adhesion strengths of coatings applied on smooth ceramic surfaces. In the present work, the interface formation between CGS aluminum and alumina substrates is examined for different particle sizes and substrate temperatures. Furthermore, the influence of subsequent heat treatment on tensile strength and hardness is investigated. The splat formation of single particles is examined by means of scanning electron microscopy, while a high resolution transmission electron microscope is used to study the Al/Al2O3 interface. First results suggest that mechanical interlocking is the primary adhesion mechanism on polycrystalline substrates having the roughness in sub-micrometer range, while the heteroepitaxy between Al and Al2O3 can be considered as the main bonding mechanism for single-crystalline sapphire (α-Al2O3) substrates with the surface roughness in nanometer range. The heteroepitaxial growth is facilitated by deformation-induced recrystallisation of CGS aluminum.

  14. Surface modification of polymeric materials by cold atmospheric plasma jet

    NASA Astrophysics Data System (ADS)

    Kostov, K. G.; Nishime, T. M. C.; Castro, A. H. R.; Toth, A.; Hein, L. R. O.

    2014-09-01

    In this work we report the surface modification of different engineering polymers, such as, polyethylene terephthalate (PET), polyethylene (PE) and polypropylene (PP) by an atmospheric pressure plasma jet (APPJ). It was operated with Ar gas using 10 kV, 37 kHz, sine wave as an excitation source. The aim of this study is to determine the optimal treatment conditions and also to compare the polymer surface modification induced by plasma jet with the one obtained by another atmospheric pressure plasma source - the dielectric barrier discharge (DBD). The samples were exposed to the plasma jet effluent using a scanning procedure, which allowed achieving a uniform surface modification. The wettability assessments of all polymers reveal that the treatment leads to reduction of more than 40° in the water contact angle (WCA). Changes in surface composition and chemical bonding were analyzed by x-ray photoelectron spectroscopy (XPS) and Fourier-Transformed Infrared spectroscopy (FTIR) that both detected incorporation of oxygen-related functional groups. Surface morphology of polymer samples was investigated by Atomic Force Microscopy (AFM) and an increase of polymer roughness after the APPJ treatment was found. The plasma-treated polymers exhibited hydrophobic recovery expressed in reduction of the O-content of the surface upon rinsing with water. This process was caused by the dissolution of low molecular weight oxidized materials (LMWOMs) formed on the surface as a result of the plasma exposure.

  15. Powder diffraction in materials science using the KENS cold-neutron source

    SciTech Connect

    Kamiyama, T.; Oikawa, K.; Akiba, E.

    1997-12-01

    Since superconductivity fever spread around the world, neutron powder diffraction has become very popular and been widely used by crystallographers, physicists, chemists, mineralogists, and materials scientists. The purpose of present paper is to show, firstly, important characteristics of time-of-flight TOF powder diffraction using cold-neutron source in the study of materials science, and, secondly, recent studies on the structure and function of batteries at the Neutron Science Laboratory (KENS) in the High Energy Accelerator Research Organization (KEK).

  16. Material Properties of Fresh Cold-stored Allografts for Osteochondral Defects at 1 Year

    PubMed Central

    Ranawat, Anil S.; Vidal, Armando F.; Chen, Chris T.; Zelken, Jonathan A.; Turner, A. Simon

    2008-01-01

    Little is known about the long-term properties of fresh cold-stored osteochondral allograft tissue. We hypothesized fresh cold-stored tissue would yield superior material properties in an in vivo ovine model compared to those using freeze-thawed acellular grafts. In addition, we speculated that a long storage time would yield less successful grafts. We created 10-mm defects in medial femoral condyles of 20 sheep. Defects were reconstructed with allograft plugs stored at 4°C for 1, 14, and 42 days; control specimens were freeze-thawed or defect-only. At 52 weeks, animals were euthanized and retrieved grafts were analyzed for cell viability, gross morphology, histologic grade, and biomechanical and biochemical analysis. Explanted cold-stored tissue had superior histologic scores over freeze-thawed and defect-only grafts. Specimens stored for 1 and 42 days had higher equilibrium moduli and proteoglycan content than freeze-thawed specimens. We observed no difference among any of the cold-stored specimens for chondrocyte viability, histology, equilibrium aggregate modulus, proteoglycan content, or hypotonic swelling. Reconstructing cartilage defects with cold-stored allograft resulted in superior histologic and biomechanical properties compared with acellular freeze-thawed specimens; however, storage time did not appear to be a critical factor in the success of the transplanted allograft. PMID:18528743

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

    NASA Technical Reports Server (NTRS)

    Gantz, E. E.

    1977-01-01

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

  18. [Variations of IR-spectra of three coating materials before and after spraying on urea fertilizer].

    PubMed

    Liu, Xing-bin; Chen, Li-jun; Wu, Zhi-jie; Zhang, Guang-na

    2009-09-01

    Coated fertilizer is a hot spot in the domain of fertilizer research. Related researches mainly focused on the action mechanisms of coating materials in controlling the nutrient release from coated fertilizers, but less information is available on the structural variation of the coating materials before and after spraying on fertilizers, which is the key to whether we can directly use coating materials to extrapolate its mechanisms in controlling coated fertilizers' nutrient release. With polylactic acid (PLA), poly (butynelenes succinate) (PBS), and polycarbonate (PC) as test materials, the variations of their IR spectra before and after spraying on urea fertilizer were determined, which was aimed to supply theoretical basis for further studying the action mechanisms of coating materials in controlling coated fertilizers nutrient release. The results showed that PLA and PC had less variation in their IR spectra before and after spraying on urea fertilizer, while PBS acted in reverse, suggesting that the former two coating materials could be directly used for studying the patterns of nutrient release from coated fertilizers. PMID:19950629

  19. Comparison of the Mechanical and Electrochemical Properties of WC-25Co Coatings Obtained by High Velocity Oxy-Fuel and Cold Gas Spraying

    NASA Astrophysics Data System (ADS)

    Couto, M.; Dosta, S.; Fernández, J.; Guilemany, J. M.

    2014-12-01

    Cold gas spray (CGS) coatings were previously produced by spraying WC-25Co cermet powders onto Al7075-T6 and low-carbon steel substrates. Unlike conventional flame spray techniques (e.g., high-velocity oxy-fuel; HVOF), no melting of the powder occurs; the particles are deformed and bond together after being sprayed by a supersonic jet of compressed gas, thereby building up several layers and forming a coating. WC-Co cermets are used in wear-resistant parts, because of their combination of mechanical, physical, and chemical properties. XRD tests were previously run on the initial powder and the coatings to determine possible phase changes during spraying. The bonding strength of the coatings was measured by adhesion tests. Here, WC-25Co coatings were also deposited on the same substrates by HVOF spraying. The wear resistance and fracture toughness of the coatings obtained previously by CGS and the HVOF coatings obtained here were studied. Their corrosion resistance was determined by electrochemical measurements. It was possible to achieve thick, dense, and hard CGS coatings on Al7075-T6 and low-carbon steel substrates, with better or the same mechanical and electrochemical properties as those of the HVOF coatings; making the former a highly competitive method for producing WC-25Co coatings.

  20. Normal modes in an overmoded circular waveguide coated with lossy material

    NASA Technical Reports Server (NTRS)

    Lee, C. S.; Lee, S. W.; Chuang, S. L.

    1985-01-01

    The normal modes in an overmoded waveguide coated with a lossy material are analyzed, particularly for their attenuation properties as a function of coating material, layer thickness, and frequency. When the coating material is not too lossy, the low-order modes are highly attenuated even with a thin layer of coating. This coated guide serves as a mode suppressor of the low-order modes, which can be particularly useful for reducing the radar cross section (RCS) of a cavity structure such as a jet inlet. When the coating material is very lossy, low-order modes fall into two distinct groups: highly and lowly attenuated modes. However, as a/lambda (a = radius of the cylinder; lambda = the free-space wavelength) increases, the separation between these two groups becomes less distinctive. The attenuation constants of most of the low-order modes become small, and decrease as a function of lambda sup 2/a sup 3.

  1. Study of mechanical properties and high temperature oxidation behavior of a novel cold-spray Ni-20Cr coating on boiler steels

    NASA Astrophysics Data System (ADS)

    Kaur, Narinder; Kumar, Manoj; Sharma, Sanjeev K.; Kim, Deuk Young; Kumar, S.; Chavan, N. M.; Joshi, S. V.; Singh, Narinder; Singh, Harpreet

    2015-02-01

    In the current investigation, high temperature oxidation behavior of a novel cold-spray Ni-20Cr nanostructured coating was studied. The nanocrystalline Ni-20Cr powder was synthesized by the investigators using ball milling, which was deposited on T22 and SA 516 steels by cold spraying. The crystallite size based upon Scherrer's formula for the developed coatings was found to be in nano-range for both the substrates. The accelerated oxidation testing was performed in a laboratory tube furnace at a temperature 900 °C under thermal cyclic conditions. Each cycle comprised heating for one hour at 900 °C followed by cooling for 20 min in ambient air. The kinetics of oxidation was established using weight change measurements for the bare and the coated steels. The oxidation products were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS) and X-ray mapping techniques. It was found from the results that the coating was successful in reducing the weight gain of SA213-T22 and SA 516-Grade 70 steel by 71% and 94%, respectively. This may be attributed to relatively denser structure, lower porosity and lower oxide content of the coating. Moreover, the developed nano-structured Ni-20Cr powder coating was found to perform better than its counterpart micron-sized Ni-20Cr powder coating, in terms of offering higher oxidation resistance and hardness.

  2. Evaluation of magnetostrictive composite coated fabric as a fragment barrier material

    NASA Astrophysics Data System (ADS)

    Son, Kwon Joong; Fahrenthold, Eric P.

    2012-10-01

    Over the last decade a surge in fragment barrier research has led to investigation of numerous materials and material augmentations in the attempt to improve the ballistic performance of systems designed to protect personnel, vehicles or infrastructure from impact and blast loads. One widely studied material augmentation approach is the use of coatings, often polymers, to enhance the performance of protection systems constructed from metal, concrete, composite and fabric materials. In recent research the authors have conducted the first experimental study of the ballistic performance of fabrics coated with a magnetically responsive polymer. Zero field impact experiments on coated fabric targets showed a 61% increase in impact energy dissipation, although the coated targets were not competitive with neat fabrics on a protection per unit mass basis. Under an applied field of 110 kA m-1, the ballistic performance of the coated fabric was reduced. The reduction in performance may be attributed to a reduction in material damping and an increase in material modulus for the magnetostrictive component of the coating. Analysis of the coated fabric response to magnetic preloads suggests that coating tensile stresses and coating-fabric interface stresses induced by the applied field may also adversely affect ballistic performance.

  3. Single-drop impact damage prediction for low density, coated ceramic materials. [rain erosion

    NASA Technical Reports Server (NTRS)

    Mustelier, D.

    1984-01-01

    A technique utilizing finite element analysis, liquid impact kinematics, and momentum theory is described and compared to single-drop impact test data performed on various configurations of coated ceramic material. The method correlates well with test data and is useful in predicting the single-drop impact damage velocity threshold for low-density, coated ceramic materials.

  4. 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.

  5. Thermal analysis of coatings and substrate materials during a disruption in fusion reactors

    SciTech Connect

    Hassanein, A.

    1993-06-01

    In a tokamak fusion reactor, the frequency of occurrence and the severity of a plasma disruption event will determine the lifetime of the plasma facing components. Disruptions are plasma instabilities which result in rapid loss of confinement and termination of plasma current Intense energy fluxes to components like the rust wall and the divertor plate are expected during the disruptions. This high energy deposition in short times may cause severe surface erosion of these components resulting from melting and vaporization. Coatings and tile materials are proposed to protect and maintain the integrity of the underneath, structural materials from both erosion losses as well as from high thermal stresses encountered during a disruption. The coating thickness should be large enough to withstand both erosion losses and to reduce the temperature rise in the substrate structural material. The coating thickness should be minimized to enhance the structural integrity, to reduce potential problems from radioactivity, and to minimize materials cost. Tile materials such as graphite and coating materials such as beryllium and tungsten on structural materials like copper, steel, and vanadium are analyzed and compared as potential diverter and first wall design options. The effect of the sprayed coating properties during the disruption is investigated. Porous sprayed material may be found to protect the structure better than condensed phase properties. The minimum coating thickness required to protect the structural material during disruption is discussed. The impact of self shielding effect by the eroded material oil the response of both the type/coating and the substrate is discussed.

  6. A Study of Deposition Coatings Formed by Electroformed Metallic Materials

    PubMed Central

    Shimura, Kojiro; Tobayama, Go; Togashi, Toshio

    2016-01-01

    Major joining methods of dental casting metal include brazing and laser welding. However, brazing cannot be applied for electroformed metals since heat treatment could affect the fit, and, therefore, laser welding is used for such metals. New methods of joining metals that do not impair the characteristics of electroformed metals should be developed. When new coating is performed on the surface of the base metal, surface treatment is usually performed before re-coating. The effect of surface treatment is clinically evaluated by peeling and flex tests. However, these testing methods are not ideal for deposition coating strength measurement of electroformed metals. There have been no studies on the deposition coating strength and methods to test electroformed metals. We developed a new deposition coating strength test for electroformed metals. The influence of the negative electrolytic method, which is one of the electrochemical surface treatments, on the strength of the deposition coating of electroformed metals was investigated, and the following conclusions were drawn: 1. This process makes it possible to remove residual deposits on the electrodeposited metal surface layer. 2. Cathode electrolysis is a simple and safe method that is capable of improving the surface treatment by adjustments to the current supply method and current intensity. 3. Electrochemical treatment can improve the deposition coating strength compared to the physical or chemical treatment methods. 4. Electro-deposition coating is an innovative technique for the deposition coating of electroformed metal. PMID:27326757

  7. A Study of Deposition Coatings Formed by Electroformed Metallic Materials.

    PubMed

    Hayashi, Shoji; Sugiyama, Shuta; Shimura, Kojiro; Tobayama, Go; Togashi, Toshio

    2016-01-01

    Major joining methods of dental casting metal include brazing and laser welding. However, brazing cannot be applied for electroformed metals since heat treatment could affect the fit, and, therefore, laser welding is used for such metals. New methods of joining metals that do not impair the characteristics of electroformed metals should be developed. When new coating is performed on the surface of the base metal, surface treatment is usually performed before re-coating. The effect of surface treatment is clinically evaluated by peeling and flex tests. However, these testing methods are not ideal for deposition coating strength measurement of electroformed metals. There have been no studies on the deposition coating strength and methods to test electroformed metals. We developed a new deposition coating strength test for electroformed metals. The influence of the negative electrolytic method, which is one of the electrochemical surface treatments, on the strength of the deposition coating of electroformed metals was investigated, and the following conclusions were drawn: 1. This process makes it possible to remove residual deposits on the electrodeposited metal surface layer. 2. Cathode electrolysis is a simple and safe method that is capable of improving the surface treatment by adjustments to the current supply method and current intensity. 3. Electrochemical treatment can improve the deposition coating strength compared to the physical or chemical treatment methods. 4. Electro-deposition coating is an innovative technique for the deposition coating of electroformed metal. PMID:27326757

  8. Effects of Tooth Coating Material and Finishing Agent on Bleached Enamel Surfaces by KTP Laser

    PubMed Central

    Kameda, Ayumi; Masuda, Yoshiko Murakami; Teruo, Toko; Yamada, Yoshishige; Kimura, Yuichi; Tamaki, Yukimichi; Miyazaki, Takashi

    2013-01-01

    Objective: The purpose of this study was to evaluate the effect of tooth coating material and finishing agent on bleached enamel surfaces after using KTP laser with 27% hydrogen peroxide. Background data: There have been few reports on the effects of tooth coating materials and finishing agents after bleaching. Methods: After 40 crowns of human extracted maxillary incisors were bleached by KTP laser, bleached enamels were finished with fluoride only or both of fluoride and nano-hydroxyapatite as a finishing agent. After application(s) of fluoride and/or finishing agent, the enamel surfaces were divided into 2 groups, which were covered with the coating material or without coating material. After application of coating materials, all specimens were kept for 2 weeks at 37°C of 100% humidity. After removing the coating material, color changing was measured and enamel surfaces were examined by scanning electron microscopy (SEM). Results: SEM observation of enamel surfaces treated the fluoride gel, finishing agent and coating material showed the most flattered surface compared to other groups. By measuring the color changing, few color changing was observed on the enamel surfaces treated the fluoride gel, finishing agents and coating material. Conclusion: These results suggested that applications of fluoride gel, finishing agent and coating material made the enamel-surfaces flattered and kept effects of bleaching, could prevent the re-coloration. After applications of fluoride gel and finishing agent, covering the bleached-enamel surfaces with the coating material enhanced the keeping whiteness. It would give the patients satisfaction of whiteness. PMID:24155557

  9. Effect of Surface Preparation on the Microstructure, Adhesion, and Tensile Properties of Cold-Sprayed Aluminum Coatings on AA2024 Substrates

    NASA Astrophysics Data System (ADS)

    Sharma, M. M.; Eden, T. J.; Golesich, B. T.

    2015-02-01

    Commercially pure aluminum coatings (CP-Al) were applied to AA 2024-T351 substrates utilizing the cold spray process using different surface preparation methods and carrier gases; the resulting microstructures and mechanical properties were investigated. Substrate preparation methods were examined to understand the effect of substrate roughness on coating properties, to minimize embedded grit, and to identify the surface preparation method that yielded the best combination of coating properties. Three substrate roughing preparations, glass bead, SiC grit, and alumina grit blast, were examined while utilizing both helium and nitrogen as carrier gases in the cold spray process. Coatings that were oxide free, possessing densities greater than 99% were achieved, with the mean coating porosity ranging 0.1-0.5%. The highest mean adhesion strength was 42 MPa for the nitrogen gas and 20 MPa for the helium gas, both using glass bead surface preparation. For the nitrogen process gas samples, the surface preparation methods that produced high pull strengths correlated to bend test specimens that showed no signs of cracking on surfaces or edges. The overall best combination of mechanical property results was achieved with coatings prepared by glass bead surface roughening using nitrogen as a carrier gas.

  10. Evaluation of Coatings and Materials for Future Radiators

    NASA Technical Reports Server (NTRS)

    Tuan, George C.; Westheimer, David T.; Birur, Gajanana C.; Beach, Duane E.; Jaworske, Donald A.; Peters, Wanda C.; Triolo, Jack J.

    2006-01-01

    Radiators are used to reject energy from space vehicles through radiant heat transfer. They are typically the largest component in a vehicle's thermal control system and can have a large impact on the vehicle design and operation. NASA s current vision for exploration dictates that radiators for a Crew Exploration Vehicle (CEV), a Lunar Surface Access Module (LSAM), and a lunar base will need to be developed. These applications present new challenges when compared to previous radiators on the Space Shuttle and International Space Station (ISS). In addition, many technological advances have been made that could positively impact future radiator design. This paper outlines new requirements for future radiators and documents a trade study performed to select the some promising technologies for further evaluation. The technologies include K1100 based carbon composites for the radiator surface as well as Optical Solar Reflectors (OSRs), a lithium based white paint, and electrochromic thin films for optical coatings. Coupons were made using these materials and tests were performed to characterize their performance. Testing included evaluating structural and thermal properties of the carbon composites, thermal cycling, launch pad weather simulation, and exposure to solar wind, and Ultraviolet (UV) radiation.

  11. Effect of antifungal hydroxypropyl methylcellulose-lipid edible composite coatings on Penicillium decay development and postharvest quality of cold-stored "Ortanique" mandarins.

    PubMed

    Valencia-Chamorro, Silvia A; Pérez-Gago, María B; Del Río, Miguel A; Palou, Lluís

    2010-10-01

    Edible composite coatings based on hydroxypropyl methylcellulose (HPMC), hydrophobic components (beeswax and shellac), and food preservatives with antifungal properties were evaluated on "Ortanique" mandarins during long-term cold storage. Selected food preservatives included potassium sorbate (PS), sodium benzoate (SB), sodium propionate (SP), and their mixtures. Intact mandarins or mandarins artificially inoculated with the pathogens Penicillium digitatum and Penicillium italicum, the causal agents of citrus postharvest green (GM) and blue (BM) molds, respectively, were coated and stored up to 8 wk at 5 °C + 1 wk of shelf-life at 20 °C. HPMC-lipid coatings containing food preservatives controlled better GM than BM on Ortanique mandarins. SB- and SB + SP-based coatings reduced the incidence of GM by about 35% after 4 wk at 5 °C. Among all coatings, only the SB-based coating reduced the incidence of GM (about 16%) after 6 wk at 5 °C. All coatings significantly reduced disease severity of both GM and BM after 6 wk at 5 °C. Analytical and sensory fruit quality was evaluated on intact mandarins. All coatings, especially the SB + SP-based coatings, were effective to control weight loss and maintain the firmness of coated mandarins. Internal gas concentration, juice ethanol and acetaldehyde content, sensory flavor, off-flavor, and fruit appearance were not adversely affected by the application of the antifungal coatings. Further studies should focus on the modification of some physical characteristics of the coatings to improve the gloss and visual aspect of treated mandarins. PMID:21535515

  12. Carbon coating of simulated nuclear-waste material

    SciTech Connect

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

    1982-03-01

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

  13. Improve the performance of coated cemented hip stem through the advanced composite materials.

    PubMed

    Hedia, H S; Fouda, N

    2015-01-01

    Design of hip joint implant using functionally graded material (FGM) (advanced composite material) has been used before through few researches. It gives great results regarding the stress distribution along the implant and bone interfaces. However, coating of orthopaedic implants has been widely investigated through many researches. The effect of using advanced composite stem material, which mean by functionally graded stem material, in the total hip replacement coated with the most common coated materials has not been studied yet. Therefore, this study investigates the effect of utilizing these two concepts together; FGM and coating, in designing new stem material. It is concluded that the optimal FGM cemented stem is consisting from titanium at the upper stem layers graded to collagen at a lower stem layers. This optimal graded stem coated with hydroxyapatite found to reduce stress shielding by 57% compared to homogenous titanium stem coated with hydroxyapatite. However, the optimal functionally graded stem coated with collagen reduced the stress shielding by 51% compared to homogenous titanium stem coated with collagen. PMID:26407117

  14. Efficient anti-corrosive coating of cold-rolled steel in a seawater environment using an oil-based graphene oxide ink

    NASA Astrophysics Data System (ADS)

    Singhbabu, Y. N.; Sivakumar, B.; Singh, J. K.; Bapari, H.; Pramanick, A. K.; Sahu, Ranjan K.

    2015-04-01

    We report the production of an efficient anti-corrosive coating of cold-rolled (CR) steel in a seawater environment (~3.5 wt% NaCl aqueous solution) using an oil-based graphene oxide ink. The graphene oxide was produced by heating Aeschynomene aspera plant as a carbon source at 1600 °C in an argon atmosphere. The ink was prepared by cup-milling the mixture of graphene oxide and sunflower oil for 10 min. The coating of ink on the CR steel was made using the dip-coating method, followed by curing at 350 °C for 10 min in air atmosphere. The results of the potentiodynamic polarization show that the corrosion rate of bare CR steel decreases nearly 10 000-fold by the ink coating. Furthermore, the salt spray test results show that the red rusting in the ink-coated CR steel is initiated after 100 h, in contrast to 24 h and 6 h in the case of oil-coated and bare CR steel, respectively. The significant decrease in the corrosion rate by the ink-coating is discussed based on the impermeability of graphene oxide to the corrosive ions.We report the production of an efficient anti-corrosive coating of cold-rolled (CR) steel in a seawater environment (~3.5 wt% NaCl aqueous solution) using an oil-based graphene oxide ink. The graphene oxide was produced by heating Aeschynomene aspera plant as a carbon source at 1600 °C in an argon atmosphere. The ink was prepared by cup-milling the mixture of graphene oxide and sunflower oil for 10 min. The coating of ink on the CR steel was made using the dip-coating method, followed by curing at 350 °C for 10 min in air atmosphere. The results of the potentiodynamic polarization show that the corrosion rate of bare CR steel decreases nearly 10 000-fold by the ink coating. Furthermore, the salt spray test results show that the red rusting in the ink-coated CR steel is initiated after 100 h, in contrast to 24 h and 6 h in the case of oil-coated and bare CR steel, respectively. The significant decrease in the corrosion rate by the ink-coating is

  15. In vivo and in vitro investigations of a nanostructured coating material – a preclinical study

    PubMed Central

    Adam, Martin; Ganz, Cornelia; Xu, Weiguo; Sarajian, Hamid-Reza; Götz, Werner; Gerber, Thomas

    2014-01-01

    Immediate loading of dental implants is only possible if a firm bone-implant anchorage at early stages is developed. This implies early and high bone apposition onto the implant surface. A nanostructured coating material based on an osseoinductive bone grafting is investigated in relation to the osseointegration at early stages. The goal is to transmit the structure (silica matrix with embedded hydroxyapatite) and the properties of the bone grafting into a coating material. The bone grafting substitute offers an osseoinductive potential caused by an exchange of the silica matrix in vivo accompanied by vascularization. X-ray diffraction and transmission electron microscopy analysis show that the coating material consists of a high porous silica matrix with embedded nanocrystalline hydroxyapatite with the same morphology as human hydroxyapatite. An in vitro investigation shows the early interaction between coating and human blood. Energy-dispersive X-ray analysis showed that the silica matrix was replaced by an organic matrix within a few minutes. Uncoated and coated titanium implants were inserted into the femora of New Zealand White rabbits. The bone-to-implant contact (BIC) was measured after 2, 4, and 6 weeks. The BIC of the coated implants was increased significantly at 2 and 4 weeks. After 6 weeks, the BIC was decreased to the level of the control group. A histological analysis revealed high bone apposition on the coated implant surface after 2 and 4 weeks. Osteoblastic and osteoclastic activities on the coating material indicated that the coating participates in the bone-remodeling process. The nanostructure of the coating material led to an exchange of the silica matrix by an autologous, organic matrix without delamination of the coating. This is the key issue in understanding initial bone formation on a coated surface. PMID:24627631

  16. Durable polymer-aerogel based superhydrophobic coatings, a composite material

    DOEpatents

    Kissel, David J; Brinker, Charles Jeffrey

    2014-03-04

    Provided are polymer-aerogel composite coatings, devices and articles including polymer-aerogel composite coatings, and methods for preparing the polymer-aerogel composite. The exemplary article can include a surface, wherein the surface includes at least one region and a polymer-aerogel composite coating disposed over the at least one region, wherein the polymer-aerogel composite coating has a water contact angle of at least about 140.degree. and a contact angle hysteresis of less than about 1.degree.. The polymer-aerogel composite coating can include a polymer and an ultra high water content catalyzed polysilicate aerogel, the polysilicate aerogel including a three dimensional network of silica particles having surface functional groups derivatized with a silylating agent and a plurality of pores.

  17. Durable polymer-aerogel based superhydrophobic coatings: a composite material

    DOEpatents

    Kissel, David J.; Brinker, Charles Jeffrey

    2016-02-02

    Provided are polymer-aerogel composite coatings, devices and articles including polymer-aerogel composite coatings, and methods for preparing the polymer-aerogel composite. The exemplary article can include a surface, wherein the surface includes at least one region and a polymer-aerogel composite coating disposed over the at least one region, wherein the polymer-aerogel composite coating has a water contact angle of at least about 140.degree. and a contact angle hysteresis of less than about 1.degree.. The polymer-aerogel composite coating can include a polymer and an ultra high water content catalyzed polysilicate aerogel, the polysilicate aerogel including a three dimensional network of silica particles having surface functional groups derivatized with a silylating agent and a plurality of pores.

  18. The folded conformation of phage P22 coat protein is affected by amino acid substitutions that lead to a cold-sensitive phenotype.

    PubMed

    Fong, D G; Doyle, S M; Teschke, C M

    1997-04-01

    Three cold-sensitive mutants in phage P22 coat protein have been characterized to determine the effects of the amino acid substitutions that cause cold sensitivity on the folding pathway and the conformation of refolded coat protein. Here we find that the three cold-sensitive mutants which have the threonine residue at position 10 changed to isoleucine (T10I), the arginine residue at position 101 changed to cysteine (R101C), or the asparagine residue at position 414 changed to serine (N414S) were capable of folding from a denatured state into a soluble monomeric species, but in each case, the folded conformation was altered. Changes in the kinetics of folding were observed by both tryptophan and bisANS fluorescence. In contrast to the temperature-sensitive for folding coat protein mutants which can be rescued at nonpermissive temperatures in vivo by the overproduction of molecular chaperones GroEL and GroES [Gordon, C. L., Sather, S. K., Casjens, S., & King, J. (1994) J. Biol. Chem. 269, 27941-27951], the folding defects associated with the cold-sensitive amino acid substitutions were not recognized by GroEL and GroES. PMID:9092827

  19. Contamination control in hybrid microelectronic modules. Part 2: Selection and evaluation of coating materials

    NASA Technical Reports Server (NTRS)

    Himmel, R. P.

    1975-01-01

    The selection, test, and evaluation of organic coating materials for contamination control in hybrid circuits is reported. The coatings were evaluated to determine their suitability for use as a conformal coating over the hybrid microcircuit (including chips and wire bonds) inside a hermetically sealed package. Evaluations included ease of coating application and repair and effect on thin film and thick film resistors, beam leads, wire bonds, transistor chips, and capacitor chips. The coatings were also tested for such properties as insulation resistance, voltage breakdown strength, and capability of immobilizing loose particles inside the packages. The selected coatings were found to be electrically, mechanically, and chemically compatible with all components and materials normally used in hybrid microcircuits.

  20. Flexural Strength of Cold and Heat Cure Acrylic Resins Reinforced with Different Materials

    PubMed Central

    Heidari, Bijan; Firouz, Farnaz; Izadi, Alireza; Ahmadvand, Shahbaz

    2015-01-01

    Objectives: Heat-polymerized acrylic resin has been the most commonly used denture base material for over 60 years. However, the mechanical strength of acrylic resin is not adequate for long-term clinical performance of dentures. Consequently, fracture is a common clinical occurrence, which often develops in the midline of the denture base. This study aimed to evaluate the efficacy of cold-cure and heat-cure acrylic resins, reinforced with glass fibers, polyethylene fibers, and metal wire for denture base repair. Materials and Methods: Ninety specimens were prepared and allocated to nine groups. Ten specimens were considered as controls, and 80 were divided into 8 experimental groups. In the experimental groups, the specimens were sectioned into two halves from the middle, and were then divided into two main groups: one group was repaired with heat cure acrylic resin, and the other with cold cure acrylic resin. Each group was divided into 4 subgroups: unreinforced, reinforced with glass fibers, polyethylene fibers, and metal wire. All specimens were subjected to a 3-point bending test, and the flexural strength was calculated. Results: The group repaired with heat cure acrylic resin and reinforced with glass fiber showed the highest flexural strength; however, the group repaired with cold cure acrylic resin and reinforced with polyethylene fibers had the lowest flexural strength. There was no significant difference between the groups repaired with heat cure and cold cure acrylic resins without reinforcement. Conclusion: Repairing denture base with heat cure acrylic resin, reinforced with glass fibers increases the flexural strength of denture base. PMID:26877726

  1. Coating processes for increasing the moisture resistance of polyurethane baffle material

    NASA Technical Reports Server (NTRS)

    Bilow, N.; Sawko, P.

    1974-01-01

    An investigation was conducted with the objective to improve the hydrolytic stability of reticulated polyurethane baffle material. This material is used in fuel tanks of aircraft and ground vehicles. The most commonly used foam of this type is hydrolytically unstable. Potential moisture barrier coatings which were evaluated include Parylene, epoxy-polysulfide, polyether based polyurethanes, polysulfides, polyolefin rubbers, and several other materials. Parylene coatings of at least 0.2 mil were found to provide the greatest improvement in hydrolytic stability.

  2. FTIR characterization of heparinizable polymer-coated materials for application in biomedicine

    NASA Astrophysics Data System (ADS)

    Barbucci, Rolando; Magnani, Agnese

    1992-03-01

    Fourier Transform Attenuated Total Reflection Infrared Spectroscopy (ATR/FTIR) was used for surface characterization of some commercial materials used in the biomedical field [polyurethane (PU), plasticized polyvinylchloride (PVC), glass, polytetrafluoroethylene (Goretex) and polyethyleneterephthalate (Dacron)] coated with a well-characterized heparin-complexing biomaterial (PUPA) based on polyurethane and poly(amido-amine) components. In particular, difference spectroscopy was used to analyze the coating-substrate interaction to which the material stability is related, and the heparin-material surface binding.

  3. Ultrasonic Detection of Delamination and Material Characterization of Thermal Barrier Coatings

    NASA Astrophysics Data System (ADS)

    Chen, Hung-Liang Roger; Zhang, Binwei; Alvin, Mary Anne; Lin, Yun

    2012-12-01

    This article describes ultrasonic nondestructive evaluation (NDE) to detect the changes of material properties and provide early warning of delamination in thermal barrier coating (TBC) systems. NDE tests were performed on single-crystal René N5 superalloy coupons that were coated with a commercially available MCrAlY bond coat and an air plasma sprayed 7% yttria-stabilized zirconia (YSZ) top coat deposited by Air Plasma Spray method, as well as Haynes 230 superalloy coupons coated with MCrA1Y bond coat, and an electron beam physical vapor deposit of 7% YSZ top coat. The TBC coupons were subjected to either cyclic or isothermal exposure for various lengths of time at temperatures ranging from 900 to 1100 °C. The ultrasonic measurements performed on the coupons had provided an early warning of delamination along the top coat/TGO interface before exposure time, when delamination occurred. The material's property (Young's modulus) of the top coat was estimated using the measured wave speeds. Finite element analysis (FEA) of the ultrasonic wave propagation was conducted on a simplified TBC system to verify experimental observations. The technique developed was also demonstrated on an as-manufactured turbine blade to estimate normalized top coat thickness measurements.

  4. Ultrasonic Detection of Delamination and Material Characterization of Thermal Barrier Coatings

    SciTech Connect

    Chen, Hung-Liang Roger; Zhang, Binwei; Alvin, Mary Anne; Lin, Yun

    2012-12-01

    This article describes ultrasonic nondestructive evaluation (NDE) to detect the changes of material properties and provide early warning of delamination in thermal barrier coating (TBC) systems. NDE tests were performed on single-crystal René N5 superalloy coupons that were coated with a commercially available MCrAlY bond coat and an air plasma sprayed 7% yttria-stabilized zirconia (YSZ) top coat deposited by Air Plasma Spray method, as well as Haynes 230 superalloy coupons coated with MCrA1Y bond coat, and an electron beam physical vapor deposit of 7% YSZ top coat. The TBC coupons were subjected to either cyclic or isothermal exposure for various lengths of time at temperatures ranging from 900 to 1100 °C. The ultrasonic measurements performed on the coupons had provided an early warning of delamination along the top coat/TGO interface before exposure time, when delamination occurred. The material's property (Young’s modulus) of the top coat was estimated using the measured wave speeds. Finite element analysis (FEA) of the ultrasonic wave propagation was conducted on a simplified TBC system to verify experimental observations. The technique developed was also demonstrated on an as-manufactured turbine blade to estimate normalized top coat thickness measurements.

  5. Effects of coating material on the fabrication accuracy of focused ion beam machining of insulators

    NASA Astrophysics Data System (ADS)

    Joe, Hang-Eun; Park, Jae-Hyeong; Kim, Seong Hyeon; Kim, Gyuho; Jun, Martin B. G.; Min, Byung-Kwon

    2015-09-01

    Focused ion beam (FIB) machining of insulators is a crucial process in the rapid prototyping of nanodevices for optical applications. A conductive material is generally coated on the insulator prior to FIB machining to achieve high fabrication accuracy. In this paper, we report on the effects on machining accuracy of four coating materials: Pt, Ni, Ag, and Co. The dimensional accuracy at channel sidewalls was improved by selecting a coating material that induces charge-carrier generation in a small range. The geometric and electrical characteristics of the FIB-machined surfaces were evaluated to elucidate the association between the fabrication accuracy and the range of charge-carrier distribution.

  6. Materials for damping the PTC-induced thermal fluctuations of the cold-head

    NASA Astrophysics Data System (ADS)

    Catarino, I.; Martins, D.; Sudiwala, R.

    2015-12-01

    The cold head on mechanical Pulse Tube Cryocoolers (PTCs) is subject to substantially less mechanical vibration and electromagnetic interference compared to that typically found in Gifford MacMahon coolers. However, thermal fluctuations at the PTC frequency are still present at the cold-head, typically at a level of 200 mK peak-to-peak at 1.4 Hz for a Cryomech Model PT405 cooler running at 4 K. It is highly desirable to damp out these fluctuations if PTCs are to be used successfully for running systems sensitive to such thermal fluctuations, for example, bolometeric detectors. We report here the characterization over the temperature range 2.5 K to 6 K of two materials, GOS (Gd2O2S) and GAP (GdAlO3), for use as low-pass thermal filters. These materials have antiferromagnetic transitions at around 4 K giving rise to an enhanced heat capacity and have a high thermal conductance. These are two highly desirable properties for thermal dampers in this application. Those materials were fired as ceramic discs to be tested as thermal dumpers. Thermal filter assemblies with discs of diameter 75 mm and thickness 2.5 mm and 1.6 mm (GOS and GAP, respectively) mounted in a PTC show thermal attenuation levels of x0.12 (GOS) and x0.11 (GAP) at 0.01Hz with a clean-side temperature of 4 K; the PTC induced fluctuations at 1.48 Hz are damped completely to within the noise limits (0.2 mK) of the thermometers. Experimentally determined thermal conductance and heat capacity data are reported. For this system, with a PTC cold-head (dirty-side) temperature of 3.3 K, a clean-side power dissipation of up to 30 mW is realized before its temperature rises above 4.2 K.

  7. Efficient anti-corrosive coating of cold-rolled steel in a seawater environment using an oil-based graphene oxide ink.

    PubMed

    Singhbabu, Y N; Sivakumar, B; Singh, J K; Bapari, H; Pramanick, A K; Sahu, Ranjan K

    2015-05-01

    We report the production of an efficient anti-corrosive coating of cold-rolled (CR) steel in a seawater environment (∼3.5 wt% NaCl aqueous solution) using an oil-based graphene oxide ink. The graphene oxide was produced by heating Aeschynomene aspera plant as a carbon source at 1600 °C in an argon atmosphere. The ink was prepared by cup-milling the mixture of graphene oxide and sunflower oil for 10 min. The coating of ink on the CR steel was made using the dip-coating method, followed by curing at 350 °C for 10 min in air atmosphere. The results of the potentiodynamic polarization show that the corrosion rate of bare CR steel decreases nearly 10,000-fold by the ink coating. Furthermore, the salt spray test results show that the red rusting in the ink-coated CR steel is initiated after 100 h, in contrast to 24 h and 6 h in the case of oil-coated and bare CR steel, respectively. The significant decrease in the corrosion rate by the ink-coating is discussed based on the impermeability of graphene oxide to the corrosive ions. PMID:25869204

  8. Material Properties for the Simulation of Cold Pressing of Armstrong CP-Ti Powders

    SciTech Connect

    Sabau, Adrian S; Kiggans, Jim; Peter, William H; ERDMAN III, DONALD L; Wang, Yanli; Clark, Michael B

    2010-01-01

    A review of the mechanical property data needed for the process simulation of cold pressing was conducted. The material property data for the newly developed low-cost commercially pure titanium, CP-Ti, powders made by Armstrong process was presented. The following data was obtained from mechanical testing: Youngs modulus, bulk modulus, failure line for the plasticity model. The Youngs modulus and bulk modulus were obtained from the uniaxial compression tests of a cylinder. The failure line for the plasticity model was obtained from failure compression tests. Materials testing software was written to provide automatic test control and data acquisition during material testing, such as axial displacement, axial stress, radial strain, and failure stress.

  9. Laser ultrasound technique applied in material characterization of thermally sprayed nickel aluminum coatings

    NASA Astrophysics Data System (ADS)

    Yeh, C. H.; Yang, C. H.; Hsiao, W. T.; Su, C.-Y.

    2012-05-01

    Thermal spraying processing usually uses a nickel-aluminum alloy system as the major powder due to its strong adhesion to substrates. The contents of powder material and the processing parameters used in the spraying process cause material properties of coatings exhibiting a wide variation. This research aims at nondestructive characterization of thermal spraying coatings. A laser-generation/laser-detection laser ultrasound technique (LUT) is used for the measurements of dispersion spectra of surface waves propagating along the coated surfaces. Theoretical model for surface waves propagating along a multi-layered structure with coating and substrate is used to model the sprayed coatings. An inversion algorithm based on Shuffled Complex Evolution (SCE-UA) is used to extract mechanical properties from the measured dispersion spectra cooperating with theoretical model. Three coatings with different sprayed powders and powder processing are investigated. Results indicate that substantial linear scatterings are observed for the inverted properties due to the measured dispersion spectra with limited bandwidth inherited from the relatively high attenuations. The slope of linear scattering can be used to distinguish the coating properties. The ANiBNb sample with ball-milled coating has the best properties based on its highest velocity and least attenuation. This method is potentially useful to characterize the mechanical properties of thermally spraying coating in a nondestructive way.

  10. Impact of ALD Coating on Mn-rich Cathode Materials (Presentation)

    SciTech Connect

    Santhanagopalan, S.

    2013-06-01

    LG Chem Power Inc. (LGCPI) and NREL have collaborated to demonstrate the scalability of the atomic layer deposition (ALD) coating process over the last 6 months, and the benefits of ALD coatings for long-term cycling and calendar life are being quantified. The objectives of this work are two-fold: 1) to evaluate the scalability of the process to coat LGCPI cathodes with alumina using the ALD technique, and 2) to demonstrate improvements in rate capability and life of ALD-coated LGCPI electrodes. NREL received samples of baseline material to be coated from LGCPI. NREL carried out ALD coating of the samples with help from a subcontractor, ALD Nanosolutions. NREL fabricated cells from those samples for quick screening and feedback to ALD Nanosolutions. LGCPI is currently fabricating larger-format cells for further evaluation.