WorldWideScience

Sample records for high temperature coatings

  1. Development of High Temperature Solid Lubricant Coatings

    National Research Council Canada - National Science Library

    Bhattacharya, Rabi

    1999-01-01

    ... environment. To test this approach, UES and Cleveland State University have conducted experiments to form cesium oxythiotungstate, a high temperature lubricant, on Inconel 718 surface from composite coatings...

  2. High temperature solar selective coatings

    Science.gov (United States)

    Kennedy, Cheryl E

    2014-11-25

    Improved solar collectors (40) comprising glass tubing (42) attached to bellows (44) by airtight seals (56) enclose solar absorber tubes (50) inside an annular evacuated space (54. The exterior surfaces of the solar absorber tubes (50) are coated with improved solar selective coatings {48} which provide higher absorbance, lower emittance and resistance to atmospheric oxidation at elevated temperatures. The coatings are multilayered structures comprising solar absorbent layers (26) applied to the meta surface of the absorber tubes (50), typically stainless steel, topped with antireflective Savers (28) comprising at least two layers 30, 32) of refractory metal or metalloid oxides (such as titania and silica) with substantially differing indices of refraction in adjacent layers. Optionally, at least one layer of a noble metal such as platinum can be included between some of the layers. The absorbent layers cars include cermet materials comprising particles of metal compounds is a matrix, which can contain oxides of refractory metals or metalloids such as silicon. Reflective layers within the coating layers can comprise refractory metal silicides and related compounds characterized by the formulas TiSi. Ti.sub.3SiC.sub.2, TiAlSi, TiAN and similar compounds for Zr and Hf. The titania can be characterized by the formulas TiO.sub.2, Ti.sub.3O.sub.5. TiOx or TiO.sub.xN.sub.1-x with x 0 to 1. The silica can be at least one of SiO.sub.2, SiO.sub.2x or SiO.sub.2xN.sub.1-x with x=0 to 1.

  3. Corrosion Resistant Coatings for High Temperature Applications

    Energy Technology Data Exchange (ETDEWEB)

    Besman, T.M.; Cooley, K.M.; Haynes, J.A.; Lee, W.Y.; Vaubert, V.M.

    1998-12-01

    Efforts to increase efficiency of energy conversion devices have required their operation at ever higher temperatures. This will force the substitution of higher-temperature structural ceramics for lower temperature materials, largely metals. Yet, many of these ceramics will require protection from high temperature corrosion caused by combustion gases, atmospheric contaminants, or the operating medium. This paper discusses examples of the initial development of such coatings and materials for potential application in combustion, aluminum smelting, and other harsh environments.

  4. Multilayer ultra-high-temperature ceramic coatings

    Science.gov (United States)

    Loehman, Ronald E [Albuquerque, NM; Corral, Erica L [Tucson, AZ

    2012-03-20

    A coated carbon-carbon composite material with multiple ceramic layers to provide oxidation protection from ultra-high-temperatures, where if the carbon-carbon composite material is uninhibited with B.sub.4C particles, then the first layer on the composite material is selected from ZrB.sub.2 and HfB.sub.2, onto which is coated a layer of SiC coated and if the carbon-carbon composite material is inhibited with B.sub.4C particles, then protection can be achieved with a layer of SiC and a layer of either ZrB.sub.2 and HfB.sub.2 in any order.

  5. A study on heat resistance of high temperature resistant coating

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Liping; Wang, Xueying; Zhang, Qibin; Qin, Yanlong; Lin, Zhu [Research Institute of Engineering Technology of CNPC, Tianjin (China)

    2005-04-15

    A high temperature resistant coating has been developed, which is mainly for heavy oil production pipes deserved the serious corrosion. The coating has excellent physical and mechanical performance and corrosion resistance at room and high temperature. In order to simulate the underground working condition of heavy oil pipes,the heat resistance of the high temperature resistant coating has been studied. The development and a study on the heat resistance of the DHT high temperature resistance coating have been introduced in this paper

  6. A study on heat resistance of high temperature resistant coating

    International Nuclear Information System (INIS)

    Zhang, Liping; Wang, Xueying; Zhang, Qibin; Qin, Yanlong; Lin, Zhu

    2005-01-01

    A high temperature resistant coating has been developed, which is mainly for heavy oil production pipes deserved the serious corrosion. The coating has excellent physical and mechanical performance and corrosion resistance at room and high temperature. In order to simulate the underground working condition of heavy oil pipes,the heat resistance of the high temperature resistant coating has been studied. The development and a study on the heat resistance of the DHT high temperature resistance coating have been introduced in this paper

  7. High Temperature coatings based on β-NiAI

    Energy Technology Data Exchange (ETDEWEB)

    Severs, Kevin [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    High temperature alloys are reviewed, focusing on current superalloys and their coatings. The synthesis, characerization, and oxidation performance of a NiAl–TiB2 composite are explained. A novel coating process for Mo–Ni–Al alloys for improved oxidation performance is examined. The cyclic oxidation performance of coated and uncoated Mo–Ni–Al alloys is discussed.

  8. High-temperature polyimide coating for optical fibres

    Energy Technology Data Exchange (ETDEWEB)

    Semjonov, S L; Dianov, E M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Sapozhnikov, D A; Erin, D Yu; Zabegaeva, O N; Kushtavkina, I A; Vygodskii, Ya S [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow (Russian Federation); Nishchev, K N [N.P. Ogarev Mordovia State University, Saransk (Russian Federation)

    2015-04-30

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

  9. High emissivity coatings for high temperature application: Progress and prospect

    International Nuclear Information System (INIS)

    He Xiaodong; Li Yibin; Wang Lidong; Sun Yue; Zhang, Sam

    2009-01-01

    High emissivity coatings are widely used in many cases where heat transfers through electromagnetic radiation that arises due to the temperature of a body. Extensive theoretical and experimental efforts have been made to synthesize and investigate high emissivity coatings. The emissivity can be improved through various or combined mechanisms. The characterization of the emissivity is still a fully open problem. In this paper, we review the various mechanisms associated with the emissivity enhancement and emissivity characterization techniques. Based on these literature reviews, the prospect will be presented in the concluding remarks.

  10. Sealed glass coating of high temperature ceramic superconductors

    Science.gov (United States)

    Wu, Weite; Chu, Cha Y.; Goretta, Kenneth C.; Routbort, Jules L.

    1995-01-01

    A method and article of manufacture of a lead oxide based glass coating on a high temperature superconductor. The method includes preparing a dispersion of glass powders in a solution, applying the dispersion to the superconductor, drying the dispersion before applying another coating and heating the glass powder dispersion at temperatures below oxygen diffusion onset and above the glass melting point to form a continuous glass coating on the superconductor to establish compressive stresses which enhance the fracture strength of the superconductor.

  11. High-Temperature Coatings Offer Energy Savings

    Science.gov (United States)

    2012-01-01

    The U.S. X-Plane Program included the first-of-its-kind research in aerodynamics and astronautics with experimental vehicles, including the first aircraft to break the sound barrier; the first aircraft to fly in excess of 100,000, then 200,000, and then 300,000 feet; and the first aircraft to fly at three, four, five, and then six times the speed of sound. During the 1990s, NASA started developing a new thermal protection material to test on the X-33 and X-34 supersonic aircraft. The X-33 was intended to demonstrate the technologies needed for a new reusable launch vehicle and was projected to reach an altitude of approximately 50 miles and speeds of more than Mach 11. The X-34, a small, reusable technology demonstrator for a launch vehicle, was intended to reach an altitude of 250,000 feet and fly at speeds of Mach 8. As a result of its research and development efforts, NASA s Ames Research Center invented the Protective Ceramic Coating Material (PCCM). Applied to a surface, the thin, lightweight coating could protect the material underneath from extreme temperatures. The capability of the technology came from its emissivity, which radiated heat away from the surface it covered, thereby decreasing the amount of heat transferred to the underlying material. PCCM not only increased the capability of materials to withstand higher temperatures, it also exhibited impressive thermal shock, vibration, and acoustic performance. In addition, it proved to be resistant to abrasion and mechanical damage and was also environmentally safe, due to it being water-based and containing no solvents. Even though funding for the X-33 and X-34 ended in 2001, PCCM continued on a path of innovation.

  12. Materials Science of High-Temperature Superconducting Coated Conductor Materials

    National Research Council Canada - National Science Library

    Beasley, M. R

    2007-01-01

    This program was broadly focused on the materials science of high temperature superconducting coated conductors, which are of potential interest for application in electric power systems of interest to the Air Force...

  13. Materials and coatings to resist high temperature oxidation and corrosion

    International Nuclear Information System (INIS)

    1977-01-01

    Object of the given papers are the oxidation and corrosion behaviour of several materials (such as stainless steels, iron-, or nickel-, or cobalt-base alloys, Si-based ceramics) used at high temperatures and various investigations on high-temperature protective coatings. (IHoe) [de

  14. High temperature oxidation of slurry coated interconnect alloys

    DEFF Research Database (Denmark)

    Persson, Åsa Helen

    with this interaction mechanism mainly give a geometrical protection against oxidation by blocking oxygen access at the surface of the oxide scale. The protecting effect is gradually reduced as the oxide scale grows thicker than the diameter of the coating particles. Interaction mechanism B entails a chemical reaction...... scale. The incorporated coating particles create a geometrical protection against oxidation that should not loose their effect after the oxide scale has grown thicker than the diameter of the coating particles. The two single layer coatings consisting of (La0.85Sr0.15)MnO3 + 10% excess Mn, LSM, and (La0......In this project, high temperature oxidation experiments of slurry coated ferritic alloys in atmospheres similar to the atmosphere found at the cathode in an SOFC were conducted. From the observations possible interaction mechanisms between the slurry coatings and the growing oxide scale...

  15. Evolution of sputtered tungsten coatings at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Stelmakh, Veronika; Rinnerbauer, Veronika; Joannopoulos, John D.; Soljačić, Marin; Celanovic, Ivan; Senkevich, Jay J. [Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Tucker, Charles; Ives, Thomas; Shrader, Ronney [Materion Corporation, Buellton, California 93427 (United States)

    2013-11-15

    Sputtered tungsten (W) coatings were investigated as potential high temperature nanophotonic material to replace bulk refractory metal substrates. Of particular interest are materials and coatings for thermophotovoltaic high-temperature energy conversion applications. For such applications, high reflectance of the substrate in the infrared wavelength range is critical in order to reduce losses due to waste heat. Therefore, the reflectance of the sputtered W coatings was characterized and compared at different temperatures. In addition, the microstructural evolution of sputtered W coatings (1 and 5 μm thick) was investigated as a function of anneal temperature from room temperature to 1000 °C. Using in situ x-ray diffraction analysis, the microstrain in the two samples was quantified, ranging from 0.33% to 0.18% for the 1 μm sample and 0.26% to 0.20% for the 5 μm sample, decreasing as the temperature increased. The grain growth could not be as clearly quantified due to the dominating presence of microstrain in both samples but was in the order of 20 to 80 nm for the 1 μm sample and 50 to 100 nm for the 5 μm sample, as deposited. Finally, the 5 μm thick layer was found to be rougher than the 1 μm thick layer, with a lower reflectance at all wavelengths. However, after annealing the 5 μm sample at 900 °C for 1 h, its reflectance exceeded that of the 1 μm sample and approached that of bulk W found in literature. Overall, the results of this study suggest that thick coatings are a promising alternative to bulk substrates as a low cost, easily integrated platform for nanostructured devices for high-temperature applications, if the problem of delamination at high temperature can be overcome.

  16. Protective coatings for high temperature alloys state of technology

    International Nuclear Information System (INIS)

    Goward, G.W.

    1976-01-01

    Coatings used on nickel- and cobalt-base superalloy blades and vanes in gas turbine engines typify the state of coating technology for high temperature alloys. Coatings formed by interdiffusion of aluminum with the alloys to form layers consisting mainly of intermetallic compounds, such as NiAl and CoAl, were the first systems used for protection of gas turbine airfoils. The protectivity of these systems is derived from the formation of protective alumina scales. In a general way, coating degradation occurs by cyclic oxidation, molten salt hot corrosion and, at higher temperatures, interdiffusion with the substrate. Thermal fatigue properties are governed by the brittle-ductile transition behavior of the intermetallic compounds NiAl and CoAl. Both positive and negative effects occur, depending on the shapes of thermal strain-temperature curves for particular applications. Significant increases in hot corrosion and oxidation resistance have been obtained by the incorporation of noble metals, such as platinum, in aluminide coatings. The so-called MCrAlY overlay coatings, based on nickel, cobalt, iron and combinations thereof with chromium, aluminum and yttrium can be formulated over a wide range of compositions nominally independent of those of substrate alloys. Improved oxidation resistance and, in part, hot corrosion resistance is derived from yttrium which enhances protective oxide adherence. Mechanical properties, principally ductility, and therefore thermal fatigue resistance, can be adjusted to the requirements of specific applications. Incremental improvements in performance of the MCrAlY coatings are expected as research programs define degradation mechanisms in greater detail and more complex compositions are devised. More basic evaluations of mixed metal-ceramic insulative coatings have been initiated to determine if these systems are capable of effecting further increases in airfoil durability

  17. Thermal Protective Coating for High Temperature Polymer Composites

    Science.gov (United States)

    Barron, Andrew R.

    1999-01-01

    The central theme of this research is the application of carboxylate-alumoxane nanoparticles as precursors to thermally protective coatings for high temperature polymer composites. In addition, we will investigate the application of carboxylate-alumoxane nanoparticle as a component to polymer composites. The objective of this research was the high temperature protection of polymer composites via novel chemistry. The significance of this research is the development of a low cost and highly flexible synthetic methodology, with a compatible processing technique, for the fabrication of high temperature polymer composites. We proposed to accomplish this broad goal through the use of a class of ceramic precursor material, alumoxanes. Alumoxanes are nano-particles with a boehmite-like structure and an organic periphery. The technical goals of this program are to prepare and evaluate water soluble carboxylate-alumoxane for the preparation of ceramic coatings on polymer substrates. Our proposed approach is attractive since proof of concept has been demonstrated under the NRA 96-LeRC-1 Technology for Advanced High Temperature Gas Turbine Engines, HITEMP Program. For example, carbon and Kevlar(tm) fibers and matting have been successfully coated with ceramic thermally protective layers.

  18. Efficient dual layer interconnect coating for high temperature electrochemical devices

    DEFF Research Database (Denmark)

    Palcut, Marián; Mikkelsen, Lars; Neufeld, Kai

    2012-01-01

    Effects of novel dual layer coatings Co3O4/La0.85Sr0.15MnO3−δ on high temperature oxidation behaviour of candidate steels for interconnects are studied at 1123 K in flowing simulated ambient air (air + 1% H2O) and oxygen. Four alloys are investigated: Crofer 22 APU, Crofer 22 H, E-Brite and AL 29...... that the oxidation reaction is limited by outward Cr3+ diffusion in the chromia scale. The coating effectively reduces the oxidation rate. Reactions and cation inter-diffusion between the coating and the oxide scale are observed. Long term effects of these interactions are discussed and practical implications...

  19. High temperature oxidation behavior of SiC coating in TRISO coated particles

    International Nuclear Information System (INIS)

    Liu, Rongzheng; Liu, Bing; Zhang, Kaihong; Liu, Malin; Shao, Youlin; Tang, Chunhe

    2014-01-01

    Highlights: • High temperature oxidation tests of SiC coating in TRISO particles were carried out. • The dynamic oxidation process was established. • Oxidation mechanisms were proposed. • The existence of silicon oxycarbides at the SiO 2 /SiC interface was demonstrated. • Carbon was detected at the interface at high temperatures and long oxidation time. - Abstract: High temperature oxidation behavior of SiC coatings in tristructural-isotropic (TRISO) coated particles is crucial to the in-pile safety of fuel particles for a high temperature gas cooled reactor (HTGR). The postulated accident condition of air ingress was taken into account in evaluating the reliability of the SiC layer. Oxidation tests of SiC coatings were carried out in the ranges of temperature between 800 and 1600 °C and time between 1 and 48 h in air atmosphere. Based on the microstructure evolution of the oxide layer, the mechanisms and kinetics of the oxidation process were proposed. The existence of silicon oxycarbides (SiO x C y ) at the SiO 2 /SiC interface was demonstrated by X-ray photospectroscopy (XPS) analysis. Carbon was detected by Raman spectroscopy at the interface under conditions of very high temperatures and long oxidation time. From oxidation kinetics calculation, activation energies were 145 kJ/mol and 352 kJ/mol for the temperature ranges of 1200–1500 °C and 1550–1600 °C, respectively

  20. Metal-coated optical fibers for high temperature sensing applications

    Science.gov (United States)

    Fidelus, Janusz D.; Wysokiński, Karol; Stańczyk, Tomasz; Kołakowska, Agnieszka; Nasiłowski, Piotr; Lipiński, Stanisław; Tenderenda, Tadeusz; Nasiłowski, Tomasz

    2017-10-01

    An novel low-temperature method was used to enhance the corrosion resistance of copper or gold-coated optical fibers. A characterization of the elaborated materials and reports on selected studies such as cyclic temperature tests together with tensile tests is presented. Gold-coated optical fibers are proposed as a component of optical fiber sensors working in oxidizing atmospheres under temperatures exceeding 900 °C.

  1. Recent developments in high temperature coatings for gas turbine airfoils

    Science.gov (United States)

    Goward, G. W.

    1983-01-01

    The importance of coatings for hot section airfoils has increased with the drive for more cost-effective use of fuel in a wide variety of gas turbine engines. Minor additions of silicon have been found to appreciably increase the oxidation resistance of plasma-sprayed NiCoCrAlY coatings on a single crystal nickel-base superalloy. Increasing the chromium content of MCrAlY coatings substantially increases the resistance to acidic (Na2SO4-SO3) hot corrosion at temperatures of about 1300 F (704 C) but gives no significant improvement beyond contemporary coatings in the range of 1600 F (871 C). Surface enrichment of MCrAlY coatings with silicon also gives large increases in resistance to acidic hot corrosion in the 1300 F region. The resistance to the thermal stress-induced spalling of zirconia-based thermal barrier coatings has been improved by lowering coating stresses with segmented structures and by controlling the substrate temperature during coating fabrication.

  2. Coated particle fuel for high temperature gas cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Verfondern, Karl; Nabielek, Heinz [Research Center Julich (FZJ), Julich (Germany); Kendall, James M. [Global Virtual L1c, Prescott (United States)

    2007-10-15

    applications at 850-900 .deg. C and for process heat/hydrogen generation applications with 950 .deg. C outlet temperatures. There is a clear set of standards for modern high quality fuel in terms of low levels of heavy metal contamination, manufacture-induced particle defects during fuel body and fuel element making, irradiation/accident induced particle failures and limits on fission product release from intact particles. While gas-cooled reactor design is still open-ended with blocks for the prismatic and spherical fuel elements for the pebble-bed design, there is near worldwide agreement on high quality fuel: a 500 {mu}m diameter UO{sub 2} kernel of 10% enrichment is surrounded by a 100 {mu}m thick sacrificial buffer layer to be followed by a dense inner pyrocarbon layer, a high quality silicon carbide layer of 35 {mu}m thickness and theoretical density and another outer pyrocarbon layer. Good performance has been demonstrated both under operational and under accident conditions, i.e. to 10% FIMA and maximum 1600 .deg. C afterwards. And it is the wide-ranging demonstration experience that makes this particle superior. Recommendations are made for further work: 1. Generation of data for presently manufactured materials, e.g. SiC strength and strength distribution, PyC creep and shrinkage and many more material data sets. 2. Renewed start of irradiation and accident testing of modern coated particle fuel. 3. Analysis of existing and newly created data with a view to demonstrate satisfactory performance at burnups beyond 10% FIMA and complete fission product retention even in accidents that go beyond 1600 .deg. C for a short period of time. This work should proceed at both national and international level.

  3. Coated particle fuel for high temperature gas cooled reactors

    International Nuclear Information System (INIS)

    Verfondern, Karl; Nabielek, Heinz; Kendall, James M.

    2007-01-01

    and for process heat/hydrogen generation applications with 950 .deg. C outlet temperatures. There is a clear set of standards for modern high quality fuel in terms of low levels of heavy metal contamination, manufacture-induced particle defects during fuel body and fuel element making, irradiation/accident induced particle failures and limits on fission product release from intact particles. While gas-cooled reactor design is still open-ended with blocks for the prismatic and spherical fuel elements for the pebble-bed design, there is near worldwide agreement on high quality fuel: a 500 μm diameter UO 2 kernel of 10% enrichment is surrounded by a 100 μm thick sacrificial buffer layer to be followed by a dense inner pyrocarbon layer, a high quality silicon carbide layer of 35 μm thickness and theoretical density and another outer pyrocarbon layer. Good performance has been demonstrated both under operational and under accident conditions, i.e. to 10% FIMA and maximum 1600 .deg. C afterwards. And it is the wide-ranging demonstration experience that makes this particle superior. Recommendations are made for further work: 1. Generation of data for presently manufactured materials, e.g. SiC strength and strength distribution, PyC creep and shrinkage and many more material data sets. 2. Renewed start of irradiation and accident testing of modern coated particle fuel. 3. Analysis of existing and newly created data with a view to demonstrate satisfactory performance at burnups beyond 10% FIMA and complete fission product retention even in accidents that go beyond 1600 .deg. C for a short period of time. This work should proceed at both national and international level

  4. Tribological behavior of zirconium coatings in high temperature helium

    International Nuclear Information System (INIS)

    Cachon, Lionel; Albaladejo, Serge; Taraud, Pascal

    2005-01-01

    In France, a comprehensive research and development program is leaded by the CEA, since 2001, for the Gas Cooled Reactor (GCR) project using helium as cooling fluid, in order to establish the feasibility of the technology of an early VHTR prototype to be started by 2015, and then to qualify the generic VHTR technology, so as to meet similar objectives for the GFR. In this frame a tribology program has been launched. The purpose of the work presented in this paper is to describe the CEA Helium tribology study: high temperature gas cooled reactors require wear protection (thermal barriers, control rod drive mechanisms, reactor internals, ...). Tests in helium atmosphere are necessary to be fully representative of tribological environments and finally to check the possible materials or coatings which can provide a reliable answer to these situations. The main characteristics and first experimental results are thus described. This paper focus on tribology tests leaded in the temperature range 800-1000degC, on ceramic (ZrO 2 -Y 2 O 3 ) with and without solid lubricant like CaF2). (author)

  5. Diffusional aspects of the high-temperature oxidation of protective coatings

    Science.gov (United States)

    Nesbitt, J. A.

    1989-01-01

    The role of diffusional transport associated with the high-temperature oxidation of coatings is examined, with special attention given to the low-pressure plasma spraying MCrAl-type overlay coatings and similar Ni-base alloys which form protective AlO3 scales. The use of diffusional analysis to predict the minimum solute concentration necessary to form and grow a solute oxide scale is illustrated. Modeling procedures designed to simulate the diffusional transport in coatings and substrates are presented to show their use in understanding coating degradation, predicting the protective life of a coating, and evaluating various coating parameters to guide coating development.

  6. Application of aluminum diffusion coatings to mitigate the KCl-induced high-temperature corrosion

    DEFF Research Database (Denmark)

    Kiamehr, Saeed; Lomholt, T. N.; Dahl, Kristian Vinter

    2017-01-01

    Pack cementation was used to produce Fe1−xAl and Fe2Al5 diffusion coatings on ferritic-martensitic steel P91 and a Ni2Al3 diffusion coating on pure nickel. The performance of diffusion coatings against high-temperature corrosion induced by potassium chloride (KCl) was evaluated by exposing...

  7. High Temperature Dry Sliding Friction and Wear Performance of Laser Cladding WC/Ni Composite Coating

    Directory of Open Access Journals (Sweden)

    YANG Jiao-xi

    2016-06-01

    Full Text Available Two different types of agglomerate and angular WC/Ni matrix composite coatings were deposited by laser cladding. The high temperature wear resistance of these composite coatings was tested with a ring-on-disc MMG-10 apparatus. The morphologies of the worn surfaces were observed using a scanning electron microscopy (SEM equipped with an energy dispersive spectroscopy (EDS for elemental composition. The results show that the high temperature wear resistance of the laser clad WC/Ni-based composite coatings is improved significantly with WC mass fraction increasing. The 60% agglomerate WC/Ni composite coating has optimal high temperature wear resistance. High temperature wear mechanism of 60% WC/Ni composite coating is from abrasive wear of low temperature into composite function of the oxidation wear and abrasive wear.

  8. The High-Temperature Resistance Properties of Polysiloxane/Al Coatings with Low Infrared Emissivity

    Directory of Open Access Journals (Sweden)

    Jun Zhao

    2018-03-01

    Full Text Available High-temperature-resistant coatings with low infrared emissivity were prepared using polysiloxane resin and flake aluminum as the adhesive and pigment, respectively. The heat resistance mechanisms of the polysiloxane/Al coating were systematically investigated. The composition, surface morphology, infrared reflectance spectra, and thermal expansion dimension (ΔL of the coatings were characterized by X-ray photoelectron spectroscopy (XPS, field emission scanning electron microscopy (FE-SEM, Fourier transform infrared spectroscopy, and thermal mechanical analysis (TMA, respectively. The results show that thermal decomposition of the resin and mismatch of ΔL between the coating and the substrate facilitate the high temperature failure of the coating. A suitable amount of flake aluminum pigments could restrain the thermal decomposition of the resin and could increase the match degree of ΔL between the coating and substrate, leading to an enhanced thermal resistance of the coating. Our results find that a coating with a pigment to binder ratio (P/B ratio of 1.0 could maintain integrity until 600 °C, and the infrared emissivity was as low as 0.27. Hence, a coating with high-temperature resistance and low emissivity was obtained. Such coatings can be used for infrared stealth technology or energy savings in high-temperature equipment.

  9. High-temperature protective coatings for C/SiC composites

    OpenAIRE

    Xiang Yang; Chen Zhao-hui; Cao Feng

    2014-01-01

    Carbon fiber-reinforced silicon carbide (C/SiC) composites were well-established light weight materials combining high specific strength and damage tolerance. For high-temperature applications, protective coatings had to provide oxidation and corrosion resistance. The literature data introduced various technologies and materials, which were suitable for the application of coatings. Coating procedures and conditions, materials design limitations related to the reactivity of the components of C...

  10. Research on infrared radiation characteristics of Pyromark1200 high-temperature coating

    Science.gov (United States)

    Song, Xuyao; Huan, Kewei; Dong, Wei; Wang, Jinghui; Zang, Yanzhe; Shi, Xiaoguang

    2014-11-01

    Pyromark 1200 (Tempil Co, USA), which is a type of high-temperature high-emissivity coating, is silicon-based with good thermal radiation performance. Its stably working condition is at the temperature range 589~922 K thus a wide range of applications in industrial, scientific research, aviation, aerospace and other fields. Infrared emissivity is one of the most important factors in infrared radiation characteristics. Data on infrared spectral emissivity of Pyromark 1200 is in shortage, as well as the reports on its infrared radiation characteristics affected by its spray painting process, microstructure and thermal process. The results of this research show that: (1) The coating film critical thickness on the metal base is 10μm according to comparison among different types of spray painting process, coating film thickness, microstructure, which would influence the infrared radiation characteristics of Pyromark 1200 coating. The infrared spectral emissivity will attenuate when the coating film thickness is lower or much higher than that. (2) Through measurements, the normal infrared radiation characteristics is analyzed within the range at the temperature range 573~873 K under normal atmospheric conditions, and the total infrared spectral emissivity of Pyromark 1200 coating is higher than 0.93 in the 3~14 μm wavelength range. (3) The result of 72-hour aging test at the temperature 673 K which studied the effect of thermal processes on the infrared radiation characteristics of the coating shows that the infrared spectral emissivity variation range is approximately 0.01 indicating that Pyromark 1200 coating is with good stability. Compared with Nextel Velvet Coating (N-V-C) which is widely used in optics field, Pyromark 1200 high-temperature coating has a higher applicable temperature and is more suitable for spraying on the material surface which is in long-term operation under high temperature work conditions and requires high infrared spectral emissivity.

  11. High-temperature protective coatings for C/SiC composites

    Directory of Open Access Journals (Sweden)

    Xiang Yang

    2014-12-01

    Full Text Available Carbon fiber-reinforced silicon carbide (C/SiC composites were well-established light weight materials combining high specific strength and damage tolerance. For high-temperature applications, protective coatings had to provide oxidation and corrosion resistance. The literature data introduced various technologies and materials, which were suitable for the application of coatings. Coating procedures and conditions, materials design limitations related to the reactivity of the components of C/SiC composites, new approaches and coating systems to the selection of protective coatings materials were examined. The focus of future work was on optimization by further multilayer coating systems and the anti-oxidation ability of C/SiC composites at temperatures up to 2073 K or higher in water vapor.

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

    Science.gov (United States)

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

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

  13. Phase Stability in Ultra-High Temperature Refractory Metal Alloys and Coatings

    National Research Council Canada - National Science Library

    Perepezko, John

    2002-01-01

    ...) base alloys such as those in the Mo-Si-B system and the evaluation of thermal barrier and oxidation resistant coatings for these systems requires very high temperature annealing furnaces with long...

  14. Optimization of Arc-Sprayed Ni-Cr-Ti Coatings for High Temperature Corrosion Applications

    Science.gov (United States)

    Matthews, S.; Schweizer, M.

    2013-04-01

    High Cr content Ni-Cr-Ti arc-spray coatings have proven successful in resisting the high temperature sulfidizing conditions found in black liquor recovery boilers in the pulp and paper industry. The corrosion resistance of the coatings is dependent upon the coating composition, to form chromium sulfides and oxides to seal the coating, and on the coating microstructure. Selection of the arc-spray parameters influences the size, temperature and velocity of the molten droplets generated during spraying, which in turn dictates the coating composition and formation of the critical coating microstructural features—splat size, porosity and oxide content. Hence it is critical to optimize the arc-spray parameters in order to maximize the corrosion resistance of the coating. In this work the effect of key spray parameters (current, voltage, spray distance and gas atomizing pressure) on the coating splat thickness, porosity content, oxide content, microhardness, thickness, and surface profile were investigated using a full factorial design of experiment. Based on these results a set of oxidized, porous and optimized coatings were prepared and characterized in detail for follow-up corrosion testing.

  15. Characterization of thermally sprayed coatings for high-temperature wear-protection applications

    International Nuclear Information System (INIS)

    Li, C.C.

    1980-03-01

    Under normal high-temperature gas-cooled reactor (HTGR) operating conditions, faying surfaces of metallic components under high contact pressure are prone to friction, wear, and self-welding damage. Component design calls for coatings for the protection of the mating surfaces. Anticipated operating temperatures up to 850 to 950 0 C (1562 to 1742 0 F) and a 40-y design life require coatings with excellent thermal stability and adequate wear and spallation resistance, and they must be compatible with the HTGR coolant helium environment. Plasma and detonation-gun (D-gun) deposited chromium carbide-base and stabilized zirconia coatings are under consideration for wear protection of reactor components such as the thermal barrier, heat exchangers, control rods, and turbomachinery. Programs are under way to address the structural integrity, helium compatibility, and tribological behavior of relevant sprayed coatings. In this paper, the need for protection of critical metallic components and the criteria for selection of coatings are discussed. The technical background to coating development and the experience with the steam cycle HTGR (HTGR-SC) are commented upon. Coating characterization techniques employed at General Atomic Company (GA) are presented, and the progress of the experimental programs is briefly reviewed. In characterizing the coatings for HTGR applications, it is concluded that a systems approach to establish correlation between coating process parameters and coating microstructural and tribological properties for design consideration is required

  16. Thick sputtered tantalum coatings for high-temperature energy conversion applications

    Energy Technology Data Exchange (ETDEWEB)

    Stelmakh, Veronika, E-mail: stelmakh@mit.edu; Peykov, Daniel; Chan, Walker R.; Senkevich, Jay J.; Joannopoulos, John D.; Soljačić, Marin; Celanovic, Ivan [Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Castillo, Robert; Coulter, Kent; Wei, Ronghua [Materials Engineering Department, Southwest Research Institute, San Antonio, Texas 78238 (United States)

    2015-11-15

    Thick sputtered tantalum (Ta) coatings on polished Inconel were investigated as a potential replacement for bulk refractory metal substrates used for high-temperature emitters and absorbers in thermophotovoltaic energy conversion applications. In these applications, high-temperature stability and high reflectance of the surface in the infrared wavelength range are critical in order to sustain operational temperatures and reduce losses due to waste heat. The reflectance of the coatings (8 and 30 μm) was characterized with a conformal protective hafnia layer as-deposited and after one hour anneals at 700, 900, and 1100 °C. To further understand the high-temperature performance of the coatings, the microstructural evolution was investigated as a function of annealing temperature. X-ray diffraction was used to analyze the texture and residual stress in the coatings at four reflections (220, 310, 222, and 321), as-deposited and after anneal. No significant changes in roughness, reflectance, or stress were observed. No delamination or cracking occurred, even after annealing the coatings at 1100 °C. Overall, the results of this study suggest that the thick Ta coatings are a promising alternative to bulk substrates and pave the way for a relatively low-cost and easily integrated platform for nanostructured devices in high-temperature energy conversion applications.

  17. High temperature glass thermal control structure and coating. [for application to spacecraft reusable heat shielding

    Science.gov (United States)

    Stewart, D. A.; Goldstein, H. E.; Leiser, D. B. (Inventor)

    1983-01-01

    A high temperature stable and solar radiation stable thermal control coating is described which is useful either as such, applied directly to a member to be protected, or applied as a coating on a re-usable surface insulation (RSI). It has a base coat layer and an overlay glass layer. The base coat layer has a high emittance, and the overlay layer is formed from discrete, but sintered together glass particles to give the overlay layer a high scattering coefficient. The resulting two-layer space and thermal control coating has an absorptivity-to-emissivity ratio of less than or equal to 0.4 at room temperature, with an emittance of 0.8 at 1200 F. It is capable of exposure to either solar radiation or temperatures as high as 2000 F without significant degradation. When used as a coating on a silica substrate to give an RSI structure, the coatings of this invention show significantly less reduction in emittance after long term convective heating and less residual strain than prior art coatings for RSI structures.

  18. Microstructure of Al-Si Slurry Coatings on Austenitic High-Temperature Creep Resisting Cast Steel

    Directory of Open Access Journals (Sweden)

    Agnieszka E. Kochmańska

    2018-01-01

    Full Text Available This paper presents the results of microstructural examinations on slurry aluminide coatings using scanning electron microscopy, X-ray microanalysis, and X-ray diffraction. Aluminide coatings were produced in air atmosphere on austenitic high-temperature creep resisting cast steel. The function of aluminide coatings is the protection of the equipment components against the high-temperature corrosion in a carburising atmosphere under thermal shock conditions. The obtained coatings had a multilayered structure composed of intermetallic compounds. The composition of newly developed slurry was powders of aluminium and silicon; NaCl, KCl, and NaF halide salts; and a water solution of a soluble glass as an inorganic binder. The application of the inorganic binder in the slurry allowed to produce the coatings in one single step without additional annealing at an intermediate temperature as it is when applied organic binder. The coatings were formed on both: the ground surface and on the raw cast surface. The main technological parameters were temperature (732–1068°C and time of annealing (3.3–11.7 h and the Al/Si ratio (4–14 in the slurry. The rotatable design was used to evaluate the effect of the production parameters on the coatings thickness. The correlation between the technological parameters and the coating structure was determined.

  19. HIGH TEMPERATURE EROSION WEAR OF CERMET PARTICLES REINFORCED SELF-FLUXING ALLOY MATRIX HVOF SPRAYED COATINGS

    Directory of Open Access Journals (Sweden)

    Andrei Surzhenkov

    2015-09-01

    Full Text Available In the present paper, the resistance of high velocity oxy-fuel (HVOF sprayed TiC-NiMo and Cr3C2-Ni cermet particles reinforced NiCrSiB self-fluxing alloy matrix coatings to high temperature erosion wear is studied. Microstructure of the coatings was examined by SEM, phase composition was determined by XRD. A four-channel centrifugal particle accelerator was applied to study the high temperature erosion wear of the coatings. The impact angles were 30 and 90 degrees, initial particle velocity was 50 m/s, temperature of the test - 650 degrees. Volume wear of the coatings was calculated and compared to the respective values of the reference materials. Wear mechanisms were studied by SEM.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7617

  20. Refractory porcelain enamel passive-thermal-control coating for high-temperature superalloys

    Science.gov (United States)

    Levin, H.; Auker, B. H.; Gardos, M. N.

    1973-01-01

    Study was conducted to match thermal expansion coefficients thereby preventing enamels from cracking. Report discusses various enamel coatings that are applied to two different high-temperature superalloys. Study may be of interest to manufacturers of chemical equipment, furnaces, and metal components intended for high-temperature applications.

  1. Surface coating of ceria nanostructures for high-temperature oxidation protection

    Science.gov (United States)

    Aadhavan, R.; Bhanuchandar, S.; Babu, K. Suresh

    2018-04-01

    Stainless steels are used in high-temperature structural applications but suffer from degradation at an elevated temperature of operation due to thermal stress which leads to spallation. Ceria coating over chromium containing alloys induces protective chromia layer formation at alloy/ceria interface thereby preventing oxidative degradation. In the present work, three metals of differing elemental composition, namely, AISI 304, AISI 410, and Inconel 600 were tested for high-temperature stability in the presence and absence of ceria coating. Nanoceria was used as the target to deposit the coating through electron beam physical vapor deposition method. After isothermal oxidation at 1243 K for 24 h, Ceria coated AISI 304 and Inconel 600 exhibited a reduced rate of oxidation by 4 and 1 orders, respectively, in comparison with the base alloy. The formation of spinel structure was found to be lowered in the presence of ceria due to the reduced migration of cations from the alloy.

  2. Thermal Processing Effects on the Adhesive Strength of PS304 High Temperature Solid Lubricant Coatings

    Science.gov (United States)

    DellaCorte, Christopher; Edmonds, Brian J.; Benoy, Patricia A.

    2001-01-01

    In this paper the effects of post deposition heat treatments on the cohesive and adhesive strength properties of PS304, a plasma sprayed nickel-chrome based, high temperature solid lubricant coating deposited on stainless steel, are studied. Plasma spray deposited coating samples were exposed in air at temperatures from 432 to 650 C for up to 500 hr to promote residual stress relief, enhance particle to particle bonding and increase coating to substrate bond strength. Coating pull-off strength was measured using a commercial adhesion tester that utilizes 13 mm diameter aluminum pull studs attached to the coating surface with epoxy. Pull off force was automatically recorded and converted to coating pull off strength. As deposited coating samples were also tested as a baseline. The as-deposited (untreated) samples either delaminated at the coating-substrate interface or failed internally (cohesive failure) at about 17 MPa. Samples heat treated at temperatures above 540 C for 100 hr or at 600 C or above for more than 24 hr exhibited strengths above 31 MPa, nearly a two fold increase. Coating failure occurred inside the body of the coating (cohesive failure) for nearly all of the heat-treated samples and only occasionally at the coating substrate interface (adhesive failure). Metallographic analyses of heat-treated coatings indicate that the Nickel-Chromium binder in the PS304 appears to have segregated into two phases, a high nickel matrix phase and a high chromium precipitated phase. Analysis of the precipitates indicates the presence of silicon, a constituent of a flow enhancing additive in the commercial NiCr powder. The exact nature and structure of the precipitate phase is not known. This microstructural change is believed to be partially responsible for the coating strength increase. Diffusion bonding between particles may also be playing a role. Increasing the heat treatment temperature, exposure time or both accelerate the heat treatment process. Preliminary

  3. Diffusion barrier coatings for high temperature corrosion resistance of advanced carbon/carbon composites

    International Nuclear Information System (INIS)

    Singh Raman, K.S.

    2000-01-01

    Carbon possesses an excellent combination of mechanical and thermal properties, viz., excellent creep resistance at temperatures up to 2400 deg C in non-oxidizing environment and a low thermal expansion coefficient. These properties make carbon a potential material for very high temperature applications. However, the use of carbon materials at high temperatures is considerably restricted due to their extremely poor oxidation resistance at temperatures above 400 deg C. The obvious choice for improving high temperature oxidation resistance of such materials is a suitable diffusion barrier coating. This paper presents an overview of recent developments in advanced diffusion- and thermal-barrier coatings for ceramic composites, with particular reference to C/C composites. The paper discusses the development of multiphase and multi-component ceramic coatings, and recent investigations on the oxidation resistance of the coated C/C composites. The paper also discusses the cases of innovative engineering solutions for traditional problems with the ceramic coatings, and the scope of intelligent processing in developing coatings for the C/C composites. Copyright (2000) AD-TECH - International Foundation for the Advancement of Technology Ltd

  4. Effects of AlN Coating Layer on High Temperature Characteristics of Langasite SAW Sensors

    Directory of Open Access Journals (Sweden)

    Lin Shu

    2016-09-01

    Full Text Available High temperature characteristics of langasite surface acoustic wave (SAW devices coated with an AlN thin film have been investigated in this work. The AlN films were deposited on the prepared SAW devices by mid-frequency magnetron sputtering. The SAW devices coated with AlN films were measured from room temperature to 600 °C. The results show that the SAW devices can work up to 600 °C. The AlN coating layer can protect and improve the performance of the SAW devices at high temperature. The SAW velocity increases with increasing AlN coating layer thickness. The temperature coefficients of frequency (TCF of the prepared SAW devices decrease with increasing thickness of AlN coating layers, while the electromechanical coupling coefficient (K2 of the SAW devices increases with increasing AlN film thickness. The K2 of the SAW devices increases by about 20% from room temperature to 600 °C. The results suggest that AlN coating layer can not only protect the SAW devices from environmental contamination, but also improve the K2 of the SAW devices.

  5. Evaluation of High Temperature Particle Erosion Resistance of Vanadium-Boride Coating

    International Nuclear Information System (INIS)

    Lee, E. Y.; Kim, J. H.; Jeong, S. I.; Lee, S. H.; Eum, G. W.

    2015-01-01

    The components in ultra super critical (USC) steam turbine, which is under development for high efficient power generation, are encountering harsher solid particle erosion by iron oxide scales than ones in the existing steam turbines. Therefore, the currently used boride coating will not be able to hold effective protection from particle erosion in USC system and should be replaced by new particle erosion resistant coatings. One of the best protective coatings developed for USC steam turbine parts was found to be vanadium-boride (V-boride) coating which has a hardness of about 3000 HV, much higher than that of boride, 1600∼2000 HV. In order to evaluate particle erosion resistance of the various coatings such as V-boride, boride and Cr-carbide coatings at high temperature, particle erosion test equipment were designed and manufactured. In addition, erosion particle velocity was simulated using FLUENT software based on semi-implicity method for pressure linked equations revised (SIMPLER). Based on experimental results of this work, the vanadium-boride coating was found to be superior to others and to be a candidate coating to replace the boride coating

  6. Evaluation of High Temperature Particle Erosion Resistance of Vanadium-Boride Coating

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E. Y.; Kim, J. H.; Jeong, S. I. [Andong National University, Andong (Korea, Republic of); Lee, S. H.; Eum, G. W. [Corporate R and D Institute Doosan Heavy Industries and Construction Co., Changwon (Korea, Republic of)

    2015-04-15

    The components in ultra super critical (USC) steam turbine, which is under development for high efficient power generation, are encountering harsher solid particle erosion by iron oxide scales than ones in the existing steam turbines. Therefore, the currently used boride coating will not be able to hold effective protection from particle erosion in USC system and should be replaced by new particle erosion resistant coatings. One of the best protective coatings developed for USC steam turbine parts was found to be vanadium-boride (V-boride) coating which has a hardness of about 3000 HV, much higher than that of boride, 1600∼2000 HV. In order to evaluate particle erosion resistance of the various coatings such as V-boride, boride and Cr-carbide coatings at high temperature, particle erosion test equipment were designed and manufactured. In addition, erosion particle velocity was simulated using FLUENT software based on semi-implicity method for pressure linked equations revised (SIMPLER). Based on experimental results of this work, the vanadium-boride coating was found to be superior to others and to be a candidate coating to replace the boride coating.

  7. Study on coated layer material performance of coated particle fuel FBR (2). High temperature property and capability of coating to thick layer of TiN

    International Nuclear Information System (INIS)

    Naganuma, Masayuki; Mizuno, Tomoyasu

    2002-08-01

    'Helium Gas Cooled Coated Particle Fuel FBR' is one of attractive core concepts in the Feasibility Study on Commercialized Fast Reactor Cycle System in Japan, and the design study is presently proceeded. As one of key technologies of this concept, the coated layer material is important, and ceramics is considered to be a candidate material because of the superior refractory. Based on existing knowledge, TiN is regarded to be a possible candidate material, to which some property tests and evaluations have been conducted. In this study, preliminary tests about the high temperature property and the capability of thick layer coating of TiN have been conducted. Results of these tests come to the following conclusions. Heating tests of two kinds of TiN layer specimens coated by PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition) were conducted. As a result, as for CVD coating specimens, remarkable charge was not observed on the layer up to 2,000degC, therefore we concluded that the layer by CVD had applicability up to high temperature of actual operation level. On the other hand, as for PVD coating specimens, an unstable behavior that the layer changed to a mesh like texture was observed on a 2,000degC heated specimen, therefore the applied PVD method is not considered to be promising as the coating technique. The surface conditions of some parts inside CVD device were investigated in order to evaluate possibility of TiN thick coating (∼100 μm). As a result, around 500 μm of TiN coating layer was observed on the condition of multilayer. Therefore, we conclude that CVD has capability of coating up to thick layer in actual coated particle fuel fabrication. (author)

  8. Silicon coating treatment to improve high temperature corrosion resistance of 9%Cr steels

    International Nuclear Information System (INIS)

    Hill, M.P.

    1989-01-01

    A silicon coating process is described which confers good protection on 9%Cr steels and alloys in CO 2 based atmospheres at high temperatures and pressures. The coatings are formed by decomposition of silane at temperatures above 720 K. Protective layers are typically up to 1 μm thick. The optimum coating conditions are discussed. The chemical state of the coatings has been investigated by X-ray photoelectron spectroscopy and has demonstrated the importance of avoiding silicon oxide formation during processing. Corrosion testing has been carried out for extended periods, up to 20 000 h, at temperatures between 753 and 853 K, in a simulated advanced gas cooled reactor gas at 4 MPa pressure. Benefit factors of up to 60 times have been measured for 9%Cr steels. Even higher values have been measured for 9Cr-Fe binary alloy on which a 1 μm coating was sufficient to eliminate significant oxidation over 19 000 h except at the specimen edges. The mechanism of protection is discussed. It is suggested that a silicon surface coating for protecting steels from high temperature corrosion has some advantages over adding silicon to the bulk metal. (author)

  9. High-temperature strength of TiC-coated SUS316 stainless steel

    International Nuclear Information System (INIS)

    Kaneko, K.; Furuya, Y.; Kikuchi, M.

    1992-01-01

    Some ceramics-coated metals are nominated as first-wall material. TiC-coated type 316 stainless steel is expected to be superior to other materials in high-temperature strength and in its endurance properties at heavy irradiation. Delamination between ceramics layer and base-metal is considered to be one of the most important problems when such ceramics-coated metals are used in a temperature field with a gradient such as that of the first wall. In this report, the high-temperature strength of TiC-coated type 316 stainless steel, which should be that of the first wall of the fusion reactor, is investigated experimentally and computationally. A simple and precise thermal-stress testing system is developed. The effects of surface roughness as well as of the thermal stress and the residual stress on the bonding strength are investigated. The experimental and numerical results on the residual-stress distribution are compared with each other to confirm the reliability of the inelastic analysis using the finite-element method (FEM). It is expected that a suitable surface roughness makes the residual stress in the coated film small. The optimum range for the TiC-coating temperature is found using inelastic FEM analysis at the heating conditions used in the experiments. (orig.)

  10. Sintering Characteristics of Multilayered Thermal Barrier Coatings Under Thermal Gradient and Isothermal High Temperature Annealing Conditions

    Science.gov (United States)

    Rai, Amarendra K.; Schmitt, Michael P.; Bhattacharya, Rabi; Zhu, Dongming; Wolfe, Douglas E.

    2014-01-01

    Pyrochlore oxides have most of the relevant attributes for use as next generation thermal barrier coatings such as phase stability, low sintering kinetics and low thermal conductivity. One of the issues with the pyrochlore oxides is their lower toughness and therefore higher erosion rate compared to the current state-of-the-art TBC material, yttria (6 to 8 wt%) stabilized zirconia (YSZ). In this work, sintering characteristics were investigated for novel multilayered coating consisted of alternating layers of pyrochlore oxide viz Gd2Zr2O7 and t' low k (rare earth oxide doped YSZ). Thermal gradient and isothermal high temperature (1316 C) annealing conditions were used to investigate sintering and cracking in these coatings. The results are then compared with that of relevant monolayered coatings and a baseline YSZ coating.

  11. A study for preparation of Ti-Fe coating by high temperature sintering method

    International Nuclear Information System (INIS)

    Hu Yonghai

    1995-03-01

    A new technology for preparation of Ti-Fe alloy coating on the steel substrate was investigated by high temperature sintering method. The pulp of titanium hydride powder was coated on the cleaned steel substrate, then heated in vacuum for desorption of hydrogen and sintered at high temperature in argon atmosphere for forming Ti-Fe alloy coating. The electron probe analysis shows a strong coherent diffusion layer formed between the elements of titanium and iron. X-ray diffraction analysis indicates that the coating consists of α-Ti, TiFe and TiFe 2 three phases. The wear resistance of the coating is twice as large as that of grey cast iron and the hardness determined can reach 7300∼7800 N/mm 2 . The coating is almost porous free. The corrosion potential increases with the time and the corrosion resistance is near to that of pure titanium. The working life of ridge-type diaphragm valve coated by Ti-Fe alloy for carbonization tower of alkali factories is five times higher than that of valve made of grey cast iron. Therefore, this new technology can be widely used in metallurgical, chemical and nuclear industries. (9 figs., 10 tabs.)

  12. Microstructural characterization of thermal barrier coating on Inconel 617 after high temperature oxidation

    Directory of Open Access Journals (Sweden)

    Mohammadreza Daroonparvar

    2013-06-01

    Full Text Available A turbine blade was protected against high temperature corrosion and oxidation by thermal barrier coatings (TBCsusing atmospheric plasma spraying technique (APS on a Ni-based superalloy (Inconel 617. The coatings (NiCr6AlY/ YSZ and NiCr10AlY/YSZ consist of laminar structure with substantial interconnected porosity transferred oxygen from Yittria stabilized Zirconia (YSZ layer toward the bond coat (NiCrAlY. Hence, a thermally grown oxide layer (TGO was formed on the metallic bond coat and internal oxidation of the bond coat occurred during oxidation. The TBC systems were oxidized in a normal electrically heated furnace at 1150 °C for 18, 22, 26, 32 and 40h.Microstructural characterization of coatings demonstrated that the growth of the TGO layer on the nickel alloy with 6wt. % Al is more rapid than TGO with 10wt. % Al. In addition, many micro-cracks were observed at the interface of NiCr6AlY/YSZ. X-ray diffraction analysis (XRD showed the existence of detrimental oxides such as NiCr2O4, NiCrO3 and NiCrO4 in the bond coat containing 6wt. % Al, accompanied by rapid volume expansion causing the destruction of TBC. In contrast, in the bond coat with 10wt. % Al, NiO, Al2O3and Cr2O3 oxides were formed while very low volume expansion occurred. The oxygen could not penetrate into the TGO layer of bond coat with 10 wt. % Al during high temperature oxidation and the detrimental oxides were not extensively formed within the bond coat as more oxygen was needed. The YSZ with higher Al content showed higher oxidation resistance.

  13. Copper Metallic Substrates for High Temperature Superconducting Coated Conductors

    National Research Council Canada - National Science Library

    Yust, Nicholas A; Nekkanti, Rama; Brunke, Lyle B; Srinivasan, Raghavan; Barnes, Paul N

    2006-01-01

    .... Detailed x-ray diffraction (XRD) studies and orientation imaging microscopy (OIM) were performed to measure the in-plane alignment, out-of-plane alignment, and microtexture at various deformation levels and annealing temperatures...

  14. Oxidation Study of an Ultra High Temperature Ceramic Coatings Based on HfSiCN

    Science.gov (United States)

    Sacksteder, Dagny; Waters, Deborah L.; Zhu, Dongming

    2018-01-01

    High temperature fiber-reinforced ceramic matrix composites (CMCs) are important for aerospace applications because of their low density, high strength, and significantly higher-temperature capabilities compared to conventional metallic systems. The use of the SiCf/SiC and Cf/SiC CMCs allows the design of lighter-weight, more fuel efficient aircraft engines and also more advanced spacecraft airframe thermal protection systems. However, CMCs have to be protected with advanced environmental barrier coatings when they are incorporated into components for the harsh environments such as in aircraft engine or spacecraft applications. In this study, high temperature oxidation kinetics of an advanced HfSiCN coating on Cf/SiC CMC substrates were investigated at 1300 C, 1400 C, and 1500 C by using thermogravimetric analysis (TGA). The coating oxidation reaction parabolic rate constant and activation energy were estimated from the experimental results. The oxidation reaction studies showed that the coatings formed the most stable, predominant HfSiO4-HfO2 scales at 1400 C. A peroxidation test at 1400 C then followed by subsequent oxidation tests at various temperatures also showed more adherent scales and slower scale growth because of reduced the initial transient oxidation stage and increased HfSiO4-HfO2 content in the scales formed on the HfSiCN coatings.

  15. High temperature oxidation and corrosion in marine environments of thermal spray deposited coatings

    International Nuclear Information System (INIS)

    Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Stergioudis, G.; Skolianos, S.; Chrissafis, K.

    2008-01-01

    Flame spraying is a widely used technique for depositing a great variety of materials in order to enforce the mechanical or the anticorrosion characteristics of the substrate. Its high rate application is due to the rapidity of the process, its effectiveness and its low cost. In this work, flame-sprayed Al coatings are deposited on low carbon steels in order to enhance their anticorrosion performance. The main adhesion mechanism of the coating is mechanical anchorage, which can provide the necessary protection to steel used in several industrial and constructive applications. To evaluate the corrosion resistance of the coating, the as-coated samples are subjected in a salt spray chamber and in elevated temperature environments. The examination and characterization of the corroded samples is done by scanning electron microscopy and X-ray diffraction analysis. The as-formed coatings are extremely rough and have a lamellic homogeneous morphology. It is also found that Al coatings provide better protection in marine atmospheres, while at elevated temperatures a thick oxide layer is formed, which can delaminate after long oxidation periods due to its low adherence to the underlying coating, thus eliminating the substrate protection

  16. High temperature tribological properties of plasma-sprayed metallic coatings containing ceramic particles

    International Nuclear Information System (INIS)

    Dallaire, S.; Legoux, J.G.

    1995-01-01

    For sealing a moving metal component with a dense silica-based ceramic pre-heated at 800 C, coatings with a low coefficient of friction and moderate wear loss are required. As reported previously, plasma-sprayed coatings containing solid lubricants could reduce sliding wear in high-temperature applications. Plasma-sprayed metal-based coatings containing ceramic particles have been considered for high temperature sealing. Selected metal powders (NiCoCrAlY, CuNi, CuNiIn, Ag, Cu) and ceramic particles (boron nitride, Zeta-B ceramic) were agglomerated to form suitable spray powders. Plasma-sprayed composite coatings and reference materials were tested in a modified pin-on-disc apparatus in which the stationary disc consisted of a dense silica-based ceramic piece initially heated at 800 C and allowed to cool down during tests. The influence of single exposure and repeated contacts with a dense silica-based ceramic material pre-heated to 800 C on the coefficient of friction, wear loss and damage to the ceramic piece was evaluated. Being submitted to a single exposure at high temperature, coatings containing malleable metals such as indium, silver and copper performed well. The outstanding tribological characteristics of the copper-Zeta-B ceramic coating was attributed to the formation of a glazed layer on the surface of this coating which lasted over exposures to high temperature. This glazed layer, composed of fine oxidation products, provided a smooth and polished surface and helped maintaining the coefficient of friction low

  17. High temperature resistant cermet and ceramic compositions. [for thermal resistant insulators and refractory coatings

    Science.gov (United States)

    Phillips, W. M. (Inventor)

    1978-01-01

    High temperature oxidation resistance, high hardness and high abrasion and wear resistance are properties of cermet compositions particularly to provide high temperature resistant refractory coatings on metal substrates, for use as electrical insulation seals for thermionic converters. The compositions comprise a sintered body of particles of a high temperature resistant metal or metal alloy, preferably molybdenum or tungsten particles, dispersed in and bonded to a solid solution formed of aluminum oxide and silicon nitride, and particularly a ternary solid solution formed of a mixture of aluminum oxide, silicon nitride and aluminum nitride. Ceramic compositions comprising a sintered solid solution of aluminum oxide, silicon nitride and aluminum nitride are also described.

  18. Multilayer oxidation resistant coating for SiC coated carbon/carbon composites at high temperature

    International Nuclear Information System (INIS)

    Li Hejun; Jiao Gengsheng; Li Kezhi; Wang Chuang

    2008-01-01

    To prevent carbon/carbon (C/C) composites from oxidation, a multilayer coating based on molybdenum disilicide and titanium disilicide was formed using a two-step pack cementation technique in argon atmosphere. XRD and SEM analysis showed that the internal coating was a bond SiC layer that acts as a buffer layer, and that the external multilayer coating formed in the two-step pack cementation was composed of two MoSi 2 -TiSi 2 -SiC layers. This coating, which is characterized by excellent thermal shock resistance, could effectively protect the composites from exposure to an oxidizing atmosphere at 1773 K for 79 h. The oxidation of the coated C/C composites was primarily due to the reaction of C/C matrix and oxygen diffusing through the penetrable cracks in the coating

  19. Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers

    Science.gov (United States)

    Oksa, M.; Metsäjoki, J.; Kärki, J.

    2015-01-01

    There are over 1000 biomass boilers and about 500 plants using waste as fuel in Europe, and the numbers are increasing. Many of them encounter serious problems with high-temperature corrosion due to detrimental elements such as chlorides, alkali metals, and heavy metals. By HVOF spraying, it is possible to produce very dense and well-adhered coatings, which can be applied for corrosion protection of heat exchanger surfaces in biomass and waste-to-energy power plant boilers. Four HVOF coatings and one arc sprayed coating were exposed to actual biomass co-fired boiler conditions in superheater area with a probe measurement installation for 5900 h at 550 and 750 °C. The coating materials were Ni-Cr, IN625, Fe-Cr-W-Nb-Mo, and Ni-Cr-Ti. CJS and DJ Hybrid spray guns were used for HVOF spraying to compare the corrosion resistance of Ni-Cr coating structures. Reference materials were ferritic steel T92 and nickel super alloy A263. The circulating fluidized bed boiler burnt a mixture of wood, peat and coal. The coatings showed excellent corrosion resistance at 550 °C compared to the ferritic steel. At higher temperature, NiCr sprayed with CJS had the best corrosion resistance. IN625 was consumed almost completely during the exposure at 750 °C.

  20. Kinetics of the process of formation and high-temperature oxidation of electrospark coatings on steel

    International Nuclear Information System (INIS)

    Verkhoturov, A.D.; Chiplik, V.N.; Egorov, F.F.; Lavrenko, V.A.; Podchernyaeva, I.A.; Shemet, V.Z.

    1986-01-01

    This work is a study of the kinetics of formation and of the heat resistance of electrospark coatings based on the composite TiB 2 -Mo with varying molybdenum content. In the process of electrospark alloying they measured the specific erosion of the anode and the increase in weight of the cathode with an accuracy not worse than 5%. Electrospark coatings of TiB 2 -Mo on steel 45 are marked by improved scaling resistance at temperatures above 900 C. Their scaling resistance and also the effectiveness of the process of electrospark alloying increase with increasing content of the phase B-MoB in the coating because molybdenum borate forms during its high-temperature oxidation. Illustrations and table are included

  1. An assessment of thermal spray coating technologies for high temperature corrosion protection

    International Nuclear Information System (INIS)

    Heath, G.R.; Heimgartner, P.; Gustafsson, S.; Irons, G.; Miller, R.

    1997-01-01

    The use of thermally sprayed coatings in combating high temperature corrosion continues to grow in the major industries of chemical, waste incineration, power generation and pulp and paper. This has been driven partially by the development of corrosion resistant alloys, improved knowledge and quality in the thermal spray industry and continued innovation in thermal spray equipment. There exists today an extensive range of thermal spray process options, often with the same alloy solution. In demanding corrosion applications it is not sufficient to just specify alloy and coating method. For the production of reliable coatings the whole coating production envelope needs to be considered, including alloy selection, spray parameters, surface preparation, base metal properties, heat input etc. Combustion, arc-wire, plasma, HVOF and spray+fuse techniques are reviewed and compared in terms of their strengths and limitations to provide cost-effective solutions for high temperature corrosion protection. Arc wire spraying, HP/HVOF and spray+fuse are emerging as the most promising techniques to optimise both coating properties and economic/practical aspects. (orig.)

  2. Tensile toughness test and high temperature fracture analysis of thermal barrier coatings

    International Nuclear Information System (INIS)

    Qian, G.; Nakamura, T.; Berndt, C.C.; Leigh, S.H.

    1997-01-01

    In this paper, an effective fracture toughness test which uses interface fracture mechanics theory is introduced. This method is ideally suited for determining fracture resistance of multilayered thermal barrier coatings (TBCs) consisting of ceramic and bond layers and, unlike other fracture experiments, requires minimal set-up over a simple tensile adhesion test. Furthermore, while other test methods usually use edge cracked specimens, the present test models a crack embedded within the coatings, which is more consistent with actual TBCs where failure initiates from internal voids or defects. The results of combined computational and experimental analysis show that any defects located within the ceramic coating can significantly weaken a TBC, whereas the debonding resistances of the bond coating and its interfaces are found to be much higher. In a separate analysis, the authors have studied fracture behavior of TBCs subjected to thermal loading in a high temperature environment. The computed fracture parameters reveal that when the embedded crack size is on order of the coating thickness, the fracture driving force is comparable to the fracture resistance of the coating found in the toughness test. In addition, the major driving force for fracture derives from the thermal insulating effect across the crack faces rather than the mismatch in the coefficients of thermal expansion. The authors have also investigated the effects of functionally graded material (FGM) within TBCs and found its influences on the fracture parameters to be small. This result implies that the FGM may not contribute toward enhancing the fracture toughness of the TBCs considered here

  3. Developing High-Temperature Water-Soluble Coatings for Reconfigurable Tooling Materials-PREPRINT

    National Research Council Canada - National Science Library

    Calvert, George; Cao, Kevin J; Jacobson, Ted; Clements, Linda; Luo, Shen-Yi; Kim, Kwang J; O'Toole, Brendan

    2007-01-01

    .... This paper describes the development of such coatings, including the investigation of chemical modification and mechanical reinforcement as well as the suitability of the coatings in elevated-temperature use...

  4. Comparative Study of Micro- and Nano-structured Coatings for High-Temperature Oxidation in Steam Atmospheres

    OpenAIRE

    Pérez, F.J.; Castañeda, I.; Hierro, M.P.; Escobar Galindo, R.; Sánchez-López, J.C.; Mato, S.

    2014-01-01

    For many high-temperature applications, coatings are applied in order to protect structural materials against a wide range of different environments: oxidation, metal dusting, sulphidation, molten salts, steam, etc. The resistance achieved by the use of different kind of coatings, such as functionally graded material coatings, has been optimized with the latest designs. In the case of supercritical steam turbines, many attempts have been made in terms of micro-structural coatings design, main...

  5. Intermetallic and electrical insulator coatings on high-temperature alloys in liquid-lithium environments

    International Nuclear Information System (INIS)

    Park, J.H.

    1994-06-01

    In the design of liquid-metal cooling systems for fusion-reactor blanket, applications, the corrosion resistance of structural materials and the magnetohydrodynamic (MHD) force and its subsequent influence on thermal hydraulics and corrosion are major concerns. When the system is cooled by liquid metals, insulator coatings are required on piping surfaces in contact with the coolant. The objective of this study is to develop stable corrosion-resistant electrical insulator coatings at the liquid-metal/structural-material interface, with emphasis on electrically insulating coatings that prevent adverse MHD-generated currents from passing through the structural wall, and Be-V intermetallic coatings for first-wall components that face the plasma. Vanadium and V-base alloys are leading candidate materials for structural applications in a fusion reactor. Various intermetallic films were produced on V-alloys and on Types 304 and 316 stainless steel. The intermetallic layers were developed by exposure of the materials to liquid Li containing 2 at temperatures of 500--1030 degree C. CaO electrical insulator coatings were produced by reaction of the oxygen-rich layer with <5 at. % Ca dissolved in liquid Li at 400--700 degree C. The reaction converted the oxygen-rich layer to an electrically insulating film. This coating method is applicable to reactor components because the liquid metal can be used over and over; only the solute within the liquid metal is consumed. This paper will discuss initial results on the nature of the coatings and their in-situ electrical resistivity characteristics in liquid Li at high temperatures

  6. Some observations on the high temperature oxidation behaviour of plasma sprayed Ni3Al coatings

    International Nuclear Information System (INIS)

    Singh, H.; Prakash, S.; Puri, D.

    2007-01-01

    High temperature oxidation resistance of the superalloys can be greatly enhanced by plasma sprayed coatings and this is a growing industry of considerable economic importance. The purpose of these coatings is to form long-lasting oxidation protective scales. In the current investigation, Ni 3 Al powder was prepared by mechanical mixing of pure nickel and aluminium powders in a ball mill. Subsequently Ni 3 Al powder was deposited on three Ni-base superalloys: Superni 600, Superni 601 and Superni 718 and, one Fe-base superalloy, Superfer 800H by shrouded plasma spray process. Oxidation studies were conducted on the coated superalloys in air at 900 deg. C under cyclic conditions for 50 cycles. Each cycle consisted of 1 h heating followed by 20 min of cooling in air. The thermogravimetric technique was used to approximate the kinetics of oxidation. All the coated superalloys nearly followed parabolic rate law of oxidation. X-ray diffraction, SEM/EDAX and EPMA techniques were used to analyse the oxidation products. The Ni 3 Al coating was found to be successful in maintaining its adherence to the superalloy substrates in all the cases. The oxide scales formed on the oxidised coated superalloys were found to be intact and spallation-free. XRD analysis revealed the presence of phases like NiO, Al 2 O 3 and NiAl 2 O 4 in the oxide scales, which are reported as protective oxides against high temperature oxidation. The XRD results were further supported by SEM/EDAX and EPMA

  7. New experimental device for high-temperature normal spectral emissivity measurements of coatings

    International Nuclear Information System (INIS)

    Honnerová, Petra; Martan, Jiří; Kučera, Martin; Honner, Milan; Hameury, Jacques

    2014-01-01

    A new experimental device for normal spectral emissivity measurements of coatings in the infrared spectral range from 1.38 μm to 26 μm and in the temperature range from 550 K to 1250 K is presented. A Fourier transform infrared spectrometer (FTIR) is used for the detection of sample and blackbody spectral radiation. Sample heating is achieved by a fiber laser with a scanning head. Surface temperature is measured by two methods. The first method uses an infrared camera and a reference coating with known effective emissivity, the second method is based on the combination of Christiansen wavelength with contact and noncontact surface temperature measurement. Application of the method is shown on the example of a high-temperature high-emissivity coating. Experimental results obtained with this apparatus are compared with the results performed by a direct method of Laboratoire National d’Essais (LNE) in France. The differences in the spectra are analyzed. (paper)

  8. High Temperature Multilayer Environmental Barrier Coatings Deposited Via Plasma Spray-Physical Vapor Deposition

    Science.gov (United States)

    Harder, Bryan James; Zhu, Dongming; Schmitt, Michael P.; Wolfe, Douglas E.

    2014-01-01

    Si-based ceramic matrix composites (CMCs) require environmental barrier coatings (EBCs) in combustion environments to avoid rapid material loss. Candidate EBC materials have use temperatures only marginally above current technology, but the addition of a columnar oxide topcoat can substantially increase the durability. Plasma Spray-Physical Vapor Deposition (PS-PVD) allows application of these multilayer EBCs in a single process. The PS-PVD technique is a unique method that combines conventional thermal spray and vapor phase methods, allowing for tailoring of thin, dense layers or columnar microstructures by varying deposition conditions. Multilayer coatings were deposited on CMC specimens and assessed for durability under high heat flux and load. Coated samples with surface temperatures ranging from 2400-2700F and 10 ksi loads using the high heat flux laser rigs at NASA Glenn. Coating morphology was characterized in the as-sprayed condition and after thermomechanical loading using electron microscopy and the phase structure was tracked using X-ray diffraction.

  9. High temperature oxidation behaviour of mullite coated C/C composites in air

    International Nuclear Information System (INIS)

    Fritze, H.; Borchardt, G.; Weber, S.; Scherrer, S.; Weiss, R.

    1997-01-01

    Based on thermogravimetric measurements on Si-SiC-mullite coated C/C material the temperature dependence of the overall rate constant is interpreted in the temperature range 400 C 1400 C), however, the oxidation behaviour of SiC limits long term application. In this temperature range, additional outer mullite coatings produced by pulsed laser deposition improve the oxidation behaviour. (orig.)

  10. Development of coating technology for nuclear fuel by self-propagating high temperature synthesis

    International Nuclear Information System (INIS)

    Choi, Y.; Kim, Bong G.; Lee, Y. W.

    1997-01-01

    This paper presents experimental results of the preparation of silicon carbide and graphite layers on a nuclear fuel from silane and propane gases by a conventional chemical vapor deposition and combustion synthesis technologies. The direct reaction between silicon and pyrolytic carbon in a high temperature releases sufficient amount of energy to make a synthesis self-sustaining under the preheating of about 1200 deg C. During this high temperature process, lamellar structure with isotropic carbon synthesis. A full characterization of phase composition and final morphology of the coated layers by X-ray diffraction, SEM and AES is presented. (author). 6 refs., 1 tab., 11 figs

  11. High-Temperature Oxidation and Smelt Deposit Corrosion of Ni-Cr-Ti Arc-Sprayed Coatings

    Science.gov (United States)

    Matthews, S.; Schweizer, M.

    2013-08-01

    High Cr content Ni-Cr-Ti arc-sprayed coatings have been extensively applied to mitigate corrosion in black liquor recovery boilers in the pulp and paper industry. In a previous article, the effects of key spray parameters on the coating's microstructure and its composition were investigated. Three coating microstructures were selected from that previous study to produce a dense, oxidized coating (coating A), a porous, low oxide content coating (coating B), and an optimized coating (coating C) for corrosion testing. Isothermal oxidation trials were performed in air at 550 and 900 °C for 30 days. Additional trials were performed under industrial smelt deposits at 400 and 800 °C for 30 days. The effect of the variation in coating microstructure on the oxidation and smelt's corrosion response was investigated through the characterization of the surface corrosion products, and the internal coating microstructural developments with time at high temperature. The effect of long-term, high-temperature exposure on the interaction between the coating and substrate was characterized, and the mechanism of interdiffusion was discussed.

  12. Computer simulation of the optical properties of high-temperature cermet solar selective coatings

    Energy Technology Data Exchange (ETDEWEB)

    Nejati, M. Reza [K.N. Toosi Univ. of Technology, Dept. of Mechanical Engineering, Tehran (Iran); Fathollahi, V.; Asadi, M. Khalaji [AEOI, Center for Renewable Energy Research and Applications (CRERA), Tehran (Iran)

    2005-02-01

    A computer simulation is developed to calculate the solar absorptance and thermal emittance of various configurations of cermet solar selective coatings. Special attention has been paid to those material combinations, which are commonly used in high-temperature solar thermal applications. Moreover, other material combinations such as two-, three- and four-cermet-layer structures as solar selective coatings have been theoretically analyzed by computer simulation using three distinct physical models of Ping Sheng, Maxwell-Garnett and Bruggeman. The novel case of two-cermet-layer structure with different cermet components has also been investigated. The results were optimized by allowing the program to manipulate the metal volume fraction and thickness of each layer and the results compared to choose the best possible configuration. The calculated results are within the range of 0.91-0.97 for solar absorptance and 0.02-0.07 for thermal emittance at room temperature. (Author)

  13. Ultra High Temperature and Multifunctional Ceramic Matrix Composite – Coating Systems for Light-Weight Space and Aero Systems

    Data.gov (United States)

    National Aeronautics and Space Administration — Revolutionary ultra-high temperature, high mechanical loading capable, oxidation resistant, durable ceramic coatings and light-weight fiber-reinforced Ceramic Matrix...

  14. Microstructure Based Material-Sand Particulate Interactions and Assessment of Coatings for High Temperature Turbine Blades

    Science.gov (United States)

    Murugan, Muthuvel; Ghoshal, Anindya; Walock, Michael; Nieto, Andy; Bravo, Luis; Barnett, Blake; Pepi, Marc; Swab, Jeffrey; Pegg, Robert Tyler; Rowe, Chris; hide

    2017-01-01

    Gas turbine engines for military/commercial fixed-wing and rotary wing aircraft use thermal barrier coatings in the high-temperature sections of the engine for improved efficiency and power. The desire to further make improvements in gas turbine engine efficiency and high power-density is driving the research and development of thermal barrier coatings and the effort of improving their tolerance to fine foreign particulates that may be contained in the intake air. Both commercial and military aircraft engines often are required to operate over sandy regions such as in the Middle-East nations, as well as over volcanic zones. For rotorcraft gas turbine engines, the sand ingestion is adverse during take-off, hovering near ground, and landing conditions. Although, most of the rotorcraft gas turbine engines are fitted with inlet particle separators, they are not 100 percent efficient in filtering fine sand particles of size 75 microns or below. The presence of these fine solid particles in the working fluid medium has an adverse effect on the durability of turbine blade thermal barrier coatings and overall performance of the engine. Typical turbine blade damages include blade coating wear, sand glazing, Calcia-Magnesia-Alumina-Silicate (CMAS) attack, oxidation, plugged cooling holes, all of which can cause rapid performance deterioration including loss of aircraft. The objective of this research is to understand the fine particle interactions with typical ceramic coatings of turbine blades at the microstructure level. A finite-element based microstructure modeling and analysis has been performed to investigate particle-surface interactions, and restitution characteristics. Experimentally, a set of tailored thermal barrier coatings and surface treatments were down-selected through hot burner rig tests and then applied to first stage nozzle vanes of the Gas Generator Turbine of a typical rotorcraft gas turbine engine. Laser Doppler velocity measurements were performed

  15. High-Temperature Tolerance in Multi-Scale Cermet Solar-Selective Absorbing Coatings Prepared by Laser Cladding.

    Science.gov (United States)

    Pang, Xuming; Wei, Qian; Zhou, Jianxin; Ma, Huiyang

    2018-06-19

    In order to achieve cermet-based solar absorber coatings with long-term thermal stability at high temperatures, a novel single-layer, multi-scale TiC-Ni/Mo cermet coating was first prepared using laser cladding technology in atmosphere. The results show that the optical properties of the cermet coatings using laser cladding were much better than the preplaced coating. In addition, the thermal stability of the optical properties for the laser cladding coating were excellent after annealing at 650 °C for 200 h. The solar absorptance and thermal emittance of multi-scale cermet coating were 85% and 4.7% at 650 °C. The results show that multi-scale cermet materials are more suitable for solar-selective absorbing coating. In addition, laser cladding is a new technology that can be used for the preparation of spectrally-selective coatings.

  16. High-Temperature Tolerance in Multi-Scale Cermet Solar-Selective Absorbing Coatings Prepared by Laser Cladding

    Directory of Open Access Journals (Sweden)

    Xuming Pang

    2018-06-01

    Full Text Available In order to achieve cermet-based solar absorber coatings with long-term thermal stability at high temperatures, a novel single-layer, multi-scale TiC-Ni/Mo cermet coating was first prepared using laser cladding technology in atmosphere. The results show that the optical properties of the cermet coatings using laser cladding were much better than the preplaced coating. In addition, the thermal stability of the optical properties for the laser cladding coating were excellent after annealing at 650 °C for 200 h. The solar absorptance and thermal emittance of multi-scale cermet coating were 85% and 4.7% at 650 °C. The results show that multi-scale cermet materials are more suitable for solar-selective absorbing coating. In addition, laser cladding is a new technology that can be used for the preparation of spectrally-selective coatings.

  17. Study on Modified Water Glass Used in High Temperature Protective Glass Coating for Ti-6Al-4V Titanium Alloy

    Directory of Open Access Journals (Sweden)

    Shuang Yang

    2018-04-01

    Full Text Available Sodium silicate water glass was modified with sodium polyacrylate as the binder, the composite slurry used for high-temperature oxidation-resistant coating was prepared by mixing glass powder with good lubrication properties in the binder. The properties of the modified binder and high-temperature oxidation resistance of Ti-6Al-4V titanium alloy coated with composite glass coating were studied by XRD, SEM, EDS, TG-DSC and so on. Results showed that sodium polyacrylate modified water glass could obviously improve the suspension stability of the binder, the pyrolytic carbon in the binder at high temperature could increase the surface tension in the molten glass system, and the composite glass coating could be smooth and dense after heating. Pyrolytic carbon diffused and combined with oxygen in the coating under the heating process to protect the titanium alloy from oxidation. The thickness of the oxide layer was reduced 51% after applying the high-temperature oxidation-resistant coating. The coating also showed a nearly 30% reduction in friction coefficient due to the boundary lubricant regime. During cooling, the coating could be peeled off easily because of the mismatched CTE between the coating and substrate.

  18. Influence of coating on nanocrystalline magnetic properties during high temperature thermal ageing

    Energy Technology Data Exchange (ETDEWEB)

    Lekdim, Atef, E-mail: atef.lekdim@univ-lyon1.fr; Morel, Laurent; Raulet, Marie-Ange

    2017-05-15

    Since their birth or mergence the late 1980s, the nanocrystalline ultrasoft magnetic materials are taking a great importance in power electronic systems conception. One of the main advantages that make them more attractive nowadays is their ability to be packaged since the reduction of the magnetostrictive constant to almost zero. In aircraft applications, due to the high component compactness and to their location (for example near the jet engine), the operating temperature increases and may reach easily 200 °C and more. Consequently, the magnetic thermal ageing may occur but is, unfortunately, weakly studied. This paper focuses on the influence of the coating (packaging type) on the magnetic nanocrystalline performances during a thermal ageing. This study is based on monitoring the magnetic characteristics of two types of nanocrystalline cores (naked and coated) during a thermal activated ageing (100, 150 and 200 °C). Based on a dedicated monitoring protocol, a large magnetic characterization has been done and analyzed. Elsewhere, X-Ray Diffraction and magnetostriction measurements were carried out to support the study of the anisotropy energies evolution with ageing. This latter is discussed in this paper to explain and give hypothesis about the ageing phenomena. - Highlights: • The coating impacts drastically the magnetic properties during thermal ageing. • Irreversible ageing phenomena after the total coating breakage. • The deteriorations are related to the storage of the magnetoelastic anisotropy.

  19. Preliminary study of HDA coating on CLAM steel followed by high temperature oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaoqiang, E-mail: newboy.chen@163.com; Huang, Qunying; Yan, Zilin; Song, Yong; Liu, Shaojun; Jiang, Zhizhong

    2013-11-15

    A hot-dip aluminizing process is expected to produce aluminide coatings on structural materials to resist tritium permeation, corrosion, and magnetohydrodynamic (MHD) effects in the fusion reactor blanket. China Low Activation Martensitic (CLAM) steel, which is the candidate structural material for the LiPb blanket system in China, was coated with pure aluminum and with an Al–Si alloy. Factors affecting the thickness and morphology of the aluminide coatings were studied. After the hot-dipping treatment, FeAl{sub 3} and Fe{sub 2}Al{sub 5} were observed at the Al/steel interface. The existence of silicon in the molten aluminum suppressed the growth of Fe{sub 2}Al{sub 5}, built up the thickness of FeAl{sub 3} slightly, and contributed to reducing the thickness of the intermetallic layer. The brittle phase of Fe{sub 2}Al{sub 5} had completely transformed to ductile phases of FeAl{sub 2}, FeAl and α-Fe(Al) after high temperature heat-treatment in air. Kirkendall voids were found in the diffusion layer, due to the rapid interdiffusion of iron and aluminum during oxidation. Cracks and pores were observed on the coating surface and at the interlayer. Grazing incidence X-ray diffraction indicates the presence of α-Al{sub 2}O{sub 3} in the oxide layer.

  20. Role of oxides and porosity on high temperature oxidation of liquid fuelled HVOF thermal sprayed Ni50Cr coatings

    OpenAIRE

    Song, B.; Bai, M.; Voisey, K.T.; Hussain, Tanvir

    2017-01-01

    High chromium content in Ni50Cr thermally sprayed coatings can generate a dense and protective scale at the surface of coating. Thus, the Ni50Cr coating is widely used in high temperature oxidation and corrosion applications. A commercially available gas atomized Ni50Cr powder was sprayed onto a power plant steel (ASME P92) using a liquid fuelled high velocity oxy-fuel (HVOF) thermal spray with three processing parameters in this study. Microstructure of as-sprayed coatings was examined using...

  1. Improved oxidation resistance of ferritic steels with LSM coating for high temperature electrochemical applications

    DEFF Research Database (Denmark)

    Palcut, Marián; Mikkelsen, Lars; Neufeld, Kai

    2012-01-01

    The effect of single layer La0.85Sr0.15MnO3−δ (LSM) coatings on high temperature oxidation behaviour of four commercial chromia-forming steels, Crofer 22 APU, Crofer 22 H, E-Brite and AL 29-4C, is studied. The samples were oxidized for 140–1000 h at 1123 K in flowing simulated ambient air (air + 1......% H2O) and oxygen and corrosion kinetics monitored by mass increase of the materials over time. The oxide scale microstructure and chemical composition are investigated by scanning electron microscopy/energy-dispersive spectroscopy. The kinetic data obey a parabolic rate law. The results show...... that the LSM coating acts as an oxygen transport barrier that can significantly reduce the corrosion rate....

  2. High temperature tribological behaviour of carbon based (B{sub 4}C and DLC) coatings in sliding contact with aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Gharam, A. Abou, E-mail: abougha@uwindsor.c [Mechanical Automotive and Materials Engineering Department, University of Windsor, Windsor, ON, N9B3P4 (Canada); Lukitsch, M.J.; Balogh, M.P. [Chemical Sciences and Materials Systems Laboratory, General Motors R and D Center, 30500 Mound Road, Warren, MI 48090-9055 (United States); Alpas, A.T. [Mechanical Automotive and Materials Engineering Department, University of Windsor, Windsor, ON, N9B3P4 (Canada)

    2010-12-30

    Carbon based coatings, particularly diamond-like carbon (DLC) films are known to resist aluminum adhesion and reduce friction at room temperature. This attractive tribological behaviour is useful for applications such as tool coatings used for aluminum forming and machining. However, for those operations that are performed at elevated temperatures (e.g. hot forming) or that generate frictional heat during contact (e.g. dry machining) the suitable coatings are required to maintain their tribological properties at high temperatures. Candidates for these demanding applications include boron carbide (B{sub 4}C) and DLC coatings. An understanding of the mechanisms of friction, wear and adhesion of carbon based coatings against aluminum alloys at high temperatures will help in designing coatings with improved high temperature tribological properties. With this goal in mind, this study focused on B{sub 4}C and a hydrogenated DLC coatings sliding against a 319 grade cast aluminum alloy by performing pin-on-disk experiments at temperatures up to 400 {sup o}C. Experimental results have shown that the 319 Al/B{sub 4}C tribosystem generated coefficient of friction (COF) values ranging between 0.42 and 0.65, in this temperature range. However, increased amounts of aluminum adhesion were detected in the B{sub 4}C wear tracks at elevated temperatures. Focused ion beam (FIB) milled cross sections of the wear tracks revealed that the coating failed due to shearing along the columnar grain boundaries of the coating. The 319 Al/DLC tribosystem maintained a low COF (0.15-0.06) from room temperature up to 200 {sup o}C. This was followed by an abrupt increase to 0.6 at 400 {sup o}C. The deterioration of friction behaviour at T > 200 {sup o}C was attributed to the exhaustion of hydrogen and hydroxyl passivants on the carbon transfer layer formed on the Al pin.

  3. Development of advanced fabrication technology for high-temperature gas-cooled reactor fuel. Reduction of coating failure fraction

    International Nuclear Information System (INIS)

    Minato, Kazuo; Kikuchi, Hironobu; Fukuda, Kousaku; Tobita, Tsutomu; Yoshimuta, Sigeharu; Suzuki, Nobuyuki; Tomimoto, Hiroshi; Nishimura, Kazuhisa; Oda, Takafumi

    1998-11-01

    The advanced fabrication technology for high-temperature gas-cooled reactor fuel has been developed to reduce the coating failure fraction of the fuel particles, which leads to an improvement of the reactor safety. The present report reviews the results of the relevant work. The mechanisms of the coating failure of the fuel particles during coating and compaction processes of the fuel fabrication were studied to determine a way to reduce the coating failure fraction of the fuel. The coating process was improved by optimizing the mode of the particle fluidization and by developing the process without unloading and loading of the particles at intermediate coating process. The compaction process was improved by optimizing the combination of the pressing temperature and the pressing speed of the overcoated particles. Through these modifications of the fabrication process, the quality of the fuel was improved outstandingly. (author)

  4. Adhesion property and high-temperature oxidation behavior of Cr-coated Zircaloy-4 cladding tube prepared by 3D laser coating

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun-Gil, E-mail: hgkim@kaeri.re.kr; Kim, Il-Hyun; Jung, Yang-Il; Park, Dong-Jun; Park, Jeong-Yong; Koo, Yang-Hyun

    2015-10-15

    A 3D laser coating technology using Cr powder was developed for Zr-based alloys considering parameters such as: the laser beam power, inert gas flow, cooling of Zr-based alloys, and Cr powder control. This technology was then applied to Zr cladding tube samples to study the effect of Cr coating on the high-temperature oxidation of Zr-based alloys in a steam environment of 1200 °C for 2000s. It was revealed that the oxide layer thickness formed on the Cr-coated tube surface was about 25-times lower than that formed on a Zircaloy-4 tube surface. In addition, both the ring compression and the tensile tests were performed to evaluate the adhesion properties of the Cr-coated sample. Although some cracks were formed on the Cr-coated layer, the Cr-coated layer had not peeled off after the two tests.

  5. Evaluation of anti-scale property of CrN coatings at high temperature and high pressure

    International Nuclear Information System (INIS)

    Honda, Tomomi; Iwai, Yoshiro; Uno, Ryoji; Yoshinaga, Shigeki

    2007-01-01

    It is well known that oxide scale which adheres to the inner wall of the nozzle in nuclear power plant causes a serious problem. This study was carried out to obtain the knowledge about initiation and deposition behavior of oxide scale on the surface of SUS304 stainless steel and the evaluation of anti-scale property of chromium nitride (CrN) coatings at high temperature and high pressure. SUS304 stainless steel and CrN coating specimens were heated in water up to 200degC for more than 250 hours. Obtained results are summarized as follows. Initiation of the scale started from corrosive part of SUS304 stainless steel and the scale grows by deposition of magnetite particles. CrN coating can be applied to prevent the initiation and deposition of oxide scale. (author)

  6. High Temperature Sliding Wear of NiAl-based Coatings Reinforced by Borides

    Directory of Open Access Journals (Sweden)

    Oleksandr UMANSKYI

    2016-05-01

    Full Text Available The development of composite materials (CM in the systems “metal-refractory compound” is one of the up-to-date trends in design of novel materials aimed at operating under the conditions of significant loads at high temperature. To design such material, NiAl, which is widely used for deposition of protective coatings on parts of gas-turbine engines, was selected for a matrix. To strengthen a NiAl under the conditions of intense wear and a broad temperature range (up to 1000 °C, it is reasonable to add refractory inclusions. Introduction of refractory borides into matrix leads to a marked increase in metal wear resistance. In order to research the behavior of the designed composites at high temperatures and to study the influence of oxides on the friction processes, the authors carried out high temperature oxidation of CM of the above systems at 1000 °С for 90 min. It was determined that all of the composites were oxidized selectively and that the thickness of oxide layers formed on the boride inclusions is 3 – 7 times that on the oxides formed on the NiAl matrix. The mechanism of wear of gas-thermal coatings of the NiAl – МеB2 systems was studied for conditions of high temperature tribotests using the «pin-on-disc» technique. The obtained results indicate that introduction of TiB2, CrB2 and ZrB2 leads to their more intense oxidation during high temperature tribotests as compared to the matrix. The oxides formed on refractory borides act as solid lubricants, which promote a decrease in wear of the contact friction pairs. For more detailed investigation of the effect of tribo-oxidation products on the friction processes, tribotests were conducted for prior oxidized (at 900 °С coatings NiAl – 15 wt.% CrB2 (TiB2, ZrB2.DOI: http://dx.doi.org/10.5755/j01.ms.22.1.8093

  7. Materials for coatings against erosion, fretting, and high-temperature oxidation

    International Nuclear Information System (INIS)

    Feller, H.G.; Wienstroth, U.; Balke, C.

    1990-01-01

    This paper investigates the applicability of Co-Cr-W alloys (CoCr29W29, CoCr29W9Y1, CoCr29W9Fe3Y1, CoCr29W9Y1Al1) as coating materials for the substrates MA 6000 and MA 754. Their properties are compared with those of Amperit 410, which is the alloy NiCo23Cr17Al12.5Y0.5. Their isothermal oxidation behaviour at temperatures up to 1000deg C is found to be better for the most part than that of the commercially available Amperit 410. Furthermore, the oxide shows distinctly better adhesion, so that better results concerning resistance to hot-gas corrosion are expected. The fretting behaviour at room temperature is characterized by very low friction factors and a strong resistance to wear. A comparable behaviour is found for resistance to erosive wear. Specimens tested for 500 hours in the pressurised beam device exhibit only minimal changes of mass in the bond MA 600/coating. Single-particle impact tests reveal that exposure of specimens to high temperatures leads to an increase in mean hardness, which is caused by a solidification of the yttrium-containing phase. (orig./MM) [de

  8. EFFECT OF La2O3 ON HIGH-TEMPERATURE OXIDATION RESISTANCE OF ELECTROSPARK DEPOSITED Ni-BASED COATINGS

    OpenAIRE

    YUXIN GAO; JIAN YI; ZHIGANG FANG; HU CHENG

    2014-01-01

    The oxidation tests of electrospark deposited Ni-based coatings without and with 2.5 wt.% La2O3 were conducted at 960°C in air for 100 h. The oxidation kinetic of the coatings was studied by testing the weight gain. The phase structures and morphologies of the oxidized coatings were investigated by XRD and SEM. The experimental results show that the coatings with 2.5 wt.% La2O3 exhibits excellent high-temperature oxidation resistance including low oxidation rate and improved spallation resist...

  9. Development of advanced metallic coatings resistant to corrosion in high temperature industrial atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Weber, T.; Bender, R.; Rosado, C.; Schuetze, M. [DECHEMA e.V., Frankfurt am Main (Germany)

    2004-07-01

    Following the experimental results that {gamma}-TiAl is highly resistant in reducing sulfidizing atmospheres the development of Ti-Al-co-diffusion coatings produced in a single step pack cementation process was started. The appropriate diffusion powder compositions were selected using thermodynamical calculations. Different Al-Ti-, Al-Si- and Al-Ti-Si-diffusion coatings were successfully applied on austenitic steels as well as Ni-base materials and showed excellent behaviour in reducing sulfidizing atmospheres with high carbon contents (CH{sub 4} - 1% CO - 1% CO{sub 2} - 10% H{sub 2} - 7% H{sub 2}S) up to 700 deg. C, under metal dusting conditions (H{sub 2} - 25 CO - 2% H{sub 2}O and CO - 2.4% CO{sub 2} - 1% CH{sub 4} - 9.4% N{sub 2} - 23.4% H{sub 2} - 0.2% H{sub 2}O - 1 ppm H{sub 2}S-0.3 ppm HCl) at temperatures of 620 deg. C and 700 deg. C. The application of diffusion coatings on ferritic materials has to be modified due to the specific requirements on the mechanical properties which are affected by the heat treatment during the diffusion process. TiAl was also applied by the HVOF thermal spray method on ferritic steels. Due to similarity of the thermal expansion coefficients this substrate-coating system proved to be mechanically very stable also under thermal cycling conditions. (authors)

  10. Quality control of coated fuel particles for high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Kaneko, Mitsunobu

    1987-01-01

    The quality control of the coated fuel particles for high temperature gas-cooled reactors is characterized by the fact that the size of the target product to be controlled is very small, and the quantity is very large. Accordingly, the sampling plan and the method of evaluating the population through satisfically treating the measured data of the samples are the important subjects to see and evaluate the quality of a batch or a lot. This paper shows the fabrication process and the quality control procedure for the coated fuel particles. The development work of a HTGR was started by Japan Atomic Energy Research Institute in 1969, and as for the production technology for coated fuel particles, Nuclear Fuel Industries, Ltd. has continued the development work. The pilot plan with the capacity of about 40 kg/year was established in 1972. The fuel product fabricated in this plant was put to the irradiation experiment and out-of-pile evaluation test. In 1983, the production capacity was expanded to 200 kg/year, and the fuel compacts for the VHTRC in JAERI were produced for two years. The basic fuel design, the fabrication process, the quality control, the process control and the quality assurance are reported. For the commercial product, the studies from the viewpoint of production and quality control costs are required. (Kako, I.)

  11. High temperature oxidation resistance of magnetron-sputtered homogeneous CrAlON coatings on 430 steel

    Energy Technology Data Exchange (ETDEWEB)

    Garratt, E; Wickey, K J; Nandasiri, M I; Moore, A; AlFaify, S; Gao, X [Department of Physics, Western Michigan University, Kalamazoo, MI 49008 (United States); Smith, R J; Buchanan, T L; Priyantha, W; Kopczyk, M; Gannon, P E [Montana State University, Bozeman, MT, 59717 (United States); Kayani, A, E-mail: asghar.kayani@wmich.ed

    2009-11-01

    The requirements of low cost and high-temperature corrosion resistance for bipolar interconnect plates in solid oxide fuel cell stacks has directed attention to the use of metal plates with oxidation resistant coatings. We have investigated the performance of steel plates with homogenous coatings of CrAlON (oxynitrides). The coatings were deposited using RF magnetron sputtering, with Ar as a sputtering gas. Oxygen in these coatings was not intentionally added. Oxygen might have come through contaminated nitrogen gas bottle, leak in the chamber or from the partial pressure of water vapors. Nitrogen was added during the growth process to get oxynitride coating. The Cr/Al composition ratio in the coatings was varied in a combinatorial approach. The coatings were subsequently annealed in air for up to 25 hours at 800 {sup o}C. The composition of the coated plates and the rate of oxidation were characterized using Rutherford backscattering (RBS) and nuclear reaction analysis (NRA). Surface characterization was carried out using Atomic Force Microscopy (AFM) and surfaces of the coatings were found smooth on submicron scale. From our results, we conclude that Al rich coatings are more susceptible to oxidation than Cr rich coatings.

  12. Evaluating the Properties of High-Temperature and Low-Temperature Wear of TiN Coatings Deposited at Different Temperatures

    Directory of Open Access Journals (Sweden)

    B. Khorrami Mokhori

    2017-02-01

    Full Text Available In this research titanium nitride (TiN films were prepared by plasma assisted chemical vapor deposition using TiCl4, H2, N2 and Ar on the AISI H13 tool steel. Coatings were deposited during different substrate temperatures (460°C, 480 ° C  and 510 °C. Wear tests were performed in order to study the acting wear mechanisms in the high(400 °C and low (25 °C temperatures by ball on disc method. Coating structure and chemical composition were characterized using scanning electron microscopy, microhardness and X-ray diffraction. Wear test result was described in ambient temprature according to wear rate. It was evidenced that the TiN coating deposited at 460 °C has the least weight loss with the highest hardness value. The best wear resistance was related to the coating with the highest hardness (1800 Vickers. Wear mechanisms were observed to change by changing wear temperatures. The result of wear track indicated that low-temprature wear has surface fatigue but high-temperature wear showed adhesive mechanism.

  13. Comparative examination of the microstructure and high temperature oxidation performance of NiCrBSi flame sprayed and pack cementation coatings

    Science.gov (United States)

    Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Skolianos, S.; Chrissafis, K.; Stergioudis, G.

    2009-01-01

    Coatings formed from NiCrBSi powder were deposited by thermal spray and pack cementation processes on low carbon steel. The microstructure and morphology of the coatings were studied by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Flame sprayed coatings exhibited high porosity and were mechanically bonded to the substrate while pack cementation coatings were more compact and chemically bonded to the substrate. The microhardness and the high temperature oxidation resistance of the coated samples were evaluated by a Vickers microhardness tester and by thermogravimetric measurements (TG), respectively. Pack cementation coatings showed higher hardness and were more protective to high temperature environments than the flame sprayed coatings.

  14. Nanostructured Coatings with Self-Healing and Temperature Homogenization Functions for High Temperature Sliding Interfaces

    Science.gov (United States)

    2010-10-01

    showing the stainless steel chamber (A), the rotatable substrate holder (B), the plasma burning between substrate holder and magnetrons (C) and three...Final Report University of Leoben, Austria 3 The sputtering system consists of a cylindrical stainless steel chamber (Ø 380 x 235mm) (A) which...Si (100), AISI M2 steel and Fe substrates. The tribological performance of these coatings has been compared to undoped ZrO2 thin films in a

  15. High temperature tribological performance of CrAlYN/CrN nanoscale multilayer coatings deposited on ?-TiAl

    OpenAIRE

    Walker, J.C.; Ross, I.M.; Reinhard, C.; Rainforth, W.M.; Hovsepian, P.Eh.

    2009-01-01

    This paper details the effect of temperature on the frictional behaviour of highly novel CrAlYN/CrN multilayer coatings, deposited by High Power Impulse Magnetron Sputtering (HIPIMS) on a Titanium Aluminide alloy used as fan blade material in the aerospace and a turbo-charger wheel in the automotive industries. The work was the first to discover the high temperature oxide 'glaze' layer formation which occurred on CrN multilayer-type coatings at higher temperatures and has received significant...

  16. Preparation of high critical temperature YBa2Cu3O7 superconducting coatings by thermal spray

    International Nuclear Information System (INIS)

    Lacombe, Jacques

    1991-01-01

    The objective of this research thesis is the elaboration of YBa 2 Cu 3 O 7 superconducting coatings by thermal spray. These coatings must have a high adherence, a high cohesion, and the best possible electrical characteristics. The author first briefly presents physical-chemical characteristics of this ceramic, and proposes a bibliographical synthesis on thick coatings prepared by thermal spray. In the next parts, he studies and describes conditions of elaboration of poly-granular coatings of YBa 2 Cu 3 O 7 , and their structural and electric characteristics [fr

  17. Role of high-temperature creep stress in thermally grown oxide growth of thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, K.; Nakao, Y.; Seo, D.; Miura, H.; Shoji, T. [Tohoku Univ., Sendai (Japan)

    2008-07-01

    Thermally grown oxide (TGO) grows at the top / bond coating interface of the thermal barrier coating (TBC) in service. It is supposed that the failures of the TBC occur due to thermal stress and the decrease of adhesive strength caused by the TGO growth. Recently, large local stress has been found to change both the diffusion constant of oxygen through an existing oxide and the rate of chemical reaction at the oxide / oxidized material interface. Since high thermal stress occurs in the TBC, the volume expansion of the newly grown oxide, and centrifugal force, the growth rate of the TGO may change depending on not only temperature but also the stress. The aim of this study is to make clear the influence of stress on the growth rate of the TGO quantitatively. As a result, the thickness of the TGO clearly increases with increase of the amplitude of the applied stress and temperature. The increase rate of the TGO thickness is approximately 23% when the applied stress is increased from 0 to 205 MPa at 900 C, and approximately 29% when the stress is increased from 0 to 150 MPa at 950 C. (orig.)

  18. An Integrated Study of a Novel Thermal Coating for Nb-Based High Temperature Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shizhong [Southern Univ. and A & M College, Baton Rouge, LA (United States)

    2015-01-31

    This report summarizes our recent works of ab initio density functional theory (DFT) method and molecular dynamics (MD) simulation on the interfaces between niobium substrate and coatings at atomic level. Potential oxidation barrier bond coat, Nb₂AlC and high entropy alloys, and top coat candidates were synthesized, characterized, and evaluated in our labs. The simulation methods, experimental validation techniques, achievements already reached, students and postdoc training, and future improvement are briefly introduced.

  19. Corrosion resistance of Fe-Al alloy-coated steel under bending stress in high temperature lead-bismuth eutectic

    International Nuclear Information System (INIS)

    Yamaki, Eriko; Takahashi, Minoru

    2009-01-01

    Formation of thin Fe-Al alloy layers on the surface of cladding and structural materials is effective to protect a base material from corrosion in high temperature LBE. However, it is concerned that these protective layers may be damaged under various stress conditions. This study on Fe-Al alloy coatings deposited by unbalanced magnetron sputtering (UBMS) is focused to evaluate corrosion resistance and integrity of the Fe-Al coating layers with thickness of 0.5 mm under bending stress in high temperature LBE. High chromium steel specimens (HCM12A, Recloy10) with Fe-Al alloy coating were exposed to LBE pool with low oxygen concentration (up to 5.2x10 -8 wt%) at 550 and 650degC under 45kg-loading for 240 and 500 h. No LBE corrosion was observed in the base metal and coating layer after the tests at 550degC for 550 h. The coating layers could be barrier for corrosion resistance from LBE at 550degC, although the coating scales are cracked by the load. At 650degC, because the base metal was contoccured directly with LBE through cracks across the coating layer. Penetration of LBE to base metal and dissolution of beset metal into LBE occurred. Fe-Al coating layer was not corroded by LBE. (author)

  20. Characterisation of Ceramic-Coated 316LN Stainless Steel Exposed to High-Temperature Thermite Melt and Molten Sodium

    Science.gov (United States)

    Ravi Shankar, A.; Vetrivendan, E.; Shukla, Prabhat Kumar; Das, Sanjay Kumar; Hemanth Rao, E.; Murthy, S. S.; Lydia, G.; Nashine, B. K.; Mallika, C.; Selvaraj, P.; Kamachi Mudali, U.

    2017-11-01

    Currently, stainless steel grade 316LN is the material of construction widely used for core catcher of sodium-cooled fast reactors. Design philosophy for core catcher demands its capability to withstand corium loading from whole core melt accidents. Towards this, two ceramic coatings were investigated for its application as a layer of sacrificial material on the top of core catcher to enhance its capability. Plasma-sprayed thermal barrier layer of alumina and partially stabilised zirconia (PSZ) with an intermediate bond coat of NiCrAlY are selected as candidate material and deposited over 316LN SS substrates and were tested for their suitability as thermal barrier layer for core catcher. Coated specimens were exposed to high-temperature thermite melt to simulate impingement of molten corium. Sodium compatibility of alumina and PSZ coatings were also investigated by exposing samples to molten sodium at 400 °C for 500 h. The surface morphology of high-temperature thermite melt-exposed samples and sodium-exposed samples was examined using scanning electron microscope. Phase identification of the exposed samples was carried out by x-ray diffraction technique. Observation from sodium exposure tests indicated that alumina coating offers better protection compared to PSZ coating. However, PSZ coating provided better protection against high-temperature melt exposure, as confirmed during thermite melt exposure test.

  1. Enhanced high temperature performance of LiMn2O4 coated with ...

    Indian Academy of Sciences (India)

    Cathode material, LiMn2O4, was synthesized by solid-state reaction followed by surface coating of. Li3BO3 solid ... date material for lithium ion battery due to its high voltage, ... coating of LiMn2O4 with various protective layers as Cr2O3.

  2. Examples illustrating the effects of high-temperature corrosion and protective coatings on the creep-to-rupture behaviour of materials resistant to very high temperatures

    International Nuclear Information System (INIS)

    Sachova, E.; Hougardy, H.P.; Granacher, J.

    1989-01-01

    Assessing the creep stress, it is assumed in general that the sub-surface effects in a specimen correspond to those at the surface. Particularly in very high temperature environments, however, oxidation is an additional effect to be taken into account, and there are other operational stresses to be reckoned with, as e.g. hot gas corrosion of gas turbine blades. The reduction of the effective cross section due to corrosion for instance of the material affected by long-term creep leads to an increase in stresses and thus shortens the period up to rupture. Protective coatings will prevent or at least delay corrosion. The paper reports the performance of various protective coatings. Pt-Al coatings have have been found to remain intact even on specimens with the longest testing periods up to rupture, to an extent that there was no oxidation at the grain boundaries proceeding from the surface to the sub-surface material. The same applies to the plasma-sprayed coatings, although in some cases pores had developed in the coating. The chromium alitizations were used up irregularly over the surface of some specimens tested at 1000deg C. Chromizing layers have been found to be more strongly damaged than the other coatings tested under comparable conditions. (orig./RHM) [de

  3. Synthesis and analysis of Mo-Si-B based coatings for high temperature oxidation protection of ceramic materials

    Science.gov (United States)

    Ritt, Patrick J.

    The use of Ni-based superalloys in turbine engines has all but been exhausted, with operating temperatures nearing the melting point of these materials. The use of ceramics in turbine engines, particularly ceramic matrix composites such as SiC/C and SiC/SiC, is of interest due to their low density and attractive mechanical properties at elevated temperatures. The same materials are also in consideration for leading edges on hypersonic vehicles. However, SiC-based composites degrade in high temperature environments with low partial pressures of oxygen due to active oxidation, as well as high temperature environments containing water or sand. The need for a protective external coating for SiC-based composites in service is obvious. To date, no coating investigated for SiC/C or SiC/SiC has been proven to be resistant to oxidation and corrosion at intermediate and high temperatures, as well as in environments deficient in oxygen. The Mo-Si-B coating shows great promise in this area, having been proven resistant to attack from oxidation at extreme temperatures, from water vapor and from calcia-magnesia-aluminosilicate (CMAS). The adaptation of the Mo-Si-B coating for ceramic materials is presented in detail here. Evaluation of the coating under a range of oxidation conditions as well as simulated re-entry conditions confirms the efficacy of the Mo-Si-B based coating as protection from catastrophic failure. The key to the oxidation and corrosion resistance is a robust external aluminoborosilica glass layer that forms and flows quickly to cover the substrate, even under the extreme simulated re-entry conditions. Suppression of active oxidation of SiC, which may occur during atmospheric re-entry and hypersonic flight trajectories, has also been examined. In order to adapt the Mo-Si-B based coating to low partial pressures of oxygen and elevated temperatures, controlled amounts of Al were added to the Mo-Si-B based coating. The resulting coating decreased the inward

  4. Transition Metal Coatings for Energy Conversion and Storage; Electrochemical and High Temperature Applications

    Science.gov (United States)

    Falola, Bamidele Daniel

    sequestration easier. One complication of oxyfuel coal combustion is that corrosion problems can be exacerbated due to flue gas recycling, which is employed to dilute the pure O2 feed and reduce the flame temperature. Refractory metal diffusion coatings of Ti and Zr atop P91 steel were created and tested for their ability to prevent corrosion in an oxidizing atmosphere at elevated temperature. Using pack cementation, diffusion coatings of thickness approximately 12 and 20 microm are obtained for Ti and Zr, respectively. The effects of heating to 950°C for 24 hr in 5% O2 in He are studied in situ by thermogravimetric analyses (TGA), and ex situ by SEM analyses and depth profiling by EDX. For Ti-coated, Zr-coated and uncoated P91 samples, extended heating in an oxidizing environment causes relatively thick oxide growth, but extensive oxygen penetration greater than 2.7 mm below the sample surface, and eventual oxide exfoliation, are observed only for the uncoated P91 sample. For the Ti- and Zr-coated samples, oxygen penetrates approximately 16 and 56 microm, respectively, below the surface. in situ TGA verifies that Ti-and Zr-coated P91 samples undergo far smaller mass changes during corrosion than uncoated samples, reaching close to steady state mass after approximately four hours.

  5. Behaviour of HTGR coated fuel particles at high-temperature tests

    International Nuclear Information System (INIS)

    Chernikov, A.S.; Lyutikov, R.A.; Kurbakov, S.D.; Repnikov, V.M.; Khromonozhkin, V.V.; Soloviyov, G.I.

    1990-01-01

    At the temperature range 1200-2600 deg. C prereactor tests of TRISO fuel particles on the base of UO 2 , UC x O y and UO 2 +2Al 2 O 3 . SiO 2 kernels, and also fuel particle models with ZrC kernels were performed. Isothermal annealings carried out at temperatures of 1400-2600 deg. C, thermogradient ones at 1200-2200 deg. C (Δ T = 200-1200 deg. C/cm). It is shown that at heating to 2200 deg. C integrity of fuel particles is limited by different thermal expansion of PyC and SiC coatings, and also by thermal dissociation of SiC. At higher temperatures the failure is caused by development of high pressures within weakened fuel particles. It is found that uranium migration from alloyed fuel (UC x O y , UO 2 +2Al 2 O 3 .SiO 2 ) in the process of annealing is higher than that from UO 2 . (author)

  6. High temperature oxidation behaviour of nanostructured cermet coatings in a mixed CO2 - O2 environment

    Science.gov (United States)

    Farrokhzad, M. A.; Khan, T. I.

    2014-06-01

    Nanostructured ceramic-metallic (cermet) coatings composed of nanosized ceramic particles (α-Al2O3 and TiO2) dispersed in a nickel matrix were co-electrodeposited and then oxidized at 500°C, 600°C and 700°C in a mixed gas using a Thermo-gravimetric Analysis (TGA) apparatus. The mixed gas was composed of 15% CO2, 10% O2 and 75% N2. This research investigates the effects of CO2 and O2 partial pressures on time-depended oxidation rates for coatings and compared them to the results from atmospheric oxidation under similar temperatures. The increase in partial pressure of oxygen due to the presence of CO2 at each tested temperature was calculated and correlated to the oxidation rate of the coatings. The results showed that the presence of CO2 in the system increased the oxidation rate of cermet coatings when compared to atmospheric oxidation at the same temperature. It was also shown that the increase in the oxidation rate is not the result of CO2 acting as the primary oxidant but as a secondary oxidant which results in an increase of the total partial pressure of oxygen and consequently higher oxidation rates. The WDS and XRD analyses results showed that the presence of nanosized TiO2 particles in a nickel matrix can improve oxidation behaviour of the coatings by formation of Ni-Ti compounds on oxidizing surface of the coating which was found beneficiary in reducing the oxidation rates for cermet coatings.

  7. Low Temperature Powder Coating

    Science.gov (United States)

    2011-02-09

    of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) • Legacy primers contain hexavalent chrome • Conventional powder coatings...coatings both in laboratory and field service evaluations • LTCPC allows environmental cost reductions through VOC/HAP elimination and hexavalent ... chrome reduction. • The LTCPC process greatly shortens the coating operation (LTCPC cures much more rapidly then conventional wet coatings) resulting in

  8. High-temperature air oxidation of E110 and Zr-1%Nb alloys claddings with coatings

    International Nuclear Information System (INIS)

    Kuprin, A.S.; Belous, V.A.; Voyevodin, V.N.; Bryk, V.V.; Vasilenko, R.L.; Ovcharenko, V.D.; Tolmachova, G.N.; V'yugov, P.N.

    2014-01-01

    Results of experimental study of the influence of protective vacuum-arc claddings on the base of compounds zirconium-chromium and of its nitrides on air oxidation resistance at temperatures 660, 770, 900, 1020, 1100 deg C during 3600 s. of tubes produced of zirconium alloys E110 and Zr-1%Nb (calcium-thermal alloy of Ukrainian production) are presented. Change of hardness, the width of oxide layer and depth of oxygen penetration into alloys from the side of coating and without coating are investigated by the methods of nanoindentation and by scanning electron microscopy. It is shown that the thickness of oxide layer in zirconium alloys at temperatures 1020 and 1100 deg C from the side of the coating doesn't exceed 5 μm, and from the unprotected side reaches the value of ≥ 120 μm with porous and rough structure. Tubes with coatings save their shape completely independently of the type of alloy; tubes without coatings deform with the production of through cracks

  9. High temperature corrosion in chloridizing atmospheres: development of material quasi-stability diagrams and coatings

    Energy Technology Data Exchange (ETDEWEB)

    Doublet, S.; Schuetze, M. [Karl-Winnacker-Institut der DECHEMA e.V., Theodor-Heuss-Allee 25, D-60486 Frankfurt am Main (Germany)

    2004-07-01

    Chlorine gas is widely encountered in chemical industries, e. g. in waste incinerators and plastic/polymer decomposition mills. The presence of chlorine may significantly reduce the life-time of the components. Although metallic materials have been widely used under such conditions there is still a need for data on the role of the different alloying elements in commercial alloys. The purpose of this work is to produce a clear picture of which alloying elements play a detrimental role and which elements are beneficial. These results can be used as a tool for general assessment of metallic alloys with regard to their performance in chloridizing high temperature environments. A previous study has already been performed in oxidizing-chloridizing atmospheres and led to the elaboration of material quasi-stability diagrams. As a follow-up the present work has been performed in reducing-chloridizing atmospheres in order to validate these diagrams at low partial pressures of oxygen. The behaviour of 9 commercial materials where the content of the major alloying elements was varied in a systematic manner was investigated in reducing-chloridizing atmospheres (in Ar containing up to 2 vol.% Cl{sub 2} and down to 1 ppm O{sub 2}) at 800 deg. C. As the thermodynamical approach to corrosion in such atmospheres could not explain all the phenomena which occur, kinetics calculations i.e. diffusion calculations were carried out. Pack cementation and High Velocity Oxy-Fuel (HVOF) coatings were also developed from the best alloying elements previously found by the calculations and the corrosion experiments. Corrosion tests on the coated materials were then performed in the same conditions as the commercial alloys. (authors)

  10. Development of high-temperature superconducting coated conductor by MOCVD method

    International Nuclear Information System (INIS)

    Kim, Chan Joong; Jun, Byung Hyuk; Jung, Choung Hwan

    2004-07-01

    To fabricate the second generation superconductor wire, coated conductor, we selected MOCVD (Metal organic chemical vapor deposition) method which is commercially available and whose growth rate is very high. The first buffer layer CeO 2 was successfully deposited on the Ni tape. The thick Y-stabilized ZrO 2 layer was thus inserted between two CeO 2 layers by MOCVD method. The c-axis growth of the first CeO 2 , the inserted YSZ and top CeO 2 layer was achieved by optimized the deposition condition for the three buffers. It was found that the YBCO deposition was fairly dependant on the depostion temperature, time, oxygen partial pressure, amount of the source supplied. Especially the thickness of the YBCO films was linearly dedendant on the deposition temperature and time, but current properties was not linearly dependant on the film thickness. The critical current (Ic) of the YBCO film grown on SrTiO 3 and IBAD template were over 100 A/cm-width and 50 A/cm-width at 77 K and 0 field. To establish the MOCVD process, collaboration work with several organizations was made

  11. Shark skin inspired riblet structures as aerodynamically optimized high temperature coatings for blades of aeroengines

    International Nuclear Information System (INIS)

    Büttner, Claudia C; Schulz, Uwe

    2011-01-01

    This paper deals with different structuring methods for high temperature resistant nickel alloys. The ideal structured surface for a possible application on the blades of aeroengines combines high oxidation resistance with low drag in a hot gas flow. The effect of drag reduction due to riblet structured surfaces was originally inspired by shark scales, which have a drag reducing riblet structure. The necessary riblet sizes for effective drag reduction depend on the temperature, pressure and velocity of the flowing medium (gas or liquid). These riblet sizes were calculated for the different sections in an aeroengine. The riblets were successfully produced on a NiCoCrAlY coating by picosecond laser treatment. This method is suitable for larger structures within the range of some tens of micrometers. Furthermore, experiments were performed by depositing different materials through polymer and metal masks via electrodeposition and physical vapor deposition. All fabricated structures were oxidized at 900–1000 °C for up to 100 h to simulate the temperature conditions in an aeroengine. The resulting shape of the riblets was characterized using scanning electron microscopy. The most accurate structures were obtained by using photolithography with a subsequent electrodeposition of nickel. This method is suited for single digit micrometer structures. The reduction of the wall shear stress was measured in an oil channel. The riblet structures prior to oxidation showed a reduction of the wall shear stress of up to 4.9% compared to a normal smooth surface. This proves that the fabricated riblet design can be used as a drag reducing surface

  12. Investigation of Element Effect on High-Temperature Oxidation of HVOF NiCoCrAlX Coatings

    Directory of Open Access Journals (Sweden)

    Pimin Zhang

    2018-04-01

    Full Text Available MCrAlX (M: Ni or Co or both, X: minor elements coatings have been used widely to protect hot components in gas turbines against oxidation and heat corrosion at high temperatures. Understanding the influence of the X-elements on oxidation behavior is important in the design of durable MCrAlX coatings. In this study, NiCoCrAlX coatings doped with Y + Ru and Ce, respectively, were deposited on an Inconel-792 substrate using high velocity oxygen fuel (HVOF. The samples were subjected to isothermal oxidation tests in laboratory air at 900, 1000, and 1100 °C and a cyclic oxidation test between 100 and 1100 °C with a 1-h dwell time at 1100 °C. It was observed that the coating with Ce showed a much higher oxidation rate than the coating with Y + Ru under both isothermal and cyclic oxidation tests. In addition, the Y + Ru-doped coating showed significantly lower β phase depletion due to interdiffusion between the coating and the substrate, resulting from the addition of Ru. Simulation results using a moving phase boundary model and an established oxidation-diffusion model showed that Ru stabilized β grains, which reduced β-depletion of the coating due to substrate interdiffusion. This paper, combining experiment and simulation results, presents a comprehensive study of the influence of Ce and Ru on oxidation behavior, including an investigation of the microstructure evolution in the coating surface and the coating-substrate interface influenced by oxidation time.

  13. The reactive element effect of yttrium and yttrium silicon on high temperature oxidation of NiCrAl coating

    Science.gov (United States)

    Ramandhany, S.; Sugiarti, E.; Desiati, R. D.; Martides, E.; Junianto, E.; Prawara, B.; Sukarto, A.; Tjahjono, A.

    2018-03-01

    The microstructure formed on the bond coat affects the oxidation resistance, particularly the formation of a protective oxide layer. The adhesion of bond coat and TGO increased significantly by addition of reactive element. In the present work, the effect of yttrium and yttrium silicon as reactive element (RE) on NiCrAl coating was investigated. The NiCrAl (without RE) and NiCrAlX (X:Y or YSi) bond coating were deposited on Hastelloy C-276 substrate by High Velocity Oxygen Fuel (HVOF) method. Isothermal oxidation was carried out at 1000 °C for 100 hours. The results showed that the addition of RE could prevent the breakaway oxidation. Therefore, the coating with reactive element were more protective against high temperature oxidation. Furthermore, the oxidation rate of NiCrAlY coating was lower than NiCrAlYSi coating with the total mass change was ±2.394 mg/cm2 after 100 hours of oxidation. The thickness of oxide scale was approximately 1.18 μm consisting of duplex oxide scale of spinel NiCr2O4 in outer scale and protective α-Al2O3 in inner scale.

  14. Oxidation performance of high temperature steels and coatings for future supercritical power plants

    Energy Technology Data Exchange (ETDEWEB)

    Auerkari, Pertti; Salonen, Jorma; Toivonen, Aki; Penttilae, Sami [VTT, Espoo (Finland); Haekkilae, Juha [Foster Wheeler Energia, Varkaus (Finland); Aguero, Alina; Gutierrez, Marcos; Muelas, Raul [INTA, Madrid (Spain); Fry, Tony [NPL (United Kingdom)

    2010-07-01

    The operating efficiency of current and future thermal power plants is largely dependent on the applied temperature and pressure, which are in part limited by the internal oxidation resistance of the structural materials in the steam systems. Alternative and reference materials for such systems have been tested within the COST 536 (ACCEPT) project, including bulk reference materials (ferritic P92 and austenitic 316 LN steels) and several types of coatings under supercritical combined (oxygen) water chemistry (150 ppb DO) at 650 C/300 bar. The testing results from a circulating USC autoclave showed that under such conditions the reference bulk steels performed poorly, with extensive oxidation already after relatively short term exposure to the supercritical medium. Better protection was attained by suitable coatings, although there were clear differences in the protective capabilities between different coating types, and some challenges remain in applying (and repairing) coatings for the internal surfaces of welded structures. The materials performance seems to be worse in supercritical than in subcritical conditions, and this appears not to be only due to the effect of temperature. The implications are considered from the point of view of the operating conditions and materials selection for future power plants. (orig.)

  15. Review of experimental studies of zirconium carbide coated fuel particles for high temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Minato, Kazuo; Ogawa, Toru; Fukuda, Kousaku

    1995-03-01

    Experimental studies of zirconium carbide(ZrC) coated fuel particles were reviewed from the viewpoints of fuel particle designs, fabrication, characterization, fuel performance, and fission product retentiveness. ZrC is known as a refractory and chemically stable compound, so ZrC is a candidate to replace the silicon carbide(SiC) coating layer of the Triso-coated fuel particles. The irradiation experiments, the postirradiation heating tests, and the out-of-reactor experiments showed that the ZrC layer was less susceptible than the SiC layer to chemical attack by fission products and fuel kernels, and that the ZrC-coated fuel particles performed better than the standard Triso-coated fuel particles at high temperatures, especially above 1600degC. The ZrC-coated fuel particles demonstrated better cesium retention than the standard Triso-coated fuel particles though the ZrC layer showed a less effective barrier to ruthenium than the SiC layer. (author) 51 refs

  16. High temperature (salt melt) corrosion tests with ceramic-coated steel

    Energy Technology Data Exchange (ETDEWEB)

    Schütz, Adelheid [University Bayreuth, Metals and Alloys, Ludwig-Thoma-Str. 36b, D-95447 Bayreuth (Germany); Günthner, Martin; Motz, Günter [University Bayreuth, Ceramic Materials Engineering, L.-Thoma-Str. 36b, D-95447 Bayreuth (Germany); Greißl, Oliver [EnBW Kraftwerke AG, Schelmenwasenstraße 13-15, D-70567 Stuttgart (Germany); Glatzel, Uwe, E-mail: uwe.glatzel@uni-bayreuth.de [University Bayreuth, Metals and Alloys, Ludwig-Thoma-Str. 36b, D-95447 Bayreuth (Germany)

    2015-06-01

    Thermal recycling of refuse in waste-to-energy plants reduces the problems connected to waste disposal, and is an alternative source of electric energy. However, the combustion process in waste incinerators results in a fast degradation of the steam-carrying superheater steel tubes by corrosive attack and abrasive wear. Higher firing temperatures are used to increase their efficiency but lead to higher corrosion rates. It is more economical to apply protective coatings on the superheater steel tubes than to replace the base material. In-situ tests were conducted in a waste-to-energy plant first in order to identify and quantify all involved corrosive elements. Laboratory scale experiments with salt melts were developed accordingly. The unprotected low-alloyed steel displayed substantial local corrosion. Corrosion was predominant along the grain boundaries of α-ferrite. The corrosion rate was further increased by FeCl{sub 3} and a mixture of HCL and FeCl{sub 3}. Coatings based on pre-ceramic polymers with specific filler particles were engineered to protect superheater tubes. Tests proved their suitability to protect low-alloYed steel tubes from corrosive attack under conditions typical for superheaterS in waste incinerators, rendering higher firing temperatures in waste-to-energy plants possible. - Highlights: • Corrosion wall thickness losses of 400 μm/2 weeks occurred in a waste incinerator. • Abrasion is a major problem on superheater tubes in waste incinerators. • Laboratory salt melt tests can simulate metal corrosion in waste incinerators. • Corrosion protection coatings for steel (temperature: max. 530 °C) were developed. • Higher steam temperatures are possible in WIs with the developed coatings.

  17. High temperature oxidation interfacial growth kinetics in YSZ thermal barrier coatings with bond coatings of NiCoCrAlY with 0.25% Hf

    Energy Technology Data Exchange (ETDEWEB)

    Soboyejo, W.O. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Mensah, P., E-mail: mensah@engr.subr.edu [Department of Mechanical Engineering, Southern University and A and M College, Baton Rouge, LA 70813 (United States); Diwan, R. [Department of Mechanical Engineering, Southern University and A and M College, Baton Rouge, LA 70813 (United States); Crowe, J. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Akwaboa, S. [Department of Mechanical Engineering, Southern University and A and M College, Baton Rouge, LA 70813 (United States)

    2011-03-15

    Research highlights: {yields} Isothermal oxidation of standard (STD) and vertically cracked (VC) TBCs has been investigated. {yields} The temporal TGO growth kinetics is parabolic in the temperature range between 900 and 1100 deg. C. {yields} Activation energies correspond to growth kinetics controlled by the diffusion of O{sub 2} in Al{sub 2}O{sub 3}. {yields} Variation in oxidation of TBCs is attributed to its microstructure and in-situ oxygen ingression. {yields} Doping TBC bond coat with Hf appears to have potential for enhancing the development of robust TBCs. - Abstract: The results of an experimental study of the high-temperature isothermal oxidation behavior and microstructural evolution in two variations of air plasma sprayed ceramic thermal barrier coatings (TBCs) are discussed in the paper. Two types of TBC specimens were produced for testing. These include a standard and vertically cracked APS. High temperature oxidation was carried out at 900, 1000, 1100 and 1200 deg. C. The experiments were performed in air under isothermal conditions. At each temperature, the specimens were exposed for 25, 50, 75 and 100 h. The corresponding microstructures and microchemistries of the TBC layers were examined using scanning electron microscopy and energy dispersive X-ray spectroscopy. Changes in the dimensions of the thermally grown oxide layer were determined as functions of time and temperature. The evolution of bond coat microstructures/interdiffusion zones and thermally grown oxide layers were compared in the TBC specimens with standard and vertically cracked microstructures.

  18. Properties of arc-sprayed coatings from Fe-based cored wires for high-temperature applications

    Science.gov (United States)

    Korobov, Yu. S.; Nevezhin, S. V.; Filiрpov, M. A.; Makarov, A. V.; Malygina, I. Yu.; Fantozzi, D.; Milanti, A.; Koivuluoto, H.; Vuoristo, P.

    2017-12-01

    Equipment of a thermal power plant is subjected to high temperature oxidation and wear. This raises operating costs through frequent repair of worn parts and high metal consumption. The paper proposes a possible solution to this problem through arc spraying of protective coatings. Cored wires of the Fe-Cr-C basic alloying system are used as a feedstock. Additional alloying by Al, B, Si, Ti and Y allows one to create wear- and heat-resistant coatings, which are an attractive substitute of more expensive Co- and Ni-based materials.

  19. Resistance of various coatings to high temperature corrosion in HCl and SO{sub 2} containing environments

    Energy Technology Data Exchange (ETDEWEB)

    Cizner, Josef; Mlnarik, Jakub; Hruska, Jan [SVUM a.s., Prague (Czech Republic). Lab. of High Temperature Corrosion

    2010-07-01

    For high efficiency of the steam turbines it is necessary to produce steam of temperature at least 400 C, which in conjunction with specific composition of combustion gases causes fireside corrosion problems. The combustion gases contain aggressive compounds ike HCl and SO{sub 2} and some other elements which can form deposits on heat exchanging surfaces e.g. calcium, potassium salts etc. Using of high-alloy steels or nickel-based alloys is very costly and also these materials could have lower thermal conductivity. A cheaper solution is to produce a coating on low (medium)-alloy steel. Common heat-resistant steels show very short lifetime under these conditions. The solution is then to use the appropriate coatings. Some types of coatings can be applied even inside older boilers. In this work we tested many coatings composition (nickel-based, aluminium-based etc. As well as with different processing method - arc sprayed coating, weld deposits, HVOF, etc.) on 16Mo3 steel. In particular their high temperature corrosion behaviour in model atmosphere containing SO{sub 2} and HCl and also under deposit of fly ash was studied. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Rodriguez, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Garcia-Diaz, B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Olson, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fuentes, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Sindelar, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    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

  1. Micro-Structures and High-Temperature Friction-Wear Performances of Laser Cladded Cr–Ni Coatings

    Directory of Open Access Journals (Sweden)

    Li Jiahong

    2018-01-01

    Full Text Available Cr–Ni coatings with the mass ratios of 17% Cr–83% Ni, 20% Cr–80% Ni and 24% Cr–76% Ni were fabricated on H13 hot work mould steel using a laser cladding (LC. The surface–interface morphologies, chemical elements, surface roughness and phase composition of the obtained Cr–Ni coatings were analysed using a scanning electron microscope (SEM, energy disperse spectroscopy (EDS, atomic force microscope (AFM and X–ray diffractometer (XRD, respectively. The friction–wear properties and wear rates of Cr–Ni coatings with the different mass ratios of Cr and Ni at 600 °C were investigated, and the worn morphologies and wear mechanism of Cr–Ni coatings were analysed. The results show that the phases of Cr–Ni coatings with mass ratios of 17% Cr–83% Ni, 20% Cr–80% Ni and 24% Cr–76% Ni are composed of Cr + Ni single-phases and their compounds at the different stoichiometry, the porosities on the Cr–Ni coatings increase with the Cr content increasing. The average coefficient of friction (COF of 17% Cr–83% Ni, 20% Cr–80% Ni and 24% Cr–76% coatings are 1.10, 0.33 and 0.87, respectively, in which the average COF of 20% Cr–80% Ni coating is the lowest, exhibiting the better anti-friction performance. The wear rate of 17% Cr–83% Ni, 20% Cr–80% Ni and 24% Cr–76% Ni coatings is 4.533 × 10−6, 5.433 × 10−6, and 1.761 × 10−6 N−1·s−1, respectively, showing the wear resistance of Cr–Ni coatings at a high temperature increases with the Cr content, in which the wear rate is 24% Cr–76% Ni coating with the better reducing wear. The wear mechanism of 17% Cr–83% Ni and 20% Cr–80% Ni and 24% Cr–76% coatings at 600 °C is primarily adhesive wear, and that of 24% Cr–76% coating is also accompanied by oxidative wear.

  2. High temperature oxidation behavior of hafnium modified NiAl bond coat in EB-PVD thermal barrier coating system

    Energy Technology Data Exchange (ETDEWEB)

    Guo Hongbo; Sun Lidong; Li Hefei [Department of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, No.37 Xueyuan Road, Beijing 100083 (China); Gong Shengkai [Department of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, No.37 Xueyuan Road, Beijing 100083 (China)], E-mail: gongsk@buaa.edu.cn

    2008-06-30

    NiAl coatings doped with 0.5 at.% and 1.5 at.% Hf were produced by co-evaporation of NiAl and Hf ingots by electron beam physical vapor deposition (EB-PVD), respectively. The addition of 0.5 at.% Hf significantly improved the cyclic oxidation resistance of the NiAl coating. The TGO layer in the 1.5 at.% Hf doped NiAl coating is straight; while that in the 0.5 at.% Hf doped coating became undulated after thermal cycling. The doped NiAl thermal barrier coatings (TBCs) revealed improved thermal cycling lifetimes at 1423 K, compared to the undoped TBC. Failure of the 0.5 at.% Hf doped TBC occurred by cracking at the interface between YSZ topcoat and bond coat, while the 1.5 at.% Hf doped TBC cracked at the interface between bond coat and substrate.

  3. High-temperature stable absorber coatings for linear concentrating solar thermal power plants; Hochtemperaturstabile Absorberschichten fuer linear konzentrierende solarthermische Kraftwerke

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrandt, Christina

    2009-03-23

    This work describes the development of new absorber coatings for different applications - para-bolic trough and linear Fresnel collectors - and operating conditions - absorber in vacuum or in air. The demand for higher efficiencies of solar thermal power plants using parabolic trough technology results in higher temperatures in the collectors and on the absorber tubes. As heat losses increase strongly with increasing temperatures, the need for a lower emissivity of the absorber coating at constant absorptivity arises. The linear Fresnel application envisions ab-sorber tubes stable in air at high temperatures of about 450 C, which are to date commercially not available. This work comprises the theoretical background, the modeling and the fabrication of absorber tubes including the technology transfer to a production-size inline sputter coater. In annealing tests and accompanying optical measurements, degradation processes have been observed and specified more precisely by material characterization techniques. The simulations provided the capability of different materials used as potential IR-reflector. The highest selectivity can be achieved by applying silver which consequently has been chosen for the application in absorber coatings of the parabolic trough technology. Thin silver films how-ever need to be stabilized when used at high temperatures. Appropriate barrier layers as well as process and layer parameters were identified. A high selectivity was achieved and stability of the absorber coating for 1200 h at 500 C in vacuum has been demonstrated. For the application in air, silver was also analyzed as a potential IR-reflector. Even though the stability could be increased considerably, it nevertheless proved to be insufficient. The main factors influencing stability in a positive way are the use of higher quality polishing, additional barrier layers and adequate process parameters. This knowledge was applied for developing coatings which are stable in air at

  4. High-temperature deformation and processing maps of Zr-4 metal matrix with dispersed coated surrogate nuclear fuel particles

    Science.gov (United States)

    Chen, Jing; Liu, Huiqun; Zhang, Ruiqian; Li, Gang; Yi, Danqing; Lin, Gaoyong; Guo, Zhen; Liu, Shaoqiang

    2018-06-01

    High-temperature compression deformation of a Zr-4 metal matrix with dispersed coated surrogate nuclear fuel particles was investigated at 750 °C-950 °C with a strain rate of 0.01-1.0 s-1 and height reduction of 20%. Scanning electron microscopy was utilized to investigate the influence of the deformation conditions on the microstructure of the composite and damage to the coated surrogate fuel particles. The results indicated that the flow stress of the composite increased with increasing strain rate and decreasing temperature. The true stress-strain curves showed obvious serrated oscillation characteristics. There were stable deformation ranges at the initial deformation stage with low true strain at strain rate 0.01 s-1 for all measured temperatures. Additionally, the coating on the surface of the surrogate nuclear fuel particles was damaged when the Zr-4 matrix was deformed at conditions of high strain rate and low temperature. The deformation stability was obtained from the processing maps and microstructural characterization. The high-temperature deformation activation energy was 354.22, 407.68, and 433.81 kJ/mol at true strains of 0.02, 0.08, and 0.15, respectively. The optimum deformation parameters for the composite were 900-950 °C and 0.01 s-1. These results are expected to provide guidance for subsequent determination of possible hot working processes for this composite.

  5. Vacuum-arc chromium coatings for Zr-1%Nb alloy protection against high-temperature oxidation in air

    International Nuclear Information System (INIS)

    Kuprin, A.S.; Belous, V.A.; Bryk, V.V.; Vasilenko, R.L.; Voevodin, V.N.; Ovcharenko, V.D.; Tolmacheva, G.N.; Kolodij, I.V.; Lunev, V.M.; Klimenko, I.O.

    2015-01-01

    The effect of vacuum-arc Cr coatings on the alloy E110 resistance to the oxidation in air at temperatures 1020 and 1100 deg C for 3600 s has been investigated. The methods of scanning electron microscope, X-ray analysis and nanoindentation were used to determine the thickness, phase, mechanical properties of coatings and oxide layers. The results show that the chromium coating can effectively protect fuel tubes against high-temperature oxidation in air for one hour. In the coating during oxidation at T = 1100 deg C a Cr 2 O 3 oxide layer of 5 μm thickness is formed preventing further oxygen penetration into the coating, and thus the tube shape is conserved. Under similar test conditions the oxidation of uncoated tubes with formation of a porous monocline oxide of ZrO 2 of a thickness more than ≥ 250 μm is observed, then the deformation and cracking of samples occur and the oxide layer breaks away

  6. Thermal Cycling and High-Temperature Corrosion Tests of Rare Earth Silicate Environmental Barrier Coatings

    Science.gov (United States)

    Darthout, Émilien; Gitzhofer, François

    2017-12-01

    Lutetium and yttrium silicates, enriched with an additional secondary zirconia phase, environmental barrier coatings were synthesized by the solution precursor plasma spraying process on silicon carbide substrates. A custom-made oven was designed for thermal cycling and water vapor corrosion testing. The oven can test four specimens simultaneously and allows to evaluate environmental barrier performances under similar corrosion kinetics compared to turbine engines. Coatings structural evolution has been observed by SEM on the polished cross sections, and phase composition has been analyzed by XRD. All coatings have been thermally cycled between 1300 °C and the ambient temperature, without spallation, due to their porosity and the presence of additional secondary phase which increases the thermal cycling resistance. During water vapor exposure at 1200 °C, rare earth disilicates showed a good stability, which is contradictory with the literature, due to impurities—such as Si- and Al-hydroxides—in the water vapor jets. The presence of vertical cracks allowed the water vapor to reach the substrate and then to corrode it. It has been observed that thin vertical cracks induced some spallation after 24 h of corrosion.

  7. Reconstruction mechanisms of tantalum oxide coatings with low concentrations of silver for high temperature tribological applications

    Energy Technology Data Exchange (ETDEWEB)

    Stone, D. S.; Bischof, M.; Aouadi, S. M., E-mail: samir.aouadi@unt.edu [Department of Material Science and Engineering, University of North Texas, Denton, Texas 76207 (United States); Gao, H.; Martini, A. [School of Engineering, University of California Merced, Merced, California 95343 (United States); Chantharangsi, C.; Paksunchai, C. [Department of Physics, King Mongkut' s University of Technology Thonburi, Bangkok 10140 (Thailand)

    2014-11-10

    Silver tantalate (AgTaO{sub 3}) coatings have been found to exhibit outstanding tribological properties at elevated temperatures. To understand the mechanisms involved in the tribological behavior of the Ag-Ta-O system, tantalum oxide coatings with a small content of silver were produced to investigate the metastable nature of this self-lubricating material. The coatings were produced by unbalanced magnetron sputtering, ball-on-disk wear tested at 750 °C, and subsequently characterized by X-ray diffraction, Scanning Auger Nanoprobe, cross-sectional Scanning Electron Microscopy, and Transmission Electron Microscopy. Complementary molecular dynamic simulations were carried out to investigate changes in the chemical and structural properties at the interface due to sliding for films with varying silver content. Both the experimental characterization and the theoretical modeling showed that silver content affects friction and wear, through the role of silver in film reconstruction during sliding. The results suggest that the relative amount of silver may be used to tune film performance for a given application.

  8. Reconstruction mechanisms of tantalum oxide coatings with low concentrations of silver for high temperature tribological applications

    International Nuclear Information System (INIS)

    Stone, D. S.; Bischof, M.; Aouadi, S. M.; Gao, H.; Martini, A.; Chantharangsi, C.; Paksunchai, C.

    2014-01-01

    Silver tantalate (AgTaO 3 ) coatings have been found to exhibit outstanding tribological properties at elevated temperatures. To understand the mechanisms involved in the tribological behavior of the Ag-Ta-O system, tantalum oxide coatings with a small content of silver were produced to investigate the metastable nature of this self-lubricating material. The coatings were produced by unbalanced magnetron sputtering, ball-on-disk wear tested at 750 °C, and subsequently characterized by X-ray diffraction, Scanning Auger Nanoprobe, cross-sectional Scanning Electron Microscopy, and Transmission Electron Microscopy. Complementary molecular dynamic simulations were carried out to investigate changes in the chemical and structural properties at the interface due to sliding for films with varying silver content. Both the experimental characterization and the theoretical modeling showed that silver content affects friction and wear, through the role of silver in film reconstruction during sliding. The results suggest that the relative amount of silver may be used to tune film performance for a given application

  9. Nuclear reactor pressure vessel with an inner metal coating covered with a high temperature resistant thermal insulator

    International Nuclear Information System (INIS)

    1974-01-01

    The thermal insulator covering the metal coating of a reactor vessel is designed for resisting high temperatures. It comprises one or several porous layers of ceramic fibers or of stacked metal foils, covered with a layer of bricks or ceramic tiles. The latter are fixed in position by fasteners comprising pins fixed to the coating and passing through said porous layers and fasteners (nut or bolts) for individually fixing the bricks to said pins, whereas ceramic plugs mounted on said bricks or tiles provide for the thermal insulation of the pins and of the nuts or bolts; such a thermal insulation can be applied to high-temperature reactors or to fast reactors [fr

  10. Advanced Characterization Techniques for Silicon Carbide and Pyrocarbon Coatings on Fuel Particles for High Temperature Reactors (HTR)

    Energy Technology Data Exchange (ETDEWEB)

    Basini, V.; Charollais, F. [CEA Cadarache, DEN/DEC/SPUA, BP 1, 13108 St Paul Lez Durance (France); Dugne, O. [CEA Marcoule, DEN/DTEC/SCGS BP 17171 30207 Bagnols sur Ceze (France); Garcia, C. [Laboratoire des Composites Thermostructuraux (LCTS), UMR CNRS 5801, 3 allee de La Boetie, 33600 Pessac (France); Perez, M. [CEA Grenoble DRT/DTH/LTH, 17 rue des Martyrs, 38054 Grenoble cedex 9 (France)

    2008-07-01

    Cea and AREVA NP have engaged an extensive research and development program on HTR (high temperature reactor) fuel. The improving of safety of (very) high temperature reactors (V/HTR) is based on the quality of the fuel particles. This requires a good knowledge of the properties of the four-layers TRISO particles designed to retain the uranium and fission products during irradiation or accident conditions. The aim of this work is to characterize exhaustively the structure and the thermomechanical properties of each unirradiated layer (silicon carbide and pyrocarbon coatings) by electron microscopy (SEM, TEM), selected area electronic diffraction (SEAD), thermo reflectance microscopy and nano-indentation. The long term objective of this study is to define pertinent parameters for fuel performance codes used to better understand the thermomechanical behaviour of the coated particles. (authors)

  11. The Interface Structure of High-Temperature Oxidation-Resistant Aluminum-Based Coatings on Titanium Billet Surface

    Science.gov (United States)

    Xu, Zhefeng; Rong, Ju; Yu, Xiaohua; Kun, Meng; Zhan, Zhaolin; Wang, Xiao; Zhang, Yannan

    2017-10-01

    A new type of high-temperature oxidation-resistant aluminum-based coating, on a titanium billet surface, was fabricated by the cold spray method, at a high temperature of 1050°C, for 8 h, under atmospheric pressure. The microstructure of the exposed surface was analyzed via optical microscopy, the microstructure of the coating and elemental diffusion was analyzed via field emission scanning electron microscopy, and the interfacial phases were identified via x-ray diffraction. The Ti-Al binary phase diagram and Gibbs free energy of the stable phase were calculated by Thermo-calc. The results revealed that good oxidation resistant 50-μm-thick coatings were successfully obtained after 8 h at 1050°C. Two layers were obtained after the coating process: an Al2O3 oxidation layer and a TiAl3 transition layer on the Ti-based substrate. The large and brittle Al2O3 grains on the surface, which can be easily spalled off from the surface after thermal processing, protected the substrate against oxidation during processing. In addition, the thermodynamic calculation results were in good agreement with the experimental data.

  12. High DNA stability in white blood cells and buffy coat lysates stored at ambient temperature under anoxic and anhydrous atmosphere.

    Directory of Open Access Journals (Sweden)

    Anne-Lise Fabre

    Full Text Available Conventional storage of blood-derived fractions relies on cold. However, lately, ambient temperature preservation has been evaluated by several independent institutions that see economic and logistic advantages in getting rid of the cold chain. Here we validated a novel procedure for ambient temperature preservation of DNA in white blood cell and buffy coat lysates based on the confinement of the desiccated biospecimens under anoxic and anhydrous atmosphere in original hermetic minicapsules. For this validation we stored encapsulated samples either at ambient temperature or at several elevated temperatures to accelerate aging. We found that DNA extracted from stored samples was of good quality with a yield of extraction as expected. Degradation rates were estimated from the average fragment size of denatured DNA run on agarose gels and from qPCR reactions. At ambient temperature, these rates were too low to be measured but the degradation rate dependence on temperature followed Arrhenius' law, making it possible to extrapolate degradation rates at 25°C. According to these values, the DNA stored in the encapsulated blood products would remain larger than 20 kb after one century at ambient temperature. At last, qPCR experiments demonstrated the compatibility of extracted DNA with routine DNA downstream analyses. Altogether, these results showed that this novel storage method provides an adequate environment for ambient temperature long term storage of high molecular weight DNA in dehydrated lysates of white blood cells and buffy coats.

  13. High DNA stability in white blood cells and buffy coat lysates stored at ambient temperature under anoxic and anhydrous atmosphere

    Science.gov (United States)

    Luis, Aurélie; Colotte, Marthe; Tuffet, Sophie; Bonnet, Jacques

    2017-01-01

    Conventional storage of blood-derived fractions relies on cold. However, lately, ambient temperature preservation has been evaluated by several independent institutions that see economic and logistic advantages in getting rid of the cold chain. Here we validated a novel procedure for ambient temperature preservation of DNA in white blood cell and buffy coat lysates based on the confinement of the desiccated biospecimens under anoxic and anhydrous atmosphere in original hermetic minicapsules. For this validation we stored encapsulated samples either at ambient temperature or at several elevated temperatures to accelerate aging. We found that DNA extracted from stored samples was of good quality with a yield of extraction as expected. Degradation rates were estimated from the average fragment size of denatured DNA run on agarose gels and from qPCR reactions. At ambient temperature, these rates were too low to be measured but the degradation rate dependence on temperature followed Arrhenius’ law, making it possible to extrapolate degradation rates at 25°C. According to these values, the DNA stored in the encapsulated blood products would remain larger than 20 kb after one century at ambient temperature. At last, qPCR experiments demonstrated the compatibility of extracted DNA with routine DNA downstream analyses. Altogether, these results showed that this novel storage method provides an adequate environment for ambient temperature long term storage of high molecular weight DNA in dehydrated lysates of white blood cells and buffy coats. PMID:29190767

  14. Mechanical degradation of coating systems in high-temperature cyclic oxidation

    CSIR Research Space (South Africa)

    Pennefather, RC

    1996-01-01

    Full Text Available Cyclic oxidation tests were performed on a large variety of commercially available overlay coatings. The results confirmed that the composition of the coating as well as the processing method of the coating can affect the life of the system. Coating...

  15. Mechanical degradation of coating systems in high-temperature cyclic oxidation

    CSIR Research Space (South Africa)

    Pennefather, RC

    1995-01-01

    Full Text Available Cyclic oxidation tests were performed on a large variety of commercially available overlay coatings. The results confirmed that the composition of the coating as well as the processing method of the coating can affect the life of the system. Coating...

  16. Automatic X-ray inspection for escaped coated particles in spherical fuel elements of high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Yang, Min; Liu, Qi; Zhao, Hongsheng; Li, Ziqiang; Liu, Bing; Li, Xingdong; Meng, Fanyong

    2014-01-01

    As a core unit of HTGRs (high-temperature gas-cooled reactors), the quality of spherical fuel elements is directly related to the safety and reliability of HTGRs. In line with the design and performance requirements of the spherical fuel elements, no coated fuel particles are permitted to enter the fuel-free zone of a spherical fuel element. For fast and accurate detection of escaped coated fuel particles, X-ray DR (digital radiography) imaging with a step-by-step circular scanning trajectory was adopted for Chinese 10 MW HTGRs. The scanning parameters dominating the volume of the blind zones were optimized to ensure the missing detection of the escaped coated fuel particles is as low as possible. We proposed a dynamic calibration method for tracking the projection of the fuel-free zone accurately, instead of using a fuel-free zone mask of fixed size and position. After the projection data in the fuel-free zone were extracted, image and graphic processing methods were combined for automatic recognition of escaped coated fuel particles, and some practical inspection results were presented. - Highlights: • An X-ray DR imaging system for quality inspection of spherical fuel elements was introduced. • A method for optimizing the blind-zone-related scanning parameter was proposed. • A dynamic calibration method for tracking the fuel-free zone accurately was proposed. • Some inspection results of the disqualified spherical fuel elements with escaped coated fuel particles were presented

  17. Analysis of irradiation-induced stresses in coating layers of coated fuel particles for the High Temperature Engineering Test Reactor (HTTR)

    International Nuclear Information System (INIS)

    Hayashi, Kimio; Kikuchi, Teruo; Fukuda, Kousaku; Sato, Sadao; Toyota, Junji; Shiozawa, Shusaku; Sawa, Kazuhiro; Kashimura, Satoru.

    1991-07-01

    Irradiation-induced stresses in coating layers of coated fuel particles were analyzed by the MICROS-2 code for the fuels of the High Temperature Engineering Test Reactor (HTTR) under its operating conditions. The analyses were made on the standard core fuel (A-type) and the test fuels comprising the advanced SiC-coated particle fuel (B-1 type) and the ZrC-coated particle fuel (B-2 type). For the B-1 type fuel, the stresses were relieved due to the thicker buffer and SiC layers than for the A type fuel. The slightly decreased thickness of the fourth layer for the B-1 type than for the A type fuel had no significant effect on the stresses. As for the B-2 type fuel, almost the same results as for the B-1 type were obtained under an assumption that the ZrC layer as well as the SiC layer undergoes negligible dimension change within the analysis conditions. The obtained results indicated that the B-1 and B-2 type fuels are better than the A type fuel in terms of integrity against the irradiation-induced stresses. Finally, research subjects for development of the analysis code on the fuel behavior are discussed. (author)

  18. Microstructure and High-temperature Wear Behavior of Hot-dipped Aluminized Coating on Different Substrate Materials

    Directory of Open Access Journals (Sweden)

    ZHOU De-qin

    2018-02-01

    Full Text Available The aluminized 45 and H13 steel were prepared via hot-dipped aluminizing and subsequently high-temperature diffusion treatment. The phase, morphology and composition of aluminized coating were characterized by XRD,SEM and EDS methods. Comparative study was performed on unlubricated sliding wear behavior of plating under different substrates on a pin-on-disc wear tester, and the wear mechanism was explored. The results show that the coating is composed of ductile phases FeAl and Fe3Al. Kikendall porosity parallel to the surface exists around the interface of the two phases; because of the carbide particles agglomeration, the bond between the coating and H13 steel is apparently inferior to that in the case of 45 steel; the aluminized 45 steel possesses an excellent wear resistance under 50-200N at 400℃, whereas mild-to-severe wear transition occurs when the temperature increases to 600℃. The wear rate of the aluminized H13 steel reaches the lowest at 400℃, then slightly increases at 600℃. The wear mechanisms of Fe-Al coating are mainly predominated by oxidative mild wear, whereas the extrusion wear prevails in the process for aluminized 45 steel at 600℃.

  19. Role of Oxides and Porosity on High-Temperature Oxidation of Liquid-Fueled HVOF Thermal-Sprayed Ni50Cr Coatings

    Science.gov (United States)

    Song, B.; Bai, M.; Voisey, K. T.; Hussain, T.

    2017-02-01

    High chromium content in Ni50Cr thermally sprayed coatings can generate a dense and protective scale at the surface of coating. Thus, the Ni50Cr coating is widely used in high-temperature oxidation and corrosion applications. A commercially available gas atomized Ni50Cr powder was sprayed onto a power plant steel (ASME P92) using a liquid-fueled high velocity oxy-fuel thermal spray with three processing parameters in this study. Microstructure of as-sprayed coatings was examined using oxygen content analysis, mercury intrusion porosimetry, scanning electron microscope (SEM), energy-dispersive x-ray spectroscopy (EDX) and x-ray diffraction (XRD). Short-term air oxidation tests (4 h) of freestanding coatings (without boiler steel substrate) in a thermogravimetric analyzer at 700 °C were performed to obtain the kinetics of oxidation of the as-sprayed coating. Long-term air oxidation tests (100 h) of the coated substrates were performed at same temperature to obtain the oxidation products for further characterization in detail using SEM/EDX and XRD. In all samples, oxides of various morphologies developed on top of the Ni50Cr coatings. Cr2O3 was the main oxidation product on the surface of all three coatings. The coating with medium porosity and medium oxygen content has the best high-temperature oxidation performance in this study.

  20. Effect of deposition conditions on the properties of pyrolytic silicon carbide coatings for high-temperature gas-cooled reactor fuel particles

    International Nuclear Information System (INIS)

    Stinton, D.P.; Lackey, W.J.

    1977-10-01

    Silicon carbide coatings on HTGR microsphere fuel act as the barrier to contain metallic fission products. Silicon carbide coatings were applied by the decomposition of CH 3 SiCl 3 in a 13-cm-diam (5-in.) fluidized-bed coating furnace. The effects of temperature, CH 3 SiCl 3 supply rate and the H 2 :CH 3 SiCl 3 ratio on coating properties were studied. Deposition temperature was found to control coating density, whole particle crushing strength, coating efficiency, and microstructure. Coating density and microstructure were also partially determined by the H 2 :CH 3 SiCl 3 ratio. From this work, it appears that the rate at which high quality SiC can be deposited can be increased from 0.2 to 0.5 μm/min

  1. Angular dependence of Jc for YBCO coated conductors at low temperature and very high magnetic fields

    International Nuclear Information System (INIS)

    Xu, A; Jaroszynski, J J; Kametani, F; Chen, Z; Larbalestier, D C; Viouchkov, Y L; Chen, Y; Xie, Y; Selvamanickam, V

    2010-01-01

    We present very high field angle dependent critical current density (J c ) data for three recently obtained YBa 2 Cu 3 O 7-x (YBCO) coated conductors used in the construction of high field solenoids. We find that strongly correlated pins, such as BaZrO 3 (BZO) nanorods, while yielding strong c-axis peaks at 77 K, produce almost no measurable contribution at 4 K. Raising the field from c (θ) at low fields to a marked cusp-like behavior at high fields. Transmission electron micrographs show that all samples contain a high density of stacking faults which strengthen the plane correlated pinning parallel to the ab planes produced by the intrinsic ab-plane pinning of the Cu-O charge reservoir layers.

  2. A new high temperature resistant glass–ceramic coating for gas ...

    Indian Academy of Sciences (India)

    Unknown

    resultant coatings showed presence of a number of microcrystalline phases. SEM micrographs ... processing of two novel glass–ceramic coating materials, ... stainless steel tray to yield frit (a friable glassy material). .... Frit (– 20 mesh) powder.

  3. Roll-to-roll coated PBI membranes for high temperature PEM fuel cells

    DEFF Research Database (Denmark)

    Steenberg, Thomas; Hjuler, Hans Aage; Terkelsen, Carina

    2012-01-01

    We employed roll-to-roll coating in the preparation of 40 μm thick poly[2,2′(m-phenylene)-5,5′bibenzimidazole] (PBI) films for fuel cells using both knife-coating (KC) and slot-die (SD) coating. The films were coated directly from a 9% (w/w) solution of PBI in dimethylacetamide onto a sacrificial...

  4. Anti-corrosive Conversion Coating on Aluminium Alloys Using High Temperature Steam

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    or convert to a functional conversion coating. In the last several decades chromate conversion coating (CrCCs) have been the most common conversion coatings used for aluminium alloys. Due to the toxicity of the hexavalent chrome, however, environmental friendly alternatives to CrCCs have been investigated...

  5. Novel, Functionally Graded Coating System for Reusable, Very High Temperature Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal addresses some of the most challenging materials issues with respect to multi-mission, very high temperature, up to 4000°F, applications. The very...

  6. Study of the corrosion of metallic coatings and alloys containing aluminum in a mixed atmosphere - sulphur, oxygen - at high temperatures

    International Nuclear Information System (INIS)

    Fellmann, Daniel

    1982-01-01

    The objective of this research thesis is the development of materials for a sulphur experimental loop allowing the thermodynamic properties of such an energy cycle to be checked. As solutions must comply with industrial methods, rare materials are excluded as they are too expensive or difficult to implement. Iron-based materials have been tested but could not have at the same time a good corrosion resistance and high temperature forming and mechanical toughness properties. Therefore, metallic coatings have been chosen, specifically alumina. After having reported a bibliographical study on corrosion by sulphur vapour and by oxygen and by sulphur-oxygen, the author presents the experimental materials and methods. Then, the author reports the study of mixed corrosion (by sulphur and oxygen together) of metallic alloys (ferritic and austeno-ferritic alloys, aluminium and titanium alloys), and of the corrosion of FeAlx coatings, of AlTix alloys [fr

  7. Tribological behaviour at high temperature of hard CrAlN coatings doped with Y or Zr

    International Nuclear Information System (INIS)

    Sánchez-López, J.C.; Contreras, A.; Domínguez-Meister, S.; García-Luis, A.; Brizuela, M.

    2014-01-01

    The tribological properties of CrAlN, CrAlYN and CrAlZrN coatings deposited by direct current reactive magnetron sputtering are studied by means of pin-on-disc experiments at room temperature, 300, 500 and 650 °C using alumina balls as counterparts. The influence of the metallic composition (Al, Y and Zr) on the friction, wear properties and oxidation resistance is studied by means of scanning electron microscopy, energy dispersive X-ray analysis and Raman analysis of the contact region after the friction tests. The results obtained allow us to classify the tribological behaviour of the CrAl(Y,Zr)N coatings into three groups according to the nature of the dopant and aluminium content. The sliding wear mechanism is characterized by the formation of an overcoat rich in chromium and aluminium oxides whose particular composition is determined by the initial chemical characteristics of the coating and the testing temperature. The fraction of Cr 2 O 3 becomes more significant as the Al content decreases and the temperature increases. The addition of Y, and particularly Zr, favours the preferential formation of Cr 2 O 3 versus CrO 2 leading to a reduction of friction and wear of the counterpart. Conversely, the tribological behaviour of pure CrAlN coatings is characterized by higher friction but lower film wear rates as a result of higher hardness and major presence of aluminium oxides on the coating surface. - Highlights: • Comparative tribological study at high temperature of CrAlN, CrAlYN and CrAlZrN films • Fraction of Cr 2 O 3 raises as the Al content decreases and the temperature increases. • Zr doping favours lower and steady friction coefficient due to higher Cr 2 O 3 formation. • Sliding wear mechanism becomes predominantly abrasive as the Al content increases. • Excellent tribological performance of CrAlN doped with low Y contents (≈ 2 at.%)

  8. Investigation of the influence on residual stresses of porosity in high temperature ZrO2 coatings on Ag tape for magnet technologies

    International Nuclear Information System (INIS)

    Arman, Yusuf; Aktas, Mehmet; Celik, Erdal; Mutlu, Ibrahim H.; Sayman, Onur

    2007-01-01

    The present paper reports on the effect on residual stresses of porosity in high temperature ZrO 2 coatings on Ag tape for magnet technologies. ZrO 2 coatings were fabricated on Ag tape substrate using a reel-to-reel sol-gel system. The microstructural evolution of high temperature ZrO 2 coatings was investigated by a scanning electron microscope (SEM). SEM observations revealed that ZrO 2 coatings with crack had some porosity and mosaic structure. Stress analysis was carried out on ZrO 2 coatings with porosity on Ag tape substrates under cryogenic conditions by using classical lamination theory (CLT) for elastic solution and finite element method (FEM) for elasto-plastic solution in the temperature range of 0 o C to -223 o C in liquid helium media. Because of the static equilibrium, tensile force is applied to the Ag substrate, by ZrO 2 coating. The stress component (σ x ) values change rapidly at coating-substrate interface owing to the different moduli of elasticity and thermal expansion coefficient. In spite of the thickness of Ag substrate, the stress components vary from tensile to compressive. In addition, along the thickness of ZrO 2 coating and Ag substrate system, the stress distribution changes linearly. FEM results demonstrate that the failure does not occur in ZrO 2 coating for all porosities due to its high yield strength

  9. Fluoride-Salt-Cooled High-Temperature Reactor (FHR) with Silicon-Carbide-Matrix Coated-Particle Fuel

    International Nuclear Information System (INIS)

    Forsberg, C. W.; Snead, Lance Lewis; Katoh, Yutai

    2012-01-01

    The FHR is a new reactor concept that uses coated-particle fuel and a low-pressure liquid-salt coolant. Its neutronics are similar to a high-temperature gas-cooled reactor (HTGR). The power density is 5 to 10 times higher because of the superior cooling properties of liquids versus gases. The leading candidate coolant salt is a mixture of 7 LiF and BeF 2 (FLiBe) possessing a boiling point above 1300 C and the figure of merit ρC p (volumetric heat capacity) for the salt slightly superior to water. Studies are underway to define a near-term base-line concept while understanding longer-term options. Near-term options use graphite-matrix coated-particle fuel where the graphite is both a structural component and the primary neutron moderator. It is the same basic fuel used in HTGRs. The fuel can take several geometric forms with a pebble bed being the leading contender. Recent work on silicon-carbide-matrix (SiCm) coated-particle fuel may create a second longer-term fuel option. SiCm coated-particle fuels are currently being investigated for use in light-water reactors. The replacement of the graphite matrix with a SiCm creates a new family of fuels. The first motivation behind the effort is to take advantage of the superior radiation resistance of SiC compared to graphite in order to provide a stable matrix for hosting coated fuel particles. The second motivation is a much more rugged fuel under accident, repository, and other conditions.

  10. High temperature oxidation behavior of gamma-nickel+gamma'-nickel aluminum alloys and coatings modified with platinum and reactive elements

    Science.gov (United States)

    Mu, Nan

    Materials for high-pressure turbine blades must be able to operate in the high-temperature gases (above 1000°C) emerging from the combustion chamber. Accordingly, the development of nickel-based superalloys has been constantly motivated by the need to have improved engine efficiency, reliability and service lifetime under the harsh conditions imposed by the turbine environment. However, the melting point of nickel (1455°C) provides a natural ceiling for the temperature capability of nickel-based superalloys. Thus, surface-engineered turbine components with modified diffusion coatings and overlay coatings are used. Theses coatings are capable of forming a compact and adherent oxide scale, which greatly impedes the further transport of reactants between the high-temperature gases and the underlying metal and thus reducing attack by the atmosphere. Typically, these coatings contain beta-NiAl as a principal constituent phase in order to have sufficient aluminum content to form an Al2O3 scale at elevated temperatures. The drawbacks to the currently-used beta-based coatings, such as phase instabilities, associated stresses induced by such phase instabilities, and extensive coating/substrate interdiffusion, are major motivations in this study to seek next-generation coatings. The high-temperature oxidation resistance of novel Pt+Hf-modified gamma-Ni+gamma'-Ni 3Al-based alloys and coatings were investigated in this study. Both early-stage and 4-days isothermal oxidation behavior of single-phase gamma-Ni and gamma'-Ni3Al alloys were assessed by examining the weight changes, oxide-scale structures, and elemental concentration profiles through the scales and subsurface alloy regions. It was found that Pt promotes Al 2O3 formation by suppressing the NiO growth on both gamma-Ni and gamma'-Ni3Al single-phase alloys. This effect increases with increasing Pt content. Moreover, Pt exhibits this effect even at lower temperatures (˜970°C) in the very early stage of oxidation. It

  11. Recovery and recycling of uranium from rejected coated particles for compact high temperature reactors

    Energy Technology Data Exchange (ETDEWEB)

    Pai, Rajesh V., E-mail: pairajesh007@gmail.com [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai (India); Mollick, P.K. [Powder Metallurgy Division, Bhabha Atomic Research Centre, Mumbai (India); Kumar, Ashok [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai (India); Banerjee, J. [Radiometullurgy Division, Bhabha Atomic Research Centre, Mumbai (India); Radhakrishna, J. [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai (India); Chakravartty, J.K. [Powder Metallurgy Division, Bhabha Atomic Research Centre, Mumbai (India)

    2016-05-15

    UO{sub 2} microspheres prepared by internal gelation technique were coated with pyrolytic carbon and silicon carbide using CVD technique. The particles which were not meeting the specifications were rejected. The rejected/failed UO{sub 2} based coated particles prepared by CVD technique was used for oxidation and recovery and recycling. The oxidation behaviour of sintered UO{sub 2} microspheres coated with different layers of carbon and SiC was studied by thermal techniques to develop a method for recycling and recovery of uranium from the failed/rejected coated particles. It was observed that the complete removal of outer carbon from the spheres is difficult. The crushing of microspheres enabled easier accessibility of oxygen and oxidation of carbon and uranium at 800–1000 °C. With the optimized process of multiple crushing using die & plunger and sieving the broken coated layers, we could recycle around fifty percent of the UO{sub 2} microspheres which could be directly recoated. The rest of the particles were recycled using a wet recycling method. - Highlights: • The oxidation behaviour of coated particles was studied in air, O{sub 2} and moist O{sub 2}. • It was observed that coated layers cannot be completely removed by mere oxidation. • Complete recovery of uranium from the rejected coated particles has been carried out using a combination of dry and wet recovery scheme. • A crushing step prior to oxidation is needed for full recovery of uranium from the coated particles.

  12. High temperature properties of the Cr-Nb-Al-N coatings with increasing Al contents

    OpenAIRE

    Li, W. Z.; Polcar, T.; Evaristo, M.; Cavaleiro, A.

    2013-01-01

    Cr-Nb-Al-N coatings with Al content from 0 to 12 at.% were deposited by d.c. reactive magnetron sputtering. The coatings were annealed in protective atmosphere at 800 and 900 °C for 1 h and exposed to air at 800, 900 and 1200 °C for different times. The chemical composition, structure, microstructure, hardness and adhesive/cohesive strength of the coatings, in as-deposited and annealed conditions, were investigated and the oxidation resistance was evaluated. As expected, the Al content increa...

  13. Status and prospects on development of yttrium-based high-temperature superconducting coated conductor

    International Nuclear Information System (INIS)

    Izumi, Teruo; Yanagi, Nagato

    2017-01-01

    Development of a large-sized large-current conductor using a high-temperature superconducting wire rod based on copper oxide has been started worldwide for the purpose of applying it as an option of a magnet for a nuclear fusion prototype reactor. There is yttrium-based thin film wire rod as a promising candidate. Japan is leading the development of this wire rod for many years, aiming to apply it to power equipment and the like. This paper explained the history of wire rod development, basic superconducting properties and manufacturing method, and latest achievements, and overviewed the feasibility of application to nuclear fusion reactor magnets. At present, the use of niobium-based low-temperature superconducting wire rod that is used in ITER is the basic idea. On the other hand, the development of wire rod using a copper oxide type high-temperature superconductor (HTS) has also been started. HTS wire rod is evaluated as suitable for application to nuclear fusion magnets due to its superior critical current characteristics and high mechanical rigidity up to high magnetic fields at high temperatures of yttrium. As current development progress, there are development of high-quality wire rod in the magnetic field and development of low AC loss wire rod. As future prospects, cost reduction due to mass production and improvement of yield, and investigation of low-resistance connection technology are being studied. The remaining future challenges of yttrium-based HTS are improvement of the anisotropy, influence on neutron irradiation, and problem of activation. (A.O.)

  14. Neutron irradiation and high temperature effects on amorphous Fe-based nano-coatings on steel - A macroscopic assessment

    Science.gov (United States)

    Simos, N.; Zhong, Z.; Dooryhee, E.; Ghose, S.; Gill, S.; Camino, F.; Şavklıyıldız, İ.; Akdoğan, E. K.

    2017-06-01

    The study revealed that loss of ductility in an amorphous Fe-alloy coating on a steel substrate composite structure was essentially prevented from occurring, following radiation with modest neutron doses of ∼2 × 1018 n/cm2. At the higher neutron dose of ∼2 × 1019, macroscopic stress-strain analysis showed that the amorphous Fe-alloy nanostructured coating, while still amorphous, experienced radiation-induced embrittlement, no longer offering protection against ductility loss in the coating-substrate composite structure. Neutron irradiation in a corrosive environment revealed exemplary oxidation/corrosion resistance of the amorphous Fe-alloy coating, which is attributed to the formation of the Fe2B phase in the coating. To establish the impact of elevated temperatures on the amorphous-to-crystalline transition in the amorphous Fe-alloy, electron microscopy was carried out which confirmed the radiation-induced suppression of crystallization in the amorphous Fe-alloy nanostructured coating.

  15. Neutron irradiation and high temperature effects on amorphous Fe-based nano-coatings on steel – A macroscopic assessment

    International Nuclear Information System (INIS)

    Simos, N.; Zhong, Z.; Dooryhee, E.; Ghose, S.; Gill, S.

    2017-01-01

    Here, this study revealed that loss of ductility in an amorphous Fe-alloy coating on a steel substrate composite structure was essentially prevented from occurring, following radiation with modest neutron doses of ~2 x 10 18 n/cm 2 . At the higher neutron dose of ~2 x 10 19 , macroscopic stress-strain analysis showed that the amorphous Fe-alloy nanostructured coating, while still amorphous, experienced radiation-induced embrittlement, no longer offering protection against ductility loss in the coating-substrate composite structure. Neutron irradiation in a corrosive environment revealed exemplary oxidation/corrosion resistance of the amorphous Fe-alloy coating, which is attributed to the formation of the Fe 2 B phase in the coating. To establish the impact of elevated temperatures on the amorphous-to-crystalline transition in the amorphous Fe-alloy, electron microscopy was carried out which confirmed the radiation-induced suppression of crystallization in the amorphous Fe-alloy nanostructured coating.

  16. Advanced High-Temperature Reactor for Production of Electricity and Hydrogen: Molten-Salt-Coolant, Graphite-Coated-Particle-Fuel

    International Nuclear Information System (INIS)

    Forsberg, C.W.

    2002-01-01

    The objective of the Advanced High-Temperature Reactor (AHTR) is to provide the very high temperatures necessary to enable low-cost (1) efficient thermochemical production of hydrogen and (2) efficient production of electricity. The proposed AHTR uses coated-particle graphite fuel similar to the fuel used in modular high-temperature gas-cooled reactors (MHTGRs), such as the General Atomics gas turbine-modular helium reactor (GT-MHR). However, unlike the MHTGRs, the AHTR uses a molten salt coolant with a pool configuration, similar to that of the PRISM liquid metal reactor. A multi-reheat helium Brayton (gas-turbine) cycle, with efficiencies >50%, is used to produce electricity. This approach (1) minimizes requirements for new technology development and (2) results in an advanced reactor concept that operates at essentially ambient pressures and at very high temperatures. The low-pressure molten-salt coolant, with its high heat capacity and natural circulation heat transfer capability, creates the potential for (1) exceptionally robust safety (including passive decay-heat removal) and (2) allows scaling to large reactor sizes [∼1000 Mw(e)] with passive safety systems to provide the potential for improved economics

  17. High-temperature oxidation of CrN/AlN multilayer coatings

    International Nuclear Information System (INIS)

    Bardi, U.; Chenakin, S.P.; Ghezzi, F.; Giolli, C.; Goruppa, A.; Lavacchi, A.; Miorin, E.; Pagura, C.; Tolstogouzov, A.

    2005-01-01

    Experiments are reported on sputter depth profiling of CrN/AlN multilayer abrasive coatings by secondary ion mass spectrometry (SIMS) coupled with sample current measurements (SCM). The coatings were deposited by a closed-field unbalanced magnetron sputtering. It is shown that after oxidation tests, performed in air at 900 deg. C for 2 h and at 1100 deg. C for 4 h, the layered structure begins to degrade but is not destroyed completely. Oxidation at 1100 deg. C for 20 h causes total destruction of the coatings that can be attributed to a fast diffusion of oxygen, nickel, manganese and other elements along defect paths (grain boundaries, dislocations, etc.) in the coating. There are practically no nitrides in the near-surface layer after such a treatment and all the metallic components are in the oxidized form as follows from the data obtained by X-ray photoelectron spectroscopy (XPS). According to XPS and mass-resolved ion scattering spectrometry (MARISS), the surface content of Al in the heat-treated coatings has decreased in comparison with the as-received sample and that of Cr increased. Both XPS and MARISS data exhibit real increase in superficial concentration of the substrate materials (Mn and Ni) that is controversial if using SIMS alone. SCM turned out to be an informative depth profiling method complementary to more expensive and complicated SIMS, being particularly useful for structures with different secondary electron emission properties of the layers. SCM with predetermined SIMS calibration allows a routine characterization of coatings and other multilayer structures, particularly, in situations where the expenses of analysis can be justified

  18. The behavior of ZrO_2/20%Y_2O_3 and Al_2O_3 coatings deposited on aluminum alloys at high temperature regime

    International Nuclear Information System (INIS)

    Pintilei, G.L.; Crismaru, V.I.; Abrudeanu, M.; Munteanu, C.; Baciu, E.R.; Istrate, B.; Basescu, N.

    2015-01-01

    Highlights: • In both the ZrO_2/20%Y_2O_3 and Al_2O_3 coatings the high temperature caused a decrease of pores volume and a lower thickness of the interface between successive splats. • The NiCr bond layer in the sample with a ZrO_2/20%Y_2O_3 suffered a fragmentation due to high temperature exposure and thermal expansion which can lead to coating exfoliation. • The NiCr bond layer in the sample with an Al_2O_3 coating showed an increase of pore volume due to high temperature. - Abstract: Aluminum alloy present numerous advantages like lightness, high specific strength and diversity which recommend them to a high number of applications from different fields. In extreme environments the protection of aluminum alloys is difficult and requires a high number of requirements like high temperature resistance, thermal fatigue resistance, corrosion fatigue resistance and galvanic corrosion resistance. To obtain these characteristics coatings can be applied to the surfaces so they can enhance the mechanical and chemical properties of the parts. In this paper two coatings were considered for deposition on an AA2024 aluminum alloy, ZrO_2/20%Y_2O_3 and Al_2O_3. To obtain a better adherence of the coating to the base material an additional bond layer of NiCr is used. Both the coatings and bond layer were deposited by atmospheric plasma spraying on the samples. The samples were subjected to a temperature of 500 °C and after that slowly cooled to room temperature. The samples were analyzed by electron microscopy and X-ray diffraction to determine the morphological and phase changes that occurred during the temperature exposure. To determine the stress level in the parts due to thermal expansion a finite element analysis was performed in the same conditions as the tests.

  19. Numerical simulation of flow boiling for organic fluid with high saturation temperature in vertical porous coated tube

    Energy Technology Data Exchange (ETDEWEB)

    Yang Dong, E-mail: dyang@mail.xjtu.edu.cn [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an, Shaanxi Province 710049 (China); Pan Jie; Wu Yanhua; Chen Tingkuan [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an, Shaanxi Province 710049 (China); Zhou, Chenn Q. [Department of Mechanical Engineering, Purdue University Calumet, Hammond, IN 46323 (United States)

    2011-08-15

    Highlights: > A model is developed for the prediction of flow boiling in vertical porous tubes. > The model assumes that the nucleate boiling plays an important role. > The present model can predict most of the experimental values within {+-}20%. > The results indicate the nucleate boiling contribution decreases from 50% to 15%. - Abstract: A semi-analytical model is developed for the prediction of flow boiling heat transfer inside vertical porous coated tubes. The model assumes that the forced convection and nucleate boiling coexist together in the annular flow regime. Conservations of mass, momentum, and energy are used to solve for the liquid film thickness and temperature. The heat flux due to nucleate boiling consists of those inside and outside micro-tunnels. To close the equations, a detailed analysis of various forces acting on the bubble is presented to predict its mean departure diameter. The active nucleation site density of porous layer is determined from the pool boiling correlation by introducing suppression factor. The flow boiling heat transfer coefficients of organic fluid (cumene) with high saturation temperature in a vertical flame-spraying porous coated tube are studied numerically. It is shown that the present model can predict most of the experimental values within {+-}20%. The numerical results also indicate that the nucleate boiling contribution to the overall heat transfer coefficient decreases from 50% to 15% with vapor quality increasing from 0.1 to 0.5.

  20. Characterization of Modified Tapioca Starch Solutions and Their Sprays for High Temperature Coating Applications

    Science.gov (United States)

    Naz, M. Y.; Sulaiman, S. A.; Ariwahjoedi, B.; Shaari, Ku Zilati Ku

    2014-01-01

    The objective of the research was to understand and improve the unusual physical and atomization properties of the complexes/adhesives derived from the tapioca starch by addition of borate and urea. The characterization of physical properties of the synthesized adhesives was carried out by determining the effect of temperature, shear rate, and mass concentration of thickener/stabilizer on the complex viscosity, density, and surface tension. In later stage, phenomenological analyses of spray jet breakup of heated complexes were performed in still air. Using a high speed digital camera, the jet breakup dynamics were visualized as a function of the system input parameters. The further analysis of the grabbed images confirmed the strong influence of the input processing parameters on full cone spray patternation. It was also predicted that the heated starch adhesive solutions generate a dispersed spray pattern by utilizing the partial evaporation of the spraying medium. Below 40°C of heating temperature, the radial spray cone width and angle did not vary significantly with increasing Reynolds and Weber numbers at early injection phases leading to increased macroscopic spray propagation. The discharge coefficient, mean flow rate, and mean flow velocity were significantly influenced by the load pressure but less affected by the temperature. PMID:24592165

  1. Corrosion behavior of Al-Fe-sputtering-coated steel, high chromium steels, refractory metals and ceramics in high temperature Pb-Bi

    International Nuclear Information System (INIS)

    Abu Khalid, Rivai; Minoru, Takahashi

    2007-01-01

    Corrosion tests of Al-Fe-coated steel, high chromium steels, refractory metals and ceramics were carried out in high temperature Pb-Bi at 700 C degrees. Oxygen concentrations in this experiment were 6.8*10 -7 wt.% for Al-Fe-coated steels and 5*10 -6 wt.% for high chromium steels, refractory metals and ceramics. All specimens were immersed in molten Pb-Bi in a corrosion test pot for 1.000 hours. Coating was done with using the unbalanced magnetron sputtering (UBMS) technique to protect the steel from corrosion. Sputtering targets were Al and SUS-304. Al-Fe alloy was coated on STBA26 samples. The Al-Fe alloy-coated layer could be a good protection layer on the surface of steel. The whole of the Al-Fe-coated layer still remained on the base surface of specimen. No penetration of Pb-Bi into this layer and the matrix of the specimen. For high chromium steels i.e. SUS430 and Recloy10, the oxide layer formed in the early time could not prevent the penetration of Pb-Bi into the base of the steels. Refractory metals of tungsten (W) and molybdenum (Mo) had high corrosion resistance with no penetration of Pb-Bi into their matrix. Penetration of Pb-Bi into the matrix of niobium (Nb) was observed. Ceramic materials were SiC and Ti 3 SiC 2 . The ceramic materials of SiC and Ti 3 SiC 2 had high corrosion resistance with no penetration of Pb-Bi into their matrix. (authors)

  2. High temperature growth kinetics and texture of surface-oxidised NiO for coated superconductor applications

    Energy Technology Data Exchange (ETDEWEB)

    Kursumovic, A; Tomov, R; Huehne, R; Glowacki, B A; Everts, J E; Tuissi, A; Villa, E; Holzapfel, B

    2003-03-15

    Thick NiO films were grown in air, on biaxially textured (0 0 1) Ni and as-rolled Ni tapes, at temperatures from 1050 to 1350 deg. C. Ni diffusion through the NiO film mainly contributes to the growth since is much faster than oxygen diffusion and occurs by a vacancy diffusion mechanism in the lattice at high temperatures. Parabolic growth kinetics were found for both NiO film thickness and grain growth, and compared with the literature data. Competitive growth of (1 1 1) and (0 0 1) oriented grains establishes the final NiO orientation at temperatures below 1250 deg. C, while at higher temperatures leakage diffusion at/towards grain boundaries, grain coarsening and (1 1 0) oriented grains disrupt the (1 0 0) texture. Hence, development of epitaxy of NiO on textured Ni tapes was found to be largely due to growth kinetics depending on both, time and temperature. We report here a systematic study of the microstructure and kinetics of formation of textured NiO substrate for application as a buffer layer in coated conductor technology.

  3. Comparison of high temperature wear behaviour of plasma sprayed WC–Co coated and hard chromium plated AISI 304 austenitic stainless steel

    International Nuclear Information System (INIS)

    Balamurugan, G.M.; Duraiselvam, Muthukannan; Anandakrishnan, V.

    2012-01-01

    Highlights: ► WC–12wt.%Co powders were deposited to a thickness of 300 μm on to steel substrates. ► The micro hardness of the above coatings was lower than that of chromium plating. ► Wear resistance of chromium coating was increased up to five times of AISI 304 austenitic stainless steel. ► Wear resistance of chromium coat higher than plasma coat at different temperatures. -- Abstract: The wear behaviour of plasma sprayed coating and hard chrome plating on AISI 304 austenitic stainless steel substrate is experimentally investigated in unlubricated conditions. Experiments were conducted at different temperatures (room temp, 100 °C, 200 °C and 300 °C) with 50 N load and 1 m/s sliding velocity. Wear tests were carried out by dry sliding contact of EN-24 medium carbon steel pin as counterpart on a pin-on-disc wear testing machine. In both coatings, specimens were characterised by hardness, microstructure, coating density and sliding wear resistance. Wear studies showed that the hard chromium coating exhibited improved tribological performance than that of the plasma sprayed WC–Co coating. X-ray diffraction analysis (XRD) of the coatings showed that the better wear resistance at high temperature has been attributed to the formation of a protective oxide layer at the surface during sliding. The wear mechanisms were investigated through scanning electron microscopy (SEM) and XRD. It was observed that the chromium coating provided higher hardness, good adhesion with the substrate and nearly five times the wear resistance than that obtained by uncoated AISI 304 austenitic stainless steel.

  4. Effect of Carbide Dissolution on Chlorine Induced High Temperature Corrosion of HVOF and HVAF Sprayed Cr3C2-NiCrMoNb Coatings

    Science.gov (United States)

    Fantozzi, D.; Matikainen, V.; Uusitalo, M.; Koivuluoto, H.; Vuoristo, P.

    2018-01-01

    Highly corrosion- and wear-resistant thermally sprayed chromium carbide (Cr3C2)-based cermet coatings are nowadays a potential highly durable solution to allow traditional fluidized bed combustors (FBC) to be operated with ecological waste and biomass fuels. However, the heat input of thermal spray causes carbide dissolution in the metal binder. This results in the formation of carbon saturated metastable phases, which can affect the behavior of the materials during exposure. This study analyses the effect of carbide dissolution in the metal matrix of Cr3C2-50NiCrMoNb coatings and its effect on chlorine-induced high-temperature corrosion. Four coatings were thermally sprayed with HVAF and HVOF techniques in order to obtain microstructures with increasing amount of carbide dissolution in the metal matrix. The coatings were heat-treated in an inert argon atmosphere to induce secondary carbide precipitation. As-sprayed and heat-treated self-standing coatings were covered with KCl, and their corrosion resistance was investigated with thermogravimetric analysis (TGA) and ordinary high-temperature corrosion test at 550 °C for 4 and 72 h, respectively. High carbon dissolution in the metal matrix appeared to be detrimental against chlorine-induced high-temperature corrosion. The microstructural changes induced by the heat treatment hindered the corrosion onset in the coatings.

  5. Calculating transport AC losses in stacks of high temperature superconductor coated conductors with magnetic substrates using FEM

    International Nuclear Information System (INIS)

    Ainslie, Mark D.; Flack, Tim J.; Campbell, Archie M.

    2012-01-01

    Properties of stacks of HTS coated conductors with and without a magnetic substrate. Non-magnetic substrate model is consistent with existing methods. Presence of a magnetic substrate increases the total AC loss of the stack. Differences and similarities between certain tapes within stacks are explained. Ferromagnetic loss of substrate negligible in most cases except small currents/fields. In this paper, the authors investigate the electromagnetic properties of stacks of high temperature superconductor (HTS) coated conductors with a particular focus on calculating the total transport AC loss. The cross-section of superconducting cables and coils is often modeled as a two-dimensional stack of coated conductors, and these stacks can be used to estimate the AC loss of a practical device. This paper uses a symmetric two dimensional (2D) finite element model based on the H formulation, and a detailed investigation into the effects of a magnetic substrate on the transport AC loss of a stack is presented. The number of coated conductors in each stack is varied from 1 to 150, and three types of substrate are compared: non-magnetic weakly magnetic and strongly magnetic. The non-magnetic substrate model is comparable with results from existing models for the limiting cases of a single tape (Norris) and an infinite stack (Clem). The presence of a magnetic substrate increases the total AC loss of the stack, due to an increased localized magnetic flux density, and the stronger the magnetic material, the further the flux penetrates into the stack overall. The AC loss is calculated for certain tapes within the stack, and the differences and similarities between the losses throughout the stack are explained using the magnetic flux penetration and current density distributions in those tapes. The ferromagnetic loss of the substrate itself is found to be negligible in most cases, except for small magnitudes of current. Applying these findings to practical applications, where AC

  6. Detailed Reaction Kinetics for CFD Modeling of Nuclear Fuel Pellet Coating for High Temperature Gas-Cooled Reactors

    International Nuclear Information System (INIS)

    Battaglia, Francine

    2008-01-01

    The research project was related to the Advanced Fuel Cycle Initiative and was in direct alignment with advancing knowledge in the area of Nuclear Fuel Development related to the use of TRISO fuels for high-temperature reactors. The importance of properly coating nuclear fuel pellets received a renewed interest for the safe production of nuclear power to help meet the energy requirements of the United States. High-temperature gas-cooled nuclear reactors use fuel in the form of coated uranium particles, and it is the coating process that was of importance to this project. The coating process requires four coating layers to retain radioactive fission products from escaping into the environment. The first layer consists of porous carbon and serves as a buffer layer to attenuate the fission and accommodate the fuel kernel swelling. The second (inner) layer is of pyrocarbon and provides protection from fission products and supports the third layer, which is silicon carbide. The final (outer) layer is also pyrocarbon and provides a bonding surface and protective barrier for the entire pellet. The coating procedures for the silicon carbide and the outer pyrocarbon layers require knowledge of the detailed kinetics of the reaction processes in the gas phase and at the surfaces where the particles interact with the reactor walls. The intent of this project was to acquire detailed information on the reaction kinetics for the chemical vapor deposition (CVD) of carbon and silicon carbine on uranium fuel pellets, including the location of transition state structures, evaluation of the associated activation energies, and the use of these activation energies in the prediction of reaction rate constants. After the detailed reaction kinetics were determined, the reactions were implemented and tested in a computational fluid dynamics model, MFIX. The intention was to find a reduced mechanism set to reduce the computational time for a simulation, while still providing accurate results

  7. SiC Nanoparticles Toughened-SiC/MoSi2-SiC Multilayer Functionally Graded Oxidation Protective Coating for Carbon Materials at High Temperatures

    Science.gov (United States)

    Abdollahi, Alireza; Ehsani, Naser; Valefi, Zia; Khalifesoltani, Ali

    2017-05-01

    A SiC nanoparticle toughened-SiC/MoSi2-SiC functionally graded oxidation protective coating on graphite was prepared by reactive melt infiltration (RMI) at 1773 and 1873 K under argon atmosphere. The phase composition and anti-oxidation behavior of the coatings were investigated. The results show that the coating was composed of MoSi2, α-SiC and β-SiC. By the variations of Gibbs free energy (calculated by HSC Chemistry 6.0 software), it could be suggested that the SiC coating formed at low temperatures by solution-reprecipitation mechanism and at high temperatures by gas-phase reactions and solution-reprecipitation mechanisms simultaneously. SiC nanoparticles could improve the oxidation resistance of SiC/MoSi2-SiC multiphase coating. Addition of SiC nanoparticles increases toughness of the coating and prevents spreading of the oxygen diffusion channels in the coating during the oxidation test. The mass loss and oxidation rate of the SiC nanoparticle toughened-SiC/MoSi2-SiC-coated sample after 10-h oxidation at 1773 K were only 1.76% and 0.32 × 10-2 g/cm3/h, respectively.

  8. High-temperature Corrosion Resistance of Composite Coating Prepared by Micro-arc Oxidation Combined with Pack Cementation Aluminizing

    Directory of Open Access Journals (Sweden)

    HUANG Zu-jiang

    2018-01-01

    Full Text Available Al2O3 ceramic film was obtained by micro-arc oxidation (MAO process on Al/C103 specimen, which was prepared by pack cementation aluminizing technology on C103 niobium alloy. With the aid of XRD and SEM equipped with EDS, chemical compositions and microstructures of the composite coatings before and after high-temperature corrosion were analyzed. The behavior and mechanism of the composite coatings in high-temperature oxidation and hot corrosion were also investigated. The results indicate that oxidation mass gain at 1000℃ for 10h of the Al/C103 specimen is 6.98mg/cm2, and it is 2.89mg/cm2 of the MAO/Al/C103 specimen. However, the mass gain of MAO/Al/C103 specimen (57.52mg/cm2 is higher than that of Al/C103 specimen (28.08mg/cm2 after oxidation 20h. After hot corrosion in 75%Na2SO4 and 25%NaCl at 900℃ for 50h, the mass gain of Al/C103 and MAO/Al/C103 specimens are 70.54mg/cm2 and 55.71mg/cm2 respectively, Al2O3 and perovskite NaNbO3 phases are formed on the surface; the diffusion of molten salt is suppressed, due to part of NaNbO3 accumulated in the MAO micropores. Therefore, MAO/Al/C103 specimen exhibits better hot corrosion resistance.

  9. High-Temperature Oxidation-Resistant and Low Coefficient of Thermal Expansion NiAl-Base Bond Coat Developed for a Turbine Blade Application

    Science.gov (United States)

    2003-01-01

    Many critical gas turbine engine components are currently made from Ni-base superalloys that are coated with a thermal barrier coating (TBC). The TBC consists of a ZrO2-based top coat and a bond coat that is used to enhance the bonding between the superalloy substrate and the top coat. MCrAlY alloys (CoCrAlY and NiCrAlY) are currently used as bond coats and are chosen for their very good oxidation resistance. TBC life is frequently limited by the oxidation resistance of the bond coat, along with a thermal expansion mismatch between the metallic bond coat and the ceramic top coat. The aim of this investigation at the NASA Glenn Research Center was to develop a new longer life, higher temperature bond coat by improving both the oxidation resistance and the thermal expansion characteristics of the bond coat. Nickel aluminide (NiAl) has excellent high-temperature oxidation resistance and can sustain a protective Al2O3 scale to longer times and higher temperatures in comparison to MCrAlY alloys. Cryomilling of NiAl results in aluminum nitride (AlN) formation that reduces the coefficient of thermal expansion (CTE) of the alloy and enhances creep strength. Thus, additions of cryomilled NiAl-AlN to CoCrAlY were examined as a potential bond coat. In this work, the composite alloy was investigated as a stand-alone substrate to demonstrate its feasibility prior to actual use as a coating. About 85 percent of prealloyed NiAl and 15 percent of standard commercial CoCrAlY alloys were mixed and cryomilled in an attritor with stainless steel balls used as grinding media. The milling was carried out in the presence of liquid nitrogen. The milled powder was consolidated by hot extrusion or by hot isostatic pressing. From the consolidated material, oxidation coupons, four-point bend, CTE, and tensile specimens were machined. The CTE measurements were made between room temperature and 1000 C in an argon atmosphere. It is shown that the CTE of the NiAl-AlN-CoCrAlY composite bond coat

  10. High temperature oxidation behaviour of nanostructured cermet coatings in a mixed CO2 – O2 environment

    International Nuclear Information System (INIS)

    Farrokhzad, M A; Khan, T I

    2014-01-01

    Nanostructured ceramic-metallic (cermet) coatings composed of nanosized ceramic particles (α-Al 2 O3 and TiO 2 ) dispersed in a nickel matrix were co-electrodeposited and then oxidized at 500°C, 600°C and 700°C in a mixed gas using a Thermo-gravimetric Analysis (TGA) apparatus. The mixed gas was composed of 15% CO 2 , 10% O 2 and 75% N 2 . This research investigates the effects of CO 2 and O 2 partial pressures on time-depended oxidation rates for coatings and compared them to the results from atmospheric oxidation under similar temperatures. The increase in partial pressure of oxygen due to the presence of CO 2 at each tested temperature was calculated and correlated to the oxidation rate of the coatings. The results showed that the presence of CO 2 in the system increased the oxidation rate of cermet coatings when compared to atmospheric oxidation at the same temperature. It was also shown that the increase in the oxidation rate is not the result of CO2 acting as the primary oxidant but as a secondary oxidant which results in an increase of the total partial pressure of oxygen and consequently higher oxidation rates. The WDS and XRD analyses results showed that the presence of nanosized TiO 2 particles in a nickel matrix can improve oxidation behaviour of the coatings by formation of Ni-Ti compounds on oxidizing surface of the coating which was found beneficiary in reducing the oxidation rates for cermet coatings

  11. High temperature oxidation behaviour of nanostructured cermet coatings in amixed CO/sub 2/ - O/sub 2/ environment

    International Nuclear Information System (INIS)

    Farrokhzad, M. A.; Khan, T. I.

    2013-01-01

    Nanostructured ceramic-metallic (cermet) coatings composed of nanosized ceramic particles (alpha-Al /sub 2/O/sub 3/ and TiO/sub 2/) dispersed in a nickel matrix were co-electrodeposited and then oxidized at 500 degree C, 600 degree C and 700 degree C in a mixed gas using a Thermo-gravimetric Analysis (TGA) apparatus. The mixed gas was composed of 15 percentage CO/sub 2/, 10 percentage O/sub 2/ and 75 percentage N/sub 2/. This research investigates the effects of CO/sub 2/ and O/sub 2/ partial pressures on time-depended oxidation rates for coatings and compared them to the results from atmospheric oxidation under similar temperatures. The increase in partial pressure of oxygen due to the presence of CO/sub 2/ at each tested temperature was calculated and correlated to the oxidation rate of the coatings. The results showed that the presence of CO/sub 2/ in the system increased the oxidation rate of cermet coatings when compared to atmospheric oxidation at the same temperature. It was also shown that the increase in the oxidation rate is not the result of CO/sub 2/ acting as the primary oxidant but as a secondary oxidant which results in an increase of the total partial pressure of oxygen and consequently higher oxidation rates. The WDS and XRD analyses results showed that the presence of nanosized TiO/sub 2/ particles in a nickel matrix can improve oxidation behaviour of the coatings by formation of Nu i-Tau i compounds on oxidizing surface of the coating which was found beneficiary in reducing the oxidation rates for cermet coatings. (author)

  12. Study of surface plasma coating of 4340 steel with different microstructure for high temperature use

    International Nuclear Information System (INIS)

    Carrer, Isabela Reis; Abdalla, Antonio Jorge; Barboza, Miguel Justino Ribeiro; Suzuki, Paulo Atsushi

    2010-01-01

    This paper has as main objective the formation of different microstructures by the specific heat treatments and applies the plasma thermochemical treatments to increase surface hardness. These two types of treatments will be evaluated in creep mechanical properties in steel 4340 for aeronautic uses. It will be evaluated, at first, the influence of heat treatments that changes the material microstructure. It was prepared specimen with three kinds of different microstructures (ferritic- perlitic, bainitic and martensitic), have been formed by the different heat treatments. After that, part of specimen will be submitted to plasma coating to evaluate the influence of this kind of surface treatment on creep properties. To better understand the microstructure and the relations between his properties, it was realized microscopic analyses, hardness tests and X-ray diffraction. (author)

  13. High Temperature Behavior of Cr3C2-NiCr Coatings in the Actual Coal-Fired Boiler Environment

    Science.gov (United States)

    Bhatia, Rakesh; Sidhu, Hazoor Singh; Sidhu, Buta Singh

    2015-03-01

    Erosion-corrosion is a serious problem observed in steam-powered electricity generation plants, and industrial waste incinerators. In the present study, four compositions of Cr3C2-(Ni-20Cr) alloy coating powder were deposited by high-velocity oxy-fuel spray technique on T-91 boiler tube steel. The cyclic studies were performed in a coal-fired boiler at 1123 K ± 10 K (850 °C ± 10 °C). X-ray diffraction, scanning electron microscopy/energy dispersive X-ray analysis and elemental mapping analysis techniques were used to analyze the corrosion products. All the coatings deposited on T-91 boiler tube steel imparted hot corrosion resistance. The 65 pctCr3C2 -35 pct (Ni-20Cr)-coated T-91 steel sample performed better than all other coated samples in the given environment.

  14. High-temperature resistant MeCrAlY+Al coatings obtained by ARC-PVD method on Ni Base superalloys

    International Nuclear Information System (INIS)

    Swadzba, L.; Maciejny, A.; Mendala, B.; Supernak, W.

    1999-01-01

    Investigations of obtaining high temperature coatings on the Ni base superalloys by the ARC-PVD method, using exothermic reaction processes between Ni and Al with NiAl intermetallic formation are presented in the article. By the diffusion heating at 1050 o C NiAl high temperature diffusion coating containing 21% at. Al and 50 μm thick was obtained. In the next stage coatings with more complex chemical composition NiCoCrAlY were formed. The two targets were applied for formation of complex NiCoCrAlY coatings. The good consistence between the chemical composition of the targets and the coatings and an uniform distribution of elements in the coatings were shown. Then the surface was covered with aluminium also by the ARC-PVD method. In the vacuum chamber of the equipment a synthesis reaction between NiCoCrAlY and Al with the formation NiAl intermetallics of high Co, Cr, Y content was initiated by the changes in process parameters. The final heat treatment of coatings was conducted in the air and vacuum at 1050 o C. The strong segregation of yttrium in to the oxide scale in the specimens heated in the air was shown. It was possible to obtain NiAl intermetallic phase coatings modified by Co, Cr and Y by the ARC-PVD method. An example of the application of this method for the aircraft engine turbine blades was presented. Method of ARC-PVD gives the possibility chemical composition and high resistance to oxidizing and hot corrosion. (author)

  15. Properties of recent IBAD-MOCVD coated conductors relevant to their high field, low temperature magnet use

    International Nuclear Information System (INIS)

    Braccini, V; Xu, A; Jaroszynski, J; Xin, Y; Larbalestier, D C; Chen, Y; Carota, G; Dackow, J; Kesgin, I; Yao, Y; Guevara, A; Shi, T; Selvamanickam, V

    2011-01-01

    BaZrO 3 (BZO) nanorods are now incorporated into production IBAD-MOCVD coated conductors. Here we compare several examples of both BZO-free and BZO-containing coated conductors using critical current (I c ) characterizations at 4.2 K over their full angular range up to fields of 31 T. We find that BZO nanorods do not produce any c-axis distortion of the critical current density J c (θ) curve at 4.2 K at any field, but also that pinning is nevertheless strongly enhanced compared to the non-BZO conductors. We also find that the tendency of the ab-plane J c (θ) peak to become cusp-like is moderated by BZO and we define a new figure of merit that may be helpful for magnet design-the OADI (off-axis double I c ), which clearly shows that BZO broadens the ab-plane peak and thus raises J c 5 0 -30 0 away from the tape plane, where the most critical approach to I c occurs in many coil designs. We describe some experimental procedures that may make critical current I c tests of these very high current tapes more tractable at 4.2 K, where I c exceeds 1000 A even for 4 mm wide tape with only 1 μm thickness of superconductor. A positive conclusion is that BZO is very beneficial for the J c characteristics at 4.2 K, just as it is at higher temperatures, where the correlated c-axis pinning effects of the nanorods are much more obvious.

  16. Properties of recent IBAD-MOCVD coated conductors relevant to their high field, low temperature magnet use

    Energy Technology Data Exchange (ETDEWEB)

    Braccini, V; Xu, A; Jaroszynski, J; Xin, Y; Larbalestier, D C [Applied Superconductivity Center, National High Magnetic Field Laboratory, 2031 E Paul Dirac Drive, Tallahassee, FL 32310 (United States); Chen, Y; Carota, G; Dackow, J [SuperPower Inc., 450 Duane Avenue, Schenectady, NY 12304 (United States); Kesgin, I; Yao, Y; Guevara, A; Shi, T; Selvamanickam, V, E-mail: braccini@asc.magnet.fsu.edu [Department of Mechanical Engineering and the Texas Center for Superconductivity at the University of Houston, 4800 Calhoun Road, Houston, TX 77204 (United States)

    2011-03-15

    BaZrO{sub 3} (BZO) nanorods are now incorporated into production IBAD-MOCVD coated conductors. Here we compare several examples of both BZO-free and BZO-containing coated conductors using critical current (I{sub c}) characterizations at 4.2 K over their full angular range up to fields of 31 T. We find that BZO nanorods do not produce any c-axis distortion of the critical current density J{sub c}({theta}) curve at 4.2 K at any field, but also that pinning is nevertheless strongly enhanced compared to the non-BZO conductors. We also find that the tendency of the ab-plane J{sub c}({theta}) peak to become cusp-like is moderated by BZO and we define a new figure of merit that may be helpful for magnet design-the OADI (off-axis double I{sub c}), which clearly shows that BZO broadens the ab-plane peak and thus raises J{sub c} 5{sup 0}-30{sup 0} away from the tape plane, where the most critical approach to I{sub c} occurs in many coil designs. We describe some experimental procedures that may make critical current I{sub c} tests of these very high current tapes more tractable at 4.2 K, where I{sub c} exceeds 1000 A even for 4 mm wide tape with only 1 {mu}m thickness of superconductor. A positive conclusion is that BZO is very beneficial for the J{sub c} characteristics at 4.2 K, just as it is at higher temperatures, where the correlated c-axis pinning effects of the nanorods are much more obvious.

  17. Preliminary Evaluation of PS300: A New Self-Lubricating High Temperature Composite Coating for Use to 800 C

    Science.gov (United States)

    Dellacorte, C.; Edmonds, B. J.

    1995-01-01

    This paper introduces PS300, a plasma sprayed, self-lubricating composite coating for use in sliding contacts at temperatures to 800 C. PS300 is a metal bonded chrome oxide coating with silver and BaF2/CaF2 eutectic solid lubricant additives. PS300 is similar to PS200, a chromium carbide based coating, which is currently being investigated for a variety of tribological applications. In pin-on-disk testing up to 650 C, PS300 exhibited comparable friction and wear properties to PS200. The PS300 matrix, which is predominantly chromium oxide rather than chromium carbide, does not require diamond grinding and polishes readily with silicon carbide abrasives greatly reducing manufacturing costs compared to PS200. It is anticipated that PS300 has potential for sliding bearing and seal applications in both aerospace and general industry.

  18. Femtosecond laser induced breakdown spectroscopy of silver within surrogate high temperature gas reactor fuel coated particles

    CSIR Research Space (South Africa)

    Roberts, DE

    2010-11-01

    Full Text Available of the density ratios using Eq. (5) and Fig. 12. The electron temperature was measured from the relative intensity of two spectral lines assuming LTE [31]: IA IB = ?BgAAA ?AgBAB exp??�EABkTe ?: ?6? From Eq. (6), the percentage error in the estimate... of Te is the percentage error in measuring the intensity ratio multiplied by kTe/�E so the larger �EAB the better (except insofar as it is then more dif�cult to satisfy the LTE criterion, as seen below). Silver is a convenient element...

  19. Microstructure and wear behaviors of laser clad NiCr/Cr3C2-WS2 high temperature self-lubricating wear-resistant composite coating

    Science.gov (United States)

    Yang, Mao-Sheng; Liu, Xiu-Bo; Fan, Ji-Wei; He, Xiang-Ming; Shi, Shi-Hong; Fu, Ge-Yan; Wang, Ming-Di; Chen, Shu-Fa

    2012-02-01

    The high temperature self-lubricating wear-resistant NiCr/Cr3C2-30%WS2 coating and wear-resistant NiCr/Cr3C2 coating were fabricated on 0Cr18Ni9 austenitic stainless steel by laser cladding. Phase constitutions and microstructures were investigated, and the tribological properties were evaluated using a ball-on-disc wear tester under dry sliding condition at room-temperature (17 °C), 300 °C and 600 °C, respectively. Results indicated that the laser clad NiCr/Cr3C2 coating consisted of Cr7C3 primary phase and γ-(Fe,Ni)/Cr7C3 eutectic colony, while the coating added with WS2 was mainly composed of Cr7C3 and (Cr,W)C carbides, with the lubricating WS2 and CrS sulfides as the minor phases. The wear tests showed that the friction coefficients of two coatings both decrease with the increasing temperature, while the both wear rates increase. The friction coefficient of laser clad NiCr/Cr3C2-30%WS2 is lower than the coating without WS2 whatever at room-temperature, 300 °C, 600 °C, but its wear rate is only lower at 300 °C. It is considered that the laser clad NiCr/Cr3C2-30%WS2 composite coating has good combination of anti-wear and friction-reducing capabilities at room-temperature up to 300 °C.

  20. Innovative Processing Methods for the Affordable Manufacture of Multifunctional High Temperature Coatings, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Research is proposed to investigate the feasibility of using advanced manufacturing techniques to enable the affordable application of multi-functional high...

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

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Narinder [Semiconductor Materials and Device Laboratory, Department of Semiconductor Science, Dongguk University-Seoul, Seoul 100715 (Korea, Republic of); Kumar, Manoj [School of Mechanical, Materials & Energy Engineering, Indian Institute of Technology Ropar, Rupnagar, Punjab (India); Sharma, Sanjeev K.; Kim, Deuk Young [Semiconductor Materials and Device Laboratory, Department of Semiconductor Science, Dongguk University-Seoul, Seoul 100715 (Korea, Republic of); Kumar, S.; Chavan, N.M.; Joshi, S.V. [International Advanced Research Centre for Powder Metallurgy & New Materials (ARCI), Hyderabad 500005 (India); Singh, Narinder [Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab (India); Singh, Harpreet, E-mail: harpreetsingh@iitrpr.ac.in [School of Mechanical, Materials & Energy Engineering, Indian Institute of Technology Ropar, Rupnagar, Punjab (India)

    2015-02-15

    Highlights: • A presynthesized Ni-20Cr nanocrystalline powder was successfully deposited on T22 and SA 516 boilers steels using cold spray process. • The coatings are observed to have more than 2-folds microhardness in comparison with the base steels. • The coating was successful in reducing the weight gain of T22 and SA 516 steel by 71% and 94%. - Abstract: 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. The behavior of ZrO2/20%Y2O3 and Al2O3 coatings deposited on aluminum alloys at high temperature regime

    Science.gov (United States)

    Pintilei, G. L.; Crismaru, V. I.; Abrudeanu, M.; Munteanu, C.; Baciu, E. R.; Istrate, B.; Basescu, N.

    2015-10-01

    Aluminum alloy present numerous advantages like lightness, high specific strength and diversity which recommend them to a high number of applications from different fields. In extreme environments the protection of aluminum alloys is difficult and requires a high number of requirements like high temperature resistance, thermal fatigue resistance, corrosion fatigue resistance and galvanic corrosion resistance. To obtain these characteristics coatings can be applied to the surfaces so they can enhance the mechanical and chemical properties of the parts. In this paper two coatings were considered for deposition on an AA2024 aluminum alloy, ZrO2/20%Y2O3 and Al2O3. To obtain a better adherence of the coating to the base material an additional bond layer of NiCr is used. Both the coatings and bond layer were deposited by atmospheric plasma spraying on the samples. The samples were subjected to a temperature of 500 °C and after that slowly cooled to room temperature. The samples were analyzed by electron microscopy and X-ray diffraction to determine the morphological and phase changes that occurred during the temperature exposure. To determine the stress level in the parts due to thermal expansion a finite element analysis was performed in the same conditions as the tests.

  3. Microstructure and high temperature oxidation resistance of Ti-Ni gradient coating on TA2 titanium alloy fabricated by laser cladding

    Science.gov (United States)

    Liu, Fencheng; Mao, Yuqing; Lin, Xin; Zhou, Baosheng; Qian, Tao

    2016-09-01

    To improve the high temperature oxidation resistance of TA2 titanium alloy, a gradient Ni-Ti coating was laser cladded on the surface of the TA2 titanium alloy substrate, and the microstructure and oxidation behavior of the laser cladded coating were investigated experimentally. The gradient coating with a thickness of about 420-490 μm contains two different layers, e.g. a bright layer with coarse equiaxed grain and a dark layer with fine and columnar dendrites, and a transition layer with a thickness of about 10 μm exists between the substrate and the cladded coating. NiTi, NiTi2 and Ni3Ti intermetallic compounds are the main constructive phases of the laser cladded coating. The appearance of these phases enhances the microhardness, and the dense structure of the coating improves its oxidation resistance. The solidification procedure of the gradient coating is analyzed and different kinds of solidification processes occur due to the heat dissipation during the laser cladding process.

  4. High Temperature Oxidation Behavior of gamma-Ni+gamma'-Ni3Al Alloys and Coatings Modified with Pt and Reactive Elements

    Energy Technology Data Exchange (ETDEWEB)

    Mu, Nan [Iowa State Univ., Ames, IA (United States)

    2007-12-01

    Materials for high-pressure turbine blades must be able to operate in the high-temperature gases (above 1000 C) emerging from the combustion chamber. Accordingly, the development of nickel-based superalloys has been constantly motivated by the need to have improved engine efficiency, reliability and service lifetime under the harsh conditions imposed by the turbine environment. However, the melting point of nickel (1455 C) provides a natural ceiling for the temperature capability of nickel-based superalloys. Thus, surface-engineered turbine components with modified diffusion coatings and overlay coatings are used. Theses coatings are capable of forming a compact and adherent oxide scale, which greatly impedes the further transport of reactants between the high-temperature gases and the underlying metal and thus reducing attack by the atmosphere. Typically, these coatings contain β-NiAl as a principal constituent phase in order to have sufficient aluminum content to form an Al2O3 scale at elevated temperatures. The drawbacks to the currently-used {beta}-based coatings, such as phase instabilities, associated stresses induced by such phase instabilities, and extensive coating/substrate interdiffusion, are major motivations in this study to seek next-generation coatings. The high-temperature oxidation resistance of novel Pt + Hf-modified γ-Ni + γ-Ni3Al-based alloys and coatings were investigated in this study. Both early-stage and 4-days isothermal oxidation behavior of single-phase γ-Ni and γ'-Ni3Al alloys were assessed by examining the weight changes, oxide-scale structures, and elemental concentration profiles through the scales and subsurface alloy regions. It was found that Pt promotes Al2O3 formation by suppressing the NiO growth on both γ-Ni and γ'Ni3Al single-phase alloys. This effect increases with increasing Pt content. Moreover, Pt exhibits this effect even at

  5. IPN Polysiloxane-Epoxy Resin for High Temperature Coatings: Structure Effects on Layer Performance after 450 °C Treatment

    Directory of Open Access Journals (Sweden)

    Simone Giaveri

    2017-11-01

    Full Text Available Coatings for high temperatures (HT > 400 °C are obtained from interpenetrating polymer network (IPN binders formed by simultaneous polymerization of silicone and epoxide pre-polymers. A ceramic layer; mainly composed of silica and fillers; remains on the metal surface after a thermal treatment at 450 °C. The layer adhesion and the inorganic filler’s distribution have been investigated by, firstly, exchanging the organic substituents (methyl and phenyl of the silicone chains and, secondly, by adding conductive graphene nanoplatelets with the aim to assure a uniform distribution of heat during the thermal treatment. The results are evidence that different substituent ratios affect the polymer initial layout. The adhesion tests of paint formulations are analysed and were related to instrumental analyses performed using glow discharge optical emission spectroscopy (GDOES; thermal analyses (TG/DTA and DSC; electron microscopy with energy dispersive X-ray analysis (SEM-EDX. A greater resistance to powdering using phenyl groups instead of methyl ones; and an improved distribution of fillers due to graphene nanoplatelet addition; is evidenced.

  6. Development and characterization of laser clad high temperature self-lubricating wear resistant composite coatings on Ti–6Al–4V alloy

    International Nuclear Information System (INIS)

    Liu, Xiu-Bo; Meng, Xiang-Jun; Liu, Hai-Qing; Shi, Gao-Lian; Wu, Shao-Hua; Sun, Cheng-Feng; Wang, Ming-Di; Qi, Long-Hao

    2014-01-01

    Highlights: • A novel high temperature self-lubricating anti-wear composite coating was fabricated. • Reinforced carbides as well as self-lubricating sulfides were in situ synthesized. • Microhardness of the Ti–6Al–4V substrate was significantly improved. • Friction coefficient and wear rate of the composite coating were greatly reduced. - Abstract: To enhance the wear resistance and friction-reducing capability of titanium alloy, a process of laser cladding γ-NiCrAlTi/TiC + TiWC 2 /CrS + Ti 2 CS coatings on Ti–6Al–4V alloy substrate with preplaced NiCr/Cr 3 C 2 –WS 2 mixed powders was studied. A novel coating without cracks and few pores was obtained in a proper laser processing. The composition and microstructure of the fabricated coating were examined by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) techniques, and tribological properties were evaluated using a ball-on-disc tribometer under dry sliding wear test conditions at 20 °C (room-temperature), 300 °C, 600 °C, respectively. The results show that the coating has unique microstructure consisting of α-Ti, TiC, TiWC 2 , γ-NiCrAlTi, Ti 2 CS and CrS phases. Average microhardness of the composite coating is 1005 HV 0.2 , which is about 3-factor higher than that of Ti–6Al–4V substrate (360 HV 0.2 ). The friction coefficient and wear rate of the coating are greatly decreased due to the combined effects of the dominating anti-wear capabilities of reinforced TiC and TiWC 2 carbides and the CrS and Ti 2 CS sulfides which have excellent self-lubricating property

  7. A high-throughput investigation of Fe-Cr-Al as a novel high-temperature coating for nuclear cladding materials.

    Science.gov (United States)

    Bunn, Jonathan Kenneth; Fang, Randy L; Albing, Mark R; Mehta, Apurva; Kramer, Matthew J; Besser, Matthew F; Hattrick-Simpers, Jason R

    2015-07-10

    High-temperature alloy coatings that can resist oxidation are urgently needed as nuclear cladding materials to mitigate the danger of hydrogen explosions during meltdown. Here we apply a combination of computationally guided materials synthesis, high-throughput structural characterization and data analysis tools to investigate the feasibility of coatings from the Fe–Cr–Al alloy system. Composition-spread samples were synthesized to cover the region of the phase diagram previous bulk studies have identified as forming protective oxides. The metallurgical and oxide phase evolution were studied via in situ synchrotron glancing incidence x-ray diffraction at temperatures up to 690 K. A composition region with an Al concentration greater than 3.08 at%, and between 20.0 at% and 32.9 at% Cr showed the least overall oxide growth. Subsequently, a series of samples were deposited on stubs and their oxidation behavior at 1373 K was observed. The continued presence of a passivating oxide was confirmed in this region over a period of 6 h.

  8. Alternative waste form development - low-temperature pyrolytic carbon coatings

    International Nuclear Information System (INIS)

    Oma, K.H.; Rusin, J.M.; Kidd, R.W.; Browning, M.F.

    1981-01-01

    Although several chemical vapor deposition (CVD) - coated waste forms have been successfully produced, some major disadvantages associated with the high-temperature fluidized-bed CVD coating process exist. To overcome these disadvantages, the Pacific Northwest Laboratory has initiated the development of a pyrolytic carbon CVD coating system to coat large waste-form particles at temperatures ranging from 400 to 500/degree/C. This relatively simple system has been used to coat kilogram quantities of simulated waste-glass marbles. Further development of this system could result in a viable process to coat bulk quantities of both glass and ceramic waste forms. This paper discusses various aspects of the development work, including coating techniques, parametric study, and coater equipment. 10 refs

  9. Preparation of Platinum (Pt) Counter Electrode Coated by Electrochemical Technique at High Temperature for Dye-sensitized Solar Cell (DSSC) Application

    Science.gov (United States)

    Ponken, Tanachai; Tagsin, Kamonlapron; Suwannakhun, Chuleerat; Luecha, Jakkrit; Choawunklang, Wijit

    2017-09-01

    Pt counter electrode was coated by electrochemical method. Electrolyte solution was synthesized by platinum (IV) choloride (PtCl4) powder dissolved in hydrochloric acid solution. Pt films were deposited on the FTO substrate. Deposition time of 10, 30 and 60 minutes, the coating current of 5, 10, 15 and 20 mA and electrolyte solution temperatures for Pt layer synthesis of 25, 30 and 40°C were varied. Surface morphology and optical properties was analyzed by digital microscopic and UV-vis spectrophotometer. Pt films exhibit uniform surface area highly for all the conditions of coating current in the deposition time of 30 and 40 minutes at 40°C. Transmittance values of Pt films deposited on FTO substrate has approximately of 5 to 50 % show that occur high reflection corresponding to dye molecule absorption increases. DSSC device was fabricated from the TiO2 standard and immersed in dye N719 for 24 hours. Efficiency was measured by solar simulator. Efficiency value obtains as high as 5.91 % for the coating current, deposition time and solution temperature of 15 mA, 30 minutes and 40°C. Summary, influence of temperature effects efficiency increasing. Pt counter electrode can be prepared easily and the suitable usefully for DSSC.

  10. High vacuum tribology of polycrystalline diamond coatings

    Indian Academy of Sciences (India)

    Polycrystalline diamond coatings; hot filament CVD; high vacuum tribology. 1. Introduction .... is a characteristic of graphite. We mark the (diamond ... coefficient of friction due to changes in substrate temperature. The average coefficient of.

  11. MOCVD coating deposition of yttrium stabilized zirconia as backing for high-temperature superconductors on flexible substrates

    International Nuclear Information System (INIS)

    Jakschik, F.; Berger, W.; Seifert, L.; Nowick, W.; Leonhardt, G.

    1993-01-01

    The coating of carbon fibers with YSZ by means of the presented MOCVD process showed that in the bundle at temperatures between 500 - 600 C the coating thickness drops toward the center of the bundle. Sufficient homogeneity can be achieved only when the precipitation rate is selected slow enough to prevent the bundle edge from closing, or when the bundle is spread sufficiently open. The layers are on one hand ZrO 2 with incorporated carbon and on the other hand yttrium stabilized ZrO 2 with incorporated carbon. In both cases exclusively the cubic phase of the oxide was detected. The morphology of layers revealed only slight roughness with incorporation of relatively large nodules consisting of YSZ, caused by homogeneous gas phase reactions which are to be prevented. (orig.) [de

  12. Core/Shell Structure of TiO2-Coated MWCNTs for Thermal Protection for High-Temperature Processing of Metal Matrix Composites

    Directory of Open Access Journals (Sweden)

    Laura Angélica Ardila Rodriguez

    2018-01-01

    Full Text Available The production of metal matrix composites with elevated mechanical properties depends largely on the reinforcing phase properties. Due to the poor oxidation resistance of multiwalled carbon nanotubes (MWCNTs as well as their high reactivity with molten metal, the processing conditions for the production of MWCNT-reinforced metal matrix composites may be an obstacle to their successful use as reinforcement. Coating MWCNTs with a ceramic material that acts as a thermal protection would be an alternative to improve oxidation stability. In this work, MWCNTs previously functionalized were coated with titanium dioxide (TiO2 layers of different thicknesses, producing a core-shell structure. Heat treatments at three different temperatures (500°C, 750°C, and 1000°C were performed on coated nanotubes in order to form a stable metal oxide structure. The MWCNT/TiO2 hybrids produced were evaluated in terms of thermal stability. Thermogravimetric analysis (TGA, X-ray diffraction (XRD, scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, Raman spectroscopy (RS, and X-ray photoelectron spectroscopy (XPS were performed in order to investigate TiO2-coated MWCNT structure and thermal stability under oxidative atmosphere. It was found that the thermal stability of the TiO2-coated MWCNTs was dependent of the TiO2 layer morphology that in turn depends on the heat treatment temperature.

  13. High efficiency turbine blade coatings

    Energy Technology Data Exchange (ETDEWEB)

    Youchison, Dennis L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gallis, Michail A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-06-01

    The development of advanced thermal barrier coatings (TBCs) of yttria stabilized zirconia (YSZ) that exhibit lower thermal conductivity through better control of electron beam - physical vapor deposition (EB-PVD) processing is of prime interest to both the aerospace and power industries. This report summarizes the work performed under a two-year Lab-Directed Research and Development (LDRD) project (38664) to produce lower thermal conductivity, graded-layer thermal barrier coatings for turbine blades in an effort to increase the efficiency of high temperature gas turbines. This project was sponsored by the Nuclear Fuel Cycle Investment Area. Therefore, particular importance was given to the processing of the large blades required for industrial gas turbines proposed for use in the Brayton cycle of nuclear plants powered by high temperature gas-cooled reactors (HTGRs). During this modest (~1 full-time equivalent (FTE)) project, the processing technology was developed to create graded TBCs by coupling ion beam-assisted deposition (IBAD) with substrate pivoting in the alumina-YSZ system. The Electron Beam - 1200 kW (EB-1200) PVD system was used to deposit a variety of TBC coatings with micron layered microstructures and reduced thermal conductivity below 1.5 W/m.K. The use of IBAD produced fully stoichiometric coatings at a reduced substrate temperature of 600°C and a reduced oxygen background pressure of 0.1 Pa. IBAD was also used to successfully demonstrate the transitioning of amorphous PVD-deposited alumina to the -phase alumina required as an oxygen diffusion barrier and for good adhesion to the substrate Ni2Al3 bondcoat. This process replaces the time consuming thermally grown oxide formation required before the YSZ deposition. In addition to the process technology, Direct Simulation Monte Carlo plume modeling and spectroscopic characterization of the PVD plumes were performed. The project consisted of five tasks. These included the

  14. High temperature niobium alloys

    International Nuclear Information System (INIS)

    Wojcik, C.C.

    1991-01-01

    Niobium alloys are currently being used in various high temperature applications such as rocket propulsion, turbine engines and lighting systems. This paper presents an overview of the various commercial niobium alloys, including basic manufacturing processes, properties and applications. Current activities for new applications include powder metallurgy, coating development and fabrication of advanced porous structures for lithium cooled heat pipes

  15. High temperature corrosion of thermally sprayed NiCr- and amorphous Fe-based coatings covered with a KCl-K{sub 2}SO{sub 4} salt

    Energy Technology Data Exchange (ETDEWEB)

    Varis, T.; Suhonen, T.; Tuurna, S.; Ruusuvuori, K.; Holmstroem, S.; Salonen, J. [VTT, Espoo (Finland); Bankiewicz, D.; Yrjas, P. [Aabo Akademi Univ., Turku (Finland)

    2010-07-01

    New process conditions due to the requirement of higher efficiency together with the use of high-chlorine and alkali containing fuels such as biomass and waste fuels for heat and electricity production will challenge the resistance and life of tube materials. In conventional materials the addition of alloying elements to increase the corrosion resistance in aggressive combustion conditions increases costs relatively rapidly. Thermally sprayed coating offer promising, effective, flexible and cost efficient solutions to fulfill the material needs for the future. Some heat exchanger design alteractions before global commercialization have to be overcome, though. High temperature corrosion in combustion plants can occur by a variety of mechanisms including passive scale degradation with subsequent rapid scaling, loss of adhesion and scale detachment, attack by melted or partly melted deposits via fluxing reactions and intergranular-/interlamellar corrosion. A generally accepted model of the ''active oxidation'' attributes the responsibility for inducing corrosion to chlorine. The active oxidation mechanism plays a key role in the thermally sprayed coatings due to their unique lamellar structure. In this study, the corrosion behaviour of NiCr (HVOF and Wire Arc), amorphous Fe-based, and Fe13Cr (Wire Arc) thermally sprayed coatings, were tested in the laboratory under simplified biomass combustion conditions. The tests were carried out by using a KCl-K{sub 2}SO{sub 4} salt mixture as a synthetic biomass ash, which was placed on the materials and then heat treated for one week (168h) at two different temperatures (550{sup 0}C and 600 C) and in two different gas atmospheres (air and air+30%H{sub 2}O). After the exposures, the metallographic cross sections of the coatings were studied with SEM/EDX analyzer. The results showed that the coatings behaved relatively well at the lower test temperature while critical corrosion through the lamella boundaries

  16. High-temperature resistant, thermally sprayed diffusion barrier coatings on CFC lightweight materials; Hochtemperaturbestaendige, thermisch gespritzte Diffusionsbarriereschichten auf CFC-Leichtbauchargiergestellen

    Energy Technology Data Exchange (ETDEWEB)

    Drehmann, Rico; Rupprecht, Christian; Wielage, Bernhard; Lampke, Thomas [Technische Univ. Chemnitz (Germany). Inst. fuer Werkstoffwissenschaft und Werkstofftechnik (IWW); Gilbert, Maria; Uhlig, Volker; Trimis, Dimosthenis [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Waermetechnik und Thermodynamik (IWTT); Heuer, Volker [ALD Vacuum Technologies GmbH, Hanau (Germany)

    2013-03-15

    In heat treating processes as well as in high temperature brazing processes, charge carriers enable the positioning and transport of work pieces. Recently, charge carriers consisting of graphite or carbon fibre reinforced carbon (CFC) are used. The main disadvantage of charge carriers based on CFC is the undesirable carburization of the overlying components due to diffusion processes. Under this aspect, thermally sprayed coatings are applied on CFC and tested with respect to their suitability as a high-temperature diffusion barrier. The ceramic powders aluminium oxide, aluminium oxide/chromium oxide, aluminium oxide/titanium oxide and zirconium oxide/yttrium oxide are used as a coating material which is processed by means of the powder flame spraying as well as atmospheric plasma spraying. Molybdenum and silicon carbide are used as an adhesive layer. The coating materials aluminium oxide and aluminium oxide/chromium oxide on siliconized CFC presented excellent results. This supplies a large potential of application for thermally sprayed ceramic coatings on carbon-based lightweight materials.

  17. Tailoring a High Temperature Corrosion Resistant FeNiCrAl for Oxy-Combustion Application by Thermal Spray Coating and HIP

    Directory of Open Access Journals (Sweden)

    Jarkko Metsäjoki

    2015-10-01

    Full Text Available Oxy-fuel combustion combined with CCS (carbon capture and storage aims to decrease CO2 emissions in energy production using fossil fuels. Oxygen firing changes power plant boiler conditions compared to conventional firing. Higher material temperatures and harsher and more variable environmental conditions cause new degradation processes that are inadequately understood at the moment. In this study, an Fe-Ni-Cr-Al alloy was developed based on thermodynamic simulations. The chosen composition was manufactured as powder by gas atomization. The powder was sieved into two fractions: The finer was used to produce thermal spray coatings by high velocity oxy-fuel (HVOF and the coarser to manufacture bulk specimens by hot isostatic pressing (HIP. The high temperature corrosion properties of the manufactured FeNiCrAl coating and bulk material were tested in laboratory conditions simulating oxy-combustion. The manufacturing methods and the results of high temperature corrosion performance are presented. The corrosion performance of the coating was on average between the bulk steel references Sanicro 25 and TP347HFG.

  18. Fission Product Release Behavior of Individual Coated Fuel Particles for High-Temperature Gas-Cooled Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Minato, Kazuo [Japan Atomic Energy Research Institute (Japan); Sawa, Kazuhiro [Japan Atomic Energy Research Institute (Japan); Koya, Toshio [Japan Atomic Energy Research Institute (Japan); Tomita, Takeshi [Japan Atomic Energy Research Institute (Japan); Ishikawa, Akiyoshi [Japan Atomic Energy Research Institute (Japan); Baldwin, Charles A; Gabbard, William Alexander [Oak Ridge National Laboratory (United States); Malone, Charlie M [Oak Ridge National Laboratory (United States)

    2000-07-15

    Postirradiation heating tests of TRISO-coated UO{sub 2} particles at 1700 and 1800degC were performed to understand fission product release behavior at accident temperatures. The inventory measurements of the individual particles were carried out before and after the heating tests with gamma-ray spectrometry to study the behavior of the individual particles. The time-dependent release behavior of {sup 85}Kr, {sup 110m}Ag, {sup 134}Cs, {sup 137}Cs, and {sup 154}Eu were obtained with on-line measurements of fission gas release and intermittent measurements of metallic fission product release during the heating tests. The inventory measurements of the individual particles revealed that fission product release behavior of the individual particles was not uniform, and large particle-to-particle variations in the release behavior of {sup 110m}Ag, {sup 134}Cs, {sup 137}Cs, and {sup 154}Eu were found. X-ray microradiography and ceramography showed that the variations could not be explained by only the presence or absence of cracks in the SiC coating layer. The SiC degradation may have been related to the variations.

  19. Fission Product Release Behavior of Individual Coated Fuel Particles for High-Temperature Gas-Cooled Reactors

    International Nuclear Information System (INIS)

    Minato, Kazuo; Sawa, Kazuhiro; Koya, Toshio; Tomita, Takeshi; Ishikawa, Akiyoshi; Baldwin, Charles A.; Gabbard, William Alexander; Malone, Charlie M.

    2000-01-01

    Postirradiation heating tests of TRISO-coated UO 2 particles at 1700 and 1800degC were performed to understand fission product release behavior at accident temperatures. The inventory measurements of the individual particles were carried out before and after the heating tests with gamma-ray spectrometry to study the behavior of the individual particles. The time-dependent release behavior of 85 Kr, 110m Ag, 134 Cs, 137 Cs, and 154 Eu were obtained with on-line measurements of fission gas release and intermittent measurements of metallic fission product release during the heating tests. The inventory measurements of the individual particles revealed that fission product release behavior of the individual particles was not uniform, and large particle-to-particle variations in the release behavior of 110m Ag, 134 Cs, 137 Cs, and 154 Eu were found. X-ray microradiography and ceramography showed that the variations could not be explained by only the presence or absence of cracks in the SiC coating layer. The SiC degradation may have been related to the variations

  20. High temperature coatings from post processing Fe-based chips and Ni-based alloys as a solution for critical raw materials

    Science.gov (United States)

    Dudziak, T.; Olbrycht, A.; Polkowska, A.; Boron, L.; Skierski, P.; Wypych, A.; Ambroziak, A.; Krezel, A.

    2018-03-01

    Due to shortage of natural resources worldwide, it is a need to develop innovative technologies, to save natural resources and secure Critical Raw Materials (CRM). On the other hand, these new technologies should move forward materials engineering in order to develop better materials for extreme conditions. One way to develop new materials is to use post processing chips of austenitic steels (i.e. 304L stainless steel: 18/10 Cr/Ni) and other materials such as Ni-based alloy with high Cr content. In this work, the results of the preliminary study on the High Velocity Oxy Fuel (HVOF) coatings developed from 304L stainless steel chips and Haynes® 282® Ni- based alloys are shown. The study obeys development of the powder for HVOF technology. The produced coatings were exposed at high temperature at 500 and 700 °C for 100 and 300 hours respectively to assess corrosion behaviour.

  1. Angular dependence of J{sub c} for YBCO coated conductors at low temperature and very high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Xu, A; Jaroszynski, J J; Kametani, F; Chen, Z; Larbalestier, D C [Applied Superconductivity Center, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Viouchkov, Y L [National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Chen, Y; Xie, Y; Selvamanickam, V, E-mail: aixiaxu@asc.magnet.fsu.ed [SuperPower Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States)

    2010-01-15

    We present very high field angle dependent critical current density (J{sub c}) data for three recently obtained YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) coated conductors used in the construction of high field solenoids. We find that strongly correlated pins, such as BaZrO{sub 3} (BZO) nanorods, while yielding strong c-axis peaks at 77 K, produce almost no measurable contribution at 4 K. Raising the field from <5 to 30 T at 4 K causes a marked transition from a Ginzburg-Landau-like J{sub c}({theta}) at low fields to a marked cusp-like behavior at high fields. Transmission electron micrographs show that all samples contain a high density of stacking faults which strengthen the plane correlated pinning parallel to the ab planes produced by the intrinsic ab-plane pinning of the Cu-O charge reservoir layers.

  2. Facile and Low-Temperature Fabrication of Thermochromic Cr2O3/VO2 Smart Coatings: Enhanced Solar Modulation Ability, High Luminous Transmittance and UV-Shielding Function.

    Science.gov (United States)

    Chang, Tianci; Cao, Xun; Li, Ning; Long, Shiwei; Gao, Xiang; Dedon, Liv R; Sun, Guangyao; Luo, Hongjie; Jin, Ping

    2017-08-09

    In the pursuit of energy efficient materials, vanadium dioxide (VO 2 ) based smart coatings have gained much attention in recent years. For smart window applications, VO 2 thin films should be fabricated at low temperature to reduce the cost in commercial fabrication and solve compatibility problems. Meanwhile, thermochromic performance with high luminous transmittance and solar modulation ability, as well as effective UV shielding function has become the most important developing strategy for ideal smart windows. In this work, facile Cr 2 O 3 /VO 2 bilayer coatings on quartz glasses were designed and fabricated by magnetron sputtering at low temperatures ranging from 250 to 350 °C as compared with typical high growth temperatures (>450 °C). The bottom Cr 2 O 3 layer not only provides a structural template for the growth of VO 2 (R), but also serves as an antireflection layer for improving the luminous transmittance. It was found that the deposition of Cr 2 O 3 layer resulted in a dramatic enhancement of the solar modulation ability (56.4%) and improvement of luminous transmittance (26.4%) when compared to single-layer VO 2 coating. According to optical measurements, the Cr 2 O 3 /VO 2 bilayer structure exhibits excellent optical performances with an enhanced solar modulation ability (ΔT sol = 12.2%) and a high luminous transmittance (T lum,lt = 46.0%), which makes a good balance between ΔT sol and T lum for smart windows applications. As for UV-shielding properties, more than 95.8% UV radiation (250-400 nm) can be blocked out by the Cr 2 O 3 /VO 2 structure. In addition, the visualized energy-efficient effect was modeled by heating a beaker of water using infrared imaging method with/without a Cr 2 O 3 /VO 2 coating glass.

  3. The Influence of Chemical Alloying on the High Temperature Wear Resistance of H-Free DLC Coatings

    NARCIS (Netherlands)

    Galvan, D.; Pei, Y.T.; Hosson, J.T.M. De; Cavaleiro, A.; Chandra, T; Tsuzaki, K; Militzer, M; Ravindran, C

    2007-01-01

    A commercial RF-sputtering deposition rig was employed to deposit H-free diamond-like carbon (DLC) coatings. The influence of alloying elements such as Ti and Si on the structure, mechanical and tribological properties of the coatings was investigated. The coating was observed in cross section and

  4. Low Conductive Thermal Barrier Coatings Produced by Ion Beam Assisted EB-PVD with Controlled Porosity, Microstructure Refinement and Alloying Additions for High Temperature Applications

    Science.gov (United States)

    Wolfe, Douglas E.; Singh, Jogender

    2005-01-01

    Various advanced Hafnia-based thermal barrier coatings (TBC) were applied on nickel-based superalloy coupons by electron beam physical vapor deposition. In addition, microstructural modifications to the coating material were made in an effort to reduce the thermal conductivity of the coating materials. Various processing parameters and coating system modifications were made in order to deposit the alloyed TBC with the desired microstructure and thus coating performance, some of which include applying coatings at substrate temperatures of 1150 C on both PtAl and CoNiCrAlY bond coated samples, as well as using 8YSZ as a bond layer. In addition, various characterization techniques including thermal cyclic tests, scanning electron microscopy, x-ray diffraction, thermal conductivity, and reflectivity measurements were performed. Although the coating microstructure was never fully optimized due to funding being cut short, significant reductions in thermal conductivity were accomplished through both chemistry changes (composition) and microstructural modifications.

  5. Effects of a Mixed Zone on TGO Displacement Instabilities of Thermal Barrier Coatings at High Temperature in Gas-Cooled Fast Reactors

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2016-01-01

    Full Text Available Thermally grown oxide (TGO, commonly pure α-Al2O3, formed on protective coatings acts as an insulation barrier shielding cooled reactors from high temperatures in nuclear energy systems. Mixed zone (MZ oxide often grows at the interface between the alumina layer and top coat in thermal barrier coatings (TBCs at high temperature dwell times accompanied by the formation of alumina. The newly formed MZ destroys interface integrity and significantly affects the displacement instabilities of TGO. In this work, a finite element model based on material property changes was constructed to investigate the effects of MZ on the displacement instabilities of TGO. MZ formation was simulated by gradually changing the metal material properties into MZ upon thermal cycling. Quantitative data show that MZ formation induces an enormous stress in TGO, resulting in a sharp change of displacement compared to the alumina layer. The displacement instability increases with an increase in the MZ growth rate, growth strain, and thickness. Thus, the formation of a MZ accelerates the failure of TBCs, which is in agreement with previous experimental observations. These results provide data for the understanding of TBC failure mechanisms associated with MZ formation and of how to prolong TBC working life.

  6. Bimetallic low thermal-expansion panels of Co-base and silicide-coated Nb-base alloys for high-temperature structural applications

    International Nuclear Information System (INIS)

    Rhein, R.K.; Novak, M.D.; Levi, C.G.; Pollock, T.M.

    2011-01-01

    Research highlights: → Low net thermal expansion bimetallic structural lattice constructed. → Temperatures on the order of 1000 deg. C reached. → Improved silicide coating for niobium alloy developed. - Abstract: The fabrication and high temperature performance of low thermal expansion bimetallic lattices composed of Co-base and Nb-base alloys have been investigated. A 2D sheet lattice with a coefficient of thermal expansion (CTE) lower than the constituent materials of construction was designed for thermal cycling to 1000 deg. C with the use of elastic-plastic finite element analyses. The low CTE lattice consisted of a continuous network of the Nb-base alloy C-103 with inserts of high CTE Co-base alloy Haynes 188. A new coating approach wherein submicron alumina particles were incorporated into (Nb, Cr, Fe) silicide coatings was employed for oxidation protection of the Nb-base alloy. Thermal gravimetric analysis results indicate that the addition of submicron alumina particles reduced the oxidative mass gain by a factor of four during thermal cycling, increasing lifetime. Bimetallic cells with net expansion of 6 x 10 -6 /deg. C and 1 x 10 -6 /deg. C at 1000 deg. C were demonstrated and their measured thermal expansion characteristics were consistent with analytical models and finite element analysis predictions.

  7. High Temperature Oxidation of Nickel-based Cermet Coatings Composed of Al2O3 and TiO2 Nanosized Particles

    Science.gov (United States)

    Farrokhzad, M. A.; Khan, T. I.

    2014-09-01

    New technological challenges in oil production require materials that can resist high temperature oxidation. In-Situ Combustion (ISC) oil production technique is a new method that uses injection of air and ignition techniques to reduce the viscosity of bitumen in a reservoir and as a result crude bitumen can be produced and extracted from the reservoir. During the in-situ combustion process, production pipes and other mechanical components can be exposed to air-like gaseous environments at extreme temperatures as high as 700 °C. To protect or reduce the surface degradation of pipes and mechanical components used in in-situ combustion, the use of nickel-based ceramic-metallic (cermet) coating produced by co-electrodeposition of nanosized Al2O3 and TiO2 have been suggested and earlier research on these coatings have shown promising oxidation resistance against atmospheric oxygen and combustion gases at elevated temperatures. Co-electrodeposition of nickel-based cermet coatings is a low-cost method that has the benefit of allowing both internal and external surfaces of pipes and components to be coated during a single electroplating process. Research has shown that the volume fraction of dispersed nanosized Al2O3 and TiO2 particles in the nickel matrix which affects the oxidation resistance of the coating can be controlled by the concentration of these particles in the electrolyte solution, as well as the applied current density during electrodeposition. This paper investigates the high temperature oxidation behaviour of novel nanostructured cermet coatings composed of two types of dispersed nanosized ceramic particles (Al2O3 and TiO2) in a nickel matrix and produced by coelectrodeposition technique as a function of the concentration of these particles in the electrolyte solution and applied current density. For this purpose, high temperature oxidation tests were conducted in dry air for 96 hours at 700 °C to obtain mass changes (per unit of area) at specific time

  8. Microstructure and high temperature oxidation resistance of in-situ synthesized TiN/Ti_3Al intermetallic composite coatings on Ti6Al4V alloy by laser cladding process

    International Nuclear Information System (INIS)

    Liu, Hongxi; Zhang, Xiaowei; Jiang, Yehua; Zhou, Rong

    2016-01-01

    High temperature anti-oxidation TiN/Ti_3Al intermetallic composite coatings were fabricated with the powder and AlN powder on Ti6Al4V titanium alloy surface by 6 kW transverse-flow CO_2 laser apparatus. The chemical composition, morphology and microstructure of the TiN/Ti_3Al composite coatings were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). In order to evaluate the high temperature oxidation resistance of TiN/Ti_3Al coating, the isothermal oxidation test was performed in a high temperature resistance furnace at 600 °C and 800 °C, respectively. The result shows that the composite coating has a rapidly solidified fine microstructure consisting of TiN primary phase (granular-like, flake-like or dendrites), with an even distribution in Ti_3Al matrix. It indicates that a physical and chemical reaction between Ti powder and AlN powder has completely occurred under the laser irradiation condition. In addition, the microhardness of the TiN/Ti3Al intermetallic composite coating is 3.4 times higher than that of the Ti6Al4V alloy substrate and reaches 844 HV_0_._2. The high temperature oxidation behavior test reveals that the high temperature oxidation resistance of TiN/Ti_3Al composite coating is much better than that of titanium alloy substrate. The excellent high temperature oxidation resistance of TiN/Ti_3Al intermetallic composite coating is attributed to the formation of reinforced phases TiN, Al_2O_3 and TiO_2. The laser cladding TiN/Ti_3Al intermetallic composite coating is anticipated to be a promising high temperature oxidation resistance coating for Ti6Al4V alloy. - Highlights: • In-situ TiN/Ti_3Al composite coating was synthesized on Ti6Al4V alloy by laser cladding. • The influence of Ti and AlN molar ratio on the microstructure of the coating was studied. • The TiN/Ti_3Al intermetallic coating is mainly composed of α-Ti, TiN and Ti_3Al phases. • The

  9. Application of a Coated Film Catalyst Layer Model to a High Temperature Polymer Electrolyte Membrane Fuel Cell with Low Catalyst Loading Produced by Reactive Spray Deposition Technology

    Directory of Open Access Journals (Sweden)

    Timothy D. Myles

    2015-10-01

    Full Text Available In this study, a semi-empirical model is presented that correlates to previously obtained experimental overpotential data for a high temperature polymer electrolyte membrane fuel cell (HT-PEMFC. The goal is to reinforce the understanding of the performance of the cell from a modeling perspective. The HT-PEMFC membrane electrode assemblies (MEAs were constructed utilizing an 85 wt. % phosphoric acid doped Advent TPS® membranes for the electrolyte and gas diffusion electrodes (GDEs manufactured by Reactive Spray Deposition Technology (RSDT. MEAs with varying ratios of PTFE binder to carbon support material (I/C ratio were manufactured and their performance at various operating temperatures was recorded. The semi-empirical model derivation was based on the coated film catalyst layer approach and was calibrated to the experimental data by a least squares method. The behavior of important physical parameters as a function of I/C ratio and operating temperature were explored.

  10. Performance of iron–chromium–aluminum alloy surface coatings on Zircaloy 2 under high-temperature steam and normal BWR operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Weicheng; Mouche, Peter A.; Han, Xiaochun [University of Illinois, Department of Nuclear, Radiological, and Plasma Engineering, Urbana, IL 61801 (United States); Heuser, Brent J., E-mail: bheuser@illinois.edu [University of Illinois, Department of Nuclear, Radiological, and Plasma Engineering, Urbana, IL 61801 (United States); Mandapaka, Kiran K.; Was, Gary S. [University of Michigan, Department of Nuclear Engineering and Radiological Sciences, Ann Arbor, MI 48109 (United States)

    2016-03-15

    Iron-chromium-aluminum (FeCrAl) coatings deposited on Zircaloy 2 (Zy2) and yttria-stabilized zirconia (YSZ) by magnetron sputtering have been tested with respect to oxidation weight gain in high-temperature steam. In addition, autoclave testing of FeCrAl-coated Zy2 coupons under pressure-temperature-dissolved oxygen coolant conditions representative of a boiling water reactor (BWR) environment has been performed. Four different FeCrAl compositions have been tested in 700 °C steam; compositions that promote alumina formation inhibited oxidation of the underlying Zy2. Parabolic growth kinetics of alumina on FeCrAl-coated Zy2 is quantified via elemental depth profiling. Autoclave testing under normal BWR operating conditions (288 °C, 9.5 MPa with normal water chemistry) up to 20 days demonstrates observable weight gain over uncoated Zy2 simultaneously exposed to the same environment. However, no FeCrAl film degradation was observed. The 900 °C eutectic in binary Fe–Zr is addressed with the FeCrAl-YSZ system. - Graphical abstract: Weight gain normalized to total sample surface area versus time during 700 °C steam exposure for FeCrAl samples with different composition (A) and Fe/Cr/Al:62/4/34 (B). In both cases, the responses of uncoated Zry2 (Zry2-13A and Zry2-19A) are shown for comparison. This uncoated Zry2 response shows the expected pre-transition quasi-cubic kinetic behavior and eventual breakaway (linear) kinetics. Highlights: • FeCrAl coatings deposited on Zy2 have been tested with respect to oxidation in high-temperature steam. • FeCrAl compositions promoting alumina formation inhibited oxidation of Zy2 and delay weight gain. • Autoclave testing to 20 days of coated Zy2 in a simulated BWR environment demonstrates minimal weight gain and no film degradation. • The 900 °C eutectic in binary Fe-Zr is addressed with the FeCrAl-YSZ system.

  11. Investigation of laser cladding high temperature anti-wear composite coatings on Ti6Al4V alloy with the addition of self-lubricant CaF2

    International Nuclear Information System (INIS)

    Xiang, Zhan-Feng; Liu, Xiu-Bo; Ren, Jia; Luo, Jian; Shi, Shi-Hong; Chen, Yao; Shi, Gao-Lian; Wu, Shao-Hua

    2014-01-01

    Highlights: • A novel high temperature self-lubricating wear-resistant coating was fabricated. • TiC carbides and self-lubricant CaF 2 were “in situ” synthesized in the coating. • The coating with the addition of CaF 2 possessed superior properties than without. - Abstract: To improve the high-temperature tribological properties of Ti–6Al–4V alloy, γ-NiCrAlTi/TiC and γ-NiCrAlTi/TiC/CaF 2 coatings were fabricated on Ti–6Al–4V alloy by laser cladding. The phase compositions and microstructure of the coatings were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). The tribological behaviors were evaluated using a ball-on-disk tribometer from ambient temperature to 600 °C under dry sliding wear conditions and the corresponding wear mechanisms were discussed. The results indicated that the γ-NiCrAlTi/TiC/CaF 2 coating consisted of α-Ti, the “in situ” synthesized TiC block particles and dendrite, γ-NiCrAlTi solid solution and spherical CaF 2 particles. The wear rates of γ-NiCrAlTi/TiC/CaF 2 coating were decreased greatly owing to the combined effects of the reinforced carbides and continuous lubricating films. Furthermore, the friction coefficients of γ-NiCrAlTi/TiC/CaF 2 coating presented minimum value of 0.21 at 600 °C, which was reduced by 43% and 50% compared to the substrate and γ-NiCrAlTi/TiC coating respectively. It was considered that the γ-NiCrAlTi/TiC/CaF 2 coating exhibited excellent friction-reducing and anti-wear properties at high temperature

  12. Investigation of laser cladding high temperature anti-wear composite coatings on Ti6Al4V alloy with the addition of self-lubricant CaF{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Zhan-Feng [School of Mechanical and Electric Engineering, Soochow University, 178 East Ganjiang Road, Suzhou 215006 (China); Liu, Xiu-Bo, E-mail: liuxiubo@suda.edu.cn [School of Mechanical and Electric Engineering, Soochow University, 178 East Ganjiang Road, Suzhou 215006 (China); Ren, Jia; Luo, Jian; Shi, Shi-Hong; Chen, Yao [School of Mechanical and Electric Engineering, Soochow University, 178 East Ganjiang Road, Suzhou 215006 (China); Shi, Gao-Lian; Wu, Shao-Hua [Suzhou Institute of Industrial Technology, Suzhou 215104 (China)

    2014-09-15

    Highlights: • A novel high temperature self-lubricating wear-resistant coating was fabricated. • TiC carbides and self-lubricant CaF{sub 2} were “in situ” synthesized in the coating. • The coating with the addition of CaF{sub 2} possessed superior properties than without. - Abstract: To improve the high-temperature tribological properties of Ti–6Al–4V alloy, γ-NiCrAlTi/TiC and γ-NiCrAlTi/TiC/CaF{sub 2} coatings were fabricated on Ti–6Al–4V alloy by laser cladding. The phase compositions and microstructure of the coatings were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). The tribological behaviors were evaluated using a ball-on-disk tribometer from ambient temperature to 600 °C under dry sliding wear conditions and the corresponding wear mechanisms were discussed. The results indicated that the γ-NiCrAlTi/TiC/CaF{sub 2} coating consisted of α-Ti, the “in situ” synthesized TiC block particles and dendrite, γ-NiCrAlTi solid solution and spherical CaF{sub 2} particles. The wear rates of γ-NiCrAlTi/TiC/CaF{sub 2} coating were decreased greatly owing to the combined effects of the reinforced carbides and continuous lubricating films. Furthermore, the friction coefficients of γ-NiCrAlTi/TiC/CaF{sub 2} coating presented minimum value of 0.21 at 600 °C, which was reduced by 43% and 50% compared to the substrate and γ-NiCrAlTi/TiC coating respectively. It was considered that the γ-NiCrAlTi/TiC/CaF{sub 2} coating exhibited excellent friction-reducing and anti-wear properties at high temperature.

  13. Aluminide protective coatings on high–temperature creep resistant cast steel

    OpenAIRE

    J. Kubicki; A. Kochmańska

    2009-01-01

    This paper presents the results of research on aluminide protective coatings manufactured on high–temperature creep resistant cast steel. The main purpose of these coatings is protection against the high temperature corrosion, especially at high carburizing potential atmosphere. Coatings were obtained on cast steel type G–XNiCrSi36–18 with the following methods: pack cementation, paste method, cast method and slurry cementation. The phase composition, thickness and morphology of coatings were...

  14. Properties of recent IBAD-MOCVD Coated Conductors relevant to their high field, low temperature magnet use

    OpenAIRE

    Braccini, V; Xu, A; Jaroszynski, J; Xin, Y; Larbalestier, D C; Chen, Y; Carota, G; Dackow, J; Kesgin, I; Yao, Y; Guevara, A; Shi, T; Selvamanickam, V

    2010-01-01

    BaZrO3 (BZO) nanorods are now incorporated into production IBAD-MOCVD coated conductors. Here we compare several examples of both BZO-free and BZO-containing coated conductors using critical current (Ic) characterizations at 4.2 K over their full angular range up to fields of 31 T. We find that BZO nanorods do not produce any c-axis distortion of the critical current density Jc(theta) curve at 4.2 K at any field, but also that pinning is nevertheless strongly enhanced compared to the non-BZO ...

  15. HIGH-PERFORMANCE COATING MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. High gain durable anti-reflective coating

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-06-27

    Disclosed herein are polysilsesquioxane-based anti-reflective coating (ARC) compositions, methods of preparation, and methods of deposition on a substrate. In one embodiment, the polysilsesquioxane of this disclosure is prepared in a two-step process of acid catalyzed hydrolysis of organoalkoxysilane followed by addition of tetralkoxysilane that generates silicone polymers with >40 mol % silanol based on Si-NMR. These high silanol siloxane polymers are stable and have a long shelf-life in polar organic solvents at room temperature. Also disclosed are low refractive index ARC made from these compositions with and without additives such as porogens, templates, thermal radical initiator, photo radical initiators, crosslinkers, Si--OH condensation catalyst and nano-fillers. Also disclosed are methods and apparatus for applying coatings to flat substrates including substrate pre-treatment processes, coating processes and coating curing processes including skin-curing using hot-air knives. Also disclosed are coating compositions and formulations for highly tunable, durable, highly abrasion-resistant functionalized anti-reflective coatings.

  17. Papers about coated particles, graphitic and metallic materials for progressive high-temperature reactors at the Reactor Meeting 1978

    International Nuclear Information System (INIS)

    Rottmann, J.

    1978-09-01

    In the contributions, questions on the development, the radiation and the high-temperature behaviour and the characterization of fuel element particles are treated. Furthermore the resistance and radiation behaviour of graphitic materials are discussed. Finally, questions on the choice of high-temperature alloys for nuclear process heat facilities are discussed and the testing-equipment of the Nuclear Research Centre as well as first results of the long-time experiments are presented. The work was performed within the frame of the projects 'HTR-Fuel Element Cycle' and 'Prototype Nuclear Process Heat', which are sponsored by the Federal Ministry of Research and Technology of the Federal Republic of Germany and of the state of North-Rhine-Westfalia. Partner firms, who participate in the two projects are Gelsenberg AG, Gesellschaft fuer Hochtemperaturreaktor-Technik mbH, Hochtemperaturreaktor-Brennelement GmbH, Hochtemperatur-Reaktorbau GmbH, Kernforschungsanlage Juelich GmbH, NUKEM GmbH, SIGRI Elektrographit GmbH/Ringsdorff-Werke GmbH, Bergbauforschung GmbH und Rheinische Braunkohlenwerke AG. (orig./UA) [de

  18. Irradiation test HT-31: high-temperature irradiation behavior of LASL-made extruded fuel rods and LASL-made coated particles

    International Nuclear Information System (INIS)

    Wagner, P.; Reiswig, R.D.; Hollabaugh, C.M.; White, R.W.; Davidson, K.V.; Schell, D.H.

    1977-04-01

    Three LASL-made extruded graphite and coated particle fuel rods have been irradiated in the Oak Ridge National Laboratory High Fluence Isotope Reactor test HT-31. Test conditions were about 9 x 10 21 nvt(E > .18 MeV) at 1250 0 C. The graphite matrix showed little or no effect of the irradiation. LASL-made ZrC containing coated particles with ZrC coats and ZrC-doped pyrolytic carbon coats showed no observable effects of the irradiation

  19. Effect of substrate preheating temperature and coating thickness on residual stress in plasma sprayed hydroxyapatite coating

    International Nuclear Information System (INIS)

    Tang, Dapei

    2015-01-01

    A thermal-mechanical coupling model was developed based on thermal-elastic- plastic theory according the special process of plasma spraying Hydroxyapatite (HA) coating upon Ti-6Al-4V substrate. On the one hand, the classical Fourier transient heat conduction equation was modified by introducing the effect item of deformation on temperature, on the other hand, the Johnson-Cook model, suitable for high temperature and high strain rate conditions, was used as constitutive equation after considering temperature softening effect, strain hardening effect and strain rate reinforcement effect. Based on the above coupling model, the residual stress field within the HA coating was simulated by using finite element method (FEM). Meanwhile, the substrate preheating temperature and coating thickness on the influence of residual stress components were calculated, respectively. The failure modes of coating were also preliminary analyzed. In addition, in order to verify the reliability of calculation, the material removal measurement technique was applied to determine the residual stress of HA coating near the interface. Some important conclusions are obtained. (paper)

  20. Microstructure and high-temperature oxidation resistance of TiN/Ti3Al intermetallic matrix composite coatings on Ti6Al4V alloy surface by laser cladding

    Science.gov (United States)

    Zhang, Xiaowei; Liu, Hongxi; Wang, Chuanqi; Zeng, Weihua; Jiang, Yehua

    2010-11-01

    A high-temperature oxidation resistant TiN embedded in Ti3Al intermetallic matrix composite coating was fabricated on titanium alloy Ti6Al4V surface by 6kW transverse-flow CO2 laser apparatus. The composition, morphology and microstructure of the laser clad TiN/Ti3Al intermetallic matrix composite coating were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). In order to evaluate the high-temperature oxidation resistance of the composite coatings and the titanium alloy substrate, isothermal oxidation test was performed in a conventional high-temperature resistance furnace at 600°C and 800°C respectively. The result shows that the laser clad intermetallic composite coating has a rapidly solidified fine microstructure consisting of TiN primary phase (granular-like, flake-like, and dendrites), and uniformly distributed in the Ti3Al matrix. It indicates that a physical and chemical reaction between the Ti powder and AlN powder occurred completely under the laser irradiation. In addition, the microhardness of the TiN/Ti3Al intermetallic matrix composite coating is 844HV0.2, 3.4 times higher than that of the titanium alloy substrate. The high-temperature oxidation resistance test reveals that TiN/Ti3Al intermetallic matrix composite coating results in the better modification of high-temperature oxidation behavior than the titanium substrate. The excellent high-temperature oxidation resistance of the laser cladding layer is attributed to the formation of the reinforced phase TiN and Al2O3, TiO2 hybrid oxide. Therefore, the laser cladding TiN/Ti3Al intermetallic matrix composite coating is anticipated to be a promising oxidation resistance surface modification technique for Ti6Al4V alloy.

  1. Corrosion testing of NiCrAl(Y) coating alloys in high-temperature and supercritical water

    International Nuclear Information System (INIS)

    Biljan, S.; Huang, X.; Qian, Y.; Guzonas, D.

    2011-01-01

    With the development of Generation IV (Gen IV) nuclear power reactors, materials capable of operating in high-temperature and supercritical water environment are essential. This study focuses on the corrosion behavior of five alloys with compositions of Ni20Cr, Ni5Al, Ni50Cr, Ni20Cr5Al and Ni20Cr10AlY above and below the critical point of water. Corrosion tests were conducted at three different pressures, while the temperature was maintained at 460 o C, in order to examine the effects of water density on the corrosion. From the preliminary test results, it was found that the binary alloys Ni20Cr and Ni50Cr showed weight loss above the critical point (23.7 MPa and 460 o C). The higher Cr content alloy Ni50Cr suffered more weight loss than Ni-20Cr under the same conditions. Accelerated weight gain was observed above the critical point for the binary alloy Ni5Al. The combination of Cr, Al and Y in Ni20Cr10AlY provides stable scale formation under all testing conditions employed in this study. (author)

  2. Effects of high temperature treatment on microstructure and mechanical properties of laser-clad NiCrBSi/WC coatings on titanium alloy substrate

    International Nuclear Information System (INIS)

    Li, Guang Jie; Li, Jun; Luo, Xing

    2014-01-01

    Laser-clad composite coatings on the Ti6Al4V substrate were heat-treated at 700, 800, and 900 °C for 1 h. The effects of post-heat treatment on the microstructure, microhardness, and fracture toughness of the coatings were investigated by scanning electron microscopy, X-ray diffractometry, energy dispersive spectroscopy, and optical microscopy. The wear resistance of the coatings was evaluated under dry reciprocating sliding friction at room temperature. The coatings mainly comprised some coarse gray blocky (W,Ti)C particles accompanied by the fine white WC particles, a large number of black TiC cellular/dendrites, and the matrix composed of NiTi and Ni 3 Ti; some unknown rich Ni- and Ti-rich particles with sizes ranging from 10 nm to 50 nm were precipitated and uniformly distributed in the Ni 3 Ti phase to form a thin granular layer after heat treatment at 700 °C. The granular layer spread from the edge toward the center of the Ni 3 Ti phase with increasing temperature. A large number of fine equiaxed Cr 23 C 6 particles with 0.2–0.5 μm sizes were observed around the edges of the NiTi supersaturated solid solution when the temperature was further increased to 900 °C. The microhardness and fracture toughness of the coatings were improved with increased temperature due to the dispersion-strengthening effect of the precipitates. Dominant wear mechanisms for all the coatings included abrasive and delamination wear. The post-heat treatment not only reduced wear volume and friction coefficient, but also decreased cracking susceptibility during sliding friction. Comparatively speaking, the heat-treated coating at 900 °C presented the most excellent wear resistance. - Highlights: • TiC + WC reinforced intermetallic compound matrix composite coatings were produced. • The formation mechanism of the reinforcements was analyzed. • Two precipitates were generated at elevated temperature. • Cracking susceptibility and microhardness of the coatings were improved

  3. Seasonal variation in coat characteristics, tick loads, cortisol levels, some physiological parameters and temperature humidity index on Nguni cows raised in low- and high-input farms

    Science.gov (United States)

    Katiyatiya, C. L. F.; Muchenje, V.; Mushunje, A.

    2015-06-01

    Seasonal variations in hair length, tick loads, cortisol levels, haematological parameters (HP) and temperature humidity index (THI) in Nguni cows of different colours raised in two low-input farms, and a commercial stud was determined. The sites were chosen based on their production systems, climatic characteristics and geographical locations. Zazulwana and Komga are low-input, humid-coastal areas, while Honeydale is a high-input, dry-inland Nguni stud farm. A total of 103 cows, grouped according to parity, location and coat colour, were used in the study. The effects of location, coat colour, hair length and season were used to determine tick loads on different body parts, cortisol levels and HP in blood from Nguni cows. Highest tick loads were recorded under the tail and the lowest on the head of each of the animals ( P cows recorded the highest tick loads under the tails of all the cows used in the study from the three farms ( P cows with long hairs. Hair lengths were longest during the winter season in the coastal areas of Zazulwana and Honeydale ( P cows had significantly longer ( P heat stress in Nguni cows.

  4. Aluminide protective coatings on high–temperature creep resistant cast steel

    Directory of Open Access Journals (Sweden)

    J. Kubicki

    2009-10-01

    Full Text Available This paper presents the results of research on aluminide protective coatings manufactured on high–temperature creep resistant cast steel. The main purpose of these coatings is protection against the high temperature corrosion, especially at high carburizing potential atmosphere. Coatings were obtained on cast steel type G–XNiCrSi36–18 with the following methods: pack cementation, paste method, cast method and slurry cementation. The phase composition, thickness and morphology of coatings were determined. Coatings capacity of carbon diffusion inhibition and thermal shocks resistance of coatings were determined with different methods. It was found, that all of the coatings reduce carbon diffusion in different degree and all coatings liable to degradation in consequence cracking and oxidation. Coating life time is mainly dependent on morphology, phase composition and service condition (thermal shocks first of all.

  5. Influence of high temperature annealing on the structure, hardness and tribological properties of diamond-like carbon and TiAlSiCN nanocomposite coatings

    International Nuclear Information System (INIS)

    Xie, Z.W.; Wang, L.P.; Wang, X.F.; Huang, L.; Lu, Y.; Yan, J.C.

    2011-01-01

    Diamond-like carbon (DLC) and TiAlSiCN nanocomposite coatings were synthesized and annealed at different temperatures in a vacuum environment. The microstructure, hardness and tribological properties of as-deposited and annealed DLC-TiAlSiCN nanocomposite coatings were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, nano-indentation and friction tests. The TEM results reveal that the as-deposited DLC-TiAlSiCN coating has a unique nanocomposite structure consisting of TiCN nanocrystals embedded in an amorphous matrix consisting of a-Si 3 N 4 , a-SiC, a-CN and DLC, and the structure changed little after annealing at 800 °C. However, XPS and Raman results show that an obvious graphitization of the DLC phase occurred during the annealing process and it worsened with annealing temperature. Because of the graphitization, the hardness of the DLC-TiAlSiCN coating after annealing at 800 °C decreased from 45 to 36 GPa. In addition, the DLC-TiAlSiCN coating after annealing at 800 °C has a similar friction coefficient to the as-deposited coating.

  6. Irradiation test OF-2: high-temperature irradiation behavior of LASL-made fuel rods and LASL-made coated particles

    International Nuclear Information System (INIS)

    Wagner, P.; Reiswig, R.D.; Hollabaugh, C.M.; White, R.W.; O'Rourke, J.A.; Davidson, K.V.; Schell, D.H.

    1977-10-01

    Three LASL-made, substoichiometric ZrC-coated particles with inert kernels, and two high-density molded graphite fuel rods that contained LASL-made, ZrC-coated fissile particles were irradiated in the Oak Ridge Research Reactor test OF-2. The severest test conditions were 8.36 x 10 21 nvt (E greater than 0.18 MeV) at 1350 0 C. The graphite matrix showed no effect of the irradiation. There was no interaction between the matrix and any of the particle coats. The loose ZrC coated particles with inert kernels showed no irradiation effects. The graded ZrC-C coats on the fissile particles were cracked. It is postulated that the cracking is associated with the low LTI deposition rate and is not related to the ZrC

  7. Temperature of loose coated particles in irradiation tests

    International Nuclear Information System (INIS)

    Conlin, J.A.

    1975-04-01

    An analysis is presented of the temperature of a monolayer bed of loose High-Temperature Gas-Cooled Reactor (HTGR) type fissioning fuel particles in an annular cavity. Both conduction and radiant heat transfer are taken into account, and the effect of particle contact with the annular cavity surfaces is evaluated. Charts are included for the determination of the maximum surface temperature of the particle coating for any size particle or power generation rate in a fuel bed of this type. The charts are intended for the design and evaluation of irradiation experiments on loose beds of coated fuel particles of the type used in HTGRs. Included in an Appendix is a method for estimating the temperature of a particle in circular hole. (U.S.)

  8. Mathematical modeling of photoinitiated coating degradation: Effects of coating glass transition temperature and light stabilizers

    DEFF Research Database (Denmark)

    Kiil, Søren; G.de With, R.A.T.M.Van Benthem

    2013-01-01

    A mathematical model, describing coating degradation mechanisms of thermoset coatings exposed to ultraviolet radiation and humidity at constant temperature, was extended to simulate the behavior of a coating with a low glass transition temperature. The effects of adding light stabilizers (a UV...

  9. Microstructure and high temperature oxidation resistance of in-situ synthesized TiN/Ti{sub 3}Al intermetallic composite coatings on Ti6Al4V alloy by laser cladding process

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongxi, E-mail: piiiliuhx@sina.com; Zhang, Xiaowei; Jiang, Yehua; Zhou, Rong

    2016-06-15

    High temperature anti-oxidation TiN/Ti{sub 3}Al intermetallic composite coatings were fabricated with the powder and AlN powder on Ti6Al4V titanium alloy surface by 6 kW transverse-flow CO{sub 2} laser apparatus. The chemical composition, morphology and microstructure of the TiN/Ti{sub 3}Al composite coatings were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). In order to evaluate the high temperature oxidation resistance of TiN/Ti{sub 3}Al coating, the isothermal oxidation test was performed in a high temperature resistance furnace at 600 °C and 800 °C, respectively. The result shows that the composite coating has a rapidly solidified fine microstructure consisting of TiN primary phase (granular-like, flake-like or dendrites), with an even distribution in Ti{sub 3}Al matrix. It indicates that a physical and chemical reaction between Ti powder and AlN powder has completely occurred under the laser irradiation condition. In addition, the microhardness of the TiN/Ti3Al intermetallic composite coating is 3.4 times higher than that of the Ti6Al4V alloy substrate and reaches 844 HV{sub 0.2}. The high temperature oxidation behavior test reveals that the high temperature oxidation resistance of TiN/Ti{sub 3}Al composite coating is much better than that of titanium alloy substrate. The excellent high temperature oxidation resistance of TiN/Ti{sub 3}Al intermetallic composite coating is attributed to the formation of reinforced phases TiN, Al{sub 2}O{sub 3} and TiO{sub 2}. The laser cladding TiN/Ti{sub 3}Al intermetallic composite coating is anticipated to be a promising high temperature oxidation resistance coating for Ti6Al4V alloy. - Highlights: • In-situ TiN/Ti{sub 3}Al composite coating was synthesized on Ti6Al4V alloy by laser cladding. • The influence of Ti and AlN molar ratio on the microstructure of the coating was studied. • The TiN/Ti{sub 3}Al intermetallic

  10. High-performance supercapacitors of carboxylate-modified hollow carbon nanospheres coated on flexible carbon fibre paper: Effects of oxygen-containing group contents, electrolytes and operating temperature

    International Nuclear Information System (INIS)

    Phattharasupakun, Nutthaphon; Wutthiprom, Juthaporn; Suktha, Phansiri; Iamprasertkun, Pawin; Chanlek, Narong; Shepherd, Celine; Hadzifejzovic, Emina; Moloney, Mark G.; Foord, John S.; Sawangphruk, Montree

    2017-01-01

    Although functionalized carbon-based materials have been widely used as the supercapacitor electrodes, the optimum contents of the functional groups, the charge storage mechanisms, and the effects of electrolytes and operating temperature have not yet been clearly investigated. In this work, carboxylate-modified hollow carbon nanospheres (c-HCN) with different functional group contents synthesized by an oxidation process of carbon nanospheres with nitric acid were coated on flexible carbon fibre paper and used as the supercapacitor electrodes. An as-fabricated supercapacitor of the c-HCN with a finely tuned 6.2 atomic % of oxygen of the oxygen-containing groups in an ionic liquid electrolyte exhibits a specific capacitance of 390 F g"−"1, a specific energy of 115 Wh kg"−"1, and a maximum specific power of 13548 W kg"−"1 at 70 °C. The charge storage mechanism investigated is based on the chemical adsorption of the ionic liquid electrolyte on the c-HCN electrode. This process is highly reversible leading to high capacity retention. The supercapacitor in this work may be practically used in many high energy and power applications.

  11. High Critical Current Coated Conductors

    Energy Technology Data Exchange (ETDEWEB)

    Paranthaman, M. P.; Selvamanickam, V. (SuperPower, Inc.)

    2011-12-27

    One of the important critical needs that came out of the DOE’s coated conductor workshop was to develop a high throughput and economic deposition process for YBCO. Metal-organic chemical vapor deposition (MOCVD) technique, the most critical steps in high technical micro fabrications, has been widely employed in semiconductor industry for various thin film growth. SuperPower has demonstrated that (Y,Gd)BCO films can be deposited rapid with world record performance. In addition to high critical current density with increased film thickness, flux pinning properties of REBCO films needs to be improved to meet the DOE requirements for various electric-power equipments. We have shown that doping with Zr can result in BZO nanocolumns, but at substantially reduced deposition rate. The primary purpose of this subtask is to develop high current density MOCVD-REBCO coated conductors based on the ion-beam assisted (IBAD)-MgO deposition process. Another purpose of this subtask is to investigate HTS conductor design optimization (maximize Je) with emphasis on stability and protection issues, and ac loss for REBCO coated conductors.

  12. Preliminary evaluation of PS300: A new self-lubricating high temperature composite coating for use to 800{degrees}C

    Energy Technology Data Exchange (ETDEWEB)

    DellaCorte, C.; Edmonds, B.J.

    1996-12-31

    This paper introduces PS300, a plasma sprayed, self-lubricating composite coating for use in sliding contacts at temperatures to 800{degrees}C. PS300 is a metal bonded chrome oxide coating with silver and BaF{sub 2}/CaF{sub 2} eutectic solid lubricant additives. PS300 is similar to PS200, a chromium carbide based coating; which is currently being investigated for a variety of tribological applications. In pin-on-disk testing up to 650{degrees}C, PS300 exhibited comparable friction and wear properties to PS200. The PS300 matrix, which is predominantly chromium oxide rather than chromium carbide, does not require diamond grinding and polishes readily with silicon carbide abrasives greatly reducing manufacturing costs compared to PS200. It is anticipated that PS300 has potential for sliding bearing and seal applications in both aerospace and general industry.

  13. The behavior of ZrO{sub 2}/20%Y{sub 2}O{sub 3} and Al{sub 2}O{sub 3} coatings deposited on aluminum alloys at high temperature regime

    Energy Technology Data Exchange (ETDEWEB)

    Pintilei, G.L., E-mail: laura_rares082008@yahoo.com [Pitesti University, Faculty of Mechanics and Technology, Str. Targu din Vale nr.1, 110040 Pitesti, Arges (Romania); Technical University “Gheorghe Asachi” of Iasi, Faculty of Mechanics, Bld D. Mangeron nr. 61, 700050 Iasi (Romania); Crismaru, V.I. [Technical University “Gheorghe Asachi” of Iasi, Faculty of Mechanics, Bld D. Mangeron nr. 61, 700050 Iasi (Romania); Abrudeanu, M. [Pitesti University, Faculty of Mechanics and Technology, Str. Targu din Vale nr.1, 110040 Pitesti, Arges (Romania); Munteanu, C. [Technical University “Gheorghe Asachi” of Iasi, Faculty of Mechanics, Bld D. Mangeron nr. 61, 700050 Iasi (Romania); Baciu, E.R. [University of Medicine and Pharmacy “Gr.T.Popa”, Department Implantology, Removable Restorations, Technology, Str. Universitatii nr. 16, 700115 Iasi (Romania); Istrate, B.; Basescu, N. [Technical University “Gheorghe Asachi” of Iasi, Faculty of Mechanics, Bld D. Mangeron nr. 61, 700050 Iasi (Romania)

    2015-10-15

    Highlights: • In both the ZrO{sub 2}/20%Y{sub 2}O{sub 3} and Al{sub 2}O{sub 3} coatings the high temperature caused a decrease of pores volume and a lower thickness of the interface between successive splats. • The NiCr bond layer in the sample with a ZrO{sub 2}/20%Y{sub 2}O{sub 3} suffered a fragmentation due to high temperature exposure and thermal expansion which can lead to coating exfoliation. • The NiCr bond layer in the sample with an Al{sub 2}O{sub 3} coating showed an increase of pore volume due to high temperature. - Abstract: Aluminum alloy present numerous advantages like lightness, high specific strength and diversity which recommend them to a high number of applications from different fields. In extreme environments the protection of aluminum alloys is difficult and requires a high number of requirements like high temperature resistance, thermal fatigue resistance, corrosion fatigue resistance and galvanic corrosion resistance. To obtain these characteristics coatings can be applied to the surfaces so they can enhance the mechanical and chemical properties of the parts. In this paper two coatings were considered for deposition on an AA2024 aluminum alloy, ZrO{sub 2}/20%Y{sub 2}O{sub 3} and Al{sub 2}O{sub 3}. To obtain a better adherence of the coating to the base material an additional bond layer of NiCr is used. Both the coatings and bond layer were deposited by atmospheric plasma spraying on the samples. The samples were subjected to a temperature of 500 °C and after that slowly cooled to room temperature. The samples were analyzed by electron microscopy and X-ray diffraction to determine the morphological and phase changes that occurred during the temperature exposure. To determine the stress level in the parts due to thermal expansion a finite element analysis was performed in the same conditions as the tests.

  14. Design and Characterization of High-strength Bond Coats for Improved Thermal Barrier Coating Durability

    Science.gov (United States)

    Jorgensen, David John

    High pressure turbine blades in gas turbine engines rely on thermal barrier coating (TBC) systems for protection from the harsh combustion environment. These coating systems consist of a ceramic topcoat for thermal protection, a thermally grown oxide (TGO) for oxidation passivation, and an intermetallic bond coat to provide compatibility between the substrate and ceramic over-layers while supplying aluminum to sustain Al2O 3 scale growth. As turbine engines are pushed to higher operating temperatures in pursuit of better thermal efficiency, the strength of industry-standard bond coats limits the lifetime of these coating systems. Bond coat creep deformation during thermal cycling leads to a failure mechanism termed rumpling. The interlayer thermal expansion differences, combined with TGO-imposed growth stresses, lead to the development of periodic undulations in the bond coat. The ceramic topcoat has low out-of-plane compliance and thus detaches and spalls from the substrate, resulting in a loss of thermal protection and subsequent degradation of mechanical properties. New creep resistant Ni3Al bond coats were designed with improved high-temperature strength to inhibit this type of premature failure at elevated temperatures. These coatings resist rumpling deformation while maintaining compatibility with the other layers in the system. Characterization methods are developed to quantify rumpling and assess the TGO-bond coat interface toughness of experimental systems. Cyclic oxidation experiments at 1163 °C show that the Ni3Al bond coats do not experience rumpling but have faster oxide growth rates and are quicker to spall TGO than the (Pt,Ni)Al benchmark. However, the Ni 3Al coatings outperformed the benchmark by over threefold in TBC system life due to a higher resistance to rumpling (mechanical degradation) while maintaining adequate oxidation passivation. The Ni3Al coatings eventually grow spinel NiAl2O4 on top of the protective Al2O3 layer, which leads to the

  15. Characterization of oxidation protection coatings for high temperature applications by means of nanoindentation and scanning electron microscopy methods; Charakterisierung von Oxidationsschutzschichten fuer Hochtemperaturanwendungen mittels Nanoindentierung und rasterelektronenmikroskopischen Methoden

    Energy Technology Data Exchange (ETDEWEB)

    Webler, R.; Neumeier, S.; Goeken, M. [Erlangen-Nuernberg Univ., Erlangen (Germany). Lehrstuhl fuer Allgemeine Werkstoffeigenschaften

    2014-10-01

    Oxidation protection coatings are required for thermally highly stressed components such as turbine blades in aircraft engines. Cyclic oxidation experiments were performed on a NiCoCrAlY protective coating of a nickel-based superalloy and hardness and modulus of elasticity (mechanical properties) were determined by nanoindentation before and after the experiments. Microstructure and chemical composition were characterized by means of scanning electron microscopy. Here, the focus is on the phase identification by combining electron backscatter diffraction and energy dispersive X-ray spectroscopy. Findings indicate that the chemical composition strongly influences the mechanical properties.

  16. Method for producing evaporation inhibiting coating for protection of silicon--germanium and silicon--molybdenum alloys at high temperatures in vacuum

    Science.gov (United States)

    Chao, P.J.

    1974-01-01

    A method is given for protecting Si--Ge and Si-- Mo alloys for use in thermocouples. The alloys are coated with silicon to inhibit the evaporation of the alloys at high tempenatures in a vacuum. Specific means and methods are provided. (5 fig) (Official Gazette)

  17. High temperature oxidation resistant cermet compositions

    Science.gov (United States)

    Phillips, W. M. (Inventor)

    1976-01-01

    Cermet compositions are designed to provide high temperature resistant refractory coatings on stainless steel or molybdenum substrates. A ceramic mixture of chromium oxide and aluminum oxide form a coating of chromium oxide as an oxidation barrier around the metal particles, to provide oxidation resistance for the metal particles.

  18. High emissivity TiC coatings for a first wall

    International Nuclear Information System (INIS)

    Groot, P.

    1991-08-01

    Part of the First Wall of the conceptual design of Next European Torus NET consist of radiation cooled carbon tiles. Tile temperature is determined by the optical properties of facing surfaces. Heat transfer to the 316 stainless steel structure can be improved by applying a high emissivity coating. For this purpose ceramic coatings can be applied. This paper deals with development and characterization of atmospheric and vacuum plasma sprayed titanium carbide as high emissivity coatings. Microstructural evaluation of these coatings includes X-ray diffraction and light microscopy of cross-sections. Total emissivities of vacuum and atmospheric plasma sprayed TiC coatings were measured at 525 K at PTB Braunschweig. Reflection measurements were performed at ECN Petten by using a YAG laser with wavelength 1.06 μm at room temperature. The effects of compositional differences on optical properties are discussed. (author). 9 refs.; 5 figs.; 1 tab

  19. Tribological characteristics of electroless Ni–P–MoS2 composite coatings at elevated temperatures

    International Nuclear Information System (INIS)

    Li Zhen; Wang Jingbo; Lu Jinjun; Meng Junhu

    2013-01-01

    Highlights: ► Uniform Ni–P–MoS 2 composite coatings are deposited by electroless plating. ► Friction coefficient of composite coating decreases with the increase of temperature. ► Formation of lubricious oxide film leads to excellent tribological property. - Abstract: Ni–P–MoS 2 composite coatings were deposited on AISI-1045 steel plate by electroless plating followed by a heat treatment at 300 °C for 2 h. The high-temperature tribological characteristics of the composite coatings were evaluated under dry sliding conditions in a tribometer with ball-on-disk configuration. The effect of the co-deposition of MoS 2 on the friction and wear behaviors of composite coatings at elevated temperature was investigated. Scanning electron microscopy was used to determine the morphology of the worn surface of composite coating. The chemical states of some typical elements on the worn surfaces were determined by X-ray photoelectron spectroscope. The results indicate that friction coefficient of the composite coatings decreases with the increase of test temperature up to 500 °C, and the best tribological properties of Ni–P–MoS 2 composite coatings are achieved at 400 °C. The worn surface of Ni–P–MoS 2 composite coatings are characterized by mild scuffing and deformation. The improvement of tribological properties of the composite coatings was attributed to the formation of the lubricious oxide film composed of oxides of Ni and Mo at high temperatures. With the test temperature increasing to 600 °C, the tribological properties of the composite coating begin to deteriorate due to softening of the coating.

  20. Encapsulation of high temperature molten salts

    Science.gov (United States)

    Oxley, James D.; Mathur, Anoop Kumar

    2017-05-16

    The present disclosure relates to a method of encapsulating microcapsules containing relatively high temperature phase change materials and the microcapsules so produced. The microcapsules are coated with an inorganic binder, film former and an inorganic filler. The microcapsules may include a sacrificial layer that is disposed between the particle and the coating. The microcapsules may also include an inner coating layer, sacrificial layer and outer coating layer. The microcapsules are particularly useful for thermal energy storage in connection with, e.g., heat collected from concentrating solar collectors.

  1. Temperature Dependence of Mechanical Properties of TRISO SiC Coatings

    International Nuclear Information System (INIS)

    Kim, Do Kyung; Park, Kwi Il; Lee, Hyeon Keun; Seong, Young Hoon; Lee, Seung Jun

    2009-04-01

    SiC coating layer has been introduced as protective layer in TRISO nuclear fuel particle of high temperature gas cooled reactor (HTGR) due to excellent mechanical stability at high temperature. It is important to study for high temperature stability in SiC coating layers, because TRISO fuel particles were operating at high temperature around 1000 .deg. C. In this study, the nanoindentation test and micro tensile test were conducted in order to measure the mechanical properties of SiC coating layers at elevated temperature. SiC coating film was fabricated on the carbon substrate using chemical vapor deposition process with different microstructures and thicknesses. Nanoindentation test was performed for the analysis of the hardness, modulus and creep properties up to 500 .deg. C. Impression creep method applied to nanoindentation and creep properties of SiC coating layers were characterized by nanoindentation creep test. The fracture strength of SiC coating layers was measured by the micro tensile method at room temperature and 500 .deg. C. From the results, we can conclude that the hardness and fracture strength are decreased with temperature and no significant change in the modulus is observed with increase in temperature. The deformation mechanism for indentation creep and creep rate changes as the testing temperature increased

  2. High speed PVD thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Beele, W. [Sulzer Metco Coatings BV (Netherlands); Eschendorff, G. [Sulzer Metco Coatings BV (Netherlands); Eldim BV (Netherlands)

    2006-07-15

    The high speed PVD process (HS-PVD) combines gas phase coating synthesis with high deposition rates. The process has been demonstrated for high purity YSZ deposited as a chemically bonded top thermal barrier with columnar structure of EB-PVD features. The process can manufacture EB-PVD like coatings that match in regards to their TGO-formation and columnar structure. Coatings with a columnar structure formed by individual columns of 1/4 of the diameter of a classical EB-PVD type TBC have been deposited. These coatings have the potential to prove a significant reduction in thermal conductivity and in erosion performance. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  3. High speed PVD thermal barrier coatings

    International Nuclear Information System (INIS)

    Beele, W.; Eschendorff, G.

    2006-01-01

    The high speed PVD process (HS-PVD) combines gas phase coating synthesis with high deposition rates. The process has been demonstrated for high purity YSZ deposited as a chemically bonded top thermal barrier with columnar structure of EB-PVD features. The process can manufacture EB-PVD like coatings that match in regards to their TGO-formation and columnar structure. Coatings with a columnar structure formed by individual columns of 1/4 of the diameter of a classical EB-PVD type TBC have been deposited. These coatings have the potential to prove a significant reduction in thermal conductivity and in erosion performance. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  4. Corrosion resistant coatings suitable for elevated temperature application

    Science.gov (United States)

    Chan, Kwai S [San Antonio, TX; Cheruvu, Narayana Sastry [San Antonio, TX; Liang, Wuwei [Austin, TX

    2012-07-31

    The present invention relates to corrosion resistance coatings suitable for elevated temperature applications, which employ compositions of iron (Fe), chromium (Cr), nickel (Ni) and/or aluminum (Al). The compositions may be configured to regulate the diffusion of metals between a coating and a substrate, which may then influence coating performance, via the formation of an inter-diffusion barrier layer. The inter-diffusion barrier layer may comprise a face-centered cubic phase.

  5. Supersymmetry at high temperatures

    International Nuclear Information System (INIS)

    Das, A.; Kaku, M.

    1978-01-01

    We investigate the properties of Green's functions in a spontaneously broken supersymmetric model at high temperatures. We show that, even at high temperatures, we do not get restoration of supersymmetry, at least in the one-loop approximation

  6. Nickel/Diamond Composite Coating Prepared by High Speed Electrodeposition

    Directory of Open Access Journals (Sweden)

    ZHANG Yan

    2016-10-01

    Full Text Available Nickel/diamond composite coatings were prepared on the basis of a new high speed electroplating bath. The influence of additives, plating parameters and diamond concentration on internal stress was investigated in order to find the solution to decrease the stress introduced by high current density; the micro morphology of the coatings were observed by SEM. The bath and depositing parameters were optimized that thick nickel/diamond composite coatings with low internal stress can be high speed electroplated with a high cathode current density of 30A/dm2. The results show that when plated with bath composition and parameters as follows: sodium dodecyl sulfate 0.5g/L, ammonium acetate 3g/L, sodium citrate 1.5g/L, diamond particles 30g/L; pH value 3-4, temperature 50℃, the composite coatings prepared in high speed have the lowest internal stress.

  7. Effect of a ZrO{sub 2} coating deposited by the sol–gel method on the resistance of FeCrAl alloy in high-temperature oxidation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Chęcmanowski, Jacek Grzegorz, E-mail: jacek.checmanowski@pwr.wroc.pl [Wrocław University of Technology, Faculty of Chemistry, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław (Poland); Szczygieł, Bogdan, E-mail: bogdan.szczygiel@pwr.wroc.pl [Wrocław University of Technology, Faculty of Chemistry, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław (Poland)

    2013-05-15

    One-, three- and five-layer protective ZrO{sub 2} coatings were deposited on a FeCrAl alloy base by the sol–gel method. A zirconium(IV) isopropoxide isopropanol complex was used as the zirconium precursor. It has been shown that zirconium in the amount of 0.3–0.5 wt.% improves the resistance of FeCrAl alloy in high-temperature oxidation conditions (in air at T = 1060 °C for t = 2400 h). Even a very low Zr content affects the morphology, porosity and composition of the forming scale (SEM, EDS). An analysis of the chemical composition of the material after oxidation indicated to-core Zr diffusion. The presence of zirconium prevents catastrophic corrosion of the FeCrAl alloy during oxidation. In the case of the alloy without the reactive element (Zr) this type of corrosion occurred after about 1800 h. The oxidation of the FeCrAl alloy covered with ZrO{sub 2} coatings proceeds in three stages. In the first stage, lasting about 50 h, the mass of the sample grows rapidly, then for 700 h the mass changes minimally and in the third stage the oxidation proceeds according to a parabolic dependence. The presence of Zr on the surface of the FeCrAl alloy significantly contributes to the protective effect of the coatings. - Highlights: ► Multilayer ZrO{sub 2} coatings were deposited on FeCrAl alloy by sol–gel method. ► Study of alloy composition indicates to-core Zr diffusion in high temperature. ► Even very low content affects morphology and porosity of forming scale. ► Zirconium improves the resistance of FeCrAl alloy in high temperature conditions. ► Presence of ZrO{sub 2} prevents catastrophic corrosion of FeCrAl alloy during oxidation.

  8. High Temperature Superconductor Accelerator Magnets

    CERN Document Server

    AUTHOR|(CDS)2079328; de Rijk, Gijs; Dhalle, Marc

    2016-11-10

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding $20T$. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and development before they can be applied in a practical accelerator magnet. In order to study HTS in detail, a five tesla demonstrator magnet named Feather-M2 is designed and constructed. The magnet is based on ReBCO coated conductor, which is assembled into a $10kA$ class Roebel cable. A new and optimized Aligned Block layout is used, which takes advantage of the anisotropy of the conductor. This is achieved by providing local alignment of the Roebel cable in the coil windings with the magnetic field lines. A new Network Model capable of analyzing transient electro-magnetic and thermal phenomena in coated conductor cables and coils is developed. This model is necessary to solve critical issues in coated conductor ac...

  9. High temperature refrigerator

    International Nuclear Information System (INIS)

    Steyert, W.A. Jr.

    1978-01-01

    A high temperature magnetic refrigerator is described which uses a Stirling-like cycle in which rotating magnetic working material is heated in zero field and adiabatically magnetized, cooled in high field, then adiabatically demagnetized. During this cycle the working material is in heat exchange with a pumped fluid which absorbs heat from a low temperature heat source and deposits heat in a high temperature reservoir. The magnetic refrigeration cycle operates at an efficiency 70% of Carnot

  10. High-temperature superconductivity

    International Nuclear Information System (INIS)

    Lynn, J.W.

    1990-01-01

    This book discusses development in oxide materials with high superconducting transition temperature. Systems with Tc well above liquid nitrogen temperature are already a reality and higher Tc's are anticipated. The author discusses how the idea of a room-temperature superconductor appears to be a distinctly possible outcome of materials research

  11. Room temperature synthesis of water-repellent polystyrene nanocomposite coating

    International Nuclear Information System (INIS)

    Guo Yonggang; Jiang Dong; Zhang Xia; Zhang Zhijun; Wang Qihua

    2010-01-01

    A stable superhydrophobic polystyrene nanocomposite coating was fabricated by means of a very simple and easy method. The coating was characterized by scanning electron microscopy and X-ray photoelectron spectrum. The wettability of the products was also investigated. By adding the surface-modified SiO 2 nanoparticles, the wettability of the coating changed to water-repellent superhydrophobic, not only for pure water, but also for a wide pH range of corrosive liquids. The influence of the drying temperature and SiO 2 content on the wettability of the nanocomposite coating was also investigated. It was found that both factors had little or no significant effect on the wetting behavior of the coating surface.

  12. Oxidation of iridium coating on rhenium coated graphite at elevated temperature in stagnated air

    International Nuclear Information System (INIS)

    Huang, Yongle; Bai, Shuxin; Zhang, Hong; Ye, Yicong

    2015-01-01

    Highlights: • Continuous and dense Ir coatings were prepared on graphite by electrodepostion. • The purification of the as-prepared Ir coating was higher than about 99.98%. • The Ir/Re/C specimen kept integrity without significant failures after oxidation. • The average oxidation rate of the Ir coating was about 0.219 mg/(cm 2 min). • Penetrating holes at gains boundaries resulted in the failure of the Ir coating. - Abstract: Continuous and dense iridium coatings were prepared on the rhenium coated graphite specimens by electrodeposition. The iridium/rhenium coated graphite (Ir/Re/C) specimens were oxidized at elevated temperatures in stagnated air for 3600 s. The purification of the as-prepared Ir coating was higher than about 99.98% with the main impurity elements Si, Al, Fe and Ru. After oxidation, the Ir/Re/C specimens kept integrity without significant failures and the average oxidation rate was about 0.219 mg/(cm 2 min). Pores were found at the grain boundaries and concentrated to penetrating holes with the growth of Ir grains, which resulted in disastrous failures of the Ir coating

  13. Oxidation of iridium coating on rhenium coated graphite at elevated temperature in stagnated air

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yongle; Bai, Shuxin, E-mail: NUDT_MSE_501@163.com; Zhang, Hong; Ye, Yicong

    2015-02-15

    Highlights: • Continuous and dense Ir coatings were prepared on graphite by electrodepostion. • The purification of the as-prepared Ir coating was higher than about 99.98%. • The Ir/Re/C specimen kept integrity without significant failures after oxidation. • The average oxidation rate of the Ir coating was about 0.219 mg/(cm{sup 2} min). • Penetrating holes at gains boundaries resulted in the failure of the Ir coating. - Abstract: Continuous and dense iridium coatings were prepared on the rhenium coated graphite specimens by electrodeposition. The iridium/rhenium coated graphite (Ir/Re/C) specimens were oxidized at elevated temperatures in stagnated air for 3600 s. The purification of the as-prepared Ir coating was higher than about 99.98% with the main impurity elements Si, Al, Fe and Ru. After oxidation, the Ir/Re/C specimens kept integrity without significant failures and the average oxidation rate was about 0.219 mg/(cm{sup 2} min). Pores were found at the grain boundaries and concentrated to penetrating holes with the growth of Ir grains, which resulted in disastrous failures of the Ir coating.

  14. Low Cost High Performance Nanostructured Spectrally Selective Coating

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Sungho [Univ. of California, San Diego, CA (United States)

    2017-04-05

    Sunlight absorbing coating is a key enabling technology to achieve high-temperature high-efficiency concentrating solar power operation. A high-performance solar absorbing material must simultaneously meet all the following three stringent requirements: high thermal efficiency (usually measured by figure of merit), high-temperature durability, and oxidation resistance. The objective of this research is to employ a highly scalable process to fabricate and coat black oxide nanoparticles onto solar absorber surface to achieve ultra-high thermal efficiency. Black oxide nanoparticles have been synthesized using a facile process and coated onto absorber metal surface. The material composition, size distribution and morphology of the nanoparticle are guided by numeric modeling. Optical and thermal properties have been both modeled and measured. High temperature durability has been achieved by using nanocomposites and high temperature annealing. Mechanical durability on thermal cycling have also been investigated and optimized. This technology is promising for commercial applications in next-generation high-temperature concentration solar power (CSP) plants.

  15. An experimental estimation of the resistance against a high-temperature gas corrosion of C/C composite materials with protective plasma coating

    International Nuclear Information System (INIS)

    Babin, S.V.; Khripakov, E.V.

    2007-01-01

    Materials with well-defined structure has been proposed as corrosion- and erosion-resistant coating from the carbon-carbon composite. Experiments on heat and erosion resistance of plasma coatings at carbon-carbon composite materials demonstrate availability of multilayer with upper erosion resistant layer on the basis of aluminium oxide, intermediate layer on the basis of boron-containing components with aluminium additions and damping layer of silicon carbide. Multilayer protective coats offer demand service characteristics of details [ru

  16. Highly efficient high temperature electrolysis

    DEFF Research Database (Denmark)

    Hauch, Anne; Ebbesen, Sune; Jensen, Søren Højgaard

    2008-01-01

    High temperature electrolysis of water and steam may provide an efficient, cost effective and environmentally friendly production of H-2 Using electricity produced from sustainable, non-fossil energy sources. To achieve cost competitive electrolysis cells that are both high performing i.e. minimum...... internal resistance of the cell, and long-term stable, it is critical to develop electrode materials that are optimal for steam electrolysis. In this article electrolysis cells for electrolysis of water or steam at temperatures above 200 degrees C for production of H-2 are reviewed. High temperature...... electrolysis is favourable from a thermodynamic point of view, because a part of the required energy can be supplied as thermal heat, and the activation barrier is lowered increasing the H-2 production rate. Only two types of cells operating at high temperature (above 200 degrees C) have been described...

  17. High temperature corrosion of metals

    International Nuclear Information System (INIS)

    Quadakkers, W.J.; Schuster, H.; Ennis, P.J.

    1988-08-01

    This paper covers three main topics: 1. high temperature oxidation of metals and alloys, 2. corrosion in sulfur containing environments and 3. structural changes caused by corrosion. The following 21 subjects are discussed: Influence of implanted yttrium and lanthanum on the oxidation behaviour of beta-NiA1; influence of reactive elements on the adherence and protective properties of alumina scales; problems related to the application of very fine markers in studying the mechanism of thin scale formation; oxidation behaviour of chromia forming Co-Cr-Al alloys with or without reactive element additions; growth and properties of chromia-scales on high-temperature alloys; quantification of the depletion zone in high temperature alloys after oxidation in process gas; effects of HC1 and of N2 in the oxidation of Fe-20Cr; investigation under nuclear safety aspects of Zircaloy-4 oxidation kinetics at high temperatures in air; on the sulfide corrosion of metallic materials; high temperature sulfide corrosion of Mn, Nb and Nb-Si alloys; corrosion behaviour or NiCrAl-based alloys in air and air-SO2 gas mixtures; sulfidation of cobalt at high temperatures; preoxidation for sulfidation protection; fireside corrosion and application of additives in electric utility boilers; transport properties of scales with complex defect structures; observations of whiskers and pyramids during high temperature corrosion of iron in SO2; corrosion and creep of alloy 800H under simulated coal gasification conditions; microstructural changes of HK 40 cast alloy caused by exploitation in tubes in steam reformer installation; microstructural changes during exposure in corrosive environments and their effect on mechanical properties; coatings against carburization; mathematical modeling of carbon diffusion and carbide precipitation in Ni-Cr-based alloys. (MM)

  18. Effect of high temperature annealing on the grain size of CVD-grown SiC and experimental PBMR TRISO coated particles

    CSIR Research Space (South Africa)

    Mokoduwe, SM

    2010-10-01

    Full Text Available in the PBMR fuel SiC layer. square samples were cut from the original sample received from ORNL and prepared for grain size Prague, Czech Republic, October 18 – 2000 °C. These no significant ion of how the 8] also ge is also of tal THODS -Si... for grain size determination Fig. 5: Influence of high temperature annealing on the CVD ORNL polycrystalline 3 C-SiC. Fig. 6: Influence of high temperature annealing on the polycrystalline 3 C-SiC layer of PBMR TRISO CP batches D and E...

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

    Science.gov (United States)

    Thompson, James

    2015-01-01

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

  20. Anticoking Coatings for High Temperature Petrochemical Reactors Revêtements pour réacteurs pétrochimiques à cokage réduit

    Directory of Open Access Journals (Sweden)

    Ropital F.

    2006-12-01

    Full Text Available Coke deposition is a major problem for several refinery and petrochemical processes, among which steam cracking for ethylene production. Decreasing coking rates will reduce decoking frequency and will also decrease heat transfer degradation. For these processes, a means of reducing coking phenomena is the application of anticoking coatings on the reactor walls. For this purpose a methodology was developed under a CEC Brite-Euram project with steam cracking as the main application. A first selection of the coatings and their techniques of deposition was performed according to their composition (non catalytic compounds, their resistance to carburization and oxidation and also according to the nature of the substrate. The feasibility of coating deposition was studied for small diameter furnace tubes and the techniques were perfected in particular with respect to the physicochemical characterization of the coatings and their resistance during thermal cycling and coking-decoking cycles. For the thermal cycling and the coking evaluation, industrial conditions were reproduced as closely as possible. For coking tests, a microreactor with complete mixing of the gas phase was developed for temperatures up to 950°C. The coking behavior of the coated samples was compared with conventional refractory alloys: reduction of the coking rate by a factor of 3 was measured with the most promising coating. This work was completed by the kinetic modelling of coking on uncoated materials. La formation de coke est un problème crucial pour de nombreux procédés pétrochimiques. Ralentir le cokage permet de réduire la fréquence des décokages et de limiter la dégradation du transfert thermique. Un des moyens envisageables pour réduire le cokage est le dépôt d'un revêtement à la paroi de ces réacteurs. La mise au point de tels revêtements a fait l'objet d'un projet de recherche européen Brite-Euram, pour lequel le vapocraquage a été la principale

  1. Ion filter for high temperature cleaning

    International Nuclear Information System (INIS)

    Kutomi, Yasuhiro; Nakamori, Masaharu.

    1994-01-01

    A porous ceramic pipe mainly comprising alumina is used as a base pipe, and then crud and radioactive ion adsorbing materials in high temperature and high pressure water mainly comprising a FeTiO 3 compound are flame-coated on the outer surface thereof to a film thickness of about 100 to 300μ m as an aimed value by an acetylene flame-coating method. The flame-coated FeTiO 3 layer is also porous, so that high temperature and high pressure water to be cleaned can pass through from the inside to the outside of the pipe. Cruds can be removed and radioactive ions can be adsorbed during passage. Since all the operations can be conducted at high temperature and high pressure state, cooling is no more necessary for the high temperature and high pressure water to be cleaned, heat efficiency of the plant can be improved and a cooling facility can be saved. Further, since the flame-coating of FeTiO 3 to the porous ceramic pipe can be conducted extremely easily compared with production of a sintering product, cost for the production of filter elements can be saved remarkably. (T.M.)

  2. Mixed-carbon-coated LiMn_0_._4Fe_0_._6PO_4 nanopowders with excellent high rate and low temperature performances for lithium-ion batteries

    International Nuclear Information System (INIS)

    Zou, Bang-Kun; Wang, He-Yang; Qiang, Zi-Yue; Shao, Yu; Sun, Xin; Wen, Zhao-Yin; Chen, Chun-Hua

    2016-01-01

    Graphical abstract: Ascorbic acid acts as both an antioxidant and a surfactant to form organic groups (first carbon source) on the surface of as-solvothermal products, in which the −OH (or H_2O) groups of glucose (second carbon source) are closely bonded to the surface to form a uniform adsorption layer. Uniform mixed-carbon-coated LiMn_0_._4Fe_0_._6PO_4 nanopowders are formed after calcination, which demonstrate excellent electrochemical performances. - Highlights: • Ascorbic acid acts as both an antioxidant and a first-time carbon coating source. • Reaction mechanisms of the synthesis are carefully studied. • Mixed-carbon-coated LiMn_0_._4Fe_0_._6PO_4 nanopowders process excellent high rate and low temperature performances. - Abstract: A novel solvothermal approach with ascorbic acid as both an antioxidant and a first-time carbon coating source is developed to synthesize LiMn_0_._4Fe_0_._6PO_4 nano-particles with a uniform particle size distribution around 150 nm. A calcination step for the second-time carbon coating and further crystallization is adopted following the solvothermal step. The structures and electrochemical properties of the obtained samples are studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, Fourier transformation infrared, Infrared carbon-sulfur analyzer and galvanostatic cell cycling. Ascorbic acid plays a crucial role in the formation of uniform carbon layer and nano-particles. Compared with single-carbon-coated LiMn_0_._4Fe_0_._6PO_4 without adding ascorbic acid, the mixed-carbon-coated LiMn_0_._4Fe_0_._6PO_4 shows much better electrochemical performance. It can deliver specific capacities of 154.8 and 128.5 mAh g"−"1 at 1C and 20C, respectively, at 25 °C. Even at −20 °C, its specific capacities are 106.6 and 68.8 mAh g"−"1 at 0.2C and 5C, respectively.

  3. Radiation cured coatings for high performance products

    International Nuclear Information System (INIS)

    Parkins, J.C.; Teesdale, D.H.

    1984-01-01

    Development over the past ten years of radiation curable coating and lacquer systems and the means of curing them has led to new products in the packaging, flooring, furniture and other industries. Solventless lacquer systems formulated with acrylates and other resins enable high levels of durability, scuff resistance and gloss to be achieved. Ultra violet and electron beam radiation curing are used, the choice depending on the nature of the coating, the product and the scale of the operation. (author)

  4. Effect of the deposition temperature on corrosion resistance and biocompatibility of the hydroxyapatite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Vladescu, A., E-mail: alinava@inoe.ro [National Institute for Optoelectronics, 409 Atomistilor Str., Magurele (Romania); Braic, M. [National Institute for Optoelectronics, 409 Atomistilor Str., Magurele (Romania); Azem, F. Ak [Dokuz Eylul University, Engineering Faculty, Metallurgical and Materials Engineering Department, Buca-Izmir (Turkey); Titorencu, I. [Institute of Cellular Biology and Pathology Nicolae Simionescu of the Romanian Academy, 8 B.P.Hasdeu, Bucharest (Romania); Braic, V. [National Institute for Optoelectronics, 409 Atomistilor Str., Magurele (Romania); Pruna, V. [Institute of Cellular Biology and Pathology Nicolae Simionescu of the Romanian Academy, 8 B.P.Hasdeu, Bucharest (Romania); Kiss, A. [National Institute for Optoelectronics, 409 Atomistilor Str., Magurele (Romania); Parau, A.C.; Birlik, I. [Dokuz Eylul University, Engineering Faculty, Metallurgical and Materials Engineering Department, Buca-Izmir (Turkey)

    2015-11-01

    Highlights: • Hydroxyapatite has been produced at temperature from 400 to 800 °C by magnetron sputtering. • Hydroxyapatite crystallinity is improved by increasing substrate temperature. • The increase of substrate temperature resulted in corrosion resistance increasing. • The coating shows high growth of the osteosarcoma cells over a wide temperature range. - Abstract: Hydroxyapatite (HAP) ceramics belong to a class of calcium phosphate-based materials, which have been widely used as coatings on titanium medical implants in order to improve bone fixation and thus to increase the lifetime of the implant. In this study, HAP coatings were deposited from pure HAP targets on Ti6Al4V substrates using the radio-frequency magnetron sputtering technique at substrate temperatures ranging from 400 to 800 °C. The surface morphology and the crystallographic structure of the films were investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The corrosion resistance of the coatings in saliva solution at 37 °C was evaluated by potentiodynamic polarization. Additionally, the human osteosarcoma cell line (MG-63) was used to test the biocompatibility of the coatings. The results showed that all of the coatings grown uniformly and that the increasing substrate temperature induced an increase in their crystallinity. Corrosion performance of the coatings was improved with the increase of the substrate temperature from 400 °C to 800 °C. Furthermore, all the coatings support the attachment and growth of the osteosarcoma cells with regard to the in vitro test findings.

  5. High temperature battery. Hochtemperaturbatterie

    Energy Technology Data Exchange (ETDEWEB)

    Bulling, M.

    1992-06-04

    To prevent heat losses of a high temperature battery, it is proposed to make the incoming current leads in the area of their penetration through the double-walled insulating housing as thermal throttle, particularly spiral ones.

  6. High temperature structural silicides

    International Nuclear Information System (INIS)

    Petrovic, J.J.

    1997-01-01

    Structural silicides have important high temperature applications in oxidizing and aggressive environments. Most prominent are MoSi 2 -based materials, which are borderline ceramic-intermetallic compounds. MoSi 2 single crystals exhibit macroscopic compressive ductility at temperatures below room temperature in some orientations. Polycrystalline MoSi 2 possesses elevated temperature creep behavior which is highly sensitive to grain size. MoSi 2 -Si 3 N 4 composites show an important combination of oxidation resistance, creep resistance, and low temperature fracture toughness. Current potential applications of MoSi 2 -based materials include furnace heating elements, molten metal lances, industrial gas burners, aerospace turbine engine components, diesel engine glow plugs, and materials for glass processing

  7. In-situ fabrication of MoSi{sub 2}/SiC–Mo{sub 2}C gradient anti-oxidation coating on Mo substrate and the crucial effect of Mo{sub 2}C barrier layer at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jun [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Beijing 100084 (China); State Key Laboratory of New Ceramics and Fine Processing, Beijing 100084 (China); Gong, Qianming, E-mail: gongqianming@mail.tsinghua.edu.cn [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Beijing 100084 (China); State Key Laboratory of New Ceramics and Fine Processing, Beijing 100084 (China); Shao, Yang; Zhuang, Daming [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Beijing 100084 (China); State Key Laboratory of New Ceramics and Fine Processing, Beijing 100084 (China); Liang, Ji [Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)

    2014-07-01

    MoSi{sub 2}/SiC–Mo{sub 2}C gradient coating on molybdenum was in situ prepared with pack cementation process by two steps: (1) carburizing with graphite powder to obtain a Mo{sub 2}C layer on Mo substrate, and (2) siliconizing with Si powder to get a composite MoSi{sub 2}/SiC layer on the upper part of Mo{sub 2}C layer. The microstructure and elemental distribution in the coating were investigated with scanning electron microscopy (SEM), backscattered electron (BSE), energy dispersive spectroscopy (EDS), electron probe microanalysis (EPMA) and X-ray diffraction (XRD). Cyclic oxidation tests (at 500 °C, 1200 °C, 1400 °C and 1600 °C) demonstrated excellent oxidation resistance for the gradient composite coating and the mass loss was only 0.23% in 60 min at 1600 °C. XRD, EPMA, thermal dynamic and phase diagram analyses indicated that the Mo{sub 2}C barrier layer played the key role in slowing down the diffusion of C and Si toward inner Mo substrate at high temperature and principally this contributed to the excellent anti-oxidation for Mo besides the outer MoSi{sub 2}/SiC composite layer.

  8. In-situ fabrication of MoSi2/SiC–Mo2C gradient anti-oxidation coating on Mo substrate and the crucial effect of Mo2C barrier layer at high temperature

    International Nuclear Information System (INIS)

    Liu, Jun; Gong, Qianming; Shao, Yang; Zhuang, Daming; Liang, Ji

    2014-01-01

    MoSi 2 /SiC–Mo 2 C gradient coating on molybdenum was in situ prepared with pack cementation process by two steps: (1) carburizing with graphite powder to obtain a Mo 2 C layer on Mo substrate, and (2) siliconizing with Si powder to get a composite MoSi 2 /SiC layer on the upper part of Mo 2 C layer. The microstructure and elemental distribution in the coating were investigated with scanning electron microscopy (SEM), backscattered electron (BSE), energy dispersive spectroscopy (EDS), electron probe microanalysis (EPMA) and X-ray diffraction (XRD). Cyclic oxidation tests (at 500 °C, 1200 °C, 1400 °C and 1600 °C) demonstrated excellent oxidation resistance for the gradient composite coating and the mass loss was only 0.23% in 60 min at 1600 °C. XRD, EPMA, thermal dynamic and phase diagram analyses indicated that the Mo 2 C barrier layer played the key role in slowing down the diffusion of C and Si toward inner Mo substrate at high temperature and principally this contributed to the excellent anti-oxidation for Mo besides the outer MoSi 2 /SiC composite layer.

  9. HTGR fuel behavior at very high temperature

    International Nuclear Information System (INIS)

    Kashimura, Satoru; Ogawa, Touru; Fukuda, Kousaku; Iwamoto, Kazumi

    1986-03-01

    Fuel behavior at very high temperature simulating abnormal transient of the reactor operation and accidents have been investigated on TRISO coating LEU oxide particle fuels at JAERI. The test simulating the abnormal transient was carried out by irradiation of loose coated particles above 1600 deg C. The irradiation test indicated that particle failure was principally caused by kernel migration. For simulation of the core heat-up accident, two experiments of out-of-pile heating were made. Survival temperature limits were measured and fuel performance at very high temperature were investigated by the heatings. Study on the fuel behavior under reactivity initiated accident was made by NSRR(Nuclear Safety Research Reactor) pulse irradiation, where maximum temperature was higher than 2800 deg C. It was found in the pulse irradiation experiments that the coated particles incorporated in the compacts did not so severely fail unlike the loose coated particles at ultra high temperature above 2800 deg C. In the former particles UO 2 material at the center of the kernel vaporized, leaving a spherical void. (author)

  10. Design of an Online Fission Gas Monitoring System for Post-irradiation Examination Heating Tests of Coated Fuel Particles for High-Temperature Gas-Cooled Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Dawn Scates

    2010-10-01

    A new Fission Gas Monitoring System (FGMS) has been designed at the Idaho National Laboratory (INL) for use of monitoring online fission gas-released during fuel heating tests. The FGMS will be used with the Fuel Accident Condition Simulator (FACS) at the Hot Fuels Examination Facility (HFEF) located at the Materials and Fuels Complex (MFC) within the INL campus. Preselected Advanced Gas Reactor (AGR) TRISO (Tri-isotropic) fuel compacts will undergo testing to assess the fission product retention characteristics under high temperature accident conditions. The FACS furnace will heat the fuel to temperatures up to 2,000ºC in a helium atmosphere. Released fission products such as Kr and Xe isotopes will be transported downstream to the FGMS where they will accumulate in cryogenically cooledcollection traps and monitored with High Purity Germanium (HPGe) detectors during the heating process. Special INL developed software will be used to monitor the accumulated fission products and will report data in near real-time. These data will then be reported in a form that can be readily available to the INL reporting database. This paper describes the details of the FGMS design, the control and acqusition software, system calibration, and the expected performance of the FGMS. Preliminary online data may be available for presentation at the High Temperature Reactor (HTR) conference.

  11. Low Temperature Metal Coating Method Final Report CRADA No. TSB-1155-95

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sang-Wook [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gabel, Howard [Innovative Technology, Inc., Santa Barbara, CA (United States)

    2018-01-19

    A new metal coating method, cidled KEM (kinetic energy metal.lization), demonstrated in the laboratory by lnovati, utilized fast-moving solid particIes entrained in a gas that are caused to fiow through a nozzIe to effect particle deposition on metal surfaces at room temperature conditions. This method (US Patent 5,795,626) was an attractive and viabIe alternative to the currentIy available high-temperature coating methods avaiIabIe. Since it differs significantly from existing metal coating technologies, a brief description of the method is incIuded here. The proposed method, KEM, achieves cohesive and adhesive metallurgical bonding through the high-speed coUision of powder with a substrate and the subsequent discharge of electrical charge at the substrate. Such coating is effected by entraining metal powder in a gas and accelerating this mixture through a supersonic nozzle. The gas/powder is directed towards the substrate to be coated. Collisions occur, initiaIly between the powder and the substrate, and, as the first Iayer of the coating forms, between the powder and the coating. During these collisions the powder is rapidly deformed, causing the exposure of fresh (oxide free) active metal surface. When these’active surfaces contact one another, they agglomerate and form true metaIIurgicaI bonds. The resultant coating has Iow porosity and high adhesive and cohesive strength. The formation of metaIIurgicaI bonds is potentiated by the discharge of electrical energy. This electrical energy is the result of triboeIectric charging of the particIes during acceleration and transit to the nozzIe. An advantage of the method is that it does not raise the temperature of the powder being appLiedor that of the substrate. Consequently, materials sensitive to high temperature may be applied without changing Me properties of the materkd or substrate.

  12. Highly Electrically Conducting Glass-Graphene Nanoplatelets Hybrid Coatings.

    Science.gov (United States)

    Garcia, E; Nistal, A; Khalifa, A; Essa, Y; Martín de la Escalera, F; Osendi, M I; Miranzo, P

    2015-08-19

    Hybrid coatings consisting of a heat resistant Y2O3-Al2O3-SiO2 (YAS) glass containing 2.3 wt % of graphene nanoplatelets (GNPs) were developed by flame spraying homogeneous ceramic powders-GNP granules. Around 40% of the GNPs survived the high spraying temperatures and were distributed along the splat-interfaces, forming a percolated network. These YAS-GNP coatings are potentially interesting in thermal protection systems and electromagnetic interference shields for aerospace applications; therefore silicon carbide (SiC) materials at the forefront of those applications were employed as substrates. Whereas the YAS coatings are nonconductive, the YAS-GNP coatings showed in-plane electrical conductivity (∼10(2) S·m(-1)) for which a low percolation limit (below 3.6 vol %) is inferred. Indentation tests revealed the formation of a highly damaged indentation zone showing multiple shear displacements between adjacent splats probably favored by the graphene sheets location. The indentation radial cracks typically found in brittle glass coatings are not detected in the hybrid coatings that are also more compliant.

  13. Low Temperature Cure Powder Coatings (LTCPC)

    Science.gov (United States)

    2010-10-01

    Dr. Glen Merfeld, General Electric Global Research evaluated and optimized the formulation, and cure and performance parameters of candidate LTCPC...Unacceptable test result = Marginal test result = Acceptable test result 80 therefore suffer from brittleness at extremely low temperatures. NASA’s

  14. Detection and control of as-produced pyrocarbon permeability in biso-coated high-temperature gas-cooled reactor fuel particles

    International Nuclear Information System (INIS)

    Stinton, D.P.; Thiele, B.A.; Lackey, W.J.; Morgan, C.S.

    1980-05-01

    About 60 Biso-coated particle batches with coatings deposited in either 0.13- or 0.24-m dia coaters were studied in this work. These batches were carefully characterized for permeability by neon-helium intrusion, long-term chlorination followed by radiography, and fission gas release. These methods of permeability measurement were compared and correlated with deposition conditions as well as pyrocarbon properties. The results from several irradiation tests were also used to evaluate the validity of the permeability measurements. The neon-helium and long-term chlorination techniques correlated very clearly. Coatings with neon-to-helium ratios below 0.3 were gastight by the chlorination procedure, whereas those with ratios above 0.4 were permeable. The fission gas release technique was unable to distinguish between slightly permeable coatings and gastight ones. Therefore, neon-helium and long-term chlorination procedures are preferred over the fission gas release technique. Results from several irradiation tests verified that coatings with neon-to-helium ratios below 0.3 were gastight, whereas those with ratios above about 0.4 were permeable. 10 figures, 2 tables

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

    Energy Technology Data Exchange (ETDEWEB)

    Markwitz, A., E-mail: a.markwitz@gns.cri.nz [Department for Ion Beam Technologies, GNS Science, 30 Gracefield Road, Lower Hutt (New Zealand); The MacDiarmid Institute for Advanced Materials and Nanotechnology (New Zealand); Mohr, B.; Leveneur, J. [Department for Ion Beam Technologies, GNS Science, 30 Gracefield Road, Lower Hutt (New Zealand)

    2014-07-15

    Nanometre-smooth diamond-like carbon coatings (DLC) were produced at room temperature with ion implantation using 6 kV C{sub 3}H{sub y}{sup +} ion beams. Ion beam analysis measurements showed that the coatings contain no heavy Z impurities at the level of 100 ppm, have a homogeneous stoichiometry in depth and a hydrogen concentration of typically 25 at.%. High resolution TEM analysis showed high quality and atomically flat amorphous coatings on wafer silicon. Combined TEM and RBS analysis gave a coating density of 3.25 g cm{sup −3}. Raman spectroscopy was performed to probe for sp{sup 2}/sp{sup 3} bonds in the coatings. The results indicate that low energy ion implantation with 6 kV produces hydrogenated amorphous carbon coatings with a sp{sup 3} content of about 20%. Results highlight the opportunity of developing room temperature DLC coatings with ion beam technology for industrial applications.

  16. High temperature reaction kinetics

    International Nuclear Information System (INIS)

    Jonah, C.D.; Beno, M.F.; Mulac, W.A.; Bartels, D.

    1985-01-01

    During the last year the dependence of the apparent rate of OD + CO on water pressure was measured at 305, 570, 865 and 1223 K. An explanation was found and tested for the H 2 O dependence of the apparent rate of OH(OD) + CO at high temperatures. The isotope effect for OH(D) with CO was determined over the temperature range 330 K to 1225 K. The reason for the water dependence of the rate of OH(OD) + CO near room temperatures has been investigated but no clear explanation has been found. 1 figure

  17. High-temperature superconductivity

    International Nuclear Information System (INIS)

    Ginzburg, V.L.

    1987-07-01

    After a short account of the history of experimental studies on superconductivity, the microscopic theory of superconductivity, the calculation of the control temperature and its possible maximum value are presented. An explanation of the mechanism of superconductivity in recently discovered superconducting metal oxide ceramics and the perspectives for the realization of new high-temperature superconducting materials are discussed. 56 refs, 2 figs, 3 tabs

  18. High temperature pipeline design

    Energy Technology Data Exchange (ETDEWEB)

    Greenslade, J.G. [Colt Engineering, Calgary, AB (Canada). Pipelines Dept.; Nixon, J.F. [Nixon Geotech Ltd., Calgary, AB (Canada); Dyck, D.W. [Stress Tech Engineering Inc., Calgary, AB (Canada)

    2004-07-01

    It is impractical to transport bitumen and heavy oil by pipelines at ambient temperature unless diluents are added to reduce the viscosity. A diluted bitumen pipeline is commonly referred to as a dilbit pipeline. The diluent routinely used is natural gas condensate. Since natural gas condensate is limited in supply, it must be recovered and reused at high cost. This paper presented an alternative to the use of diluent to reduce the viscosity of heavy oil or bitumen. The following two basic design issues for a hot bitumen (hotbit) pipeline were presented: (1) modelling the restart problem, and, (2) establishing the maximum practical operating temperature. The transient behaviour during restart of a high temperature pipeline carrying viscous fluids was modelled using the concept of flow capacity. Although the design conditions were hypothetical, they could be encountered in the Athabasca oilsands. It was shown that environmental disturbances occur when the fluid is cooled during shut down because the ground temperature near the pipeline rises. This can change growing conditions, even near deeply buried insulated pipelines. Axial thermal loads also constrain the design and operation of a buried pipeline as higher operating temperatures are considered. As such, strain based design provides the opportunity to design for higher operating temperature than allowable stress based design methods. Expansion loops can partially relieve the thermal stress at a given temperature. As the design temperature increase, there is a point at which above grade pipelines become attractive options, although the materials and welding procedures must be suitable for low temperature service. 3 refs., 1 tab., 10 figs.

  19. High performance ceria-bismuth bilayer electrolyte low temperature solid oxide fuel cells (LT-SOFCs) fabricated by combining co-pressing with drop-coating

    KAUST Repository

    Hou, Jie; Bi, Lei; Qian, Jing; Zhu, Zhiwen; Zhang, Junyu; Liu, Wei

    2015-01-01

    The Sm0.075Nd0.075Ce0.85O2-δ-Er0.4Bi1.6O3 bilayer structure film, which showed an encouraging performance in LT-SOFCs, was successfully fabricated by a simple low cost technique combining one-step co-pressing with drop-coating.

  20. Protection against corrosion to high temperature by means of rich silicon coatings; Proteccion contra corrosion a alta temperatura por medio de recubrimientos ricos en silicio

    Energy Technology Data Exchange (ETDEWEB)

    Porcayo Calderon, Jesus [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    1999-07-01

    In this research work the study of the process of corrosion by molten salts of sodium sulphate-vanadium pentoxide and its prevention by means of metallic coatings rich in silicon was contemplated. The research encompassed the development of the coating system, the chemical and thermochemical analysis of the system sodium sulphate - vanadium pentoxide, the evaluation of the resistance to the corrosion of the coating system by gravimetric and electrochemistry techniques, and the study of the stability of the coating system - substrate. [Spanish] En este trabajo de investigacion se contempla el estudio del proceso de corrosion por sales fundidas de sulfato de sodio - pentoxido de vanadio y su prevencion por medio de recubrimientos metalicos ricos en silicio. La investigacion abarca el desarrollo del sistema de recubrimientos, el analisis quimico y termoquimico del sistema sulfato de sodio - pentoxido de vanadio, la evaluacion de la resistencia a la corrosion del sistema de recubrimientos por tecnicas gravimetricas y electroquimicas, y el estudio de la estabilidad del sistema recubrimiento - sustrato.

  1. High performance ceria-bismuth bilayer electrolyte low temperature solid oxide fuel cells (LT-SOFCs) fabricated by combining co-pressing with drop-coating

    KAUST Repository

    Hou, Jie

    2015-03-24

    The Sm0.075Nd0.075Ce0.85O2-δ-Er0.4Bi1.6O3 bilayer structure film, which showed an encouraging performance in LT-SOFCs, was successfully fabricated by a simple low cost technique combining one-step co-pressing with drop-coating.

  2. Fabrication of High Transparency Diamond-Like Carbon Film Coating on D263T Glass at Room Temperature as an Antireflection Layer

    Directory of Open Access Journals (Sweden)

    Chii-Ruey Lin

    2013-01-01

    Full Text Available This study intends to deposit high transmittance diamond-like carbon (DLC thin films on D263T glass substrate at room temperature via a diamond powder target using the radio frequency (RF magnetron sputtering technique. Moreover, various process parameters were used to tune the properties of the thin films by using the Taguchi method. Experimental results show that the content of sp3 bonded carbon decreases in accordance with the effect of the substrate temperature. In addition, the hardness of all as-deposited single-layer DLC films ranges from 13.2 to 22.5 GPa, and the RMS surface roughness was improved significantly with the decrease in sputtering pressure. The water repellent of the deposited DLC films improved significantly with the increase of the sp3 content, and its contact angle was larger than that of the noncoated one by 1.45 times. Furthermore, the refraction index (n of all as-deposited DLC films ranges from 1.95 to 2.1 at λ = 600 nm. These results demonstrate that the thickness increased as the reflectance increased. DLC film under an RF power of 150 W possesses high transmissive ability (>81% and low average reflectance ability (<9.5% in the visible wavelengths (at λ = 400–700 nm.

  3. High temperature storage loop :

    Energy Technology Data Exchange (ETDEWEB)

    Gill, David Dennis; Kolb, William J.

    2013-07-01

    A three year plan for thermal energy storage (TES) research was created at Sandia National Laboratories in the spring of 2012. This plan included a strategic goal of providing test capability for Sandia and for the nation in which to evaluate high temperature storage (>650ÀC) technology. The plan was to scope, design, and build a flow loop that would be compatible with a multitude of high temperature heat transfer/storage fluids. The High Temperature Storage Loop (HTSL) would be reconfigurable so that it was useful for not only storage testing, but also for high temperature receiver testing and high efficiency power cycle testing as well. In that way, HTSL was part of a much larger strategy for Sandia to provide a research and testing platform that would be integral for the evaluation of individual technologies funded under the SunShot program. DOEs SunShot program seeks to reduce the price of solar technologies to 6/kWhr to be cost competitive with carbon-based fuels. The HTSL project sought to provide evaluation capability for these SunShot supported technologies. This report includes the scoping, design, and budgetary costing aspects of this effort

  4. High Temperature Electrolysis

    DEFF Research Database (Denmark)

    Elder, Rachael; Cumming, Denis; Mogensen, Mogens Bjerg

    2015-01-01

    High temperature electrolysis of carbon dioxide, or co-electrolysis of carbon dioxide and steam, has a great potential for carbon dioxide utilisation. A solid oxide electrolysis cell (SOEC), operating between 500 and 900. °C, is used to reduce carbon dioxide to carbon monoxide. If steam is also i...

  5. High temperature thermometric phosphors

    Science.gov (United States)

    Allison, Stephen W.; Cates, Michael R.; Boatner, Lynn A.; Gillies, George T.

    1999-03-23

    A high temperature phosphor consists essentially of a material having the general formula LuPO.sub.4 :Dy.sub.(x),Eu.sub.y) wherein: 0.1 wt %.ltoreq.x.ltoreq.20 wt % and 0.1 wt %.ltoreq.y.ltoreq.20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopent. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions.

  6. The behaviour of transport from the fission products caesium and strontium in coated particles for high temperature reactors under irradiation conditions

    International Nuclear Information System (INIS)

    Zoller, P.

    1976-07-01

    At first survey is given about existing knowledge of the behaviour of caesium and strontium fission product transport in coated particles. In order to describe the complicated fission product transport mechanisms under irradiation conditions a suitable calculating model (SLIPPER) is taken over and modified to the special problems of an irradiation experiment. Fundamentally, the fission product transport is represented by the two contributions of diffusion and recoil, at which the diffusion is described by effective diffusion coefficients. In difference of that the possibility of a two-phase-diffusion is examined for the Cs diffusion in the fuel kernel. The model application on measuring results from irradiation experiments of KFA-Juelich and Mol-Belgien allowed the explanation from the characteristic of fission product transport in coated particles under irradiation conditions and produced effective diffusion coefficients for the fission products Cs and Sr. (orig.) [de

  7. Dependence of the surface resistance of niobium coated copper cavities on the coating temperature

    International Nuclear Information System (INIS)

    Darriulat, P.; Durand, C.; Janot, P.; Rensing, N.; Weingarten, W.; Bosland, P.; Gobin, J.; Martignac, J.

    1996-01-01

    Six hydro-formed copper 1.5 GHz cavities have been baked and coated with niobium at different temperatures between 100 deg C and 200 deg C, while keeping the other discharge parameters unchanged. Their surface resistance has been measured as a function RF field and trapped magnetic field. Its dependence on deposition temperature confirms earlier indications obtained using 350 MHz LEP cavities that 150 deg C leads to optimal performances. The critical temperatures of Nb/Cu and bulk niobium cavities have also been measured. (author)

  8. High temperature materials characterization

    Science.gov (United States)

    Workman, Gary L.

    1990-01-01

    A lab facility for measuring elastic moduli up to 1700 C was constructed and delivered. It was shown that the ultrasonic method can be used to determine elastic constants of materials from room temperature to their melting points. The ease in coupling high frequency acoustic energy is still a difficult task. Even now, new coupling materials and higher power ultrasonic pulsers are being suggested. The surface was only scratched in terms of showing the full capabilities of either technique used, especially since there is such a large learning curve in developing proper methodologies to take measurements into the high temperature region. The laser acoustic system does not seem to have sufficient precision at this time to replace the normal buffer rod methodology.

  9. High temperature materials

    International Nuclear Information System (INIS)

    2003-01-01

    The aim of this workshop is to share the needs of high temperature and nuclear fuel materials for future nuclear systems, to take stock of the status of researches in this domain and to propose some cooperation works between the different research organisations. The future nuclear systems are the very high temperature (850 to 1200 deg. C) gas cooled reactors (GCR) and the molten salt reactors (MSR). These systems include not only the reactor but also the fabrication and reprocessing of the spent fuel. This document brings together the transparencies of 13 communications among the 25 given at the workshop: 1) characteristics and needs of future systems: specifications, materials and fuel needs for fast spectrum GCR and very high temperature GCR; 2) high temperature materials out of neutron flux: thermal barriers: materials, resistance, lifetimes; nickel-base metal alloys: status of knowledge, mechanical behaviour, possible applications; corrosion linked with the gas coolant: knowledge and problems to be solved; super-alloys for turbines: alloys for blades and discs; corrosion linked with MSR: knowledge and problems to be solved; 3) materials for reactor core structure: nuclear graphite and carbon; fuel assembly structure materials of the GCR with fast neutron spectrum: status of knowledge and ceramics and cermets needs; silicon carbide as fuel confinement material, study of irradiation induced defects; migration of fission products, I and Cs in SiC; 4) materials for hydrogen production: status of the knowledge and needs for the thermochemical cycle; 5) technologies: GCR components and the associated material needs: compact exchangers, pumps, turbines; MSR components: valves, exchangers, pumps. (J.S.)

  10. Coating Thickness Measurement of the Simulated TRISO-Coated Fuel Particles using an Image Plate and a High Resolution Scanner

    International Nuclear Information System (INIS)

    Kim, Woong Ki; Kim, Yeon Ku; Jeong, Kyung Chai; Lee, Young Woo; Kim, Bong Goo; Eom, Sung Ho; Kim, Young Min; Yeo, Sung Hwan; Cho, Moon Sung

    2014-01-01

    In this study, the thickness of the coating layers of 196 coated particles was measured using an Image Plate detector, high resolution scanner and digital image processing techniques. The experimental results are as follows. - An X-ray image was acquired for 196 simulated TRISO-coated fuel particles with ZrO 2 kernel using an Image Plate with high resolution in a reduced amount of time. - We could observe clear boundaries between coating layers for 196 particles. - The geometric distortion error was compensated for the calculation. - The coating thickness of the TRISO-coated fuel particles can be nondestructively measured using X-ray radiography and digital image processing technology. - We can increase the number of TRISO-coated particles to be inspected by increasing the number of Image Plate detectors. A TRISO-coated fuel particle for an HTGR (high temperature gas-cooled reactor) is composed of a nuclear fuel kernel and outer coating layers. The coating layers consist of buffer PyC (pyrolytic carbon), inner PyC (I-PyC), SiC, and outer PyC (O-PyC) layer. The coating thickness is measured to evaluate the soundness of the coating layers. X-ray radiography is one of the nondestructive alternatives for measuring the coating thickness without generating a radioactive waste. Several billion particles are subject to be loaded in a reactor. A lot of sample particles should be tested as much as possible. The acquired X-ray images for the measurement of coating thickness have included a small number of particles because of the restricted resolution and size of the X-ray detector. We tried to test many particles for an X-ray exposure to reduce the measurement time. In this experiment, an X-ray image was acquired for 196 simulated TRISO-coated fuel particles using an image plate and high resolution scanner with a pixel size of 25Χ25 μm 2 . The coating thickness for the particles could be measured on the image

  11. High temperature radioisotope capsule

    International Nuclear Information System (INIS)

    Bradshaw, G.B.

    1976-01-01

    A high temperature radioisotope capsule made up of three concentric cylinders, with the isotope fuel located within the innermost cylinder is described. The innermost cylinder has hemispherical ends and is constructed of a tantalum alloy. The intermediate cylinder is made of a molybdenum alloy and is capable of withstanding the pressure generated by the alpha particle decay of the fuel. The outer cylinder is made of a platinum alloy of high resistance to corrosion. A gas separates the innermost cylinder from the intermediate cylinder and the intermediate cylinder from the outer cylinder

  12. A Novel Low-Temperature Fiffusion Aluminide Coating for Ultrasupercritical Coal-Fried Boiler Applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ying

    2009-12-31

    An ultrasupercritical (USC) boiler with higher steam temperature and pressure is expected to increase the efficiency of the coal-fired power plant and also decrease emissions of air pollutants. Ferritic/martensitic alloys have been developed with good creep strength for the key components in coal-fired USC plants. However, they typically suffer excessive steam-side oxidation, which contributes to one of main degradation mechanisms along with the fire-side corrosion in coal-fired boilers. As the steam temperature further increases in USC boilers, oxidation of the tube internals becomes an increasing concern, and protective coatings such as aluminide-based diffusion coatings need to be considered. However, conventional aluminizing processes via pack cementation or chemical vapor deposition are typically carried out at elevated temperatures (1000-1150 C). Thermochemical treatment of ferritic/martensitic alloys at such high temperatures could severely degrade their mechanical properties, particularly the alloy's creep resistance. The research focus of this project was to develop an aluminide coating with good oxidation resistance at temperatures {le} 700 C so that the coating processing would not detrimentally alter the creep performance of the ferritic/martensitic alloys. Nevertheless, when the aluminizing temperature is lowered, brittle Al-rich intermetallic phases, such as Fe{sub 2}Al{sub 5} and FeAl{sub 3}, tend to form in the coating, which may reduce the resistance to fatigue cracking. Al-containing binary masteralloys were selected based on thermodynamic calculations to reduce the Al activity in the pack cementation process and thus to prevent the formation of brittle Al-rich intermetallic phases. Thermodynamic computations were carried out using commercial software HSC 5.0 for a series of packs containing various Cr-Al binary masteralloys. The calculation results indicate that the equilibrium partial pressures of Al halides at 700 C were a function of Al

  13. High-temperature uncertainty

    International Nuclear Information System (INIS)

    Timusk, T.

    2005-01-01

    Recent experiments reveal that the mechanism responsible for the superconducting properties of cuprate materials is even more mysterious than we thought. Two decades ago, Georg Bednorz and Alex Mueller of IBM's research laboratory in Zurich rocked the world of physics when they discovered a material that lost all resistance to electrical current at the record temperature of 36 K. Until then, superconductivity was thought to be a strictly low-temperature phenomenon that required costly refrigeration. Moreover, the IBM discovery - for which Bednorz and Mueller were awarded the 1987 Nobel Prize for Physics - was made in a ceramic copper-oxide material that nobody expected to be particularly special. Proposed applications for these 'cuprates' abounded. High-temperature superconductivity, particularly if it could be extended to room temperature, offered the promise of levitating trains, ultra-efficient power cables, and even supercomputers based on superconducting quantum interference devices. But these applications have been slow to materialize. Moreover, almost 20 years on, the physics behind this strange state of matter remains a mystery. (U.K.)

  14. High performance bio-based thermosets for composites and coatings

    Science.gov (United States)

    Paramarta, Adlina Ambeg

    In the recent decade, there has been increasing interest in using renewable feedstocks as chemical commodities for composites and coatings application. Vegetable oils are promising renewable resources due to their wide availability with affordable cost. In fact, the utilization of vegetable oils to produce composite and coatings products has been around for centuries; linseed oil was widely used for wide variety of paints. However, due to its chemical structure, the application of vegetable oils for high-performance materials is limited; and thus chemical modification is necessary. One of the modification approaches is by substituting the glycerol core in the triglycerides with sucrose to form sucrose esters of vegetable oil fatty acids, in which this resin possesses a higher number of functional group per molecule and a more rigid core. In this research, thermosets of highly functionalized sucrose esters of vegetable oils were developed. Two crosslinking methods of epoxidized surcrose soyate (ESS) resins were explored: direct polymerization with anhydride moieties for composite applications and Michael-addition reaction of acrylated-epoxidized sucrose soyate (AESS) for coatings applications. In the first project, it was shown that the reaction kinetics, thermal and mechanical properties of the materials can be tuned by varying the molar ratio between the epoxide and anhydride, plus the type and amount of catalyst. Furthermore, the toughness properties of the ESS-based thermosets can be improved by changing the type of anhydride crosslinkers and incorporating secondary phase rubbers. Then, in the second system, the epoxy functionality in the ESS was converted into acrylate group, which then crosslinked with amine groups through the Michael-addition reaction to produce coatings systems. The high number of functional groups and the fast reactivity of the crosslinker results in coatings that can be cured at ambient temperature, yet still possess moderately high glass

  15. Strand Burner Results of AFP-001 Propellant with Inert Coating for Temperature Compensation

    Science.gov (United States)

    2015-10-01

    there were 4 different configurations: baseline, a C-100 coated, an SC-11 coated, and a urethane acrylate (UA) coated. C-100 is a polyurea based...coating, SC-11 is an epoxy-based coating, and UA is a urethane- acrylate -based coating. These coatings were chosen to target a specific strength...Ignition was achieved by running current through a nichrome wire placed on top of the sample. Events were recorded with a Phantom high-speed camera

  16. Fabrication and Microstructure of Hydroxyapatite Coatings on Zirconia by Room Temperature Spray Process.

    Science.gov (United States)

    Seo, Dong Seok; Chae, Hak Cheol; Lee, Jong Kook

    2015-08-01

    Hydroxyapatite coatings were fabricated on zirconia substrates by a room temperature spray process and were investigated with regards to their microstructure, composition and dissolution in water. An initial hydroxyapatite powder was prepared by heat treatment of bovine-bone derived powder at 1100 °C for 2 h, while dense zirconia substrates were fabricated by pressing 3Y-TZP powder and sintering it at 1350 °C for 2 h. Room temperature spray coating was performed using a slit nozzle in a low pressure-chamber with a controlled coating time. The phase composition of the resultant hydroxyapatite coatings was similar to that of the starting powder, however, the grain size of the hydroxyapatite particles was reduced to about 100 nm due to their formation by particle impaction and fracture. All areas of the coating had a similar morphology, consisting of reticulated structure with a high surface roughness. The hydroxyapatite coating layer exhibited biostability in a stimulated body fluid, with no severe dissolution being observed during in vitro experimentation.

  17. High critical temperature superconducting composite and fabrication process

    International Nuclear Information System (INIS)

    Dubots, P.; Legat, D.

    1989-01-01

    The core comprises a high temperature superconducting sintered oxide coated with alumina or barium oxide covered with a first sheath in aluminum, a second sheath in niobium and a third sheath in copper [fr

  18. Inorganic Nanostructured High-Temperature Magnet Wires, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will develop a high-temperature tolerant electrically-insulating coating for magnet wires. The Phase I program will result in a flexible, inorganic...

  19. High Temperature Piezoelectric Drill

    Science.gov (United States)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom

    2012-01-01

    Venus is one of the planets in the solar systems that are considered for potential future exploration missions. It has extreme environment where the average temperature is 460 deg C and its ambient pressure is about 90 atm. Since the existing actuation technology cannot maintain functionality under the harsh conditions of Venus, it is a challenge to perform sampling and other tasks that require the use of moving parts. Specifically, the currently available electromagnetic actuators are limited in their ability to produce sufficiently high stroke, torque, or force. In contrast, advances in developing electro-mechanical materials (such as piezoelectric and electrostrictive) have enabled potential actuation capabilities that can be used to support such missions. Taking advantage of these materials, we developed a piezoelectric actuated drill that operates at the temperature range up to 500 deg C and the mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) configuration. The detailed results of our study are presented in this paper

  20. Failure mechanisms in high temperature gas cooled reactor fuel particles

    International Nuclear Information System (INIS)

    Soo, P.; Uneberg, G.; Sabatini, R.L.; Schweitzer, D.G.

    1979-01-01

    BISO coated UO 2 and ThO 2 particles were heated to high temperatures to determine failure mechanisms during hypothetical loss of coolant scenarios. Rapid failure begins when the oxides are reduced to liquid carbides. Several failure mechanisms are applicable, ranging from hole and crack formation in the coatings to catastrophic particle disintegration

  1. High temperature materials and mechanisms

    CERN Document Server

    2014-01-01

    The use of high-temperature materials in current and future applications, including silicone materials for handling hot foods and metal alloys for developing high-speed aircraft and spacecraft systems, has generated a growing interest in high-temperature technologies. High Temperature Materials and Mechanisms explores a broad range of issues related to high-temperature materials and mechanisms that operate in harsh conditions. While some applications involve the use of materials at high temperatures, others require materials processed at high temperatures for use at room temperature. High-temperature materials must also be resistant to related causes of damage, such as oxidation and corrosion, which are accelerated with increased temperatures. This book examines high-temperature materials and mechanisms from many angles. It covers the topics of processes, materials characterization methods, and the nondestructive evaluation and health monitoring of high-temperature materials and structures. It describes the ...

  2. Dense nanostructured t-ZrO2 coatings at low temperatures via modified emulsion precipitation

    NARCIS (Netherlands)

    Woudenberg, F.C.M.; Sager, W.F.C.; Sibelt, N.G.M.; Verweij, H.

    2001-01-01

    Nanostructured coatings on metals, plastics, and textiles have numerous applications, for example, as antifogging and self-cleaning coatings as well as protective coatings against corrosion, heat, or wear. Here the preparation at low temperature of dense nanostructured tetragonal ZrO2 coatings via a

  3. Improving Erosion Resistance of Plasma-Sprayed Ceramic Coatings by Elevating the Deposition Temperature Based on the Critical Bonding Temperature

    Science.gov (United States)

    Yao, Shu-Wei; Yang, Guan-Jun; Li, Cheng-Xin; Li, Chang-Jiu

    2018-01-01

    Interlamellar bonding within plasma-sprayed coatings is one of the most important factors dominating the properties and performance of coatings. The interface bonding between lamellae significantly influences the erosion behavior of plasma-sprayed ceramic coatings. In this study, TiO2 and Al2O3 coatings with different microstructures were deposited at different deposition temperatures based on the critical bonding temperature concept. The erosion behavior of ceramic coatings was investigated. It was revealed that the coatings prepared at room temperature exhibit a typical lamellar structure with numerous unbonded interfaces, whereas the coatings deposited at the temperature above the critical bonding temperature present a dense structure with well-bonded interfaces. The erosion rate decreases sharply with the improvement of interlamellar bonding when the deposition temperature increases to the critical bonding temperature. In addition, the erosion mechanisms of ceramic coatings were examined. The unbonded interfaces in the conventional coatings act as pre-cracks accelerating the erosion of coatings. Thus, controlling interlamellar bonding formation based on the critical bonding temperature is an effective approach to improve the erosion resistance of plasma-sprayed ceramic coatings.

  4. High temperature superconductors

    CERN Document Server

    Paranthaman, Parans

    2010-01-01

    This essential reference provides the most comprehensive presentation of the state of the art in the field of high temperature superconductors. This growing field of research and applications is currently being supported by numerous governmental and industrial initiatives in the United States, Asia and Europe to overcome grid energy distribution issues. The technology is particularly intended for densely populated areas. It is now being commercialized for power-delivery devices, such as power transmission lines and cables, motors and generators. Applications in electric utilities include current limiters, long transmission lines and energy-storage devices that will help industries avoid dips in electric power.

  5. High temperature interface superconductivity

    International Nuclear Information System (INIS)

    Gozar, A.; Bozovic, I.

    2016-01-01

    Highlight: • This review article covers the topic of high temperature interface superconductivity. • New materials and techniques used for achieving interface superconductivity are discussed. • We emphasize the role played by the differences in structure and electronic properties at the interface with respect to the bulk of the constituents. - Abstract: High-T_c superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-T_c Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both ‘passive’ hetero-structures as well as surface-induced effects by external gating are discussed. We conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.

  6. High temperature metallic recuperator

    Science.gov (United States)

    Ward, M. E.; Solmon, N. G.; Smeltzer, C. E.

    1981-06-01

    An industrial 4.5 MM Btu/hr axial counterflow recuperator, fabricated to deliver 1600 F combustion air, was designed to handle rapid cyclic loading, a long life, acceptable costs, and a low maintenance requirement. A cost benefit anlysis of a high temperature waste heat recovery system utilizing the recurperator and components capable of 1600 F combustion air preheat shows that this system would have a payback period of less than two years. Fifteen companies and industrial associations were interviewed and expressed great interest in recuperation in large energy consuming industries. Determination of long term environmental effects on candidate recuperator tubing alloys was completed. Alloys found to be acceptable in the 2200 F flue gas environment of a steel billet reheat furnace, were identified.

  7. New cermet coatings for mid-temperature applications for solar concentrated combine heat and power system

    OpenAIRE

    Wäckelgård, Ewa; Bartali, Ruben; Gerosa, Riccardo; Laidani, Nadhira; Mattsson, Andreas; Micheli, Victor; Rivolta, Barbara

    2014-01-01

    New cermet (ceramic-metal) composite coatings have been developed for solar absorbers in a solar concentrating system for combined heat and power operating in a mid-temperature range between 250 to 350 degrees C. The coatings were applied on stainless steel substrates. Two types of cermet with expected good duration properties were chosen: Nb-TiO2 and W-SiO2. The basic layer-structure concept consisted of four sub-layers, counted from the substrate: molybdenum infrared reflector, high metal c...

  8. High-temperature materials and structural ceramics

    International Nuclear Information System (INIS)

    1990-01-01

    This report gives a survey of research work in the area of high-temperature materials and structural ceramics of the KFA (Juelich Nuclear Research Center). The following topics are treated: (1) For energy facilities: ODS materials for gas turbine blades and heat exchangers; assessment of the remaining life of main steam pipes, material characterization and material stress limits for First-Wall components; metallic and graphitic materials for high-temperature reactors. (2) For process engineering plants: composites for reformer tubes and cracking tubes; ceramic/ceramic joints and metal/ceramic and metal/metal joints; Composites and alloys for rolling bearing and sliding systems up to application temperatures of 1000deg C; high-temperature corrosion of metal and ceramic material; porous ceramic high-temperature filters and moulding coat-mix techniques; electrically conducting ceramic material (superconductors, fuel cells, solid electrolytes); high-temperature light sources (high-temperature chemistry); oil vapor engines with caramic components; ODS materials for components in diesel engines and vehicle gas turbines. (MM) [de

  9. Selectively coated high efficiency glazing for solar-thermal flat-plate collectors

    International Nuclear Information System (INIS)

    Ehrmann, N.; Reineke-Koch, R.

    2012-01-01

    In order to increase the efficiency of solar-thermal flat-plate collectors at temperatures above 100 °C or with low solar irradiation, we implement a double glazing with a low-emitting (low-e) coating on the inner pane to improve the insulation of the transparent cover. Since commercially available low-e glazing provides only insufficient solar transmittance for the application in thermal flat-plate collectors we are developing a sputter-deposited low e-coating system based on transparent conductive oxides which provides a high solar transmittance of 85% due to additional antireflective coatings and the use of low-iron glass substrates. Durability tests of the developed coating system show that our low e-coating system is well suitable even at high temperatures, humidity and condensation.

  10. High-mobility ultrathin semiconducting films prepared by spin coating.

    Science.gov (United States)

    Mitzi, David B; Kosbar, Laura L; Murray, Conal E; Copel, Matthew; Afzali, Ali

    2004-03-18

    The ability to deposit and tailor reliable semiconducting films (with a particular recent emphasis on ultrathin systems) is indispensable for contemporary solid-state electronics. The search for thin-film semiconductors that provide simultaneously high carrier mobility and convenient solution-based deposition is also an important research direction, with the resulting expectations of new technologies (such as flexible or wearable computers, large-area high-resolution displays and electronic paper) and lower-cost device fabrication. Here we demonstrate a technique for spin coating ultrathin (approximately 50 A), crystalline and continuous metal chalcogenide films, based on the low-temperature decomposition of highly soluble hydrazinium precursors. We fabricate thin-film field-effect transistors (TFTs) based on semiconducting SnS(2-x)Se(x) films, which exhibit n-type transport, large current densities (>10(5) A cm(-2)) and mobilities greater than 10 cm2 V(-1) s(-1)--an order of magnitude higher than previously reported values for spin-coated semiconductors. The spin-coating technique is expected to be applicable to a range of metal chalcogenides, particularly those based on main group metals, as well as for the fabrication of a variety of thin-film-based devices (for example, solar cells, thermoelectrics and memory devices).

  11. High-mobility ultrathin semiconducting films prepared by spin coating

    Science.gov (United States)

    Mitzi, David B.; Kosbar, Laura L.; Murray, Conal E.; Copel, Matthew; Afzali, Ali

    2004-03-01

    The ability to deposit and tailor reliable semiconducting films (with a particular recent emphasis on ultrathin systems) is indispensable for contemporary solid-state electronics. The search for thin-film semiconductors that provide simultaneously high carrier mobility and convenient solution-based deposition is also an important research direction, with the resulting expectations of new technologies (such as flexible or wearable computers, large-area high-resolution displays and electronic paper) and lower-cost device fabrication. Here we demonstrate a technique for spin coating ultrathin (~50Å), crystalline and continuous metal chalcogenide films, based on the low-temperature decomposition of highly soluble hydrazinium precursors. We fabricate thin-film field-effect transistors (TFTs) based on semiconducting SnS2-xSex films, which exhibit n-type transport, large current densities (>105Acm-2) and mobilities greater than 10cm2V-1s-1-an order of magnitude higher than previously reported values for spin-coated semiconductors. The spin-coating technique is expected to be applicable to a range of metal chalcogenides, particularly those based on main group metals, as well as for the fabrication of a variety of thin-film-based devices (for example, solar cells, thermoelectrics and memory devices).

  12. Anti-biofilm efficacy of low temperature processed AgCl–TiO2 nanocomposite coating

    International Nuclear Information System (INIS)

    Naik, Kshipra; Kowshik, Meenal

    2014-01-01

    Biofilms are a major concern in the medical settings and food industries due to their high tolerance to antibiotics, biocides and mechanical stress. Currently, the development of novel methods to control biofilm formation is being actively pursued. In the present study, sol–gel coatings of AgCl–TiO 2 nanoparticles are presented as potential anti-biofilm agents, wherein TiO 2 acts as a good supporting matrix to prevent aggregation of silver and facilitates its controlled release. Low-temperature processed AgCl–TiO 2 nanocomposite coatings inhibit biofilm formation by Escherichia coli, Staphylococcus epidermidis and Pseudomonas aeruginosa. In vitro biofilm assay experiments demonstrated that AgCl–TiO 2 nanocomposite coated surfaces, inhibited the development of biofilms over a period of 10 days as confirmed by scanning electron microscopy. The silver release kinetics exhibited an initial high release, followed by a slow and sustained release. The anti-biofilm efficacy of the coatings could be attributed to the release of silver, which prevents the initial bacterial adhesion required for biofilm formation. - Highlights: • Potential of AgCl–TiO 2 nanocomposite coating to inhibit biofilm formation is exhibited. • Initial rapid release followed by later slow and sustained release of silver obtained. • TiO 2 being porous and inorganic in nature acts as a good supporting matrix

  13. Studies on antimony absorption on Carbon steel (CS) and magnetite coated CS at high temperature to investigate the problem of out of core Sb activity in PHWRs

    International Nuclear Information System (INIS)

    Keny, S.J.; Gokhale, B.K.; Kumbhar, A.G.; Bera, Santanu; Velmurugan, S.

    2014-01-01

    Sb from PHT (primary heat transfer) pump bearings of PHWRs (Pressurized Heavy Water Reactors) goes to the reactor core and gets activated to 121 Sb and 123 Sb. Subsequently, it deposits on out of core surface resulting in radiation exposure to station personnel's apparent high decontamination factors. Sb, thus deposited can't be impassivated by normal decontamination process. Earlier studies indicates lattice substitution of Sb +3 for Fe +2 in magnetite at low doping levels (≤5%). This process, at reactor conditions is yet to be well understood. To formulate an adequate decontamination formulation and methodology and for having insight at Sb deposition mechanism under rector conditions studies are performed

  14. Influence of substrate temperature on properties of MgF2 coatings

    International Nuclear Information System (INIS)

    Yu Hua; Qi Hongji; Cui Yun; Shen Yanming; Shao Jianda; Fan Zhengxiu

    2007-01-01

    Thermal boat evaporation was employed to prepare MgF 2 single-layer coatings upon both JGS1 and UBK7 substrates at different substrate temperatures. Microstructure, transmittance and residual stress of these coatings were measured by X-ray diffraction, spectrophotometer, and optical interferometer, respectively. Measurement of laser induced damage threshold (LIDT) of the samples was performed at 355 nm, 8 ns pulses. The results showed that high substrate temperature was beneficial to crystallization of the film. Above 244 deg. C, the refractive index increased gradually with the substrate temperature rising. Whereas, it was exceptional at 210 deg. C that the refractive index was higher than those deposited at 244 and 277 deg. C. The tensile residual stresses were exhibited in all MgF 2 films, but not well correlated with the substrate temperature. In addition, the stresses were comparatively smaller upon JGS1 substrates. A tendency could be seen that the LIDTs reached the highest values at about 244 deg. C, and the films upon JGS1 had higher LIDTs than those upon UBK7 substrates at the same temperature. Meanwhile, the damage morphologies showed that the laser damage of the coating resulted from an absorbing center at the film-substrate interface. The features of the damages were displayed by an absorbing center dominated model. Furthermore, the reason of the difference in LIDT values was discussed in detail

  15. Advances in high temperature chemistry

    CERN Document Server

    Eyring, Leroy

    1969-01-01

    Advances in High Temperature Chemistry, Volume 2 covers the advances in the knowledge of the high temperature behavior of materials and the complex and unfamiliar characteristics of matter at high temperature. The book discusses the dissociation energies and free energy functions of gaseous monoxides; the matrix-isolation technique applied to high temperature molecules; and the main features, the techniques for the production, detection, and diagnosis, and the applications of molecular beams in high temperatures. The text also describes the chemical research in streaming thermal plasmas, as w

  16. High emittance black nickel coating on copper substrate for space applications

    Energy Technology Data Exchange (ETDEWEB)

    Somasundaram, Soniya, E-mail: jrf0013@isac.gov.in; Pillai, Anju M., E-mail: anjum@isac.gov.in; Rajendra, A., E-mail: rajendra@isac.gov.in; Sharma, A.K., E-mail: aks@isac.gov.in

    2015-09-15

    Highlights: • High emittance black nickel coating is obtained on copper substrate. • The effect of various process parameters on IR emittance is studied systematically. • Process parameters are optimized to develop a high emittance black nickel coating. • Coating obtained using the finalized parameters exhibited an emittance of 0.83. • SEM and EDAX are used for coating characterization. - Abstract: Black nickel, an alloy coating of zinc and nickel, is obtained on copper substrate by pulse electrodeposition from a modified Fishlock bath containing nickel sulphate, nickel ammonium sulphate, zinc sulphate and ammonium thiocyanate. A nickel undercoat of 4–5 μm thickness is obtained using Watts bath to increase the corrosion resistance and adhesion of the black nickel coating. The effect of bath composition, temperature, solution pH, current density and plating time on the coating appearance and corresponding infra-red emittance of the coating is investigated systematically. Process parameters are optimized to develop a high emittance space worthy black nickel coating to improve the heat radiation characteristics. The effect of the chemistry of the plating bath on the coating composition was studied using energy dispersive X-ray analysis (EDAX) of the coatings. The 5–6 μm thick uniform jet black zinc–nickel alloy coating obtained with optimized process exhibited an emittance of 0.83 and an absorbance of 0.92. The zinc to nickel ratio of black nickel coatings showing high emittance and appealing appearance was found to be in the range 2.3–2.4.

  17. Materials corrosion and protection at high temperatures

    International Nuclear Information System (INIS)

    Balbaud, F.; Desgranges, Clara; Martinelli, Laure; Rouillard, Fabien; Duhamel, Cecile; Marchetti, Loic; Perrin, Stephane; Molins, Regine; Chevalier, S.; Heintz, O.; David, N.; Fiorani, J.M.; Vilasi, M.; Wouters, Y.; Galerie, A.; Mangelinck, D.; Viguier, B.; Monceau, D.; Soustelle, M.; Pijolat, M.; Favergeon, J.; Brancherie, D.; Moulin, G.; Dawi, K.; Wolski, K.; Barnier, V.; Rebillat, F.; Lavigne, O.; Brossard, J.M.; Ropital, F.; Mougin, J.

    2011-01-01

    This book was made from the lectures given in 2010 at the thematic school on 'materials corrosion and protection at high temperatures'. It gathers the contributions from scientists and engineers coming from various communities and presents a state-of-the-art of the scientific and technological developments concerning the behaviour of materials at high temperature, in aggressive environments and in various domains (aerospace, nuclear, energy valorization, and chemical industries). It supplies pedagogical tools to grasp high temperature corrosion thanks to the understanding of oxidation mechanisms. It proposes some protection solutions for materials and structures. Content: 1 - corrosion costs; macro-economical and metallurgical approach; 2 - basic concepts of thermo-chemistry; 3 - introduction to the Calphad (calculation of phase diagrams) method; 4 - use of the thermodynamic tool: application to pack-cementation; 5 - elements of crystallography and of real solids description; 6 - diffusion in solids; 7 - notions of mechanics inside crystals; 8 - high temperature corrosion: phenomena, models, simulations; 9 - pseudo-stationary regime in heterogeneous kinetics; 10 - nucleation, growth and kinetic models; 11 - test experiments in heterogeneous kinetics; 12 - mechanical aspects of metal/oxide systems; 13 - coupling phenomena in high temperature oxidation; 14 - other corrosion types; 15 - methods of oxidized surfaces analysis at micro- and nano-scales; 16 - use of SIMS in the study of high temperature corrosion of metals and alloys; 17 - oxidation of ceramics and of ceramic matrix composite materials; 18 - protective coatings against corrosion and oxidation; 19 - high temperature corrosion in the 4. generation of nuclear reactor systems; 20 - heat exchangers corrosion in municipal waste energy valorization facilities; 21 - high temperature corrosion in oil refining and petrochemistry; 22 - high temperature corrosion in new energies industry. (J.S.)

  18. Evaluation of the Commercial off-the-shelf (COTS) Low Temperature Powder Coating (LTPC)

    Science.gov (United States)

    2017-11-15

    CONTRACT NUMBER: FA8532-17-C-0008 (CDRL A001) Evaluation of the Commercial off- the-shelf (COTS) Low Temperature Powder Coating (LTPC...3 Evaluation of the COTS LTPC (CDRL A001) BATTELLE 1 1.0 Introduction...primers in traditional coating systems is costly, time consuming , and represents a risk to health, safety, and the environment. Powder coatings

  19. Life assessment of PVD based hard coatings by linear sweep voltammetry for high performance industrial application

    International Nuclear Information System (INIS)

    Malik, M.; Alam, S.; Irfan, M.; Hassan, Z.

    2006-01-01

    PVD based hard coatings have remarkable achievements in order to improve Tribological and surface properties of coating tools and dies. As PVD based hard coatings have a wide range of industrial applications especially in aerospace and automobile parts where they met different chemical attacks and in order to improve industrial performance these coatings must provide an excellent resistance against corrosion, high temperature oxidation and chemical reaction. This paper focuses on study of behaviour of PVD based hard coatings under different corrosive environments like as H/sub 2/SO/sub 4/, HCl, NaCl, KCl, NaOH etc. Corrosion rate was calculate under linear sweep voltammetry method where the Tafel extrapolation curves used for continuously monitoring the corrosion rate. The results show that these coatings have an excellent resistance against chemical attack. (author)

  20. Small grain size zirconium-based coatings deposited by magnetron sputtering at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, O., E-mail: omar.jimenez.udg@gmail.com [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, AP 307, CP 45101 Zapopan, Jal (Mexico); Department of Materials Science and Engineering, The University of Sheffield, Sheffield S1 3JD (United Kingdom); Audronis, M.; Leyland, A. [Department of Materials Science and Engineering, The University of Sheffield, Sheffield S1 3JD (United Kingdom); Flores, M.; Rodriguez, E. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, AP 307, CP 45101 Zapopan, Jal (Mexico); Kanakis, K.; Matthews, A. [Department of Materials Science and Engineering, The University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2015-09-30

    Hard, partly amorphous, ZrTiB(N) coatings were deposited by Physical Vapour Deposition (PVD) onto (111) silicon wafers at low substrate temperatures of 85 and 110 °C using Closed Field Unbalanced Magnetron Sputtering. A segmented rectangular sputter target composed of three pieces (Zr/TiB{sub 2}/Zr) was used as the source of evaporation of coating components. Two different substrate biases (i.e. floating potential and − 50 V) and N{sub 2} reactive-gas flow rates of 2, 4 and 6 sccm were employed as the main deposition parameter variables. The chemical composition, structure, morphology and mechanical properties were investigated using a variety of analytical techniques such as Glow-Discharge Optical Emission Spectroscopy, cross-sectional Scanning Electron Microscopy (SEM), Glancing Angle X-ray Diffraction (GAXRD) and nanoindentation. With other parameters fixed, coating properties were found to be dependent on the substrate negative bias and nitrogen flow rate. Linear scan profiles and SEM imaging revealed that all coatings were smooth, dense and featureless (in fracture cross section) with no apparent columnar morphology or macro-defects. GAXRD structural analysis revealed that mostly metallic phases were formed for coatings containing no nitrogen, whereas a solid solution (Zr,Ti)N single phase nitride was found in most of the reactively deposited coatings — exhibiting a very small grain size due to nitrogen and boron grain refinement effects. Hardness values from as low as 8.6 GPa up to a maximum of 25.9 GPa are related mainly to solid solution strengthening effects. The measured elastic moduli correlated with the trends in hardness behaviour; values in the range of 120–200 GPa were observed depending on the selected deposition parameters. Also, high H/E values (> 0.1) were achieved with several of the coatings.

  1. High-Temperature Piezoelectric Sensing

    Directory of Open Access Journals (Sweden)

    Xiaoning Jiang

    2013-12-01

    Full Text Available Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented.

  2. Advanced thermal barrier coatings for operation in high hydrogen content fueled gas turbines.

    Energy Technology Data Exchange (ETDEWEB)

    Sampath, Sanjay [Stony Brook Univ., NY (United States)

    2015-04-02

    The Center for Thermal Spray Research (CTSR) at Stony Brook University in partnership with its industrial Consortium for Thermal Spray Technology is investigating science and technology related to advanced metallic alloy bond coats and ceramic thermal barrier coatings for applications in the hot section of gasified coal-based high hydrogen turbine power systems. In conjunction with our OEM partners (GE and Siemens) and through strategic partnership with Oak Ridge National Laboratory (ORNL) (materials degradation group and high temperature materials laboratory), a systems approach, considering all components of the TBC (multilayer ceramic top coat, metallic bond coat & superalloy substrate) is being taken during multi-layered coating design, process development and subsequent environmental testing. Recent advances in process science and advanced in situ thermal spray coating property measurement enabled within CTSR has been incorporated for full-field enhancement of coating and process reliability. The development of bond coat processing during this program explored various aspects of processing and microstructure and linked them to performance. The determination of the bond coat material was carried out during the initial stages of the program. Based on tests conducted both at Stony Brook University as well as those carried out at ORNL it was determined that the NiCoCrAlYHfSi (Amdry) bond coats had considerable benefits over NiCoCrAlY bond coats. Since the studies were also conducted at different cycling frequencies, thereby addressing an associated need for performance under different loading conditions, the Amdry bond coat was selected as the material of choice going forward in the program. With initial investigations focused on the fabrication of HVOF bond coats and the performance of TBC under furnace cycle tests , several processing strategies were developed. Two-layered HVOF bond coats were developed to render optimal balance of density and surface roughness

  3. High temperature superconductor accelerator magnets

    NARCIS (Netherlands)

    van Nugteren, J.

    2016-01-01

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding 20T. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and

  4. Effect of elevated substrate temperature deposition on the mechanical losses in tantala thin film coatings

    Science.gov (United States)

    Vajente, G.; Birney, R.; Ananyeva, A.; Angelova, S.; Asselin, R.; Baloukas, B.; Bassiri, R.; Billingsley, G.; Fejer, M. M.; Gibson, D.; Godbout, L. J.; Gustafson, E.; Heptonstall, A.; Hough, J.; MacFoy, S.; Markosyan, A.; Martin, I. W.; Martinu, L.; Murray, P. G.; Penn, S.; Roorda, S.; Rowan, S.; Schiettekatte, F.; Shink, R.; Torrie, C.; Vine, D.; Reid, S.; Adhikari, R. X.

    2018-04-01

    Brownian thermal noise in dielectric multilayer coatings limits the sensitivity of current and future interferometric gravitational wave detectors. In this work we explore the possibility of improving the mechanical losses of tantala, often used as the high refractive index material, by depositing it on a substrate held at elevated temperature. Promising results have been previously obtained with this technique when applied to amorphous silicon. We show that depositing tantala on a hot substrate reduced the mechanical losses of the as-deposited coating, but subsequent thermal treatments had a larger impact, as they reduced the losses to levels previously reported in the literature. We also show that the reduction in mechanical loss correlates with increased medium range order in the atomic structure of the coatings using x-ray diffraction and Raman spectroscopy. Finally, a discussion is included on our results, which shows that the elevated temperature deposition of pure tantala coatings does not appear to reduce mechanical loss in a similar way to that reported in the literature for amorphous silicon; and we suggest possible future research directions.

  5. High temperature materials; Materiaux a hautes temperatures

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    The aim of this workshop is to share the needs of high temperature and nuclear fuel materials for future nuclear systems, to take stock of the status of researches in this domain and to propose some cooperation works between the different research organisations. The future nuclear systems are the very high temperature (850 to 1200 deg. C) gas cooled reactors (GCR) and the molten salt reactors (MSR). These systems include not only the reactor but also the fabrication and reprocessing of the spent fuel. This document brings together the transparencies of 13 communications among the 25 given at the workshop: 1) characteristics and needs of future systems: specifications, materials and fuel needs for fast spectrum GCR and very high temperature GCR; 2) high temperature materials out of neutron flux: thermal barriers: materials, resistance, lifetimes; nickel-base metal alloys: status of knowledge, mechanical behaviour, possible applications; corrosion linked with the gas coolant: knowledge and problems to be solved; super-alloys for turbines: alloys for blades and discs; corrosion linked with MSR: knowledge and problems to be solved; 3) materials for reactor core structure: nuclear graphite and carbon; fuel assembly structure materials of the GCR with fast neutron spectrum: status of knowledge and ceramics and cermets needs; silicon carbide as fuel confinement material, study of irradiation induced defects; migration of fission products, I and Cs in SiC; 4) materials for hydrogen production: status of the knowledge and needs for the thermochemical cycle; 5) technologies: GCR components and the associated material needs: compact exchangers, pumps, turbines; MSR components: valves, exchangers, pumps. (J.S.)

  6. High Temperature Superconductor Resonator Detectors

    Data.gov (United States)

    National Aeronautics and Space Administration — High Temperature Superconductor (HTS) infrared detectors were studied for years but never matured sufficiently for infusion into instruments. Several recent...

  7. High Temperature Superconductor Machine Prototype

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Træholt, Chresten

    2011-01-01

    A versatile testing platform for a High Temperature Superconductor (HTS) machine has been constructed. The stationary HTS field winding can carry up to 10 coils and it is operated at a temperature of 77K. The rotating armature is at room temperature. Test results and performance for the HTS field...

  8. Tribological behavior and self-healing functionality of TiNbCN-Ag coatings in wide temperature range

    Science.gov (United States)

    Bondarev, A. V.; Kiryukhantsev-Korneev, Ph. V.; Levashov, E. A.; Shtansky, D. V.

    2017-02-01

    Ag- and Nb-doped TiCN coatings with about 2 at.% of Nb and Ag contents varied between 4.0 and 15.1 at.% were designed as promising materials for tribological applications in a wide temperature range. We report on the structure, mechanical, and tribological properties of TiNbCN-Ag coatings fabricated by simultaneous co-sputtering of TiC0.5 + 10%Nb2C and Ag targets in comparison with those of Ag-free coating. The tribological characteristics were evaluated during constant-temperature tests both at room temperature and 300 °C, as well as during dynamic temperature ramp tests in the range of 25-700 °C. The coating structure and elemental composition were studied by means of X-ray diffraction, scanning and transmission electron microscopy, and glow discharge optical emission spectroscopy. The coating microstructures and elemental compositions inside wear tracks, as well as the wear products, were examined by scanning electron microscopy, energy-dispersive spectroscopy, and Raman spectroscopy. We demonstrate that simultaneous alloying with Nb and Ag permits to overcome the main drawbacks of TiCN coatings such as their relatively high values of friction coefficient at elevated temperatures and low oxidation resistance. It is shown that a relatively high amount of Ag (15 at.%) is required to provide enhanced tribological behavior in a wide temperature range of 25-700 °C. In addition, the prepared Ag-doped coatings demonstrated active oxidation protection and self-healing functionality due to the segregation of Ag metallic particles in damage areas such as cracks, pin-holes, or oxidation sites.

  9. Thermal barrier coatings (TBC's) for high heat flux thrust chambers

    Science.gov (United States)

    Bradley, Christopher M.

    -section components has become critical, but at the same time the service conditions have put our best alloy systems to their limits. As a result, implementation of cooling holes and thermal barrier coatings are new advances in hot-section technologies now looked at for modifications to reach higher temperature applications. Current thermal barrier coatings used in today's turbine applications is known as 8%yttria-stabilized zirconia (YSZ) and there are no coatings for current thrust chambers. Current research is looking at the applicability of 8%yttria-stabilized hafnia (YSH) for turbine applications and the implementation of 8%YSZ onto thrust chambers. This study intends to determine if the use of thermal barrier coatings are applicable for high heat flux thrust chambers using industrial YSZ will be advantageous for improvements in efficiency, thrust and longer service life by allowing the thrust chambers to be used more than once.

  10. High heat flux testing of TiC coated molybdenum with a tungsten intermediate layer

    International Nuclear Information System (INIS)

    Fujitsuka, Masakazu; Fukutomi, Masao; Okada, Masatoshi

    1988-01-01

    The use of low atomic number (Z) material coatings for fusion reactor first-wall components has proved to be a valuable technique to reduce the plasma radiation losses. Molybdenum coated with titanium carbide is considered very promising since it has a good capability of receiving heat from the plasma. An interfacial reaction between the TiC film and the molybdenum substrate, however, causes a severe deterioration of the film at elevated temperatures. In order to solve this problem a TiC coated molybdenum with an intermediate tungsten layer was developed. High temperature properties of this material was evaluated by a newly devised electron beam heating apparatus. TiC coatings prepared on a vacuum-heat-treated molybdenum with a tungsten intermediate layer showed good high temperature stability and survived 2.0 s pulses of heating at a power density as high as 53 MW/m 2 . The melt area of the TiC coatings in high heat flux testings also markedly decreased when a tungsten intermediate layer was applied. The melting mechanism of the TiC coatings with and without a tungsten intermediate layer was discussed by EPMA measurements. (author)

  11. Antireflectance coating on shielding window glasses using glacial acetic acid at ambient temperature

    International Nuclear Information System (INIS)

    Sathi Sasidharan, N.; Deshingkar, D.S.; Wattal, P.K.

    2006-01-01

    High density lead glasses having thickness of several centimeters and large dimensions are used as shielding windows in hot cells. To improve visibility, the reflection of light from its optically polished surfaces needs to be minimized to improve transmission as absorption of light in the thick glasses can not be avoided. Antireflectance coating of a material having low refractive index is required for this purpose. Selective leaching of lead at ambient temperature in glacial acetic acid develops a silica rich leached layer on glass surface. Since silica has low refractive index, the leached layer serves as antireflectance coating. Two optically polished discs of shielding window glasses were leached in glacial acetic acid at ambient temperature for 2, 5 and 10 days and their reflectance and transmittance spectra were taken to find effect of leaching. For transparent glass transmittance could be improved from 78.76% to 85.31% after 10 days leaching. Reflectance from the glass could be decreased from 12.48 to 11.67%. For coloured glass transmittance improved from 87.77% to 88.24% after 5 days leaching while reflectance decreased from 12.28% to 5.6% during same period. Based on data generated, 10 days leaching time is recommended for developing anti reflectance coating on transparent shielding window glass and 5 days for coloured shielding window glass. The procedure can be used for shielding windows of any dimensions by fabrication a PVC tank of slightly high dimensions and filling with acetic acid (author)

  12. Tribological behavior and self-healing functionality of TiNbCN-Ag coatings in wide temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Bondarev, A.V., E-mail: abondarev88@gmail.com; Kiryukhantsev-Korneev, Ph.V.; Levashov, E.A.; Shtansky, D.V., E-mail: shtansky@shs.misis.ru

    2017-02-28

    Highlights: • TiNbCN–Ag coatings for wide temperature range tribological applications. • Alloying with Nb and Ag improve tribological properties and oxidation resistance. • Ag-rich TiNbCN coatings show friction coefficient below 0.45 in range of 25–700 °C. • Ag-doped coatings show active oxidation protection and self-healing functionality. - Abstract: Ag- and Nb-doped TiCN coatings with about 2 at.% of Nb and Ag contents varied between 4.0 and 15.1 at.% were designed as promising materials for tribological applications in a wide temperature range. We report on the structure, mechanical, and tribological properties of TiNbCN-Ag coatings fabricated by simultaneous co-sputtering of TiC{sub 0.5} + 10%Nb{sub 2}C and Ag targets in comparison with those of Ag-free coating. The tribological characteristics were evaluated during constant-temperature tests both at room temperature and 300 °C, as well as during dynamic temperature ramp tests in the range of 25–700 °C. The coating structure and elemental composition were studied by means of X-ray diffraction, scanning and transmission electron microscopy, and glow discharge optical emission spectroscopy. The coating microstructures and elemental compositions inside wear tracks, as well as the wear products, were examined by scanning electron microscopy, energy-dispersive spectroscopy, and Raman spectroscopy. We demonstrate that simultaneous alloying with Nb and Ag permits to overcome the main drawbacks of TiCN coatings such as their relatively high values of friction coefficient at elevated temperatures and low oxidation resistance. It is shown that a relatively high amount of Ag (15 at.%) is required to provide enhanced tribological behavior in a wide temperature range of 25–700 °C. In addition, the prepared Ag-doped coatings demonstrated active oxidation protection and self-healing functionality due to the segregation of Ag metallic particles in damage areas such as cracks, pin-holes, or oxidation sites.

  13. Bimodular high temperature planar oxygen gas sensor

    Directory of Open Access Journals (Sweden)

    Xiangcheng eSun

    2014-08-01

    Full Text Available A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs thin film coated yttria-stabilized zirconia (YSZ substrate. The thin film was prepared by radio frequency (r.f. magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO nanoparticles film was characterized by atomic force microscopy (AFM and scanning electron microscopy (SEM. X-ray diffraction (XRD patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500 °C, 600 °C and 800 °C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors.

  14. The effect of zinc bath temperature on the morphology, texture and corrosion behaviour of industrially produced hot-dip galvanized coatings

    Directory of Open Access Journals (Sweden)

    A. Bakhtiari

    2014-03-01

    Full Text Available The purpose of this work is to identify the influence of zinc bath temperature on the morphology, texture and corrosion behavior of hot-dip galvanized coatings. Hot-dip galvanized samples were prepared at temperature in the range of 450-480 °C in steps of 10 °C, which is the conventional galvanizing temperature range in the galvanizing industries. The morphology of coatings was examined with optical microscopy and scanning electron microscopy (SEM. The composition of the coating layers was determined using energy dispersive spectroscopy (EDS analysis. The texture of the coatings was evaluated using X-ray diffraction. Corrosion behavior was performed using salt spray cabinet test and Tafel extrapolation test. From the experimental results, it was found that increasing the zinc bath temperature affects the morphology of the galvanized coatings provoking the appearance of cracks in the coating structure. These cracks prevent formation of a compact structure. In addition, it was concluded that (00.2 basal plane texture component was weakened by increasing the zinc bath temperature and, conversely, appearance of (10.1 prism component, (20.1 high angle pyramidal component and low angle component prevailed. Besides, coatings with strong (00.2 texture component and weaker (20.1 components have better corrosion resistance than the coatings with weak (00.2 and strong (20.1 texture components. Furthermore, corrosion resistance of the galvanized coatings was decreased by increasing the zinc bath temperature.

  15. Optimization of High Porosity Thermal Barrier Coatings Generated with a Porosity Former

    Czech Academy of Sciences Publication Activity Database

    Medřický, J.; Curry, N.; Pala, Zdeněk; Vilémová, Monika; Chráska, Tomáš; Johansson, J.; Markocsan, N.

    2015-01-01

    Roč. 24, č. 4 (2015), s. 622-628 ISSN 1059-9630 R&D Projects: GA ČR GB14-36566G Institutional support: RVO:61389021 Keywords : gas turbine s * high temperature application * porosity of coatings * stabilized zirconia * thermal barrier coatings (TBCs) Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.568, year: 2015

  16. Study on microstructure and high temperature wear resistance of laser cladded nuclear valve clack

    International Nuclear Information System (INIS)

    Zhang Chunliang; Chen Zichen

    2002-01-01

    Laser cladding of Co-base alloy on the nuclear valve-sealing surface are performed with a 5 kW CO 2 transverse flowing laser. The microstructure and the high temperature impact-slide wear resistance of the laser cladded coating and the plasma cladded coating are studied. The results show that the microstructure, the dilution rate and the high temperature impact-slide wear resistance of the laser cladded coating have obvious advantages over the spurt cladding processing

  17. Modeling FBG sensors sensitivity from cryogenic temperatures to room temperature as a function of metal coating thickness

    Science.gov (United States)

    Vendittozzi, Cristian; Felli, Ferdinando; Lupi, Carla

    2018-05-01

    Fiber optics with photo-imprinted Bragg grating have been studied in order to be used as temperature sensors in cryogenic applications. The main disadvantage presented by Fiber Bragg Grating (FBG) sensors is the significant drop in sensitivity as temperature decreases, mainly due to the critical lowering of the thermo-optic coefficient of the fiber and the very low thermal expansion coefficient (CTE) of fused silica at cryogenic temperatures. Thus, especially for the latter, it is important to enhance sensitivity to temperature by depositing a metal coating presenting higher CTE. In this work the thermal sensitivity of metal-coated FBG sensors has been evaluated by considering their elongation within temperature variations in the cryogenic range, as compared to bare fiber sensors. To this purpose, a theoretical model simulating elongation of metal-coated sensors has been developed. The model has been used to evaluate the behaviour of different metals which can be used as coating (Ni, Cu, Al, Zn, Pb and In). The optimal coating thickness has been calculated at different fixed temperature (from 5 K to 100 K) for each metal. It has been found that the metal coating effectiveness depends on thickness and operating temperature in accordance to our previous experimental work and theory suggest.

  18. High Thermal Conductivity of Copper Matrix Composite Coatings with Highly-Aligned Graphite Nanoplatelets

    Science.gov (United States)

    Tagliaferri, Vincenzo; Ucciardello, Nadia

    2017-01-01

    Nanocomposite coatings with highly-aligned graphite nanoplatelets in a copper matrix were successfully fabricated by electrodeposition. For the first time, the disposition and thermal conductivity of the nanofiller has been evaluated. The degree of alignment and inclination of the filling materials has been quantitatively evaluated by polarized micro-Raman spectroscopy. The room temperature values of the thermal conductivity were extracted for the graphite nanoplatelets by the dependence of the Raman G-peak frequency on the laser power excitation. Temperature dependency of the G-peak shift has been also measured. Most remarkable is the global thermal conductivity of 640 ± 20 W·m−1·K−1 (+57% of copper) obtained for the composite coating by the flash method. Our experimental results are accounted for by an effective medium approximation (EMA) model that considers the influence of filler geometry, orientation, and thermal conductivity inside a copper matrix. PMID:29068424

  19. Highly Damping Hard Coatings for Protection of Titanium Blades

    National Research Council Canada - National Science Library

    Movchan, Boris A; Ustinov, Anatolii I

    2005-01-01

    Sn-Cr-MgO system is used as an example to show the basic capability to produce by EBPVD protective metal-ceramic coatings with a high adhesion strength, high values of hardness and damping capacity...

  20. Advanced High Temperature Structural Seals

    Science.gov (United States)

    Newquist, Charles W.; Verzemnieks, Juris; Keller, Peter C.; Rorabaugh, Michael; Shorey, Mark

    2002-10-01

    This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles. Successful development will contribute significantly to the mission goal of reducing launch cost for small, 200 to 300 pound payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature (3100 F) flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs.

  1. Development of a Room Temperature SAW Methane Gas Sensor Incorporating a Supramolecular Cryptophane A Coating

    Directory of Open Access Journals (Sweden)

    Wen Wang

    2016-01-01

    Full Text Available A new room temperature supra-molecular cryptophane A (CrypA-coated surface acoustic wave (SAW sensor for sensing methane gas is presented. The sensor is composed of differential resonator-oscillators, a supra-molecular CrypA coated along the acoustic propagation path, and a frequency signal acquisition module (FSAM. A two-port SAW resonator configuration with low insertion loss, single resonation mode, and high quality factor was designed on a temperature-compensated ST-X quartz substrate, and as the feedback of the differntial oscillators. Prior to development, the coupling of modes (COM simulation was conducted to predict the device performance. The supramolecular CrypA was synthesized from vanillyl alcohol using a double trimerisation method and deposited onto the SAW propagation path of the sensing resonators via different film deposition methods. Experiential results indicate the CrypA-coated sensor made using a dropping method exhibits higher sensor response compared to the unit prepared by the spinning approach because of the obviously larger surface roughness. Fast response and excellent repeatability were observed in gas sensing experiments, and the estimated detection limit and measured sensitivity are ~0.05% and ~204 Hz/%, respectively.

  2. HIGH TEMPERATURE POLYMER FUEL CELLS

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Qingfeng, Li; He, Ronghuan

    2003-01-01

    This paper will report recent results from our group on polymer fuel cells (PEMFC) based on the temperature resistant polymer polybenzimidazole (PBI), which allow working temperatures up to 200°C. The membrane has a water drag number near zero and need no water management at all. The high working...

  3. Phosphor-Doped Thermal Barrier Coatings Deposited by Air Plasma Spray for In-Depth Temperature Sensing

    Directory of Open Access Journals (Sweden)

    Di Peng

    2016-09-01

    Full Text Available Yttria-stabilized zirconia (YSZ-based thermal barrier coating (TBC has been integrated with thermographic phosphors through air plasma spray (APS for in-depth; non-contact temperature sensing. This coating consisted of a thin layer of Dy-doped YSZ (about 40 µm on the bottom and a regular YSZ layer with a thickness up to 300 µm on top. A measurement system has been established; which included a portable; low-cost diode laser (405 nm; a photo-multiplier tube (PMT and the related optics. Coating samples with different topcoat thickness were calibrated in a high-temperature furnace from room temperature to around 900 °C. The results convincingly showed that the current sensor and the measurement system was capable of in-depth temperature sensing over 800 °C with a YSZ top layer up to 300 µm. The topcoat thickness was found to have a strong effect on the luminescent signal level. Therefore; the measurement accuracy at high temperatures was reduced for samples with thick topcoats due to strong light attenuation. However; it seemed that the light transmissivity of YSZ topcoat increased with temperature; which would improve the sensor’s performance at high temperatures. The current sensor and the measurement technology have shown great potential in on-line monitoring of TBC interface temperature.

  4. A novel graded bioactive high adhesion implant coating

    International Nuclear Information System (INIS)

    Brohede, Ulrika; Zhao, Shuxi; Lindberg, Fredrik; Mihranyan, Albert; Forsgren, Johan; Stromme, Maria; Engqvist, Hakan

    2009-01-01

    One method to increase the clinical success rate of metal implants is to increase their bone bonding properties, i.e. to develop a bone bioactive surface leading to reduced risks of interfacial problems. Much research has been devoted to modifying the surface of metals to make them become bioactive. Many of the proposed methods include depositing a coating on the implant. However, there is a risk of coating failure due to low substrate adhesion. This paper describes a method to obtain bioactivity combined with a high coating adhesion via a gradient structure of the coating. Gradient coatings were deposited on Ti (grade 5) using reactive magnetron sputtering with increasing oxygen content. To increase the grain size in the coating, all coatings were post annealed at 385 deg. C. The obtained coating exhibited a gradual transition over 70 nm from crystalline titanium oxide (anatase) at the surface to metallic Ti in the substrate, as shown using cross-section transmission electron microscopy and X-ray photoelectron spectroscopy depth profiling. Using scratch testing, it could be shown that the adhesion to the substrate was well above 1 GPa. The bioactivity of the coating was verified in vitro by the spontaneous formation of hydroxylapatite upon storage in phosphate buffer solution at 37 deg. C for one week. The described process can be applied to implants irrespective of bulk metal in the base and should introduce the possibility to create safer permanent implants like reconstructive devices, dental, or spinal implants.

  5. High Temperature Materials Laboratory (HTML)

    Data.gov (United States)

    Federal Laboratory Consortium — The six user centers in the High Temperature Materials Laboratory (HTML), a DOE User Facility, are dedicated to solving materials problems that limit the efficiency...

  6. Understanding the Role of Temperature and Cathode Composition on Interface and Bulk: Optimizing Aluminum Oxide Coatings for Li-Ion Cathodes.

    Science.gov (United States)

    Han, Binghong; Paulauskas, Tadas; Key, Baris; Peebles, Cameron; Park, Joong Sun; Klie, Robert F; Vaughey, John T; Dogan, Fulya

    2017-05-03

    Surface coating of cathode materials with Al 2 O 3 has been shown to be a promising method for cathode stabilization and improved cycling performance at high operating voltages. However, a detailed understanding on how coating process and cathode composition change the chemical composition, morphology, and distribution of coating within the cathode interface and bulk lattice is still missing. In this study, we use a wet-chemical method to synthesize a series of Al 2 O 3 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 and LiCoO 2 cathodes treated under various annealing temperatures and a combination of structural characterization techniques to understand the composition, homogeneity, and morphology of the coating layer and the bulk cathode. Nuclear magnetic resonance and electron microscopy results reveal that the nature of the interface is highly dependent on the annealing temperature and cathode composition. For Al 2 O 3 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 , higher annealing temperature leads to more homogeneous and more closely attached coating on cathode materials, corresponding to better electrochemical performance. Lower Al 2 O 3 coating content is found to be helpful to further improve the initial capacity and cyclability, which can greatly outperform the pristine cathode material. For Al 2 O 3 -coated LiCoO 2 , the incorporation of Al into the cathode lattice is observed after annealing at high temperatures, implying the transformation from "surface coatings" to "dopants", which is not observed for LiNi 0.5 Co 0.2 Mn 0.3 O 2 . As a result, Al 2 O 3 -coated LiCoO 2 annealed at higher temperature shows similar initial capacity but lower retention compared to that annealed at a lower temperature, due to the intercalation of surface alumina into the bulk layered structure forming a solid solution.

  7. Measurements of internal stresses in bond coating using high energy x-rays from synchrotron radiation source

    CERN Document Server

    Suzuki, K; Akiniwa, Y; Nishio, K; Kawamura, M; Okado, H

    2002-01-01

    Thermal barrier coating (TBC) techniques enable high temperature combustion of turbines made of Ni-base alloy. TBC is made of zirconia top coating on NiCoCrAlY bond coating. The internal stresses in the bond coating play essential role in the delamination or fracture of TBC in service. With the X-rays from laboratory equipments, it is impossible to measure nondestructively the internal stress in the bond coating under the top coating. synchrotron radiations with a high energy and high brightness have a large penetration depth as compared with laboratory X-rays. Using the high energy X-rays from the synchrotron radiation, it is possible to measure the internal stress in the bond coating through the top coating. In this study, the furnace, which can heat a specimen to 1473 K, was developed for the stress measurement of the thermal barrier coatings. The internal stresses in the bond coating were measured at the room temperature, 773 K, 1073 K and 1373 K by using the 311 diffraction from Ni sub 3 Al with about 73...

  8. High temperature divertor plasma operation

    International Nuclear Information System (INIS)

    Ohyabu, Nobuyoshi.

    1991-02-01

    High temperature divertor plasma operation has been proposed, which is expected to enhance the core energy confinement and eliminates the heat removal problem. In this approach, the heat flux is guided through divertor channel to a remote area with a large target surface, resulting in low heat load on the target plate. This allows pumping of the particles escaping from the core and hence maintaining of the high divertor temperature, which is comparable to the core temperature. The energy confinement is then determined by the diffusion coefficient of the core plasma, which has been observed to be much lower than the thermal diffusivity. (author)

  9. High temperature high vacuum creep testing facilities

    International Nuclear Information System (INIS)

    Matta, M.K.

    1985-01-01

    Creep is the term used to describe time-dependent plastic flow of metals under conditions of constant load or stress at constant high temperature. Creep has an important considerations for materials operating under stresses at high temperatures for long time such as cladding materials, pressure vessels, steam turbines, boilers,...etc. These two creep machines measures the creep of materials and alloys at high temperature under high vacuum at constant stress. By the two chart recorders attached to the system one could register time and temperature versus strain during the test . This report consists of three chapters, chapter I is the introduction, chapter II is the technical description of the creep machines while chapter III discuss some experimental data on the creep behaviour. Of helium implanted stainless steel. 13 fig., 3 tab

  10. High efficiency graphene coated copper based thermocells connected in series

    Science.gov (United States)

    Sindhuja, Mani; Indubala, Emayavaramban; Sudha, Venkatachalam; Harinipriya, Seshadri

    2018-04-01

    Conversion of low-grade waste heat into electricity had been studied employing single thermocell or flowcells so far. Graphene coated copper electrodes based thermocells connected in series displayed relatively high efficiency of thermal energy harvesting. The maximum power output of 49.2W/m2 for normalized cross sectional electrode area is obtained at 60ºC of inter electrode temperature difference. The relative carnot efficiency of 20.2% is obtained from the device. The importance of reducing the mass transfer and ion transfer resistance to improve the efficiency of the device is demonstrated. Degradation studies confirmed mild oxidation of copper foil due to corrosion caused by the electrolyte.

  11. High Efficiency Graphene Coated Copper Based Thermocells Connected in Series

    Directory of Open Access Journals (Sweden)

    Mani Sindhuja

    2018-04-01

    Full Text Available Conversion of low-grade waste heat into electricity had been studied employing single thermocell or flowcells so far. Graphene coated copper electrodes based thermocells connected in series displayed relatively high efficiency of thermal energy harvesting. The maximum power output of 49.2 W/m2 for normalized cross sectional electrode area is obtained at 60°C of inter electrode temperature difference. The relative carnot efficiency of 20.2% is obtained from the device. The importance of reducing the mass transfer and ion transfer resistance to improve the efficiency of the device is demonstrated. Degradation studies confirmed mild oxidation of copper foil due to corrosion caused by the electrolyte.

  12. Evaluation of a Low Temperature Cure Powder Coating

    Science.gov (United States)

    2008-05-01

    4”x6”x1/4” Al 2024-T3 panels were chromate conversion coated by NDCEE per MIL-DTL-5514F Type 1 Class A  Reserved for LTCPC  27 – 4”x6”x1/4” Al...2024-T3 panels were chromate conversion coated by FRC Southeast per MIL-DTL- 5514F Type 1 Class A  Reserved for baseline coating JSEM - May...conducted under contract W74V8H- 04-D-0005 Task 427. DISCLAIMER: The contents of this document are not to be used for advertising , publication, or

  13. Annealing temperature effect on electrical properties of MEH-PPV thin film via spin coating method

    Science.gov (United States)

    Azhar, N. E. A.; Shariffudin, S. S.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.

    2018-05-01

    Organic semiconductor has been discovered in different application devices such as organic light emitting diodes (OLEDs). Poly [2-methoxy-5(2' -ethylhexyloxy)-1, 4-phenylenevinylene), MEH-PPV widely used in this device because its ability to produce a good optical quality films. The MEH-PPV was prepared on glass substrate by spin coating method. The thin film was investigated at different annealing temperatures. The scanning electron micrographs (SEM) revealed that sample annealed at 50°C showed uniformity and less aggregation on morphology polymer thin film. Optical properties showed the intensities of visible emission increased as temperatures increased. The current-voltage (I-V) measurement revealed that the temperature of 50°C showed high conductive and it is suitable for optoelectronic device.

  14. Oleate coating of iron oxide nanoparticles in aqueous systems: the role of temperature and surfactant concentration

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Hans-Christian; Schwaminger, Sebastian; Fraga García, Paula; Ritscher, Jonathan; Berensmeier, Sonja, E-mail: s.berensmeier@tum.de [Technische Universität München, Bioseparation Engineering Group (Germany)

    2016-04-15

    Coating magnetic nanoparticles (MNPs) with sodium oleate (SO) is known to be an excellent method to create biocompatible, stable colloids with a narrow size distribution. However, the mechanism of oleate adsorption on the MNP surface in aqueous systems, as well as its influence on colloidal stability, is not yet fully understood. In this context, we present here a physico-chemical study to provide a deeper understanding of surfactant interaction mechanisms with nanoparticles. We examined the effect of temperature and the SO/MNP ratio (w/w) on the adsorption process in water and observed the existence of a maximum for the adsorbed oleate amount at lower temperatures, whereas at higher temperatures, the isotherm can be adapted to the Langmuir model with constant capacity after saturation. The oleate load on the MNP surface was quantified using reversed-phase high-performance liquid chromatography measurements of samples in solution. The thermogravimetric analyses of the solid residues together with infrared spectroscopy analyses indicate a bilayer-similar structure at the MNP/water interface even for low oleate loads. The oleate interacts with the iron oxide surface through a bidentate coordination of the carboxyl group. Zeta potential measurements demonstrate the high stability of the coated system. The maximal oleate load per unit mass of MNPs reaches approximately 0.35 g{sub oleate} g{sub MNP}{sup −1}.Graphical abstract.

  15. Erosion–corrosion and corrosion properties of DLC coated low temperature Erosion–corrosion and corrosion properties of DLC coated low temperature

    DEFF Research Database (Denmark)

    Jellesen, Morten Stendahl; Christiansen, Thomas; Hilbert, Lisbeth Rischel

    2009-01-01

    of AISI 316 as substrate for DLC coatings are investigated. Corrosion and erosion–corrosion measurements were carried out on low temperature nitrided stainless steel AISI 316 and on low temperature nitrided stainless steel AISI 316 with a top layer of DLC. The combination of DLC and low temperature...... nitriding dramatically reduces the amount of erosion–corrosion of stainless steel under impingement of particles in a corrosive medium....

  16. The oxidation behavior of classical thermal barrier coatings exposed to extreme temperature

    Directory of Open Access Journals (Sweden)

    Alina DRAGOMIRESCU

    2017-03-01

    Full Text Available Thermal barrier coatings (TBC are designed to protect metal surfaces from extreme temperatures and improve their resistance to oxidation during service. Currently, the most commonly used systems are those that have the TBC structure bond coat (BC / top coat (TC layers. The top coat layer is a ceramic layer. Oxidation tests are designed to identify the dynamics of the thermally oxide layer (TGO growth at the interface of bond coat / top coat layers, delamination mechanism and the TBC structural changes induced by thermal conditions. This paper is a short study on the evolution of aluminum oxide protective layer along with prolonged exposure to the testing temperature. There have been tested rectangular specimens of metal super alloy with four surfaces coated with a duplex thermal barrier coating system. The specimens were microscopically and EDAX analyzed before and after the tests. In order to determine the oxide type, the samples were analyzed using X-ray diffraction. The results of the investigation are encouraging for future studies. The results show a direct relationship between the development of the oxide layer and long exposure to the test temperature. Future research will focus on changing the testing temperature to compare the results.

  17. Effect of Annealing Temperature and Spin Coating Speed on Mn-Doped ZnS Nanocrystals Thin Film by Spin Coating

    Directory of Open Access Journals (Sweden)

    Noor Azie Azura Mohd Arif

    2017-01-01

    Full Text Available ZnS:Mn nanocrystals thin film was fabricated at 300°C and 500°C via the spin coating method. Its sol-gel was spin coated for 20 s at 3000 rpm and 4000 rpm with metal tape being used to mold the shape of the thin film. A different combination of these parameters was used to investigate their influences on the fabrication of the film. Optical and structural characterizations have been performed. Optical characterization was analyzed using UV-visible spectroscopy and photoluminescence spectrophotometer while the structural and compositional analysis of films was measured via field emission scanning electron microscopy and energy dispersive X-ray. From UV-vis spectra, the wavelength of the ZnS:Mn was 250 nm and the band gap was within the range 4.43 eV–4.60 eV. In room temperature PL spectra, there were two emission peaks centered at 460 nm and 590 nm. Under higher annealing temperature and higher speed used in spin coating, an increase of 0.05 eV was observed. It was concluded that the spin coating process is able to synthesize high quality spherical ZnS:Mn nanocrystals. This conventional process can replace other high technology methods due to its synthesis cost.

  18. High temperature electronic gain device

    International Nuclear Information System (INIS)

    McCormick, J.B.; Depp, S.W.; Hamilton, D.J.; Kerwin, W.J.

    1979-01-01

    An integrated thermionic device suitable for use in high temperature, high radiation environments is described. Cathode and control electrodes are deposited on a first substrate facing an anode on a second substrate. The substrates are sealed to a refractory wall and evacuated to form an integrated triode vacuum tube

  19. RPC operation at high temperature

    CERN Document Server

    Aielli, G; Cardarelli, R; Di Ciaccio, A; Di Stante, L; Liberti, B; Paoloni, A; Pastori, E; Santonico, R

    2003-01-01

    The resistive electrodes of RPCs utilised in several current experiments (ATLAS, CMS, ALICE, BABAR and ARGO) are made of phenolic /melaminic polymers, with room temperature resistivities ranging from 10**1**0 Omega cm, for high rate operation in avalanche mode, to 5 multiplied by 10**1**1 Omega cm, for streamer mode operation at low rate. The resistivity has however a strong temperature dependence, decreasing exponentially with increasing temperature. We have tested several RPCs with different electrode resistivities in avalanche as well as in streamer mode operation. The behaviours of the operating current and of the counting rate have been studied at different temperatures. Long-term operation has also been studied at T = 45 degree C and 35 degree C, respectively, for high and low resistivity electrodes RPCs.

  20. HIgh Temperature Photocatalysis over Semiconductors

    Science.gov (United States)

    Westrich, Thomas A.

    Due in large part to in prevalence of solar energy, increasing demand of energy production (from all sources), and the uncertain future of petroleum energy feedstocks, solar energy harvesting and other photochemical systems will play a major role in the developing energy market. This dissertation focuses on a novel photochemical reaction process: high temperature photocatalysis (i.e., photocatalysis conducted above ambient temperatures, T ≥ 100°C). The overarching hypothesis of this process is that photo-generated charge carriers are able to constructively participate in thermo-catalytic chemical reactions, thereby increasing catalytic rates at one temperature, or maintaining catalytic rates at lower temperatures. The photocatalytic oxidation of carbon deposits in an operational hydrocarbon reformer is one envisioned application of high temperature photocatalysis. Carbon build-up during hydrocarbon reforming results in catalyst deactivation, in the worst cases, this was shown to happen in a period of minutes with a liquid hydrocarbon. In the presence of steam, oxygen, and above-ambient temperatures, carbonaceous deposits were photocatalytically oxidized over very long periods (t ≥ 24 hours). This initial experiment exemplified the necessity of a fundamental assessment of high temperature photocatalytic activity. Fundamental understanding of the mechanisms that affect photocatalytic activity as a function of temperatures was achieved using an ethylene photocatalytic oxidation probe reaction. Maximum ethylene photocatalytic oxidation rates were observed between 100 °C and 200 °C; the maximum photocatalytic rates were approximately a factor of 2 larger than photocatalytic rates at ambient temperatures. The loss of photocatalytic activity at temperatures above 200 °C is due to a non-radiative multi-phonon recombination mechanism. Further, it was shown that the fundamental rate of recombination (as a function of temperature) can be effectively modeled as a

  1. High temperature thermoelectric energy conversion

    International Nuclear Information System (INIS)

    Wood, C.

    1986-01-01

    Considerable advances were made in the late '50's and early early '60's in the theory and development of materials for high-temperature thermoelectric energy conversion. This early work culminated in a variety of materials, spanning a range of temperatures, with the product of the figure of merit, Z, and temperature, T, i.e., the dimensionless figure of merit, ZT, of the order of one. This experimental limitation appeared to be universal and led a number of investigators to explore the possibility that a ZT - also represents a theoretical limitation. It was found not to be so

  2. Damage process of high purity tungsten coatings by hydrogen beam heat loads

    International Nuclear Information System (INIS)

    Tamura, S.; Tokunaga, K.; Yoshida, N.; Taniguchi, M.; Ezato, K.; Sato, K.; Suzuki, S.; Akiba, M.; Tsunekawa, Y.; Okumiya, M.

    2005-01-01

    To investigate the synergistic effects of heat load and hydrogen irradiation, cyclic heat load tests with a hydrogen beam and a comparable electron beam were performed for high purity CVD-tungsten coatings. Surface modification was examined as a function of the peak temperature by changing the heat flux. Scanning Electron Microscopy analysis showed that the surface damage caused by the hydrogen beam was more severe than that by the electron beam. In the hydrogen beam case, cracking at the surface occurred at all peak temperatures examined from 300 deg. C to 1600 deg. C. These results indicate that the injected hydrogen induces embrittlement for the CVD-tungsten coating

  3. Effect of Simulated High Hydrogen Content Combustion Environments on Abradable Properties of Ceramic Turbine Coatings

    Science.gov (United States)

    Basu Majumder, Madhura

    Air plasma sprayed (APS) abradable coatings are used in the turbine hot section to reduce the stator-rotor gap, minimizing gas leakage. These coatings are designed to exhibit controlled removal of material in thin layers when the turbine blades sweep through the coating, which protects the mechanical integrity of the turbine blade. In an effort to lower CO2 emissions, high H2 content fuel is being explored. This change in chemical composition of the fuel may affect the microstructure, abradability and durability of the coatings at turbine operational temperatures. The presence of high water vapor in the combustion chamber leads to accelerated degradation of the sacrificial coating materials. In this work, zirconia based composite materials with a machinable phase and varied porosity have been used to study microstructural evolution, thermal and chemical stability of the phases and abradable characteristics of baseline coating systems in both humid and dry environments. Investigation of the mechanisms that control the removal of materials and performance of abradable coatings through thermo-mechanical tests will be discussed.

  4. Influence of Starting Powders on Hydroxyapatite Coatings Fabricated by Room Temperature Spraying Method.

    Science.gov (United States)

    Seo, Dong Seok; Lee, Jong Kook; Hwang, Kyu Hong; Hahn, Byung Dong; Yoon, Seog Young

    2015-08-01

    Three types of raw materials were used for the fabrication of hydroxyapatite coatings by using the room temperature spraying method and their influence on the microstructure and in vitro characteristics were investigated. Starting hydroxyapatite powders for coatings on titanium substrate were prepared by a heat treatment at 1100 °C for 2 h of bovine bone, bone ash, and commercial hydroxyapatite powders. The phase compositions and Ca/P ratios of the three hydroxyapatite coatings were similar to those of the raw materials without decomposition or formation of a new phase. All hydroxyapatite coatings showed a honeycomb structure, but their surface microstructures revealed different features in regards to surface morphology and roughness, based on the staring materials. All coatings consisted of nano-sized grains and had dense microstructure. Inferred from in vitro experiments in pure water, all coatings have a good dissolution-resistance and biostability in water.

  5. Understanding the Role of Temperature and Cathode Composition on Interface and Bulk: Optimizing Aluminum Oxide Coatings for Li-Ion Cathodes

    International Nuclear Information System (INIS)

    Han, Binghong; Paulauskas, Tadas; Key, Baris; Peebles, Cameron; Park, Joong Sun

    2017-01-01

    Here, surface coating of cathode materials with Al_2O_3 has been shown to be a promising method for cathode stabilization and improved cycling performance at high operating voltages. However, a detailed understanding on how coating process and cathode composition changes the chemical composition, morphology and distribution of coating within cathode interface and bulk lattice, is still missing. In this study, we use a wet-chemical method to synthesize a series of Al_2O_3-coated LiNi_0_._5Co_0_._2Mn_0_._3O_2 and LiCoO_2 cathodes treated under various annealing temperatures and a combination of structural characterization techniques to understand the composition, homogeneity and morphology of coating layer and the bulk cathode. Nuclear magnetic resonance and electron microscopy results reveal that the nature of the interface is highly depended on the annealing temperature and cathode composition. For Al_2O_3-coated LiNi_0_._5Co_0_._2Mn_0_._3O_2, higher annealing temperature leads to more homogeneous and more closely attached coating on cathode materials, corresponding to better electrochemical performance. Lower Al_2O_3 coating content is found to be helpful to further improve the initial capacity and cyclability, which can greatly outperform the pristine cathode material. For Al_2O_3-coated LiCoO_2, the incorporation of Al into the cathode lattice is observed after annealing at high temperatures, implying the transformation from “surface coatings” to “dopants”, which is not observed for LiNi_0_._5Co_0_._2Mn_0_._3O_2. As a result, Al_2O_3-coated LiCoO_2 annealed at higher temperature shows similar initial capacity but lower retention compared to that annealed at a lower temperature, due to the intercalation of surface alumina into the bulk layered structure forming a solid solution.

  6. Room-temperature aqueous plasma electrolyzing Al2O3 nano-coating on carbon fiber

    Science.gov (United States)

    Zhang, Yuping; Meng, Yang; Shen, Yonghua; Chen, Weiwei; Cheng, Huanwu; Wang, Lu

    2017-10-01

    A novel room-temperature aqueous plasma electrolysis technique has been developed in order to prepared Al2O3 nano-coating on each fiber within a carbon fiber bundle. The microstructure and formation mechanism of the Al2O3 nano-coating were systematically investigated. The oxidation resistance and tensile strength of the Al2O3-coated carbon fiber was measured at elevated temperatures. It showed that the dense Al2O3 nano-coating was relatively uniformly deposited with 80-120 nm in thickness. The Al2O3 nano-coating effectively protected the carbon fiber, evidenced by the slower oxidation rate and significant increase of the burn-out temperature from 800 °C to 950 °C. Although the bare carbon fiber remained ∼25 wt.% after oxidation at 700 °C for 20 min, a full destruction was observed, evidenced by the ∼0 GPa of the tensile strength, compared to ∼1.3 GPa of the Al2O3-coated carbon fiber due to the effective protection from the Al2O3 nano-coating. The formation mechanism of the Al2O3 nano-coating on carbon fiber was schematically established mainly based on the physic-chemical effect in the cathodic plasma arc zone.

  7. Cavitation erosion of silver plated coating at different temperatures and pressures

    Energy Technology Data Exchange (ETDEWEB)

    Hattori, Shuji; Motoi, Yoshihiro [Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fuku-shi, Fukui 910-8507 (Japan); Kikuta, Kengo; Tomaru, Hiroshi [IHI Corperation, TOYOSU IHI BUILDING, 1-1, Toyosu 3-chome, Koto-ku, Tokyo 1358710 (Japan)

    2014-04-11

    Cavitation often occurs in inducer pumps used for space rockets. Silver plated coating on the inducer liner faces the damage of cavitation. Therefore, it is important to study about the cavitation erosion resistance for silver plated coating at several operating conditions in the inducer pumps. In this study, the cavitation erosion tests were carried for silver plated coating in deionized water and ethanol at several liquid temperatures (273K–400K) and pressures (0.10MPa–0.48MPa). The mass loss rate is evaluated in terms of thermodynamic parameter Σ proposed by Brennen [9], suppression pressure p–p{sub v} (p{sub v}: saturated vapor pressure) and acoustic impedance ρc (ρ: density and c: sound speed). Cavitation bubble behaviors depending on the thermodynamic effect and the liquid type were observed by high speed video camera. The mass loss rate is formulated by thermodynamic parameter Σ, suppression pressure p–p{sub v} and acoustic impedance ρc.

  8. High Temperature Transparent Furnace Development

    Science.gov (United States)

    Bates, Stephen C.

    1997-01-01

    This report describes the use of novel techniques for heat containment that could be used to build a high temperature transparent furnace. The primary objective of the work was to experimentally demonstrate transparent furnace operation at 1200 C. Secondary objectives were to understand furnace operation and furnace component specification to enable the design and construction of a low power prototype furnace for delivery to NASA in a follow-up project. The basic approach of the research was to couple high temperature component design with simple concept demonstration experiments that modify a commercially available transparent furnace rated at lower temperature. A detailed energy balance of the operating transparent furnace was performed, calculating heat losses through the furnace components as a result of conduction, radiation, and convection. The transparent furnace shells and furnace components were redesigned to permit furnace operation at at least 1200 C. Techniques were developed that are expected to lead to significantly improved heat containment compared with current transparent furnaces. The design of a thermal profile in a multizone high temperature transparent furnace design was also addressed. Experiments were performed to verify the energy balance analysis, to demonstrate some of the major furnace improvement techniques developed, and to demonstrate the overall feasibility of a high temperature transparent furnace. The important objective of the research was achieved: to demonstrate the feasibility of operating a transparent furnace at 1200 C.

  9. "Green" High-Temperature Polymers

    Science.gov (United States)

    Meador, Michael A.

    1998-01-01

    PMR-15 is a processable, high-temperature polymer developed at the NASA Lewis Research Center in the 1970's principally for aeropropulsion applications. Use of fiber-reinforced polymer matrix composites in these applications can lead to substantial weight savings, thereby leading to improved fuel economy, increased passenger and payload capacity, and better maneuverability. PMR-15 is used fairly extensively in military and commercial aircraft engines components seeing service temperatures as high as 500 F (260 C), such as the outer bypass duct for the F-404 engine. The current world-wide market for PMR-15 materials (resins, adhesives, and composites) is on the order of $6 to 10 million annually.

  10. High-temperature metallography setup

    International Nuclear Information System (INIS)

    Blumenfeld, M.; Shmarjahu, D.; Elfassy, S.

    1979-06-01

    A high-temperature metallography setup is presented. In this setup the observation of processes such as that of copper recrystallization was made possible, and the structure of metals such as uranium could be revealed. A brief historical review of part of the research works that have been done with the help of high temperature metallographical observation technique since the beginning of this century is included. Detailed description of metallographical specimen preparation technique and theoretical criteria based on the rate of evaporation of materials present on the polished surface of the specimens are given

  11. High temperature corrosion in gasifiers

    Directory of Open Access Journals (Sweden)

    Bakker Wate

    2004-01-01

    Full Text Available Several commercial scale coal gasification combined cycle power plants have been built and successfully operated during the last 5-10 years. Supporting research on materials of construction has been carried out for the last 20 years by EPRI and others. Emphasis was on metallic alloys for heat exchangers and other components in contact with hot corrosive gases at high temperatures. In this paper major high temperature corrosion mechanisms, materials performance in presently operating gasifiers and future research needs will be discussed.

  12. High temperature creep of vanadium

    International Nuclear Information System (INIS)

    Juhasz, A.; Kovacs, I.

    1978-01-01

    The creep behaviour of polycrystalline vanadium of 99.7% purity has been investigated in the temperature range 790-880 0 C in a high temperature microscope. It was found that the creep properties depend strongly on the history of the sample. To take this fact into account some additional properties such as the dependence of the yield stress and the microhardness on the pre-annealing treatment have also been studied. Samples used in creep measurements were selected on the basis of their microhardness. The activation energy of creep depends on the microhardness and on the creep temperature. In samples annealed at 1250 0 C for one hour (HV=160 kgf mm -2 ) the rate of creep is controlled by vacancy diffusion in the temperature range 820-880 0 C with an activation energy of 78+-8 kcal mol -1 . (Auth.)

  13. Development of high-index optical coating for security holograms

    Science.gov (United States)

    Ahmed, Nadir A. G.

    2000-10-01

    Over the past few years security holograms have grown into a complex business to prevent counterfeiting of security cards, banknotes and the like. Rapid advances in holographic technology have led to a growing requirement for optical materials and coating methods to produce such holograms at reasonable costs. These materials have specific refractive indices and are used to fabricate semi- transparent holograms. The present paper describes a coating process to deposit optical coating on flexible films inside a vacuum web metallizer for the production of high quality semi-transparent holograms.

  14. High Pressure and Temperature Effects in Polymers

    Science.gov (United States)

    Bucknall, David; Arrighi, Valeria; Johnston, Kim; Condie, Iain

    Elastomers are widely exploited as the basis for seals in gas and fluid pipelines. The underlying behaviour of these elastomer at the high pressure, elevated temperatures they experience in operation is poorly understood. Consequently, the duty cycle of these materials is often deliberately limited to a few hours, and in order to prevent failure, production is stopped in order to change the seals in critical joints. The result is significant time lost due to bringing down production to change the seals as well as knock on financial costs. In order to address the fundamental nature of the elastomers at their intended operating conditions, we are studying the gas permeation behaviour of hydrogenated natural butyl rubber (HNBR) and fluorinated elastomers (FKM) at a high pressure and elevated temperature. We have developed a pressure system that permits gas permeation studies at gas pressures of up to 5000 psi and operating temperatures up to 150° C. In this paper, we will discuss the nature of the permeation behaviour at these extreme operating conditions, and how this relates to the changes in the polymer structure. We will also discuss the use of graphene-polymer thin layer coatings to modify the gas permeation behaviour of the elastomers.

  15. Fibre Tip Sensors for Localised Temperature Sensing Based on Rare Earth-Doped Glass Coatings

    Directory of Open Access Journals (Sweden)

    Erik P. Schartner

    2014-11-01

    Full Text Available We report the development of a point temperature sensor, based on monitoring upconversion emission from erbium:ytterbium-doped tellurite coatings on the tips of optical fibres. The dip coating technique allows multiple sensors to be fabricated simultaneously, while confining the temperature-sensitive region to a localised region on the end-face of the fibre. The strong response of the rare earth ions to changing temperature allows a resolution of 0.1–0.3 °C to be recorded over the biologically relevant range of temperatures from 23–39 °C.

  16. High-temperature plasma physics

    International Nuclear Information System (INIS)

    Furth, H.P.

    1988-03-01

    Both magnetic and inertial confinement research are entering the plasma parameter range of fusion reactor interest. This paper reviews the individual and common technical problems of these two approaches to the generation of thermonuclear plasmas, and describes some related applications of high-temperature plasma physics

  17. High-Temperature Vibration Damper

    Science.gov (United States)

    Clarke, Alan; Litwin, Joel; Krauss, Harold

    1987-01-01

    Device for damping vibrations functions at temperatures up to 400 degrees F. Dampens vibrational torque loads as high as 1,000 lb-in. but compact enough to be part of helicopter rotor hub. Rotary damper absorbs energy from vibrating rod, dissipating it in turbulent motion of viscous hydraulic fluid forced by moving vanes through small orifices.

  18. Containment of high temperature plasmas

    International Nuclear Information System (INIS)

    Bass, R.W.; Ferguson, H.R.P.; Fletcher, H. Jr.; Gardner, J.; Harrison, B.K.; Larsen, K.M.

    1973-01-01

    Apparatus is described for confining a high temperature plasma which comprises: 1) envelope means shaped to form a toroidal hollow chamber containing a plasma, 2) magnetic field line generating means for confining the plasma in a smooth toroidal shape without cusps. (R.L.)

  19. Chemistry of high temperature superconductors

    CERN Document Server

    1991-01-01

    This review volume contains the most up-to-date articles on the chemical aspects of high temperature oxide superconductors. These articles are written by some of the leading scientists in the field and includes a comprehensive list of references. This is an essential volume for researchers working in the fields of ceramics, materials science and chemistry.

  20. Properties of high temperature SQUIDS

    International Nuclear Information System (INIS)

    Falco, C.M.; Wu, C.T.

    1978-01-01

    A review is given of the present status of weak links and dc and rf biased SQUIDs made with high temperature superconductors. A method for producing reliable, reproducible devices using Nb 3 Sn is outlined, and comments are made on directions future work should take

  1. High temperature component life assessment

    CERN Document Server

    Webster, G A

    1994-01-01

    The aim of this book is to investigate and explain the rapid advances in the characterization of high temperature crack growth behaviour which have been made in recent years, with reference to industrial applications. Complicated mathematics has been minimized with the emphasis placed instead on finding solutions using simplified procedures without the need for complex numerical analysis.

  2. Alfinated coating structure on HS6-5-2 (SW7M high speed steel

    Directory of Open Access Journals (Sweden)

    T. Szymczak

    2010-10-01

    Full Text Available The paper presents the results of immersion alfinated coating structure in AlSi5 silumin on HS6-5-2 (SW7M high speed steel. Alfinating bath temperature was 750 ± 5 ° C, time of sample immersion was τ = 180s. Thickness of obtained coating under specified conditions was g = 150μm. Manufactured coating consists of three layers of different construction phase. The first layer from the substrate „g1`” constructed with a AlFe phase consist of alloy additives constituents of HS6-5-2 (SW7M steel: W, Mo, V, Cr and Si. On it crystallizes the second layer „g1``” of AlFeWMoCr intermetallic phases also containing Si and small amount of V. Last, the outer layer „g2” of the coating is composed with silumin including AlFeWMoCrVSi intermetallic phases. Within all layers of the coating occurs carbides. Penetration of carbides to individual coating layers is mainly due to steel surface partial melting and crystallizing layers „g1`” and „g1``” by alfinating liquid and shifting into her of carbides as well as partial carbides rejection by crystallization front of intermetallic phases occurs in coating.

  3. Effects of deposition temperature on electrodeposition of zinc–nickel alloy coatings

    International Nuclear Information System (INIS)

    Qiao, Xiaoping; Li, Helin; Zhao, Wenzhen; Li, Dejun

    2013-01-01

    Highlights: ► Both normal and anomalous deposition can be realized by changing bath temperature. ► The Ni content in Zn–Ni alloy deposit increases sharply as temperature reach 60 °C. ► The abrupt change in coating composition is caused by the shift of cathodic potential. ► The deposition temperature has great effect on microstructure of Zn–Ni alloy deposit. -- Abstract: Zinc–nickel alloy coatings were electrodeposited on carbon steel substrates from the ammonium chloride bath at different temperatures. The composition, phase structure and morphology of these coatings were analyzed by energy dispersive spectrometer, X-ray diffractometer and scanning electron microscopy respectively. Chronopotentiometry and potentiostatic methods were also employed to analyze the possible causes of the composition and structure changes induced by deposition temperature. It has been shown that both normal and anomalous co-deposition of zinc and nickel could be realized by changing deposition temperature under galvanostatic conditions. The abrupt changes in the composition and phase structure of the zinc–nickel alloy coatings were observed when deposition temperature reached 60 °C. The sharply decrease of current efficiency for zinc–nickel co-deposition was also observed when deposition temperature is higher than 40 °C. Analysis of the partial current densities showed that the decrease of current efficiency with the rise of deposition temperature was due to the enhancement of the hydrogen evolution. It was also confirmed that the ennoblement of cathodic potential was the cause for the increase of nickel content in zinc–nickel alloy coatings as a result of deposition temperature rise. The good zinc–nickel alloy coatings with compact morphology and single γ phase could be obtained when the deposition temperature was fixed at 30–40 °C

  4. Ferrites based infrared radiation coatings with high emissivity and high thermal shock resistance and their application on energy-saving kettle

    International Nuclear Information System (INIS)

    Zhang, Jianyi; Fan, Xi’an; Lu, Lei; Hu, Xiaoming; Li, Guangqiang

    2015-01-01

    Highlights: • The ferrites based infrared radiation coating was prepared by HVOF for the first time. • The infrared radiation coatings were applied firstly on the household kettle. • The bonding strength between the coating and substrate could reach 30.7 MPa. • The coating kept intact when cycle reached 27 by quenching from 1000 °C using water. • The energy-saving efficiency of the kettle with coating could reach 30.5%. - Abstract: Starting from Fe 2 O 3 , MnO 2 , Co 2 O 3 and NiO powders, the ferrites based infrared radiation coatings with high emissivity and high thermal shock resistance were successfully prepared on the surface of carbon steel by high velocity oxy-fuel spraying (HVOF). The coating thickness was about 120–150 μm and presented a typical flat lamellar structure. The coating surface was rough and some submicron grade grains distributed on it. The infrared emissivity of the ferrites based coating by HVOF was over 0.74 in 3–20 μm waveband at 800 °C, which was obviously higher than that of the coating by brushing process in the short waveband. The bonding strength was 30.7 MPa between the coating and substrate, which was five times more than that of conventional coatings by brushing process. The combined effect of the superior bonding strength, typical lamellar structure, pre-existing microcracks and newly generated pores made the cycle times reach 27 when the coating samples were quenched from 1000 °C using water. Lastly, the infrared radiation coatings were applied on the underside of household kettle, and the energy-saving efficiency could reach 30.5%. The ferrites based infrared radiation coatings obtained in this work are good candidates for saving energy in the field of cookware and industrial high temperature furnace

  5. Conformal coating of amorphous silicon and germanium by high pressure chemical vapor deposition for photovoltaic fabrics

    Science.gov (United States)

    Ji, Xiaoyu; Cheng, Hiu Yan; Grede, Alex J.; Molina, Alex; Talreja, Disha; Mohney, Suzanne E.; Giebink, Noel C.; Badding, John V.; Gopalan, Venkatraman

    2018-04-01

    Conformally coating textured, high surface area substrates with high quality semiconductors is challenging. Here, we show that a high pressure chemical vapor deposition process can be employed to conformally coat the individual fibers of several types of flexible fabrics (cotton, carbon, steel) with electronically or optoelectronically active materials. The high pressure (˜30 MPa) significantly increases the deposition rate at low temperatures. As a result, it becomes possible to deposit technologically important hydrogenated amorphous silicon (a-Si:H) from silane by a simple and very practical pyrolysis process without the use of plasma, photochemical, hot-wire, or other forms of activation. By confining gas phase reactions in microscale reactors, we show that the formation of undesired particles is inhibited within the microscale spaces between the individual wires in the fabric structures. Such a conformal coating approach enables the direct fabrication of hydrogenated amorphous silicon-based Schottky junction devices on a stainless steel fabric functioning as a solar fabric.

  6. Heat suppression of the fiber coating on a cladding light stripper in high-power fiber laser.

    Science.gov (United States)

    Yan, Ming-Jian; Wang, Zheng; Meng, Ling-Qiang; Yin, Lu; Han, Zhi-Gang; Shen, Hua; Wang, Hai-Lin; Zhu, Ri-Hong

    2018-01-20

    We present a theoretical model for the thermal effect of the fiber coating on a high-power cladding light stripper, which is fabricated by chemical etching. For the input and output of the fiber coating, a novel segmented corrosion method and increasing attenuation method are proposed for heat suppression, respectively. The relationship between the attenuation and temperature rise of the fiber coating at the output is experimentally demonstrated. The temperature distribution of the fiber coating at the input as well as the return light power caused by scattering are measured for the etched fiber with different surface roughness values. The results suggest that the rise in temperature is primarily caused by the scattering light propagating into the coating. Finally, an attenuation of 27 dB is achieved. At a room temperature of 23°C and input pump power of 438 W, the highest temperature of the input fiber coating decreases from 39.5°C to 27.9°C by segmented corrosion, and the temperature rise of the output fiber coating is close to 0.

  7. Alternative waste form development: low-temperature pyrolytic-carbon coatings

    International Nuclear Information System (INIS)

    Oma, K.H.; Rusin, J.M.; Kidd, R.W.; Browning, M.F.

    1981-01-01

    Large simulted waste-forms can be coated with PyC in screw-agitated coater (SAC) at low temperatures. Higher coating rates are obtained using Ni(CO) 4 as a catalyst rather than Fe(CO) 5 or Co(AcAc) 2 ; coating quality and deposition rates are improved when C 2 H 2 is used as carbon-source gas rather than methane, propane, heptane and toluene; H 2 is a better carrier gas than Ar or N 2 . Improved coating quality and deposition rates are obtained with H 2 ; deposition rates increase with Ni(CO) 4 concentration, C 2 H 2 concentration and reaction temperature. Increasing the Ni(CO) 4 and C 2 H 2 concentrations reduces the quality of the coatings; however, better adhesion of the coating to the substrate is obtained as temperature is increased; highest quality catalyzed PyC coatings have been obtained using 0.001 and 0.01 mole % Ni(CO) 4 , 1.5 to 3.0 mole % C 2 H 2 , and the balance H 2 at 425 and 525 0 C; and deposition rates are higher in the fluidized bed coater than the SAC

  8. Effect of the deposition temperature on corrosion resistance and biocompatibility of the hydroxyapatite coatings

    Science.gov (United States)

    Vladescu, A.; Braic, M.; Azem, F. Ak; Titorencu, I.; Braic, V.; Pruna, V.; Kiss, A.; Parau, A. C.; Birlik, I.

    2015-11-01

    Hydroxyapatite (HAP) ceramics belong to a class of calcium phosphate-based materials, which have been widely used as coatings on titanium medical implants in order to improve bone fixation and thus to increase the lifetime of the implant. In this study, HAP coatings were deposited from pure HAP targets on Ti6Al4V substrates using the radio-frequency magnetron sputtering technique at substrate temperatures ranging from 400 to 800 °C. The surface morphology and the crystallographic structure of the films were investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The corrosion resistance of the coatings in saliva solution at 37 °C was evaluated by potentiodynamic polarization. Additionally, the human osteosarcoma cell line (MG-63) was used to test the biocompatibility of the coatings. The results showed that all of the coatings grown uniformly and that the increasing substrate temperature induced an increase in their crystallinity. Corrosion performance of the coatings was improved with the increase of the substrate temperature from 400 °C to 800 °C. Furthermore, all the coatings support the attachment and growth of the osteosarcoma cells with regard to the in vitro test findings.

  9. High temperature fusion reactor design

    International Nuclear Information System (INIS)

    Harkness, S.D.; dePaz, J.F.; Gohar, M.Y.; Stevens, H.C.

    1979-01-01

    Fusion energy may have unique advantages over other systems as a source for high temperature process heat. A conceptual design of a blanket for a 7 m tokamak reactor has been developed that is capable of producing 1100 0 C process heat at a pressure of approximately 10 atmospheres. The design is based on the use of a falling bed of MgO spheres as the high temperature heat transfer system. By preheating the spheres with energy taken from the low temperature tritium breeding part of the blanket, 1086 MW of energy can be generated at 1100 0 C from a system that produces 3000 MW of total energy while sustaining a tritium breeding ratio of 1.07. The tritium breeding is accomplished using Li 2 O modules both in front of (6 cm thick) and behind (50 cm thick) the high temperature ducts. Steam is used as the first wall and front tritium breeding module coolant while helium is used in the rear tritium breeding region. The system produces 600 MW of net electricity for use on the grid

  10. High Temperature, High Power Piezoelectric Composite Transducers

    Science.gov (United States)

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  11. Protection of 310l Stainless Steel from Wear at Elevated Temperatures using Conicraly Thermal Spray Coatings with and without Sic Addition

    Science.gov (United States)

    Zhang, Yan; Zhang, Tao; Li, Kaiyang; Li, Dongyang

    2017-10-01

    Due to its high oxidation resistance, 310L stainless steel is often used for thermal facilities working at high-temperatures. However, the steel may fail prematurely at elevated temperatures when encounter surface mechanical attacks such as wear. Thermal spray coatings have been demonstrated to be effective in protecting the steel from wear at elevated temperatures. In this study, we investigated the effectiveness of high velocity oxy-fuel(HVOF) spraying CoNiCrAlY/SiC coatings in resisting wear of 310L stainless steel at elevated temperature using a pin-on-disc wear tester. In order to further improve the performance of the coating, 5%SiC was added to the coating. It was demonstrated that the CoNiCrAlY/SiC coating after heat treatment markedly suppressed wear. However, the added SiC particles did not show benefits to the wear resistance of the coating. Microstructures of CoNiCrAlY coatings with and without the SiC addition were characterized in order to understand the mechanism responsible for the observed phenomena.

  12. Room-temperature solid phase ionic liquid (RTSPIL) coated Ω-transaminases: Development and application in organic solvents

    DEFF Research Database (Denmark)

    Grabner, B.; Nazario, M. A.; Gundersen, M. T.

    2018-01-01

    ω-Transaminases ATA-40, ATA-47 and ATA-82P were coated with room-temperature solid phase ionic liquids (RTSPILs) by means of three methods, melt coating, precipitation coating, and co‐lyophilization, and showed increased stability in all of the five tested organic solvents. Co‐lyophilization and ......ω-Transaminases ATA-40, ATA-47 and ATA-82P were coated with room-temperature solid phase ionic liquids (RTSPILs) by means of three methods, melt coating, precipitation coating, and co‐lyophilization, and showed increased stability in all of the five tested organic solvents. Co...

  13. Sintered tantalum carbide coatings on graphite substrates: Highly reliable protective coatings for bulk and epitaxial growth

    International Nuclear Information System (INIS)

    Nakamura, Daisuke; Suzumura, Akitoshi; Shigetoh, Keisuke

    2015-01-01

    Highly reliable low-cost protective coatings have been sought after for use in crucibles and susceptors for bulk and epitaxial film growth processes involving wide bandgap materials. Here, we propose a production technique for ultra-thick (50–200 μmt) tantalum carbide (TaC) protective coatings on graphite substrates, which consists of TaC slurry application and subsequent sintering processes, i.e., a wet ceramic process. Structural analysis of the sintered TaC layers indicated that they have a dense granular structure containing coarse grain with sizes of 10–50 μm. Furthermore, no cracks or pinholes penetrated through the layers, i.e., the TaC layers are highly reliable protective coatings. The analysis also indicated that no plastic deformation occurred during the production process, and the non-textured crystalline orientation of the TaC layers is the origin of their high reliability and durability. The TaC-coated graphite crucibles were tested in an aluminum nitride (AlN) sublimation growth process, which involves extremely corrosive conditions, and demonstrated their practical reliability and durability in the AlN growth process as a TaC-coated graphite. The application of the TaC-coated graphite materials to crucibles and susceptors for use in bulk AlN single crystal growth, bulk silicon carbide (SiC) single crystal growth, chemical vapor deposition of epitaxial SiC films, and metal-organic vapor phase epitaxy of group-III nitrides will lead to further improvements in crystal quality and reduced processing costs

  14. Sintered tantalum carbide coatings on graphite substrates: Highly reliable protective coatings for bulk and epitaxial growth

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Daisuke; Suzumura, Akitoshi; Shigetoh, Keisuke [Toyota Central R and D Labs., Inc., Nagakute, Aichi 480-1192 (Japan)

    2015-02-23

    Highly reliable low-cost protective coatings have been sought after for use in crucibles and susceptors for bulk and epitaxial film growth processes involving wide bandgap materials. Here, we propose a production technique for ultra-thick (50–200 μmt) tantalum carbide (TaC) protective coatings on graphite substrates, which consists of TaC slurry application and subsequent sintering processes, i.e., a wet ceramic process. Structural analysis of the sintered TaC layers indicated that they have a dense granular structure containing coarse grain with sizes of 10–50 μm. Furthermore, no cracks or pinholes penetrated through the layers, i.e., the TaC layers are highly reliable protective coatings. The analysis also indicated that no plastic deformation occurred during the production process, and the non-textured crystalline orientation of the TaC layers is the origin of their high reliability and durability. The TaC-coated graphite crucibles were tested in an aluminum nitride (AlN) sublimation growth process, which involves extremely corrosive conditions, and demonstrated their practical reliability and durability in the AlN growth process as a TaC-coated graphite. The application of the TaC-coated graphite materials to crucibles and susceptors for use in bulk AlN single crystal growth, bulk silicon carbide (SiC) single crystal growth, chemical vapor deposition of epitaxial SiC films, and metal-organic vapor phase epitaxy of group-III nitrides will lead to further improvements in crystal quality and reduced processing costs.

  15. Summary: High Temperature Downhole Motor

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, David W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-10-01

    Directional drilling can be used to enable multi-lateral completions from a single well pad to improve well productivity and decrease environmental impact. Downhole rotation is typically developed with a motor in the Bottom Hole Assembly (BHA) that develops drilling power (speed and torque) necessary to drive rock reduction mechanisms (i.e., the bit) apart from the rotation developed by the surface rig. Historically, wellbore deviation has been introduced by a “bent-sub,” located in the BHA, that introduces a small angular deviation, typically less than 3 degrees, to allow the bit to drill off-axis with orientation of the BHA controlled at the surface. The development of a high temperature downhole motor would allow reliable use of bent subs for geothermal directional drilling. Sandia National Laboratories is pursuing the development of a high temperature motor that will operate on either drilling fluid (water-based mud) or compressed air to enable drilling high temperature, high strength, fractured rock. The project consists of designing a power section based upon geothermal drilling requirements; modeling and analysis of potential solutions; and design, development and testing of prototype hardware to validate the concept. Drilling costs contribute substantially to geothermal electricity production costs. The present development will result in more reliable access to deep, hot geothermal resources and allow preferential wellbore trajectories to be achieved. This will enable development of geothermal wells with multi-lateral completions resulting in improved geothermal resource recovery, decreased environmental impact and enhanced well construction economics.

  16. NSTX High Temperature Sensor Systems

    International Nuclear Information System (INIS)

    McCormack, B.; Kugel, H.W.; Goranson, P.; Kaita, R.

    1999-01-01

    The design of the more than 300 in-vessel sensor systems for the National Spherical Torus Experiment (NSTX) has encountered several challenging fusion reactor diagnostic issues involving high temperatures and space constraints. This has resulted in unique miniature, high temperature in-vessel sensor systems mounted in small spaces behind plasma facing armor tiles, and they are prototypical of possible high power reactor first-wall applications. In the Center Stack, Divertor, Passive Plate, and vessel wall regions, the small magnetic sensors, large magnetic sensors, flux loops, Rogowski Coils, thermocouples, and Langmuir Probes are qualified for 600 degrees C operation. This rating will accommodate both peak rear-face graphite tile temperatures during operations and the 350 degrees C bake-out conditions. Similar sensor systems including flux loops, on other vacuum vessel regions are qualified for 350 degrees C operation. Cabling from the sensors embedded in the graphite tiles follows narrow routes to exit the vessel. The detailed sensor design and installation methods of these diagnostic systems developed for high-powered ST operation are discussed

  17. Development of high temperature turbine

    Energy Technology Data Exchange (ETDEWEB)

    Takahara, Kitao; Nouse, Hiroyuki; Yoshida, Toyoaki; Minoda, Mitsuhiro; Matsusue, Katsutoshi; Yanagi, Ryoji

    1988-07-01

    For the contribution to the development of FJR710, high by-pass ratio turbofan engine, with the study for many years of the development of high efficiency turbine for the jet engine, the first technical prize from the Energy Resource Research Committee was awarded in April, 1988. This report introduced its technical contents. In order to improve the thermal efficiency and enlarge the output, it is very effective to raise the gas temperature at the inlet of gas turbine. For its purpose, by cooling the nozzle and moving blades and having those blades operate at lower temperature than that of the working limitation, they realized, for the first time in Japan, the technique of cooling turbine to heighten the operational gas temperature. By that technique, it was enabled to raise the gas temperature at the inlet of turbine, to 1,350/sup 0/C from 850/sup 0/C. This report explain many important points of study covering the basic test, visualizing flow experiment, material discussion and structural design in the process of development. (9 figs)

  18. The effects of zinc bath temperature on the coating growth behavior of reactive steel

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jianhua, E-mail: super_wang111@hotmail.com [School of Mechanical Engineering, Xiangtan University, Xiangtan, 411105 (China); Key Laboratory of Materials Design and Preparation Technology of Hunan Province, Xiangtan University, Xiangtan, 411105 (China); Tu Hao; Peng Bicao; Wang Xinming; Yin, Fucheng [School of Mechanical Engineering, Xiangtan University, Xiangtan, 411105 (China); Key Laboratory of Materials Design and Preparation Technology of Hunan Province, Xiangtan University, Xiangtan, 411105 (China); Su Xuping, E-mail: xuping@xtu.edu.cn [School of Mechanical Engineering, Xiangtan University, Xiangtan, 411105 (China); Key Laboratory of Materials Design and Preparation Technology of Hunan Province, Xiangtan University, Xiangtan, 411105 (China)

    2009-11-15

    The purpose of this work is to identify the influence of zinc bath temperature on the morphology and the thickness of reactive steel (Fe-0.1 wt.%Si alloy) coatings. The Fe-0.1 wt.%Si samples were galvanized for 3 min at temperatures in the range of 450-530 deg. C in steps of 10 deg. C. The coatings were characterized by using scanning electron microscopy/energy dispersive X-rays analysis. It was found that the coating thickness reaches the maximum at 470 deg. C and the minimum at 500 deg. C, respectively. When the reactive steel is galvanized at temperatures in the range of 450-490 deg. C, the coatings have a loose {zeta} layer on the top of a compact {delta} layer. With the increase of the galvanizing temperature, the {zeta} layer becomes looser. When the temperature is at 500 deg. C, the {zeta} phase disappears. With the increase of temperature, the coatings change to be a diffuse-{Delta} layer ({delta}+ liquid zinc).

  19. High temperature structural sandwich panels

    Science.gov (United States)

    Papakonstantinou, Christos G.

    High strength composites are being used for making lightweight structural panels that are being employed in aerospace, naval and automotive structures. Recently, there is renewed interest in use of these panels. The major problem of most commercial available sandwich panels is the fire resistance. A recently developed inorganic matrix is investigated for use in cases where fire and high temperature resistance are necessary. The focus of this dissertation is the development of a fireproof composite structural system. Sandwich panels made with polysialate matrices have an excellent potential for use in applications where exposure to high temperatures or fire is a concern. Commercial available sandwich panels will soften and lose nearly all of their compressive strength temperatures lower than 400°C. This dissertation consists of the state of the art, the experimental investigation and the analytical modeling. The state of the art covers the performance of existing high temperature composites, sandwich panels and reinforced concrete beams strengthened with Fiber Reinforced Polymers (FRP). The experimental part consists of four major components: (i) Development of a fireproof syntactic foam with maximum specific strength, (ii) Development of a lightweight syntactic foam based on polystyrene spheres, (iii) Development of the composite system for the skins. The variables are the skin thickness, modulus of elasticity of skin and high temperature resistance, and (iv) Experimental evaluation of the flexural behavior of sandwich panels. Analytical modeling consists of a model for the flexural behavior of lightweight sandwich panels, and a model for deflection calculations of reinforced concrete beams strengthened with FRP subjected to fatigue loading. The experimental and analytical results show that sandwich panels made with polysialate matrices and ceramic spheres do not lose their load bearing capability during severe fire exposure, where temperatures reach several

  20. Antimicrobial brass coatings prepared on poly(ethylene terephthalate) textile by high power impulse magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ying-Hung, E-mail: tieamo2002@gmail.com; Wu, Guo-Wei; He, Ju-Liang

    2015-03-01

    The goal of this work is to prepare antimicrobial, corrosion-resistant and low-cost Cu65Zn35 brass film on poly(ethylene terephthalate) (PET) fabric by high-power impulse magnetron sputtering (HIPIMS), which is known to provide high-density plasma, so as to generate a strongly adherent film at a reduced substrate temperature. The results reveal that the brass film grows in a layer-plus-island mode. Independent of their deposition time, the obtained films retain a Cu/Zn elemental composition ratio of 1.86 and exhibit primarily an α copper phase structure. Oxygen plasma pre-treatment for 1 min before coating can significantly increase film adhesion such that the brass-coated fabric of Grade 5 or Grade 4–5 can ultimately be obtained under dry and wet rubbing tests, respectively. However, a deposition time of 1 min suffices to provide effective antimicrobial properties for both Staphylococcus aureus and Escherichia coli. As a whole, the feasibility of using such advanced HIPIMS coating technique to develop durable antimicrobial textile was demonstrated. - Highlights: • Prepare antimicrobial, corrosion-resistant and low-cost Cu65Zn35 brass film on PET fabric by HIPIMS • Brass-coated fabric with excellent durability, even undergone rubbing and washing tests • Brass-coated fabric provides effective antimicrobial properties for E. coli and S. aureus. • After brass coating, PET fabric still retained its mechanical property.

  1. Antimicrobial brass coatings prepared on poly(ethylene terephthalate) textile by high power impulse magnetron sputtering

    International Nuclear Information System (INIS)

    Chen, Ying-Hung; Wu, Guo-Wei; He, Ju-Liang

    2015-01-01

    The goal of this work is to prepare antimicrobial, corrosion-resistant and low-cost Cu65Zn35 brass film on poly(ethylene terephthalate) (PET) fabric by high-power impulse magnetron sputtering (HIPIMS), which is known to provide high-density plasma, so as to generate a strongly adherent film at a reduced substrate temperature. The results reveal that the brass film grows in a layer-plus-island mode. Independent of their deposition time, the obtained films retain a Cu/Zn elemental composition ratio of 1.86 and exhibit primarily an α copper phase structure. Oxygen plasma pre-treatment for 1 min before coating can significantly increase film adhesion such that the brass-coated fabric of Grade 5 or Grade 4–5 can ultimately be obtained under dry and wet rubbing tests, respectively. However, a deposition time of 1 min suffices to provide effective antimicrobial properties for both Staphylococcus aureus and Escherichia coli. As a whole, the feasibility of using such advanced HIPIMS coating technique to develop durable antimicrobial textile was demonstrated. - Highlights: • Prepare antimicrobial, corrosion-resistant and low-cost Cu65Zn35 brass film on PET fabric by HIPIMS • Brass-coated fabric with excellent durability, even undergone rubbing and washing tests • Brass-coated fabric provides effective antimicrobial properties for E. coli and S. aureus. • After brass coating, PET fabric still retained its mechanical property

  2. Nanoscale coatings for erosion and corrosion protection of copper microchannel coolers for high powered laser diodes

    Science.gov (United States)

    Flannery, Matthew; Fan, Angie; Desai, Tapan G.

    2014-03-01

    High powered laser diodes are used in a wide variety of applications ranging from telecommunications to industrial applications. Copper microchannel coolers (MCCs) utilizing high velocity, de-ionized water coolant are used to maintain diode temperatures in the recommended range to produce stable optical power output and control output wavelength. However, aggressive erosion and corrosion attack from the coolant limits the lifetime of the cooler to only 6 months of operation. Currently, gold plating is the industry standard for corrosion and erosion protection in MCCs. However, this technique cannot perform a pin-hole free coating and furthermore cannot uniformly cover the complex geometries of current MCCs involving small diameter primary and secondary channels. Advanced Cooling Technologies, Inc., presents a corrosion and erosion resistant coating (ANCERTM) applied by a vapor phase deposition process for enhanced protection of MCCs. To optimize the coating formation and thickness, coated copper samples were tested in 0.125% NaCl solution and high purity de-ionized (DIW) flow loop. The effects of DIW flow rates and qualities on erosion and corrosion of the ANCERTM coated samples were evaluated in long-term erosion and corrosion testing. The robustness of the coating was also evaluated in thermal cycles between 30°C - 75°C. After 1000 hours flow testing and 30 thermal cycles, the ANCERTM coated copper MCCs showed a corrosion rate 100 times lower than the gold plated ones and furthermore were barely affected by flow rates or temperatures thus demonstrating superior corrosion and erosion protection and long term reliability.

  3. Ceramics for high temperature applications

    International Nuclear Information System (INIS)

    Mocellin, A.

    1977-01-01

    Problems related to materials, their fabrication, properties, handling, improvements are examined. Silicium nitride and silicium carbide are obtained by vacuum hot-pressing, reaction sintering and chemical vapour deposition. Micrographs are shown. Mechanical properties i.e. room and high temperature strength, creep resistance fracture mechanics and fatigue resistance. Recent developments of pressureless sintered Si C and the Si-Al-O-N quaternary system are mentioned

  4. High-temperature geothermal cableheads

    Science.gov (United States)

    Coquat, J. A.; Eifert, R. W.

    1981-11-01

    Two high temperature, corrosion resistant logging cable heads which use metal seals and a stable fluid to achieve proper electrical terminations and cable sonde interfacings are described. A tensile bar provides a calibrated yield point, and a cone assembly anchors the cable armor to the head. Electrical problems of the sort generally ascribable to the cable sonde interface were absent during demonstration hostile environment loggings in which these cable heads were used.

  5. Development of Advanced Environmental Barrier Coatings for SiC/SiC Ceramic Matrix Composites: Path Toward 2700 F Temperature Capability and Beyond

    Science.gov (United States)

    Zhu, Dongming; Harder, Bryan; Hurst, Janet B.; Good, Brian; Costa, Gustavo; Bhatt, Ramakrishna T.; Fox, Dennis S.

    2017-01-01

    Advanced environmental barrier coating systems for SiC-SiC Ceramic Matrix Composite (CMC) turbine and combustor hot section components are currently being developed to meet future turbine engine emission and performance goals. One of the significant coating development challenges is to achieve prime-reliant environmental barrier coating systems to meet the future 2700F EBC-CMC temperature stability and environmental durability requirements. This presentation will emphasize recent NASA environmental barrier coating system testing and down-selects, particularly the development path and properties towards 2700-3000F durability goals by using NASA hafnium-hafnia-rare earth-silicon-silicate composition EBC systems for the SiC-SiC CMC turbine component applications. Advanced hafnium-based compositions for enabling next generation EBC and CMCs capabilities towards ultra-high temperature ceramic coating systems will also be briefly mentioned.

  6. Enhancing the oxidation resistance of graphite by applying an SiC coat with crack healing at an elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae-Won, E-mail: pjw@kaeri.re.kr [Korea Atomic Energy Research Institute, 1045 Daedeok-Daero, Yuseong-Gu, Daejeon-City (Korea, Republic of); Kim, Eung-Seon; Kim, Jae-Un [Korea Atomic Energy Research Institute, 1045 Daedeok-Daero, Yuseong-Gu, Daejeon-City (Korea, Republic of); Kim, Yootaek [Dept. of Materials Engineering, Kyonggi Universtiy, Suwon (Korea, Republic of); Windes, William E. [Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

    2016-08-15

    Highlights: • Ion beam mixed SiC coating was performed on the graphite for the enhanced adhesion. • The SiC coated was cracked at the elevated temperature, confirming the strong bonding, and then was vigorously oxidized leaving only the SiC layer. • For crack healing, CVD crack healing increased by ∼4 times in 20% weight reduction in air at 900 °C as compared to PVD crack healing. - Abstract: The potential of reducing the oxidation of the supporting graphite components during normal and/or accident conditions in the Very High Temperature Reactor (VHTR) design has been studied. In this work efforts have been made to slow the oxidation process of the graphite with a thin SiC coating (∼ 10 μm). Upon heating at ≥ 1173 K in air, the spallations and cracks were formed in the dense columnar structured SiC coating layer grown on the graphite with a functionally gradient electron beam physical vapor deposition (EB-PVD. In accordance with the formations of these defects, the sample was vigorously oxidized, leaving only the SiC coating layer. Then, efforts were made to heal the surface defects using additional EB-PVD with ion beam bombardment and chemical vapor deposition (CVD). The EB-PVD did not effectively heal the cracks. But, the CVD was more appropriate for crack healing, likely due to its excellent crack line filling capability with a high density and high aspect ratio. It took ∼ 34 min for the 20% weight loss of the CVD crack healed sample in the oxidation test with annealing at 1173 K, while it took ∼ 8 min for the EB-PVD coated sample, which means it took ∼4 times longer at 1173 K for the same weight reduction in this experimental set-up.

  7. Enhancing the oxidation resistance of graphite by applying an SiC coat with crack healing at an elevated temperature

    International Nuclear Information System (INIS)

    Park, Jae-Won; Kim, Eung-Seon; Kim, Jae-Un; Kim, Yootaek; Windes, William E.

    2016-01-01

    Highlights: • Ion beam mixed SiC coating was performed on the graphite for the enhanced adhesion. • The SiC coated was cracked at the elevated temperature, confirming the strong bonding, and then was vigorously oxidized leaving only the SiC layer. • For crack healing, CVD crack healing increased by ∼4 times in 20% weight reduction in air at 900 °C as compared to PVD crack healing. - Abstract: The potential of reducing the oxidation of the supporting graphite components during normal and/or accident conditions in the Very High Temperature Reactor (VHTR) design has been studied. In this work efforts have been made to slow the oxidation process of the graphite with a thin SiC coating (∼ 10 μm). Upon heating at ≥ 1173 K in air, the spallations and cracks were formed in the dense columnar structured SiC coating layer grown on the graphite with a functionally gradient electron beam physical vapor deposition (EB-PVD. In accordance with the formations of these defects, the sample was vigorously oxidized, leaving only the SiC coating layer. Then, efforts were made to heal the surface defects using additional EB-PVD with ion beam bombardment and chemical vapor deposition (CVD). The EB-PVD did not effectively heal the cracks. But, the CVD was more appropriate for crack healing, likely due to its excellent crack line filling capability with a high density and high aspect ratio. It took ∼ 34 min for the 20% weight loss of the CVD crack healed sample in the oxidation test with annealing at 1173 K, while it took ∼ 8 min for the EB-PVD coated sample, which means it took ∼4 times longer at 1173 K for the same weight reduction in this experimental set-up.

  8. Fuel particle coating data

    International Nuclear Information System (INIS)

    Hollabaugh, C.M.; Wagner, P.; Wahman, L.A.; White, R.W.

    1977-01-01

    Development of coating on nuclear fuel particles for the High-Temperature Fuels Technology program at the Los Alamos Scientific Laboratory included process studies for low-density porous and high-density isotropic carbon coats, and for ZrC and ''alloy'' C/ZrC coats. This report documents the data generated by these studies

  9. Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings

    Science.gov (United States)

    Pechersky, Martin J.

    1999-01-01

    An improved method for measuring residual stress in a material comprising the steps of applying a spot of temperature indicating coating to the surface to be studied, establishing a speckle pattern surrounds the spot of coating with a first laser then heating the spot of coating with a far infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress during heating and enables calculation of the stress.

  10. Simple roll coater with variable coating and temperature control for printed polymer solar cells

    DEFF Research Database (Denmark)

    Dam, Henrik Friis; Krebs, Frederik C

    2012-01-01

    of solution, enabling roll coating testing of new polymers where only small amounts are often available. We demonstrate the formation of >50 solar cells (each with an active area of 1 cm2) with printed metal back electrodes using as little as 0.1 mL of active layer solution. This approach outperforms spin...... coating with respect to temperature control, ink usage, speed and is directly compatible with industrial processing and upscaling....

  11. The influence of annealing temperature on the strength of TRISO coated particles

    Energy Technology Data Exchange (ETDEWEB)

    Rooyen, I.J. van, E-mail: Isabel.vanrooyen@pbmr.co.z [Pebble Bed Modular Reactor (Pty) Ltd., 1279 Mike Crawford Avenue, Centurion (South Africa); Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Neethling, J.H. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Rooyen, P.M. van [Pebble Bed Modular Reactor (Pty) Ltd., 1279 Mike Crawford Avenue, Centurion (South Africa)

    2010-07-31

    The integrity of the Pebble Bed Modular Reactor (PBMR) fuel, and specifically the SiC layer system of the Tristructural Isotropic (TRISO) coated particle (CP), namely inner pyrolytic carbon, silicon carbide and outer pyrolytic carbon (I-PyC-SiC-O-PyC), determines the containment of fission products. The PBMR fuel consists of TRISO coated particles (CPs) embedded in a graphite matrix. One of the characterization techniques investigated by PBMR is the determination of strength of CPs. It is a well known metallurgical fact that temperature, amongst many other parameters, may influence the strength of a material. A recently developed method for measuring the strength of the TRISO coated particles was used and is briefly described in this article. The advantages of this method are demonstrated by the comparison of strength measurements of five experimental PBMR CP batches as a function of annealing temperature. Significant modification of strength after annealing was measured with increased temperature within the range 1000-2100 {sup o}C. The interesting feature of decreasing standard deviation of the strength with increasing temperature will also be discussed with a possible explanation. A significant difference in coated particle strength is also demonstrated for two CP batches with layer thickness on the extremities of the SiC layer thickness specification. The effect of long duration annealing on these strength values will also be demonstrated by comparing results from 1 h to 100 h annealing periods of coated particles at a temperature of 1600 {sup o}C.

  12. The influence of annealing temperature on the strength of TRISO coated particles

    International Nuclear Information System (INIS)

    Rooyen, I.J. van; Neethling, J.H.; Rooyen, P.M. van

    2010-01-01

    The integrity of the Pebble Bed Modular Reactor (PBMR) fuel, and specifically the SiC layer system of the Tristructural Isotropic (TRISO) coated particle (CP), namely inner pyrolytic carbon, silicon carbide and outer pyrolytic carbon (I-PyC-SiC-O-PyC), determines the containment of fission products. The PBMR fuel consists of TRISO coated particles (CPs) embedded in a graphite matrix. One of the characterization techniques investigated by PBMR is the determination of strength of CPs. It is a well known metallurgical fact that temperature, amongst many other parameters, may influence the strength of a material. A recently developed method for measuring the strength of the TRISO coated particles was used and is briefly described in this article. The advantages of this method are demonstrated by the comparison of strength measurements of five experimental PBMR CP batches as a function of annealing temperature. Significant modification of strength after annealing was measured with increased temperature within the range 1000-2100 o C. The interesting feature of decreasing standard deviation of the strength with increasing temperature will also be discussed with a possible explanation. A significant difference in coated particle strength is also demonstrated for two CP batches with layer thickness on the extremities of the SiC layer thickness specification. The effect of long duration annealing on these strength values will also be demonstrated by comparing results from 1 h to 100 h annealing periods of coated particles at a temperature of 1600 o C.

  13. Low Temperature Curing of Hydrogen Silsesquioxane Surface Coatings for Corrosion Protection of Aluminum

    DEFF Research Database (Denmark)

    Lampert, Felix; Jensen, Annemette Hindhede; Møller, Per

    2016-01-01

    Hydrogen Silsesquioxane (HSQ) has shown to be a promising precursor for corrosion protective glass coatings for metallic substrates due to the excellent barrier properties of the films, especially in the application of protective coatings for aluminum in the automotive industry where high chemica...

  14. Anti-biofilm efficacy of low temperature processed AgCl–TiO{sub 2} nanocomposite coating

    Energy Technology Data Exchange (ETDEWEB)

    Naik, Kshipra, E-mail: kshipra_naik21@yahoo.co.in; Kowshik, Meenal, E-mail: meenal@goa.bits-pilani.ac.in

    2014-01-01

    Biofilms are a major concern in the medical settings and food industries due to their high tolerance to antibiotics, biocides and mechanical stress. Currently, the development of novel methods to control biofilm formation is being actively pursued. In the present study, sol–gel coatings of AgCl–TiO{sub 2} nanoparticles are presented as potential anti-biofilm agents, wherein TiO{sub 2} acts as a good supporting matrix to prevent aggregation of silver and facilitates its controlled release. Low-temperature processed AgCl–TiO{sub 2} nanocomposite coatings inhibit biofilm formation by Escherichia coli, Staphylococcus epidermidis and Pseudomonas aeruginosa. In vitro biofilm assay experiments demonstrated that AgCl–TiO{sub 2} nanocomposite coated surfaces, inhibited the development of biofilms over a period of 10 days as confirmed by scanning electron microscopy. The silver release kinetics exhibited an initial high release, followed by a slow and sustained release. The anti-biofilm efficacy of the coatings could be attributed to the release of silver, which prevents the initial bacterial adhesion required for biofilm formation. - Highlights: • Potential of AgCl–TiO{sub 2} nanocomposite coating to inhibit biofilm formation is exhibited. • Initial rapid release followed by later slow and sustained release of silver obtained. • TiO{sub 2} being porous and inorganic in nature acts as a good supporting matrix.

  15. Effects of sintering temperature on the corrosion behavior of AZ31 alloy with Ca–P sol–gel coating

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Bo [School of Materials Science and Engineering, Liaoning University of Technology, Jinzhou, Liaoning Province, 121001 (China); Shi, Ping, E-mail: p_shi@sohu.com [School of Materials Science and Engineering, Liaoning University of Technology, Jinzhou, Liaoning Province, 121001 (China); Wei, Donghua [School of Materials Science and Engineering, Liaoning University of Technology, Jinzhou, Liaoning Province, 121001 (China); E, Shanshan [School of Mathematics and Physics, Bohai University, Jinzhou, Liaoning Province, 121013 (China); Li, Qiang; Chen, Yang [School of Materials Science and Engineering, Liaoning University of Technology, Jinzhou, Liaoning Province, 121001 (China)

    2016-04-25

    To slow down the initial biodegradation rate of magnesium alloy, calcium phosphate (Ca–P) coatings were prepared on AZ31 magnesium alloy by a sol–gel technique. To study the effects of sintering temperature on microstructure, bonding strength and corrosion behavior of the coatings, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and an adhesive strength test were used to characterize the coatings. The corrosion resistance of the coatings was investigated by immersion test and electrochemical corrosion techniques in simulated body fluid (SBF) solution. It shows that the sol–gel coatings consist of Ca{sub 2}P{sub 2}O{sub 7}, mixture of Ca{sub 2}P{sub 2}O{sub 7}, Ca{sub 3}(PO{sub 4}){sub 2} and hydroxyapatite, and hydroxyapatite, by sintering respectively at 300 °C, 400 °C and 500 °C. There are major cracks on the coatings. The crack area portion on the coating and the bonding strength at the interface between the calcium phosphate coating and the bare AZ31 increases, and the corrosion resistance of the coated AZ31 in SBF decreases with increasing sintering temperatures from 300 °C to 500 °C. Based on our investigations, the corrosion resistance of the coated AZ31 in SBF depends mainly on the crack area portion on the coatings, rather than on the coating phase stability. - Highlights: • Ca–P coating was prepared on AZ31 alloy by a sol–gel technique. • Crack area portion in the coating increases with temperatures. • Bonding strength between Ca–P coating and substrate increases with temperatures. • Corrosion resistance of the coated AZ31 in SBF decreases with temperatures. • Corrosion resistance of the coated AZ31 depends mainly on the crack area portion.

  16. Isothermal oxidation behaviour of thermal barrier coatings with CoCrAlY bond coat irradiated by high-current pulsed electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Jie [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Guan, Qingfeng, E-mail: guanqf@mail.ujs.edu.cn [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Hou, Xiuli [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Wang, Zhiping; Su, Jingxin; Han, Zhiyong [College of Science, Civil Aviation University of China, Tianjin 300300 (China)

    2014-10-30

    Highlights: • The original coarse surface was re-melted by pulsed electron beam irradiation. • Very fine grains were homogeneously dispersed on the irradiated coat surface. • A compact Al{sub 2}O{sub 3} scale was formed in irradiated TBCs at the onset of oxidation. • The selective oxidation of Al element avoided the formation of other oxides. • The irradiated coating has a much higher oxidation resistance. - Abstract: Thermal sprayed CoCrAlY bond coat irradiated by high-current pulsed electron beam (HCPEB) and thermal barrier coatings (TBCs) prepared with the irradiated bond coat and the ceramic top coat were investigated. The high temperature oxidation resistance of these specimens was tested at 1050 °C in air. Microstructure observations revealed that the original coarse surface of the as-sprayed bond coat was significantly changed as the interconnected bulged nodules with a compact appearance after HCPEB irradiation. Abundant Y-rich alumina particulates and very fine grains were dispersed on the irradiated surface. After high temperature oxidation test, the thermally grown oxide (TGO) in the initial TBCs grew rapidly and was comprised of two distinct layers: a large percentage of mixed oxides in the outer layer and a relatively small portion of Al{sub 2}O{sub 3} in the inner layer. Severe local internal oxidation and extensive cracks in the TGO layer were discovered as well. Comparatively, the irradiated TBCs exhibited thinner TGO layer, slower TGO growth rate, and homogeneous TGO composition (primarily consisting of Al{sub 2}O{sub 3}). The results indicate that TBCs with the irradiated bond coat have a much higher oxidation resistance.

  17. High temperature PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jianlu; Xie, Zhong; Zhang, Jiujun; Tang, Yanghua; Song, Chaojie; Navessin, Titichai; Shi, Zhiqing; Song, Datong; Wang, Haijiang; Wilkinson, David P.; Liu, Zhong-Sheng; Holdcroft, Steven [Institute for Fuel Cell Innovation, National Research Council Canada, Vancouver, BC (Canada V6T 1W5)

    2006-10-06

    There are several compelling technological and commercial reasons for operating H{sub 2}/air PEM fuel cells at temperatures above 100{sup o}C. Rates of electrochemical kinetics are enhanced, water management and cooling is simplified, useful waste heat can be recovered, and lower quality reformed hydrogen may be used as the fuel. This review paper provides a concise review of high temperature PEM fuel cells (HT-PEMFCs) from the perspective of HT-specific materials, designs, and testing/diagnostics. The review describes the motivation for HT-PEMFC development, the technology gaps, and recent advances. HT-membrane development accounts for {approx}90% of the published research in the field of HT-PEMFCs. Despite this, the status of membrane development for high temperature/low humidity operation is less than satisfactory. A weakness in the development of HT-PEMFC technology is the deficiency in HT-specific fuel cell architectures, test station designs, and testing protocols, and an understanding of the underlying fundamental principles behind these areas. The development of HT-specific PEMFC designs is of key importance that may help mitigate issues of membrane dehydration and MEA degradation. (author)

  18. 4TH International Conference on High-Temperature Ceramic Matrix Composites

    National Research Council Canada - National Science Library

    2001-01-01

    .... Topic to be covered include fibers, interfaces, interphases, non-oxide ceramic matrix composites, oxide/oxide ceramic matrix composites, coatings, and applications of high-temperature ceramic matrix...

  19. Comparative study of the interface composition of TiN and TiCN hard coatings on high speed steel substrates obtained by arc discharge

    Energy Technology Data Exchange (ETDEWEB)

    Roman, E. (Lab. de Fisica de Superficies, Inst. de Ciencia de Materiales, CSIC, Madrid (Spain)); Segovia, J.L. de (Lab. de Fisica de Superficies, Inst. de Ciencia de Materiales, CSIC, Madrid (Spain)); Alberdi, A. (TEKNIKER, Asociacion de Investigacion Tecnologica, Eibar (Spain)); Calvo, J. (TEKNIKER, Asociacion de Investigacion Tecnologica, Eibar (Spain)); Laucirica, J. (TEKNIKER, Asociacion de Investigacion Tecnologica, Eibar (Spain))

    1993-05-15

    In this paper the composition of the interface of TiN and TiCN hard coatings deposited onto high speed steel substrates obtained by the arc discharge technique is studied using Auger electron spectroscopy at two different substrate temperatures, 520 K and 720 K. The low temperature (520 K) TiN coating developed an oxygen phase at the interface, producing a weak adherence of 40 N, while the high temperature coatings (720 K) had a less intense oxygen phase, giving a greater adherence to the substrate of 60 N. TiCN coatings at 520 K are characterized by a low oxygen intensity at the interface. However, their adherence of 50 N is lower than the value of 60 N for the high temperature TiN coatings and is independent of the substrate temperature. (orig.)

  20. Promoting a-Al2O3 layer growth upon high temperature oxidation of NiCoCrAlY alloys

    NARCIS (Netherlands)

    Nijdam, T.J.

    2005-01-01

    The turbine blades in gas turbine engines need to be protected against high temperature oxidation and corrosion with a coating system. This coating system comprises of a Ni-based superalloy substrate, a NiCoCrAlY bond coating (BC) and an insulating ceramic thermal barrier coating (TBC). Good

  1. Temperature controlled infrared broadband cloaking with the bilayer coatings of semiconductor and superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaohua [College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); College of Physics and Electronics, Yancheng Teachers University, Yancheng 224051 (China); Liu, Youwen, E-mail: ywliu@nuaa.edu.cn [College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Feng, Yuncai [College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2015-06-15

    Highlights: • We first propose that the cloak is composed of the bilayer of semiconductor and superconductor. • We realize the infrared broadband cloaking based on the scattering cancellation method. • The cloaking frequency can be tuned by external temperature. - Abstract: The infrared broadband tunable cloaking have been proposed and investigated with the bilayer coating materials of semiconductor (n-Ge) and high-temperature superconductor (YBa{sub 2}Cu{sub 3}O{sub 7}), whose cloaking frequency can be controlled by external temperature. The analytical solution is derived based on the scattering cancellation cloaking technique from the Mie scattering theory, and the full-wave numerical simulation is performed by the finite element method. The calculated and simulated results have demonstrated that this invisibility cloak may reduce the total scattering cross section of the composite structure of 90% over a broad frequency band of nearly 20 THz, and the infrared cloaking frequency can be tuned by the external temperature. It can provide a feasible way to design a broadband tunable cloak.

  2. Temperature uniformity mapping in a high pressure high temperature reactor using a temperature sensitive indicator

    NARCIS (Netherlands)

    Grauwet, T.; Plancken, van der I.; Vervoort, L.; Matser, A.M.; Hendrickx, M.; Loey, van A.

    2011-01-01

    Recently, the first prototype ovomucoid-based pressure–temperature–time indicator (pTTI) for high pressure high temperature (HPHT) processing was described. However, for temperature uniformity mapping of high pressure (HP) vessels under HPHT sterilization conditions, this prototype needs to be

  3. New method for evaluating high-quality fog protective coatings

    Science.gov (United States)

    Czeremuszkin, Grzegorz; Latreche, Mohamed; Mendoza-Suarez, Guillermo

    2011-05-01

    Fogging is commonly observed when humid-warm air contacts the cold surface of a transparent substrate, i.e. eyewear lenses, making the observed image blurred and hazy. To protect from fogging, the lens inner surfaces are protected with Anti-Fog coatings, which render them hydrophilic and induce water vapor condensation as a smooth, thin and invisible film, which uniformly flows down on the lens as the condensation progresses. Coatings differ in protection level, aging kinetics, and susceptibility to contamination. Some perform acceptably in limited conditions, beyond which the condensing water film becomes unstable, nonuniform, and scatters light or shows refractory distortions, both affecting the observed image. Quantifying the performance of Anti-Fog coated lenses is difficult: they may not show classical fogging and the existing testing methods, based on fog detection, are therefore inapplicable. The presented method for evaluating and quantifying AF properties is based on characterizing light scattering on lenses exposed to controlled humidity and temperature. Changes in intensity of laser light scattered at low angles (1, 2 4 and 8 degrees), observed during condensation of water on lenses, provide information on the swelling of Anti-Fog coatings, formation of uniform water film, going from an unstable to a steady state, and on the coalescence of discontinuous films. Real time observations/measurements allow for better understanding of factors controlling fogging and fog preventing phenomena. The method is especially useful in the development of new coatings for military-, sport-, and industrial protective eyewear as well as for medical and automotive applications. It allows for differentiating between coatings showing acceptable, good, and excellent performance.

  4. Highly Stretchable and Conductive Superhydrophobic Coating for Flexible Electronics.

    Science.gov (United States)

    Su, Xiaojing; Li, Hongqiang; Lai, Xuejun; Chen, Zhonghua; Zeng, Xingrong

    2018-03-28

    Superhydrophobic materials integrating stretchability with conductivity have huge potential in the emerging application horizons such as wearable electronic sensors, flexible power storage apparatus, and corrosion-resistant circuits. Herein, a facile spraying method is reported to fabricate a durable superhydrophobic coating with excellent stretchable and electrical performance by combing 1-octadecanethiol-modified silver nanoparticles (M-AgNPs) with polystyrene- b-poly(ethylene- co-butylene)- b-polystyrene (SEBS) on a prestretched natural rubber (NR) substrate. The embedding of M-AgNPs in elastic SEBS matrix and relaxation of prestretched NR substrate construct hierarchical rough architecture and endow the coating with dense charge-transport pathways. The fabricated coating exhibits superhydrophobicity with water contact angle larger than 160° and a high conductivity with resistance of about 10 Ω. The coating not only maintains superhydrophobicity at low/high stretch ratio for the newly generated small/large protuberances but also responds to stretching and bending with good sensitivity, broad sensing range, and stable response cycles. Moreover, the coating exhibits excellent durability to heat and strong acid/alkali and mechanical forces including droplet impact, kneading, torsion, and repetitive stretching-relaxation. The findings conceivably stand out as a new tool to fabricate multifunctional superhydrophobic materials with excellent stretchability and conductivity for flexible electronics under wet or corrosive environments.

  5. Advances in High Temperature Gas Cooled Reactor Fuel Technology

    International Nuclear Information System (INIS)

    2012-12-01

    This publication reports on the results of a coordinated research project on advances in high temperature gas cooled reactor (HTGR) fuel technology and describes the findings of research activities on coated particle developments. These comprise two specific benchmark exercises with the application of HTGR fuel performance and fission product release codes, which helped compare the quality and validity of the computer models against experimental data. The project participants also examined techniques for fuel characterization and advanced quality assessment/quality control. The key exercise included a round-robin experimental study on the measurements of fuel kernel and particle coating properties of recent Korean, South African and US coated particle productions applying the respective qualification measures of each participating Member State. The summary report documents the results and conclusions achieved by the project and underlines the added value to contemporary knowledge on HTGR fuel.

  6. Advances in High Temperature Gas Cooled Reactor Fuel Technology

    International Nuclear Information System (INIS)

    2012-06-01

    This publication reports on the results of a coordinated research project on advances in high temperature gas cooled reactor (HTGR) fuel technology and describes the findings of research activities on coated particle developments. These comprise two specific benchmark exercises with the application of HTGR fuel performance and fission product release codes, which helped compare the quality and validity of the computer models against experimental data. The project participants also examined techniques for fuel characterization and advanced quality assessment/quality control. The key exercise included a round-robin experimental study on the measurements of fuel kernel and particle coating properties of recent Korean, South African and US coated particle productions applying the respective qualification measures of each participating Member State. The summary report documents the results and conclusions achieved by the project and underlines the added value to contemporary knowledge on HTGR fuel.

  7. Touch Temperature Coating for Off-the-Shelf Electrical Equipment Used on Spacecraft

    Science.gov (United States)

    Ungar, Eugene K.; Brady, Timothy K.

    2010-01-01

    Off-the-shelf electrical equipment is frequently used in space-based applications to control costs. However, the reduced heat transfer in the spacecraft microgravity environment causes the equipment to operate at significantly higher temperatures than it would in terrestrial applications. This creates touch temperature issues where items particularly metallic ones become too hot for the crew to handle safely. A touch temperature coating layup has been developed that can be added to spacebased electrically powered hardware. The coating allows the crew to safely handle the hardware, but only slightly impedes the heat transfer from the component during normal operation. In the present work, the coating generic requirements are developed and a layup is described that meets these specifications. Analytical and experimental results are presented that demonstrate the ability of the coating layup to increase the allowable limits of touch temperature while only marginally degrading heat transfer to the environment. This allows the spacecraft crew to handle objects that, if not coated, would be hot enough to cause pain or skin damage.

  8. Chemical stability of high-temperature superconductors

    Science.gov (United States)

    Bansal, Narottam P.

    1992-01-01

    A review of the available studies on the chemical stability of the high temperature superconductors (HTS) in various environments was made. The La(1.8)Ba(0.2)CuO4 HTS is unstable in the presence of H2O, CO2, and CO. The YBa2Cu3O(7-x) superconductor is highly susceptible to degradation in different environments, especially water. The La(2-x)Ba(x)CuO4 and Bi-Sr-Ca-Cu-O HTS are relatively less reactive than the YBa2Cu3O(7-x). Processing of YBa2Cu3O(7-x) HTS in purified oxygen, rather than in air, using high purity noncarbon containing starting materials is recommended. Exposure of this HTS to the ambient atmosphere should also be avoided at all stages during processing and storage. Devices and components made out of these oxide superconductors would have to be protected with an impermeable coating of a polymer, glass, or metal to avoid deterioration during use.

  9. Passivation of high temperature superconductors

    Science.gov (United States)

    Vasquez, Richard P. (Inventor)

    1991-01-01

    The surface of high temperature superconductors such as YBa2Cu3O(7-x) are passivated by reacting the native Y, Ba and Cu metal ions with an anion such as sulfate or oxalate to form a surface film that is impervious to water and has a solubility in water of no more than 10(exp -3) M. The passivating treatment is preferably conducted by immersing the surface in dilute aqueous acid solution since more soluble species dissolve into the solution. The treatment does not degrade the superconducting properties of the bulk material.

  10. CONFINEMENT OF HIGH TEMPERATURE PLASMA

    Science.gov (United States)

    Koenig, H.R.

    1963-05-01

    The confinement of a high temperature plasma in a stellarator in which the magnetic confinement has tended to shift the plasma from the center of the curved, U-shaped end loops is described. Magnetic means are provided for counteracting this tendency of the plasma to be shifted away from the center of the end loops, and in one embodiment this magnetic means is a longitudinally extending magnetic field such as is provided by two sets of parallel conductors bent to follow the U-shaped curvature of the end loops and energized oppositely on the inside and outside of this curvature. (AEC)

  11. High temperature superconductors and method

    International Nuclear Information System (INIS)

    Ruvalds, J.J.

    1977-01-01

    This invention comprises a superconductive compound having the formula: Ni/sub 1-x/M/sub x/Z/sub y/ wherein M is a metal which will destroy the magnetic character of nickel (preferably copper, silver or gold); Z is hydrogen or deuterium; x is 0.1 to 0.9; and y, correspondingly, 0.9 to 0.1, and method of conducting electric current with no resistance at relatively high temperature of T>1 0 K comprising a conductor consisting essentially of the superconducting compound noted above

  12. Effects of Wax Coating on the Moisture Loss of Cucumbers at Different Storage Temperatures

    Directory of Open Access Journals (Sweden)

    Jian Li

    2018-01-01

    Full Text Available The effects of wax coating on moisture loss of cucumbers (Cucumis sativus L., cv. Jinglv were investigated at different temperatures. Cucumbers were treated with 10% (volume : volume wax and then stored at 15, 20, 25, or 30°C and 55% relative humidity. The changes in the mass of samples were recorded every 6 h. Results showed that wax coating along with low temperature was very effective in preventing moisture loss of cucumbers during simulated distribution. After 48 h storage, moisture loss in wax treated cucumbers at 15°C was 45% lower than the control at 30°C. Furthermore, a kinetic model was developed to study the influence of temperature on moisture loss based on the Arrhenius law. The model successfully described changes in cucumber moisture loss at different temperatures during storage. The shelf life of cucumber was also predicted using the kinetic model. A synergistic effect was found between wax coating and storage temperature on cucumber shelf life. Wax coating combined with low storage temperature was an effective method to extend the shelf life of cucumber fruit.

  13. An inexpensive high-temperature optical fiber thermometer

    International Nuclear Information System (INIS)

    Moore, Travis J.; Jones, Matthew R.; Tree, Dale R.; Allred, David D.

    2017-01-01

    An optical fiber thermometer consists of an optical fiber whose tip is coated with a highly conductive, opaque material. When heated, this sensing tip becomes an isothermal cavity that emits like a blackbody. This emission is used to predict the sensing tip temperature. In this work, analytical and experimental research has been conducted to further advance the development of optical fiber thermometry. An inexpensive optical fiber thermometer is developed by applying a thin coating of a high-temperature cement onto the tip of a silica optical fiber. An FTIR spectrometer is used to detect the spectral radiance exiting the fiber. A rigorous mathematical model of the irradiation incident on the detection system is developed. The optical fiber thermometer is calibrated using a blackbody radiator and inverse methods are used to predict the sensing tip temperature when exposed to various heat sources. - Highlights: • An inexpensive coating for an optical fiber thermometer sensing tip is tested. • Inverse heat transfer methods are used to estimate the sensing tip temperature. • An FTIR spectrometer is used as the detector to test the optical fiber thermometer using various heat sources.

  14. Development of novel protective high temperature coatings on heat exchanger steels and their corrosion resistance in simulated coal firing environment; Developpement de revetements pour les aciers d'echangeurs thermiques et amelioration de leur resistance a la corrosion en environnement simulant les fumees de combustion et de charbon

    Energy Technology Data Exchange (ETDEWEB)

    Rohr, V.

    2005-10-15

    Improving the efficiencies of thermal power plants requires an increase of the operating temperatures and thus of the corrosion resistance of heat exchanger materials. Therefore, the present study aimed at developing protective coatings using the pack cementation process. Two types of heat exchanger steels were investigated: a 17% Cr-13% Ni austenitic steel and three ferritic-martensitic steels with 9 (P91 and P92) and 12% Cr (HCM12A). The austenitic steel was successfully aluminized at 950 C. For the ferritic-martensitic steels, the pack cementation temperature was decreased down to 650 C, in order to maintain their initial microstructure. Two types of aluminides, made of Fe{sub 2}Al{sub 5} and FeAl, were developed. A mechanism of the coating formation at low temperature is proposed. Furthermore, combining the pack cementation with the conventional heat treatment of P91 allowed to take benefit of higher temperatures for the deposition of a two-step Cr+Al coating. The corrosion resistance of coated and uncoated steels is compared in simulated coal firing environment for durations up to 2000 h between 650 and 700 C. It is shown that the coatings offer a significant corrosion protection and, thus, an increase of the component lifetime. Finally, the performance of coated 9-12% Cr steels is no longer limited by corrosion but by interdiffusion between the coating and the substrate. (author)

  15. Modern high-temperature superconductivity

    International Nuclear Information System (INIS)

    Ching Wu Chu

    1988-01-01

    Ever since the discovery of superconductivity in 1911, its unusual scientific challenge and great technological potential have been recognized. For the past three-quarters of a century, superconductivity has done well on the science front. This is because sueprconductivity is interesting not only just in its own right but also in its ability to act as a probe to many exciting nonsuperconducting phenomena. For instance, it has continued to provide bases for vigorous activities in condensed matter science. Among the more recent examples are heavy-fermion systems and organic superconductors. During this same period of time, superconductivity has also performed admirably in the applied area. Many ideas have been conceived and tested, making use of the unique characteristics of superconductivity - zero resistivity, quantum interference phenomena, and the Meissner effect. In fact, it was not until late January 1987 that it became possible to achieve superconductivity with the mere use of liquid nitrogen - which is plentiful, cheap, efficient, and easy to handle - following the discovery of supercondictivity above 90 K in Y-Ba-Cu-O, the first genuine quaternary superconductor. Superconductivity above 90 K poses scientific and technological challenges not previously encountered: no existing theories can adequately describe superconductivity above 40 K and no known techniques can economically process the materials for full-scale applications. In this paper, therefore, the author recalls a few events leading to the discovery of the new class of quaternary compounds with a superconducting transition temperature T c in the 90 K range, describes the current experimental status of high-temperature superconductivity and, finally, discusses the prospect of very-high-temperature superconductivity, i.e., with a T c substantially higher than 100 K. 97 refs., 7 figs

  16. Low-temperature synthesis of nanocrystalline ZrC coatings on flake graphite by molten salts

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Jun, E-mail: dingjun@wust.edu.cn; Guo, Ding; Deng, Chengji; Zhu, Hongxi; Yu, Chao

    2017-06-15

    Highlights: • Uniform ZrC coatings are prepared on flake graphite at 900 °C. • ZrC coatings are composed of nanosized (30–50 nm) particles. • The template growth mechanism is believed to be dominant in the molten salt synthesis process. - Abstract: A novel molten salt synthetic route has been developed to prepare nanocrystalline zirconium carbide (ZrC) coatings on flake graphite at 900 °C, using Zr powder and flake graphite as the source materials in a static argon atmosphere, along with molten salts as the media. The effects of different molten salt media, the sintered temperature, and the heat preservation time on the phase and microstructure of the synthetic materials were investigated. The ZrC coatings formed on the flake graphite were uniform and composed of nanosized particles (30–50 nm). With an increase in the reaction temperature, the ZrC nanosized particles were more denser, and the heat preservation time and thickness of the ZrC coating also increased accordingly. Electron microscopy was used to observe the ZrC coatings on the flake graphite, indicating that a “template mechanism” played an important role during the molten salt synthesis.

  17. Studies of high temperature superconductors

    International Nuclear Information System (INIS)

    Narlikar, A.

    1989-01-01

    The high temperature superconductors (HTSCs) discovered are from the family of ceramic oxides. Their large scale utilization in electrical utilities and in microelectronic devices are the frontal challenges which can perhaps be effectively met only through consolidated efforts and expertise of a multidisciplinary nature. During the last two years the growth of the new field has occurred on an international scale and perhaps has been more rapid than in most other fields. There has been an extraordinary rush of data and results which are continually being published as short texts dispersed in many excellent journals, some of which were started to ensure rapid publication exclusively in this field. As a result, the literature on HTSCs has indeed become so massive and so diffuse that it is becoming increasingly difficult to keep abreast with the important and reliable facets of this fast-growing field. This provided the motivation to evolve a process whereby both professional investigators and students can have ready access to up-to- date in-depth accounts of major technical advances happening in this field. The present series Studies of High Temperature Superconductors has been launched to, at least in part, fulfill this need

  18. High temperature superconductor current leads

    International Nuclear Information System (INIS)

    Zeimetz, B.; Liu, H.K.; Dou, S.X.

    1996-01-01

    Full text: The use of superconductors in high electrical current applications (magnets, transformers, generators etc.) usually requires cooling with liquid Helium, which is very expensive. The superconductor itself produces no heat, and the design of Helium dewars is very advanced. Therefore most of the heat loss, i.e. Helium consumption, comes from the current lead which connects the superconductor with its power source at room temperature. The current lead usually consists of a pair of thick copper wires. The discovery of the High Temperature Superconductors makes it possible to replace a part of the copper with superconducting material. This drastically reduces the heat losses because a) the superconductor generates no resistive heat and b) it is a very poor thermal conductor compared with the copper. In this work silver-sheathed superconducting tapes are used as current lead components. The work comprises both the production of the tapes and the overall design of the leads, in order to a) maximize the current capacity ('critical current') of the superconductor, b) minimize the thermal conductivity of the silver clad, and c) optimize the cooling conditions

  19. Container floor at high temperatures

    International Nuclear Information System (INIS)

    Reutler, H.; Klapperich, H.J.; Mueller-Frank, U.

    1978-01-01

    The invention describes a floor for container which is stressed at high, changing temperatures and is intended for use in gas-cooled nuclear reactors. Due to the downward cooling gas flow in these types of reactor, the reactor floor is subjected to considerable dimensional changes during switching on and off. In the heating stage, the whole graphite structure of the reactor core and floor expands. In order to avoid arising constraining forces, sufficiently large expansion spaces must be allowed for furthermore restoring forces must be present to close the gaps again in the cooling phase. These restoring forces must be permanently present to prevent loosening of the core cuits amongst one another and thus uncontrollable relative movement. Spring elements are not suitable due to fast fatigue as a result of high temperatures and radiation exposure. It is suggested to have the floor elements supported on rollers whose rolling planes are downwards inclined to a fixed point for support. The construction is described in detail by means of drawings. (GL) [de

  20. High Temperature Radio Frequency Loads

    CERN Document Server

    Federmann, S; Grudiev, A; Montesinos, E; Syratchev, I

    2011-01-01

    In the context of energy saving and recovery requirements the design of reliable and robust RF power loads which permit a high outlet temperature and high pressure of the cooling water is desirable. Cooling water arriving at the outlet withmore than 150 ◦C and high pressure has a higher value than water with 50 ◦C under low pressure. Conventional RF power loads containing dielectric and magnetic materials as well as sensitive ceramic windows usually do not permit going much higher than 90 ◦C. Here we present and discuss several design concepts for "metal only" RF high power loads. One concept is the application of magnetic steel corrugated waveguides near cutoff – this concept could find practical use above several GHz. Another solution are resonant structures made of steel to be installed in large waveguides for frequencies of 500 MHz or lower. Similar resonant structures above 100 MHz taking advantage of the rather high losses of normal steel may also be used in coaxial line geometries with large di...

  1. The primary circuit of the dragon high temperature reactor experiment

    International Nuclear Information System (INIS)

    Simon, R.

    2005-01-01

    The 20 MWth Dragon Reactor Experiment was the first HTGR (High Temperature Gas-cooled Reactor) with coated particle fuel. Its purpose was to test fuel and materials for the High Temperature Reactor programmes pursued in Europe 40 years ago. This paper describes the design and construction of the primary (helium) circuit. It summarizes the main design objectives, lists the performance data and explains the flow paths of the heat removal and helium purification systems. The principal circuit accidents postulated are discussed and the choice of the main construction materials is given. (author)

  2. A long-term ultrahigh temperature application of layered silicide coated Nb alloy in air

    Science.gov (United States)

    Sun, Jia; Fu, Qian-Gang; Li, Tao; Wang, Chen; Huo, Cai-Xia; Zhou, Hong; Yang, Guan-Jun; Sun, Le

    2018-05-01

    Nb-based alloy possessed limited application service life at ultrahigh temperature (>1400 °C) in air even taking the effective protective coating strategy into consideration for last decades. In this work a long duration of above 128 h at 1500 °C in air was successfully achieved on Nb-based alloy thanked to multi-layered silicide coating. Through optimizing interfaces, the MoSi2/NbSi2 silicide coating with Al2O3-adsorbed-particles layer exhibited three-times higher of oxidation resistance capacity than the one without it. In MoSi2-Al2O3-NbSi2 multilayer coating, the Al2O3-adsorbed-particles layer playing as an element-diffusion barrier role, as well as the formed porous Nb5Si3 layer as a stress transition zone, contributed to the significant improvement.

  3. Flagellin based biomimetic coatings: From cell-repellent surfaces to highly adhesive coatings.

    Science.gov (United States)

    Kovacs, Boglarka; Patko, Daniel; Szekacs, Inna; Orgovan, Norbert; Kurunczi, Sandor; Sulyok, Attila; Khanh, Nguyen Quoc; Toth, Balazs; Vonderviszt, Ferenc; Horvath, Robert

    2016-09-15

    Biomimetic coatings with cell-adhesion-regulating functionalities are intensively researched today. For example, cell-based biosensing for drug development, biomedical implants, and tissue engineering require that the surface adhesion of living cells is well controlled. Recently, we have shown that the bacterial flagellar protein, flagellin, adsorbs through its terminal segments to hydrophobic surfaces, forming an oriented monolayer and exposing its variable D3 domain to the solution. Here, we hypothesized that this nanostructured layer is highly cell-repellent since it mimics the surface of the flagellar filaments. Moreover, we proposed flagellin as a carrier molecule to display the cell-adhesive RGD (Arg-Gly-Asp) peptide sequence and induce cell adhesion on the coated surface. The D3 domain of flagellin was replaced with one or more RGD motifs linked by various oligopeptides modulating flexibility and accessibility of the inserted segment. The obtained flagellin variants were applied to create surface coatings inducing cell adhesion and spreading to different levels, while wild-type flagellin was shown to form a surface layer with strong anti-adhesive properties. As reference surfaces synthetic polymers were applied which have anti-adhesive (PLL-g-PEG poly(l-lysine)-graft-poly(ethylene glycol)) or adhesion inducing properties (RGD-functionalized PLL-g-PEG). Quantitative adhesion data was obtained by employing optical biochips and microscopy. Cell-adhesion-regulating coatings can be simply formed on hydrophobic surfaces by using the developed flagellin-based constructs. The developed novel RGD-displaying flagellin variants can be easily obtained by bacterial production and can serve as alternatives to create cell-adhesion-regulating biomimetic coatings. In the present work, we show for the first time that. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  4. Coating and curing apparatus and methods

    Science.gov (United States)

    Brophy, Brenor L; Maghsoodi, Sina; Neyman, Patrick J; Gonsalves, Peter R; Hirsch, Jeffrey G; Yang, Yu S

    2015-02-24

    Disclosed are coating apparatus including flow coating and roll-coating that may be used for uniform sol-gel coating of substrates such as glass, solar panels, windows or part of an electronic display. Also disclosed are methods for substrate preparation, flow coating and roll coating. Lastly systems and methods for skin curing sol-gel coatings deposited onto the surface of glass substrates using a high temperature air-knife are disclosed.

  5. Development of Ion-Plasma Coatings for Protecting Intermetallic Refractory Alloys VKNA-1V and VKNA-25 in the Temperature Range of 1200 - 1250°C

    Science.gov (United States)

    Budinovskii, S. A.; Matveev, P. V.; Smirnov, A. A.

    2017-05-01

    Multilayer heat-resistant ion-plasma coatings for protecting the parts of the hot duct of gas-turbine engines produced from refractory nickel alloys based on VKNA intermetallics from high-temperature oxidation are considered. Coatings of the Ni - Cr - Al (Ta, Re, Hf, Y) + Al - Ni - Y systems are tested for high-temperature strength at 1200 and 1250°C. Metallographic and microscopic x-ray spectrum analyses of the structure and composition of the coatings in the initial condition and after the testing are performed. The effect of protective coatings of the Ni - Cr - Al - Hf + Al - Ni - Y systems on the long-term strength of alloys VKNA-1V and VKNA-25 at 1200°C is studied.

  6. WC-3015 alloy (high-temperature alloy)

    International Nuclear Information System (INIS)

    Anon.

    1974-01-01

    WC-3015 Nb alloy containing 28 to 30 Hf, 1 to 2 Zr, 13 to 16 W, 0 to 4 Ta, 0 to 5 Ti, 0.07 to 0.33 C, less than or equal to 0.02 N, less than or equal to 0.03 O, less than or equal to 0.001 H was developed for use at high temperature in oxidizing environments. Its composition can be tailored to meet specific requirements. When WC-3015 is exposed to O at elevated temperature, Hf and Nb oxidized preferentially and HfO 2 dissolves in Nb 2 O 5 to form 6HfO-Nb 2 O 5 . This complex oxide has a tight cubic lattice which resists the diffusion of O into the substrate. During 24-h exposure to air at 2400 0 F, the alloy oxidizes to a depth of approximately 0.035 in. with a surface recession of 0 to 0.004 in. Oxidation resistance of WC-3015 welds and base material can be further enhanced greatly by applying silicide coatings. WC-3015 alloy can be machined by conventional and electrical-discharge methods. It can be hot worked readily by extrusion, forging or rolling. Cold working can be used at room or elevated temperature. It can be welded by the electron-beam or Tig processes. Physical constants, typical mechanical properties at 75 to 2400 0 F, and effects of composition and heat treatment on tensile and stress-rupture properties of the alloy are tabulated

  7. High concentration agglomerate dynamics at high temperatures.

    Science.gov (United States)

    Heine, M C; Pratsinis, S E

    2006-11-21

    The dynamics of agglomerate aerosols are investigated at high solids concentrations that are typical in industrial scale manufacture of fine particles (precursor mole fraction larger than 10 mol %). In particular, formation and growth of fumed silica at such concentrations by chemical reaction, coagulation, and sintering is simulated at nonisothermal conditions and compared to limited experimental data and commercial product specifications. Using recent chemical kinetics for silica formation by SiCl4 hydrolysis and neglecting aerosol polydispersity, the evolution of the diameter of primary particles (specific surface area, SSA), hard- and soft-agglomerates, along with agglomerate effective volume fraction (volume occupied by agglomerate) is investigated. Classic Smoluchowski theory is fundamentally limited for description of soft-agglomerate Brownian coagulation at high solids concentrations. In fact, these high concentrations affect little the primary particle diameter (or SSA) but dominate the soft-agglomerate diameter, structure, and volume fraction, leading to gelation consistent with experimental data. This indicates that restructuring and fragmentation should affect product particle characteristics during high-temperature synthesis of nanostructured particles at high concentrations in aerosol flow reactors.

  8. Transport mechanisms through PE-CVD coatings: influence of temperature, coating properties and defects on permeation of water vapour

    International Nuclear Information System (INIS)

    Kirchheim, Dennis; Jaritz, Montgomery; Hopmann, Christian; Dahlmann, Rainer; Mitschker, Felix; Awakowicz, Peter; Gebhard, Maximilian; Devi, Anjana; Brochhagen, Markus; Böke, Marc

    2017-01-01

    Gas transport mechanisms through plastics are usually described by the temperature-dependent Arrhenius-model and compositions of several plastic layers are represented by the CLT. When it comes to thin films such as plasma-enhanced chemical vapour deposition (PE-CVD) or plasma-enhanced atomic layer deposition (PE-ALD) coatings on substrates of polymeric material, a universal model is lacking. While existing models describe diffusion through defects, these models presume that permeation does not occur by other means of transport mechanisms. This paper correlates the existing transport models with data from water vapour transmission experiments. (paper)

  9. Effect of Annealing Temperature on the Water Contact Angle of PVD Hard Coatings

    Science.gov (United States)

    Yang, Yu-Sen; Cho, Ting-Pin

    2013-01-01

    Various PVD (physical vapor deposition) hard coatings including nitrides and metal-doped diamond-like carbons (Me-DLC) were applied in plastic injection and die-casting molds to improve wear resistance and reduce sticking. In this study, nitrides hcp-AlN (hexagonal close-packed AlN), Cr2N, (CrAl)2N) and Me-DLC (Si-DLC and Cr-DLC) coatings were prepared using a closed field unbalanced magnetron reactive sputtering system. The coatings were annealed in air for 2 h at various temperatures, after which the anti-sticking properties were assessed using water contact angle (WCA) measurements. The as-deposited hcp-AlN, Cr2N and (CrAl)2N coatings exhibit hydrophobic behavior and exhibit respective WCAs of 119°, 106° and 101°. The as-deposited Si-DLC and Cr-DLC coatings exhibit hydrophilic behavior and exhibit respective WCAs of 74° and 88°. The annealed Cr2N and (CrAl)2N coatings exhibit hydrophobic behavior with higher WCAs, while the annealed hcp-AlN, Si-DLC and Cr-DLC coatings are hydrophilic. The increased WCA of the annealed Cr2N and (CrAl)2N coatings is related to their crystal structure and increased roughness. The decreased WCA of the annealed hcp-AlN, Si-DLC and Cr-DLC coatings is related to their crystal structures and has little correlation with roughness. PMID:28811440

  10. Effect of Annealing Temperature on the Water Contact Angle of PVD Hard Coatings.

    Science.gov (United States)

    Yang, Yu-Sen; Cho, Ting-Pin

    2013-08-07

    Various PVD (physical vapor deposition) hard coatings including nitrides and metal-doped diamond-like carbons (Me-DLC) were applied in plastic injection and die-casting molds to improve wear resistance and reduce sticking. In this study, nitrides hcp-AlN (hexagonal close-packed AlN), Cr₂N, (CrAl)₂N) and Me-DLC (Si-DLC and Cr-DLC) coatings were prepared using a closed field unbalanced magnetron reactive sputtering system. The coatings were annealed in air for 2 h at various temperatures, after which the anti-sticking properties were assessed using water contact angle (WCA) measurements. The as-deposited hcp-AlN, Cr₂N and (CrAl)₂N coatings exhibit hydrophobic behavior and exhibit respective WCAs of 119°, 106° and 101°. The as-deposited Si-DLC and Cr-DLC coatings exhibit hydrophilic behavior and exhibit respective WCAs of 74° and 88°. The annealed Cr₂N and (CrAl)₂N coatings exhibit hydrophobic behavior with higher WCAs, while the annealed hcp-AlN, Si-DLC and Cr-DLC coatings are hydrophilic. The increased WCA of the annealed Cr₂N and (CrAl)₂N coatings is related to their crystal structure and increased roughness. The decreased WCA of the annealed hcp-AlN, Si-DLC and Cr-DLC coatings is related to their crystal structures and has little correlation with roughness.

  11. High level waste forms: glass marbles and thermal spray coatings

    International Nuclear Information System (INIS)

    Treat, R.L.; Oma, K.H.; Slate, S.C.

    1982-01-01

    A process that converts high-level waste to glass marbles and then coats the marbles has been developed at Pacific Northwest Laboratory (PNL) under sponsorship of the US Department of Energy. The process consists of a joule-heated glass melter, a marble-making device based on a patent issued to Corning Glass Works, and a coating system that includes a plasma spray coater and a marble tumbler. The process was developed under the Alternative Waste Forms Program which strived to improve upon monolithic glass for immobilizing high-level wastes. Coated glass marbles were found to be more leach-resistant, and the marbles, before coating were found to be very homogeneous, highly impact resistant, and conductive to encapsulation in a metal matric for improved heat transfer and containment. Marbles are also ideally suited for quality assurance and recycling. However, the marble process is more complex, and marbles require a larger number of canisters for waste containment and have a higher surface area than do glass monoliths

  12. Enhancing the oxidation resistance of graphite by applying an SiC coat with crack healing at an elevated temperature

    Science.gov (United States)

    Park, Jae-Won; Kim, Eung-Seon; Kim, Jae-Un; Kim, Yootaek; Windes, William E.

    2016-08-01

    The potential of reducing the oxidation of the supporting graphite components during normal and/or accident conditions in the Very High Temperature Reactor (VHTR) design has been studied. In this work efforts have been made to slow the oxidation process of the graphite with a thin SiC coating (∼ 10 μm). Upon heating at ≥ 1173 K in air, the spallations and cracks were formed in the dense columnar structured SiC coating layer grown on the graphite with a functionally gradient electron beam physical vapor deposition (EB-PVD. In accordance with the formations of these defects, the sample was vigorously oxidized, leaving only the SiC coating layer. Then, efforts were made to heal the surface defects using additional EB-PVD with ion beam bombardment and chemical vapor deposition (CVD). The EB-PVD did not effectively heal the cracks. But, the CVD was more appropriate for crack healing, likely due to its excellent crack line filling capability with a high density and high aspect ratio. It took ∼ 34 min for the 20% weight loss of the CVD crack healed sample in the oxidation test with annealing at 1173 K, while it took ∼ 8 min for the EB-PVD coated sample, which means it took ∼4 times longer at 1173 K for the same weight reduction in this experimental set-up.

  13. The high-temperature reactor

    International Nuclear Information System (INIS)

    Kirchner, U.

    1991-01-01

    The book deals with the development of the German high-temperature reactor (pebble-bed), the design of a prototype plant and its (at least provisional) shut-down in 1989. While there is a lot of material on the HTR's competitor, the fast breeder, literature is very incomplete on HTRs. The author describes HTR's history as a development which was characterised by structural divergencies but not effectively steered and monitored. There was no project-oriented 'community' such as there was for the fast breeder. Also, the new technology was difficult to control there were situations where no one quite knew what was going on. The technical conditions however were not taken as facts but as a basis for interpretation, wishes and reservations. The HTR gives an opportunity to consider the conditions under which large technical projects can be carried out today. (orig.) [de

  14. High temperature industrial heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Berghmans, J. (Louvain Univ., Heverlee (Belgium). Inst. Mechanica)

    1990-01-01

    The present report intends to describe the state of the art of high temperature industrial heat pumps. A description is given of present systems on the market. In addition the research and development efforts on this subject are described. Compression (open as well as closed cycle) systems, as well as absorption heat pumps (including transformers), are considered. This state of the art description is based upon literature studies performed by a team of researchers from the Katholieke Universiteit Leuven, Belgium. The research team also analysed the economics of heat pumps of different types under the present economic conditions. The heat pumps are compared with conventional heating systems. This analysis was performed in order to evaluate the present condition of the heat pump in the European industry.

  15. Faraday imaging at high temperatures

    Science.gov (United States)

    Hackel, Lloyd A.; Reichert, Patrick

    1997-01-01

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid.

  16. Faraday imaging at high temperatures

    International Nuclear Information System (INIS)

    Hackel, L.A.; Reichert, P.

    1997-01-01

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid. 3 figs

  17. Temperature dependence of bending strength for plasma sprayed zirconia coating; Plasuma yosha zirconia himaku no magetsuyosa no ondo izonsei

    Energy Technology Data Exchange (ETDEWEB)

    Arai, M.; Sakuma, T. [Central Research Inst. of Electric Power Industry, Tokyo (Japan)] Mizutani, T. [Tokyo Inst. of Tech. (Japan)] Kishimoto, K. [Tokyo Inst. of Tech. (Japan). Faculty of Engineering] Saito, M. [Toshiba Corp. (Japan). Heavy Apparatus Engineering Lab.

    1998-02-01

    Plasma sprayed zirconia applying to the thermal barrier coating in gas turbine has been developing for protecting the hot parts such as blades and nozzles from high-temperature enviroments. In this paper, four point bending tests under various temperature conditions are conducted on plasma sprayed zirconia and its mechanical properties are examined. Results show that the bending strength at room temperature for plasma sprayed zirconia is much lower than that of sintered zirconia and is decreased with the increase in temperature. However, Weibull modulus at each temperature is relatively large and the dispersion of bending strength is very small in comparison with that of sintered zirconia. It is also clarified by the SEM observations of fracture surface that many defects such as debonding and microcrack are responsible for the lower bending strength. 9 refs., 8 figs., 1 tab.

  18. VO2 /TiN Plasmonic Thermochromic Smart Coatings for Room-Temperature Applications.

    Science.gov (United States)

    Hao, Qi; Li, Wan; Xu, Huiyan; Wang, Jiawei; Yin, Yin; Wang, Huaiyu; Ma, Libo; Ma, Fei; Jiang, Xuchuan; Schmidt, Oliver G; Chu, Paul K

    2018-03-01

    Vanadium dioxide/titanium nitride (VO 2 /TiN) smart coatings are prepared by hybridizing thermochromic VO 2 with plasmonic TiN nanoparticles. The VO 2 /TiN coatings can control infrared (IR) radiation dynamically in accordance with the ambient temperature and illumination intensity. It blocks IR light under strong illumination at 28 °C but is IR transparent under weak irradiation conditions or at a low temperature of 20 °C. The VO 2 /TiN coatings exhibit a good integral visible transmittance of up to 51% and excellent IR switching efficiency of 48% at 2000 nm. These unique advantages make VO 2 /TiN promising as smart energy-saving windows. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. In vitro performance of ceramic coatings obtained by high velocity oxy-fuel spray.

    Science.gov (United States)

    Melero, H; Garcia-Giralt, N; Fernández, J; Díez-Pérez, A; Guilemany, J M

    2014-01-01

    Hydroxyapatite coatings obtained by plasma-spraying have been used for many years to improve biological performance of bone implants, but several studies have drawn attention to the problems arising from high temperatures and the lack of mechanical properties. In this study, plasma-spraying is substituted by high velocity oxy-fuel (HVOF) spray, with lower temperatures reached, and TiO2 is added in low amounts to hydroxyapatite in order to improve the mechanical properties. Four conditions have been tested to evaluate which are those with better biological properties. Viability and proliferation tests, as well as differentiation assays and morphology observation, are performed with human osteoblast cultures onto the studied coatings. The hydroxyapatite-TiO2 coatings maintain good cell viability and proliferation, especially the cases with higher amorphous phase amount and specific surface, and promote excellent differentiation, with a higher ALP amount for these cases than for polystyrene controls. Observation by SEM corroborates this excellent behaviour. In conclusion, these coatings are a good alternative to those used industrially, and an interesting issue would be improving biological behaviour of the worst cases, which in turn show the better mechanical properties.

  20. Microstructure, composition and performance of PVD coatings designed for successful dry high speed milling

    International Nuclear Information System (INIS)

    Muenz, W.-D.; Lembke, M.I.; Lewis, D.B.; Smith, I.J.

    2001-01-01

    Dry high speed machining (HSM), particularly dry high speed milling, demands hard coatings, which exhibit high toughness, high oxidation resistance, a limited amount of residual stress and excellent adhesion to the cemented carbide (CC) substrate. These requirements are met by TiAICrYN coatings grown by the combined cathodic arc/unbalanced magnetron deposition method. Fully sufficient adhesion is achieved by ion implantation of Cr into the CC prior deposition. Residual stress is controlled by an Y - free base layer; high oxidation resistance is provided by an Y - containing 3 μm thick hard coating with 29 GPa hardness and a residual stress well below -7 GPa. Under the influence of temperatures above 800 o C, Y segregates along the columns of TiAIN and plugs the in/out diffusion of elements. A top layer of Y - containing oxynitride reduces the friction against the work piece material (0.9 to 0.65). Cutting tools coated as such may be used for dry milling up to 25 k rpm in steels HRC > 60. (author)

  1. Electric breakdown of high polymer insulating materials at cryogenic temperature

    International Nuclear Information System (INIS)

    Kim, Sanhyon; Yoshino, Katsumi

    1985-01-01

    Cryogenic properties : temperature dependence of E sub(b) and effects of media upon E sub(b) were investigated on several high polymers. Temperature conditions were provided by liquid He (4.2 K), liquid N 2 (77 K) and cryogen (dry ice-methyl alcohol, 194 K). Silicone oil was used also at ambient temperature and elevated temperature. Polymer film coated with gold by vacuum evaporation was placed in cryostat, and high tension from pulse generator was applied to the film. Dielectric breakdowns were detected by oscilloscope and observed visually. The results of experiment are summerized as follow. (1) E sub(b) of film in He is affected by medium remarkably, and covering with 3-methyl pentane is effective for increasing E sub(b). (2) Temperature dependence of E sub(b) was not recognized in cryogenic temperature below liquid N 2 . (3) Temperature characteristic of E sub(b) changes considerably at the critical temperature T sub(c), and T sub(c) is dependent on material. (4) Strength against dielectric breakdown under cryogenic temperature is not affected by bridging caused by irradiation of electron beam. (5) Dielectric breakdown is thought to be caused by electronic process such as electron avalanche. Consequently, for designing insulation for the temperature below liquid He, insulation design for liquid N 2 is thought to be sufficient. However, the degradation and breakdown by mechanical stress under cryogenic temperature must be taken into consideration. (Ishimitsu, A.)

  2. High temperature incineration. Densification of granules from high temperature incineration

    International Nuclear Information System (INIS)

    Voorde, N. van de; Claes, J.; Taeymans, A.; Hennart, D.; Gijbels, J.; Balleux, W.; Geenen, G.; Vangeel, J.

    1982-01-01

    The incineration system of radioactive waste discussed in this report, is an ''integral'' system, which directly transforms a definite mixture of burnable and unburnable radioactive waste in a final product with a sufficient insolubility to be safely disposed of. At the same time, a significant volume reduction occurs by this treatment. The essential part of the system is a high temperature incinerator. The construction of this oven started in 1974, and while different tests with simulated inactive or very low-level active waste were carried out, the whole system was progressively and continuously extended and adapted, ending finally in an installation with completely remote control, enclosed in an alpha-tight room. In this report, a whole description of the plant and of its auxiliary installations will be given; then the already gained experimental results will be summarized. Finally, the planning for industrial operation will be briefly outlined. An extended test with radioactive waste, which was carried out in March 1981, will be discussed in the appendix

  3. High-temperature Gas Reactor (HTGR)

    Science.gov (United States)

    Abedi, Sajad

    2011-05-01

    General Atomics (GA) has over 35 years experience in prismatic block High-temperature Gas Reactor (HTGR) technology design. During this period, the design has recently involved into a modular have been performed to demonstrate its versatility. This versatility is directly related to refractory TRISO coated - particle fuel that can contain any type of fuel. This paper summarized GA's fuel cycle studies individually and compares each based upon its cycle sustainability, proliferation-resistance capabilities, and other performance data against pressurized water reactor (PWR) fuel cycle data. Fuel cycle studies LEU-NV;commercial HEU-Th;commercial LEU-Th;weapons-grade plutonium consumption; and burning of LWR waste including plutonium and minor actinides in the MHR. results show that all commercial MHR options, with the exception of HEU-TH, are more sustainable than a PWR fuel cycle. With LEU-NV being the most sustainable commercial options. In addition, all commercial MHR options out perform the PWR with regards to its proliferation-resistance, with thorium fuel cycle having the best proliferation-resistance characteristics.

  4. Thermal-mechanical fatigue of high temperature structural materials

    Science.gov (United States)

    Renauld, Mark Leo

    Experimental and analytical methods were developed to address the effect of thermal-mechanical strain cycling on high temperature structural materials under uniaxial and biaxial stress states. Two materials were used in the investigation, a nickel-base superalloy of low ductility, IN-738LC and a high ductility material, 316 stainless steel. A uniaxial life prediction model for the IN-738LC material was based on tensile hysteresis energy measured in stabilized, mid-life hysteresis loops. Hold-time effects and temperature cycling were incorporated in the hysteresis energy approach. Crack growth analysis was also included in the model to predict the number of TMF cycles to initiate and grow a fatigue crack through the coating. The nickel-base superalloy, IN-738LC, was primarily tested in out-of-phase (OP) TMF with a temperature range from 482-871sp°C (900-1600sp°F) under continuous and compressive hold-time cycling. IN-738LC fatigue specimens were coated either with an aluminide, NiCoCrAlHfSi overlay or CoNiCrAlY overlay coating on the outer surface of the specimen. Metallurgical failure analysis via optical and scanning electron microscopy, was used to characterize failure behavior of both substrate and coating materials. Type 316 SS was subjected to continuous biaxial strain cycling with an in-phase (IP) TMF loading and a temperature range from 399-621sp°C (750-1150sp°F). As a result, a biaxial TMF life prediction model was proposed on the basis of an extended isothermal fatigue model. The model incorporates a frequency effect and phase factors to assess the different damage mechanisms observed during TMF loading. The model was also applied to biaxial TMF data generated on uncoated IN-738LC.

  5. Effect of substrate temperature and gas flow ratio on the nanocomposite TiAlBN coating

    Energy Technology Data Exchange (ETDEWEB)

    Rosli, Z. M., E-mail: azmr@utem.edu.my; Kwan, W. L., E-mail: kwailoon86@gmail.com; Juoi, J. M., E-mail: jariah@utem.edu.my [Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka (Malaysia)

    2016-07-19

    Nanocomposite TiAlBN (nc-TiAlBN) coatings were successfully deposited via RF magnetron sputtering by varying the nitrogen-to-total gas flow ratio (R{sub N}), and substrate temperature (T{sub S}). All coatings were deposited on AISI 316 substrates using single Ti-Al-BN hot-pressed disc as a target. The grain size, phases, and chemical composition of the coatings were evaluated using glancing angle X-ray diffraction analysis (GAXRD) and X-ray photoelectron spectroscopy (XPS). Results showed that the grains size of the deposited nc-TiAlBN coatings were in the range of 3.5 to 5.7 nm and reached a nitride saturation state as early as 15 % R{sub N}. As the nitrogen concentration decreases, boron concentration increased from 9 at.% to 16.17 at.%. and thus, increase the TiB{sub 2} phase within the coatings. The T{sub S}, however, showed no significant effect either on the crystallographic structure, grain size, or in the chemical composition of the deposited nc-TiAlBN coating.

  6. Effect of substrate temperature and gas flow ratio on the nanocomposite TiAlBN coating

    International Nuclear Information System (INIS)

    Rosli, Z. M.; Kwan, W. L.; Juoi, J. M.

    2016-01-01

    Nanocomposite TiAlBN (nc-TiAlBN) coatings were successfully deposited via RF magnetron sputtering by varying the nitrogen-to-total gas flow ratio (R_N), and substrate temperature (T_S). All coatings were deposited on AISI 316 substrates using single Ti-Al-BN hot-pressed disc as a target. The grain size, phases, and chemical composition of the coatings were evaluated using glancing angle X-ray diffraction analysis (GAXRD) and X-ray photoelectron spectroscopy (XPS). Results showed that the grains size of the deposited nc-TiAlBN coatings were in the range of 3.5 to 5.7 nm and reached a nitride saturation state as early as 15 % R_N. As the nitrogen concentration decreases, boron concentration increased from 9 at.% to 16.17 at.%. and thus, increase the TiB_2 phase within the coatings. The T_S, however, showed no significant effect either on the crystallographic structure, grain size, or in the chemical composition of the deposited nc-TiAlBN coating.

  7. Tribological Behavior of Thermal Spray Coatings, Deposited by HVOF and APS Techniques, and Composite Electrodeposits Ni/SiC at Both Room Temperature and 300 °C

    Directory of Open Access Journals (Sweden)

    A. Lanzutti

    2013-06-01

    Full Text Available The Both the thermal spray and the electroplating coatings are widely used because of their high wear resistance combined with good corrosion resistance. In particular the addition of both micro particles or nano‐particles to the electro deposited coatings could lead to an increase of the mechanical properties, caused by the change of the coating microstructure. The thermal spray coatings were deposited following industrial standards procedures, while the Ni/SiC composite coatings were produced at laboratory scale using both micro‐and nano‐sized ceramic particles. All the produced coatings were characterized regarding their microstructure,mechanical properties and the wear resistance. The tribological properties were analyzed using a tribometer under ball on disk configuration at both room temperature and 300oC. The results showed that the cermet thermal spray coatings have a high wear resistance, while the Ni nano‐composite showed good anti wear properties compared to the harder ceramic/cermet coatings deposited by thermal spray technique.

  8. Highly transparent, stable, and superhydrophobic coatings based on gradient structure design and fast regeneration from physical damage

    International Nuclear Information System (INIS)

    Chen, Zao; Liu, Xiaojiang; Wang, Yan; Li, Jun; Guan, Zisheng

    2015-01-01

    Graphical abstract: - Highlights: • Highly transparent, stable, and superhydrophobic PET film was fabricated by dip-coating way. • The gradient structure is beneficial to both hydrophobicity and transparency. • The superhydrophobic PET film after physical damage can quickly regain by one-step spary. • The fabrication method is available for various substrates and large-scale production. - Abstract: Optical transparency, mechanical flexibility, and fast regeneration are important factors to expand the application of superhydrophobic surfaces. Herein, we fabricated highly transparent, stable, and superhydrophobic coatings through a novel gradient structure design by versatile dip-coating of silica colloid particles (SCPs) and diethoxydimethysiliane cross-linked silica nanoparticles (DDS-SNPs) on polyethylene terephthalate (PET) film and glass, followed by the modification of octadecyltrichlorosiliane (OTCS). When the DDS concentration reached 5 wt%, the modified SCPs/DDS-SNPs coating exhibited a water contact angle (WCA) of 153° and a sliding angle (SA) <5°. Besides, the average transmittance of this superhydrophobic coating on PET film and glass was increased by 2.7% and 1% in the visible wavelength, respectively. This superhydrophobic coating also showed good robustness and stability against water dropping impact, ultrasonic damage, and acid solution. Moreover, the superhydrophobic PET film after physical damage can quickly regain the superhydrophobicity by one-step spray regenerative solution of dodecyltrichlorosilane (DTCS) modified silica nanoparticles at room temperature. The demonstrated method for the preparation and regeneration of superhydrophobic coating is available for different substrates and large-scale production at room temperature.

  9. High Temperature Superconducting Underground Cable

    International Nuclear Information System (INIS)

    Farrell, Roger A.

    2010-01-01

    The purpose of this Project was to design, build, install and demonstrate the technical feasibility of an underground high temperature superconducting (HTS) power cable installed between two utility substations. In the first phase two HTS cables, 320 m and 30 m in length, were constructed using 1st generation BSCCO wire. The two 34.5 kV, 800 Arms, 48 MVA sections were connected together using a superconducting joint in an underground vault. In the second phase the 30 m BSCCO cable was replaced by one constructed with 2nd generation YBCO wire. 2nd generation wire is needed for commercialization because of inherent cost and performance benefits. Primary objectives of the Project were to build and operate an HTS cable system which demonstrates significant progress towards commercial progress and addresses real world utility concerns such as installation, maintenance, reliability and compatibility with the existing grid. Four key technical areas addressed were the HTS cable and terminations (where the cable connects to the grid), cryogenic refrigeration system, underground cable-to-cable joint (needed for replacement of cable sections) and cost-effective 2nd generation HTS wire. This was the worlds first installation and operation of an HTS cable underground, between two utility substations as well as the first to demonstrate a cable-to-cable joint, remote monitoring system and 2nd generation HTS.

  10. High-temperature axion potential

    International Nuclear Information System (INIS)

    Dowrick, N.J.; McDougall, N.A.

    1989-01-01

    We investigate the possibility of new terms in the high-temperature axion potential arising from the dynamical nature of the axion field and from higher-order corrections to the θ dependence in the free energy of the quark-gluon plasma. We find that the dynamical nature of the axion field does not affect the potential but that the higher-order effects lead to new terms in the potential which are larger than the term previously considered. However, neither the magnitude nor the sign of the potential can be calculated by a perturbative expansion of the free energy since the coupling is too large. We show that a change in the magnitude of the potential does not significantly affect the bound on the axion decay constant but that the sign of the potential is of crucial importance. By investigating the formal properties of the functional integral within the instanton dilute-gas approximation, we find that the sign of the potential does not change and that the minimum remains at θ=0. We conclude that the standard calculation of the axion energy today is not significantly modified by this investigation

  11. Creep of high temperature composites

    International Nuclear Information System (INIS)

    Sadananda, K.; Feng, C.R.

    1993-01-01

    High temperature creep deformation of composites is examined. Creep of composites depends on the interplay of many factors. One of the basic issues in the design of the creep resistant composites is the ability to predict their creep behavior from the knowledge of the creep behavior of the individual components. In this report, the existing theoretical models based on continuum mechanics principles are reviewed. These models are evaluated using extensive experimental data on molydisilicide-silicon carbide composites obtained by the authors. The analysis shows that the rule of mixture based on isostrain and isostress provides two limiting bounds wherein all other theoretical predictions fall. For molydisilicide composites, the creep is predominantly governed by the creep of the majority phase, i.e. the matrix with fibers deforming elastically. The role of back stresses both on creep rates and activation energies are shown to be minimum. Kinetics of creep in MoSi 2 is shown to be controlled by the process of dislocation glide with climb involving the diffusion of Mo atoms

  12. Coping with heat: function of the natal coat of cape fur seal (Arctocephalus Pusillus Pusillus pups in maintaining core body temperature.

    Directory of Open Access Journals (Sweden)

    Nicola Erdsack

    Full Text Available Cape fur seal (Arctocephalus pusillus pups spend the first weeks of life exclusively or mainly ashore. They are exposed to intense solar radiation and high temperatures for long time periods, which results in temperatures up to at least 80°C on their black natal coat. To test the hypothesis that the natal coat has a crucial function in coping with these extreme conditions, we investigated the insulating properties of the natal coat in six captive newborn Cape fur seals during the first 50 days after birth. The natal fur differs from the adult fur not only in colour, but also in density, structure, and water repellence. We measured temperature on the fur surface and within the fur, as well as skin and rectal temperature under varying environmental conditions, comparable to the species' habitat. Experiments were designed to not influence the spontaneous behaviour of the pups. Rectal temperature was constant as long as the pups stayed dry, even during long-lasting intense solar radiation for up to 3 h. Skin temperature remained close to rectal temperature as long as the fur was dry, while with wet fur, skin temperature was significantly reduced as well. Our results show that the natal coat provides an effective insulation against overheating. The severely reduced insulation of wet natal fur against cold supports the assumption that the natal fur is an adaptation to the pups' terrestrial phase of life.

  13. Machining of high performance workpiece materials with CBN coated cutting tools

    International Nuclear Information System (INIS)

    Uhlmann, E.; Fuentes, J.A. Oyanedel; Keunecke, M.

    2009-01-01

    The machining of high performance workpiece materials requires significantly harder cutting materials. In hard machining, the early tool wear occurs due to high process forces and temperatures. The hardest known material is the diamond, but steel materials cannot be machined with diamond tools because of the reactivity of iron with carbon. Cubic boron nitride (cBN) is the second hardest of all known materials. The supply of such PcBN indexable inserts, which are only geometrically simple and available, requires several work procedures and is cost-intensive. The development of a cBN coating for cutting tools, combine the advantages of a thin film system and of cBN. Flexible cemented carbide tools, in respect to the geometry can be coated. The cBN films with a thickness of up to 2 μm on cemented carbide substrates show excellent mechanical and physical properties. This paper describes the results of the machining of various workpiece materials in turning and milling operations regarding the tool life, resultant cutting force components and workpiece surface roughness. In turning tests of Inconel 718 and milling tests of chrome steel the high potential of cBN coatings for dry machining was proven. The results of the experiments were compared with common used tool coatings for the hard machining. Additionally, the wear mechanisms adhesion, abrasion, surface fatigue and tribo-oxidation were researched in model wear experiments.

  14. Design Optimization of Liquid Fueled High Velocity Oxy- Fuel Thermal Spraying Technique for Durable Coating for Fossil Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Choudhuri, Ahsan [Univ. of Texas, El Paso, TX (United States); Love, Norman [Univ. of Texas, El Paso, TX (United States)

    2016-11-04

    High-velocity oxy–fuel (HVOF) thermal spraying was developed in 1930 and has been commercially available for twenty-five years. HVOF thermal spraying has several benefits over the more conventional plasma spray technique including a faster deposition rate which leads to quicker turn-around, with more durable coatings and higher bond strength, hardness and wear resistance due to a homogeneous distribution of the sprayed particles. HVOF thermal spraying is frequently used in engineering to deposit cermets, metallic alloys, composites and polymers, to enhance product life and performance. HVOF thermal spraying system is a highly promising technique for applying durable coatings on structural materials for corrosive and high temperature environments in advanced ultra-supercritical coal- fired (AUSC) boilers, steam turbines and gas turbines. HVOF thermal spraying is the preferred method for producing coatings with low porosity and high adhesion. HVOF thermal spray process has been shown to be one of the most efficient techniques to deposit high performance coatings at moderate cost. Variables affecting the deposit formation and coating properties include hardware characteristics such as nozzle geometry and spraying distance and process parameters such as equivalence ratio, gas flow density, and powder feedstock. In the spray process, the powder particles experience very high speeds combined with fast heating to the powder material melting point or above. This high temperature causes evaporation of the powder, dissolution, and phase transformations. Due to the complex nature of the HVOF technique, the control and optimization of the process is difficult. In general, good coating quality with suitable properties and required performance for specific applications is the goal in producing thermal spray coatings. In order to reach this goal, a deeper understanding of the spray process as a whole is needed. Although many researchers studied commercial HVOF thermal spray

  15. High Temperature Chemistry at NASA: Hot Topics

    Science.gov (United States)

    Jacobson, Nathan S.

    2014-01-01

    High Temperature issues in aircraft engines Hot section: Ni and Co based Superalloys Oxidation and Corrosion (Durability) at high temperatures. Thermal protection system (TPS) and RCC (Reinforced Carbon-Carbon) on the Space Shuttle Orbiter. High temperatures in other worlds: Planets close to their stars.

  16. Response of parylene-coated NaI(Tl scintillators at low temperature

    Directory of Open Access Journals (Sweden)

    Coron Noël

    2014-01-01

    Full Text Available Despite that it is widely used as a scintillator at room temperature, the hygroscopicity of NaI complicates its handling and limits its application for many purposes, for example as a cryogenic detector. To overcome this problem we study coating materials that can act as humidity barriers, in particular parylene, a polymer that can be deposited in very radiopure, thin and conformal layers. In this work, several NaI(Tl samples coated with 2-5 µm parylene-C were tested at low temperature. Luminescence spectra under X-ray excitation are presented at several temperatures as well as the light output vs temperature at 1.5-300 K. Several thermoluminescence peaks were observed at around 60, 95 and 150 K during warm up to room temperature. The mechanical resistance of the coating under thermal cycles was also investigated, and we observed a degradation of the optical appearance and the light output after cooling down to about 100 mK, which compromises the reusability of the samples.

  17. High temperature vapors science and technology

    CERN Document Server

    Hastie, John

    2012-01-01

    High Temperature Vapors: Science and Technology focuses on the relationship of the basic science of high-temperature vapors to some areas of discernible practical importance in modern science and technology. The major high-temperature problem areas selected for discussion include chemical vapor transport and deposition; the vapor phase aspects of corrosion, combustion, and energy systems; and extraterrestrial high-temperature species. This book is comprised of seven chapters and begins with an introduction to the nature of the high-temperature vapor state, the scope and literature of high-temp

  18. Evaluation of high temperature pressure sensors

    International Nuclear Information System (INIS)

    Choi, In-Mook; Woo, Sam-Yong; Kim, Yong-Kyu

    2011-01-01

    It is becoming more important to measure the pressure in high temperature environments in many industrial fields. However, there is no appropriate evaluation system and compensation method for high temperature pressure sensors since most pressure standards have been established at room temperature. In order to evaluate the high temperature pressure sensors used in harsh environments, such as high temperatures above 250 deg. C, a specialized system has been constructed and evaluated in this study. The pressure standard established at room temperature is connected to a high temperature pressure sensor through a chiller. The sensor can be evaluated in conditions of changing standard pressures at constant temperatures and of changing temperatures at constant pressures. According to the evaluation conditions, two compensation methods are proposed to eliminate deviation due to sensitivity changes and nonlinear behaviors except thermal hysteresis.

  19. Low Thermal Conductivity, High Durability Thermal Barrier Coatings for IGCC Environments

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Eric [Univ. of Connecticut, Storrs, CT (United States); Gell, Maurice [Univ. of Connecticut, Storrs, CT (United States)

    2015-01-15

    Advanced thermal barrier coatings (TBC) are crucial to improved energy efficiency in next generation gas turbine engines. The use of traditional topcoat materials, e.g. yttria-stabilized zirconia (YSZ), is limited at elevated temperatures due to (1) the accelerated undesirable phase transformations and (2) corrosive attacks by calcium-magnesium-aluminum-silicate (CMAS) deposits and moisture. The first goal of this project is to use the Solution Precursor Plasma Spray (SPPS) process to further reduce the thermal conductivity of YSZ TBCs by introducing a unique microstructural feature of layered porosity, called inter-pass boundaries (IPBs). Extensive process optimization accompanied with hundreds of spray trials as well as associated SEM cross-section and laser-flash measurements, yielded a thermal conductivity as low as 0.62 Wm⁻¹K⁻¹ in SPPS YSZ TBCs, approximately 50% reduction of APS TBCs; while other engine critical properties, such as cyclic durability, erosion resistance and sintering resistance, were characterized to be equivalent or better than APS baselines. In addition, modifications were introduced to SPPS TBCs so as to enhance their resistance to CMAS under harsh IGCC environments. Several mitigation approaches were explored, including doping the coatings with Al₂O₃ and TiO₂, applying a CMAS infiltration-inhibiting surface layer, and filling topcoat cracks with blocking substances. The efficacy of all these modifications was assessed with a set of novel CMAS-TBC interaction tests, and the moisture resistance was tested in a custom-built high-temperature moisture rig. In the end, the optimal low thermal conductivity TBC system was selected based on all evaluation tests and its processing conditions were documented. The optimal coating consisted on a thick inner layer of YSZ coating made by the SPPS process having a thermal conductivity 50% lower than standard YSZ coatings topped with a high temperature tolerant CMAS resistant gadolinium

  20. High temperature turbine engine structure

    Energy Technology Data Exchange (ETDEWEB)

    Carruthers, W.D.; Boyd, G.L.

    1993-07-20

    A hybrid ceramic/metallic gas turbine is described comprising; a housing defining an inlet, an outlet, and a flow path communicating the inlet with the outlet for conveying a flow of fluid through the housing, a rotor member journaled by the housing in the flow path, the rotor member including a compressor rotor portion rotatively inducting ambient air via the inlet and delivering this air pressurized to the flow path downstream of the compressor rotor, a combustor disposed in the flow path downstream of the compressor receiving the pressurized air along with a supply of fuel to maintain combustion providing a flow of high temperature pressurized combustion products in the flow path downstream thereof, the rotor member including a turbine rotor portion disposed in the flow path downstream of the combustor and rotatively expanding the combustion products toward ambient for flow from the turbine engine via the outlet, the turbine rotor portion providing shaft power driving the compressor rotor portion and an output shaft portion of the rotor member, a disk-like metallic housing portion journaling the rotor member to define a rotational axis therefore, and a disk-like annular ceramic turbine shroud member bounding the flow path downstream of the combustor and circumscribing the turbine rotor portion to define a running clearance therewith, the disk-like ceramic turbine shroud member having a reference axis coaxial with the rotational axis and being spaced axially from the metallic housing portion in mutually parallel concentric relation therewith and a plurality of spacers disposed between ceramic disk-like shroud member and the metallic disk-like housing portion and circumferentially spaced apart, each of the spacers having a first and second end portion having an end surface adjacent the shroud member and the housing portion respectively, the end surfaces having a cylindrical curvature extending transversely relative to the shroud member and the housing portion.

  1. NOvel Refractory Materials for High Alkali, High Temperature Environments

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, J.G.; Griffin, R. (MINTEQ International, Inc.)

    2011-08-30

    Refractory materials can be limited in their application by many factors including chemical reactions between the service environment and the refractory material, mechanical degradation of the refractory material by the service environment, temperature limitations on the use of a particular refractory material, and the inability to install or repair the refractory material in a cost effective manner or while the vessel was in service. The objective of this project was to address the need for new innovative refractory compositions by developing a family of novel MgO-Al2O3 spinel or other similar magnesia/alumina containing unshaped refractory composition (castables, gunnables, shotcretes, etc) utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques (in-situ phase formation, altered conversion temperatures, accelerated reactions, etc). This family of refractory compositions would then be tailored for use in high-temperature, highalkaline industrial environments like those found in the aluminum, chemical, forest products, glass, and steel industries. A research team was formed to carry out the proposed work led by Oak Ridge National Laboratory (ORNL) and was comprised of the academic institution Missouri University of Science and Technology (MS&T), and the industrial company MINTEQ International, Inc. (MINTEQ), along with representatives from the aluminum, chemical, glass, and forest products industries. The two goals of this project were to produce novel refractory compositions which will allow for improved energy efficiency and to develop new refractory application techniques which would improve the speed of installation. Also methods of hot installation were sought which would allow for hot repairs and on-line maintenance leading to reduced process downtimes and eliminating the need to cool and reheat process vessels.

  2. High-temperature reactor developments in the Netherlands

    International Nuclear Information System (INIS)

    Schram, R.P.C.; Cordfunke, E.H.P.; Heek, A.I. van

    1996-01-01

    The high-temperature reactor development in the Netherlands is embedded in the WHITE reactor program, in which several Dutch research institutes and engineering companies participate. The activities within the WHITE program are focused on the development of a small scale HTR for combined heat and power generation. In 1995, design choices for a pebble bed reactor were made at ECN. The first concept HTR will have a closed cycle helium turbine and a power level of 40 MWth. It is intended to make the market introduction of a commercially competitive HTR feasible. As a part of the HTR program at ECN, chemical aspects of HTR fuel and coated particles are studied. Experimental work on the oxidation resistance of coating materials and fission product attack on coating materials as well as thermochemical calculations of the fuel particles are done at ECN. The concept-HTR of ECN is fuelled with UO 2 , but the use of thorium is considered. The composition of the fuel determines the oxygen potential, which plays a key role in chemical safety of the fuel. Thermochemical calculations of the chemical form of cesium inside the HTR fuel particles were performed for a wide oxygen potential range. The chemical form of cesium determines the cesium pressure inside the fuel particle, which in turn determines the release behavior of Cs from defective particles. At normal operating temperatures and low oxygen potentials, the chemical form of cesium is C 60 Cs. It is known that cesium carbon compounds decompose above 650degC in vacuum. The stability of these compounds in the fuel particles at high temperatures(1000-1600degC) is questioned. Decomposition of these compounds may result in high cesium pressures even at normal operating conditions. Experimental work on the thermodynamic properties of cesium compounds at high temperatures is currently performed. (J.P.N.)

  3. Coated Porous Si for High Performance On-Chip Supercapacitors

    Science.gov (United States)

    Grigoras, K.; Keskinen, J.; Grönberg, L.; Ahopelto, J.; Prunnila, M.

    2014-11-01

    High performance porous Si based supercapacitor electrodes are demonstrated. High power density and stability is provided by ultra-thin TiN coating of the porous Si matrix. The TiN layer is deposited by atomic layer deposition (ALD), which provides sufficient conformality to reach the bottom of the high aspect ratio pores. Our porous Si supercapacitor devices exhibit almost ideal double layer capacitor characteristic with electrode volumetric capacitance of 7.3 F/cm3. Several orders of magnitude increase in power and energy density is obtained comparing to uncoated porous silicon electrodes. Good stability of devices is confirmed performing several thousands of charge/discharge cycles.

  4. Robust Fiber Coatings

    National Research Council Canada - National Science Library

    Goettler, Richard

    2002-01-01

    The highly desired ceramic matrix composite is the one in which the high strength and strain-to-failure is achieved through judicious selection of a fiber coating that can survive the high-temperature...

  5. The Yttrium Effect on Nanoscale Structure, Mechanical Properties, and High-Temperature Oxidation Resistance of (Ti0.6Al0.4)1- x Y x N Multilayer Coatings

    Science.gov (United States)

    Wang, Jingxian; Yazdi, Mohammad Arab Pour; Lomello, Fernando; Billard, Alain; Kovács, András; Schuster, Frédéric; Guet, Claude; White, Timothy J.; Wouters, Yves; Pascal, Céline; Sanchette, Frédéric; Dong, ZhiLi

    2017-09-01

    As machine tool coating specifications become increasingly stringent, the fabrication of protective titanium aluminum nitride (Ti-Al-N) films by physical vapor deposition (PVD) is progressively more demanding. Nanostructural modification through the incorporation of metal dopants can enhance coating mechanical properties. However, dopant selection and their near-atomic-scale role in performance optimization is limited. Here, yttrium was alloyed in multilayered Ti-Al-N films to tune microstructures, microchemistries, and properties, including mechanical characteristics, adhesion, wear resistance, and resilience to oxidation. By regulating processing parameters, the multilayer period (Λ) and Y content could be adjusted, which, in turn, permitted tailoring of grain nucleation and secondary phase formation. With the composition fixed at x = 0.024 in (Ti0.6Al0.4)1- x Y x N and Λ increased from 5.5 to 24 nm, the microstructure transformed from acicular grains with 〈111〉 preferred orientation to equiaxed grains with 〈200〉 texture, while the hardness (40.8 ± 2.8 GPa to 29.7 ± 4.9 GPa) and Young's modulus (490 ± 47 GPa to 424 ± 50 GPa) concomitantly deteriorated. Alternately, when Λ = 5.5 nm and x in (Ti0.6Al0.4)1- x Y x N was raised from 0 to 0.024, the hardness was enhanced (28.7 ± 7.3 GPa to 40.8 ± 2.8 GPa) while adhesion and wear resistance were not compromised. The Ti-Al-N adopted a rock-salt type structure with Y displacing either Ti or Al and stabilizing a secondary wurtzite phase. Moreover, Y effectively retarded coating oxidation at 1073 K (800 °C) in air by inhibiting grain boundary oxygen diffusion.

  6. High-field thermal transports properties of REBCO coated conductors

    CERN Document Server

    Bonura, M

    2015-01-01

    The use of REBCO coated conductors is envisaged for many applications, extending from power cables to high-field magnets. Whatever the case, thermal properties of REBCO tapes play a key role for the stability of superconducting devices. In this work, we present the first study on the longitudinal thermal conductivity (k) of REBCO coated conductors in magnetic fields up to 19 T applied both parallelly and perpendicularly to the thermal-current direction. Copper-stabilized tapes from six industrial manufacturers have been investigated. We show that zero-field k of coated conductors can be calculated with an accuracy of ‡ 15% from the residual resistivity ratio of the stabilizer and the Cu/non-Cu ratio. Measurements performed at high fields have allowed us to evaluate the consistency of the procedures generally used for estimating in-field k in the framework of the Wiedemann-Franz law from an electrical characterization of the materials. In-field data are intended to provide primary ingredients for the ...

  7. Parylene C coating for high-performance replica molding.

    Science.gov (United States)

    Heyries, Kevin A; Hansen, Carl L

    2011-12-07

    This paper presents an improvement to the soft lithography fabrication process that uses chemical vapor deposition of poly(chloro-p-xylylene) (parylene C) to protect microfabricated masters and to improve the release of polymer devices following replica molding. Chemical vapor deposition creates nanometre thick conformal coatings of parylene C on silicon wafers having arrays of 30 μm high SU8 pillars with densities ranging from 278 to 10,040 features per mm(2) and aspect ratios (height : width) from 1 : 1 to 6 : 1. A single coating of parylene C was sufficient to permanently promote poly(dimethyl)siloxane (PDMS) mold release and to protect masters for an indefinite number of molding cycles. We also show that the improved release properties of parylene treated masters allow for fabrication with hard polymers, such as poly(urethane), that would otherwise not be compatible with SU8 on silicon masters. Parylene C provides a robust and high performance mold release coating for soft lithography microfabrication that extends the life of microfabricated masters and improves the achievable density and aspect ratio of replicated features.

  8. Contribution to high-temperature chromatography and high-temperature-gas-chromatography-mass spectrometry of lipids

    International Nuclear Information System (INIS)

    Aichholz, R.

    1998-04-01

    This thesis describes the use of high temperature gas chromatography for the investigation of unusual triacylglycerols, cyanolipids and bees waxes. The used glass capillary columns were pretreated and coated with tailor made synthesized high temperature stable polysiloxane phases. The selective separation properties of the individual columns were tested with a synthetic lipid mixture. Suitable derivatization procedures for the gaschromatographic analyses of neutral lipids, containing multiple bonds as well as hydroxy-, epoxy-, and carboxyl groups, were developed and optimized. Therefore conjugated olefinic-, conjugated olefinic-acetylenic-, hydroxy-, epoxy-, and conjugated olefinic keto triacylglycerols in miscellaneous plant seed oils as well as hydroxy m