Review of an Investigation of Ceramic Coatings for Metallic Turbine Parts and Other High-temperature Applications
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PROTECTIVE COATINGS - METALS↗
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Characteristics of Coplanar Waveguide on Sapphire for High Temperature Applications (25 to 400 C)
This paper presents the characteristics of coplanar waveguide transmission lines fabricated on R-plane sapphire substrates as a function of temperature across the temperature range of 25 to 400 C. Effective permittivity and attenuation are measured on a high temperature probe station. Two techniques are used to obtain the transmission line characteristics, a Thru-Reflect-Line calibration technique that yields the propagation coefficient and resonant stubs. To a first order fit of the data, the effective permittivity and the attenuation increase linearly with temperature
Ponchak, George E.↗
Characteristics of Coplanar Waveguide on Sapphire for High Temperature Applications (25 to 400 degrees C)
This paper presents the characteristics of coplanar waveguide transmission lines fabricated on R-plane sapphire substrates as a function of temperature across the temperature range of 25 to 400 C. Effective permittivity and attenuation are measured on a high temperature probe station. Two techniques are used to obtain the transmission line characteristics, a Thru-Reflect-Line calibration technique that yields the propagation coefficient and resonant stubs. To a first order fit of the data, the effective permittivity and the attenuation increase linearly with temperature.
Ponchak, George E.↗
Low Cost Al-Si Casting Alloy As In-Situ Composite for High Temperature Applications
A new aluminum-silicon (Al-Si) alloy has been successfully developed at NASA- Marshall Space Flight Center (MSFC) that has significant improvement in tensile and fatigue strength at elevated temperatures (500 F-700 F). The alloy offers a number of benefits such as light weight, high hardness, low thermal expansion and high surface wear resistance. In hypereutectic form, this alloy is considered as an in-situ Al-Si composite with tensile strength of about 90% higher than the auto industry 390 alloy at 600 F. This composite is very economically produced by using either conventional permanent steel molds or die casting. The projected material cost is less than $0.90 per pound, and automotive components such as pistons can be cast for high production rate using conventional casting techniques with a low and fully accounted cost. Key Words: Metal matrix composites, In-situ composite, aluminum-silicon alloy, hypereutectic alloy, permanent mold casting, die casting.
Lee, Jonathan A.↗
Development of integrated thermionic circuits for high-temperature applications
Integrated thermionic circuits (ITC) capable of extended operation in ambient temperatures up to 500 C are studied. A set of practical design and performance equations is demonstrated. Experimental results are discussed in which both devices and simple circuits were successfully operated in 5000 C environments for extended periods. It is suggested that ITC's may become an important technology for high temperature instrumentation and control systems in geothermal and other high temperature environments.
Mccormick, J. B.↗
Reliable IR Line Lists for N2O and OCS Isotopologues for High Temperature Applications up to 2000 K
To address the needs of planetary and exoplanetary atmosphere studies towards JWST, HWO and future IR astronomy missions, theoretical IR line lists of Carbonyl Sulfide (OCS) and Nitrous Oxide (N2O) are generated to provide complete, reliable, and consistent IR reference data in the range of 0 - 15,000 cm-1, or wavelength longer than 0.67 Å, for temperature up to 2000 K. The line lists are quantum mechanically computed using spectroscopically accurate potential energy surfaces empirically refined with reliable high-resolution experimental data, and high-quality dipole moment surfaces constructed at CCSD(T) level with aug-cc-pVT/Q/5(+d)Z basis and extrapolations to complete basis set limit. The Ames N2O line list includes the primary isotopologue 14N2 16O (denoted "446") with J=0-210 and E' up to 25,000 cm-1, and 11 minor isotopologues of 15N and 17/18O with J=0-150 and lower E' cutoffs. For OCS, Ames "natural" 296 K line list includes 12 most abundant isotopologues. The intensity contribution of OCS minor isotopologues at higher temperature is non-negligible, e.g., 8.6 ± 4.9% at 1000 K. The 16O12C32S (93.7%) and 16O12C34S (4.2%) transitions are computed with J=0-240 and E'< 22,000 cm-1, plus J=0-150 and E' < 16,000 cm-1 for five more minor isotopologues. Reliable Effective Hamiltonian models (e.g., NOSL-296 for 14N2 16O), experimental data collections, and reliable HITRAN or MARVEL levels are combined with quantum rovibrational calculations to deliver accurate and consistent empirical corrections for line positions. The reliability and accuracy of our IR intensity predictions are demonstrated by comparison with available databases, line lists, and experiments, at both room temperature and at high temperature. The line lists will be freely available to public online at ZENODO and NAS data portal. We acknowledge the financial support from NASA XRP and APRA programs.
Planetary↗
Electron Beam Cured Epoxy Resin Composites for High Temperature Applications
Electron beam curing of Polymer Matrix Composites (PMC's) is a nonthermal, nonautoclave curing process that has been demonstrated to be a cost effective and advantageous alternative to conventional thermal curing. Advantages of electron beam curing include: reduced manufacturing costs; significantly reduced curing times; improvements in part quality and performance; reduced environmental and health concerns; and improvement in material handling. In 1994 a Cooperative Research and Development Agreement (CRADA), sponsored by the Department of Energy Defense Programs and 10 industrial partners, was established to advance the electron beam curing of PMC technology. Over the last several years a significant amount of effort within the CRADA has been devoted to the development and optimization of resin systems and PMCs that match the performance of thermal cured composites. This highly successful materials development effort has resulted in a board family of high performance, electron beam curable cationic epoxy resin systems possessing a wide range of excellent processing and property profiles. Hundreds of resin systems, both toughened and untoughened, offering unlimited formulation and processing flexibility have been developed and evaluated in the CRADA program.
Janke, Christopher J.↗
High-Strength Aluminum Casting Alloy for High-Temperature Applications (MSFC Center Director's Discretionary Fund Final Project No. 97-10)
A new aluminum-silicon alloy has been successfully developed at Marshall Space Flight Center that has a significant improvement in tensile strength at elevated temperatures (550 to 700 F). For instance, the new alloy shows in average tensile strength of at least 90 percent higher than the current 390 aluminum piston alloy tested at 500 F. Compared to conventional aluminum alloys, automotive engines using the new piston alloy will have improved gas mileage, and may produce less air pollution in order to meet the future U.S. automotive legislative requirements for low hydrocarbon emissions. The projected cost for this alloy is less than $0.95/lb, and it readily allows the automotive components to be cast at a high production volume with a low, fully accounted cost. It is economically produced by pouring molten metal directly into conventional permanent steel molds or die casting.
Lee, J. A.↗
Advanced Ceramic Matrix Composites (CMCs) for High Temperature Applications
Advanced ceramic matrix composites (CMCs) are enabling materials for a number of demanding applications in aerospace, energy, and nuclear industries. In the aerospace systems, these materials are being considered for applications in hot sections of jet engines such as the combustor liner, vanes, nozzle components, nose cones, leading edges of reentry vehicles, and space propulsion components. Applications in the energy and environmental industries include radiant heater tubes, heat exchangers, heat recuperators, gas and diesel particulate filters, and components for land based turbines for power generation. These materials are also being considered for use in the first wall and blanket components of fusion reactors. In the last few years, a number of CMC components have been developed and successfully tested for various aerospace and ground based applications. However, a number of challenges still remain slowing the wide scale implementation of these materials. They include robust fabrication and manufacturing, assembly and integration, coatings, property modeling and life prediction, design codes and databases, repair and refurbishment, and cost. Fabrication of net and complex shape components with high density and tailorable matrix properties is quite expensive, and even then various desirable properties are not achievable. In this presentation, a number of examples of successful CMC component development and testing will be provided. In addition, critical need for robust manufacturing, joining and assembly technologies in successful implementation of these systems will be discussed.
Singh, M.↗
MICROBALANCE TECHNIQUES FOR HIGH-TEMPERATURE APPLICATIONS - FURTHER DEVELOPMENTS
Microbalance technique for vaporization rate analysis of refractory substances and description of ion pumping system
VAPORIZATION↗
Metal-metal laminar composites for high temperature applications
A study was conducted to obtain indications of the potentialities of laminar metal-metal composites for elevated temperature use. Most of the composites consisted of multiple layers or laminae of tungsten alternated with laminae of Nichrome V, a ductile, weaker but oxidation-resistant alloy. Composites with 50 volume percent of each phase were tested in tension and stress rupture at temperatures of 871 and 1093 C (1600 and 2000 F) and in impact at 23 and 524 C (73 and 975 F). A tension and a short time stress-rupture test was conducted on specimens of 77 v/o W-Re-Hf-C/23 v/o Inconel alloy 600 at 1093 C (2000 F).
Hoffman, C. A.↗
Metal-metal laminar composites for high-temperature applications.
The potentialities of composites consisting of multiple layers of tungsten alternated by layers of Nichrome V (a ductile, weaker than tungsten, but oxidation resistant alloy) at temperatures on the order of 2000 F are studied experimentally. The highest tensile strengths obtained for the composites were 600 MN/sq m (87,000 psi) at 1600 F and 448 MN/sq m (65,000 psi) at 2000 F. Highest 100-hr stress-rupture strengths at these temperatures were 387 MN/sq m (56,000 psi) and 121 MN/sq m (17,500 psi), respectively.
Hoffman, C. A.↗
Metal-metal laminar composites for high-temperature applications.
A study was conducted to obtain indications of the potentialities of laminar metal-metal composites for elevated-temperature use. Most of the composites consisted of multiple layers or laminae of tungsten alternated with laminae of Nichrome V, a ductile, weaker, but oxidation-resistant alloy. Composites with 50 vol % of each phase made from 0.0025 cm, 0.0125 cm, or 0.050 cm laminae, were tested in tension and stress rupture at temperatures of 871 and 1093 C and in impact at 23 and 524 C. A tension and a short-time stress-rupture test was conducted on specimens of 77 vol % W-Re-Hf-C/23 vol % Inconel Alloy 600 at 1093 C.
Hoffman, C. A.↗
Simulation of space radiation effects on polyimide film materials for high temperature applications
Space environment effects on candidate materials for the solar sail film are determined. Polymers, including metallized polyimides that might be suitable solar radiation receivers, were exposed to combined proton and solar electromagnetic radiation. Each test sample was weighted, to simulate the tension on the polymer when it is stretched into near-planar shape while receiving solar radiation. Exposure rates up to 16 times that expected in Earth orbit were employed, to simulate near-sun solar sailing conditions. Sample appearance, elongation, and shrinkage were monitored, noted, and documented in situ. Thermosetting polyimides showed less degradation or visual change in appearance than thermoplastics.
Fogdall, L. B.↗
Ion plating studies for high temperature applications
An experimental project was undertaken to ion plate, by electron beam evaporation, Al films onto 4340 steel substrates using (and at the time troubleshooting) the custom built V.T.A. 7375 electron beam ion plating system. A careful recent literature and commercial vendor survey indicates possible means of improving the trouble plagued V.T.A. system.
Davis, J. H.↗
Nonlinear Constitutive Relations for High Temperature Applications
The topics of discussion addressed were material behavior, design analysis, deformation kinetics, metallurgical characterization, mechanical subelement models, stress analysis, fracture mechanics, viscoplasticity, and thermal loading.
Source record↗
Self-lubricating coatings for high-temperature applications
Some present-day aeropropulsion systems impose severe demands on the thermal and oxidative stability of lubricant, bearing, and seal materials. These demands will be much more severe for operational systems around the turn of the century. Solid lubricants with maximum temperature capabilities of about 1100 C are known. Unfortunately, none of the solid lubricants with the highest temperature capabilities are effective below approximately 400 C. However, research shows that silver and stable fluorides, such as calcium and barium fluoride act synergistically to provide lubrication from below room temperature to approximately 900 C. Plasma-sprayed, self-lubricating composite coatings that were developed at Lewis are described. Background information is given on coatings, designed as PS100 and PS101, that contain the solid lubricants in a Nichrome matrix. These coatings have low friction coefficients over a wide temperature range, but they have inadequate wear resistance for some long-duration applications. Wear resistance was dramatically improved in a recently developed coating PS200, by replacing the Nichrome matrix material with metal-bonded chromium carbide containing dispersed silver and calcium fluoride/barium fluoride eutectic (CaF2/BaF2). The lubricants control friction and the carbide matrix provides excellent wear resistance. Successful tests of these coatings are discussed.
Sliney, Harold E.↗
B2 aluminides for high temperature applications
The structure, phase composition, and mechanical properties of B2 FeAl and NiAl aluminides are investigated. It is noted that, in both alloys, the room temperature brittleness is of primary concern. In the case of FeAl, significant tensile ductilities of up to 8 percent have been obtained at room temperature in iron-rich alloys. In the case of polycrystalline NiAl, attempts to improve ductility have not so far been successfull. Possible solutions to this problem are examined.
Vedula, K.↗