Thermal Protection Materials Development

NASA Technical Reports Server (NTRS)

Selvaduray, Guna; Cox, Michael

1998-01-01

The main portion of this contract year was spent on the development of materials for high temperature applications. In particular, thermal protection materials were constantly tested and evaluated for thermal shock resistance, high-temperature dimensional stability, and tolerance to hostile environmental effects. The analytical laboratory at the Thermal Protection Materials Branch (TPMB), NASA-Ames played an integral part in the process of materials development of high temperature aerospace applications. The materials development focused mainly on the determination of physical and chemical characteristics of specimens from the various research programs.

High Temperature Semiconductor Process

NASA Technical Reports Server (NTRS)

1998-01-01

A sputtering deposition system capable of depositing large areas of high temperature superconducting materials was developed by CVC Products, Inc. with the support of the Jet Propulsion Laboratory SBIR (Small Business Innovative Research) program. The system was devleoped for NASA to produce high quality films of high temperature superconducting material for microwave communication system components. The system is also being used to deposit ferroelectric material for capacitors and the development of new electro-optical materials.2002103899

New World Vistas: Air and Space Power for the 21st Century, Materials Volume.

DTIC Science & Technology

1996-06-01

derivatives from niche (non-silicon) materials: IR sensors, radars, lasers, and high - temperature , adverse-environment electronics. Investment in these...Develop metastable interstitial composites to create extremely high temperatures for destroying chemical biological warfare agents. " Explosives: 1...synthesize of high temperature materials that will be tailored for specific applications/ components. These materials will tend to have microstructures on

Method of manufacturing a high temperature superconductor with improved transport properties

DOEpatents

Balachandran, Uthamalingam; Siegel, Richard W.; Askew, Thomas R.

2001-01-01

A method of preparing a high temperature superconductor. A method of preparing a superconductor includes providing a powdered high temperature superconductor and a nanophase paramagnetic material. These components are combined to form a solid compacted mass with the paramagnetic material disposed on the grain boundaries of the polycrystaline high temperature superconductor.

Non-graphite crucible for high temperature applications

DOEpatents

Holcombe, Cressie E.; Pfeiler, William A.

1996-01-01

A multi-piece crucible for high temperature applications comprises a tubular side wall member having a lip on the inside surface and a bottom member or members forming a container for containing a melt of a material during a high temperature melt-casting operations. The multi-piece design prevents cracking of the crucible or leakage of the melt from the crucible during the melt-casting operation. The lip of the tubular member supports the bottom member. The contacting surfaces where the lip of the tubular side wall member contacts the bottom member of the multi-piece crucible contains a ceramic sealing material. The ceramic sealing material forms a seal sufficient to prevent the melt of the material from leaking out of the multi-piece crucible during the melt-casting process. The multi-piece crucible is made of a material which is chemically inert to the melt and has structural integrity at the melting point temperature of the melt, or of a material coated with such a material. The multi-piece crucible is contained in a thermal can assembly of a high temperature induction furnace during a high temperature melt-casting operation. One embodiment of the multi-piece crucible comprises a tubular member having a vertical slot filled with a ceramic sealing material to provide expansion of the tubular member without cracking during the high temperature melt-casting operation.

Non-graphite crucible for high temperature applications

DOEpatents

Holcombe, C.E.; Pfeiler, W.A.

1996-01-09

A multi-piece crucible for high temperature applications comprises a tubular side wall member having a lip on the inside surface and a bottom member or members forming a container for containing a melt of a material during a high temperature melt-casting operations. The multi-piece design prevents cracking of the crucible or leakage of the melt from the crucible during the melt-casting operation. The lip of the tubular member supports the bottom member. The contacting surfaces where the lip of the tubular side wall member contacts the bottom member of the multi-piece crucible contains a ceramic sealing material. The ceramic sealing material forms a seal sufficient to prevent the melt of the material from leaking out of the multi-piece crucible during the melt-casting process. The multi-piece crucible is made of a material which is chemically inert to the melt and has structural integrity at the melting point temperature of the melt, or of a material coated with such a material. The multi-piece crucible is contained in a thermal can assembly of a high temperature induction furnace during a high temperature melt-casting operation. One embodiment of the multi-piece crucible comprises a tubular member having a vertical slot filled with a ceramic sealing material to provide expansion of the tubular member without cracking during the high temperature melt-casting operation. 9 figs.

Diamond anvil cell for spectroscopic investigation of materials at high temperature, high pressure and shear

DOEpatents

Westerfield, Curtis L.; Morris, John S.; Agnew, Stephen F.

1997-01-01

Diamond anvil cell for spectroscopic investigation of materials at high temperature, high pressure and shear. A cell is described which, in combination with Fourier transform IR spectroscopy, permits the spectroscopic investigation of boundary layers under conditions of high temperature, high pressure and shear.

NDE standards for high temperature materials

NASA Technical Reports Server (NTRS)

Vary, Alex

1991-01-01

High temperature materials include monolithic ceramics for automotive gas turbine engines and also metallic/intermetallic and ceramic matrix composites for a range of aerospace applications. These are materials that can withstand extreme operating temperatures that will prevail in advanced high-efficiency gas turbine engines. High temperature engine components are very likely to consist of complex composite structures with three-dimensionality interwoven and various intermixed ceramic fibers. The thermomechanical properties of components made of these materials are actually created in-place during processing and fabrication stages. The complex nature of these new materials creates strong incentives for exact standards for unambiguous evaluations of defects and microstructural characteristics. NDE techniques and standards that will ultimately be applicable to production and quality control of high temperature materials and structures are still emerging. The needs range from flaw detection to below 100 micron levels in monolithic ceramics to global imaging of fiber architecture and matrix densification anomalies in composites. The needs are different depending on the processing stage, fabrication method, and nature of the finished product. The standards are discussed that must be developed in concert with advances in NDE technology, materials processing research, and fabrication development. High temperature materials and structures that fail to meet stringent specifications and standards are unlikely to compete successfully either technologically or in international markets.

Superconductor-normal-superconductor with distributed Sharvin point contacts

DOEpatents

Holcomb, Matthew J.; Little, William A.

1994-01-01

A non-linear superconducting junction device comprising a layer of high transient temperature superconducting material which is superconducting at an operating temperature, a layer of metal in contact with the layer of high temperature superconducting material and which remains non-superconducting at the operating temperature, and a metal material which is superconducting at the operating temperature and which forms distributed Sharvin point contacts with the metal layer.

Invited Article: Indenter materials for high temperature nanoindentation

NASA Astrophysics Data System (ADS)

Wheeler, J. M.; Michler, J.

2013-10-01

As nanoindentation at high temperatures becomes increasingly popular, a review of indenter materials for usage at high temperatures is instructive for identifying appropriate indenter-sample materials combinations to prevent indenter loss or failure due to chemical reactions or wear during indentation. This is an important consideration for nanoindentation as extremely small volumes of reacted indenter material will have a significant effect on measurements. The high temperature hardness, elastic modulus, thermal properties, and chemical reactivities of diamond, boron carbide, silicon carbide, tungsten carbide, cubic boron nitride, and sapphire are discussed. Diamond and boron carbide show the best elevated temperature hardness, while tungsten carbide demonstrates the lowest chemical reactivity with the widest array of elements.

Nonlinear Constitutive Relations for High Temperature Applications, 1986

NASA Technical Reports Server (NTRS)

1988-01-01

The purpose of the symposium was to review the state-of-the-art in nonlinear constitutive modeling of high temperature materials for aeronautics applications and to identify the need for future research and development efforts in this area. Through this symposium, it was recognized that considerable research efforts are urgently needed in the development of nonlinear constitutive relations for high temperature applications. In the aerospace industry this need is further prompted by recent advances in high temperature materials technology and new demands on material and component performance.

New materials drive high-performance aircraft

NASA Technical Reports Server (NTRS)

Ruhmann, Douglas C.; Bates, William F., Jr.; Dexter, H. B.; June, Reid B.

1992-01-01

This report shows how advanced composite materials and new processing methods are enabling lighter, lower cost aircraft structures. High-temperature polymers research will focus on systems capable of 50,000 to 100,000 hours of operation in the 212-400 F temperature range. Prospective materials being evaluated include high-temperature epoxies, toughened bismaleimides, cyanates, thermoplastics, polyimides and other polymers.

High temperature metal hydrides as heat storage materials for solar and related applications.

PubMed

Felderhoff, Michael; Bogdanović, Borislav

2009-01-01

For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 degrees C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described.

High Temperature Metal Hydrides as Heat Storage Materials for Solar and Related Applications

PubMed Central

Felderhoff, Michael; Bogdanović, Borislav

2009-01-01

For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 °C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described. PMID:19333448

UHTC Research at NASA Ames

NASA Technical Reports Server (NTRS)

Johnson, Sylvia M.

2011-01-01

For enhanced aerodynamic performance. Materials for sharp leading edges can be reusable but need different properties because of geometry and very high temperatures. Require materials with significantly higher temperature capabilities, but for short duration. Current shuttle RCC leading edge materials: T approx. 1650 C. Materials for vehicles with sharp leading edges: T>2000 C. >% Figure depicts: High Temperature at Tip and Steep Temperature Gradient. Passive cooling is simplest option to manage the intense heating on sharp leading edges.

Diamond anvil cell for spectroscopic investigation of materials at high temperature, high pressure and shear

DOEpatents

Westerfield, C.L.; Morris, J.S.; Agnew, S.F.

1997-01-14

Diamond anvil cell is described for spectroscopic investigation of materials at high temperature, high pressure and shear. A cell is described which, in combination with Fourier transform IR spectroscopy, permits the spectroscopic investigation of boundary layers under conditions of high temperature, high pressure and shear. 4 figs.

Program for the development of high temperature electrical materials and components

NASA Technical Reports Server (NTRS)

Neff, W. S.; Lowry, L. R.

1972-01-01

Evaluation of high temperature, space-vacuum performance of selected electrical materials and components, high temperature capacitor development, and evaluation, construction, and endurance testing of compression sealed pyrolytic boron nitride slot insulation are described. The first subject above covered the aging evaluation of electrical devices constructed from selected electrical materials. Individual materials performances were also evaluated and reported. The second subject included study of methods of improving electrical performance of pyrolytic boron nitride capacitors. The third portion was conducted to evaluate the thermal and electrical performance of pyrolytic boron nitride as stator slot liner material under varied temperature and compressive loading. Conclusions and recommendations are presented.

Electrostatic Levitation for Studies of Additive Manufactured Materials

NASA Technical Reports Server (NTRS)

SanSoucie, Michael P.; Rogers, Jan R.; Tramel, Terri

2014-01-01

The electrostatic levitation (ESL) laboratory at NASA's Marshall Space Flight Center is a unique facility for investigators studying high temperature materials. The laboratory boasts two levitators in which samples can be levitated, heated, melted, undercooled, and resolidified. Electrostatic levitation minimizes gravitational effects and allows materials to be studied without contact with a container or instrumentation. The lab also has a high temperature emissivity measurement system, which provides normal spectral and normal total emissivity measurements at use temperature. The ESL lab has been instrumental in many pioneering materials investigations of thermophysical properties, e.g., creep measurements, solidification, triggered nucleation, and emissivity at high temperatures. Research in the ESL lab has already led to the development of advanced high temperature materials for aerospace applications, coatings for rocket nozzles, improved medical and industrial optics, metallic glasses, ablatives for reentry vehicles, and materials with memory. Modeling of additive manufacturing materials processing is necessary for the study of their resulting materials properties. In addition, the modeling of the selective laser melting processes and its materials property predictions are also underway. Unfortunately, there is very little data for the properties of these materials, especially of the materials in the liquid state. Some method to measure thermophysical properties of additive manufacturing materials is necessary. The ESL lab is ideal for these studies. The lab can provide surface tension and viscosity of molten materials, density measurements, emissivity measurements, and even creep strength measurements. The ESL lab can also determine melting temperature, surface temperatures, and phase transition temperatures of additive manufactured materials. This presentation will provide background on the ESL lab and its capabilities, provide an approach to using the ESL in supporting the development and modeling of the selective laser melting process for metals, and provide an overview of the results to date.

Development and Evaluation of High Temperature Gaskets for Hypersonic and Reentry Applications

NASA Technical Reports Server (NTRS)

Singh, Mrityunjay; Shpargel, Tarah

2007-01-01

A wide variety of flexible gasket compositions were developed and tested at high temperatures. The gasket material system has high temperature capability. GRABER sealants were very effective in sealing machined ACC-4 composite surfaces. The gasket composition do not bond strongly with the ACC-4 substrate materials. The density of gasket materials can be tailored to show appropriate compressibility.

Arc Jet Screening Tests Of Phase 1 Orbiter Tile Repair Materials and Uncoated RSI High Temperature Emittance Measurements

NASA Technical Reports Server (NTRS)

DelPapa, Steven V.

2005-01-01

Arc jet tests of candidate tile repair materials and baseline Orbiter uncoated reusable surface insulation (RSI) were performed in the Johnson Space Center's (JSC) Atmospheric Reentry Materials and Structures Evaluation Facility (ARMSEF) from June 23, 2003, through August 19, 2003. These tests were performed to screen candidate tile repair materials by verifying the high temperature performance and determining the thermal stability. In addition, tests to determine the surface emissivity at high temperatures and the geometric shrinkage of bare RSI were performed. In addition, tests were performed to determine the surface emissivity at high temperatures and the geometric shrinkage of uncoated RSI.

500 C Electronic Packaging and Dielectric Materials for High Temperature Applications

NASA Technical Reports Server (NTRS)

Chen, Liang-yu; Neudeck, Philip G.; Spry, David J.; Beheim, Glenn M.; Hunter, Gary W.

2016-01-01

High-temperature environment operable sensors and electronics are required for exploring the inner solar planets and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500C. A compatible packaging system is essential for long-term testing and application of high temperature electronics and sensors. High temperature passive components are also necessary for high temperature electronic systems. This talk will discuss ceramic packaging systems developed for high temperature electronics, and related testing results of SiC circuits at 500C and silicon-on-insulator (SOI) integrated circuits at temperatures beyond commercial limit facilitated by these high temperature packaging technologies. Dielectric materials for high temperature multilayers capacitors will also be discussed. High-temperature environment operable sensors and electronics are required for probing the inner solar planets and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500C. A compatible packaging system is essential for long-term testing and eventual applications of high temperature electronics and sensors. High temperature passive components are also necessary for high temperature electronic systems. This talk will discuss ceramic packaging systems developed for high electronics and related testing results of SiC circuits at 500C and silicon-on-insulator (SOI) integrated circuits at temperatures beyond commercial limit facilitated by high temperature packaging technologies. Dielectric materials for high temperature multilayers capacitors will also be discussed.

High-temperature material characterization for multispectral window

NASA Astrophysics Data System (ADS)

Park, James; Arida, Marvin-Ray; Ku, Zahyun; Jang, Woo-Yong; Urbas, Augustine M.

2017-05-01

A microwave cylindrical cavity combined with a laser has been investigated to characterize the temperature dependence of widow materials in the Air Force Research Laboratory (AFRL). This paper discusses the requirements of high temperature RF material characterizations for transparent ceramic materials, such as ALON, that can potentially be used for multispectral windows. The RF cylindrical resonator was designed and the numerical model was studied to characterize the dielectric constant of materials. The dielectric constant can be extracted from the resonant frequency shift based on the cavity perturbation method (CPM), which is sensitive to the sample size and shape. Laser heating was applied to the material under test (MUT), which could easily be heated above 1000°C by the laser irradiation, in order to conduct CPM at high temperature. The temperature distribution in a material was also analyzed to investigate the impact of the thermal properties and the sample shape.

Development of high temperature containerless processing equipment and the design and evaluation of associated systems required for microgravity materials processing and property measurements

NASA Technical Reports Server (NTRS)

Rey, Charles A.

1991-01-01

The development of high temperature containerless processing equipment and the design and evaluation of associated systems required for microgravity materials processing and property measurements are discussed. Efforts were directed towards the following task areas: design and development of a High Temperature Acoustic Levitator (HAL) for containerless processing and property measurements at high temperatures; testing of the HAL module to establish this technology for use as a positioning device for microgravity uses; construction and evaluation of a brassboard hot wall Acoustic Levitation Furnace; construction and evaluation of a noncontact temperature measurement (NCTM) system based on AGEMA thermal imaging camera; construction of a prototype Division of Amplitude Polarimetric Pyrometer for NCTM of levitated specimens; evaluation of and recommendations for techniques to control contamination in containerless materials processing chambers; and evaluation of techniques for heating specimens to high temperatures for containerless materials experimentation.

Development of high temperature containerless processing equipment and the design and evaluation of associated systems required for microgravity materials processing and property measurements

NASA Astrophysics Data System (ADS)

Rey, Charles A.

1991-03-01

The development of high temperature containerless processing equipment and the design and evaluation of associated systems required for microgravity materials processing and property measurements are discussed. Efforts were directed towards the following task areas: design and development of a High Temperature Acoustic Levitator (HAL) for containerless processing and property measurements at high temperatures; testing of the HAL module to establish this technology for use as a positioning device for microgravity uses; construction and evaluation of a brassboard hot wall Acoustic Levitation Furnace; construction and evaluation of a noncontact temperature measurement (NCTM) system based on AGEMA thermal imaging camera; construction of a prototype Division of Amplitude Polarimetric Pyrometer for NCTM of levitated specimens; evaluation of and recommendations for techniques to control contamination in containerless materials processing chambers; and evaluation of techniques for heating specimens to high temperatures for containerless materials experimentation.

Development of high strength, high temperature ceramics

NASA Technical Reports Server (NTRS)

Hall, W. B.

1982-01-01

Improvement in the high-pressure turbopumps, both fuel and oxidizer, in the Space Shuttle main engine were considered. The operation of these pumps is limited by temperature restrictions of the metallic components used in these pumps. Ceramic materials that retain strength at high temperatures and appear to be promising candidates for use as turbine blades and impellers are discussed. These high strength materials are sensitive to many related processing parameters such as impurities, sintering aids, reaction aids, particle size, processing temperature, and post thermal treatment. The specific objectives of the study were to: (1) identify and define the processing parameters that affect the properties of Si3N4 ceramic materials, (2) design and assembly equipment required for processing high strength ceramics, (3) design and assemble test apparatus for evaluating the high temperature properties of Si3N4, and (4) conduct a research program of manufacturing and evaluating Si3N4 materials as applicable to rocket engine applications.

NBS: Materials measurements

NASA Technical Reports Server (NTRS)

Manning, J. R.

1981-01-01

Measurement of materials properties and thermophysical properties is described. The topics discussed are: surface tensions and their variations with temperature and impurities; convection during unidirectional solidification: measurement of high temperature thermophysical properties of tungsten liquid and solid; thermodynamic properties of refractory materials at high temperatures; and experimental and theoretical studies in wetting and multilayer adsorption.

Europa Lander Material Selection Considerations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tappan, Alexander S.; Heller, Mellisa

2017-01-10

Energetic materials (EMs, explosives, pyrotechnics, propellants) provide high-power output of high temperature reaction products. These products can be solid, liquid, or gaseous during reaction or after the products have equilibrated with the surroundings. For example, high explosives typically consist of carbon, hydrogen, nitrogen, and oxygen bonded within a single molecule, and produce almost exclusively gaseous products. Conversely, intermetallics consist of physical mixtures of metals and metalloids, and produce almost exclusively condensed products. Other materials such as pyrotechnics and propellants have intermediate behavior. All energetic materials react in a self-propagating manner that after ignition, does not necessarily require energy input frommore » the surroundings. The range of reaction velocities can range from mm/s for intermetallics, to km/s for high explosives. Energetic material selection depends on numerous requirements specific to the needs of a system. High explosives are used for applications where high pressure gases are necessary for pushing or fracturing materials (e.g., rock, metal) or creating shock waves or air blast. Propellants are used to produce moderate-pressure, high-temperature products without a shock wave. Pyrotechnics are used to produce numerous effects including: high-temperature products, gases, light, smoke, sound, and others. Thermites are used to produce heat, high-temperature products, materials, and other effects that require condensed products. Intermetallics are used to produce high-temperature condensed products and materials, with very little gas production. Numerous categories of energetic materials exist with overlapping definitions, effects, and properties.« less

A high-efficiency thermoelectric converter for space applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metzger, J.D.; El-Genk, M.S.

1990-01-01

This paper presents a concept for using high-temperature superconducting materials in thermoelectric generators (SCTE) to produce electricity at conversion efficiencies approaching 50% of the Carrot efficiency. The SCTE generator is applicable to systems operating in temperature ranges of high-temperature superconducting materials and thus would be a low-grade converter. Operating in cryogenic temperature ranges provides the advantage of inherently increasing the limits of the Carrot efficiency. Potential applications are for systems operating in space where the ambient temperatures are in the cryogenic temperature range. The advantage of using high-temperature superconducting material in a thermoelectric converter is that it would significantly reducemore » or eliminate the Joule heating losses in a thermoelectric element. This paper investigates the system aspects and the material requirements of the SCTE converter concept, and presents a conceptual design and an application for a space power system.« less

A high-efficiency thermoelectric converter for space applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metzger, J.D.; El-Genk, M.S.

1990-12-31

This paper presents a concept for using high-temperature superconducting materials in thermoelectric generators (SCTE) to produce electricity at conversion efficiencies approaching 50% of the Carrot efficiency. The SCTE generator is applicable to systems operating in temperature ranges of high-temperature superconducting materials and thus would be a low-grade converter. Operating in cryogenic temperature ranges provides the advantage of inherently increasing the limits of the Carrot efficiency. Potential applications are for systems operating in space where the ambient temperatures are in the cryogenic temperature range. The advantage of using high-temperature superconducting material in a thermoelectric converter is that it would significantly reducemore » or eliminate the Joule heating losses in a thermoelectric element. This paper investigates the system aspects and the material requirements of the SCTE converter concept, and presents a conceptual design and an application for a space power system.« less

High temperature superconducting composite conductor and method for manufacturing the same

DOEpatents

Holesinger, Terry G.; Bingert, John F.

2002-01-01

A high temperature superconducting composite conductor is provided including a high temperature superconducting material surrounded by a noble metal layer, the high temperature superconducting composite conductor characterized as having a fill factor of greater than about 40. Additionally, the conductor can be further characterized as containing multiple cores of high temperature superconducting material surrounded by a noble metal layer, said multiple cores characterized as having substantially uniform geometry in the cross-sectional dimensions. Processes of forming such a high temperature superconducting composite conductor are also provided.

Radial turbine cooling

NASA Technical Reports Server (NTRS)

Roelke, Richard J.

1992-01-01

Radial turbines have been used extensively in many applications including small ground based electrical power generators, automotive engine turbochargers and aircraft auxiliary power units. In all of these applications the turbine inlet temperature is limited to a value commensurate with the material strength limitations and life requirements of uncooled metal rotors. To take advantage of all the benefits that higher temperatures offer, such as increased turbine specific power output or higher cycle thermal efficiency, requires improved high temperature materials and/or blade cooling. Extensive research is on-going to advance the material properties of high temperature superalloys as well as composite materials including ceramics. The use of ceramics with their high temperature potential and low cost is particularly appealing for radial turbines. However until these programs reach fruition the only way to make significant step increases beyond the present material temperature barriers is to cool the radial blading.

A measurement system of high-temperature oxidation environment with ultrasonic Ir0.6Rth0.4 alloy thermometry.

PubMed

Wei, Yanlong; Wang, Gao; Gao, Yubin; Liu, Zhengguang; Xu, Lin; Tian, Miao; Yuan, Dongfang; Ren, Haiping; Zhou, Hanchang; Yang, Lu; Shi, Xueshun; Xiao, Zhaoqian

2018-04-03

Iridium-rhodium is generally applied as a thermocouple material, with max operating temperature about 2150 °C. In this study, a ultrasonic temperature measurement system was designed by using Iridium-rhodium (60%Ir-40%Rh) alloy as an acoustic waveguide sensor material, and the system was preliminarily tested in a high-temperature oxidation environment. The result of ultrasonic temperature measurement shows that this system can indeed work stably in high-temperature oxidation environments. The relationship between temperature and delay time of ultrasonic thermometry up to 2200 °C was illustrated. Iridium-rhodium materials were also investigated in order to fully elucidate the proposed waveguide sensor's performance in a high-temperature oxidation environment. This system lays a foundation for further application of high-temperature measurement. Copyright © 2018. Published by Elsevier B.V.

Development of a Brazing Alloy for the Mechanically Alloyed High Temperature Sheet Material INCOLOY Alloy MA 956.

DTIC Science & Technology

1981-09-01

OF A BRAZING ALLOY FOR THE MECHANICALLY ALLOYED HIGH TEMPERATURE SHEET MATERIAL INCOLOY ALLOY MA 956 W. E. Morgan and Dr. P. J. Bridges N. Wiggin...PERIOD COVERED DEVELOPMENT OF A BRAZING ALLOY FOR THE Final Report MECHANICALLY ALLOYED HIGH TEMPERATURE Dec 1978 - March 1981 SHEET MATERIAL INCOLOY...block nomber) High temperature ODS alloys, Braze development, Braze alloys, INCOLOY MA 956, Ni-Cr-Pd, Fe-Cr-Pd, Ni-Cr-Ge, Fe-Cr-Ge, Fe-Cr-B, Fe-Cr-Si

High performance dielectric materials development

NASA Technical Reports Server (NTRS)

Piche, Joe; Kirchner, Ted; Jayaraj, K.

1994-01-01

The mission of polymer composites materials technology is to develop materials and processing technology to meet DoD and commercial needs. The following are outlined in this presentation: high performance capacitors, high temperature aerospace insulation, rationale for choosing Foster-Miller (the reporting industry), the approach to the development and evaluation of high temperature insulation materials, and the requirements/evaluation parameters. Supporting tables and diagrams are included.

High performance dielectric materials development

NASA Astrophysics Data System (ADS)

Piche, Joe; Kirchner, Ted; Jayaraj, K.

1994-09-01

The mission of polymer composites materials technology is to develop materials and processing technology to meet DoD and commercial needs. The following are outlined in this presentation: high performance capacitors, high temperature aerospace insulation, rationale for choosing Foster-Miller (the reporting industry), the approach to the development and evaluation of high temperature insulation materials, and the requirements/evaluation parameters. Supporting tables and diagrams are included.

High temperature structural insulating material

DOEpatents

Chen, Wayne Y.

1987-01-06

A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800.degree. C.), low thermal conductivity (below about 0.2 W/m.degree. C.), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800.degree. C., a diameter within the range of 20-200 .mu.m, and a wall thickness in the range of about 2-4 .mu.m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

High temperature structural insulating material

DOEpatents

Chen, Wayne Y.

1987-01-01

A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800.degree. C.), low thermal conductivity (below about 0.2 W/m.degree. C.), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800.degree. C., a diameter within the range of 20-200 .mu.m, and a wall thickness in the range of about 2-4 .mu.m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

High-Temperature Piezoelectric Sensing

PubMed Central

Jiang, Xiaoning; Kim, Kyungrim; Zhang, Shujun; Johnson, Joseph; Salazar, Giovanni

2014-01-01

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. PMID:24361928

Microfabricated thermoelectric power-generation devices

NASA Technical Reports Server (NTRS)

Fleurial, Jean-Pierre (Inventor); Phillips, Wayne (Inventor); Borshchevsky, Alex (Inventor); Kolawa, Elizabeth A. (Inventor); Ryan, Margaret A. (Inventor); Caillat, Thierry (Inventor); Mueller, Peter (Inventor); Snyder, G. Jeffrey (Inventor); Kascich, Thorsten (Inventor)

2002-01-01

A device for generating power to run an electronic component. The device includes a heat-conducting substrate (composed, e.g., of diamond or another high thermal conductivity material) disposed in thermal contact with a high temperature region. During operation, heat flows from the high temperature region into the heat-conducting substrate, from which the heat flows into the electrical power generator. A thermoelectric material (e.g., a BiTe alloy-based film or other thermoelectric material) is placed in thermal contact with the heat-conducting substrate. A low temperature region is located on the side of the thermoelectric material opposite that of the high temperature region. The thermal gradient generates electrical power and drives an electrical component.

Microfabricated thermoelectric power-generation devices

NASA Technical Reports Server (NTRS)

Fleurial, Jean-Pierre (Inventor); Ryan, Margaret A. (Inventor); Borshchevsky, Alex (Inventor); Phillips, Wayne (Inventor); Kolawa, Elizabeth A. (Inventor); Snyder, G. Jeffrey (Inventor); Caillat, Thierry (Inventor); Kascich, Thorsten (Inventor); Mueller, Peter (Inventor)

2004-01-01

A device for generating power to run an electronic component. The device includes a heat-conducting substrate (composed, e.g., of diamond or another high thermal conductivity material) disposed in thermal contact with a high temperature region. During operation, heat flows from the high temperature region into the heat-conducting substrate, from which the heat flows into the electrical power generator. A thermoelectric material (e.g., a BiTe alloy-based film or other thermoelectric material) is placed in thermal contact with the heat-conducting substrate. A low temperature region is located on the side of the thermoelectric material opposite that of the high temperature region. The thermal gradient generates electrical power and drives an electrical component.

Closed-form solution of temperature and heat flux in embedded cooling channels

NASA Astrophysics Data System (ADS)

Griggs, Steven Craig

1997-11-01

An analytical method is discussed for predicting temperature in a layered composite material with embedded cooling channels. The cooling channels are embedded in the material to maintain its temperature at acceptable levels. Problems of this type are encountered in the aerospace industry and include high-temperature or high-heat-flux protection for advanced composite-material skins of high-speed air vehicles; thermal boundary-layer flow control on supersonic transports; or infrared signature suppression on military vehicles. A Green's function solution of the diffusion equation is used to simultaneously predict the global and localized effects of temperature in the material and in the embedded cooling channels. The integral method is used to solve the energy equation with fluid flow to find the solution of temperature and heat flux in the cooling fluid and material simultaneously. This method of calculation preserves the three-dimensional nature of this problem.

Stability of Materials in High Temperature Water Vapor: SOFC Applications

NASA Technical Reports Server (NTRS)

Opila, E. J.; Jacobson, N. S.

2010-01-01

Solid oxide fuel cell material systems require long term stability in environments containing high-temperature water vapor. Many materials in fuel cell systems react with high-temperature water vapor to form volatile hydroxides which can degrade cell performance. In this paper, experimental methods to characterize these volatility reactions including the transpiration technique, thermogravimetric analysis, and high pressure mass spectrometry are reviewed. Experimentally determined data for chromia, silica, and alumina volatility are presented. In addition, data from the literature for the stability of other materials important in fuel cell systems are reviewed. Finally, methods for predicting material recession due to volatilization reactions are described.

Phase change based cooling for high burst mode heat loads with temperature regulation above the phase change temperature

DOEpatents

The United States of America as represented by the United States Department of Energy

2009-12-15

An apparatus and method for transferring thermal energy from a heat load is disclosed. In particular, use of a phase change material and specific flow designs enables cooling with temperature regulation well above the fusion temperature of the phase change material for medium and high heat loads from devices operated intermittently (in burst mode). Exemplary heat loads include burst mode lasers and laser diodes, flight avionics, and high power space instruments. Thermal energy is transferred from the heat load to liquid phase change material from a phase change material reservoir. The liquid phase change material is split into two flows. Thermal energy is transferred from the first flow via a phase change material heat sink. The second flow bypasses the phase change material heat sink and joins with liquid phase change material exiting from the phase change material heat sink. The combined liquid phase change material is returned to the liquid phase change material reservoir. The ratio of bypass flow to flow into the phase change material heat sink can be varied to adjust the temperature of the liquid phase change material returned to the liquid phase change material reservoir. Varying the flowrate and temperature of the liquid phase change material presented to the heat load determines the magnitude of thermal energy transferred from the heat load.

High-Temperature Structures, Adhesives, and Advanced Thermal Protection Materials for Next-Generation Aeroshell Design

NASA Technical Reports Server (NTRS)

Collins, Timothy J.; Congdon, William M.; Smeltzer, Stanley S.; Whitley, Karen S.

2005-01-01

The next generation of planetary exploration vehicles will rely heavily on robust aero-assist technologies, especially those that include aerocapture. This paper provides an overview of an ongoing development program, led by NASA Langley Research Center (LaRC) and aimed at introducing high-temperature structures, adhesives, and advanced thermal protection system (TPS) materials into the aeroshell design process. The purpose of this work is to demonstrate TPS materials that can withstand the higher heating rates of NASA's next generation planetary missions, and to validate high-temperature structures and adhesives that can reduce required TPS thickness and total aeroshell mass, thus allowing for larger science payloads. The effort described consists of parallel work in several advanced aeroshell technology areas. The areas of work include high-temperature adhesives, high-temperature composite materials, advanced ablator (TPS) materials, sub-scale demonstration test articles, and aeroshell modeling and analysis. The status of screening test results for a broad selection of available higher-temperature adhesives is presented. It appears that at least one (and perhaps a few) adhesives have working temperatures ranging from 315-400 C (600-750 F), and are suitable for TPS-to-structure bondline temperatures that are significantly above the traditional allowable of 250 C (482 F). The status of mechanical testing of advanced high-temperature composite materials is also summarized. To date, these tests indicate the potential for good material performance at temperatures of at least 600 F. Application of these materials and adhesives to aeroshell systems that incorporate advanced TPS materials may reduce aeroshell TPS mass by 15% - 30%. A brief outline is given of work scheduled for completion in 2006 that will include fabrication and testing of large panels and subscale aeroshell test articles at the Solar-Tower Test Facility located at Kirtland AFB and operated by Sandia National Laboratories. These tests are designed to validate aeroshell manufacturability using advanced material systems, and to demonstrate the maintenance of bondline integrity at realistically high temperatures and heating rates. Finally, a status is given of ongoing aeroshell modeling and analysis efforts which will be used to correlate with experimental testing, and to provide a reliable means of extrapolating to performance under actual flight conditions. The modeling and analysis effort includes a parallel series of experimental tests to determine TSP thermal expansion and other mechanical properties which are required for input to the analysis models.

Magnetic sensor for high temperature using a laminate composite of magnetostrictive material and piezoelectric material

NASA Astrophysics Data System (ADS)

Ueno, Toshiyuki; Higuchi, Toshiro

2005-05-01

A high sensitive and heat-resistive magnetic sensor using a magnetostrictive/piezoelectric laminate composite is investigated. The sensing principle is based on the magnetostrictive- and piezoelectric effect, whereby a detected yoke displacement is transduced into a voltage on the piezoelectric materials. The sensor is intended to detect the displacement of a ferromagnetic object in a high temperature environment, where conventional magnetic sensors are not useful. Such applications include sensors in engine of automobile and machinery used in material processing. The sensor features combination of a laminate composite of magnetostrictive/piezoelectric materials with high Curie temperatures and an appropriate magnetic circuit to convert mechanical displacement to sensor voltages and suppress temperature fluctuation. This paper describes the sensing principle and shows experimental results using a composite of Terfenol-D and Lithium Niobate to assure high sensitivity of 50V/mm at bias gap of 0.1mm and a temperature operating range over 200 °C.

Acquisition of Raman Spectrometer and High Temperature and Pressure Reactor for Synthesis and Characterization of Carbon Based Hybrid Nanoparticles from Waste Wood

DTIC Science & Technology

2015-04-27

from waste biomass using these two high temperature reactors. We have extensively used a Raman spectrometer to analyse as synthesized carbon materials...corporation). These tools were fully installed and operational. We have also synthesized carbon materials from waste biomass using these two high...materials from waste biomass using these two high temperature reactors. We have extensively used a Raman spectrometer to analyse as synthesized carbon

Processing of extraterrestrial materials by high temperature vacuum vaporization

NASA Technical Reports Server (NTRS)

Grimley, R. T.; Lipschutz, M. E.

1983-01-01

It is noted that problems associated with the extraction and concentration of elements and commpounds important for the construction and operation of space habitats have received little attention. High temperature vacuum vaporization is considered a promising approach; this is a technique for which the space environment offers advantages in the form of low ambient pressures and temperatures and the possibility of sustained high temperatures via solar thermal energy. To establish and refine this new technology, experimental determinations must be made of the material release profiles as a function of temperature, of the release kinetics and chemical forms of material being transported, and of the various means of altering release kinetics. Trace element data determined by neutron activation analysis of meteorites heated to 1400 C in vacuum is summarized. The principal tool, high temperature spectrometry, is used to examine the vaporization thermodynamics and kinetics of major and minor elements from complex multicomponent extraterrestrial materials.

Laser assisted machining: a state of art review

NASA Astrophysics Data System (ADS)

Punugupati, Gurabvaiah; Kandi, Kishore Kumar; Bose, P. S. C.; Rao, C. S. P.

2016-09-01

Difficult-to-cut materials have increasing demand in aerospace and automobile industries due to their high yield stress, high strength to weight ratio, high toughness, high wear resistance, high creep, high corrosion resistivity, ability to retain high strength at high temperature, etc. The machinability of these advanced materials, using conventional methods of machining is typical due to the high temperature and pressure at the cutting zone and tool and properties such as low thermal conductivity, high cutting forces and cutting temperatures makes the materials difficult to machine. Laser assisted machining (LAM) is a new and innovative technique for machining the difficult-to-cut materials. This paper deals with a review on the advances in lasers, tools and the mechanism of machining using LAM and their effects.

High temperature refrigerator

DOEpatents

Steyert, Jr., William A.

1978-01-01

A high temperature magnetic refrigerator 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 said 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.

New materials for high temperature turbines; ONERA's DS composites confronted with blade problems

NASA Technical Reports Server (NTRS)

Bibring, H.

1977-01-01

ONERA's refractory DS composites were cited as materials required for use in advanced aircraft turbines, operating at high temperatures. These materials were found to be reliable in the construction of turbine blades. Requirements for a blade material in aircraft turbines operating at higher temperatures were compared with the actual performance as found in COTAC DS composite testing. The structure and properties of the more fully developed 74 and 741 types were specified. High temperature structural stability, impact of thermal and mechanical fatigue, oxidation resistance and coating capability were thoroughly evaluated. The problem of cooling passages in DS eutectic blades is also outlined.

Mechanical Properties of T650-35/AFR-PE-4 at Elevated Temperatures for Lightweight Aeroshell Designs

NASA Technical Reports Server (NTRS)

Whitley, Karen S.; Collins, TImothy J.

2006-01-01

Considerable efforts have been underway to develop multidisciplinary technologies for aeroshell structures that will significantly increase the allowable working temperature for the aeroshell components, and enable the system to operate at higher temperatures while sustaining performance and durability. As part of these efforts, high temperature polymer matrix composites and fabrication technologies are being developed for the primary load bearing structure (heat shield) of the spacecraft. New high-temperature resins and composite material manufacturing techniques are available that have the potential to significantly improve current aeroshell design. In order to qualify a polymer matrix composite (PMC) material as a candidate aeroshell structural material, its performance must be evaluated under realistic environments. Thus, verification testing of lightweight PMC's at aeroshell entry temperatures is needed to ensure that they will perform successfully in high-temperature environments. Towards this end, a test program was developed to characterize the mechanical properties of two candidate material systems, T650-35/AFR-PE-4 and T650-35/RP46. The two candidate high-temperature polyimide resins, AFR-PE-4 and RP46, were developed at the Air Force Research Laboratory and NASA Langley Research Center, respectively. This paper presents experimental methods, strength, and stiffness data of the T650-35/AFR-PE-4 material as a function of elevated temperatures. The properties determined during the research test program herein, included tensile strength, tensile stiffness, Poisson s ratio, compressive strength, compressive stiffness, shear modulus, and shear strength. Unidirectional laminates, a cross-ply laminate and two eight-harness satin (8HS)-weave laminates (4-ply and 10-ply) were tested according to ASTM standard methods at room and elevated temperatures (23, 316, and 343 C). All of the relevant test methods and data reduction schemes are outlined along with mechanical data. These data contribute to a database of material properties for high-temperature polyimide composites that will be used to identify the material characteristics of potential candidate materials for aeroshell structure applications.

High temperature structural insulating material

DOEpatents

Chen, W.Y.

1984-07-27

A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800/sup 0/C), low thermal conductivity (below about 0.2 W/m/sup 0/C), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800/sup 0/C, a diameter within the range of 20-200 ..mu..m, and a wall thickness in the range of about 2 to 4 ..mu..m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

Behavior of stress generated in semiconductor chips with high-temperature joints: Influence of mechanical properties of joint materials

NASA Astrophysics Data System (ADS)

Ito, H.; Kuwahara, M.; Ohta, R.; Usui, M.

2018-04-01

High-temperature joint materials are indispensable to realizing next-generation power modules with high-output performance. However, crack initiation resulting from stress concentration in semiconductor chips joined with high-temperature joint materials remains a critical problem in high-temperature operation. Therefore, clarifying the quantitative influence of joint materials on the stress generated in chips is essential. This study investigates the stress behavior of chips joined by Ni-Sn solid-liquid interdiffusion (SLID), which results in a high-temperature joint material likely to generate cracks after joining or when under thermal cycling. The results are compared with those fabricated using three types of solders, Pb-10%Sn, Sn-0.7%Cu, and Sn-10%Sb (mass %), which are conventional joint materials with different melting points and mechanical properties. Using Ni-Sn SLID results in the generation of high compressive stress (500 MPa) without stress relaxation after the joining process in contrast to the case of solders in which the compressive stresses are low (<300 MPa) and decrease to still lower levels (<250 MPa). In addition, no stress relaxation occurs during thermal cycling when using Ni-Sn SLID, whereas stress relaxation is clearly observed during heating to 200 °C using solders. Different stress behaviors between Ni-Sn SLID and other joint materials are illustrated by their mechanical strength and resistance against plastic and creep deformation. These results suggest that stress relaxation in a chip is key in suppressing crack initiation in highly reliable modules during high-temperature operation.

Processing and Material Characterization of Continuous Basalt Fiber Reinforced Ceramic Matrix Composites Using Polymer Derived Ceramics.

NASA Technical Reports Server (NTRS)

Cox, Sarah B.

2014-01-01

The need for high performance vehicles in the aerospace industry requires materials which can withstand high loads and high temperatures. New developments in launch pads and infrastructure must also be made to handle this intense environment with lightweight, reusable, structural materials. By using more functional materials, better performance can be seen in the launch environment, and launch vehicle designs which have not been previously used can be considered. The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer matrix composites can be used for temperatures up to 260C. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in the composites. In this study, continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. The oxyacetylene torch testing and three point bend testing have been performed on test panels and the test results are presented.

Advanced Sensor and Packaging Technologies for Intelligent Adaptive Engine Controls (Preprint)

DTIC Science & Technology

2013-05-01

combination of micro-electromechanical systems (MEMS) sensor technology, novel ceramic materials, high - temperature electronics, and advanced harsh...with simultaneous pressure measurements up to 1,000 psi. The combination of a high - temperature , high -pressure-ratio compressor system, and adaptive...combination of micro-electromechanical systems (MEMS) sensor technology, novel ceramic materials, high temperature electronics, and advanced harsh

METHOD AND APPARATUS FOR PRODUCING POWER

DOEpatents

Wollan, E.O.

1961-06-27

A neutronic reactor comprising two discrete zones; namely, an inner zone containing fissionable material and an outer zone containing fertile material is described. The inner zone is operated at a low temperature and is cooled by pressurized water. The outer zone is operated at a substantially higher temperature and is cooled by steam flashed from the inner zone. The reactor is particularly advantageous in that it produces high temperature steam; yet the materials of construction in the core (inner zone) are not restricted to materials capable of withstanding high temperature operation.

Inductively-Charged High-Temperature Superconductors And Methods Of Use

DOEpatents

Bromberg, Leslie

2003-09-16

The invention provides methods of charging superconducting materials and, in particular, methods of charging high-temperature superconducting materials. The methods generally involve cooling a superconducting material to a temperature below its critical temperature. Then, an external magnetic field is applied to charge the material at a nearly constant temperature. The external magnetic field first drives the superconducting material to a critical state and then penetrates into the material. When in the critical state, the superconducting material loses all the pinning ability and therefore is in the flux-flow regime. In some embodiments, a first magnetic field may be used to drive the superconducting material to the critical state and then a second magnetic field may be used to penetrate the superconducting material. When the external field or combination of external fields are removed, the magnetic field that has penetrated into the material remains trapped. The charged superconducting material may be used as solenoidal magnets, dipole magnets, or other higher order multipole magnets in many applications.

A study of the applicability of gallium arsenide and silicon carbide as aerospace sensor materials

NASA Technical Reports Server (NTRS)

Hurley, John S.

1990-01-01

Most of the piezoresistive sensors, to date, are made of silicon and germanium. Unfortunately, such materials are severly restricted in high temperature environments. By comparing the effects of temperature on the impurity concentrations and piezoresistive coefficients of silicon, gallium arsenide, and silicon carbide, it is being determined if gallium arsenide and silicon carbide are better suited materials for piezoresistive sensors in high temperature environments. The results show that the melting point for gallium arsenide prevents it from solely being used in high temperature situations, however, when used in the alloy Al(x)Ga(1-x)As, not only the advantage of the wider energy band gas is obtained, but also the higher desire melting temperature. Silicon carbide, with its wide energy band gap and higher melting temperature suggests promise as a high temperature piezoresistive sensor.

Nuclear fuels for very high temperature applications

NASA Astrophysics Data System (ADS)

Lundberg, L. B.; Hobbins, R. R.

The success of the development of nuclear thermal propulsion devices and thermionic space nuclear power generation systems depends on the successful utilization of nuclear fuel materials at temperatures in the range 2000 to 3500 K. Problems associated with the utilization of uranium bearing fuel materials at these very high temperatures while maintaining them in the solid state for the required operating times are addressed. The critical issues addressed include evaporation, melting, reactor neutron spectrum, high temperature chemical stability, fabrication, fission induced swelling, fission product release, high temperature creep, thermal shock resistance, and fuel density, both mass and fissile atom. Candidate fuel materials for this temperature range are based on UO2 or uranium carbides. Evaporation suppression, such as a sealed cladding, is required for either fuel base. Nuclear performance data needed for design are sparse for all candidate fuel forms in this temperature range, especially at the higher temperatures.

Experimental study of the thermal stability of materials in high temperature oxygen-containing media

NASA Technical Reports Server (NTRS)

Abaltusov, Y. Y.; Bagramyan, A. R.; Grishin, A. M.; Yukhvid, V. I.

1986-01-01

An experimental study is made of the interaction of several materials with a high temperature medium containing oxygen. The temperature of the surface was measured as a function of time. It is found that the higher the velocity of mass removal from the surface, the more effective is the material from the viewpoint of heat resistance.

High-temperature elastic-plastic and creep properties for SA533 Grade B Class I and SA508 materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, G.B.; Ayres, D.J.

1982-12-01

High temperature elastic-plastic and creep properties are presented for SA533 Grade B Class I and SA508 Class II materials. These properties are derived from tests conducted at Combustion Engineering Material and Metallurgical Laboratories and cover the temperature range of 70/sup 0/F to 1200/sup 0/F.

High temperature XRD of Cu2.1Zn0.9SnSe4

NASA Astrophysics Data System (ADS)

Chetty, Raju; Mallik, Ramesh Chandra

2014-04-01

Quaternary compound with chemical composition Cu2.1Zn0.9SnSe4 is prepared by solid state synthesis. High temperature XRD (X-Ray Diffraction) of this compound is used in studying the effect of temperature on lattice parameters and thermal expansion coefficients. Thermal expansion coefficient is one of the important quantities in evaluating the Grüneisen parameter which further useful in determining the lattice thermal conductivity of the material. The high temperature XRD of the material revealed that the lattice parameters as well as thermal expansion coefficients of the material increased with increase in temperature which confirms the presence of anharmonicty.

Synthesis and design of silicide intermetallic materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrovic, J.J.; Castro, R.G.; Butt, D.P.

1997-04-01

The overall objective of this program is to develop structural silicide-based materials with optimum combinations of elevated temperature strength/creep resistance, low temperature fracture toughness, and high temperature oxidation and corrosion resistance for applications of importance to the U.S. processing industry. A further objective is to develop silicide-based prototype industrial components. The ultimate aim of the program is to work with industry to transfer the structural silicide materials technology to the private sector in order to promote international competitiveness in the area of advanced high temperature materials and important applications in major energy-intensive U.S. processing industries. The program presently has amore » number of developing industrial connections, including a CRADA with Schuller International Inc. targeted at the area of MoSi{sub 2}-based high temperature materials and components for fiberglass melting and processing applications. The authors are also developing an interaction with the Institute of Gas Technology (IGT) to develop silicides for high temperature radiant gas burner applications, for the glass and other industries. Current experimental emphasis is on the development and characterization of MoSi{sub 2}-Si{sub 3}N{sub 4} and MoSi{sub 2}-SiC composites, the plasma spraying of MoSi{sub 2}-based materials, and the joining of MoSi{sub 2} materials to metals.« less

Derivation and test of elevated temperature thermal-stress-free fastener concept

NASA Technical Reports Server (NTRS)

Sawyer, J. W.; Blosser, M. L.; Mcwithey, R. R.

1985-01-01

Future aerospace vehicles must withstand high temperatures and be able to function over a wide temperature range. New composite materials are being developed for use in designing high-temperature lightweight structures. Due to the difference between coefficients of thermal expansion for the new composite materials and conventional high-temperature metallic fasteners, innovative joining techniques are needed to produce tight joints at all temperatures without excessive thermal stresses. A thermal-stress-free fastening technique is presented that can be used to provide structurally tight joints at all temperatures even when the fastener and joined materials have different coefficients of thermal expansion. The derivation of thermal-stress-free fasteners and joint shapes is presented for a wide variety of fastener materials and materials being joined together. Approximations to the thermal-stress-free shapes that result in joints with low-thermal-stresses and that simplify the fastener/joint shape are discussed. The low-thermal-stress fastener concept is verified by thermal and shear tests in joints using oxide-dispersion-strengthened alloy fasteners in carbon-carbon material. The test results show no evidence of thermal stress damage for temperatures up to 2000 F and the resulting joints carried shear loads at room temperature typical of those for conventional joints.

Sealing Materials for Use in Vacuum at High Temperatures

NASA Technical Reports Server (NTRS)

Pettit, Donald R.; Camarda, Charles J.; Lee Vaughn, Wallace

2012-01-01

Sealing materials that can be applied and left in place in vacuum over a wide range of temperatures (especially temperatures of a few thousand degrees Celsius) have been conceived and investigated for potential utility in repairing thermal-protection tiles on the space shuttles in orbit before returning to Earth. These materials are also adaptable to numerous terrestrial applications that involve vacuum processing and/or repair of structures that must withstand high temperatures. These materials can be formulated to have mechanical handling characteristics ranging from almost freely flowing liquid-like consistency through paste-like consistency to stiff puttylike consistency, and to retain these characteristics in vacuum until heated to high curing temperatures. A sealing material of this type can be formulated to be used in any of several different ways for example, to be impregnated into a high-temperature-fabric patch, impregnated into a high-temperature-fabric gasket for sealing a patch, applied under a patch, or applied alone in the manner of putty or wallboard compound. The sealing material must be formulated to be compatible with, and adhere to, the structural material(s) to be repaired. In general, the material consists of a vacuum-compatible liquid containing one or more dissolved compound(s) and/or mixed with suspended solid particles. Depending on the intended application, the liquid can be chosen to be of a compound that can remain in place in vacuum for a time long enough to be useful, and/or to evaporate or decompose in a controlled way to leave a useful solid residue behind. The evaporation rate is determined by proper choice of vapor pressure, application of heat, and/or application of ultraviolet light or other optical radiation. The liquid chosen for the original space shuttle application is a commercial silicone vacuum-pump oil.

NiF2/NaF:CaF2/Ca Solid-State High-Temperature Battery Cells

NASA Technical Reports Server (NTRS)

West, William; Whitacre, Jay; DelCastillo, Linda

2009-01-01

Experiments and theoretical study have demonstrated the promise of all-solid-state, high-temperature electrochemical battery cells based on NiF2 as the active cathode material, CaF2 doped with NaF as the electrolyte material, and Ca as the active anode material. These and other all-solid-state cells have been investigated in a continuing effort to develop batteries for instruments that must operate in environments much hotter than can be withstood by ordinary commercially available batteries. Batteries of this type are needed for exploration of Venus (where the mean surface temperature is about 450 C), and could be used on Earth for such applications as measuring physical and chemical conditions in geothermal wells and oil wells. All-solid-state high-temperature power cells are sought as alternatives to other high-temperature power cells based, variously, on molten anodes and cathodes or molten eutectic salt electrolytes. Among the all-solid-state predecessors of the present NiF2/NaF:CaF2/Ca cells are those described in "Solid-State High-Temperature Power Cells" (NPO-44396), NASA Tech Briefs, Vol. 32, No. 5 (May 2008), page 40. In those cells, the active cathode material is FeS2, the electrolyte material is a crystalline solid solution of equimolar amounts of Li3PO4 and LiSiO4, and the active anode material is Li contained within an alloy that remains solid in the intended high operational temperature range.

Development of aircraft brake materials. [evaluation of metal and ceramic materials in sliding tests simulation of aircraft braking

NASA Technical Reports Server (NTRS)

Ho, T. L.; Peterson, M. B.

1974-01-01

The requirements of brake materials were outlined and a survey made to select materials to meet the needs of high temperature brakes. A number of metals and ceramic materials were selected and evaluated in sliding tests which simulated aircraft braking. Nickel, molybdenum tungsten, Zr02, high temperature cements and carbons were tested. Additives were then incorporated into these materials to optimize their wear or strength behavior with particular emphasis on nickel and molybdenum base materials and a high temperature potassium silicate cement. Optimum materials were developed which improved wear behavior over conventional brake materials in the simulated test. The best materials are a nickel, aluminum oxide, lead tungstate composition containing graphite or molybdenum disulphite; a molybdenum base material containing LPA100 (an intermetallic compound of cobalt, molybdenum, and silicon); and a carbon material (P5).

High-Temperature Modal Survey of a Hot-Structure Control Surface

NASA Technical Reports Server (NTRS)

Spivey, Natalie Dawn

2010-01-01

Ground vibration tests or modal surveys are routinely conducted for supporting flutter analysis for subsonic and supersonic vehicles; however, for hypersonic vehicle applications, thermoelastic vibration testing techniques are not well established and are not routinely performed for supporting hypersonic flutter analysis. New high-temperature material systems, fabrication technologies and high-temperature sensors expand the opportunities to develop advanced techniques for performing ground vibration tests at elevated temperatures. High-temperature materials have the unique property of increasing in stiffness when heated. When these materials are incorporated into a hot-structure, which includes metallic components that decrease in stiffness with increasing temperature, the interaction between the two materials systems needs to be understood because that interaction could ultimately affect the hypersonic flutter analysis. Performing a high-temperature modal survey will expand the research database for hypersonics and will help build upon the understanding of the dual material interaction. This paper will discuss the vibration testing of the Carbon-Silicon Carbide Ruddervator Subcomponent Test Article which is a truncated version of the full-scale X-37 hot-structure control surface. In order to define the modal characteristics of the test article during the elevated-temperature modal survey, two series of room-temperature modal test configurations had to be performed. The room-temperature test series included one with the test article suspended from a bungee cord (free-free) and the second with it mounted on the strongback (fixed boundary condition) in NASA Dryden's Flight Loads Lab large nitrogen test chamber.

The Cutting Edge of High-Temperature Composites

NASA Technical Reports Server (NTRS)

2006-01-01

NASA s Ultra-Efficient Engine Technology (UEET) program was formed in 1999 at Glenn Research Center to manage an important national propulsion program for the Space Agency. The UEET program s focus is on developing innovative technologies to enable intelligent, environmentally friendly, and clean-burning turbine engines capable of reducing harmful emissions while maintaining high performance and increasing reliability. Seven technology projects exist under the program, with each project working towards specific goals to provide new technology for propulsion. One of these projects, Materials and Structures for High Performance, is concentrating on developing and demonstrating advanced high-temperature materials to enable high-performance, high-efficiency, and environmentally compatible propulsion systems. Materials include ceramic matrix composite (CMC) combustor liners and turbine vanes, disk alloys, turbine airfoil material systems, high-temperature polymer matrix composites, and lightweight materials for static engine structures.

The Development of HfO2-Rare Earth Based Oxide Materials and Barrier Coatings for Thermal Protection Systems

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Harder, Bryan James

2014-01-01

Advanced hafnia-rare earth oxides, rare earth aluminates and silicates have been developed for thermal environmental barrier systems for aerospace propulsion engine and thermal protection applications. The high temperature stability, low thermal conductivity, excellent oxidation resistance and mechanical properties of these oxide material systems make them attractive and potentially viable for thermal protection systems. This paper will focus on the development of the high performance and high temperature capable ZrO2HfO2-rare earth based alloy and compound oxide materials, processed as protective coating systems using state-or-the-art processing techniques. The emphasis has been in particular placed on assessing their temperature capability, stability and suitability for advanced space vehicle entry thermal protection systems. Fundamental thermophysical and thermomechanical properties of the material systems have been investigated at high temperatures. Laser high-heat-flux testing has also been developed to validate the material systems, and demonstrating durability under space entry high heat flux conditions.

Advances in High Temperature Materials for Additive Manufacturing

NASA Astrophysics Data System (ADS)

Nordin, Nurul Amira Binti; Johar, Muhammad Akmal Bin; Ibrahim, Mohd Halim Irwan Bin; Marwah, Omar Mohd Faizan bin

2017-08-01

In today’s technology, additive manufacturing has evolved over the year that commonly known as 3D printing. Currently, additive manufacturing have been applied for many industries such as for automotive, aerospace, medical and other commercial product. The technologies are supported by materials for the manufacturing process to produce high quality product. Plus, additive manufacturing technologies has been growth from the lowest to moderate and high technology to fulfil manufacturing industries obligation. Initially from simple 3D printing such as fused deposition modelling (FDM), poly-jet, inkjet printing, to selective laser sintering (SLS), and electron beam melting (EBM). However, the high technology of additive manufacturing nowadays really needs high investment to carry out the process for fine products. There are three foremost type of material which is polymer, metal and ceramic used for additive manufacturing application, and mostly they were in the form of wire feedstock or powder. In circumstance, it is crucial to recognize the characteristics of each type of materials used in order to understand the behaviours of the materials on high temperature application via additive manufacturing. Therefore, this review aims to provide excessive inquiry and gather the necessary information for further research on additive material materials for high temperature application. This paper also proposed a new material based on powder glass, which comes from recycled tempered glass from automotive industry, having a huge potential to be applied for high temperature application. The technique proposed for additive manufacturing will minimize some cost of modelling with same quality of products compare to the others advanced technology used for high temperature application.

Method for charging a hydrogen getter

DOEpatents

Tracy, C. Edwin; Keyser, Matthew A.; Benson, David K.

1998-01-01

A method for charging a sample of either a permanent or reversible getter material with a high concentration of hydrogen while maintaining a base pressure below 10.sup.-4 torr at room temperature involves placing the sample of hydrogen getter material in a chamber, activating the sample of hydrogen getter material, overcharging the sample of getter material through conventional charging techniques to a high concentration of hydrogen, and then subjecting the sample of getter material to a low temperature vacuum bake-out process. Application of the method results in a reversible hydrogen getter which is highly charged to maximum capacities of hydrogen and which concurrently exhibits minimum hydrogen vapor pressures at room temperatures.

Processing Techniques Developed to Fabricate Lanthanum Titanate Piezoceramic Material for High-Temperature Smart Structures

NASA Technical Reports Server (NTRS)

Goldsby, Jon C.; Farmer, Serene C.; Sayir, Ali

2004-01-01

Piezoelectric ceramic materials are potential candidates for use as actuators and sensors in intelligent gas turbine engines. For piezoceramics to be applied in gas turbine engines, they will have to be able to function in temperatures ranging from 1000 to 2500 F. However, the maximum use temperature for state-of-the-art piezoceramic materials is on the order of 300 to 400 F. Research activities have been initiated to develop high-temperature piezoceramic materials for gas turbine engine applications. Lanthanum titanate has been shown to have high-temperature piezoelectric properties with Curie temperatures of T(sub c) = 1500 C and use temperatures greater than 1000 C. However, the fabrication of lanthanum titanate poses serious challenges because of the very high sintering temperatures required for densification. Two different techniques have been developed at the NASA Glenn Research Center to fabricate dense lanthanum titanate piezoceramic material. In one approach, lower sintering temperatures were achieved by adding yttrium oxide to commercially available lanthanum titanate powder. Addition of only 0.1 mol% yttrium oxide lowered the sintering temperature by as much as 300 C, to just 1100 C, and dense lanthanum titanate was produced by pressure-assisted sintering. The second approach utilized the same commercially available powders but used an innovative sintering approach called differential sintering, which did not require any additive.

A novel technique to control high temperature materials degradation in fossil plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gonzalez-Rodriguez, J.G.; Porcayo-Calderon, J.; Martinez-Villafane, A.

1995-11-01

High temperature corrosion of superheater (SH) and, specially, reheater (RH) is strongly dependent on metal temperature. In this work, a way to continuously monitor the metal temperature of SH or RH, elements developed by the Instituto de Investigaciones Electricas (IIE) is described and the effects of operating parameters on metal temperature are evaluated. Also, the effects the steam-generator design and metal temperature on the corrosion rates have been investigated. In some steam generators, corrosion rates were reduced from 0.7 to 0.2 mm/y by changing the tube material and reducing the metal temperature. Also, the effect of metal temperature on themore » residual life of a 347H tube in a 158MW steam generator is evaluated. It is concluded that metal temperature is the most important parameter in controlling the high-temperature materials behavior in boiler environments.« less

Barriers to applying advanced high-temperature materials

NASA Astrophysics Data System (ADS)

Premkumar, M. K.

1993-01-01

During the past 25 years, aerospace engineers and material scientists have made significant technical progress toward developing next-generation aircraft. However, while advanced high-temperature materials continue to be developed, the outlook for their future application is uncertain and will depend on the ability of these materials to satisfy a more diverse market.

Ultra-high temperature tensile properties of ODS steel claddings under severe accident conditions

NASA Astrophysics Data System (ADS)

Yano, Y.; Tanno, T.; Oka, H.; Ohtsuka, S.; Inoue, T.; Kato, S.; Furukawa, T.; Uwaba, T.; Kaito, T.; Ukai, S.; Oono, N.; Kimura, A.; Hayashi, S.; Torimaru, T.

2017-04-01

Ultra-high temperature ring tensile tests were performed to investigate the tensile behavior of oxide dispersion strengthened (ODS) steel claddings and wrapper materials under severe accident conditions with temperatures ranging from room temperature to 1400 °C which is close to the melting point of core materials. The experimental results showed that the tensile strength of 9Cr-ODS steel claddings was highest in the core materials at ultra-high temperatures of 900-1200 °C, but there was significant degradation in the tensile strength of 9Cr-ODS steel claddings above 1200 °C. This degradation was attributed to grain boundary sliding deformation with γ/δ transformation, which is associated with reduced ductility. By contrast, the tensile strength of recrystallized 12Cr-ODS and FeCrAl-ODS steel claddings retained its high value above 1200 °C, unlike the other tested materials.

Thermodynamics and Kinetics of Silicate Vaporization

NASA Technical Reports Server (NTRS)

Jacobson, Nathan S.; Costa, Gustavo C. C.

2015-01-01

Silicates are a common class of materials that are often exposed to high temperatures. The behavior of these materials needs to be understood for applications as high temperature coatings in material science as well as the constituents of lava for geological considerations. The vaporization behavior of these materials is an important aspect of their high temperature behavior and it also provides fundamental thermodynamic data. The application of Knudsen effusion mass spectrometry (KEMS) to silicates is discussed. There are several special considerations for silicates. The first is selection of an appropriate cell material, which is either nearly inert or has well-understood interactions with the silicate. The second consideration is proper measurement of the low vapor pressures. This can be circumvented by using a reducing agent to boost the vapor pressure without changing the solid composition or by working at very high temperatures. The third consideration deals with kinetic barriers to vaporization. The measurement of these barriers, as encompassed in a vaporization coefficient, is discussed. Current measured data of rare earth silicates for high temperature coating applications are discussed. In addition, data on magnesium-iron-silicates (olivine) are presented and discussed.

Development of High Temperature Type Vacuum Insulation Panel using Soluble Polyimide and Characteristic Evaluation

NASA Astrophysics Data System (ADS)

Araki, Kuninari; Kamoto, Daigorou; Matsuoka, Shin-Ichi

The utilization is expected from the high-insulated characteristic as a tool for energy saving also in the high temperature insulation fields as in vacuum insulation panels (VIP) in the future. For high temperature, the material composition and process of VIP were reviewed, the SUS foil was adopted as packaging material, and soluble polyimide was developed as the thermo compression bonding material for high temperature VIP at 150°C. To lower the glass-transition temperature (Tg) under 200°C, we elaborated the new soluble polyimide using aliphatic diamine copolymer, and controlled Tg to about 176°C. By making from trial VIP and evaluations, it was possible to be maintain high performance concerning the coefficient of thermal conductivity [λ<0.008 W/(m·K) at 150°C].

Giving Bigger Satellites a Boost

NASA Technical Reports Server (NTRS)

2000-01-01

Ultramet, Inc. has spurred a new process for producing rocket engine thrust chambers, through SBIR funding and the Glenn Research Center. High-temperature oxidation-resistant thruster materials are being produced in order to achieve high-temperature capability without sacrificing reliability. These thruster materials lead to an estimated three-percent improvement in propulsion system performance. To develop this material, Ultramet used a process called chemical vapor deposition (CVD). CVD involves heating precursors for metals, like iridium and rhenium, to temperatures at which they become gaseous. They are then deposited onto a mandrel, or spindle, layer-by-layer to produce high-density, highly resistant materials from the inside out.

Stochastic clustering of material surface under high-heat plasma load

NASA Astrophysics Data System (ADS)

Budaev, Viacheslav P.

2017-11-01

The results of a study of a surface formed by high-temperature plasma loads on various materials such as tungsten, carbon and stainless steel are presented. High-temperature plasma irradiation leads to an inhomogeneous stochastic clustering of the surface with self-similar granularity - fractality on the scale from nanoscale to macroscales. Cauliflower-like structure of tungsten and carbon materials are formed under high heat plasma load in fusion devices. The statistical characteristics of hierarchical granularity and scale invariance are estimated. They differ qualitatively from the roughness of the ordinary Brownian surface, which is possibly due to the universal mechanisms of stochastic clustering of material surface under the influence of high-temperature plasma.

Next-Generation Electrochemical Energy Materials for Intermediate Temperature Molten Oxide Fuel Cells and Ion Transport Molten Oxide Membranes.

PubMed

Belousov, Valery V

2017-02-21

High temperature electrochemical devices such as solid oxide fuel cells (SOFCs) and oxygen separators based on ceramic materials are used for efficient energy conversion. These devices generally operate in the temperature range of 800-1000 °C. The high operating temperatures lead to accelerated degradation of the SOFC and oxygen separator materials. To solve this problem, the operating temperatures of these electrochemical devices must be lowered. However, lowering the temperature is accompanied by decreasing the ionic conductivity of fuel cell electrolyte and oxygen separator membrane. Therefore, there is a need to search for alternative electrolyte and membrane materials that have high ionic conductivity at lower temperatures. A great many opportunities exist for molten oxides as electrochemical energy materials. Because of their unique electrochemical properties, the molten oxide innovations can offer significant benefits for improving energy efficiency. In particular, the newly developed electrochemical molten oxide materials show high ionic conductivities at intermediate temperatures (600-800 °C) and could be used in molten oxide fuel cells (MOFCs) and molten oxide membranes (MOMs). The molten oxide materials containing both solid grains and liquid channels at the grain boundaries have advantages compared to the ceramic materials. For example, the molten oxide materials are ductile, which solves a problem of thermal incompatibility (difference in coefficient of thermal expansion, CTE). Besides, the outstanding oxygen selectivity of MOM materials allows us to separate ultrahigh purity oxygen from air. For their part, the MOFC electrolytes show the highest ionic conductivity at intermediate temperatures. To evaluate the potential of molten oxide materials for technological applications, the relationship between the microstructure of these materials and their transport and mechanical properties must be revealed. This Account summarizes the latest results on oxygen ion transport in potential MOM materials and MOFC electrolytes. In addition, we consider the rapid oxygen transport in a molten oxide scale formed on a metal surface during catastrophic oxidation and show that the same transport could be used beneficially in MOMs and MOFCs. A polymer model explaining the oxygen transport in molten oxides is also considered. Understanding the oxygen transport mechanisms in oxide melts is important for the development of new generation energy materials, which will contribute to more efficient operation of electrochemical devices at intermediate temperatures. Here we highlight the progress made in developing this understanding. We also show the latest advances made in search of alternative molten oxide materials having high mixed ion electronic and ionic conductivities for use in MOMs and MOFCs, respectively. Prospects for further research are presented.

Structural application of high strength, high temperature ceramics

NASA Technical Reports Server (NTRS)

Hall, W. B.

1982-01-01

The operation of rocket engine turbine pumps is limited by the temperature restrictions of metallic components used in the systems. Mechanical strength and stability of these metallic components decrease drastically at elevated temperatures. Ceramic materials that retain high strength at high temperatures appear to be a feasible alternate material for use in the hot end of the turbopumps. This project identified and defined the processing parameters that affected the properties of Si3N4, one of candidate ceramic materials. Apparatus was assembled and put into operation to hot press Si3N4 powders into bulk material for in house evaluation. A work statement was completed to seek outside contract services to design, manufacture, and evaluate Si3N4 components in the service environments that exists in SSME turbopumps.

Encapsulation of High Temperature Phase Change Materials for Thermal Energy Storage

NASA Astrophysics Data System (ADS)

Nath, Rupa

Thermal energy storage is a major contributor to bridge the gap between energy demand (consumption) and energy production (supply) by concentrating solar power. The utilization of high latent heat storage capability of phase change materials is one of the keys to an efficient way to store thermal energy. However, some of the limitations of the existing technology are the high volumetric expansion and low thermal conductivity of phase change materials (PCMs), low energy density, low operation temperatures and high cost. The present work deals with encapsulated PCM system, which operates at temperatures above 500°C and takes advantage of the heat transfer modes at such high temperatures to overcome the aforementioned limitations of PCMs. Encapsulation with sodium silicate coating on preformed PCM pellets were investigated. A low cost, high temperature metal, carbon steel has been used as a capsule for PCMs with a melting point above 500° C. Sodium silicate and high temperature paints were used for oxidation protection of steel at high temperatures. The emissivity of the coatings to enhance heat transfer was investigated.

High temperature experimental characterization of microscale thermoelectric effects

NASA Astrophysics Data System (ADS)

Favaloro, Tela

Thermoelectric devices have been employed for many years as a reliable energy conversion technology for applications ranging from the cooling of sensors or charge coupled devices to the direct conversion of heat into electricity for remote power generation. However, its relatively low conversion efficiency has limited the implementation of thermoelectric materials for large scale cooling and waste heat recovery applications. Recent advances in semiconductor growth technology have enabled the precise and selective engineering of material properties to improve the thermoelectric figure of merit and thus the efficiency of thermoelectric devices. Accurate characterization at the intended operational temperature of novel thermoelectric materials is a crucial component of the optimization process in order to fundamentally understand material behavior and evaluate performance. The objective of this work is to provide the tools necessary to characterize high efficiency bulk and thin-film materials for thermoelectric energy conversion. The techniques developed here are not bound to specific material or devices, but can be generalized to any material system. Thermoreflectance imaging microscopy has proven to be invaluable for device thermometry owing to its high spatial and temporal resolutions. It has been utilized in this work to create two-dimensional temperature profiles of thermoelectric devices during operation used for performance analysis of novel materials, identification of defects, and visualization of high speed transients in a high-temperature imaging thermostat. We report the development of a high temperature imaging thermostat capable of high speed transient thermoelectric characterization. In addition, we present a noninvasive method for thermoreflectance coefficient calibration ideally suited for vacuum and thus high temperature employment. This is the first analysis of the thermoreflectance coefficient of commonly used metals at high-temperatures. High temperature vacuum thermostats are designed and fabricated with optical imaging capability and interchangeable measurement stages for various electrical and thermoelectric characterizations. We demonstrate the simultaneous measurement of in-plane electrical conductivity and Seebeck coefficient of thin-film or bulk thermoelectric materials. Furthermore, we utilize high-speed circuitry to implement the transient Harman technique and directly determine the cross-plane figure of merit of thin film thermoelectric materials at high temperatures. Transient measurements on thin film devices are subject to complications from the growth substrate, non-ideal contacts and other detrimental thermal and electrical effects. A strategy is presented for optimizing device geometry to mitigate the impact of these parasitics. This design enabled us to determine the cross-plane thermoelectric material properties in a single high temperature measurement of a 25mum InGaAs thin film with embedded ErAs (0.2%) nanoparticles using the bipolar transient Harman technique in conjunction with thermoreflectance thermal imaging. This approach eliminates discrepancies and potential device degradation from the multiple measurements necessary to obtain individual material parameters. Finite element method simulations are used to analyze non-uniform current and temperature distributions over the device area and determine the three dimensional current path for accurate extraction of material properties from the thermal images. Results match with independent measurements of thermoelectric material properties for the same material composition, validating this approach. We apply high magnification thermoreflectance imaging to create temperature maps of vanadium dioxide nanobeams and examine electro-thermal energy conversion along the nanobeam length. The metal to insulator transition of strongly correlated materials is subject to strong lattice coupling which brings about the unique one-dimensional alignment of metal-insulator domains along nanobeams. Many studies have investigated the effects of stress on the metal to insulator transition and hence the phase boundary, but few have directly examined the temperature profile across the metal-insulating interface. Here, thermoreflectance microscopy reveals the underlying behavior of single-crystalline VO2 nanobeams in the phase coexisting regime. We directly observe highly localized alternating Peltier heating and cooling as well as Joule heating concentrated at the domain interfaces, indicating the significance of the domain walls and band offsets. Moreover, we are able to elucidate strain accumulation along the nanobeam and distinguish between two insulating phases of VO 2 through detection of the opposite polarity of their respective thermoreflectance coefficients.

Very high temperature chemistry: Science justification for containerless experimentation in space

NASA Technical Reports Server (NTRS)

Hofmeister, William H.; Nordine, Paul

1990-01-01

A summary is presented of the justification for application of containerless processing in space to high temperature science. Low earth orbit offers a gravitational environment that allows samples to be positioned in an experimental apparatus by very small forces. Well controlled experiments become possible on reactive materials at high temperatures in a reasonably quiescent state and without container contamination. This provides an opportunity to advance the science of high temperature chemistry that can only be realized with a commitment by NASA to provide advanced facilities for in-space containerless study of materials at very high temperature.

Cost-Cutting Powdered Lubricant

NASA Technical Reports Server (NTRS)

2005-01-01

Scientists at NASA's Glenn Research Center developed a high-temperature, solid lubricant coating material that is saving the manufacturing industry millions of dollars. The material came out of 3 decades of tribological research, work studying high-temperature friction, lubrication, and the wearing of interacting surfaces that are in relative motion. It was developed as a shaft coating deposited by thermal spraying to protect foil air bearings used in oil-free turbomachinery, like gas turbines, and is meant to be part of a larger project: an oil-free aircraft engine capable of operating at high temperatures with increased reliability, lowered weight, reduced maintenance requirements, and increased power. This advanced coating, PS300, is a self-lubricating bearing material containing chromium oxide, with additions of a low-temperature start up lubricant (silver) and a high-temperature lubricant, making it remarkably stable at high temperatures, and better suited than previously available materials for high-stress conditions. It improves efficiency, lowers friction, reduces emissions, and has been used by NASA in advanced aeropropulsion engines, refrigeration compressors, turbochargers, and hybrid electrical turbogenerators. PS300 is ideal in any application where lowered weight and reduced maintenance are desired, and high-temperature uses and heavy operating speeds are expected. It has notable uses for the Space Agency, but it has even further-reaching potential for the industrial realm.

Pseudo-icosahedral Cr55Al232 -δ as a high-temperature protective material

NASA Astrophysics Data System (ADS)

Rosa, R.; Bhattacharya, S.; Pabla, J.; He, H.; Misuraca, J.; Nakajima, Y.; Bender, A. D.; Antonacci, A. K.; Adrip, W.; McNally, D. E.; Zebro, A.; Kamenov, P.; Geschwind, G.; Ghose, S.; Dooryhee, E.; Ibrahim, A.; Tritt, T. M.; Aronson, M. C.; Simonson, J. W.

2018-03-01

We report here a course of basic research into the potential suitability of a pseudo-icosahedral Cr aluminide as a material for high-temperature protective coatings. Cr55Al232 -δ [ δ =2.70 (6 ) ] exhibits high hardness at room temperature as well as low thermal conductivity and excellent oxidation resistance at 973 K, with an oxidation rate comparable to those of softer, denser benchmark materials. The origin of these promising properties can be traced to competing long-range and short-range symmetries within the pseudo-icosahedral crystal structure, suggesting new criteria for future materials research.

Design of a low-cost system for electrical conductivity measurements of high temperature

NASA Astrophysics Data System (ADS)

Singh, Yadunath

2018-05-01

It is always a curiosity and interest among researchers working in the field of material science to know the impact of high temperature on the physical and transport properties of the materials. In this paper, we report on the design and working of a system for the measurements of electrical resistivity with high temperature. It was designed at our place and successively used for these measurements in the temperature range from room temperature to 500 ˚C.

Dynamic High-temperature Testing of an Iridium Alloy in Compression at High-strain Rates: Dynamic High-temperature Testing

DOE PAGES

Song, B.; Nelson, K.; Lipinski, R.; ...

2014-08-21

Iridium alloys have superior strength and ductility at elevated temperatures, making them useful as structural materials for certain high-temperature applications. However, experimental data on their high-strain -rate performance are needed for understanding high-speed impacts in severe environments. Kolsky bars (also called split Hopkinson bars) have been extensively employed for high-strain -rate characterization of materials at room temperature, but it has been challenging to adapt them for the measurement of dynamic properties at high temperatures. In our study, we analyzed the difficulties encountered in high-temperature Kolsky bar testing of thin iridium alloy specimens in compression. We made appropriate modifications using themore » current high-temperature Kolsky bar technique in order to obtain reliable compressive stress–strain response of an iridium alloy at high-strain rates (300–10 000 s -1) and temperatures (750 and 1030°C). The compressive stress–strain response of the iridium alloy showed significant sensitivity to both strain rate and temperature.« less

Manganese mono-boride, an inexpensive room temperature ferromagnetic hard material

PubMed Central

Ma, Shuailing; Bao, Kuo; Tao, Qiang; Zhu, Pinwen; Ma, Teng; Liu, Bo; Liu, Yazhou; Cui, Tian

2017-01-01

We synthesized orthorhombic FeB-type MnB (space group: Pnma) with high pressure and high temperature method. MnB is a promising soft magnetic material, which is ferromagnetic with Curie temperature as high as 546.3 K, and high magnetization value up to 155.5 emu/g, and comparatively low coercive field. The strong room temperature ferromagnetic properties stem from the positive exchange-correlation between manganese atoms and the large number of unpaired Mn 3d electrons. The asymptotic Vickers hardness (AVH) is 15.7 GPa which is far higher than that of traditional ferromagnetic materials. The high hardness is ascribed to the zigzag boron chains running through manganese lattice, as unraveled by X-ray photoelectron spectroscopy result and first principle calculations. This exploration opens a new class of materials with the integration of superior mechanical properties, lower cost, electrical conductivity, and fantastic soft magnetic properties which will be significant for scientific research and industrial application as advanced structural and functional materials. PMID:28262805

Characterizing the Chemical Stability of High Temperature Materials for Application in Extreme Environments

NASA Technical Reports Server (NTRS)

Opila, Elizabeth

2005-01-01

The chemical stability of high temperature materials must be known for use in the extreme environments of combustion applications. The characterization techniques available at NASA Glenn Research Center vary from fundamental thermodynamic property determination to material durability testing in actual engine environments. In this paper some of the unique techniques and facilities available at NASA Glenn will be reviewed. Multiple cell Knudsen effusion mass spectrometry is used to determine thermodynamic data by sampling gas species formed by reaction or equilibration in a Knudsen cell held in a vacuum. The transpiration technique can also be used to determine thermodynamic data of volatile species but at atmospheric pressures. Thermodynamic data in the Si-O-H(g) system were determined with this technique. Free Jet Sampling Mass Spectrometry can be used to study gas-solid interactions at a pressure of one atmosphere. Volatile Si(OH)4(g) was identified by this mass spectrometry technique. A High Pressure Burner Rig is used to expose high temperature materials in hydrocarbon-fueled combustion environments. Silicon carbide (SiC) volatility rates were measured in the burner rig as a function of total pressure, gas velocity and temperature. Finally, the Research Combustion Lab Rocket Test Cell is used to expose high temperature materials in hydrogen/oxygen rocket engine environments to assess material durability. SiC recession due to rocket engine exposures was measured as a function of oxidant/fuel ratio, temperature, and total pressure. The emphasis of the discussion for all techniques will be placed on experimental factors that must be controlled for accurate acquisition of results and reliable prediction of high temperature material chemical stability.

High temperature XRD of Cu{sub 2.1}Zn{sub 0.9}SnSe{sub 4}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chetty, Raju, E-mail: rcmallik@physics.iisc.ernet.in; Mallik, Ramesh Chandra, E-mail: rcmallik@physics.iisc.ernet.in

2014-04-24

Quaternary compound with chemical composition Cu{sub 2.1}Zn{sub 0.9}SnSe{sub 4} is prepared by solid state synthesis. High temperature XRD (X-Ray Diffraction) of this compound is used in studying the effect of temperature on lattice parameters and thermal expansion coefficients. Thermal expansion coefficient is one of the important quantities in evaluating the Grüneisen parameter which further useful in determining the lattice thermal conductivity of the material. The high temperature XRD of the material revealed that the lattice parameters as well as thermal expansion coefficients of the material increased with increase in temperature which confirms the presence of anharmonicty.

Mechanical characterization of alloys in extreme conditions of high strain rates and high temperature

NASA Astrophysics Data System (ADS)

Cadoni, Ezio

2018-03-01

The aim of this paper is the description of the mechanical characterization of alloys under extreme conditions of temperature and loading. In fact, in the frame of the Cost Action CA15102 “Solutions for Critical Raw Materials Under Extreme Conditions (CRM-EXTREME)” this aspect is crucial and many industrial applications have to consider the dynamic response of materials. Indeed, for a reduction and substitution of CRMs in alloys is necessary to design the materials and understand if the new materials behave better or if the substitution or reduction badly affect their performance. For this reason, a deep knowledge of the mechanical behaviour at high strain-rates of considered materials is required. In general, machinery manufacturing industry or transport industry as well as energy industry have important dynamic phenomena that are simultaneously affected by extended strain, high strain-rate, damage and pressure, as well as conspicuous temperature gradients. The experimental results in extreme conditions of high strain rate and high temperature of an austenitic stainless steel as well as a high-chromium tempered martensitic reduced activation steel Eurofer97 are presented.

Report on the Installation and Preparedness of a Protochips Fusion in-situ Heating Holder for TEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edmondson, Philip D.

2017-03-01

This brief report documents the procurement and installation of a Protochips Fusion (formerly Aduro) high-temperature, high stability transmission electron microscopy (TEM) specimen holder that allows for the high spatial resolution characterization of material specimens at high temperature in situ of an electron microscope. This specimen holder was specifically procured for use with The FEI Talos F200X Scanning/Transmission Electron Microscope (STEM) in Oak Ridge National Laboratory’s (ORNL’s) Low Activation Materials Development and Analysis (LAMDA) Laboratory. The Protochips Fusion holder will enable high-resolution structural and chemical analysis of irradiated materials at high temperature, becoming a unique capability worldwide, and would encourage high-qualitymore » in situ experiments to be conducted on irradiated materials.« less

High temperature pressure coupled ultrasonic waveguide

DOEpatents

Caines, Michael J.

1983-01-01

A pressure coupled ultrasonic waveguide is provided to which one end may be attached a transducer and at the other end a high temperature material for continuous ultrasonic testing of the material. The ultrasonic signal is coupled from the waveguide into the material through a thin, dry copper foil.

High-temperature pressure-coupled ultrasonic waveguide

DOEpatents

Caines, M.J.

1981-02-11

A pressure coupled ultrasonic waveguide is provided to which one end may be attached a transducer and at the other end a high temperature material for continuous ultrasonic testing of the material. The ultrasonic signal is coupled from the waveguide into the material through a thin, dry copper foil.

High-temperature durability considerations for HSCT combustor

NASA Technical Reports Server (NTRS)

Jacobson, Nathan S.

1992-01-01

The novel combustor designs for the High Speed Civil Transport will require high temperature materials with long term environmental stability. Higher liner temperatures than in conventional combustors and the need for reduced weight necessitates the use of advanced ceramic matrix composites. The combustor environment is defined at the current state of design, the major degradation routes are discussed for each candidate ceramic material, and where possible, the maximum use temperatures are defined for these candidate ceramics.

Determining the tensile response of materials at high temperature using DIC and the Virtual Fields Method

NASA Astrophysics Data System (ADS)

Valeri, Guillermo; Koohbor, Behrad; Kidane, Addis; Sutton, Michael A.

2017-04-01

An experimental approach based on Digital Image Correlation (DIC) is successfully applied to predict the uniaxial stress-strain response of 304 stainless steel specimens subjected to nominally uniform temperatures ranging from room temperature to 900 °C. A portable induction heating device equipped with custom made water-cooled copper coils is used to heat the specimen. The induction heater is used in conjunction with a conventional tensile frame to enable high temperature tension experiments. A stereovision camera system equipped with appropriate band pass filters is employed to facilitate the study of full-field deformation response of the material at elevated temperatures. Using the temperature and load histories along with the full-field strain data, a Virtual Fields Method (VFM) based approach is implemented to identify constitutive parameters governing the plastic deformation of the material at high temperature conditions. Results from these experiments confirm that the proposed method can be used to measure the full field deformation of materials subjected to thermo-mechanical loading.

An Insertable Passive LC Pressure Sensor Based on an Alumina Ceramic for In Situ Pressure Sensing in High-Temperature Environments.

PubMed

Xiong, Jijun; Li, Chen; Jia, Pinggang; Chen, Xiaoyong; Zhang, Wendong; Liu, Jun; Xue, Chenyang; Tan, Qiulin

2015-08-31

Pressure measurements in high-temperature applications, including compressors, turbines, and others, have become increasingly critical. This paper proposes an implantable passive LC pressure sensor based on an alumina ceramic material for in situ pressure sensing in high-temperature environments. The inductance and capacitance elements of the sensor were designed independently and separated by a thermally insulating material, which is conducive to reducing the influence of the temperature on the inductance element and improving the quality factor of the sensor. In addition, the sensor was fabricated using thick film integrated technology from high-temperature materials that ensure stable operation of the sensor in high-temperature environments. Experimental results showed that the sensor accurately monitored pressures from 0 bar to 2 bar at temperatures up to 800 °C. The sensitivity, linearity, repeatability error, and hysteretic error of the sensor were 0.225 MHz/bar, 95.3%, 5.5%, and 6.2%, respectively.

An Insertable Passive LC Pressure Sensor Based on an Alumina Ceramic for In Situ Pressure Sensing in High-Temperature Environments

PubMed Central

Xiong, Jijun; Li, Chen; Jia, Pinggang; Chen, Xiaoyong; Zhang, Wendong; Liu, Jun; Xue, Chenyang; Tan, Qiulin

2015-01-01

Pressure measurements in high-temperature applications, including compressors, turbines, and others, have become increasingly critical. This paper proposes an implantable passive LC pressure sensor based on an alumina ceramic material for in situ pressure sensing in high-temperature environments. The inductance and capacitance elements of the sensor were designed independently and separated by a thermally insulating material, which is conducive to reducing the influence of the temperature on the inductance element and improving the quality factor of the sensor. In addition, the sensor was fabricated using thick film integrated technology from high-temperature materials that ensure stable operation of the sensor in high-temperature environments. Experimental results showed that the sensor accurately monitored pressures from 0 bar to 2 bar at temperatures up to 800 °C. The sensitivity, linearity, repeatability error, and hysteretic error of the sensor were 0.225 MHz/bar, 95.3%, 5.5%, and 6.2%, respectively. PMID:26334279

Beta-manganese dioxide nanorods for sufficient high-temperature electromagnetic interference shielding in X-band

NASA Astrophysics Data System (ADS)

Song, Wei-Li; Cao, Mao-Sheng; Hou, Zhi-Ling; Lu, Ming-Ming; Wang, Chan-Yuan; Yuan, Jie; Fan, Li-Zhen

2014-09-01

As the development of electronic and communication technology, electromagnetic interference (EMI) shielding and attenuation is an effective strategy to ensure the operation of the electronic devices. Among the materials for high-performance shielding in aerospace industry and related high-temperature working environment, the thermally stable metal oxide semiconductors with narrow band gap are promising candidates. In this work, beta-manganese dioxide ( β-MnO2) nanorods were synthesized by a hydrothermal method. The bulk materials of the β-MnO2 were fabricated to evaluate the EMI shielding performance in the temperature range of 20-500 °C between 8.2 and 12.4 GHz (X-band). To understand the mechanisms of high-temperature EMI shielding, the contribution of reflection and absorption to EMI shielding was discussed based on temperature-dependent electrical properties and complex permittivity. Highly sufficient shielding effectiveness greater than 20 dB was observed over all the investigated range, suggesting β-MnO2 nanorods as promising candidates for high-temperature EMI shielding. The results have also established a platform to develop high-temperature EMI shielding materials based on nanoscale semiconductors.

Radiation and temperature effects on electronic components investigated under the CSTI high capacity power project

NASA Technical Reports Server (NTRS)

Schwarze, Gene E.; Niedra, Janis M.; Frasca, Albert J.; Wieserman, William R.

1993-01-01

The effects of nuclear radiation and high temperature environments must be fully known and understood for the electronic components and materials used in both the Power Conditioning and Control subsystem and the reactor Instrumentation and Control subsystem of future high capacity nuclear space power systems. This knowledge is required by the designer of these subsystems in order to develop highly reliable, long-life power systems for future NASA missions. A review and summary of the experimental results obtained for the electronic components and materials investigated under the power management element of the Civilian Space Technology Initiative (CSTI) high capacity power project are presented: (1) neutron, gamma ray, and temperature effects on power semiconductor switches, (2) temperature and frequency effects on soft magnetic materials; and (3) temperature effects on rare earth permanent magnets.

Method for charging a hydrogen getter

DOEpatents

Tracy, C.E.; Keyser, M.A.; Benson, D.K.

1998-09-15

A method for charging a sample of either a permanent or reversible getter material with a high concentration of hydrogen while maintaining a base pressure below 10{sup {minus}4} torr at room temperature involves placing the sample of hydrogen getter material in a chamber, activating the sample of hydrogen getter material, overcharging the sample of getter material through conventional charging techniques to a high concentration of hydrogen, and then subjecting the sample of getter material to a low temperature vacuum bake-out process. Application of the method results in a reversible hydrogen getter which is highly charged to maximum capacities of hydrogen and which concurrently exhibits minimum hydrogen vapor pressures at room temperatures. 9 figs.

Development of Processing Techniques for Advanced Thermal Protection Materials

NASA Technical Reports Server (NTRS)

Selvaduray, Guna; Lacson, Jamie; Collazo, Julian

1997-01-01

During the period June 1, 1996 through May 31, 1997, the main effort has been in the development of materials for high temperature applications. Thermal Protection Systems (TPS) are constantly being tested and evaluated for thermal shock resistance, high temperature dimensional stability, and tolerance to environmental effects. Materials development was carried out by using many different instruments and methods, ranging from intensive elemental analysis to testing the physical attributes of a material. The material development concentrated on two key areas: (1) development of coatings for carbon/carbon composites, and (2) development of ultra-high temperature ceramics (UHTC). This report describes the progress made in these two areas of research during this contract period.

Evaluation and ranking of candidate ceramic wafer engine seal materials

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.

1991-01-01

Modern engineered ceramics offer high temperature capabilities not found in even the best superalloy metals. The high temperature properties of several selected ceramics including aluminum oxide, silicon carbide, and silicon nitride are reviewed as they apply to hypersonic engine seal design. A ranking procedure is employed to objectively differentiate among four different monolithic ceramic materials considered, including: a cold-pressed and sintered aluminum oxide; a sintered alpha-phase silicon carbide; a hot-isostatically pressed silicon nitride; and a cold-pressed and sintered silicon nitride. This procedure is used to narrow the wide range of potential ceramics considered to an acceptable number for future detailed and costly analyses and tests. The materials are numerically scored according to their high temperature flexural strength; high temperature thermal conductivity; resistance to crack growth; resistance to high heating rates; fracture toughness; Weibull modulus; and finally according to their resistance to leakage flow, where materials having coefficients of thermal expansion closely matching the engine panel material resist leakage flow best. The cold-pressed and sintered material (Kyocera SN-251) ranked the highest in the overall ranking especially when implemented in engine panels made of low expansion rate materials being considered for the engine, including Incoloy and titanium alloys.

Non-graphite crucible for high temperature applications

DOEpatents

Holcombe, C.E.; Pfeiler, W.A.

1994-08-02

A multi-piece crucible for high temperature applications comprises a tubular side wall member having a lip on the inside surface and a bottom member or members forming a container for containing a melt of a material during a high temperature melt-casting operations. The multi-piece design prevents cracking of the crucible or leakage of the melt from the crucible during the melt-casting operation. The lip of the tubular member supports the bottom member. The contacting surfaces where the lip of the tubular side wall member contacts the bottom member of the multi-piece crucible contains a ceramic sealing material. The ceramic sealing material forms a seal sufficient to prevent the melt of the material from leaking out of the multi-piece crucible during the melt-casting process. The multi-piece crucible is made of a material which is chemically inert to the melt and has structural integrity at the melting point temperature of the melt, or of a material coated with such a material. 6 figs.

Non-graphite crucible for high temperature applications

DOEpatents

Holcombe, Cressie E.; Pfeiler, William A.

1994-01-01

A multi-piece crucible for high temperature applications comprises a tubular side wall member having a lip on the inside surface and a bottom member or members forming a container for containing a melt of a material during a high temperature melt-casting operations. The multi-piece design prevents cracking of the crucible or leakage of the melt from the crucible during the melt-casting operation. The lip of the tubular member supports the bottom member. The contacting surfaces where the lip of the tubular side wall member contacts the bottom member of the multi-piece crucible contains a ceramic sealing material. The ceramic sealing material forms a seal sufficient to prevent the melt of the material from leaking out of the multi-piece crucible during the melt-casting process. The multi-piece crucible is made of a material which is chemically inert to the melt and has structural integrity at the melting point temperature of the melt, or of a material coated with such a material.

High-Temperature Modal Survey of a Hot-Structure Control Surface

NASA Technical Reports Server (NTRS)

Spivey, Natalie D.

2011-01-01

Ground vibration tests are routinely conducted for supporting flutter analysis for subsonic and supersonic vehicles; however, for hypersonic vehicles, thermoelastic vibration testing techniques are neither well established nor routinely performed. New high-temperature material systems, fabrication technologies and high-temperature sensors expand the opportunities to develop advanced techniques for performing ground vibration tests at elevated temperatures. When high-temperature materials, which increase in stiffness when heated, are incorporated into a hot-structure that contains metallic components that decrease in stiffness when heated, the interaction between those materials can affect the hypersonic flutter analysis. A high-temperature modal survey will expand the research database for hypersonics and improve the understanding of this dual-material interaction. This report discusses the vibration testing of the carbon-silicon carbide Ruddervator Subcomponent Test Article, which is a truncated version of a full-scale hot-structure control surface. Two series of room-temperature modal test configurations were performed in order to define the modal characteristics of the test article during the elevated-temperature modal survey: one with the test article suspended from a bungee cord (free-free) and the second with it mounted on the strongback (fixed boundary). Testing was performed in the NASA Dryden Flight Research Center Flight Loads Laboratory Large Nitrogen Test Chamber.

Surface Fatigue Life of High Temperature Gear Materials

NASA Technical Reports Server (NTRS)

Townsend, Dennis P.

1994-01-01

Three high temperature gear materials were evaluated using spur gear surface fatigue tests. These materials were, VASCO max 350, VASCO matrix 2, and nitralloy N and were evaluated for possible use in high temperature gear applications. The fatigue life of the three high temperature gear materials were compared with the life of the standard AISI 9310 aircraft gear material. Surface fatigue tests were conducted at a lubricant inlet temperature of 321 K (120 F), a lubricant outlet temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), a speed of 10,000 rpm, and with a synthetic paraffinic lubricant. The life of the nitralloy N was approximately the same as the AISI 9310, the life of the VASCO max 350 was much less than the AISI 9310 while the life of the VASCO matrix 2 was several times the life of the AISI 9310. The VASCO max 350 also showed very low fracture toughness with approximately half of the gears failed by tooth fracture through the fatigue spall. The VASCO matrix 2 had approximately 10-percent fracture failure through the fatigue spalls indicating moderate to good fracture toughness.

MoSi2-Base Composite for Engine Applications

NASA Technical Reports Server (NTRS)

Hebsur, Mohan G.; Nathal, Michael V.

1997-01-01

The intermetallic compound MoSi2 has long been known as a high temperature material that has excellent oxidation resistance and electrical/thermal conductivity. Also its low cost, high melting point (2023 C), relatively low density (6.2 g/cm versus 8 g/cm for current engine materials), and ease of machining make it an attractive structural material. However, the use of MoSi2 has been hindered because of the brittle nature of the material at low temperatures, inadequate creep resistance at high temperatures, accelerated oxidation (also known as 'pest' oxidation) at temperatures between approximately 400 and 500 C, and a coefficient of thermal expansion (CTE) that is relatively high in comparison to potential reinforcing fibers such as SiC. This CTE mismatch between the fiber and the matrix resulted in severe matrix cracking during thermal cycling.

Water-Based Coating Simplifies Circuit Board Manufacturing

NASA Technical Reports Server (NTRS)

2008-01-01

The Structures and Materials Division at Glenn Research Center is devoted to developing advanced, high-temperature materials and processes for future aerospace propulsion and power generation systems. The Polymers Branch falls under this division, and it is involved in the development of high-performance materials, including polymers for high-temperature polymer matrix composites; nanocomposites for both high- and low-temperature applications; durable aerogels; purification and functionalization of carbon nanotubes and their use in composites; computational modeling of materials and biological systems and processes; and developing polymer-derived molecular sensors. Essentially, this branch creates high-performance materials to reduce the weight and boost performance of components for space missions and aircraft engine components. Under the leadership of chemical engineer, Dr. Michael Meador, the Polymers Branch boasts world-class laboratories, composite manufacturing facilities, testing stations, and some of the best scientists in the field.

Investigation of Tokamak Solid Divertor Target Options.

DTIC Science & Technology

1981-05-26

but materials are not known which could operate at the high resulting wall temperatures . Mist- steam flows would also demand a relatively high ...flux P = coolant density = bulk coolant viscosity w = coolant viscosity at average wall temperature = units conversion At high heat loads and moderate...therefore, the inner wall temperature will be over 300 OF, posing a high temp- erature materials challenge. E. Swirl and Mixed Flow Schemes Extensive work

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, B.; Nelson, K.; Lipinski, R.

Iridium alloys have superior strength and ductility at elevated temperatures, making them useful as structural materials for certain high-temperature applications. However, experimental data on their high-strain -rate performance are needed for understanding high-speed impacts in severe environments. Kolsky bars (also called split Hopkinson bars) have been extensively employed for high-strain -rate characterization of materials at room temperature, but it has been challenging to adapt them for the measurement of dynamic properties at high temperatures. In our study, we analyzed the difficulties encountered in high-temperature Kolsky bar testing of thin iridium alloy specimens in compression. We made appropriate modifications using themore » current high-temperature Kolsky bar technique in order to obtain reliable compressive stress–strain response of an iridium alloy at high-strain rates (300–10 000 s -1) and temperatures (750 and 1030°C). The compressive stress–strain response of the iridium alloy showed significant sensitivity to both strain rate and temperature.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Bo; Nelson, Kevin; Lipinski, Ronald J.

Iridium alloys have superior strength and ductility at elevated temperatures, making them useful as structural materials for certain high-temperature applications. However, experimental data on their high-temperature high-strain-rate performance are needed for understanding high-speed impacts in severe elevated-temperature environments. Kolsky bars (also called split Hopkinson bars) have been extensively employed for high-strain-rate characterization of materials at room temperature, but it has been challenging to adapt them for the measurement of dynamic properties at high temperatures. Current high-temperature Kolsky compression bar techniques are not capable of obtaining satisfactory high-temperature high-strain-rate stress-strain response of thin iridium specimens investigated in this study. We analyzedmore » the difficulties encountered in high-temperature Kolsky compression bar testing of thin iridium alloy specimens. Appropriate modifications were made to the current high-temperature Kolsky compression bar technique to obtain reliable compressive stress-strain response of an iridium alloy at high strain rates (300 – 10000 s -1) and temperatures (750°C and 1030°C). Uncertainties in such high-temperature high-strain-rate experiments on thin iridium specimens were also analyzed. The compressive stress-strain response of the iridium alloy showed significant sensitivity to strain rate and temperature.« less

Solid-solid phase change thermal storage application to space-suit battery pack

NASA Astrophysics Data System (ADS)

Son, Chang H.; Morehouse, Jeffrey H.

1989-01-01

High cell temperatures are seen as the primary safety problem in the Li-BCX space battery. The exothermic heat from the chemical reactions could raise the temperature of the lithium electrode above the melting temperature. Also, high temperature causes the cell efficiency to decrease. Solid-solid phase-change materials were used as a thermal storage medium to lower this battery cell temperature by utilizing their phase-change (latent heat storage) characteristics. Solid-solid phase-change materials focused on in this study are neopentyl glycol and pentaglycerine. Because of their favorable phase-change characteristics, these materials appear appropriate for space-suit battery pack use. The results of testing various materials are reported as thermophysical property values, and the space-suit battery operating temperature is discussed in terms of these property results.

All-optical technique for measuring thermal properties of materials at static high pressure

NASA Astrophysics Data System (ADS)

Pangilinan, G. I.; Ladouceur, H. D.; Russell, T. P.

2000-10-01

The development and implementation of an all-optical technique for measuring thermal transport properties of materials at high pressure in a gem anvil cell are reported. Thermal transport properties are determined by propagating a thermal wave in a material subjected to high pressures, and measuring the temperature as a function of time using an optical sensor embedded downstream in the material. Optical beams are used to deposit energy and to measure the sensor temperature and replace the resistive heat source and the thermocouples of previous methods. This overcomes the problems introduced with pressure-induced resistance changes and the spatial limitations inherent in previous high-pressure experimentation. Consistent with the heat conduction equation, the material's specific heat, thermal conductivity, and thermal diffusivity (κ) determine the sensor's temperature rise and its temporal profile. The all-optical technique described focuses on room-temperature thermal properties but can easily be applied to a wide temperature range (77-600 K). Measurements of thermal transport properties at pressure up to 2.0 GPa are reported, although extension to much higher pressures are feasible. The thermal properties of NaCl, a commonly used material for high-pressure experiments are measured and shown to be consistent with those obtained using the traditional methods.

Composite Silica Aerogels Opacified with Titania

NASA Technical Reports Server (NTRS)

Paik, Jon-Ah; Sakamoto, Jeffrey; Jones, Steven; Fleurial, Jean-Pierre; DiStefano, Salvador; Nesmith, Bill

2009-01-01

A further improvement has been made to reduce the high-temperature thermal conductivities of the aerogel-matrix composite materials described in Improved Silica Aerogel Composite Materials (NPO-44287), NASA Tech Briefs, Vol. 32, No. 9 (September 2008), page 50. Because the contribution of infrared radiation to heat transfer increases sharply with temperature, the effective high-temperature thermal conductivity of a thermal-insulation material can be reduced by opacifying the material to reduce the radiative contribution. Therefore, the essence of the present improvement is to add an opacifying constituent material (specifically, TiO2 powder) to the aerogel-matrix composites.

Tensile Strength and Microstructure of Al2O3-ZrO2 Hypo-Eutectic Fibers Studied

NASA Technical Reports Server (NTRS)

Farmer, Serene C.; Sayir, Ali

2001-01-01

Oxide eutectics offer high-temperature strength retention and creep resistance in oxidizing environments. Al2O3-ZrO2 eutectic strengths have been studied since the 1970's. Directionally solidified oxide eutectics exhibit improved resistance to slow crack growth and excellent strength retention at high temperatures up to 1400 C. Materials studied typically contain Y2O3 to metastably retain the high-temperature cubic and tetragonal polymorphs at room temperature. Al2O3-ZrO2 is of fundamental interest for creep studies because it combines a creep-resistant material, Al2O3, with a very low creep resistance material, ZrO2. Results on mechanical properties and microstructures of these materials will be used to define compositions for creep testing in future work. Substantial variations from the eutectic alumina to zirconia ratio can be tolerated without a loss in room-temperature strength. The effect of increasing Y2O3 addition on the room-temperature tensile strength of an Al2O3-ZrO2 material containing excess Al2O3 was examined at the NASA Glenn Research Center, where the materials were grown using Glenn's world-class laser growth facilities.

Deformation and annealing study of NiCrAlY

NASA Technical Reports Server (NTRS)

Ebert, L. J.; Trela, D. M.

1978-01-01

The elevated temperature properties (tensile and creep) of NiCrALY, a nickel base alloy containing nominally 16% chromium, 4% aluminum, and 2 to 3% yttria (Y2O3) were evaluated and the optimal combination of thermomechanical treatments for maximum creep resistance was determined. Stored strain energy in as-extruded bars (14:1 extrusion ratio) permitted the development of a large grain size in the material when it was annealed at the maximum safe temperature 2450 F (1343 C). With a one-hour anneal at this temperature, the relatively fine grain size of the as-extruded material was changed to one in which the average grain diameter approached 1 mm, and the aspect ratio was about 10. The material was capable of being cold worked (by rolling) in amounts greater than 30% reduction in area. When the cold worked material was given a relaxation treatment, consisting of heating one hour at 1600 F(871 C), and then a high temperature anneal at 2450 F (1343 C) for one hour, both the high temperature strength and the high temperature creep resistance of the material was further enhanced.

Pseudo-icosahedral Cr 55 Al 232 - δ as a high-temperature protective material

DOE PAGES

Rosa, R.; Bhattacharya, S.; Pabla, J.; ...

2018-03-19

In this paper, we report here a course of basic research into the potential suitability of a pseudo-icosahedral Cr aluminide as a material for high temperature protective coatings. Cr 55Al 232-δ [δ = 2.70(6)] exhibits high hardness at room temperature as well as low thermal conductivity and excellent oxidation resistance at 973 K, with an oxidation rate comparable to those of softer, denser benchmark materials. Lastly, the origin of these promising properties can be traced to competing long-range and short-range symmetries within the pseudo-icosahedral crystal structure, suggesting new criteria for future materials research.

Pseudo-icosahedral Cr 55 Al 232 - δ as a high-temperature protective material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosa, R.; Bhattacharya, S.; Pabla, J.

In this paper, we report here a course of basic research into the potential suitability of a pseudo-icosahedral Cr aluminide as a material for high temperature protective coatings. Cr 55Al 232-δ [δ = 2.70(6)] exhibits high hardness at room temperature as well as low thermal conductivity and excellent oxidation resistance at 973 K, with an oxidation rate comparable to those of softer, denser benchmark materials. Lastly, the origin of these promising properties can be traced to competing long-range and short-range symmetries within the pseudo-icosahedral crystal structure, suggesting new criteria for future materials research.

Review: Potential Strength of Fly Ash-Based Geopolymer Paste with Substitution of Local Waste Materials with High-Temperature Effect

NASA Astrophysics Data System (ADS)

Subekti, S.; Bayuaji, R.; Darmawan, M. S.; Husin, N. A.; Wibowo, B.; Anugraha, B.; Irawan, S.; Dibiantara, D.

2017-11-01

This research provided an overview of the potential fly ash based geopolymer paste for application in building construction. Geopolymer paste with various variations of fly ash substitution with local waste material and high-temperature influence exploited with the fresh and hardened condition. The local waste material which utilized for this study were sandblasting waste, carbide waste, shell powder, bagasse ash, rice husk and bottom ash. The findings of this study indicated that fly-based geopolymer paste with local waste material substitution which had high-temperature influence ash showed a similar nature of OPC binders potentially used in civil engineering applications.

Abrasive wear of ceramic wear protection at ambient and high temperatures

NASA Astrophysics Data System (ADS)

Varga, M.; Adam, K.; Tumma, M.; Alessio, K. O.

2017-05-01

Ceramic wear protection is often applied in abrasive conditions due to their excellent wear resistance. This is especially necessary in heavy industries conveying large amounts of raw materials, e.g. in steel industry. Some plants also require material transport at high temperatures and velocities, making the need of temperature stable and abrasion resistant wear protection necessary. Various types and wear behaviour of ceramic protection are known. Hence, the goal of this study is to identify the best suitable ceramic materials for abrasive conditions in harsh environments at temperatures up to 950°C and severe thermal gradients. Chamottes, known for their excellent thermal shock resistance are compared to high abrasion resistant ceramic wear tiles and a cost efficient cement-bounded hard compound. Testing was done under high-stress three-body abrasion regime with a modified ASTM G65 apparatus enabling for investigations up to ~950°C. Thereto heated abrasive is introduced into the wear track and also preheated ceramic samples were used and compared to ambient temperature experiments. Results indicate a significant temperature influence on chamottes and the hard compound. While the chamottes benefit from temperature increase, the cement-bounded hard compound showed its limitation at abrasive temperatures of 950°C. The high abrasion resistant wear tiles represented the materials with the best wear resistance and less temperature influence in the investigated range.

Development and testing of a superconducting link for an IR detector

NASA Technical Reports Server (NTRS)

Caton, R.; Selim, R.

1991-01-01

The development and testing of a ceramic superconducting link for an infrared detector is summarized. Areas of study included the materials used, the electrical contacts, radiation and temperature cycling effects, aging, thermal conductivity, and computer models of an ideal link. Materials' samples were processed in a tube furnace at temperatures of 840 C to 865 C for periods up to 17 days and transition temperatures and critical current densities were recorded. The project achieved better quality high superconducting transition temperature material through improved processing and also achieved high quality electrical contacts. Studies on effects of electron irradiation, temperature cycling, and aging on superconducting properties indicate that the materials will be suitable for space applications. Various presentations and publications on the study's results are reported.

Comparison of high temperature, high frequency core loss and dynamic B-H loops of a 2V-49Fe-49Co and a grain oriented 3Si-Fe alloy

NASA Technical Reports Server (NTRS)

Wieserman, W. R.; Schwarze, G. E.; Niedra, J. M.

1992-01-01

The design of power magnetic components such as transformers, inductors, motors, and generators, requires specific knowledge about the magnetic and electrical characteristics of the magnetic materials used in these components. Limited experimental data exists that characterizes the performance of soft magnetic materials for the combined conditions of high temperature and high frequency over a wide flux density range. An experimental investigation of a 2V-49-Fe-49Co (Supermendur) and a grain oriented 3 Si-Fe (Magnesil) alloy was conducted over the temperature range of 23 to 300 C and frequency range of 0.1 to 10 kHz. The effects of temperature, frequency, and maximum flux density on the core loss and dynamic B-H loops for sinusoidal voltage excitation conditions are examined for each of these materials. A comparison of the core loss of these two materials is also made over the temperature and frequency range investigated.

Irradiation effect of the insulating materials for fusion superconducting magnets at cryogenic temperature

NASA Astrophysics Data System (ADS)

Kobayashi, Koji; Akiyama, Yoko; Nishijima, Shigehiro

2017-09-01

In ITER, superconducting magnets should be used in such severe environment as high fluence of fast neutron, cryogenic temperature and large electromagnetic forces. Insulating material is one of the most sensitive component to radiation. So radiation resistance on mechanical properties at cryogenic temperature are required for insulating material. The purpose of this study is to evaluate irradiation effect of insulating material at cryogenic temperature by gamma-ray irradiation. Firstly, glass fiber reinforced plastic (GFRP) and hybrid composite were prepared. After irradiation at room temperature (RT) or liquid nitrogen temperature (LNT, 77 K), interlaminar shear strength (ILSS) and glass-transition temperature (Tg) measurement were conducted. It was shown that insulating materials irradiated at room temperature were much degraded than those at cryogenic temperature.

Thermal Testing and Analysis of an Efficient High-Temperature Multi-Screen Internal Insulation

NASA Technical Reports Server (NTRS)

Weiland, Stefan; Handrick, Karin; Daryabeigi, Kamran

2007-01-01

Conventional multi-layer insulations exhibit excellent insulation performance but they are limited to the temperature range to which their components reflective foils and spacer materials are compatible. For high temperature applications, the internal multi-screen insulation IMI has been developed that utilizes unique ceramic material technology to produce reflective screens with high temperature stability. For analytical insulation sizing a parametric material model is developed that includes the main contributors for heat flow which are radiation and conduction. The adaptation of model-parameters based on effective steady-state thermal conductivity measurements performed at NASA Langley Research Center (LaRC) allows for extrapolation to arbitrary stack configurations and temperature ranges beyond the ones that were covered in the conductivity measurements. Experimental validation of the parametric material model was performed during the thermal qualification test of the X-38 Chin-panel, where test results and predictions showed a good agreement.

Corrosion of Ceramic Materials

NASA Technical Reports Server (NTRS)

Opila, Elizabeth J.; Jacobson, Nathan S.

1999-01-01

Non-oxide ceramics are promising materials for a range of high temperature applications. Selected current and future applications are listed. In all such applications, the ceramics are exposed to high temperature gases. Therefore it is critical to understand the response of these materials to their environment. The variables to be considered here include both the type of ceramic and the environment to which it is exposed. Non-oxide ceramics include borides, nitrides, and carbides. Most high temperature corrosion environments contain oxygen and hence the emphasis of this chapter will be on oxidation processes.

NASA's high-temperature engine materials program for civil aeronautics

NASA Technical Reports Server (NTRS)

Gray, Hugh R.; Ginty, Carol A.

1992-01-01

The Advanced High-Temperature Engine Materials Technology Program is described in terms of its research initiatives and its goal of developing propulsion systems for civil aeronautics with low levels of noise, pollution, and fuel consumption. The program emphasizes the analysis and implementation of structural materials such as polymer-matrix composites in fans, casings, and engine-control systems. Also investigated in the program are intermetallic- and metal-matrix composites for uses in compressors and turbine disks as well as ceramic-matrix composites for extremely high-temperature applications such as turbine vanes.

High Temperature Thermographic Phosphor Coatings Development

NASA Technical Reports Server (NTRS)

Goedeke, Shawn; Allison, S. W.; Beshears, D. L.; Bencic, T.; Cates, M. R.; Hollerman, W. A.; Guidry, R.

2003-01-01

For many years, phosphor thermometry has been used for non-contact temperature measurements. A large number of applications have been associated with high temperatures, especially for aerospace systems where blackbody radiation backgrounds are large and in challenging environments, such as vibration, rotation, flame, or noise. These environments restrict the use of more common thermocouples or infrared thermometric techniques. In particular, temperature measurements inside jet turbines, rocket engines, or similar devices are especially amenable to phosphor techniques. Often the fluorescent materials are used as powders, either suspended in binders and applied like paint or applied as high-temperature sprays. Thin coatings that are less than 50 m thick are used on the surfaces of interest. These coatings will quickly assume the same temperature as the surface to which they are applied. The temperature dependence of fluorescent materials is a function of the base matrix atoms and a small quantity of added activator or dopant ions. Often for high temperature applications, the selected materials are refractory and include rare earth ions. Phosphors like Y3Al5O12 (YAG) doped with Eu, Dy, or Tm, Y2O3 doped with Eu, or similar rare earth compounds, will survive high temperatures and can be configured to emit light that changes rapidly in lifetime and intensity. For example, researchers at Oak Ridge National Laboratory recently observed fluorescence from YAG:Dy and YAG:Tm at temperatures above 1400 C. One of the biggest challenges is to locate a binder material that can withstand tremendous variations in temperature in an adverse aerospace environment. This poster will provide an overview into our attempt to utilize phosphors for thermometry purposes. Emphasis will be placed on the use of selected binder materials that can withstand high temperatures. This research was completed for the National Aeronautics and Space Administration's Glenn Research Center in Cleveland, Ohio.

Applying MHD Results to a Scramjet Vehicle

DTIC Science & Technology

2007-02-12

flow, arc formation and extinction, high temperature materials, and non-intrusive gas diagnostics. In this report, results from the DOE Program, and...3) Use of demonstrated non-intrusive diagnostics for plasma and boundary layer measurements, and (4) Testing of high - temperature materials for an MHD...cycle systems with researchers in Eindhoven, The Netherlands, and open-cycle systems with personnel at the High Temperature Institute, Moscow, Russia

Castable hot corrosion resistant alloy

NASA Technical Reports Server (NTRS)

Barrett, Charles A. (Inventor); Holt, William H. (Inventor)

1988-01-01

Some 10 wt percent nickel is added to an Fe-base alloy which has a ferrite microstructure to improve the high temperature castability and crack resistance while about 0.2 wt percent zirconium is added for improved high temperatur cyclic oxidation and corrosion resistance. The basic material is a high temperature FeCrAl heater alloy, and the addition provides a material suitable for burner rig nozzles.

Dielectric Performance of a High Purity HTCC Alumina at High Temperatures - a Comparison Study with Other Polycrystalline Alumina

NASA Technical Reports Server (NTRS)

Chen, Liangyu

2014-01-01

A very high purity (99.99+%) high temperature co-fired ceramic (HTCC) alumina has recently become commercially available. The raw material of this HTCC alumina is very different from conventional HTCC alumina, and more importantly there is no glass additive in this alumina material for co-firing processing. Previously, selected HTCC and LTCC (low temperature co-fired ceramic) alumina materials were evaluated at high temperatures as dielectric and compared to a regularly sintered 96% polycrystalline alumina (96% Al2O3), where 96% alumina was used as the benchmark. A prototype packaging system based on regular 96% alumina with Au thickfilm metallization successfully facilitated long term testing of high temperature silicon carbide (SiC) electronic devices for over 10,000 hours at 500 C. In order to evaluate this new high purity HTCC alumina for possible high temperature packaging applications, the dielectric properties of this HTCC alumina substrate were measured and compared with those of 96% alumina and a previously tested LTCC alumina from room temperature to 550 C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. A parallel-plate capacitive device with dielectric of the HTCC alumina and precious metal electrodes were used for measurements of the dielectric constant and dielectric loss of the co-fired alumina material in the temperature and frequency ranges. The capacitance and AC parallel conductance of the capacitive device were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of the HTCC alumina substrate are presented and compared to those of 96% alumina and a selected LTCC alumina. Other technical advantages of this new co-fired material for possible high packaging applications are also discussed.

Glasses and Liquids Low on the Energy Landscape Prepared by Physical Vapor Deposition

NASA Astrophysics Data System (ADS)

Dalal, Shakeel; Fakhraai, Zahra; Ediger, Mark

2014-03-01

The lower portions of the potential energy landscape for glass-forming materials such as polymers and small molecules were historically inaccessible by experiments. Physical vapor deposition is uniquely able to prepare materials in this portion of the energy landscape, with the properties of the deposited material primarily modulated by the substrate temperature. Here we report on high-throughput experiments which utilize a temperature gradient stage to enable rapid screening of vapor-deposited organic glasses. Using ellipsometry, we characterize a 100 K range of substrate temperatures in a single experiment, allowing us to rapidly determine the density, kinetic stability, fictive temperature and molecular orientation of these glasses. Their properties fall into three temperature regimes. At substrate temperatures as low as 0.97Tg, we prepare materials which are equivalent to the supercooled liquid produced by cooling the melt. Below 0.9Tg (1.16TK) the properties of materials are kinetically controlled and highly tunable. At intermediate substrate temperatures we are able to produce materials whose bulk properties match those expected for the equilibrium supercooled liquid, down to 1.16TK, but are structurally anisotropic.

The Role of Molecular Weight and Temperature on the Elastic and Viscoelastic Properties of a Glassy Thermoplastic Polyimide

NASA Technical Reports Server (NTRS)

Nicholson, Lee M.; Whitley, Karen S.; Gates, Thomas S.

2001-01-01

Mechanical testing of the elastic and viscoelastic response of an advanced thermoplastic polyimide (LaRC-SI) with known variations in molecular weight was performed over a range of temperatures below the glass transition temperature. The notched tensile strength was shown to be a strong function of both molecular weight and temperature, whereas stiffness was only a strong function of temperature. A critical molecular weight was observed to occur at a weight average molecular weight of M, approx. 22,000 g/mol below which, the notched tensile strength decreases rapidly. This critical molecular weight transition is temperature-independent. Low, molecular weight materials tended to fail in a brittle manner, whereas high molecular weight materials exhibited ductile failure. Furthermore, low molecular weight materials have increased creep compliance and creep compliance rate, and are more sensitive to temperature than the high molecular weight materials. At long timescales (less than 1100 hours) physical aging serves to significantly decrease the creep compliance and creep rate of all the materials tested. Low molecular weight materials are less influenced by the effects of physical aging.

Microstructure and properties of cryomilled nickel aluminide extruded with chromium or molybdenum

NASA Technical Reports Server (NTRS)

Aikin, Beverly J. M.; Dickerson, Robert M.; Dickerson, Patricia O.

1995-01-01

Previous results from high energy, attrition milled NiAl in liquid nitrogen (cryomilled) indicate that this process can produce high temperature, creep resistant AlN particulate reinforced materials. However, the low temperature toughness of such materials is below that preferred for structural applications in aerospace engines. In order to improve the toughness of these materials, prealloyed nickel aluminide (Ni-53 atomic percent Al) powder was cryomilled and mixed with chromium or molybdenum powders. The resulting materials were hot extruded and tested for room temperature toughness and 1300 K compressive strength.

Investigation of high temperature antennas for space shuttle

NASA Technical Reports Server (NTRS)

Kuhlman, E. A.

1973-01-01

The design and development of high temperature antennas for the space shuttle orbiter are discussed. The antenna designs were based on three antenna types, an annular slot (L-Band), a linear slot (C-Band), and a horn (C-Band). The design approach was based on combining an RF window, which provides thermal protection, with an off-the-shelf antenna. Available antenna window materials were reviewed and compared, and the materials most compatible with the design requirements were selected. Two antenna window design approaches were considered: one employed a high temperature dielectric material and a low density insulation material, and the other an insulation material usable for the orbiter thermal protection system. Preliminary designs were formulated and integrated into the orbiter structure. Simple electrical models, with a series of window configurations, were constructed and tested. The results of tests and analyses for the final antenna system designs are given and show that high temperature antenna systems consisting of off-the-shelf antennas thermally protected by RF windows can be designed for the Space Shuttle Orbiter.

Refractory materials for high-temperature thermoelectric energy conversion

NASA Technical Reports Server (NTRS)

Wood, C.; Emin, D.

1983-01-01

Theoretical work of two decades ago adequately explained the transport behavior and effectively guided the development of thermoelectric materials of high conversion efficiencies of conventional semiconductors (e.g., SiGe alloys). The more significant contributions involved the estimation of optimum doping concentrations, the reduction of thermal conductivity by solid solution doping and the development of a variety of materials with ZT approx. 1 in the temperature range 300 K to 1200 K. ZT approx. 1 is not a theoretical limitation although, experimentally, values in excess of one were not achieved. Work has continued with emphasis on higher temperature energy conversion. A number of promising materials have been discovered in which it appears that ZT 1 is realizable. These materials are divided into two classes: (1) the rare-earth chalcogenides which behave as itinerant highly-degenerate n-type semiconductors at room-temperature, and (2) the boron-rich borides, which exhibit p-type small-polaronic hopping conductivity.

Development of an analytical environmental TEM system and its application.

PubMed

Kishita, Keisuke; Sakai, Hisashi; Tanaka, Hiromochi; Saka, Hiroyasu; Kuroda, Kotaro; Sakamoto, Masayuki; Watabe, Akira; Kamino, Takeo

2009-12-01

Many automotive materials, such as catalysts and fuel cell materials, undergo significant changes in structure or properties when subjected to temperature change or the addition of a gas. For this reason, in the development of these materials, it is important to study the behavior of the material under controlled temperatures and gaseous atmospheres. Recently, a new environmental transmission electron microscope (TEM) has been developed for observation with a high resolution at high temperatures and under gaseous atmospheres, thus making it possible to analyze reaction processes in details. Also, the new TEM provides a high degree of reproducibility of observation conditions, thus making it possible to compare and validate observation of various specimens under a given set of conditions. Furthermore, easiness of gas condition and temperature control can provide a powerful tool for the studying of the mechanism of material change, such as oxidation and reduction reactions.

Potential High-Temperature Shape-Memory Alloys Identified in the Ti(Ni,Pt) System

NASA Technical Reports Server (NTRS)

Noebe, Ronald D.; Biles, Tiffany A.; Garg, Anita; Nathal, Michael V.

2004-01-01

"Shape memory" is a unique property of certain alloys that, when deformed (within certain strain limits) at low temperatures, will remember and recover to their original predeformed shape upon heating. It occurs when an alloy is deformed in the low-temperature martensitic phase and is then heated above its transformation temperature back to an austenitic state. As the material passes through this solid-state phase transformation on heating, it also recovers its original shape. This behavior is widely exploited, near room temperature, in commercially available NiTi alloys for connectors, couplings, valves, actuators, stents, and other medical and dental devices. In addition, there are limitless applications in the aerospace, automotive, chemical processing, and many other industries for materials that exhibit this type of shape-memory behavior at higher temperatures. But for high temperatures, there are currently no commercial shape-memory alloys. Although there are significant challenges to the development of high-temperature shape-memory alloys, at the NASA Glenn Research Center we have identified a series of alloy compositions in the Ti-Ni-Pt system that show great promise as potential high-temperature shape-memory materials.

Containerless high temperature property measurements

NASA Technical Reports Server (NTRS)

Nordine, Paul C.; Weber, J. K. Richard; Krishnan, Shankar; Anderson, Collin D.

1991-01-01

Containerless processing in the low gravity environment of space provides the opportunity to increase the temperature at which well controlled processing of and property measurements on materials is possible. This project was directed towards advancing containerless processing and property measurement techniques for application to materials research at high temperatures in space. Containerless high temperature material property studies include measurements of the vapor pressure, melting temperature, optical properties, and spectral emissivities of solid boron. The reaction of boron with nitrogen was also studied by laser polarimetric measurement of boron nitride film growth. The optical properties and spectral emissivities were measured for solid and liquid silicon, niobium, and zirconium; liquid aluminum and titanium; and liquid Ti-Al alloys of 5 to 60 atomic pct. titanium. Alternative means for noncontact temperature measurement in the absence of material emissivity data were evaluated. Also, the application of laser induced fluorescence for component activity measurements in electromagnetic levitated liquids was studied, along with the feasibility of a hybrid aerodynamic electromagnetic levitation technique.

Acoustic levitation for high temperature containerless processing in space

NASA Technical Reports Server (NTRS)

Rey, C. A.; Sisler, R.; Merkley, D. R.; Danley, T. J.

1990-01-01

New facilities for high-temperature containerless processing in space are described, including the acoustic levitation furnace (ALF), the high-temperature acoustic levitator (HAL), and the high-pressure acoustic levitator (HPAL). In the current ALF development, the maximum temperature capabilities of the levitation furnaces are 1750 C, and in the HAL development with a cold wall furnace they will exceed 2000-2500 C. The HPAL demonstrated feasibility of precursor space flight experiments on the ground in a 1 g pressurized-gas environment. Testing of lower density materials up to 1300 C has also been accomplished. It is suggested that advances in acoustic levitation techniques will result in the production of new materials such as ceramics, alloys, and optical and electronic materials.

Performance testing of elastomeric seal materials under low and high temperature conditions: Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

BRONOWSKI,DAVID R.

The US Department of Energy Offices of Defense Programs and Civilian Radioactive Waste Management jointly sponsored a program to evaluate elastomeric O-ring seal materials for radioactive material shipping containers. The report presents the results of low- and high-temperature tests conducted on 27 common elastomeric compounds.

Polyimide Resins Resist Extreme Temperatures

NASA Technical Reports Server (NTRS)

2009-01-01

Spacecraft and aerospace engines share a common threat: high temperature. The temperatures experienced during atmospheric reentry can reach over 2,000 F, and the temperatures in rocket engines can reach well over 5,000 F. To combat the high temperatures in aerospace applications, Dr. Ruth Pater of Langley Research Center developed RP-46, a polyimide resin capable of withstanding the most brutal temperatures. The composite material can push the service temperature to the limits of organic materials. Designed as an environmentally friendly alternative to other high-temperature resins, the RP-46 polyimide resin system was awarded a 1992 "R&D 100" award, named a "2001 NASA Technology of the Year," and later, due to its success as a spinoff technology, "2004 NASA Commercial Invention of the Year." The technology s commercial success also led to its winning the Langley s "Paul F. Holloway Technology Transfer Award" as well as "Richard T. Whitcom Aerospace Technology Transfer Award" both for 2004. RP-46 is relatively inexpensive and it can be readily processed for use as an adhesive, composite, resin molding, coating, foam, or film. Its composite materials can be used in temperatures ranging from minus 150 F to 2,300 F. No other organic materials are known to be capable of such wide range and extreme high-temperature applications. In addition to answering the call for environmentally conscious high-temperature materials, RP-46 provides a slew of additional advantages: It is extremely lightweight (less than half the weight of aluminum), chemical and moisture resistant, strong, and flexible. Pater also developed a similar technology, RP-50, using many of the same methods she used with RP-46, and very similar in composition to RP-46 in terms of its thermal capacity and chemical construction, but it has different applications, as this material is a coating as opposed to a buildable composite. A NASA license for use of this material outside of the Space Agency as well as additional government-funded testing proved that RP-46 is even more exceptional than originally thought.

Aerospace Ceramic Materials: Thermal, Environmental Barrier Coatings and SiC/SiC Ceramic Matrix Composites for Turbine Engine Applications

NASA Technical Reports Server (NTRS)

Zhu, Dongming

2018-01-01

Ceramic materials play increasingly important roles in aerospace applications because ceramics have unique properties, including high temperature capability, high stiffness and strengths, excellent oxidation and corrosion resistance. Ceramic materials also generally have lower densities as compared to metallic materials, making them excellent candidates for light-weight hot-section components of aircraft turbine engines, rocket exhaust nozzles, and thermal protection systems for space vehicles when they are being used for high-temperature and ultra-high temperature ceramics applications. Ceramic matrix composites (CMCs), including non-oxide and oxide CMCs, are also recently being incorporated in gas turbine engines for high pressure and high temperature section components and exhaust nozzles. However, the complexity and variability of aerospace ceramic processing methods, compositions and microstructures, the relatively low fracture toughness of the ceramic materials, still remain the challenging factors for ceramic component design, validation, life prediction, and thus broader applications. This ceramic material section paper presents an overview of aerospace ceramic materials and their characteristics. A particular emphasis has been placed on high technology level (TRL) enabling ceramic systems, that is, turbine engine thermal and environmental barrier coating systems and non-oxide type SiC/SiC CMCs. The current status and future trend of thermal and environmental barrier coatings and SiC/SiC CMC development and applications are described.

Ultrahigh-Temperature Ceramics

NASA Technical Reports Server (NTRS)

Johnson, Sylvia M.; Ellerby, Donald T.; Beckman, Sarah E.; Irby, Edward; Gasch, Matthew J.; Gusman, Michael I.

2007-01-01

Ultrahigh temperature ceramics (UHTCs) are a class of materials that include the diborides of metals such as hafnium and zirconium. The materials are of interest to NASA for their potential utility as sharp leading edges for hypersonic vehicles. Such an application requires that the materials be capable of operating at temperatures, often in excess of 2,000 C. UHTCs are highly refractory and have high thermal conductivity, an advantage for this application. UHTCs are potentially applicable for other high-temperature processing applications, such as crucibles for molten-metal processing and high-temperature electrodes. UHTCs were first studied in the 1960 s by the U.S. Air Force. NASA s Ames Research Center concentrated on developing materials in the HfB2/SiC family for a leading-edge application. The work focused on developing a process to make uniform monolithic (2-phase) materials, and on the testing and design of these materials. Figure 1 shows arc-jet models made from UHTC materials fabricated at Ames. Figure 2 shows a cone being tested in the arc-jet. Other variations of these materials being investigated elsewhere include zirconium based materials and fiber-reinforced composites. Current UHTC work at Ames covers four broad topics: monoliths, coatings, composites, and processing. The goals include improving the fracture toughness, thermal conductivity and oxidation resistance of monolithic UHTCs and developing oxidation-resistant UHTC coatings for thermal-protection-system substrates through novel coating methods. As part of this effort, researchers are exploring compositions and processing changes that have yielded improvements in properties. Computational materials science and nanotechnology are being explored as approaches to reduce materials development time and improve and tailor properties.

High Temperature Polymeric Materials for Space Transportation Propulsion Applications

NASA Technical Reports Server (NTRS)

Meador, Michael A.; Campbell, Sandi G.; Chuang, Kathy C.; Scheimann, Daniel A.; Mintz, Eric; Hylton, Donald; Veazie, David; Criss, James; Kollmansberg, Ron; Tsotsis, Tom

2003-01-01

High temperature polymer matrix composites are attractive materials for space transporation propulsion systems because of their low density and high specific strength. However, the relatively poor stability and processability of these materials can render them unsuitable for many of these applications. New polymeric materials have been developed under the Propulsion Research and Technology Program through the use of novel resin chemistry and nanotechnology. These new materials can significantly enhance the durability and weight and improve the processability and affordability of propulsion components for advanced space transportation systems.

Oxidation characteristics of MgF2 in air at high temperature

NASA Astrophysics Data System (ADS)

Chen, H. K.; Jie, Y. Y.; Chang, L.

2017-02-01

High temperature oxidation properties of MgF2 in air were studied. The changes of phase composition, macro surface morphology, weight and elemental composition of MgF2 samples with temperature were investigated by using XRD, EDS and gravimetric analyses. The results show that the oxidation reaction of MgF2 converted to MgO occurred at high temperature, and the reaction was accelerated by the increase of temperature and the presence of impurities. This result clarifies the understanding of the high temperature oxidation behavior of MgF2 in air, and provides a theoretical basis for the reasonable application of MgF2 in optical coating materials, electronic ceramic materials and magnesium melt protection.

Powder Processing of High Temperature Cermets and Carbides at Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Salvail, Pat; Panda, Binayak; Hickman, Robert R.

2007-01-01

The Materials and Processing Laboratory at NASA Marshall Space Flight Center is developing Powder Metallurgy (PM) processing techniques for high temperature cermet and carbide material consolidation. These new group of materials would be utilized in the nuclear core for Nuclear Thermal Rockets (NTR). Cermet materials offer several advantages for NTR such as retention of fission products and fuels, better thermal shock resistance, hydrogen compatibility, high thermal conductivity, and high strength. Carbide materials offer the highest operating temperatures but are sensitive to thermal stresses and are difficult to process. To support the effort, a new facility has been setup to process refractory metal, ceramic, carbides and depleted uranium-based powders. The facility inciudes inert atmosphere glove boxes for the handling of reactive powders, a high temperature furnace, and powder processing equipment used for blending, milling, and sieving. The effort is focused on basic research to identify the most promising compositions and processing techniques. Several PM processing methods including Cold and Hot Isostatic Pressing are being evaluated to fabricate samples for characterization and hot hydrogen testing.

Mechanical and Microstructure Study of Nickel-Based ODS Alloys Processed by Mechano-Chemical Bonding and Ball Milling

NASA Astrophysics Data System (ADS)

Amare, Belachew N.

Due to the need to increase the efficiency of modern power plants, land-based gas turbines are designed to operate at high temperature creating harsh environments for structural materials. The elevated turbine inlet temperature directly affects the materials at the hottest sections, which includes combustion chamber, blades, and vanes. Therefore, the hottest sections should satisfy a number of material requirements such as high creep strength, ductility at low temperature, high temperature oxidation and corrosion resistance. Such requirements are nowadays satisfied by implementing superalloys coated by high temperature thermal barrier coating (TBC) systems to protect from high operating temperature required to obtain an increased efficiency. Oxide dispersive strengthened (ODS) alloys are being considered due to their high temperature creep strength, good oxidation and corrosion resistance for high temperature applications in advanced power plants. These alloys operating at high temperature are subjected to different loading systems such as thermal, mechanical, and thermo-mechanical combined loads at operation. Thus, it is critical to study the high temperature mechanical and microstructure properties of such alloys for their structural integrity. The primary objective of this research work is to investigate the mechanical and microstructure properties of nickel-based ODS alloys produced by combined mechano-chemical bonding (MCB) and ball milling subjected to high temperature oxidation, which are expected to be applied for high temperature turbine coating with micro-channel cooling system. Stiffness response and microstructure evaluation of such alloy systems was studied along with their oxidation mechanism and structural integrity through thermal cyclic exposure. Another objective is to analyze the heat transfer of ODS alloy coatings with micro-channel cooling system using finite element analysis (FEA) to determine their feasibility as a stand-alone structural coating. During this project it was found that stiffness response to increase and remain stable to a certain level and reduce at latter stages of thermal cyclic exposure. The predominant growth and adherent Ni-rich outer oxide scale was found on top of the alumina scale throughout the oxidation cycles. The FEA analysis revealed that ODS alloys could be potential high temperature turbine coating materials if micro-channel cooling system is implemented.

Thermal design of composite material high temperature attachments

NASA Technical Reports Server (NTRS)

1972-01-01

An evaluation has been made of the thermal aspects of utilizing advanced filamentary composite materials as primary structures on the shuttle vehicle. The technical objectives of this study are to: (1) establish and design concepts for maintaining material temperatures within allowable limits at TPS attachments and or penetrations applicable to the space shuttle; and (2) verify the thermal design analysis by testing selected concepts. Specific composite materials being evaluated are boron epoxy, graphite/epoxy, boron polyimide, and boron aluminum; graphite/polyimide has been added to this list for property data identification and preliminary evaluation of thermal design problems. The TPS standoff to composite structure attachment over-temperature problem is directly related to TPS maximum surface temperature. To provide a thermally comprehensive evaluation of attachment temperature characteristics, maximum surface temperatures of 900 F, 1200 F, 1800 F, 2500 F and 3000 F are considered in this study. This range of surface temperatures and the high and low maximum temperature capability of the selected composite materials will result in a wide range of thermal requirements for composite/TPS standoff attachments.

High temperature material interactions of thermoelectric systems using silicon germanium.

NASA Technical Reports Server (NTRS)

Stapfer, G.; Truscello, V. C.

1973-01-01

The efficient use of silicon germanium thermoelectric material for radioisotope thermoelectric generators (RTG) is achieved by operation at relatively high temperatures. The insulation technique which is most appropriate for this application uses multiple layers of molybdenum foil and astroquartz. Even so, the long term operation of these materials at elevated temperatures can cause material interaction to occur within the system. To investigate these material interactions, the Jet Propulsion Laboratory is currently testing a number of thermoelectric modules which use four silicon germanium thermoelectric couples in conjunction with the multifoil thermal insulation. The paper discusses the results of the ongoing four-couple module test program and correlates test results with those of a basic material test program.

Ab initio Computations of the Electronic, Mechanical, and Thermal Properties of Ultra High Temperature Ceramics (UHTC) ZrB2 and HfB2

NASA Technical Reports Server (NTRS)

Lawson, John W.; Bauschlicher, Charles W.; Daw, Murray

2011-01-01

Refractory materials such as metallic borides, often considered as ultra high temperature ceramics (UHTC), are characterized by high melting point, high hardness, and good chemical inertness. These materials have many applications which require high temperature materials that can operate with no or limited oxidation. Ab initio, first principles methods are the most accurate modeling approaches available and represent a parameter free description of the material based on the quantum mechanical equations. Using these methods, many of the intrinsic properties of these material can be obtained. We performed ab initio calculations based on density functional theory for the UHTC materials ZrB2 and HfB2. Computational results are presented for structural information (lattice constants, bond lengths, etc), electronic structure (bonding motifs, densities of states, band structure, etc), thermal quantities (phonon spectra, phonon densities of states, specific heat), as well as information about point defects such as vacancy and antisite formation energies.

Characterization Report on Fuels for NEAMS Model Validation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gofryk, Krzysztof

Nearly 20% of the world’s electricity today is generated by nuclear energy from uranium dioxide (UO 2) fuel. The thermal conductivity of UO 2 governs the conversion of heat produced from fission events into electricity and it is an important parameter in reactor design and safety. While nuclear fuel operates at high to very high temperatures, thermal conductivity and other materials properties lack sensitivity to temperature variations and to material variations at reactor temperatures. As a result, both the uncertainties in laboratory measurements at high temperatures and the small differences in properties of different materials inevitably lead to large uncertaintiesmore » in models and little predictive power. Conversely, properties measured at low to moderate temperatures have more sensitivity, less uncertainty, and have larger differences in properties for different materials. These variations need to be characterized as they will afford the highest predictive capability in modeling and offer best assurances for validation and verification at all temperatures. This is well emphasized in the temperature variation of the thermal conductivity of UO 2.« less

High temperature volatility and oxidation measurements of titanium and silicon containing ceramic materials

NASA Astrophysics Data System (ADS)

Nguyen, Quynhgiao N.

Titanium (Ti) containing materials are of high interest to the aerospace industry due to its high temperature capability, strength, and light weight. As with most metals an exterior oxide layer naturally exists in environments that contain oxygen (i.e. air). At high temperatures, water vapor plays a key role in the volatility of materials including oxide surfaces. This study first evaluates several hot-pressed Ti-containing compositions at high temperatures as a function of oxidation resistance. This study will also evaluate cold pressed titanium dioxide (TiO2) powder pellets at a temperature range of 1400°C--1200°C in water containing environments to determine the volatile hydoxyl species using the transpiration method. The water content ranged from 0-76 mole % and the oxygen content range was 0-100 mole % during the 20-250 hour exposure times. Preliminary results indicate that oxygen is not a key contributor at these temperatures and the following reaction is the primary volatile equation at all three temperatures: TiO 2 (s) + H2O (g) = TiO(OH)2 (g).

High Temperature Ultrasonic Transducers : Material Selection and Testing

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Bruno, Alessandro

2012-01-01

The task of my two-months internship was to test different materials to be used to build an high temperature transducer, to develop some prototypes and to test their performance, to assess the reliability of commercial product rated for such a temperature, as well as to collaborate in developing the signal processing code to measure the condensed water levels.

An ultra-high temperature testing instrument under oxidation environment up to 1800 °C.

PubMed

Cheng, Xiangmeng; Qu, Zhaoliang; He, Rujie; Ai, Shigang; Zhang, Rubing; Pei, Yongmao; Fang, Daining

2016-04-01

A new testing instrument was developed to measure the high-temperature constitutive relation and strength of materials under an oxidative environment up to 1800 °C. A high temperature electric resistance furnace was designed to provide a uniform temperature environment for the mechanical testing, and the temperature could vary from room temperature (RT) to 1800 °C. A set of semi-connected grips was designed to reduce the stress. The deformation of the specimen gauge section was measured by a high temperature extensometer. The measured results were acceptable compared with the results from the strain gauge method. Meanwhile, tensile testing of alumina was carried out at RT and 800 °C, and the specimens showed brittle fracture as expected. The obtained Young's modulus was in agreement with the reported value. In addition, tensile experiment of ZrB2-20%SiC ceramic was conducted at 1700 °C and the high-temperature tensile stress-strain curve was first obtained. Large plastic deformation up to 0.46% and the necking phenomenon were observed before the fracture of specimen. This instrument will provide a powerful research tool to study the high temperature mechanical property of materials under oxidation and is benefit for the engineering application of materials in aerospace field.

Mechanical Behavior of Glidcop Al-15 at High Temperature and Strain Rate

NASA Astrophysics Data System (ADS)

Scapin, M.; Peroni, L.; Fichera, C.

2014-05-01

Strain rate and temperature are variables of fundamental importance for the definition of the mechanical behavior of materials. In some elastic-plastic models, the effects, coming from these two quantities, are considered to act independently. This approach should, in some cases, allow to greatly simplify the experimental phase correlated to the parameter identification of the material model. Nevertheless, in several applications, the material is subjected to dynamic load at very high temperature, as, for example, in case of machining operation or high energy deposition on metals. In these cases, to consider the effect of strain rate and temperature decoupled could not be acceptable. In this perspective, in this work, a methodology for testing materials varying both strain rate and temperature was described and applied for the mechanical characterization of Glidcop Al-15, a copper-based composite reinforced with alumina dispersion, often used in nuclear applications. The tests at high strain rate were performed using the Hopkinson Bar setup for the direct tensile tests. The heating of the specimen was performed using an induction coil system and the temperature was controlled on the basis of signals from thermocouples directly welded on the specimen surface. Varying the strain rate, Glidcop Al-15 shows a moderate strain-rate sensitivity at room temperature, while it considerably increases at high temperature: material thermal softening and strain-rate hardening are strongly coupled. The experimental data were fitted using a modified formulation of the Zerilli-Armstrong model able to reproduce this kind of behavior with a good level of accuracy.

Assessment of Titanium Aluminide Alloys for High-Temperature Nuclear Structural Applications

NASA Astrophysics Data System (ADS)

Zhu, Hanliang; Wei, Tao; Carr, David; Harrison, Robert; Edwards, Lyndon; Hoffelner, Wolfgang; Seo, Dongyi; Maruyama, Kouichi

2012-12-01

Titanium aluminide (TiAl) alloys exhibit high specific strength, low density, good oxidation, corrosion, and creep resistance at elevated temperatures, making them good candidate materials for aerospace and automotive applications. TiAl alloys also show excellent radiation resistance and low neutron activation, and they can be developed to have various microstructures, allowing different combinations of properties for various extreme environments. Hence, TiAl alloys may be used in advanced nuclear systems as high-temperature structural materials. Moreover, TiAl alloys are good materials to be used for fundamental studies on microstructural effects on irradiation behavior of advanced nuclear structural materials. This article reviews the microstructure, creep, radiation, and oxidation properties of TiAl alloys in comparison with other nuclear structural materials to assess the potential of TiAl alloys as candidate structural materials for future nuclear applications.

Water Vapor Corrosion in EBC Constituent Materials

NASA Technical Reports Server (NTRS)

Kowalski, Benjamin; Fox, Dennis; Jacobson, Nathan S.

2017-01-01

Environmental Barrier Coating (EBC) materials are sought after to protect ceramic matrix composites (CMC) in high temperature turbine engines. CMCs are particularly susceptible to degradation from oxidation, Ca-Al-Mg-Silicate (CMAS), and water vapor during high temperature operation which necessitates the use of EBCs. However, the work presented here focuses on water vapor induced recession in EBC constituent materials. For example, in the presence of water vapor, silica will react to form Si(OH)4 (g) which will eventually corrode the material away. To investigate the recession rate in EBC constituent materials under high temperature water vapor conditions, thermal gravimetric analysis (TGA) is employed. The degradation process can then be modeled through a simple boundary layer expression. Ultimately, comparisons are made between various single- and poly-crystalline materials (e.g. TiO2, SiO2) against those found in literature.

Surface Effects and Challenges for Application of Piezoelectric Langasite Substrates in Surface Acoustic Wave Devices Caused by High Temperature Annealing under High Vacuum.

PubMed

Seifert, Marietta; Rane, Gayatri K; Kirbus, Benjamin; Menzel, Siegfried B; Gemming, Thomas

2015-12-19

Substrate materials that are high-temperature stable are essential for sensor devices which are applied at high temperatures. Although langasite is suggested as such a material, severe O and Ga diffusion into an O-affine deposited film was observed during annealing at high temperatures under vacuum conditions, leading to a damage of the metallization as well as a change of the properties of the substrate and finally to a failure of the device. Therefore, annealing of bare LGS (La 3 Ga 5 SiO 14 ) substrates at 800 ∘ C under high vacuum conditions is performed to analyze whether this pretreatment improves the suitability and stability of this material for high temperature applications in vacuum. To reveal the influence of the pretreatment on the subsequently deposited metallization, RuAl thin films are used as they are known to oxidize on LGS at high temperatures. A local study of the pretreated and metallized substrates using transmission electron microscopy reveals strong modification of the substrate surface. Micro cracks are visible. The composition of the substrate is strongly altered at those regions. Severe challenges for the application of LGS substrates under high-temperature vacuum conditions arise from these substrate damages, revealing that the pretreatment does not improve the applicability.

Non-contact Creep Resistance Measurement for Ultra-high temperature Materials

NASA Technical Reports Server (NTRS)

Hyers, Robert W.; Lee, Jonghuyn; Bradshaw, Richard C.; Rogers, Jan; Rathz, Thomas J.; Wall, James J.; Choo, Hahn; Liaw, Peter K.

2005-01-01

Continuing pressures for higher performance and efficiency in propulsion are driving ever more demanding needs for high-temperature materials. Some immediate applications in spaceflight include combustion chambers for advanced chemical rockets and turbomachinery for jet engines and power conversion in nuclear-electric propulsion. In the case of rockets, the combination of high stresses and high temperatures make the characterization of creep properties very important. Creep is even more important in the turbomachinery, where a long service life is an additional constraint. Some very high-temperature materials are being developed, including platinum group metals, carbides, borides, and silicides. But the measurement of creep properties at very high temperatures is itself problematic, because the testing instrument must operate at such high temperatures. Conventional techniques are limited to about 1700 C. A new, containerless technique for measuring creep deformation has been developed. This technique is based on electrostatic levitation (ESL) of a spherical sample, which is heated to the measurement temperature and rotated at a rate such that the centrifugal acceleration causes creep deformation. Creep of samples has been demonstrated at up to 2300 C in the ESL facility at NASA MSFC, while ESL itself has been applied at over 3000 C, and has no theoretical maximum temperature. The preliminary results and future directions of this NASA-funded research collaboration will be presented.

Plasma-assisted microwave processing of materials

NASA Technical Reports Server (NTRS)

Barmatz, Martin (Inventor); Jackson, Henry (Inventor); Ylin, Tzu-yuan (Inventor)

1998-01-01

A microwave plasma assisted method and system for heating and joining materials. The invention uses a microwave induced plasma to controllably preheat workpiece materials that are poorly microwave absorbing. The plasma preheats the workpiece to a temperature that improves the materials' ability to absorb microwave energy. The plasma is extinguished and microwave energy is able to volumetrically heat the workpiece. Localized heating of good microwave absorbing materials is done by shielding certain parts of the workpiece and igniting the plasma in the areas not shielded. Microwave induced plasma is also used to induce self-propagating high temperature synthesis (SHS) process for the joining of materials. Preferably, a microwave induced plasma preheats the material and then microwave energy ignites the center of the material, thereby causing a high temperature spherical wave front from the center outward.

High temperature lithium cells with solid polymer electrolytes

DOEpatents

Yang, Jin; Eitouni, Hany Basam; Singh, Mohit

2017-03-07

Electrochemical cells that use electrolytes made from new polymer compositions based on poly(2,6-dimethyl-1,4-phenylene oxide) and other high-softening-temperature polymers are disclosed. These materials have a microphase domain structure that has an ionically-conductive phase and a phase with good mechanical strength and a high softening temperature. In one arrangement, the structural block has a softening temperature of about 210.degree. C. These materials can be made with either homopolymers or with block copolymers. Such electrochemical cells can operate safely at higher temperatures than have been possible before, especially in lithium cells. The ionic conductivity of the electrolytes increases with increasing temperature.

Progress in advanced high temperature materials technology

NASA Technical Reports Server (NTRS)

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

1976-01-01

Significant progress has recently been made in many high temperature material categories pertinent to such applications by the industrial community. These include metal matrix composites, superalloys, directionally solidified eutectics, coatings, and ceramics. Each of these material categories is reviewed and the current state-of-the-art identified, including some assessment, when appropriate, of progress, problems, and future directions.

Trends in high pressure developments for new perspectives

NASA Astrophysics Data System (ADS)

Largeteau, Alain; Prakasam, Mythili

2018-06-01

Temperature and Pressure are two parameters in the universe, where pressure represents the largest scale in comparison to temperature. The design of high pressure equipment depends mainly on the media used which could be gas, liquid or solid and the objective could be synthesis of materials or in situ characterization. The development of new research fields requiring high pressure equipment which are currently in Bordeaux - France are based on the historical development of high pressure domain initiated by Professor Gerard DEMAZEAU and his team during the last half century, which is discussed here. The main concepts governing the effect of pressure on materials synthesis is by the combination of high pressure and high temperature which are described with apt examples. There is an upsurge in various technologies for strong development for the synthesis of materials to drive several possibilities, for example: to reach very high density to obtain optical ceramics (by conventional SPS), to diminish parameters (P, T, t) of synthesis (by HP-SPS), to sinter at low temperature thermal sensitive composition (by HyS), to consolidate porous materials (by FIP), to densify biocomposite with cold decontamination (by HHP) simultaneously, etc.

Polyimide/Glass Composite High-Temperature Insulation

NASA Technical Reports Server (NTRS)

Pater, Ruth H.; Vasquez, Peter; Chatlin, Richard L.; Smith, Donald L.; Skalski, Thomas J.; Johnson, Gary S.; Chu, Sang-Hyon

2009-01-01

Lightweight composites of RP46 polyimide and glass fibers have been found to be useful as extraordinarily fire-resistant electrical-insulation materials. RP46 is a polyimide of the polymerization of monomeric reactants (PMR) type, developed by NASA Langley Research Center. RP46 has properties that make it attractive for use in electrical insulation at high temperatures. These properties include high-temperature resistance, low relative permittivity, low dissipation factor, outstanding mechanical properties, and excellent resistance to moisture and chemicals. Moreover, RP46 contains no halogen or other toxic materials and when burned it does not produce toxic fume or gaseous materials. The U. S. Navy has been seeking lightweight, high-temperature-resistant electrical-insulation materials in a program directed toward reducing fire hazards and weights in ship electrical systems. To satisfy the requirements of this program, an electrical-insulation material must withstand a 3-hour gas-flame test at 1,600 F (about 871 C). Prior to the development reported here, RP46 was rated for use at temperatures from -150 to +700 F (about -101 to 371 C), and no polymeric product - not even RP46 - was expected to withstand the Navy 3-hour gas-flame test.

Characteristics of electroluminescence phenomenon in virgin and thermally aged LDPE

NASA Astrophysics Data System (ADS)

Bani, N. A.; Abdul-Malek, Z.; Ahmad, H.; Muhammad-Sukki, F.; Mas'ud, A. A.

2015-08-01

High voltage cable requires a good insulating material such as low density polyethylene (LDPE) to be able to operate efficiently in high voltage stresses and high temperature environment. However, any polymeric material will experience degradation after prolonged application of high electrical stresses or other extreme conditions. The continuous degradation will shorten the life of a cable therefore further understanding on the behaviour of the aged high voltage cable needs to be undertaken. This may be observed through electroluminescence (EL) measurement. EL occurs when a solid-state material is subjected to a high electrical field stress and associated with the generation of charge carriers within the polymeric material and that these charges can be produced by injection, de-trapping and field-dissociation at the metal-polymer interface. The behaviour of EL emission can be affected by applied field, applied frequency, ageing time, ageing temperature and types of materials, among others. This paper focuses on the measurement of EL emission of additive-free LDPE thermally aged at different temperature subjected to varying electric stresses at 50Hz. It can be observed that EL emission increases as voltage applied is increased. However, EL emission decreases as ageing temperature is increased for varying applied voltage.

High Curie temperature drive layer materials for ion-implanted magnetic bubble devices

NASA Technical Reports Server (NTRS)

Fratello, V. J.; Wolfe, R.; Blank, S. L.; Nelson, T. J.

1984-01-01

Ion implantation of bubble garnets can lower the Curie temperature by 70 C or more, thus limiting high temperature operation of devices with ion-implanted propagation patterns. Therefore, double-layer materials were made with a conventional 2-micron bubble storage layer capped by an ion-implantable drive layer of high Curie temperature, high magnetostriction material. Contiguous disk test patterns were implanted with varying doses of a typical triple implant. Quality of propagation was judged by quasistatic tests on 8-micron period major and minor loops. Variations of magnetization, uniaxial anisotropy, implant dose, and magnetostriction were investigated to ensure optimum flux matching, good charged wall coupling, and wide operating margins. The most successful drive layer compositions were in the systems (SmDyLuCa)3(FeSi)5O12 and (BiGdTmCa)3(FeSi)5O12 and had Curie temperatures 25-44 C higher than the storage layers.

Thermionic Properties of Carbon Based Nanomaterials Produced by Microhollow Cathode PECVD

NASA Technical Reports Server (NTRS)

Haase, John R.; Wolinksy, Jason J.; Bailey, Paul S.; George, Jeffrey A.; Go, David B.

2015-01-01

Thermionic emission is the process in which materials at sufficiently high temperature spontaneously emit electrons. This process occurs when electrons in a material gain sufficient thermal energy from heating to overcome the material's potential barrier, referred to as the work function. For most bulk materials very high temperatures (greater than 1500 K) are needed to produce appreciable emission. Carbon-based nanomaterials have shown significant promise as emission materials because of their low work functions, nanoscale geometry, and negative electron affinity. One method of producing these materials is through the process known as microhollow cathode PECVD. In a microhollow cathode plasma, high energy electrons oscillate at very high energies through the Pendel effect. These high energy electrons create numerous radical species and the technique has been shown to be an effective method of growing carbon based nanomaterials. In this work, we explore the thermionic emission properties of carbon based nanomaterials produced by microhollow cathode PECVD under a variety of synthesis conditions. Initial studies demonstrate measureable current at low temperatures (approximately 800 K) and work functions (approximately 3.3 eV) for these materials.

Some considerations for various positioning systems and their science capabilities

NASA Technical Reports Server (NTRS)

Rey, Charles A.; Merkley, D. R.; Danley, T. J.

1990-01-01

Containerless processing of materials at elevated temperatures is discussed with emphasis on high temperature chemistry, thermophysical properties, materials science, and materials processing. Acoustic and electromagnetic positioning of high temperature melts are discussed. Results from recent ground based experiments, including KC-135 testing of an acoustic levitator, are presented. Some current positioning technologies and the potential for enhancing them are considered. Further, a summary of these technologies and their science capabilities for the development of future experiments is given.

High-performance solid polymer electrolytes for lithium batteries operational at ambient temperature

NASA Astrophysics Data System (ADS)

Mindemark, Jonas; Sun, Bing; Törmä, Erik; Brandell, Daniel

2015-12-01

Incorporation of carbonate repeating units in a poly(ε-caprolactone) (PCL) backbone used as a host material in solid polymer electrolytes is found to not only suppress crystallinity in the polyester material, but also give higher ionic conductivity in a wide temperature range exceeding the melting point of PCL crystallites. Combined with high cation transference numbers, this electrolyte material has sufficient lithium transport properties to be used in battery cells that are operational at temperatures down to below 23 °C, thus clearly demonstrating the potential of using non-polyether electrolytes in high-performance all-solid lithium polymer batteries.

Advanced ceramic matrix composites for TPS

NASA Technical Reports Server (NTRS)

Rasky, Daniel J.

1992-01-01

Recent advances in ceramic matrix composite (CMC) technology provide considerable opportunity for application to future aircraft thermal protection system (TPS), providing materials with higher temperature capability, lower weight, and higher strength and stiffness than traditional materials. The Thermal Protection Material Branch at NASA Ames Research Center has been making significant progress in the development, characterization, and entry simulation (arc-jet) testing of new CMC's. This protection gives a general overview of the Ames Thermal Protection Materials Branch research activities, followed by more detailed descriptions of recent advances in very-high temperature Zr and Hf based ceramics, high temperature, high strength SiC matrix composites, and some activities in polymer precursors and ceramic coating processing. The presentation closes with a brief comparison of maximum heat flux capabilities of advanced TPS materials.

Processing of Ni30Pt20Ti50 High-Temperature Shape-Memory Alloy Into Thin Rod Demonstrated

NASA Technical Reports Server (NTRS)

Noebe, Ronald D.; Draper, Susan L.; Biles, Tiffany A.; Leonhardt, Todd

2005-01-01

High-temperature shape-memory alloys (HTSMAs) based on nickel-titanium (NiTi) with significant ternary additions of palladium (Pd), platinum (Pt), gold (Au), or hafnium (Hf) have been identified as potential high-temperature actuator materials for use up to 500 C. These materials provide an enabling technology for the development of "smart structures" used to control the noise, emissions, or efficiency of gas turbine engines. The demand for these high-temperature versions of conventional shape-memory alloys also has been growing in the automotive, process control, and energy industries. However these materials, including the NiPtTi alloys being developed at the NASA Glenn Research Center, will never find widespread acceptance unless they can be readily processed into useable forms.

Measurement of the properties of lossy materials inside a finite conducting cylinder

NASA Technical Reports Server (NTRS)

Dominek, A.; Park, A.; Caldecott, R.

1988-01-01

Broadband, swept frequency measurement techniques were investigated for the evaluation of the electrical performance of thin, high temperature material coatings. Reflections and transmission measurements using an HP8510B Network Analyzer were developed for an existing high temperature test rig at NASA Lewis Research Center. Reflection measurements will be the initial approach used due to fixture simplicity even though surface wave transmission measurements would be more sensitive. The minimum goal is to monitor the electrical change of the material's performance as a function of temperature. If possible, the materials constitutive parameters, epsilon and muon will be found.

Lateral Temperature-Gradient Method for High-Throughput Characterization of Material Processing by Millisecond Laser Annealing.

PubMed

Bell, Robert T; Jacobs, Alan G; Sorg, Victoria C; Jung, Byungki; Hill, Megan O; Treml, Benjamin E; Thompson, Michael O

2016-09-12

A high-throughput method for characterizing the temperature dependence of material properties following microsecond to millisecond thermal annealing, exploiting the temperature gradients created by a lateral gradient laser spike anneal (lgLSA), is presented. Laser scans generate spatial thermal gradients of up to 5 °C/μm with peak temperatures ranging from ambient to in excess of 1400 °C, limited only by laser power and materials thermal limits. Discrete spatial property measurements across the temperature gradient are then equivalent to independent measurements after varying temperature anneals. Accurate temperature calibrations, essential to quantitative analysis, are critical and methods for both peak temperature and spatial/temporal temperature profile characterization are presented. These include absolute temperature calibrations based on melting and thermal decomposition, and time-resolved profiles measured using platinum thermistors. A variety of spatially resolved measurement probes, ranging from point-like continuous profiling to large area sampling, are discussed. Examples from annealing of III-V semiconductors, CdSe quantum dots, low-κ dielectrics, and block copolymers are included to demonstrate the flexibility, high throughput, and precision of this technique.

Electrical and Thermal Transport Property Studies of High-Temperature Thermoelectric Materials.

DTIC Science & Technology

1984-12-15

Transport Property Studies of High-Temperature Thermoelectric Mateial 12. PERSONAL AUTHIOR(S) 113. TYPE OF REPORT 13b. TIME COVERED Ai DATE OF REPORtT (Yr...with an ABO(3 perovskite structure. Transport properties have been determined for various doping ele- ments and for different compositions. These data...THERMAL TRANSPORT PROPERTY STUDIES Unannounced [j OF HIGH-TEMPERATURE THERMOELECTRIC MATERIALS Justi±icI iou. CONTRACT F-49620-83-0109 DEF By-- Battelle

High performance structural laminate composite material for use to 1000.degree. F. and above, apparatus for and method of manufacturing same, and articles made with same

NASA Technical Reports Server (NTRS)

Seal, Ellis C. (Inventor); Biggs, Jr., Robert William (Inventor); Bodepudi, Venu Prasad (Inventor); Cranston, John A. (Inventor)

2003-01-01

A novel materials technology has been developed and demonstrated for providing a high modulus composite material for use to 1000.degree. F. and above. This material can be produced at 5-20% of the cost of refractory materials, and has higher structural properties. This technology successfully resolves the problem of thermal shock or ply lift, which limits traditional high temperature laminates (such as graphite/polyimide and graphite/phenolic) to temperatures of 550-650.degree. F. in thicker (0.25 and above) laminates. The technology disclosed herein is an enabling technology for the nose for the External Tank (ET) of the Space Shuttle, and has been shown to be capable of withstanding the severe environments encountered by the nose cone through wind tunnel testing, high temperature subcomponent testing, and full scale structural, dynamic, acoustic, and damage tolerance testing.

High-Temperature Treatments For Polyimide/Graphite Composite

NASA Technical Reports Server (NTRS)

Bowles, Kenneth J.; Lowell, Carl

1992-01-01

Combination of inert-gas heat treatment and coating with material impermeable by oxygen proposed to increase thermo-oxidative and high-temperature structural stabilities of composite materials made of graphite fibers in matrices of PMR-15 polyimide. Proposal directed toward development of lightweight matrix/fiber composites for use in aircraft engines, wherein composites exposed to maximum operating temperatures between 371 and 427 degrees C.

High-temperature Raman spectroscopy of solid oxide fuel cell materials and processes.

PubMed

Pomfret, Michael B; Owrutsky, Jeffrey C; Walker, Robert A

2006-09-07

Chemical and material processes occurring in high temperature environments are difficult to quantify due to a lack of experimental methods that can probe directly the species present. In this letter, Raman spectroscopy is shown to be capable of identifying in-situ and noninvasively changes in material properties as well as the formation and disappearance of molecular species on surfaces at temperatures of 715 degrees C. The material, yttria-stabilized zirconia or YSZ, and the molecular species, Ni/NiO and nanocrystalline graphite, factor prominently in the chemistry of solid oxide fuel cells (SOFCs). Experiments demonstrate the ability of Raman spectroscopy to follow reversible oxidation/reduction kinetics of Ni/NiO as well as the rate of carbon disappearance when graphite, formed in-situ, is exposed to a weakly oxidizing atmosphere. In addition, the Raman active phonon mode of YSZ shows a temperature dependent shift that correlates closely with the expansion of the lattice parameter, thus providing a convenient internal diagnostic for identifying thermal gradients in high temperature systems. These findings provide direct insight into processes likely to occur in operational SOFCs and motivate the use of in-situ Raman spectroscopy to follow chemical processes in these high-temperature, electrochemically active environments.

Simultaneous thermal analysis and thermodilatometry of hybrid fiber reinforced UHPC

NASA Astrophysics Data System (ADS)

Scheinherrová, Lenka; Fořt, Jan; Pavlík, Zbyšek; Černý, Robert

2017-07-01

Development of concrete technology and the availability of variety of materials such as silica fume, mineral microfillers and high-range water-reducing admixtures make possible to produce Ultra-High Performance Concrete (UHPC) with compressive strength higher than 160 MPa. However, UHPC is prone to spall under high temperatures what limits its use for special applications only, such as offshore and marine structures, industrial floors, security barriers etc. The spalling is caused by the thermal stresses due to the temperature gradient during heating, and by the splitting force owing to the release of water vapour. Hybrid fibre reinforcement based on combination of steel and polymer fibres is generally accepted by concrete community as a functional solution preventing spalling. In this way, Ultra-High Performance Fibre Reinforced Concrete (UHPFRC) is produced possessing high mechanical strength, durability and resistance to water and salt ingress. Since UHPFRC find use in construction industry in tunnel linings, precast tunnel segments, and high-rise buildings, its behaviour during the high-temperature exposure and its residual parameters are of the particular importance. On this account, Simultaneous Thermal Analysis (STA) and Thermodilatometry Analysis (TDA) were done in the paper to identify the structural and chemical changes in UHPFRC during its high-temperature load. Based on the experimental results, several physical and chemical processes that studied material underwent at high-temperatures were recognized. The obtained data revealed changes in the composition of the studied material and allowed identification of critical temperatures for material damage.

Development of high temperature fasteners using directionally solidified eutectic alloys

NASA Technical Reports Server (NTRS)

George, F. D.

1972-01-01

The suitability of the eutectics for high temperature fasteners was investigated. Material properties were determined as a function of temperature, and included shear parallel and perpendicular to the growth direction and torsion parallel to it. Techniques for fabricating typical fastener shapes included grinding, creep forming, and direct casting. Both lamellar Ni3Al-Ni3Nb and fibrous (Co,Cr,Al)-(Cr,Co)7C3 alloys showed promise as candidate materials for high temperature fastener applications. A brief evaluation of the performance of the best fabricated fastener design was made.

Metals and Ceramics Division progress report for period ending December 31, 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Craig, D.F.; Weir, J.R. Jr.

1993-04-01

This report provides a brief overview of the activities and accomplishments of the division, whose purpose is to provide technical support, primarily in the area of high-temperature materials, for the various technologies being developed by US DOE. Activities range from basic research to industrial research and technology transfer. The division (and the report) is divided into the following: Engineering materials, high-temperature materials, materials science, ceramics, nuclear fuel materials, program activities, collaborative research facilities and technology transfer, and educational programs.

Process and apparatus for preparing textured crystalline materials using anisotropy in the paramagnetic susceptibility

DOEpatents

Holloway, Aleksey

1992-01-07

The present invention discloses a process and apparatus for forming textures in materials. The process comprises heating a material having an anisotropy in the paramagnetic or diamagnetic susceptibility within a magnetic field. The material is heated to a temperature approaching its melting point while a magnetic field of at least 10.sup.4 Oe is simultaneously applied. The process and apparatus produce highly textured bulk and elongated materials with high current densities below critical superconducting temperatures.

Method and composition for improving flux pinning and critical current in superconductors

DOEpatents

Morris, Donald E.

1995-01-01

Superconducting materials and methods of forming superconducting materials are disclosed. Highly oxidized superconductors are heated at a relatively high temperature so as to release oxygen, which migrates out of the material, and form a non-superconducting phase which does not diffuse out of grains of the material. The material is then reoxidized at a lower temperature, leaving the non-superconducting inclusions inside a superconducting phase. The non-superconducting inclusions act as pinning centers in the superconductor, increasing the critical current thereof.

Method and composition for improving flux pinning and critical current in superconductors

DOEpatents

Morris, D.E.

1995-07-04

Superconducting materials and methods of forming superconducting materials are disclosed. Highly oxidized superconductors are heated at a relatively high temperature so as to release oxygen, which migrates out of the material, and form a non-superconducting phase which does not diffuse out of grains of the material. The material is then reoxidized at a lower temperature, leaving the non-superconducting inclusions inside a superconducting phase. The non-superconducting inclusions act as pinning centers in the superconductor, increasing the critical current thereof. 14 figs.

Process and apparatus for preparing textured crystalline materials using anisotropy in the paramagnetic susceptibility

DOEpatents

Holloway, A.

1992-01-07

The present invention discloses a process and apparatus for forming textures in materials. The process comprises heating a material having an anisotropy in the paramagnetic or diamagnetic susceptibility within a magnetic field. The material is heated to a temperature approaching its melting point while a magnetic field of at least 10[sup 4]Oe is simultaneously applied. The process and apparatus produce highly textured bulk and elongated materials with high current densities below critical superconducting temperatures. 6 figs.

Wide range scaling laws for radiation driven shock speed, wall albedo and ablation parameters for high-Z materials

NASA Astrophysics Data System (ADS)

Mishra, Gaurav; Ghosh, Karabi; Ray, Aditi; Gupta, N. K.

2018-06-01

Radiation hydrodynamic (RHD) simulations for four different potential high-Z hohlraum materials, namely Tungsten (W), Gold (Au), Lead (Pb), and Uranium (U) are performed in order to investigate their performance with respect to x-ray absorption, re-emission and ablation properties, when irradiated by constant temperature drives. A universal functional form is derived for estimating time dependent wall albedo for high-Z materials. Among the high-Z materials studied, it is observed that for a fixed simulation time the albedo is maximum for Au below 250 eV, whereas it is maximum for U above 250 eV. New scaling laws for shock speed vs drive temperature, applicable over a wide temperature range of 100 eV to 500 eV, are proposed based on the physics of x-ray driven stationary ablation. The resulting scaling relation for a reference material Aluminium (Al), shows good agreement with that of Kauffman's power law for temperatures ranging from 100 eV to 275 eV. New scaling relations are also obtained for temperature dependent mass ablation rate and ablation pressure, through RHD simulation. Finally, our study reveals that for temperatures above 250 eV, U serves as a better hohlraum material since it offers maximum re-emission for x-rays along with comparable mass ablation rate. Nevertheless, traditional choice, Au works well for temperatures below 250 eV. Besides inertial confinement fusion (ICF), the new scaling relations may find its application in view-factor codes, which generally ignore atomic physics calculations of opacities and emissivities, details of laser-plasma interaction and hydrodynamic motions.

Graphene, a material for high temperature devices – intrinsic carrier density, carrier drift velocity, and lattice energy

PubMed Central

Yin, Yan; Cheng, Zengguang; Wang, Li; Jin, Kuijuan; Wang, Wenzhong

2014-01-01

Heat has always been a killing matter for traditional semiconductor machines. The underlining physical reason is that the intrinsic carrier density of a device made from a traditional semiconductor material increases very fast with a rising temperature. Once reaching a temperature, the density surpasses the chemical doping or gating effect, any p-n junction or transistor made from the semiconductor will fail to function. Here, we measure the intrinsic Fermi level (|EF| = 2.93 kBT) or intrinsic carrier density (nin = 3.87 × 106 cm−2K−2·T2), carrier drift velocity, and G mode phonon energy of graphene devices and their temperature dependencies up to 2400 K. Our results show intrinsic carrier density of graphene is an order of magnitude less sensitive to temperature than those of Si or Ge, and reveal the great potentials of graphene as a material for high temperature devices. We also observe a linear decline of saturation drift velocity with increasing temperature, and identify the temperature coefficients of the intrinsic G mode phonon energy. Above knowledge is vital in understanding the physical phenomena of graphene under high power or high temperature. PMID:25044003

Nickel-Graphite Composite Compliant Interface and/or Hot Shoe Material

NASA Technical Reports Server (NTRS)

Firdosy, Samad A.; Chun-Yip Li, Billy; Ravi, Vilupanur A.; Fleurial, Jean-Pierre; Caillat, Thierry; Anjunyan, Harut

2013-01-01

Next-generation high-temperature thermoelectric-power-generating devices will employ segmented architectures and will have to reliably withstand thermally induced mechanical stresses produced during component fabrication, device assembly, and operation. Thermoelectric materials have typically poor mechanical strength, exhibit brittle behavior, and possess a wide range of coefficient of thermal expansion (CTE) values. As a result, the direct bonding at elevated temperatures of these materials to each other to produce segmented leg components is difficult, and often results in localized microcracking at interfaces and mec hanical failure due to the stresses that arise from the CTE mismatch between the various materials. Even in the absence of full mechanical failure, degraded interfaces can lead to increased electrical and thermal resistances, which adversely impact conversion efficiency and power output. The proposed solution is the insertion of a mechanically compliant layer, with high electrical and thermal conductivity, between the low- and high-temperature segments to relieve thermomechanical stresses during device fabrication and operation. This composite material can be used as a stress-relieving layer between the thermoelectric segments and/or between a thermoelectric segment and a hot- or cold-side interconnect material. The material also can be used as a compliant hot shoe. Nickel-coated graphite powders were hot-pressed to form a nickel-graphite composite material. A freestanding thermoelectric segmented leg was fabricated by brazing the compliant pad layer between the high-temperature p- Zintl and low-temperature p-SKD TE segments using Cu-Ag braze foils. The segmented leg stack was heated in vacuum under a compressive load to achieve bonding. The novelty of the innovation is the use of composite material that re duces the thermomechanical stresses en - countered in the construction of high-efficiency, high-temperature therm - o-electric devices. The compliant pad enables the bonding of dissimilar thermoelectric materials while maintaining the desired electrical and thermal properties essential for efficient device operation. The modulus, CTE, electrical, and thermal conductances of the composite can be controlled by varying the ratio of nickel to graphite.

ACBC to Balcite: Bioinspired Synthesis of a Highly Substituted High-Temperature Phase from an Amorphous Precursor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whittaker, Michael L.; Joester, Derk

2017-04-28

Energy-efficient synthesis of materials locked in compositional and structural states far from equilibrium remains a challenging goal, yet biomineralizing organisms routinely assemble such materials with sophisticated designs and advanced functional properties, often using amorphous precursors. However, incorporation of organics limits the useful temperature range of these materials. Herein, the bioinspired synthesis of a highly supersaturated calcite (Ca0.5Ba0.5CO3) called balcite is reported, at mild conditions and using an amorphous calcium–barium carbonate (ACBC) (Ca1- x Ba x CO3·1.2H2O) precursor. Balcite not only contains 50 times more barium than the solubility limit in calcite but also displays the rotational disorder on carbonate sitesmore » that is typical for high-temperature calcite. It is significantly harder (30%) and less stiff than calcite, and retains these properties after heating to elevated temperatures. Analysis of balcite local order suggests that it may require the formation of the ACBC precursor and could therefore be an example of nonclassical nucleation. These findings demonstrate that amorphous precursor pathways are powerfully enabling and provide unprecedented access to materials far from equilibrium, including high-temperature modifications by room-temperature synthesis.« less

Mechanical Testing of PMCs under Simulated Rapid Heat-Up Propulsion Environments. II; In-Plane Compressive Behavior

NASA Technical Reports Server (NTRS)

Stokes, Eric H.; Shin, E. Eugene; Sutter, James K.

2003-01-01

Carbon fiber thermoset polymer matrix composites (PMC) with high temperature polyimide based in-situ polymerized monomer reactant (PMR) resin has been used for some time in applications which can see temperatures up to 550 F. Currently, graphite fiber PMR based composites are used in several aircraft engine components including the outer bypass duct for the GE F-404, exit flaps for the P&W F-100-229, and the core cowl for the GE/Snecma CF6-80A3. Newer formulations, including PMR-II-50 are being investigated as potential weight reduction replacements of various metallic components in next generation high performance propulsion rocket engines that can see temperatures which exceed 550 F. Extensive FEM thermal modeling indicates that these components are exposed to rapid heat-up rates (up to -200 F/sec) and to a maximum temperature of around 600 F. Even though the predicted maximum part temperatures were within the capability of PW-II-50, the rapid heat-up causes significant through-thickness thermal gradients in the composite part and even more unstable states when combined with moisture. Designing composite parts for such extreme service environments will require accurate measurement of intrinsic and transient mechanical properties and the hygrothermal performance of these materials under more realistic use conditions. The mechanical properties of polymers degrade when exposed to elevated temperatures even in the absence of gaseous oxygen. Accurate mechanical characterization of the material is necessary in order to reduce system weight while providing sufficient factors of safety. Historically, the testing of PMCs at elevated temperatures has been plagued by the antagonism between two factors. First, moisture has been shown to profoundly affect the mechanical response of these materials at temperatures above their glass transition temperature while concurrently lowering the material's Tg. Moisture phenomena is due to one or a combination of three effects, i.e., plastization of polymeric material by water, the internal pressure generated by the volatilization of water at elevated temperatures, and hydrolytic chemical decomposition. However, moisture is lost from the material at increasing rates as temperature increases. Second, because PMCs are good thermal insulators, when they are externally heated at even mild rates large thermal gradients can develop within the material. At temperatures where a material property changes rapidly with temperature the presence of a large thermal gradient is unacceptable for intrinsic property characterization purposes. Therefore, long hold times are required to establish isothermal conditions. However, in the service environments high-heating-rates, high temperatures, high-loading rates are simultaneous present along with residual moisture. In order to capture the effects of moisture on the material, holding at- temperature until isothermal conditions are reached is unacceptable particularly in materials with small physical dimensions. Thus, the effects due to moisture on the composite's mechanical characteristics, ie., their so-called analog response, may be instructive. One approach employed in this program was rapid heat-up (approx. 200 F/sec.) and loading of both dry and wet in-plane compressive specimens to examine the effects of moisture on this resin dominated mechanical property of the material.

Boron-containing organosilane polymers and ceramic materials thereof

NASA Technical Reports Server (NTRS)

Riccitiello, Salvatore R. (Inventor); Hsu, Ming-Ta S. (Inventor); Chen, Timothy S. (Inventor)

1988-01-01

The present invention relates to organic silicon-boron polymers which upon pyrolysis produce high-temperature ceramic materials. More particularly, it relates to the polyorganoborosilanes containing -Si-B- bonds which generate high-temperature ceramic materials (e.g., SiC, SiB4, B4C) upon thermal degradation. The process for preparing these organic silicon-boron polymer precursors are also part of the invention.

Chimeric Plastics : a new class of thermoplastic

NASA Astrophysics Data System (ADS)

Sonnenschein, Mark

A new class of thermoplastics (dubbed ``Chimerics'') is described that exhibits a high temperature glass transition followed by high performance elastomer properties, prior to melting. These transparent materials are comprised of co-continuous phase-separated block copolymers. One block is an amorphous glass with a high glass transition temperature, and the second is a higher temperature phase transition block creating virtual thermoreversible crosslinks. The material properties are highly influenced by phase separation on the order of 10-30 nanometers. At lower temperatures the polymer reflects the sum of the block copolymer properties. As the amorphous phase glass transition is exceeded, the virtual crosslinks of the higher temperature second phase dominate the plastic properties, resulting in rubber-like elasticity.

The electrical properties and glass transition of some dental materials after temperature exposure.

PubMed

Marcinkowska, Agnieszka; Gauza-Wlodarczyk, Marlena; Kubisz, Leszek; Hedzelek, Wieslaw

2017-10-17

The physicochemical properties of dental materials will remain stable only when these materials in question are resistant to the changes in the oral cavity. The oral environment is subject to large temperature variations. The aim of the study was the assessment of electrical properties and glass transition of some dental materials after temperature exposure. Composite materials, compomers, materials for temporary prosthetic replacement and resin-based pit and fissure sealants were used in the study. The method used was electric conductivity of materials under changing temperature. The order of materials presenting the best characteristics for insulators was as follows: materials for temporary prosthetic replacement, resin-based pit and fissure sealants, composites, and compomers. Thanks to comparisons made between graphs during I and II heating run, the method could be used to observe changes in the heated material and determine whether the changes observed are reversible or permanent. The graphs also provided temperature values which contain information on glass transition during heating. In the oral cavity the effect of the constant temperature stimulus influences maturity of dental materials and improves their properties. But high temperatures over glass transition temperature can cause irreversible deformation and changes of the materials properties, even in a short time.

Synthesis, purification and bulk crystal growth of radiation detector materials using melt growth technique

NASA Astrophysics Data System (ADS)

Surabhi, Raja Rahul Reddy

In the past decade, there has been new and increased usage of radiation-detection technologies for applications in homeland security, non-proliferation, and national defense. Most of these applications require a portable device with high gamma-ray energy resolution and detection efficiency, compact size, room-temperature operation, and low cost. Consequently, there is a renewed understanding of the material limitations for these technologies and a great demand to develop next-generation radiation-detection materials that can operate at room temperature. Mercuric iodide (HgI2), Lead iodide (PbI2), and CdZnTe (CZT) are the current leading candidates for radiation detector applications. This is because of their high atomic number and large band gap that makes them particularly well suited for fabrication of high resolution and high efficiency compact devices. PbI2 is a promising material for room temperature nuclear radiation detectors, characterized by its wide band gap (EG=2.32eV) and high-density (rho=6.2g/cm3). It has been reported that PbI2 crystal detectors are able to detect gamma-ray in the range of 1KeV-1MeV, with good energy resolution. However, PbI 2 detectors have not been studied in detail because of non-availability of high quality single crystals. This study presents the synthesis, purification, growth and characterization of PbI2 single crystals grown. In this research, solid-state synthesis technique has been utilized for obtaining PbI2 as a starting material. For the first time, a unique low-temperature purification technique has been developed to obtain high-purity starting material. The crystals were grown using 2-zone Bridgman-Stockbarger (B.S) technique wherein growth rate and temperature gradient at the solid-liquid interface were optimized. Single crystals of PbI2 were successfully grown in quartz glass ampoule under different growth conditions. Material purity was determined by measuring the elemental concentration using the Inductively coupled plasma-optical emission spectroscopy (ICP-OES). ICP-OES is utilized for estimating impurities present in the low-temperature purified material, zone refined material and melt grown PbI2 crystals. The zone-refined material contains no traceable amounts of impurities, whereas the low-temperature purified material and melt grown PbI2 crystals show very low concentration of K (potassium) and Na (sodium) impurities. Crystal characterization has been performed for determining optical properties by UV-VIS spectroscopy. The energy band gap (EG) is an important parameter for materials used for room temperature gamma-ray detector applications. The absorption peak at 530nm is a characteristic of PbI2 and corresponds to the onset of the transitions from the valence band to the exciton level. From this absorption spectrum the calculated indirect band gap of PbI 2 was 2.33+/-0.025 eV at room temperature. For measuring the electrical properties (Dielectric and I-V characteristics) of the crystal, Ag (silver) contacts are applied to both sides of the sample. Dielectric analysis on melt grown PbI2 showed that space charge polarization was dominant at lower frequencies but stabilizes at higher frequencies over different operating temperatures. On the other hand, dielectric analysis for zone-refined material space charge polarization was constant over the operating range resulting in fewer lattice defects. Therefore the low temperature purified material followed by zone-refined purification provides detector grade material with fewer lattice defects. The measured electrical resistivity for melt grown PbI2 and zone-refined material are 3.185 x 10 10 O-cm and 0.754 x 109 O-cm at room temperature along (001) plane respectively.

Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

NASA Technical Reports Server (NTRS)

Cox, Sarah; Lui, Donovan; Gou, Jihua

2014-01-01

The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed, to be cured, and be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000degC. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200degC, -SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Testing for this included thermal and mechanical testing per ASTM standard tests.

The low-temperature scintillation properties of bismuth germanate and its application to high-energy gamma radiation imaging devices.

PubMed

Piltingsrud, H V

1979-12-01

Bismuth germanate is a scintillation material with very high z, and high density (7.13 g/cm3). It is a rugged, nonhygroscopic, crystalline material with room-temperature scintillation properties described by previous investigators as having a light yield approximately 8% of that of NaI(Tl), emission peak at approximately 480 nm, decay constant of 0.3 microsec, and energy resolution congruent to 15% (FWHM) for Cs-137 gamma radiations. These properties make it an excellent candidate for applications involving the detection of high-energy gamma photons and positron annihilation radiation, particularly when good spatial resolution is desired. At room temperature, however, the application of this material is somewhat limited by low light output and poor energy resolution. This paper presents new data on the scintillation properties of bismuth germanate as a function of temperature from -- 196 degrees C to j0 degrees C. Low-temperature use of the material is shown to greatly improve its light yield and energy resolution. The implications of this work to the design of imaging devices for high-energy radiation in health physics and nuclear medicine are discussed.

High performance polymer development

NASA Technical Reports Server (NTRS)

Hergenrother, Paul M.

1991-01-01

The term high performance as applied to polymers is generally associated with polymers that operate at high temperatures. High performance is used to describe polymers that perform at temperatures of 177 C or higher. In addition to temperature, other factors obviously influence the performance of polymers such as thermal cycling, stress level, and environmental effects. Some recent developments at NASA Langley in polyimides, poly(arylene ethers), and acetylenic terminated materials are discussed. The high performance/high temperature polymers discussed are representative of the type of work underway at NASA Langley Research Center. Further improvement in these materials as well as the development of new polymers will provide technology to help meet NASA future needs in high performance/high temperature applications. In addition, because of the combination of properties offered by many of these polymers, they should find use in many other applications.

Assessment of the State of the Art of Ultra High Temperature Ceramics

NASA Technical Reports Server (NTRS)

Johnson, Sylvia; Gasch, Matt; Stackpoole, Mairead

2009-01-01

Ultra High Temperature Ceramics (UHTCs) are a family of materials that includes the borides, carbides and nitrides of hafnium-, zirconium- and titanium-based systems. UHTCs are famous for possessing some of the highest melting points of known materials. In addition, they are very hard, have good wear resistance, mechanical strength, and relatively high thermal conductivities (compared to other ceramic materials). Because of these attributes, UHTCs are ideal for thermal protection systems, especially those that require chemical and structural stability at extremely high operating temperatures. UHTCs have the potential to revolutionize the aerospace industry by enabling the development of sharp hypersonic vehicles or atmospheric entry probes capable of the most extreme entry conditions.

Development of processing techniques for advanced thermal protection materials

NASA Technical Reports Server (NTRS)

Selvaduray, Guna S.

1995-01-01

The main purpose of this work has been in the development and characterization of materials for high temperature applications. Thermal Protection Systems (TPS) are constantly being tested, and evaluated for increased thermal shock resistance, high temperature dimensional stability, and tolerance to environmental effects. Materials development was carried out through the use of many different instruments and methods, ranging from extensive elemental analysis to physical attributes testing. The six main focus areas include: (1) protective coatings for carbon/carbon composites; (2) TPS material characterization; (3) improved waterproofing for TPS; (4) modified ceramic insulation for bone implants; (5) improved durability ceramic insulation blankets; and (6) ultra-high temperature ceramics. This report describes the progress made in these research areas during this contract period.

Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

NASA Technical Reports Server (NTRS)

Cox, Sarah B.; Lui, Donovan; Gou, Jihua

2014-01-01

The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, which allows a shape to be formed prior to the cure, and is then pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Basalt fibers are used for the reinforcement in the composite system. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material.

High Temperature Corrosion Problem of Boiler Components in presence of Sulfur and Alkali based Fuels

NASA Astrophysics Data System (ADS)

Ghosh, Debashis; Mitra, Swapan Kumar

2011-04-01

Material degradation and ageing is of particular concern for fossil fuel fired power plant components. New techniques/approaches have been explored in recent years for Residual Life assessment of aged components and material degradation due to different damage mechanism like creep, fatigue, corrosion and erosion etc. Apart from the creep, the high temperature corrosion problem in a fossil fuel fired boiler is a matter of great concern if the fuel contains sulfur, chlorine sodium, potassium and vanadium etc. This paper discusses the material degradation due to high temperature corrosion in different critical components of boiler like water wall, superheater and reheater tubes and also remedial measures to avoid the premature failure. This paper also high lights the Residual Life Assessment (RLA) methodology of the components based on high temperature fireside corrosion. of different critical components of boiler.

Ceramic materials under high temperature heat transfer conditions

NASA Astrophysics Data System (ADS)

Mittenbühler, A.; Jung, J.

1990-04-01

Ceramic materials for application in a High-Temperature Reactor coupled with the steam gasification of coal were investigated. The study concentrated on the hot gas duct and their thermal insulation. Materials examined for the inner lining of the tubes were graphite, carbon fibre reinforced carbon and amorphous silica, while fibres, porous alumina and bonded alumina fibres were tested as insulating materials. During material investigations qualification was performed on samples and in component tests. For two carbon fibre reinforced carbon qualities with different graphitizing temperatures, the bending strength was determined as a function of volume corrosion. Devitrification of amorphous silica can be tolerated up to operating temperatures of about 950°C. The resilience of fibre materials depends on the Al2O3/ SiO2 ratio. It decreases according to the different fibre composition with increasing temperature and limits the maximum operating temperature for long term operation. The porous hollow spherical corundum inserted in the form of bricks fulfilled the thermal shock and mechanical requirements but led to an insulation exhibiting gaps in component tests. An advanced insulation on the basis of bonded alumina fibre showed a quasi-elastic material behaviour. Resistance to abrasion was achieved with a protective ceramic coating. The different materials and design concepts are compared and the results provide a good solution for the project.

High Temperature Permeability of Carbon Cloth Phenolic Composite

NASA Technical Reports Server (NTRS)

Park, O. Y.; Lawrence, T. W.

2003-01-01

The carbon fiber phenolic resin composite material used for the RSRM nozzle insulator occasionally experiences problems during operation from pocketing or spalling-like erosion and lifting of plies into the char layer. This phenomenon can be better understood if the permeability of the material at elevated temperatures is well defined. This paper describes an experimental approach to determining high temperature permeability of the carbon phenolic material used as the RSRM nozzle liner material. Two different approaches were conducted independently using disk and bar type specimens with the designed permeability apparatus. The principle of the apparatus was to subject a test specimen to a high pressure differential and a heat supply and to monitor both the pressure and temperature variations resulting from gas penetration through the permeable wall between the two chambers. The bar types, especially designed to eliminate sealing difficulties at a high temperature environment, were directly exposed to real time temperature elevation from 22 C to 260 C during the test period. The disk types were pre-heat treated up to 300 C for 8 hours and cooled to room temperature before testing. Nonlinear variation of downstream pressure at a certain temperature range implied moisture release and matrix pyrolysis. Permeability was calculated using a semi-numerical model of quasi-steady state. The test results and the numerical model are discussed in the paper.

Weldability, strength, and high temperature stability of chemically vapor deposited tungsten

NASA Technical Reports Server (NTRS)

Bryant, W. A.

1972-01-01

Three types of CVD tungsten (fluoride-produced, chloride-produced and the combination of the two which is termed duplex) were evaluated to determine their weldability, high temperature strength and structural stability during 5000 hour exposure to temperatures of 1540 C and 1700 C. Each type of CVD tungsten could be successfully electron beam welded but the results for the chloride product were not as satisfactory as those of the other two materials. The high temperature strength behavior of the three materials did not differ greatly. However a large difference was noted for the grain growth behavior of the two basic CVD tungsten materials. Fluoride tungsten was found to be relatively stable while for the most part the grain size of chloride tungsten increased appreciably. The examination of freshly fractured surfaces with a scanning electron microscope revealed numerous bubbles in the fluoride material following its exposure to 1700 C for 5000 hours. Less severe thermal treatments produced relatively few bubbles in this material. Only at certain locations within the chloride material associated with the interruption of tungsten were bubbles noted.

ZnO core spike particles and nano-networks and their wide range of applications

NASA Astrophysics Data System (ADS)

Wille, S.; Mishra, Y. K.; Gedamu, D.; Kaps, S.; Jin, X.; Koschine, T.; Bathnagar, A.; Adelung, R.

2011-05-01

In our approach we are producing a polymer composite material with ZnO core spike particles as concave fillers. The core spike particles are synthesized by a high throughput method. Using PDMS (Polydimethylsiloxane) as a matrix material the core spike particles achieve not only a high mechanical reinforcement but also influence other material properties in a very interesting way, making such a composite very interesting for a wide range of applications. In a very similar synthesis route a nanoscopic ZnO-network is produced. As a ceramic this network can withstand high temperatures like 1300 K. In addition this material is quite elastic. To find a material with these two properties is a really difficult task, as polymers tend to decompose already at lower temperatures and metals melt. Especially under ambient conditions, often oxygen creates a problem for metals at these temperatures. If this material is at the same time a semiconductor, it has a high potential as a multifunctional material. Ceramic or classical semiconductors like III-V or IIVI type are high temperature stable, but typically brittle. This is different on the nanoscale. Even semiconductor wires like silicon with a very small diameter do not easily built up enough stress that leads to a failure while being bent, because in a first order approximation the maximum stress of a fiber scales with its diameter.

Engineered flux-pinning centers in BSCCO TBCCO and YBCO superconductors

DOEpatents

Goretta, Kenneth C.; Lanagan, Michael T.; Miller, Dean J.; Sengupta, Suvankar; Parker, John C.; Hu, Jieguang; Balachandran, Uthamalingam; Siegel, Richard W.; Shi, Donglu

1999-01-01

A method of preparing a high temperature superconductor. A method of preparing a superconductor includes providing a powdered high temperature superconductor and a nanophase material. These components are combined to form a solid compacted mass with the material disposed in the polycrystalline high temperature superconductor. This combined mixture is rapidly heated, forming a dispersion of nanophase size particles without a eutectic reaction. These nanophase particles can have a flat plate or columnar type morphology.

Optimization of Multilayer Laminated Film and Absorbent of Vacuum Insulation Panel for Use at High Temperature

NASA Astrophysics Data System (ADS)

Araki, Kuninari; Echigoya, Wataru; Tsuruga, Toshimitsu; Kamoto, Daigorou; Matsuoka, Shin-Ichi

For the energy saving regulation and larger capacity, Vacuum Insulation Panel (VIP) has been used in refrigerators with urethane foam in recent years. VIP for low temperature is constructed by laminated plastic film, using heat welding of each neighboring part for keeping vacuum, so that the performance decrement is very large under high temperature. But recently high efficiency insulation material is desired for high temperature water holding devices (automatic vending machine, heat pump water heater, electric hot-water pot water, etc.), and we especially focused on cost and ability of the laminated plastic film and absorbent for high temperature VIP. We measured the heatproof temperature of plastic films and checked the amount of water vapor and out coming gas on temperature-programmed adsorption in absorbent. These results suggest the suitable laminated film and absorbent system for VIP use at high temperature, and the long-term reliability was evaluated by measuring thermal conductivity of high temperature. As a result it was found that high-retort pouch of CPP (cast polypropylene film) and adding of aluminum coating are the most suitable materials for use in the welded layers of high-temperature VIPs (105°C).

How Molecular Structure Affects Mechanical Properties of an Advanced Polymer

NASA Technical Reports Server (NTRS)

Nicholson, Lee M.; Whitley, Karen S.; Gates, Thomas S.; Hinkley, Jeffrey A.

2000-01-01

density was performed over a range of temperatures below the glass transition temperature. The physical characterization, elastic properties and notched tensile strength all as a function of molecular weight and test temperature were determined. For the uncrosslinked SI material, it was shown that notched tensile strength is a strong function of both temperature and molecular weight, whereas stiffness is only a strong function of temperature. For the crosslinked PETI-SI material, it was shown that the effect of crosslinking significantly enhances the mechanical performance of the low molecular weight material; comparable to that exhibited by the high molecular weight material.

Advanced Electrical Materials and Components Being Developed

NASA Technical Reports Server (NTRS)

Schwarze, Gene E.

2004-01-01

All aerospace systems require power management and distribution (PMAD) between the energy and power source and the loads. The PMAD subsystem can be broadly described as the conditioning and control of unregulated power from the energy source and its transmission to a power bus for distribution to the intended loads. All power and control circuits for PMAD require electrical components for switching, energy storage, voltage-to-current transformation, filtering, regulation, protection, and isolation. Advanced electrical materials and component development technology is a key technology to increasing the power density, efficiency, reliability, and operating temperature of the PMAD. The primary means to develop advanced electrical components is to develop new and/or significantly improved electronic materials for capacitors, magnetic components, and semiconductor switches and diodes. The next important step is to develop the processing techniques to fabricate electrical and electronic components that exceed the specifications of presently available state-of-the-art components. The NASA Glenn Research Center's advanced electrical materials and component development technology task is focused on the following three areas: 1) New and/or improved dielectric materials for the development of power capacitors with increased capacitance volumetric efficiency, energy density, and operating temperature; 2) New and/or improved high-frequency, high-temperature soft magnetic materials for the development of transformers and inductors with increased power density, energy density, electrical efficiency, and operating temperature; 3) Packaged high-temperature, high-power density, high-voltage, and low-loss SiC diodes and switches.

Superconducting thermoelectric generator

DOEpatents

Metzger, J.D.; El-Genk, M.S.

1994-01-01

Thermoelectricity is produced by applying a temperature differential to dissimilar electrically conducting or semiconducting materials, thereby producing a voltage that is proportional to the temperature difference. Thermoelectric generators use this effect to directly convert heat into electricity; however, presently-known generators have low efficiencies due to the production of high currents which in turn cause large resistive heating losses. Some thermoelectric generators operate at efficiencies between 4% and 7% in the 800{degrees} to 1200{degrees}C range. According to its major aspects and bradly stated, the present invention is an apparatus and method for producing electricity from heat. In particular, the invention is a thermoelectric generator that juxtaposes a superconducting material and a semiconducting material - so that the superconducting and the semiconducting materials touch - to convert heat energy into electrical energy without resistive losses in the temperature range below the critical temperature of the superconducting material. Preferably, an array of superconducting material is encased in one of several possible configurations within a second material having a high thermal conductivity, preferably a semiconductor, to form a thermoelectric generator.

High Temperature Materials Needs in NASA's Advanced Space Propulsion Programs

NASA Technical Reports Server (NTRS)

Eckel, Andrew J.; Glass, David E.

2005-01-01

In recent years, NASA has embarked on several new and exciting efforts in the exploration and use of space. The successful accomplishment of many planned missions and projects is dependent upon the development and deployment of previously unproven propulsion systems. Key to many of the propulsion systems is the use of emergent materials systems, particularly high temperature structural composites. A review of the general missions and benefits of utilizing high temperature materials will be presented. The design parameters and operating conditions will be presented for both specific missions/vehicles and classes of components. Key technical challenges and opportunities are identified along with suggested paths for addressing them.

Piezoelectricity above the Curie temperature? Combining flexoelectricity and functional grading to enable high-temperature electromechanical coupling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mbarki, R.; Baccam, N.; Dayal, Kaushik

Most technologically relevant ferroelectrics typically lose piezoelectricity above the Curie temperature. This limits their use to relatively low temperatures. In this Letter, exploiting a combination of flexoelectricity and simple functional grading, we propose a strategy for high-temperature electromechanical coupling in a standard thin film configuration. We use continuum modeling to quantitatively demonstrate the possibility of achieving apparent piezoelectric materials with large and temperature-stable electromechanical coupling across a wide temperature range that extends significantly above the Curie temperature. With Barium and Strontium Titanate, as example materials, a significant electromechanical coupling that is potentially temperature-stable up to 900 °C is possible.

Measurement of the high-temperature Seebeck coefficient of thin films by means of an epitaxially regrown thermometric reference material.

PubMed

Ramu, Ashok T; Mages, Phillip; Zhang, Chong; Imamura, Jeffrey T; Bowers, John E

2012-09-01

The Seebeck coefficient of a typical thermoelectric material, silicon-doped InGaAs lattice-matched to InP, is measured over a temperature range from 300 K to 550 K. By depositing and patterning a thermometric reference bar of silicon-doped InP adjacent to a bar of the material under test, temperature differences are measured directly. This is in contrast to conventional two-thermocouple techniques that subtract two large temperatures to yield a small temperature difference, a procedure prone to errors. The proposed technique retains the simple instrumentation of two-thermocouple techniques while eliminating the critical dependence of the latter on good thermal contact. The repeatability of the proposed technique is demonstrated to be ±2.6% over three temperature sweeps, while the repeatability of two-thermocouple measurements is about ±5%. The improved repeatability is significant for reliable reporting of the ZT figure of merit, which is proportional to the square of the Seebeck coefficient. The accuracy of the proposed technique depends on the accuracy with which the high-temperature Seebeck coefficient of the reference material may be computed or measured. In this work, the Seebeck coefficient of the reference material, n+ InP, is computed by rigorous solution of the Boltzmann transport equation. The accuracy and repeatability of the proposed technique can be systematically improved by scaling, and the method is easily extensible to other material systems currently being investigated for high thermoelectric energy conversion efficiency.

Three-Dimensional Printable High-Temperature and High-Rate Heaters.

PubMed

Yao, Yonggang; Fu, Kun Kelvin; Yan, Chaoyi; Dai, Jiaqi; Chen, Yanan; Wang, Yibo; Zhang, Bilun; Hitz, Emily; Hu, Liangbing

2016-05-24

High temperature heaters are ubiquitously used in materials synthesis and device processing. In this work, we developed three-dimensional (3D) printed reduced graphene oxide (RGO)-based heaters to function as high-performance thermal supply with high temperature and ultrafast heating rate. Compared with other heating sources, such as furnace, laser, and infrared radiation, the 3D printed heaters demonstrated in this work have the following distinct advantages: (1) the RGO based heater can operate at high temperature up to 3000 K because of using the high temperature-sustainable carbon material; (2) the heater temperature can be ramped up and down with extremely fast rates, up to ∼20 000 K/second; (3) heaters with different shapes can be directly printed with small sizes and onto different substrates to enable heating anywhere. The 3D printable RGO heaters can be applied to a wide range of nanomanufacturing when precise temperature control in time, placement, and the ramping rate are important.

Enhanced thermoelectric performance driven by high-temperature phase transition in the phase change material Ge 4SbTe 5

DOE PAGES

Williams, Jared B.; Lara-Curzio, Edgar; Cakmak, Ercan; ...

2015-05-15

Phase change materials are identified for their ability to rapidly alternate between amorphous and crystalline phases and have large contrast in the optical/electrical properties of the respective phases. The materials are primarily used in memory storage applications, but recently they have also been identified as potential thermoelectric materials. Many of the phase change materials researched today can be found on the pseudo-binary (GeTe) 1-x(Sb 2Te 3) x tie-line. While many compounds on this tie-line have been recognized as thermoelectric materials, here we focus on Ge 4SbTe 5, a single phase compound just off of the (GeTe) 1-x(Sb 2Te 3) xmore » tie-line, that forms in a stable rocksalt crystal structure at room temperature. We find that stoichiometric and undoped Ge 4SbTe 5 exhibits a thermal conductivity of ~1.2 W/m-K at high temperature and a large Seebeck coefficient of ~250 μV/K. The resistivity decreases dramatically at 623 K due to a structural phase transition which lends to a large enhancement in both thermoelectric power factor and thermoelectric figure of merit at 823 K. In a more general sense the research presents evidence that phase change materials can potentially provide a new route to highly efficient thermoelectric materials for power generation at high temperature.« less

Advanced Rankine and Brayton cycle power systems - Materials needs and opportunities

NASA Technical Reports Server (NTRS)

Grisaffe, S. J.; Guentert, D. C.

1974-01-01

Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long-time property data must be obtained under environments of interest to assure high component reliability.

Advanced Rankine and Brayton cycle power systems: Materials needs and opportunities

NASA Technical Reports Server (NTRS)

Grisaffe, S. J.; Guentert, D. C.

1974-01-01

Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long time property data must be obtained under environments of interest to assure high component reliability.

Electronic Structure at Oxide Interfaces

DTIC Science & Technology

2014-06-01

of materials with desired correlated electron properties such as ferromagnetism with a high Curie temperature, high transition temperature...approximation and therefore the canonical Mott picture is unable to account for the insulating behavior of these materials . We resolve this apparent...the two materials . LaTiO3 shows insulating behavior with a small excitation gap set by Ti d-d transitions and a wide energy separation between Ti d

In vitro pulp chamber temperature rise from irradiation and exotherm of flowable composites.

PubMed

Baroudi, Kusai; Silikas, Nick; Watts, David C

2009-01-01

The aim of this study was to investigate the pulpal temperature rise induced during the polymerization of flowable and non-flowable composites using light-emitting diode (LED) and halogen (quartz-tungsten-halogen) light-curing units (LCUs). Five flowable and three non-flowable composites were examined. Pulpal temperature changes were recorded over 10 min in a sample primary tooth by a thermocouple. A conventional quartz-tungsten-halogen source and two LEDs, one of which was programmable, were used for light curing the resin composites. Three repetitions per material were made for each LCU. There was a wide range of temperature rises among the materials (P < 0.05). Temperature rises ranged between 1.3 degrees C for Filtek Supreme irradiated by low-power LED and 4.5 degrees C for Grandio Flow irradiated by high-power LED. The highest temperature rises were observed with both the LED high-power and soft-start LCUs. The time to reach the exothermic peak varied significantly between the materials (P < 0.05). Pulpal temperature rise is related to both the radiant energy output from LCUs and the polymerization exotherm of resin composites. A greater potential risk for heat-induced pulp damage might be associated with high-power LED sources. Flowable composites exhibited higher temperature rises than non-flowable materials, because of higher resin contents.

High-Capacity, High-Voltage Composite Oxide Cathode Materials

NASA Technical Reports Server (NTRS)

Hagh, Nader M.

2015-01-01

This SBIR project integrates theoretical and experimental work to enable a new generation of high-capacity, high-voltage cathode materials that will lead to high-performance, robust energy storage systems. At low operating temperatures, commercially available electrode materials for lithium-ion (Li-ion) batteries do not meet energy and power requirements for NASA's planned exploration activities. NEI Corporation, in partnership with the University of California, San Diego, has developed layered composite cathode materials that increase power and energy densities at temperatures as low as 0 degC and considerably reduce the overall volume and weight of battery packs. In Phase I of the project, through innovations in the structure and morphology of composite electrode particles, the partners successfully demonstrated an energy density exceeding 1,000 Wh/kg at 4 V at room temperature. In Phase II, the team enhanced the kinetics of Li-ion transport and electronic conductivity at 0 degC. An important feature of the composite cathode is that it has at least two components that are structurally integrated. The layered material is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated and deliver a large amount of energy with stable cycling.

Corrosion-Resistant Container for Molten-Material Processing

NASA Technical Reports Server (NTRS)

Stern, Theodore G.; McNaul, Eric

2010-01-01

In a carbothermal process, gaseous methane is passed over molten regolith, which is heated past its melting point to a temperature in excess of 1,625 C. At this temperature, materials in contact with the molten regolith (or regolith simulant) corrode and lose their structural properties. As a result, fabricating a crucible to hold the molten material and providing a method of contact heating have been problematic. Alternative containment approaches use a large crucible and limit the heat zone of the material being processed, which is inefficient because of volume and mass constraints. Alternative heating approaches use non-contact heating, such as by laser or concentrated solar energy, which can be inefficient in transferring heat and thus require higher power heat sources to accomplish processing. The innovation is a combination of materials, with a substrate material having high structural strength and stiffness and high-temperature capability, and a coating material with a high corrosion resistance and high-temperature capability. The material developed is a molybdenum substrate with an iridium coating. Creating the containment crucible or heater jacket using this material combination requires only that the molybdenum, which is easily processed by conventional methods such as milling, electric discharge machining, or forming and brazing, be fabricated into an appropriate shape, and that the iridium coating be applied to any surfaces that may come in contact with the corrosive molten material. In one engineering application, the molybdenum was fashioned into a container for a heat pipe. Since only the end of the heat pipe is used to heat the regolith, the container has a narrowing end with a nipple in which the heat pipe is snugly fit, and the external area of this nipple, which contacts the regolith to transfer heat into it, is coated with iridium. At the time of this reporting, no single material has been found that can perform the functions of this combination of materials, and other combinations of materials have not proven to be survivable to the corrosiveness of this environment. High-temperature processing of materials with similar constituencies as lunar regolith is fairly common. The carbo-thermal process is commonly used to make metallurgical-grade silicon for the semiconductor and solar-cell industries.

Engineered flux-pinning centers in BSCCO TBCCO and YBCO superconductors

DOEpatents

Goretta, K.C.; Lanagan, M.T.; Miller, D.J.; Sengupta, S.; Parker, J.C.; Hu, J.; Balachandran, U.; Siegel, R.W.; Shi, D.

1999-07-27

A method of preparing a high temperature superconductor is disclosed. A method of preparing a superconductor includes providing a powdered high temperature superconductor and a nanophase material. These components are combined to form a solid compacted mass with the material disposed in the polycrystalline high temperature superconductor. This combined mixture is rapidly heated, forming a dispersion of nanophase size particles without a eutectic reaction. These nanophase particles can have a flat plate or columnar type morphology. 4 figs.

Heat treated 9 Cr-1 Mo steel material for high temperature application

DOEpatents

Jablonski, Paul D.; Alman, David; Dogan, Omer; Holcomb, Gordon; Cowen, Christopher

2012-08-21

The invention relates to a composition and heat treatment for a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650.degree. C. The novel combination of composition and heat treatment produces a heat treated material containing both large primary titanium carbides and small secondary titanium carbides. The primary titanium carbides contribute to creep strength while the secondary titanium carbides act to maintain a higher level of chromium in the finished steel for increased oxidation resistance, and strengthen the steel by impeding the movement of dislocations through the crystal structure. The heat treated material provides improved performance at comparable cost to commonly used high-temperature steels such as ASTM P91 and ASTM P92, and requires heat treatment consisting solely of austenization, rapid cooling, tempering, and final cooling, avoiding the need for any hot-working in the austenite temperature range.

Elevated Temperature Crack Growth Behavior in HSCT Structural Materials

NASA Technical Reports Server (NTRS)

Saxena, Ashok

1998-01-01

Structures in super-sonic aircraft are subjected to conditions of high temperature and cyclic and sustained loading for extended periods of time. The durability of structures fabricated from aluminum and certain titanium alloys in such demanding conditions is of primary concern to the designers and manufacturers of futuristic transport aircraft. Accordingly, the major goal of this project was to evaluate the performance and durability of high temperature aluminum and titanium alloys for use in high speed civil transport (HSCT) structures. Additional goals were to develop time-dependent fracture mechanics methodology and test methods for characterizing and predicting elevated temperature crack growth behavior in creep-brittle materials such as ones being considered for use in HSCT structures and to explore accelerated methods of simulating microstructural degradation during service and measuring degraded properties in these materials.

He implantation induced microstructure- and hardness-modification of the intermetallic γ-TiAl

NASA Astrophysics Data System (ADS)

Pouchon, Manuel A.; Chen, Jiachao; Hoffelner, Wolfgang

2009-05-01

TiAl is a well known high temperature material with good creep properties. It is investigated as a potential structural material for Generation IV high temperature gas cooled nuclear reactors. The tests are performed with the ABB-2 (Ti-rich TiAl with 2 at.% W) developed by ASEA Brown Boveri Ltd. (ABB). Thin samples are irradiated throughout with 24 MeV 4He2+ ions; the irradiated material is then investigated towards its microstructure and its hardness. The microstructure is studied by transmission electron microscopy and the hardness is investigated using a micro-hardness tester and a nano-indenter. Different effects can be identified. From room to moderate irradiation temperatures, the radiation induced hardening of the material slowly vanishes until the material completely recovers at about 943 K. Beyond this temperature, He-bubble formation seems to harden the material again, until beyond 1200 K a steep increase in hardening is detected. This effect can be correlated with bubbles being identified in the micrographs. The results are consistent and give strong indications to a microstructural development as a function of temperature.

Recent Advances in the Development of Processable High-Temperature POLYMERS1

NASA Astrophysics Data System (ADS)

Meador, Michael A.

1998-08-01

High-temperature polymers have found widespread use in aerospace and electronics applications. This review deals with recent developments in the chemistry of these materials that have led to improvements in processability and high-temperature stability.

Energy Storage of Polyarylene Ether Nitriles at High Temperature

NASA Astrophysics Data System (ADS)

Tang, Xiaohe; You, Yong; Mao, Hua; Li, Kui; Wei, Renbo; Liu, Xiaobo

2018-03-01

Polyarylene ether nitrile (PEN) was synthesized and used as film capacitors for energy storage at high temperature. Scanning electron microscopy observation indicated that the films of PEN have pinholes at nanoscales which restricted the energy storage properties of the material. The pinhole shadowing effect through which the energy storage properties of PEN were effectively improved to be 2.3 J/cm3 was observed by using the overlapped film of PEN. The high glass transition temperature (T g) of PEN was as high as 216 °C and PEN film showed stable dielectric constant, breakdown strength and energy storage density before the T g. The PEN films will be a potential candidate as high performance electronic storage materials used at high temperature.

Comparison Testings between Two High-temperature Strain Measurement Systems

NASA Technical Reports Server (NTRS)

Lei, J.-F.; Castelli, M. G.; Androjna, D.; Blue, C.; Blue, R.; Lin, R. Y.

1996-01-01

An experimental evaluation was conducted at NASA Lewis Research Center to compare and contrast the performance of a newly developed resistance strain gage, the PdCr temperature-compensated wire strain gage, to that of a conventional high-temperature extensometry. The evaluation of the two strain measurement systems was conducted through the application of various thermal and mechanical loading spectra using a high-temperature thermomechanical uniaxial testing system equipped with quartz lamp heating. The purpose of the testing was not only to compare and contrast the two strain sensors but also to investigate the applicability of the PdCr strain gage to the testing environment typically employed when characterizing the high-temperature mechanical behavior of structural materials. Strain measurement capabilities to 8OO C were investigated with a nickel base superalloy IN100 substrate material, and application to titanium matrix composite (TMC) materials was examined with the SCS-6/Ti-15-3 08 system. PdCr strain gages installed by three attachment techniques, namely, flame spraying, spot welding and rapid infrared joining were investigated.

Numerical simulation of high-temperature thermal contact resistance and its reduction mechanism.

PubMed

Liu, Donghuan; Zhang, Jing

2018-01-01

High-temperature thermal contact resistance (TCR) plays an important role in heat-pipe-cooled thermal protection structures due to the existence of contact interface between the embedded heat pipe and the heat resistive structure, and the reduction mechanism of thermal contact resistance is of special interests in the design of such structures. The present paper proposed a finite element model of the high-temperature thermal contact resistance based on the multi-point contact model with the consideration of temperature-dependent material properties, heat radiation through the cavities at the interface and the effect of thermal interface material (TIM), and the geometry parameters of the finite element model are determined by simple surface roughness test and experimental data fitting. The experimental results of high-temperature thermal contact resistance between superalloy GH600 and C/C composite material are employed to validate the present finite element model. The effect of the crucial parameters on the thermal contact resistance with and without TIM are also investigated with the proposed finite element model.

Numerical simulation of high-temperature thermal contact resistance and its reduction mechanism

PubMed Central

Zhang, Jing

2018-01-01

High-temperature thermal contact resistance (TCR) plays an important role in heat-pipe-cooled thermal protection structures due to the existence of contact interface between the embedded heat pipe and the heat resistive structure, and the reduction mechanism of thermal contact resistance is of special interests in the design of such structures. The present paper proposed a finite element model of the high-temperature thermal contact resistance based on the multi-point contact model with the consideration of temperature-dependent material properties, heat radiation through the cavities at the interface and the effect of thermal interface material (TIM), and the geometry parameters of the finite element model are determined by simple surface roughness test and experimental data fitting. The experimental results of high-temperature thermal contact resistance between superalloy GH600 and C/C composite material are employed to validate the present finite element model. The effect of the crucial parameters on the thermal contact resistance with and without TIM are also investigated with the proposed finite element model. PMID:29547651

Research for Brazing Materials of High-Temperature Thermoelectric Modules with CoSb3 Thermoelectric Materials

NASA Astrophysics Data System (ADS)

Lee, Yu Seong; Kim, Suk Jun; Kim, Byeong Geun; Lee, Soonil; Seo, Won-Seon; Kim, Il-Ho; Choi, Soon-Mok

2017-05-01

Metallic glass (MG) can be a candidate for an alternative brazing material of high-temperature thermoelectric modules, since we can expect both a lower brazing temperature and a high operating temperature for the junction from the MG brazers. Another advantage of MG powders is their outstanding oxidation resistance, namely, high-temperature durability in atmosphere. We fabricated three compositions of Al-based MGs—Al-Y-Ni, Al-Y-Ni-Co, and Al-Y-Ni-Co-La—by using the melt spinning process, and their T gs were 273°C, 264°C, and 249°C, respectively. The electrical resistivity of the Al-Y-Ni MG ribbon dropped significantly after annealing at 300°C. The electrical resistivity of crystallized Al-Y-Ni reduced down to 0.03 mΩ cm, which is an order of magnitude lower than that of the amorphous one. After the MG ribbons were pulverized to sub-100 μm, the average particle size was about 400 μm.

Mesoporous Germanium Anode Materials for Lithium-Ion Battery with Exceptional Cycling Stability in Wide Temperature Range.

PubMed

Choi, Sinho; Cho, Yoon-Gyo; Kim, Jieun; Choi, Nam-Soon; Song, Hyun-Kon; Wang, Guoxiu; Park, Soojin

2017-04-01

Porous structured materials have unique architectures and are promising for lithium-ion batteries to enhance performances. In particular, mesoporous materials have many advantages including a high surface area and large void spaces which can increase reactivity and accessibility of lithium ions. This study reports a synthesis of newly developed mesoporous germanium (Ge) particles prepared by a zincothermic reduction at a mild temperature for high performance lithium-ion batteries which can operate in a wide temperature range. The optimized Ge battery anodes with the mesoporous structure exhibit outstanding electrochemical properties in a wide temperature ranging from -20 to 60 °C. Ge anodes exhibit a stable cycling retention at various temperatures (capacity retention of 99% after 100 cycles at 25 °C, 84% after 300 cycles at 60 °C, and 50% after 50 cycles at -20 °C). Furthermore, full cells consisting of the mesoporous Ge anode and an LiFePO 4 cathode show an excellent cyclability at -20 and 25 °C. Mesoporous Ge materials synthesized by the zincothermic reduction can be potentially applied as high performance anode materials for practical lithium-ion batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrolytes for solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Fergus, Jeffrey W.

The high operating temperature of solid oxide fuel cells (SOFCs), as compared to polymer electrolyte membrane fuel cells (PEMFCs), improves tolerance to impurities in the fuel, but also creates challenges in the development of suitable materials for the various fuel cell components. In response to these challenges, intermediate temperature solid oxide fuel cells (IT-SOFCs) are being developed to reduce high-temperature material requirements, which will extend useful lifetime, improve durability and reduce cost, while maintaining good fuel flexibility. A major challenge in reducing the operating temperature of SOFCs is the development of solid electrolyte materials with sufficient conductivity to maintain acceptably low ohmic losses during operation. In this paper, solid electrolytes being developed for solid oxide fuel cells, including zirconia-, ceria- and lanthanum gallate-based materials, are reviewed and compared. The focus is on the conductivity, but other issues, such as compatibility with electrode materials, are also discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kolopus, James A.; Boatner, Lynn A.

Nanoindenters are commonly used for measuring the mechanical properties of a wide variety of materials with both industrial and scientific applications. Typically, these instruments employ an indenter made of a material of suitable hardness bonded to an appropriate shaft or holder to create an indentation on the material being tested. While a variety of materials may be employed for the indenter, diamond and boron carbide are by far the most common materials used due to their hardness and other desirable properties. However, as the increasing complexity of new materials demands a broader range of testing capabilities, conventional indenter materials exhibitmore » significant performance limitations. Among these are the inability of diamond indenters to perform in-situ measurements at temperatures above 600oC in air due to oxidation of the diamond material and subsequent degradation of the indenters mechanical properties. Similarly, boron carbide also fails at high temperature due to fracture. [1] Transition metal carbides possess a combination of hardness and mechanical properties at high temperatures that offer an attractive alternative to conventional indenter materials. Here we describe the technical aspects for the growth of single-crystal tungsten carbide (WC) for use as a high-temperature indenter material, and we examine a possible approach to brazing these crystals to a suitable mount for grinding and attachment to the indenter instrument. The use of a by-product of the recovery process is also suggested as possibly having commercial value.« less

Brief summary of the evolution of high-temperature creep-fatigue life prediction models for crack initiation

NASA Technical Reports Server (NTRS)

Halford, Gary R.

1993-01-01

The evolution of high-temperature, creep-fatigue, life-prediction methods used for cyclic crack initiation is traced from inception in the late 1940's. The methods reviewed are material models as opposed to structural life prediction models. Material life models are used by both structural durability analysts and by material scientists. The latter use micromechanistic models as guidance to improve a material's crack initiation resistance. Nearly one hundred approaches and their variations have been proposed to date. This proliferation poses a problem in deciding which method is most appropriate for a given application. Approaches were identified as being combinations of thirteen different classifications. This review is intended to aid both developers and users of high-temperature fatigue life prediction methods by providing a background from which choices can be made. The need for high-temperature, fatigue-life prediction methods followed immediately on the heels of the development of large, costly, high-technology industrial and aerospace equipment immediately following the second world war. Major advances were made in the design and manufacture of high-temperature, high-pressure boilers and steam turbines, nuclear reactors, high-temperature forming dies, high-performance poppet valves, aeronautical gas turbine engines, reusable rocket engines, etc. These advances could no longer be accomplished simply by trial and error using the 'build-em and bust-em' approach. Development lead times were too great and costs too prohibitive to retain such an approach. Analytic assessments of anticipated performance, cost, and durability were introduced to cut costs and shorten lead times. The analytic tools were quite primitive at first and out of necessity evolved in parallel with hardware development. After forty years more descriptive, more accurate, and more efficient analytic tools are being developed. These include thermal-structural finite element and boundary element analyses, advanced constitutive stress-strain-temperature-time relations, and creep-fatigue-environmental models for crack initiation and propagation. The high-temperature durability methods that have evolved for calculating high-temperature fatigue crack initiation lives of structural engineering materials are addressed. Only a few of the methods were refined to the point of being directly useable in design. Recently, two of the methods were transcribed into computer software for use with personal computers.

Brief summary of the evolution of high-temperature creep-fatigue life prediction models for crack initiation

NASA Astrophysics Data System (ADS)

Halford, Gary R.

1993-10-01

The evolution of high-temperature, creep-fatigue, life-prediction methods used for cyclic crack initiation is traced from inception in the late 1940's. The methods reviewed are material models as opposed to structural life prediction models. Material life models are used by both structural durability analysts and by material scientists. The latter use micromechanistic models as guidance to improve a material's crack initiation resistance. Nearly one hundred approaches and their variations have been proposed to date. This proliferation poses a problem in deciding which method is most appropriate for a given application. Approaches were identified as being combinations of thirteen different classifications. This review is intended to aid both developers and users of high-temperature fatigue life prediction methods by providing a background from which choices can be made. The need for high-temperature, fatigue-life prediction methods followed immediately on the heels of the development of large, costly, high-technology industrial and aerospace equipment immediately following the second world war. Major advances were made in the design and manufacture of high-temperature, high-pressure boilers and steam turbines, nuclear reactors, high-temperature forming dies, high-performance poppet valves, aeronautical gas turbine engines, reusable rocket engines, etc. These advances could no longer be accomplished simply by trial and error using the 'build-em and bust-em' approach. Development lead times were too great and costs too prohibitive to retain such an approach. Analytic assessments of anticipated performance, cost, and durability were introduced to cut costs and shorten lead times. The analytic tools were quite primitive at first and out of necessity evolved in parallel with hardware development. After forty years more descriptive, more accurate, and more efficient analytic tools are being developed. These include thermal-structural finite element and boundary element analyses, advanced constitutive stress-strain-temperature-time relations, and creep-fatigue-environmental models for crack initiation and propagation. The high-temperature durability methods that have evolved for calculating high-temperature fatigue crack initiation lives of structural engineering materials are addressed. Only a few of the methods were refined to the point of being directly useable in design.

Method and apparatus for cooling high temperature superconductors with neon-nitrogen mixtures

DOEpatents

Laverman, Royce J.; Lai, Ban-Yen

1993-01-01

Apparatus and methods for cooling high temperature superconducting materials (HTSC) to superconductive temperatures within the range of 27.degree. K. to 77.degree. K. using a mixed refrigerant consisting of liquefied neon and nitrogen containing up to about ten mole percent neon by contacting and surrounding the HTSC material with the mixed refrigerant so that free convection or forced flow convection heat transfer can be effected.

Polymer compositions based on PXE

DOEpatents

Yang, Jin; Eitouni, Hany Basam; Singh, Mohit

2015-09-15

New polymer compositions based on poly(2,6-dimethyl-1,4-phenylene oxide) and other high-softening-temperature polymers are disclosed. These materials have a microphase domain structure that has an ionically-conductive phase and a phase with good mechanical strength and a high softening temperature. In one arrangement, the structural block has a softening temperature of about 210.degree. C. These materials can be made with either homopolymers or with block copolymers.

Advanced materials research for long-haul aircraft turbine engines

NASA Technical Reports Server (NTRS)

Signorelli, R. A.; Blankenship, C. P.

1978-01-01

The status of research efforts to apply low to intermediate temperature composite materials and advanced high temperature materials to engine components is reviewed. Emerging materials technologies and their potential benefits to aircraft gas turbines were emphasized. The problems were identified, and the general state of the technology for near term use was assessed.

Low Temperature Sorbents for Removal of Sulfur Compounds from Fluid Feed Streams

DOEpatents

Siriwardane, Ranjani

2004-06-01

A sorbent material is provided comprising a material reactive with sulfur, a binder unreactive with sulfur and an inert material, wherein the sorbent absorbs the sulfur at temperatures between 30 and 200 C. Sulfur absorption capacity as high as 22 weight percent has been observed with these materials.

New Oxide Ceramic Developed for Superior High-Temperature Wear Resistance

NASA Technical Reports Server (NTRS)

Sayir, Ali; Miyoshi, Kazuhisa; Farmer, Serene C.

2003-01-01

Ceramics, for the most part, do not have inherently good tribological properties. For example friction coefficients in excess of 0.7 have been reported for silicon nitride sliding on silicon nitride or on bearing steel (ref. 1). High friction is always accompanied by considerable wear. Despite their inherently poor tribological properties, the high strength and high toughness of silicon nitride (Si3N4) ceramics has led to their successful use in tribological applications (refs. 1 to 4). The upper temperature limit for the application of Si3N4 as wear-resistant material is limited by reaction with the tribological environment (ref. 3). Silicon nitride is known to produce a thin silicon dioxide film with easy shear capability that results in low friction and low wear in a moist environment (ref. 5). At elevated temperatures, the removal of the reaction product that acts as lubricant causes the friction coefficient to increase and, consequently, the wear performance to become poor. New materials are sought that will have wear resistance superior to that of Si3N4 at elevated temperatures and in harsh environments. A new class of oxide ceramic materials has been developed with potential for excellent high-temperature wear resistance. The new material consists of a multicomponent oxide with a two-phase microstructure, in which the wear resistance of the mixed oxide is significantly higher than that of the individual constituents. This is attributed to the strong constraining effects provided by the interlocking microstructures at different length scales, to the large aspect ratio of the phases, to the strong interphase bonding, and to the residual stresses. Fretting wear tests were conducted by rubbing the new ceramic material against boron carbide (B4C). The new ceramic material produced a wear track groove on B4C, suggesting significantly higher wear resistance for the oxide ceramic. The new material did not suffer from any microstructural degradation after the wear test. The wear rate of the new ceramic material at 600 C was determined to be on the order of 10-10 mm3/N-m, which is 3 to 5 orders of magnitude lower than that for the current state-of-theart wear-resistant materials (Si3N4and B4C). The friction coefficient of the new ceramic materials is on the order of 0.4, which is significantly lower than that of silicon nitride. This new class of oxide materials has shown considerable potential for applications requiring high wear resistance at high temperatures and in harsh environments. New understanding of the wear behavior of ceramic materials is emerging as a result of the surprisingly high wear resistance of two-phase oxide ceramics. There is excellent potential for further improvements in the wear resistance of oxide ceramics through optimizing the microstructure and altering the crystallographic properties of specific oxide materials as a second phase to reduce the coefficient of friction at elevated temperatures.

Low Cost Nuclear Thermal Rocket Cermet Fuel Element Environment Testing

NASA Technical Reports Server (NTRS)

Bradley, David E.; Mireles, Omar R.; Hickman, Robert R.

2011-01-01

Deep space missions with large payloads require high specific impulse (Isp) and relatively high thrust in order to achieve mission goals in reasonable time frames. Conventional, storable propellants produce average Isp. Nuclear thermal rockets (NTR) capable of high Isp thrust have been proposed. NTR employs heat produced by fission reaction to heat and therefore accelerate hydrogen which is then forced through a rocket nozzle providing thrust. Fuel element temperatures are very high (up to 3000K) and hydrogen is highly reactive with most materials at high temperatures. Data covering the effects of high temperature hydrogen exposure on fuel elements is limited. The primary concern is the mechanical failure of fuel elements which employ high-melting-point metals, ceramics or a combination (cermet) as a structural matrix into which the nuclear fuel is distributed. It is not necessary to include fissile material in test samples intended to explore high temperature hydrogen exposure of the structural support matrices. A small-scale test bed designed to heat fuel element samples via non-contact RF heating and expose samples to hydrogen is being developed to assist in optimal material and manufacturing process selection without employing fissile material. This paper details the test bed design and results of testing conducted to date.

Compact Fuel Element Environment Test

NASA Technical Reports Server (NTRS)

Bradley, D. E.; Mireles, O. R.; Hickman, R. R.; Broadway, J. W.

2012-01-01

Deep space missions with large payloads require high specific impulse (I(sub sp)) and relatively high thrust to achieve mission goals in reasonable time frames. Conventional, storable propellants produce average I(sub sp). Nuclear thermal rockets (NTRs) capable of high I(sub sp) thrust have been proposed. NTR employs heat produced by fission reaction to heat and therefore accelerate hydrogen, which is then forced through a rocket nozzle providing thrust. Fuel element temperatures are very high (up to 3,000 K) and hydrogen is highly reactive with most materials at high temperatures. Data covering the effects of high-temperature hydrogen exposure on fuel elements are limited. The primary concern is the mechanical failure of fuel elements that employ high melting point metals, ceramics, or a combination (cermet) as a structural matrix into which the nuclear fuel is distributed. It is not necessary to include fissile material in test samples intended to explore high-temperature hydrogen exposure of the structural support matrices. A small-scale test bed designed to heat fuel element samples via noncontact radio frequency heating and expose samples to hydrogen for typical mission durations has been developed to assist in optimal material and manufacturing process selection without employing fissile material. This Technical Memorandum details the test bed design and results of testing conducted to date.

Ultrasonic High-Temperature Sensors: Past Experiments and Prospects for Future Use

NASA Astrophysics Data System (ADS)

Laurie, M.; Magallon, D.; Rempe, J.; Wilkins, C.; Pierre, J.; Marquié, C.; Eymery, S.; Morice, R.

2010-09-01

Ultrasonic thermometry sensors (UTS) have been intensively studied in the past to measure temperatures from 2080 K to 3380 K. This sensor, which uses the temperature dependence of the acoustic velocity in materials, was developed for experiments in extreme environments. Its major advantages, which are (a) capability of measuring a temperature profile from multiple sensors on a single probe and (b) measurement near the sensor material melting point, can be of great interest when dealing with on-line monitoring of high-temperature safety tests. Ultrasonic techniques were successfully applied in several severe accident related experiments. With new developments of alternative materials, this instrument may be used in a wide range of experimental areas where robustness and compactness are required. Long-term irradiation experiments of nuclear fuel to extremely high burn-ups could benefit from this previous experience. After an overview of UTS technology, this article summarizes experimental work performed to improve the reliability of these sensors. The various designs, advantages, and drawbacks are outlined and future prospects for long-term high-temperature irradiation experiments are discussed.

Low Cost Nuclear Thermal Rocket Cermet Fuel Element Environment Testing

NASA Technical Reports Server (NTRS)

Bradley, D. E.; Mireles, O. R.; Hickman, R. R.

2011-01-01

Deep space missions with large payloads require high specific impulse and relatively high thrust to achieve mission goals in reasonable time frames.1,2 Conventional storable propellants produce average specific impulse. Nuclear thermal rockets capable of producing high specific impulse are proposed. Nuclear thermal rockets employ heat produced by fission reaction to heat and therefore accelerate hydrogen, which is then forced through a rocket nozzle providing thrust. Fuel element temperatures are very high (up to 3000 K), and hydrogen is highly reactive with most materials at high temperatures. Data covering the effects of high-temperature hydrogen exposure on fuel elements are limited.3 The primary concern is the mechanical failure of fuel elements that employ high-melting-point metals, ceramics, or a combination (cermet) as a structural matrix into which the nuclear fuel is distributed. The purpose of the testing is to obtain data to assess the properties of the non-nuclear support materials, as-fabricated, and determine their ability to survive and maintain thermal performance in a prototypical NTR reactor environment of exposure to hydrogen at very high temperatures. The fission process of the planned fissile material and the resulting heating performance is well known and does not therefore require that active fissile material be integrated in this testing. A small-scale test bed designed to heat fuel element samples via non-contact radio frequency heating and expose samples to hydrogen is being developed to assist in optimal material and manufacturing process selection without employing fissile material. This paper details the test bed design and results of testing conducted to date.

Corrosion Issues for Ceramics in Gas Turbines

NASA Technical Reports Server (NTRS)

Jacobson, Nathan S.; Fox, Dennis S.; Smialek, James L.; Opila, Elizabeth J.; Tortorelli, Peter F.; More, Karren L.; Nickel, Klaus G.; Hirata, Takehiko; Yoshida, Makoto; Yuri, Isao

2000-01-01

The requirements for hot-gas-path materials in gas turbine engines are demanding. These materials must maintain high strength and creep resistance in a particularly aggressive environment. A typical gas turbine environment involves high temperatures, rapid gas flow rates, high pressures, and a complex mixture of aggressive gases. Figure 26.1 illustrates the requirements for components of an aircraft engine and critical issues [1]. Currently, heat engines are constructed of metal alloys, which meet these requirements within strict temperature limits. In order to extend these temperature limits, ceramic materials have been considered as potential engine materials, due to their high melting points and stability at high temperatures. These materials include oxides, carbides, borides, and nitrides. Interest in using these materials in engines appears to have begun in the 1940s with BeO-based porcelains [2]. During the 1950s, the efforts shifted to cermets. These were carbide-based materials intended to exploit the best properties of metals and ceramics. During the 1960s and 1970s, the silicon-based ceramics silicon carbide (SiC) and silicon nitride (Si3N4) were extensively developed. Although the desirable high-temperature properties of SiC and Si3N4 had long been known, consolidation of powders into component-sized bodies required the development of a series of specialized processing routes [3]. For SiC, the major consolidation routes are reaction bonding, hot-pressing, and sintering. The use of boron and carbon as additives which enable sintering was a particularly noteworthy advance [4]. For Si3N4 the major consolidation routes are reaction bonding and hot pressing [5]. Reaction-bonding involves nitridation of silicon powder. Hot pressing involves addition of various refractory oxides, such as magnesia (MgO), alumina (Al2O3), and yttria (y2O3). Variations on these processes include a number of routes including Hot Isostatic Pressing (HIP), gas-pressure sintering, sinter-HIPing, and Encapsulation-HIPing. It is important to note that each process involves the addition of secondary elements, which later were shown to dramatically influence oxidation and corrosion behavior. As dense bodies of silicon-based ceramics became more readily available, their desirable high temperature properties were confirmed. These materials retained strength to very high temperatures (i.e. 1300-1400 C). Further, they were lightweight and made from abundant materials. SiC and Si3N4 therefore emerged as leading ceramic candidates for components in heat engines, designed to operate at higher temperatures for better performance and fuel efficiency. The first US programs for ceramics in heat engines have been reviewed [6]. Selected programs on ceramic engine parts are summarized here in regard to their contributions to understanding the corrosion behavior of a heat engine environment.

Materials insights into low-temperature performances of lithium-ion batteries

NASA Astrophysics Data System (ADS)

Zhu, Gaolong; Wen, Kechun; Lv, Weiqiang; Zhou, Xingzhi; Liang, Yachun; Yang, Fei; Chen, Zhilin; Zou, Minda; Li, Jinchao; Zhang, Yuqian; He, Weidong

2015-12-01

Lithium-ion batteries (LIBs) have been employed in many fields including cell phones, laptop computers, electric vehicles (EVs) and stationary energy storage wells due to their high energy density and pronounced recharge ability. However, energy and power capabilities of LIBs decrease sharply at low operation temperatures. In particular, the charge process becomes extremely sluggish at temperatures below -20 °C, which severely limits the applications of LIBs in some cold areas during winter. Extensive research has shown that the electrolyte/electrode composition and microstructure are of fundamental importance to low-temperature performances of LIBs. In this report, we review the recent findings in the role of electrolytes, anodes, and cathodes in the low temperature performances of LIBs. Our overview aims to understand comprehensively the fundamental origin of low-temperature performances of LIBs from a materials perspective and facilitates the development of high-performance lithium-ion battery materials that are operational at a large range of working temperatures.

Shock temperature measurement of transparent materials under shock compression

NASA Astrophysics Data System (ADS)

Hu, Jinbiao

1999-06-01

Under shock compression, some materials have very small absorptance. So it's emissivity is very small too. For this kinds of materials, although they stand in high temperature state under shock compression, the temperature can not be detected easily by using optical radiation technique because of the low emissivity. In this paper, an optical radiation temperature measurement technique of measuring temperature of very low emissive material under shock compression was proposed. For making sure this technique, temperature of crystal NaCl at shock pressure 41 GPa was measured. The result agrees with the results of Kormer et al and Ahrens et al very well. This shows that this technique is reliable and can be used to measuring low emissive shock temperature.

Basalt fiber insulating material with a mineral binding agent for industrial use

NASA Astrophysics Data System (ADS)

Drozdyuk, T.; Aizenshtadt, A.; Tutygin, A.; Frolova, M.

2016-04-01

The paper considers a possibility of using mining industry waste as a binding agent for heat insulating material on the basis of basalt fiber. The main objective of the research is to produce a heat-insulating material to be applied in machine building in high-temperature environments. After synthetic binder having been replaced by a mineral one, an environmentally sound thermal insulating material having desirable heat-protecting ability and not failing when exposed to high temperatures was obtained.

Plasma technologies application for building materials surface modification

NASA Astrophysics Data System (ADS)

Volokitin, G. G.; Skripnikova, N. K.; Volokitin, O. G.; Shehovtzov, V. V.; Luchkin, A. G.; Kashapov, N. F.

2016-01-01

Low temperature arc plasma was used to process building surface materials, such as silicate brick, sand lime brick, concrete and wood. It was shown that building surface materials modification with low temperature plasma positively affects frost resistance, water permeability and chemical resistance with high adhesion strength. Short time plasma processing is rather economical than traditional processing thermic methods. Plasma processing makes wood surface uniquely waterproof and gives high operational properties, dimensional and geometrical stability. It also increases compression resistance and decreases inner tensions level in material.

Compliant Interfacial Layers in Thermoelectric Devices

NASA Technical Reports Server (NTRS)

Firdosy, Samad A. (Inventor); Li, Billy Chun-Yip (Inventor); Ravi, Vilupanur A. (Inventor); Fleurial, Jean-Pierre (Inventor); Caillat, Thierry (Inventor); Anjunyan, Harut (Inventor)

2017-01-01

A thermoelectric power generation device is disclosed using one or more mechanically compliant and thermally and electrically conductive layers at the thermoelectric material interfaces to accommodate high temperature differentials and stresses induced thereby. The compliant material may be metal foam or metal graphite composite (e.g. using nickel) and is particularly beneficial in high temperature thermoelectric generators employing Zintl thermoelectric materials. The compliant material may be disposed between the thermoelectric segments of the device or between a thermoelectric segment and the hot or cold side interconnect of the device.

High voltage insulation of bushing for HTS power equipment

NASA Astrophysics Data System (ADS)

Kim, Woo-Jin; Choi, Jae-Hyeong; Kim, Sang-Hyun

2012-12-01

For the operation of high temperature superconducting (HTS) power equipments, it is necessary to develop insulating materials and high voltage (HV) insulation technology at cryogenic temperature of bushing. Liquid nitrogen (LN2) is an attractive dielectric liquid. Also, the polymer insulating materials are expected to be used as solid materials such as glass fiber reinforced plastic (GFRP), polytetra-fluoroethylene (PTFE, Teflon), Silicon (Si) rubber, aromatic polyamide (Nomex), EPDM/Silicon alloy compound (EPDM/Si). In this paper, the surface flashover characteristics of various insulating materials in LN2 are studied. These results are studied at both AC and impulse voltage under a non-uniform field. The use of GFRP and Teflon as insulation body for HTS bushing should be much desirable. Especially, GFRP is excellent material not only surface flashover characteristics but also mechanical characteristics at cryogenic temperature. The surface flashover is most serious problem for the shed design in LN2 and operation of superconducting equipments.

Influence of hole transport material/metal contact interface on perovskite solar cells

NASA Astrophysics Data System (ADS)

Lei, Lei; Zhang, Shude; Yang, Songwang; Li, Xiaomin; Yu, Yu; Wei, Qingzhu; Ni, Zhichun; Li, Ming

2018-06-01

Interfaces have a significant impact on the performance of perovskite solar cells. This work investigated the influence of hole transport material/metal contact interface on photovoltaic behaviours of perovskite solar devices. Different hole material/metal contact interfaces were obtained by depositing the metal under different conditions. High incident kinetic energy metal particles were proved to penetrate and embed into the hole transport material. These isolated metal particles in hole transport materials capture holes and increase the apparent carrier transport resistance of the hole transport layer. Sample temperature was found to be of great significance in metal deposition. Since metal vapour has a high temperature, the deposition process accumulated a large amount of heat. The heat evaporated the additives in the hole transport layer and decreased the hole conductivity. On the other hand, high temperature may cause iodization of the metal contact.

Influence of hole transport material/metal contact interface on perovskite solar cells.

PubMed

Lei, Lei; Zhang, Shude; Yang, Songwang; Li, Xiaomin; Yu, Yu; Wei, Qingzhu; Ni, Zhichun; Li, Ming

2018-06-22

Interfaces have a significant impact on the performance of perovskite solar cells. This work investigated the influence of hole transport material/metal contact interface on photovoltaic behaviours of perovskite solar devices. Different hole material/metal contact interfaces were obtained by depositing the metal under different conditions. High incident kinetic energy metal particles were proved to penetrate and embed into the hole transport material. These isolated metal particles in hole transport materials capture holes and increase the apparent carrier transport resistance of the hole transport layer. Sample temperature was found to be of great significance in metal deposition. Since metal vapour has a high temperature, the deposition process accumulated a large amount of heat. The heat evaporated the additives in the hole transport layer and decreased the hole conductivity. On the other hand, high temperature may cause iodization of the metal contact.

Prototype rigid polyimide components. [application of Apollo technology to commercial nonflammable materials

NASA Technical Reports Server (NTRS)

Wykes, D. H.

1975-01-01

The activity is reported which was conducted for utilizing spin-off Apollo base technology to fabricate a variety of commercial and aerospace related parts that are nonflammable and resistant to high-temperature degradation. Manufacturing techniques and the tooling used to fabricate each of the polyimide/glass structures is discussed. A brief history, tracing the development of high-temperature polyimide resins, is presented along with a discussion of the properties of DuPont's PI 2501/glass material (later redesignated PI 4701/glass). Mechanical and flammability properties of DuPont's PI 2501/glass laminates are compared with epoxy, phenolic, and silicone high-temperature resin/glass material systems. Offgassing characteristics are also presented. A discussion is included of the current developments in polyimide materials technology and the potential civilian and government applications of polyimide materials to reduce fire hazards and increase the survivability of men and equipment.

High-resistive layers obtained through periodic growth and in situ annealing of InGaN by metalorganic chemical vapor deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Shuo; Ma, Ping, E-mail: maping@semi.ac.cn; Liu, Boting

2016-06-15

High-resistive layers were obtained by periodic growth and in situ annealing of InGaN. The effect of the annealing temperature of InGaN on the indium content and the material sheet resistive was investigated. The indium content decreased as the increase of in situ annealing temperature. Additionally, the material sheet resistance increased with the increase of the in situ annealing temperature for the annealed samples and reached 2 × 10{sup 10}Ω/sq in the light and 2 × 10{sup 11}Ω/sq in the dark when the in situ annealing temperature reached 970{sup ∘}C. The acquirement of high-resistive layers is attributed to the generation ofmore » indium vacancy-related defects. Introducing indium vacancy-related defects to compensate background carriers can be an effective method to grow high-resistance material.« less

Evaluation of Additive Manufacturing for Stainless Steel Components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peter, William H.; Lou, Xiaoyuan; List, III, Frederick Alyious

This collaboration between Oak Ridge National Laboratory and General Electric Company aimed to evaluate the mechanical properties, microstructure, and porosity of the additively manufactured 316L stainless steel by ORNL’s Renishaw AM250 machine for nuclear application. The program also evaluated the stress corrosion cracking and corrosion fatigue crack growth rate of the same material in high temperature water environments. Results show the properties of this material to be similar to the properties of 316L stainless steel fabricated additively with equipment from other manufacturers with slightly higher porosity. The stress corrosion crack growth rate is similar to that for wrought 316L stainlessmore » steel for an oxygenated high temperature water environment and slightly higher for a hydrogenated high temperature water environment. Optimized heat treatment of this material is expected to improve performance in high temperature water environments.« less

Update on High-Temperature Coils for Electromagnets

NASA Technical Reports Server (NTRS)

Kascak, Albert F.; Montague, Gerald T.; Palazzolo, Alan; Preuss, Jason; Carter, Bart; Tucker, Randall; Hunt, Andrew

2005-01-01

A report revisits the subject matter of "High-Temperature Coils for Electromagnets" (LEW-17164), NASA Tech Briefs, Vol. 26, No. 8, (August 2002) page 38. To recapitulate: Wires have been developed for use in electromagnets that operate at high temperatures. The starting material for a wire of this type can be either a nickel-clad, ceramic-insulated copper wire or a bare silver wire. The wire is covered by electrical-insulation material that is intended to withstand operating temperatures in the range from 800 to 1,300 F (.430 to .700 C): The starting wire is either primarily wrapped with S-glass as an insulating material or else covered with another insulating material wrapped in S-glass prior to the winding process. A ceramic binding agent is applied as a slurry during the winding process to provide further insulating capability. The turns are pre-bent during winding to prevent damage to the insulation. The coil is then heated to convert the binder into ceramic. The instant report mostly reiterates the prior information and presents some additional information on the application of the ceramic binding agent and the incorporation of high-temperature wire into the windings.

High-Temperature Proton-Conducting Ceramics Developed

NASA Technical Reports Server (NTRS)

Sayir, Ali; Dynys, Frederick W.; Berger, M. H.

2005-01-01

High-temperature protonic conductors (HTPC) are needed for hydrogen separation, hydrogen sensors, fuel cells, and hydrogen production from fossil fuels. The HTPC materials for hydrogen separation at high temperatures are foreseen to be metal oxides with the perovskite structure A(sup 2+)B(sup 4+)C(sup 2-, sub 3) and with the trivalent cation (M(sup 3+)) substitution at the B(sup 4+)-site to introduce oxygen vacancies. The high affinity for hydrogen ions (H(sup +)) is advantageous for protonic transport, but it increases the reactivity toward water (H2O) and carbon dioxide (CO2), which can lead to premature membrane failure. In addition, there are considerable technological challenges related to the processing of HTPC materials. The high melting point and multi-cation chemistry of HTPC materials creates difficulties in in achieving high-density, single-phase membranes by solid-state sintering. The presence of secondary phases and grain-boundary interfaces are detrimental to the protonic conduction and environmental stability of polycrystalline HTPC materials.

Probabilistic Material Strength Degradation Model for Inconel 718 Components Subjected to High Temperature, High-Cycle and Low-Cycle Mechanical Fatigue, Creep and Thermal Fatigue Effects

NASA Technical Reports Server (NTRS)

Bast, Callie C.; Boyce, Lola

1995-01-01

The development of methodology for a probabilistic material strength degradation is described. The probabilistic model, in the form of a postulated randomized multifactor equation, provides for quantification of uncertainty in the lifetime material strength of aerospace propulsion system components subjected to a number of diverse random effects. This model is embodied in the computer program entitled PROMISS, which can include up to eighteen different effects. Presently, the model includes five effects that typically reduce lifetime strength: high temperature, high-cycle mechanical fatigue, low-cycle mechanical fatigue, creep and thermal fatigue. Results, in the form of cumulative distribution functions, illustrated the sensitivity of lifetime strength to any current value of an effect. In addition, verification studies comparing predictions of high-cycle mechanical fatigue and high temperature effects with experiments are presented. Results from this limited verification study strongly supported that material degradation can be represented by randomized multifactor interaction models.

Influence of the composite material thermal expansion on embedded highly birefringent polymer microstructured optical fibers

NASA Astrophysics Data System (ADS)

SzelÄ g, M.; Lesiak, P.; Kuczkowski, M.; Domański, A. W.; Woliński, T. R.

2013-05-01

Results of our research on embedded highly birefringent polymer microstructured fibers are presented. A composite material sample with fibers embedded between two layers of a multi-layer composite structure is fabricated and characterized. Temperature sensitivities of the polymer fibers are measured in a free space and compared with the fibers embedded in the composite material. It appeared that highly birefringent polymer microstructured fibers exhibit a strong increase in temperature sensitivity when embedded in the composite material, which is due to the stress-induced changes in birefringence created by thermally-induced strain.

High temperature electrical conductivity of rigid polyurethane foam

NASA Astrophysics Data System (ADS)

Johnson, R. T., Jr.

1984-03-01

The temperature dependence of the electrical conductivity of three rigid polyurethane foams prepared using different formulations was measured to approx. 320 C. The materials exhibit similar conductivity characteristics, showing a pronounced increase in conductivity with increasing temperature. The insulating characteristics to approx. 200 C are better than that for phenolic materials (glass fabric reinforced), and are similar to those for silicone materials (glass microsphere reinforced). At higher temperatures (500 to 600 C), the phenolics and silicones are better insulators.

Intermetallic and ceramic matrix composites for 815 to 1370 C (1500 to 2500 F) gas turbine engine applications

NASA Technical Reports Server (NTRS)

Stephens, Joseph R.

1989-01-01

Light weight and potential high temperature capability of intermetallic compounds, such as the aluminides, and structural ceramics, such as the carbides and nitrides, make these materials attractive for gas turbine engine applications. In terms of specific fuel consumption and specific thrust, revolutionary improvements over current technology are being sought by realizing the potential of these materials through their use as matrices combined with high strength, high temperature fibers. The U.S. along with other countries throughout the world have major research and development programs underway to characterize these composites materials; improve their reliability; identify and develop new processing techniques, new matrix compositions, and new fiber compositions; and to predict their life and failure mechanisms under engine operating conditions. The status is summarized of NASA's Advanced High Temperature Engine Materials Technology Program (HITEMP) and the potential benefits are described to be gained in 21st century transport aircraft by utilizing intermetallic and ceramic matrix composite materials.

From microporous regular frameworks to mesoporous materials with ultrahigh surface area: dynamic reorganization of porous polymer networks.

PubMed

Kuhn, Pierre; Forget, Aurélien; Su, Dangsheng; Thomas, Arne; Antonietti, Markus

2008-10-08

High surface area organic materials featuring both micro- and mesopores were synthesized under ionothermal conditions via the formation of polyaryltriazine networks. While the polytrimerization of nitriles in zinc chloride at 400 degrees C produces microporous polymers, higher reaction temperatures induce the formation of additional spherical mesopores with a narrow dispersity. The nitrogen-rich carbonaceous polymer materials thus obtained present surface areas and porosities up to 3300 m(2) g(-1) and 2.4 cm(3) g(-1), respectively. The key point of this synthesis relies on the occurrence of several high temperature polymerization reactions, where irreversible carbonization reactions coupled with the reversible trimerization of nitriles allow the reorganization of the dynamic triazine network. The ZnCl2 molten salt fulfills the requirement of a high temperature solvent, but is also required as catalyst. Thus, this dynamic polymerization system provides not only highly micro- and mesoporous materials, but also allows controlling the pore structure in amorphous organic materials.

Synthesis of thin films and materials utilizing a gaseous catalyst

DOEpatents

Morse, Daniel E; Schwenzer, Birgit; Gomm, John R; Roth, Kristian M; Heiken, Brandon; Brutchey, Richard

2013-10-29

A method for the fabrication of nanostructured semiconducting, photoconductive, photovoltaic, optoelectronic and electrical battery thin films and materials at low temperature, with no molecular template and no organic contaminants. High-quality metal oxide semiconductor, photovoltaic and optoelectronic materials can be fabricated with nanometer-scale dimensions and high dopant densities through the use of low-temperature biologically inspired synthesis routes, without the use of any biological or biochemical templates.

Mechanical Properties of High Manganese Austenitic Stainless Steel JK2LB for ITER Central Solenoid Jacket Material

NASA Astrophysics Data System (ADS)

Saito, Toru; Kawano, Katsumi; Yamazaki, Toru; Ozeki, Hidemasa; Isono, Takaaki; Hamada, Kazuya; Devred, Arnaud; Vostner, Alexander

A suite of advanced austenitic stainless steels are used for the ITER TF, CS and PF coil systems.These materials will be exposed to cyclic-stress at cryogenic temperature. Therefore, high manganese austenitic stainless steel JK2LB, which has high tensile strength, high ductility and high resistance to fatigue at 4 K has been chosen for the CS conductor. The cryogenic temperature mechanical property data of this material are very important for the ITER magnet design. This study is focused on mechanical characteristics of JK2LB and its weld joint.

Effect of annealing high-dose heavy-ion irradiated high-temperature superconductor wires

NASA Astrophysics Data System (ADS)

Strickland, N. M.; Wimbush, S. C.; Kluth, P.; Mota-Santiago, P.; Ridgway, M. C.; Kennedy, J. V.; Long, N. J.

2017-10-01

Heavy-ion irradiation of high-temperature superconducting thin films has long been known to generate damage tracks of amorphized material that are of close-to-ideal dimension to effectively contribute to pinning of magnetic flux lines and thereby enhance the in-field critical current. At the same time, though, the presence of these tracks reduces the superconducting volume fraction available to transport current while the irradiation process itself generates oxygen depletion and disorder in the remaining superconducting material. We have irradiated commercially available superconducting coated conductors consisting of a thick film of (Y,Dy)Ba2Cu3O7 deposited on a buffered metal tape substrate in a continuous reel-to-reel process. Irradiation was by 185 MeV 197Au ions. A high fluence of 3 × 1011 ions/cm2 was chosen to emphasize the detrimental effects. The critical current was reduced following this irradiation, but annealing at relatively low temperatures of 200 °C and 400 °C substantially restore the critical current of the irradiated material. At high fields and high temperatures there is a net benefit of critical current compared to the untreated material.

Acousto-optic Imaging System for In-situ Measurement of the High Temperature Distribution in Micron-size Specimens

NASA Astrophysics Data System (ADS)

Machikhin, Alexander S.; Zinin, Pavel V.; Shurygin, Alexander V.

We developed a unique acousto-optic imaging system for in-situ measurement of high temperature distribution on micron-size specimens. The system was designed to measure temperature distribution inside minerals and functional material phases subjected to high pressure and high temperatures in a diamond anvil cell (DAC) heated by a high powered laser.

An investigation into the impact of cryogenic environment on mechanical stresses in FRP composites

NASA Astrophysics Data System (ADS)

Fifo, O.; Basu, B.

2015-07-01

Fibre reinforced polymer (FRP) composites are fast becoming a highly utilised engineering material for high performance applications due to their light weight and high strength. Carbon fibre and other high strength fibres are commonly used in design of aerospace structures, wind turbine blades, etc. and potentially for propellant tanks of launch vehicles. For the aforementioned fields of application, stability of the material is essential over a wide range of temperature particularly for structures in hostile environments. Many studies have been conducted, experimentally, over the last decade to investigate the mechanical behaviour of FRP materials at varying subzero temperature. Likewise, tests on aging and cycling effect (room to low temperature) on the mechanical response of FRP have been reported. However, a relatively lesser focused area has been the mechanical behaviour of FRP composites under cryogenic environment. This article reports a finite element method of investigating the changes in the mechanical characteristics of an FRP material when temperature based analysis falls below zero. The simulated tests are carried out using a finite element package with close material properties used in the cited literatures. Tensile test was conducted and the results indicate that the mechanical responses agree with those reported in the literature sited.

Structural characterization of high temperature composites

NASA Technical Reports Server (NTRS)

Mandell, J. F.; Grande, D. H.

1991-01-01

Glass, ceramic, and carbon matrix composite materials have emerged in recent years with potential properties and temperature resistance which make them attractive for high temperature applications such as gas turbine engines. At the outset of this study, only flexural tests were available to evaluate brittle matrix composites at temperatures in the 600 to 1000 C range. The results are described of an ongoing effort to develop appropriate tensile, compression, and shear test methods for high temperature use. A tensile test for unidirectional composites was developed and used to evaluate the properties and behavior of ceramic fiber reinforced glass and glass-ceramic matrix composites in air at temperatures up to 1000 C. The results indicate generally efficient fiber reinforcement and tolerance to matrix cracking similar to polymer matrix composites. Limiting properties in these materials may be an inherently very low transverse strain to failure, and high temperature embrittlement due to fiber/matrix interface oxidation.

Origin of colossal dielectric response in (In + Nb) co-doped TiO2 rutile ceramics: a potential electrothermal material.

PubMed

Ke, Shanming; Li, Tao; Ye, Mao; Lin, Peng; Yuan, Wenxiang; Zeng, Xierong; Chen, Lang; Huang, Haitao

2017-08-31

(In + Nb) co-doped TiO 2 (TINO) rutile is an emerging material with a colossal dielectric permittivity (CP) and a low dielectric loss over wide temperature and frequency ranges. The electrical inhomogeneous nature of TINO ceramics is demonstrated by direct local current probing with high-resolution conductive atomic force microscopy (cAFM). The CP response in TINO is found to originate from the electron-pinned defect dipole induced conductive cluster effect and the electrode effect. Two types of dielectric relaxations are simultaneously observed due to these two effects. With the given synthesis condition, we found TINO shows a highly leaky feature that impairs its application as a dielectric material. However, the fast-temperature-rising phenomenon found in this work may open a new door for TINO to be applied as a potential electrothermal material with high efficiency, oxidation-proof, high temperature stability, and energy saving.

Reactor and method for hydrocracking carbonaceous material

DOEpatents

Duncan, Dennis A.; Beeson, Justin L.; Oberle, R. Donald; Dirksen, Henry A.

1980-01-01

Solid, carbonaceous material is cracked in the presence of hydrogen or other reducing gas to provide aliphatic and aromatic hydrocarbons of lower molecular weight for gaseous and liquid fuels. The carbonaceous material, such as coal, is entrained as finely divided particles in a flow of reducing gas and preheated to near the decomposition temperature of the high molecular weight polymers. Within the reactor, small quantities of oxygen containing gas are injected at a plurality of discrete points to burn corresponding amounts of the hydrogen or other fuel and elevate the mixture to high temperatures sufficient to decompose the high molecular weight, carbonaceous solids. Turbulent mixing at each injection point rapidly quenches the material to a more moderate bulk temperature. Additional quenching after the final injection point can be performed by direct contact with quench gas or oil. The reactions are carried out in the presence of a hydrogen-containing reducing gas at moderate to high pressure which stabilizes the products.

Evaluation of an innovative high temperature ceramic wafer seal for hypersonic engine applications. Ph.D. Thesis, 1991

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.

1992-01-01

A critical mechanical system in advanced hypersonic engines is the panel-edge seal system that seals gaps between the articulating engine panels and the adjacent engine splitter walls. Significant advancements in seal technology are required to meet the extreme demands placed on the seals, including the simultaneous requirements of low leakage, conformable, high temperature, high pressure, sliding operation. In this investigation, the design, development, analytical and experimental evaluation of a new ceramic wafer seal that shows promise of meeting these demands will be addressed. A high temperature seal test fixture was designed and fabricated to measure static seal leakage performance under engine simulated conditions. Ceramic wafer seal leakage rates are presented for engine-simulated air pressure differentials (up to 100 psi), and temperature (up to 1350 F), sealing both flat and distorted wall conditions, where distortions can be as large as 0.15 inches in only an 18 inch span. Seal leakage rates are low, meeting an industry-established tentative leakage limit for all combinations of temperature, pressure and wall conditions considered. A seal leakage model developed from externally-pressurized gas film bearing theory is also presented. Predicted leakage rates agree favorably with the measured data for nearly all conditions of temperature and pressure. Discrepancies noted at high engine pressure and temperature are attributed to thermally-induced, non-uniform changes in the size and shape of the leakage gap condition. The challenging thermal environment the seal must operate in places considerable demands on the seal concept and material selection. Of the many high temperature materials considered in the design, ceramics were the only materials that met the many challenging seal material design requirements. Of the aluminum oxide, silicon carbide, and silicon nitride ceramics considered in the material ranking scheme developed herein, the silicon nitride class of ceramics ranked the highest because of their high temperature strength; resistance to the intense heating rates; resistance to hydrogen damage; and good structural properties. Baseline seal feasibility has been established through the research conducted in this investigation. Recommendations for future work are also discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Lu

The objective of this research is to investigate the high-field magnetic properties of high temperature superconductors, materials that conduct electricity without loss. A technique known as high-resolution torque magnetometry that was developed to directly measure the magnetization of high temperature superconductors. This technique was implemented using the 65 Tesla pulsed magnetic field facility that is part of the National High Magnetic Field Laboratory at Los Alamos National Laboratory. This research addressed unanswered questions about the interplay between magnetism and superconductivity, determine the electronic structure of high temperature superconductors, and shed light on the mechanism of high temperature superconductivity and onmore » potential applications of these materials in areas such as energy generation and power transmission. Further applications of the technology resolve the novel physical phenomena such as correlated topological insulators, and spin liquid state in quantum magnets.« less

Some composite bearing and seal materials for gas turbine applications: A review

NASA Technical Reports Server (NTRS)

Sliney, Harold E.

1989-01-01

A review is made of the selection and tribological testing of materials for high-temperature bearings and seals. The goal is to achieve good tribological properties over a wide range of temperatures because bearings and seals must be functional from low temperature start-up conditions on up to the maximum temperatures encountered during engine operation. Plasma sprayed composite coatings with favorable tribological properties from 25 to 900 C are discussed. The performance of these coatings in simple tribological bench tests is described. Examples are also given of their performance in high-speed sliding contact seals and as Stirling cylinder liner materials, and as back up lubricants for compliant foil gas bearings.

Trends in high temperature gas turbine materials

NASA Technical Reports Server (NTRS)

Grisaffe, S. J.; Dreshfield, R. L.

1981-01-01

High performance - high technology materials are among the technologies that are required to allow the fruition of such improvements. Materials trends in hot section components are reviewed, and materials for future use are identified. For combustors, airfoils, and disks, a common trend of using multiple material construction to permit advances in technology is identified.

Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

NASA Technical Reports Server (NTRS)

Cox, Sarah B.; Lui, Donovan; Gou, Jihua

2014-01-01

The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200C, beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

NASA Technical Reports Server (NTRS)

Cox, Sarah B.; Lui, Donovan; Wang, Xin; Gou, Jihua

2014-01-01

The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000 deg C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200 deg C, Beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

Numerical analysis of phase change materials for thermal control of power battery of high power dissipations

NASA Astrophysics Data System (ADS)

Xia, X.; Zhang, H. Y.; Deng, Y. C.

2016-08-01

Solid-fluid phase change materials have been of increasing interest in various applications due to their high latent heat with minimum volume change. In this work, numerical analysis of phase change materials is carried out for the purpose of thermal control of the cylindrical power battery cells for applications in electric vehicles. Uniform heat density is applied at the battery cell, which is surrounded by phase change material (PCM) of paraffin wax type and contained in a metal housing. A two-dimensional geometry model is considered due to the model symmetry. The effects of power densities, heat transfer coefficients and onset melting temperatures are examined for the battery temperature evolution. Temperature plateaus can be observed from the present numerical analysis for the pure PCM cases, with the temperature level depending on the power densities, heat transfer coefficients, and melting temperatures. In addition, the copper foam of high thermal conductivity is inserted into the copper foam to enhance the heat transfer. In the modeling, the local thermal non-equilibrium between the metal foam and the PCM is taken into account and the temperatures for the metal foam and PCM are obtained respectively.

Alloy steel nuts for bolting for high-pressure and high-temperature service (ASME SA-194 with additional requirements)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This standard covers alloy steel nuts for bolting for high-pressure and high-temperature service in nuclear and associated applications. This standard does not cover bar or other starting materials. The only implied special considerations for starting materials are that they be capable of passing the required tests when processed into finished products in accordance with this standard.

High temperature materials characterization

NASA Technical Reports Server (NTRS)

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.

Preparation and composition of superconducting copper oxides based on Ga-O layers

DOEpatents

Dabrowski, Bogdan; Vaughey, J. T.; Poeppelmeier, Kenneth R.

1994-01-01

A high temperature superconducting material with the general formula GaSr.sub.2 Ln.sub.1-x MxCu.sub.2 O.sub.7.+-.w wherein Ln is selected from the group consisting of La, Ce, Pt, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Y and M is selected from the group consisting of Ca and Sr, 0.2.ltoreq.x.ltoreq.0.4 and w is a small fraction of one. A method of preparing this high temperature superconducting material is provided which includes heating and cooling a mixture to produce a crystalline material which is subsequently fired, ground and annealed at high pressure and temperature in oxygen to establish superconductivity.

High temperature sensor/microphone development for active noise control

NASA Technical Reports Server (NTRS)

Shrout, Thomas R.

1993-01-01

The industrial and scientific communities have shown genuine interest in electronic systems which can operate at high temperatures, among which are sensors to monitor noise, vibration, and acoustic emissions. Acoustic sensing can be accomplished by a wide variety of commercially available devices, including: simple piezoelectric sensors, accelerometers, strain gauges, proximity sensors, and fiber optics. Of the several sensing mechanisms investigated, piezoelectrics were found to be the most prevalent, because of their simplicity of design and application and, because of their high sensitivity over broad ranges of frequencies and temperature. Numerous piezoelectric materials are used in acoustic sensors today; but maximum use temperatures are imposed by their transition temperatures (T(sub c)) and by their resistivity. Lithium niobate, in single crystal form, has the highest operating temperature of any commercially available material, 650 C; but that is not high enough for future requirements. Only two piezoelectric materials show potential for use at 1000 C; AlN thin film reported to be piezoactive at 1150 C, and perovskite layer structure (PLS) materials, which possess among the highest T(sub c) (greater than 1500 C) reported for ferroelectrics. A ceramic PLS composition was chosen. The solid solution composition, 80% strontium niobate (SN) and 20% strontium tantalate (STa), with a T(sub c) approximately 1160 C, was hot forged, a process which concurrently sinters and renders the plate-like grains into a highly oriented configuration to enhance piezo properties. Poled samples of this composition showed coupling (k33) approximately 6 and piezoelectric strain constant (d33) approximately 3. Piezoactivity was seen at 1125 C, the highest temperature measurement reported for a ferroelectric ceramic. The high temperature piezoelectric responses of this, and similar PLS materials, opens the possibility of their use in electronic devices operating at temperatures up to 1000 C. Concurrent with the materials study was an effort to define issues involved in the development of a microphone capable of operation at temperatures up to 1000 C; important since microphones capable of operation above 260 C are not generally available. The distinguishing feature of a microphone is its diaphragm which receives sound from the atmosphere: whereas, most other acoustic sensors receive sound through the solid structure on which they are installed. In order to gain an understanding of the potential problems involved in designing and testing a high temperature microphone, a prototype was constructed using a commercially available lithium niobate piezoelectric element in a stainless steel structure. The prototype showed excellent frequency response at room temperature, and responded to acoustic stimulation at 670 C, above which temperature the voltage output rapidly diminished because of decreased resistivity in the element. Samples of the PLS material were also evaluated in a simulated microphone configuration, but their voltage output was found to be a few mV compared to the 10 output of the prototype.

Identification and Characterization of New Materials for Construction of Heating Plates for High-Temperature Guarded Hot Plates

NASA Astrophysics Data System (ADS)

Hameury, J.; Koenen, A.; Hay, B.; Wu, J.; Hammerschmidt, U.; Rafeld, E. K.; Pennewitz, E.; Turzó-András, E.; Strnad, R.; Blahut, A.

2018-01-01

The selection of a material for making the hot and cold plates of high-temperature guarded hot plates (HTGHPs) working up to 800°C is still an issue. The material must be machinable, have a high mechanical stability to keep the high level of flatness of the plates and have a high thermal conductivity and a high resistance to oxidation when used in air. Nickel 201 alloy has been used in several instruments, but has shown, sometimes, problems of mechanical stability. The total hemispherical emissivity of the plates must be higher than 0.8 as recommended by the standards. Three ceramic materials, a silicon infiltrated silicon carbide (SiSiC), a machinable aluminum nitride and a sintered aluminum nitride (AlN) with high thermal conductivity claimed at ambient temperature, were selected for tests in thermal conductivity and opacity to thermal radiation. Three paints withstanding high temperatures were tested in total hemispherical emissivity and durability at high temperature. Above 600°C, Nickel 201 alloy has a higher thermal conductivity than the three ceramics. Below 600°C, the SiSiC and the sintered AlN have a thermal conductivity significantly higher than Nickel 201, but the sintered AlN shows a wide transparency spectral band at short wavelengths (below 6.5 μ m). Above 300°C, the three paints have a total hemispherical emissivity above 0.8. One of the paints has polluted the specimens of an insulation material tested in thermal conductivity up to 650°C. The other two can be recommended to coat the hot and cold plates of HTGHPs used up to 800°C.

A study of the relationship between microstructure and oxidation effects in nuclear graphite at very high temperatures

NASA Astrophysics Data System (ADS)

Lo, I.-Hsuan; Tzelepi, Athanasia; Patterson, Eann A.; Yeh, Tsung-Kuang

2018-04-01

Graphite is used in the cores of gas-cooled reactors as both the neutron moderator and a structural material, and traditional and novel graphite materials are being studied worldwide for applications in Generation IV reactors. In this study, the oxidation characteristics of petroleum-based IG-110 and pitch-based IG-430 graphite pellets in helium and air environments at temperatures ranging from 700 to 1600 °C were investigated. The oxidation rates and activation energies were determined based on mass loss measurements in a series of oxidation tests. The surface morphology was characterized by scanning electron microscopy. Although the thermal oxidation mechanism was previously considered to be the same for all temperatures higher than 1000 °C, the significant increases in oxidation rate observed at very high temperatures suggest that the oxidation behavior of the selected graphite materials at temperatures higher than 1200 °C is different. This work demonstrates that changes in surface morphology and in oxidation rate of the filler particles in the graphite materials are more prominent at temperatures above 1200 °C. Furthermore, possible intrinsic factors contributing to the oxidation of the two graphite materials at different temperature ranges are discussed taking account of the dominant role played by temperature.

Development of high Tc (greater than 110K) Bi, Tl and Y-based materials as superconducting circuit elements

NASA Technical Reports Server (NTRS)

Haertling, Gene H.; Lee, Burtrand; Grabert, Gregory; Gilmour, Phillip

1991-01-01

This report is presented in two parts. Part 1 deals primarily with Bi-based materials and a small amount of work on a Y-based composition while Part 2 covers work on Tl-based materials. In Part 1, a reliable and reproducible process for producing bulk bismuth-based superconductors has been developed. It is noted however, that a percentage of the tapecast material experiences curling and fracturing after a 30 hour sintering period and is thus in need of further examination. The Bi-Sr-Ca-Cu-O (BSCCO) material has been characterized by critical temperature data, X-ray diffraction data, and surface morphology. In the case of T sub c, it is not critical to anneal the material. It appears that the BSCCO material has the possibility of producing a better grounding strap than that of the 123 material. Attempts to reproduce near room temperature superconductors in the Y-Ba-Cu-O system were unsuccessful. In Part 2, several methods of processing the high temperature superconductor Tl2Ba2Ca2Cu3O10 were investigated; i.e., different precursor compositions were sintered at various sintering times and temperatures. The highest superconductig temperature was found to be 117.8K when fired at 900 C for three hours. Higher sintering temperatures produced a melted sample which was nonsuperconducting at liquid nitrogen temperature. Also, a preliminary study found Li2O substitutions for copper appeared to increase the transition temperature and create fluxing action upon sintering. It was suggested that lower sintering temperatures might be obtained with lithium additions to produce reliable Tl2Ba2Ca2Cu3O10 processing methods.

Measurement of the Thermal Expansion Coefficient for Ultra-High Temperatures up to 3000 K

NASA Astrophysics Data System (ADS)

Kompan, T. A.; Kondratiev, S. V.; Korenev, A. S.; Puhov, N. F.; Inochkin, F. M.; Kruglov, S. K.; Bronshtein, I. G.

2018-03-01

The paper is devoted to a new high-temperature dilatometer, a part of the State Primary Standard of the thermal expansion coefficient (TEC) unit. The dilatometer is designed for investigation and certification of materials for TEC standards in the range of extremely high temperatures. The critical review of existing methods of TEC measurements is given. Also, the design, principles of operation and metrological parameters of the new device are described. The main attention is paid to the system of machine vision that allows accurate measurement of elongation at high temperatures. The results of TEC measurements for graphite GIP-4, single crystal Al2O3, and some other materials are also presented.

Candidate Materials Evaluated for a High-Temperature Stirling Convertor Heater Head

NASA Technical Reports Server (NTRS)

Bowman, Randy R.; Ritzert, Frank J.

2005-01-01

The Department of Energy and NASA have identified Stirling Radioisotope Generators (SRGs) as a candidate power system for use on long-duration, deep-space science missions and Mars rovers. One of the developments planned for an upgraded version of the current SRG design is to achieve higher efficiency by increasing the overall operating temperature of the system. Currently, the SRG operates with a heater head temperature of 650 C and is fabricated from the nickel-base superalloy 718. The current operating temperature is at the limit of alloy 718 s capability, and any planned increase in temperature will be contingent on identifying a more capable material from which to fabricate the heater head. To this end, personnel at the NASA Glenn Research Center are evaluating advanced materials for a high-temperature heater head to allow a higher convertor temperature ratio and, thus, increase the system efficiency. A generic list of properties that were used to screen the candidate materials follows: (1) creep, (2) fabricability, (3) helium gas containment, (4) long-term stability and compatibility, (5) ability to form a hermetical closeout seal, and (6) ductility and toughness.

Low Cost High Performance Nanostructured Spectrally Selective Coating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Sungho

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 guidedmore » 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.« less

Corrosion of Structural Materials for Advanced Supercritical Carbon- Dioxide Brayton Cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sridharan, Kumar

The supercritical carbon-dioxide (referred to as SC-CO 2 hereon) Brayton cycle is being considered for power conversion systems for a number of nuclear reactor concepts, including the sodium fast reactor (SFR), fluoride saltcooled high temperature reactor (FHR), and high temperature gas reactor (HTGR), and several types of small modular reactors (SMR). The SC-CO 2 direct cycle gas fast reactor has also been recently proposed. The SC-CO 2 Brayton cycle (discussed in Chapter 1) provides higher efficiencies compared to the Rankine steam cycle due to less compression work stemming from higher SC-CO 2 densities, and allows for smaller components size, fewermore » components, and simpler cycle layout. For example, in the case of a SFR using a SC-CO 2 Brayton cycle instead of a steam cycle would also eliminate the possibility of sodium-water interactions. The SC-CO 2 cycle has a higher efficiency than the helium Brayton cycle, with the additional advantage of being able to operate at lower temperatures and higher pressures. In general, the SC-CO 2 Brayton cycle is well-suited for any type of nuclear reactor (including SMR) with core outlet temperature above ~ 500°C in either direct or indirect versions. In all the above applications, materials corrosion in high temperature SC-CO 2 is an important consideration, given their expected lifetimes of 20 years or longer. Our discussions with National Laboratories and private industry early on in this project indicated materials corrosion to be one of the significant gaps in the implementation of SC-CO 2 Brayton cycle. Corrosion can lead to a loss of effective load-bearing wall thickness of a component and can potentially lead to the generation of oxide particulate debris which can lead to three-body wear in turbomachinery components. Another environmental degradation effect that is rather unique to CO 2 environment is the possibility for simultaneous occurrence of carburization during oxidation of the material. Carburization can potentially lead to embrittlement of structural alloys in SC-CO 2 Brayton cycle. An important consideration in regards to corrosion is that the temperatures can vary widely across the various sections of the SC-CO 2 Brayton cycle, from room temperature to 750°C, with even higher temperatures being desirable for higher efficiencies. Thus the extent of corrosion and corrosion mechanisms in various components and SC-CO 2 Brayton cycle will be different, requiring a judicious selection of materials for different sections of the cycle. The goal of this project was to address materials corrosion-related challenges, identify appropriate materials, and advance the body of scientific knowledge in the area of high temperature SC-CO 2 corrosion. The focus was on corrosion of materials in SC-CO 2 environment in the temperature range of 450°C to 750°C at a pressure of 2900 psi for exposure duration for up to 1000 hours. The Table below lists the materials tested in the project. The materials were selected based on their high temperature strength, their code certification status, commercial availabilities, and their prior or current usage in the nuclear reactor industry. Additionally, pure Fe, Fe-12%Cr, and Ni-22%Cr were investigated as simple model materials to more clearly understand corrosion mechanisms. This first phase of the project involved testing in research grade SC-CO 2 (99.999% purity). Specially designed autoclaves with high fidelity temperature, pressure, and flow control capabilities were built or modified for this project.« less

Cryogenic electrical properties of irradiated cyanate ester/epoxy insulation for fusion magnets

NASA Astrophysics Data System (ADS)

Li, X.; Wu, Z. X.; Li, J.; Xu, D.; Liu, H. M.; Huang, R. J.; Li, L. F.

2017-12-01

The insulation materials used in high field fusion magnets require excellent mechanical properties, high electrical breakdown strength, good thermal conductivity and high radiation tolerance. Previous investigations showed that cyanate ester/epoxy (CE/EP) insulation material, a candidate insulation for fusion magnets, can maintain good mechanical performance at cryogenic temperature after 10 MGy irradiation and has a much longer pot life than traditional epoxy insulation material. In order to quantify the electrical properties of the CE/EP insulation material at low temperature, a cryogenic electrical property testing system cooled by a G-M cryocooler was developed for this study. An insulation material with 40% cyanate ester and 60% epoxy was subjected to 60Co γ-ray irradiation in air at ambient temperature with a dose rate of 300 Gy/min, and total doses of 1 MGy, 5 MGy and 10 MGy. The electrical breakdown strength of this CE/EP insulation material was measured before and after irradiation. The results show that cryogenic temperature has a positive effect on the electrical breakdown strength of this composite, while the influence of 60Co γ-ray irradiation is not obvious at 6.1 K.

Short-term hot hardness characteristics of rolling-element steels

NASA Technical Reports Server (NTRS)

Chevalier, J. L.; Dietrich, M. W.; Zaretsky, E. V.

1972-01-01

Short-term hot hardness studies were performed with five vacuum-melted steels at temperatures from 294 to 887 K (70 to 1140 F). Based upon a minimum Rockwell C hardness of 58, the temperature limitation on all materials studied was dependent on the initial room temperature hardness and the tempering temperature of each material. For the same room temperature hardness, the short-term hot hardness characteristics were identical and independent of material composition. An equation was developed to predict the short-term hardness at temperature as a function of initial room temperature hardness for AISI 52100, as well as the high-speed tool steels.

Rare Earth Optical Temperature Sensor

NASA Technical Reports Server (NTRS)

Chubb, Donald L.; Wolford, David S.

2000-01-01

A new optical temperature sensor suitable for high temperatures (greater than 1700 K) and harsh environments is introduced. The key component of the sensor is the rare earth material contained at the end of a sensor that is in contact with the sample being measured. The measured narrow wavelength band emission from the rare earth is used to deduce the sample temperature. A simplified relation between the temperature and measured radiation was verified experimentally. The upper temperature limit of the sensor is determined by material limits to be approximately 2000 C. The lower limit, determined by the minimum detectable radiation, is found to be approximately 700 K. At high temperatures 1 K resolution is predicted. Also, millisecond response times are calculated.

Electrolytic hydriding of LaFe(13-x)Si(x) alloys for energy efficient magnetic cooling.

PubMed

Lyubina, Julia; Hannemann, Ullrich; Ryan, Mary P; Cohen, Lesley F

2012-04-17

An effective, low-temperature and readily available electrochemical method for tuning the operation temperature of LaFe(13-x)Si(x)-type alloys is demonstrated. Electrolytically hydrided materials have the same high level magnetic properties as in high temperature gas-phase processed materials and offer an advantage of higher hydrogen absorption rate in the ferromagnetic state. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

On the Use of Accelerated Aging Methods for Screening High Temperature Polymeric Composite Materials

NASA Technical Reports Server (NTRS)

Gates, Thomas S.; Grayson, Michael A.

1999-01-01

A rational approach to the problem of accelerated testing of high temperature polymeric composites is discussed. The methods provided are considered tools useful in the screening of new materials systems for long-term application to extreme environments that include elevated temperature, moisture, oxygen, and mechanical load. The need for reproducible mechanisms, indicator properties, and real-time data are outlined as well as the methodologies for specific aging mechanisms.

Emissivity of Candidate Materials for VHTR Applicationbs: Role of Oxidation and Surface Modification Treatments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sridharan, Kumar; Allen, Todd; Anderson, Mark

The Generation IV (GEN IV) Nuclear Energy Systems Initiative was instituted by the Department of Energy (DOE) with the goal of researching and developing technologies and materials necessary for various types of future reactors. These GEN IV reactors will employ advanced fuel cycles, passive safety systems, and other innovative systems, leading to significant differences between these future reactors and current water-cooled reactors. The leading candidate for the Next Generation Nuclear Plant (NGNP) to be built at Idaho National Lab (INL) in the United States is the Very High Temperature Reactor (VHTR). Due to the high operating temperatures of the VHTR,more » the Reactor Pressure Vessel (RPV) will partially rely on heat transfer by radiation for cooling. Heat expulsion by radiation will become all the more important during high temperature excursions during off-normal accident scenarios. Radiant power is dictated by emissivity, a material property. The NGNP Materials Research and Development Program Plan [1] has identified emissivity and the effects of high temperature oxide formation on emissivity as an area of research towards the development of the VHTR.« less

Heat transfer in composite materials disintegrating under high-rate one-sided heating

NASA Astrophysics Data System (ADS)

Isaev, K. B.

1993-12-01

A mathematical model of heat transfer in heat-protective materials is suggested with the proviso of a squarelaw temperature depence of the material density in the zone of thermal destruction of its binder. The influence of certain factors on the experimental temperature field and thermal conductivity of a glass-reinforced epoxy plastic material is shown.

Ceramics for Solar Receivers

NASA Technical Reports Server (NTRS)

Kudirka, A. A.

1984-01-01

Materials for high-temperature use reviewed. Report discusses characteristics of ceramics and assesses potential of candidate materials in solar receivers. Design requirements presented, including those for receiver with fluid exit temperatures up to 1,425 degrees C.

Effect of Temperature Change on Interfacial Behavior of an Acoustically Levitated Droplet

NASA Astrophysics Data System (ADS)

Kawakami, Masanori; Abe, Yutaka; Kaneko, Akiko; Yamamoto, Yuji; Hasegawa, Koji

2010-04-01

Under the microgravity environment, new and high quality materials with a homogeneous crystal structure are expected to be manufactured by undercooling solidification, since the material manufacturing under the microgravity environment is more static than that under the normal gravity. However, the temperature change on the interface of the material in space can affect on the material processing. The purpose of the present study is to investigate effect of the temperature change of interface on the large levitated droplet interface. A water droplet levitated by the acoustic standing wave is heated by YAG laser. In order to heat the water droplet by the laser heating, rhodamine 6G is solved in it to achieve high absorbance of the laser. The droplet diameter is from 4 to 5.5 mm. The deformation of the droplet interface is observed by high speed video camera. The temperature of droplet is measured by the radiation thermometer. It is noticed that the larger droplet under the higher sound pressure tends to oscillate remarkably by the laser heating.

JPRS Report; Science & Technology Japan.

DTIC Science & Technology

1989-05-02

jwmitod JPRS-JST-89-009 2 MAY 1989 SCIENCE & TECHNOLOGY JAPAN CONTENTS ADVANCED MATERIALS Properties of S-SiAlON Prepared by HIP [Kazuya...Yabuta, Hiroaki Nishio, et al.; 8TH HIGH TEMPERATURE MATERIALS KISO TORONKAI, 10-11 Nov 88] 1 Properties of SißN^-SiC Whisker Ceramics lYasuhiro...Goto, Takeyuki Yonezawa, et al,; 8TH HIGH TEMPERATURE MATERIALS KISO TORONKAI, 10-11 Nov 88] 6 Si-Nz-SiC Nanocomposites [Koichi Shinhara, Atsushi

Water-level sensor and temperature-profile detector

DOEpatents

Not Available

1981-01-29

A temperature profile detector is described which comprises a surrounding length of metal tubing and an interior electrical conductor both constructed of high temperature high electrical resistance materials. A plurality of gas-filled expandable bellows made of electrically conductive material are positioned at spaced locations along a length of the conductors. The bellows are sealed and contain a predetermined volume of a gas designed to effect movement of the bellows from an open circuit condition to a closed circuit condition in response to monitored temperature changes sensed by each bellows.

Water level sensor and temperature profile detector

DOEpatents

Tokarz, Richard D.

1983-01-01

A temperature profile detector comprising a surrounding length of metal tubing and an interior electrical conductor both constructed of high temperature high electrical resistance materials. A plurality of gas-filled expandable bellows made of electrically conductive material is electrically connected to the interior electrical conductor and positioned within the length of metal tubing. The bellows are sealed and contain a predetermined volume of a gas designed to effect movement of the bellows from an open circuit condition to a closed circuit condition in response to monitored temperature changes sensed by each bellows.

Stability and corrosion testing of a high temperature phase change material for CSP applications

NASA Astrophysics Data System (ADS)

Liu, Ming; Bell, Stuart; Tay, Steven; Will, Geoffrey; Saman, Wasim; Bruno, Frank

2016-05-01

This paper presents the stability and corrosion testing results of a candidate high temperature phase change material (PCM) for potential use in concentrating solar power applications. The investigated PCM is a eutectic mixture of NaCl and Na2CO3 and both are low cost materials. This PCM has a melting temperature of 635 °C and a relatively high latent heat of fusion of 308.1 J/g. The testing was performed by means of an electric furnace subjected to 150 melt-freeze cycles between 600 °C and 650 °C. The results showed that this PCM candidate has no obvious decomposition up to 650 °C after 150 cycles and stainless steel 316 potentially can be used as the containment material under the minimized oxygen atmosphere.

Non-contact Measurement of Creep in Ultra-High-Temperature Materials

DTIC Science & Technology

2009-11-04

Task 1: Process UHTC materials at the relevant temperatures in Electrostatic Levitation for extended periods. 5 3.5 Task 2: Prepare the required high...Electrostatic Levitation ITI Industrial Tectonics, Inc. MSFC NASA George C. Marshall Space Flight Center NASA National Aeronautics and Space...was divided into certain research questions: Can high-precision UHTC spheres be processed in Electrostatic Levitation (ESL) at the relevant

Application of the time-temperature superposition principle to the mechanical characterization of elastomeric adhesives for crash simulation purposes

NASA Astrophysics Data System (ADS)

Rauh, A.; Hinterhölzl, R.; Drechsler, K.

2012-05-01

In the automotive industry, finite element simulation is widely used to ensure crashworthiness. Mechanical material data over wide strain rate and temperature ranges are required as a basis. This work proposes a method reducing the cost of mechanical material characterization by using the time-temperature superposition principle on elastomeric adhesives. The method is based on the time and temperature interdependence which is characteristic for mechanical properties of polymers. Based on the assumption that polymers behave similarly at high strain rates and at low temperatures, a temperature-dominated test program is suggested, which can be used to deduce strain rate dependent material behavior at different reference temperatures. The temperature shift factor is found by means of dynamic mechanical analysis according to the WLF-equation, named after Williams, Landel and Ferry. The principle is applied to the viscoelastic properties as well as to the failure properties of the polymer. The applicability is validated with high strain rate tests.

Reinforcements: The key to high performance composite materials

NASA Technical Reports Server (NTRS)

Grisaffe, Salvatore J.

1990-01-01

Better high temperature fibers are the key to high performance, light weight composite materials. However, current U.S. and Japanese fibers still have inadequate high temperature strength, creep resistance, oxidation resistance, modulus, stability, and thermal expansion match with some of the high temperature matrices being considered for future aerospace applications. In response to this clear deficiency, both countries have research and development activities underway. Once successful fibers are identified, their production will need to be taken from laboratory scale to pilot plant scale. In such efforts it can be anticipated that the Japanese decisions will be based on longer term criteria than those applied in the U.S. Since the initial markets will be small, short term financial criteria may adversely minimize the number and strength of U.S. aerospace materials suppliers to well into the 21st century. This situation can only be compounded by the Japanese interests in learning to make commercial products with existing materials so that when the required advanced fibers eventually do arrive, their manufacturing skills will be developed.

Method and apparatus for altering material

DOEpatents

Stinnett, Regan W.; Greenly, John B.

2002-01-01

Methods and apparatus for thermally altering the near surface characteristics of a material are described. In particular, a repetitively pulsed ion beam system comprising a high energy pulsed power source and an ion beam generator are described which are capable of producing single species high voltage ion beams (0.25-2.5 MeV) at 1-1000 kW average power and over extended operating cycles (10.sup.8). Irradiating materials with such high energy, repetitively pulsed ion beams can yield surface treatments including localized high temperature anneals to melting, both followed by rapid thermal quenching to ambient temperatures to achieve both novel and heretofore commercially unachievable physical characteristics in a near surface layer of material.

Method and apparatus for altering material

DOEpatents

Stinnett, Regan W.; Greenly, John B.

1995-01-01

Methods and apparatus for thermally altering the near surface characteristics of a material are described. In particular, a repetitively pulsed ion beam system comprising a high energy pulsed power source and an ion beam generator are described which are capable of producing single species high voltage ion beams (0.25-2.5 MeV) at 1-1000 kW average power and over extended operating cycles (10.sup.8). Irradiating materials with such high energy, repetitively pulsed ion beams can yield surface treatments including localized high temperature anneals to melting, both followed by rapid thermal quenching to ambient temperatures to achieve both novel and heretofore commercially unachievable physical characteristics in a near surface layer of material.

Method and apparatus for altering material

DOEpatents

Stinnett, Regan W.; Greenly, John B.

2002-02-05

Methods and apparatus for thermally altering the near surface characteristics of a material are described. In particular, a repetitively pulsed ion beam system comprising a high energy pulsed power source and an ion beam generator are described which are capable of producing single species high voltage ion beams (0.25-2.5 MeV) at 1-1000 kW average power and over extended operating cycles (10.sup.8). Irradiating materials with such high energy, repetitively pulsed ion beams can yield surface treatments including localized high temperature anneals to melting, both followed by rapid thermal quenching to ambient temperatures to achieve both novel and heretofore commercially unachievable physical characteristics in a near surface layer of material.

Emerging applications of high temperature superconductors for space communications

NASA Technical Reports Server (NTRS)

Heinen, Vernon O.; Bhasin, Kul B.; Long, Kenwyn J.

1990-01-01

Proposed space missions require longevity of communications system components, high input power levels, and high speed digital logic devices. The complexity of these missions calls for a high data bandwidth capacity. Incorporation of high temperature superconducting (HTS) thin films into some of these communications system components may provide a means of meeting these requirements. Space applications of superconducting technology has previously been limited by the requirement of cooling to near liquid helium temperatures. Development of HTS materials with transition temperatures above 77 K along with the natural cooling ability of space suggest that space applications may lead the way in the applications of high temperature superconductivity. In order for HTS materials to be incorporated into microwave and millimeter wave devices, the material properties such as electrical conductivity, current density, surface resistivity and others as a function of temperature and frequency must be well characterized and understood. The millimeter wave conductivity and surface resistivity were well characterized, and at 77 K are better than copper. Basic microwave circuits such as ring resonators were used to determine transmission line losses. Higher Q values than those of gold resonator circuits were observed below the transition temperature. Several key HTS circuits including filters, oscillators, phase shifters and phased array antenna feeds are feasible in the near future. For technology to improve further, good quality, large area films must be reproducibly grown on low dielectric constant, low loss microwave substrates.

PETIs as High-Temperature Resin-Transfer-Molding Materials

NASA Technical Reports Server (NTRS)

Connell, John N.; Smith, Joseph G., Jr.; Hergenrother, Paul M.

2005-01-01

Compositions of, and processes for fabricating, high-temperature composite materials from phenylethynyl-terminated imide (PETI) oligomers by resin-transfer molding (RTM) and resin infusion have been developed. Composites having a combination of excellent mechanical properties and long-term high-temperature stability have been readily fabricated. These materials are particularly useful for the fabrication of high-temperature structures for jet-engine components, structural components on highspeed aircraft, spacecraft, and missiles. Phenylethynyl-terminated amide acid oligomers that are precursors of PETI oligomers are easily made through the reaction of a mixture of aromatic diamines with aromatic dianhydrides at high stoichiometric offsets and 4-phenylethynylphthalic anhydride (PEPA) as an end-capper in a polar solvent such as N-methylpyrrolidinone (NMP). These oligomers are subsequently cyclodehydrated -- for example, by heating the solution in the presence of toluene to remove the water by azeotropic distillation to form low-molecular-weight imide oligomers. More precisely, what is obtained is a mixture of PETI oligomeric species, spanning a range of molecular weights, that exhibits a stable melt viscosity of less than approximately 60 poise (and generally less than 10 poise) at a temperature below 300 deg C. After curing of the oligomers at a temperature of 371 deg C, the resulting polymer can have a glass-transition temperature (Tg) as high as 375 C, the exact value depending on the compositions.

High temperature support apparatus and method of use for casting materials

DOEpatents

Clark, Roger F; Cliber, James A; Stoddard, Nathan G; Gerber, Jesse I; Roberts, Raymond J; Wilmerton, Mark A

2015-02-10

This invention relates to a system and a method of use for large ceramic member support and manipulation at elevated temperatures in non-oxidizing atmospheres, such as using carbon-carbon composite materials for producing high purity silicon in the manufacture of solar modules. The high temperature apparatus of this invention includes one or more support ribs, one or more cross braces in combination with the one or more support ribs, and a shaped support liner positionable upon the one or more support ribs and the one or more cross braces.

Low temperature selective absorber research

NASA Astrophysics Data System (ADS)

Herzenberg, S. A.; Silberglitt, R.

1982-04-01

Research carried out since 1979 on selective absorbers is surveyed, with particular attention given to the low-temperature coatings seen as promising for flat plate and evacuated tube applications. The most thoroughly investigated absorber is black chrome, which is highly selective and is the most durable low-temperature absorber. It is believed that other materials, because of their low cost and lower content of strategic materials, may eventually supplant black chrome. Among these candidates are chemically converted black nickel; anodically oxidized nickel, zinc, and copper composites; and nickel or other low-cost multilayer coatings. In reviewing medium and high-temperature research, black chrome, multilayer coatings and black cobalt are seen as best medium-temperature candidates. For high temperatures, an Al2O3/Pt-Al203 multilayer composite or the zirconium diboride coating is preferred.

Ultrasonic Al₂O₃ Ceramic Thermometry in High-Temperature Oxidation Environment.

PubMed

Wei, Yanlong; Gao, Yubin; Xiao, Zhaoqian; Wang, Gao; Tian, Miao; Liang, Haijian

2016-11-11

In this study, an ultrasonic temperature measurement system was designed with Al₂O₃ high-temperature ceramic as an acoustic waveguide sensor and preliminarily tested in a high-temperature oxidation environment. The test results indicated that the system can indeed work stably in high-temperature environments. The relationship between the temperature and delay time of 26 °C-1600 °C ceramic materials was also determined in order to fully elucidate the high-temperature oxidation of the proposed waveguide sensor and to lay a foundation for the further application of this system in temperatures as high as 2000 °C.

Method for the preparation of high surface area high permeability carbons

DOEpatents

Lagasse, Robert R.; Schroeder, John L.

1999-05-11

A method for preparing carbon materials having high surface area and high macropore volume to provide high permeability. These carbon materials are prepared by dissolving a carbonizable polymer precursor, in a solvent. The solution is cooled to form a gel. The solvent is extracted from the gel by employing a non-solvent for the polymer. The non-solvent is removed by critical point drying in CO.sub.2 at an elevated pressure and temperature or evaporation in a vacuum oven. The dried product is heated in an inert atmosphere in a first heating step to a first temperature and maintained there for a time sufficient to substantially cross-link the polymer material. The cross-linked polymer material is then carbonized in an inert atmosphere.

Low temperature superconductor and aligned high temperature superconductor magnetic dipole system and method for producing high magnetic fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Ramesh; Scanlan, Ronald; Ghosh, Arup K.

A dipole-magnet system and method for producing high-magnetic-fields, including an open-region located in a radially-central-region to allow particle-beam transport and other uses, low-temperature-superconducting-coils comprised of low-temperature-superconducting-wire located in radially-outward-regions to generate high magnetic-fields, high-temperature-superconducting-coils comprised of high-temperature-superconducting-tape located in radially-inward-regions to generate even higher magnetic-fields and to reduce erroneous fields, support-structures to support the coils against large Lorentz-forces, a liquid-helium-system to cool the coils, and electrical-contacts to allow electric-current into and out of the coils. The high-temperature-superconducting-tape may be comprised of bismuth-strontium-calcium-copper-oxide or rare-earth-metal, barium-copper-oxide (ReBCO) where the rare-earth-metal may be yttrium, samarium, neodymium, or gadolinium. Advantageously, alignment of themore » large-dimension of the rectangular-cross-section or curved-cross-section of the high-temperature-superconducting-tape with the high-magnetic-field minimizes unwanted erroneous magnetic fields. Alignment may be accomplished by proper positioning, tilting the high-temperature-superconducting-coils, forming the high-temperature-superconducting-coils into a curved-cross-section, placing nonconducting wedge-shaped-material between windings, placing nonconducting curved-and-wedge-shaped-material between windings, or by a combination of these techniques.« less

Low to moderate temperature nanolaminate heater

DOEpatents

Eckels, J Del [Livermore, CA; Nunes, Peter J [Danville, CA; Simpson, Randall L [Livermore, CA; Hau-Riege, Stefan [Fremont, CA; Walton, Chris [Oakland, CA; Carter, J Chance [Livermore, CA; Reynolds, John G [San Ramon, CA

2011-01-11

A low to moderate temperature heat source comprising a high temperature energy source modified to output low to moderate temperatures wherein the high temperature energy source modified to output low to moderate temperatures is positioned between two thin pieces to form a close contact sheath. In one embodiment the high temperature energy source modified to output low to moderate temperatures is a nanolaminate multilayer foil of reactive materials that produces a heating level of less than 200.degree. C.

Optical temperature sensor using thermochromic semiconductors

DOEpatents

Kronberg, James W.

1996-01-01

An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually or by utilizing an optical fiber and an electrical sensing circuit.

Optical temperature sensor using thermochromic semiconductors

DOEpatents

Kronberg, James W.

1998-01-01

An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually using a sensor chip and an accompanying color card.

Optical temperature sensor using thermochromic semiconductors

DOEpatents

Kronberg, J.W.

1998-06-30

An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually using a sensor chip and an accompanying color card. 8 figs.

Ultrahigh-sensitive sensing platform based on p-type dumbbell-like Co3O4 network

NASA Astrophysics Data System (ADS)

Zhou, Tingting; Zhang, Tong; Zhang, Rui; Lou, Zheng; Deng, Jianan; Wang, Lili

2017-12-01

Development of high performance room temperature sensors remains a grand challenge for high demand of practical application. Metal oxide semiconductors (MOSs) have many advantages over others due to their easy functionalization, high surface area, and low cost. However, they typically need a high work temperature during sensing process. Here, p-type sensing layer is reported, consisting of pore-rich dumbbell-like Co3O4 particles (DP-Co3O4) with intrinsic high catalytic activity. The gas sensor (GS) based DP-Co3O4 catalyst exhibits ultrahigh NH3 sensing activity along with excellent stability over other structure based NH3 GSs in room temperature work environment. In addition, the unique structure of DP-Co3O4 with pore-rich and high catalytic activity endows fast gas diffusion rate and high sensitivity at room temperature. Taken together, the findings in this work highlight the merit of integrating highly active materials in p-type materials, offering a framework to develop high-sensitivity room temperature sensing platforms.

Ammonia formation caused by the presence of water in the wet grinding of silicon nitride powder

NASA Technical Reports Server (NTRS)

Kanno, Y.; Suzuki, K.; Kuwahara, Y.

1984-01-01

Si3 N4 powder (amorphous, alpha-, and beta-Si3 N4) was mixed with MeOH containing 8.87 mol. % H2O and ground. The NH3 generation rapidly increased after a grinding time of 100 hours. Silicon nitride sintered material was chosen as one of the high temperature, high strength structural materials and studies of the control of the raw material powder, preparation of the sintered body (finding the right assistant, hot press, high pressure sintering, fracture toughness and oxidation at high temperature were performed.

High Temperature Properties of an Alumina Enhanced Thermal Barrier

NASA Technical Reports Server (NTRS)

Leiser, Daniel B.; Smith, Marnell; Keating, Elizabeth A.

1987-01-01

The heatshield material requirements for future space vehicles (Aerobraking Orbital Transfer Vehicle & National Aerospace Plane) will depend upon the desired flight capability, configuration and location on the vehicle. These requirements will be more demanding and different from those derived for the materials used in the Shuttle Orbiter thermal protection system. Research was therefore initiated into improving the thermal efficiency of this class of materials by first characterizing their thermal and structural capabilities. Alternate material systems have been developed, tested, and compared with the baseline Shuttle system. This research resulted in the development of several very low density, high porosity (80-90%) materials with enhanced durability and temperature capability. One of the developments was a family of materials referred to as Fibrous Refractory Composite Insulation (FRCI) utilizing a mixture of fibers, each serving a unique purpose. One composition of the FRCI family with two fibers was adopted as a baseline material for use on the third and fourth Orbiters in selected areas due to its strength at a lower density compared to earlier materials. A further improvement in the FRCI family of materials is the Alumina Enhanced Thermal Barrier (AETB), a three-fiber composite. It has a higher temperature capability (composition dependent) than the baseline FRCI as proven by convective heating tests of one composition. AETB was studied to better characterize its performance at high temperature and the mechanisms by which its properties change. In conclusion, the shrinkage of AETB is a factor of six better than baseline FRCI at 1260 C (2300 F) with about a 20% improvement in mechanical properties. This improvement could translate into a 110 C (200 F) higher temperature capability in use as a heat shield material, but further testing in a convective heating environment is required to determine the actual improvement attainable.

CAM-7/LTO Cells for Lithium-Ion Batteries with Rapid Charging Capability at Low Temperature

DTIC Science & Technology

2012-04-06

TIAX’s high energy, high power CAM-7 cathode material, high rate capability lithium titanate (LTO) anode material, and a nitrile-cosolvent...employing TIAX’s high energy, high power CAM-7 cathode material, high rate capability lithium titanate (LTO) anode material, and a nitrile- cosolvent...electrolyte formulation. CAM-7 provides the highest energy content and rate capability of any market- ready cathode material. Commercially available

Simulation Analysis of Fluid-Structure Interaction of High Velocity Environment Influence on Aircraft Wing Materials under Different Mach Numbers.

PubMed

Zhang, Lijun; Sun, Changyan

2018-04-18

Aircraft service process is in a state of the composite load of pressure and temperature for a long period of time, which inevitably affects the inherent characteristics of some components in aircraft accordingly. The flow field of aircraft wing materials under different Mach numbers is simulated by Fluent in order to extract pressure and temperature on the wing in this paper. To determine the effect of coupling stress on the wing’s material and structural properties, the fluid-structure interaction (FSI) method is used in ANSYS-Workbench to calculate the stress that is caused by pressure and temperature. Simulation analysis results show that with the increase of Mach number, the pressure and temperature on the wing’s surface both increase exponentially and thermal stress that is caused by temperature will be the main factor in the coupled stress. When compared with three kinds of materials, titanium alloy, aluminum alloy, and Haynes alloy, carbon fiber composite material has better performance in service at high speed, and natural frequency under coupling pre-stressing will get smaller.

Study on corrosion of metal materials in nitrate molten salts

NASA Astrophysics Data System (ADS)

Zhai, Wei; Yang, Bo; Li, Maodong; Li, Shiping; Xin, Mingliang; Zhang, Shuanghong; Huang, Guojia

2017-01-01

High temperature molten salts as a heat transfer heat storage medium has been more widely used in the field of concentrated solar thermal power generation. In the thermal heat storage system, metal material stability and performance at high temperatures are of one major limitation in increasing this operating temperature. In this paper, study on corrosion of 321H, 304, 316L, P91 metal materials in modified solar two molten salts. The corrosion kinetics of 304, 316L, 321H, P91 metal material in the modified solar two molten salts at 450°C, 500°C is also investigated. Under the same condition it was found that 304, 321H corroded at a rate of 40% less than P91. Spallation of corrosion products was observed on P91 steel, while no obvious observed on other kinds of stainless steel. Corrosion rates of 304, 321H, and 316L slowly increased with temperature. Oxidation mechanisms little varied with temperature. Corrosion products of metal materials observed at 450°C, 500°C were primarily Fe oxide and Fe, Cr oxide.

Simulation Analysis of Fluid-Structure Interaction of High Velocity Environment Influence on Aircraft Wing Materials under Different Mach Numbers

PubMed Central

Sun, Changyan

2018-01-01

Aircraft service process is in a state of the composite load of pressure and temperature for a long period of time, which inevitably affects the inherent characteristics of some components in aircraft accordingly. The flow field of aircraft wing materials under different Mach numbers is simulated by Fluent in order to extract pressure and temperature on the wing in this paper. To determine the effect of coupling stress on the wing’s material and structural properties, the fluid-structure interaction (FSI) method is used in ANSYS-Workbench to calculate the stress that is caused by pressure and temperature. Simulation analysis results show that with the increase of Mach number, the pressure and temperature on the wing’s surface both increase exponentially and thermal stress that is caused by temperature will be the main factor in the coupled stress. When compared with three kinds of materials, titanium alloy, aluminum alloy, and Haynes alloy, carbon fiber composite material has better performance in service at high speed, and natural frequency under coupling pre-stressing will get smaller. PMID:29670023

Properties of Extruded PS-212 Type Self-Lubricating Materials

NASA Technical Reports Server (NTRS)

Waters, W. J.; Sliney, H. E.; Soltis, R. F.

1993-01-01

Research has been underway at the NASA Lewis Research Center since the 1960's to develop high temperature, self-lubricating materials. The bulk of the research has been done in-house by a team of researchers from the Materials Division. A series of self-lubricating solid material systems has been developed over the years. One of the most promising is the composite material system referred to as PS-212 or PM-212. This material is a powder metallurgy product composed of metal bonded chromium carbide and two solid lubricating materials known to be self-lubricating over a wide temperature range. NASA feels this material has a wide potential in industrial applications. Simplified processing of this material would enhance its commercial potential. Processing changes have the potential to reduce processing costs, but tribological and physical properties must not be adversely affected. Extrusion processing has been employed in this investigation as a consolidation process for PM-212/PS-212. It has been successful in that high density bars of EX-212 (extruded PM-212) can readily be fabricated. Friction and strength data indicate these properties have been maintained or improved over the P.M. version. A range of extrusion temperatures have been investigated and tensile, friction, wear, and microstructural data have been obtained. Results indicate extrusion temperatures are not critical from a densification standpoint, but other properties are temperature dependent.

An Investigation of Porous Structure of TiNi-Based SHS-Materials Produced at Different Initial Synthesis Temperatures

NASA Astrophysics Data System (ADS)

Khodorenko, V. N.; Anikeev, S. G.; Kokorev, O. V.; Yasenchuk, Yu. F.; Gunther, V. É.

2018-02-01

An investigation of structural characteristics and behavior of TiNi-based pore-permeable materials manufactured by the methods of selfpropagating high-temperature synthesis (SHS) at the initial synthesis temperatures T = 400 and 600°C is performed. It is shown that depending on the temperature regime, the resulting structure and properties of the material can differ. It is found out that the SHS-material produced at the initial synthesis temperature T = 400°C possesses the largest number of micropores in the pore wall surface structure due to a high phase inhomogeneity of the alloy. The regime of structure optimization of the resulting materials is described and the main stages of formation of the pore wall microporous surfaces are revealed. It is demonstrated that after optimization of the surface structure of a TiNi-based fine-pore alloy by its chemical etching, the fraction of micropores measuring in size less than 50 nm increased from 59 to 68%, while the number of pores larger than 1 μm increased twofold from 11 to 22%. In addition, peculiar features of interaction between certain cell cultures with the surface of the SHS-material manufactured at different initial synthesis temperatures are revealed. It is found out that the dynamics of the cell material integration depends on the pore wall surface morphology and dimensions of macropores.

Synthesis and Characterization of A2Mo3O 12 Materials

NASA Astrophysics Data System (ADS)

Young, Lindsay Kay

Negative thermal expansion (NTE) materials have attracted considerable research interest in recent decades. These unique materials shrink when heated, offering a potential means to control the overall thermal expansion of composites. Several families of materials display this behavior, the largest of which is the A2Mo3O12 family (also called the scandium tungstate family), in which A is a trivalent cation and M is molybdenum or tungsten. These materials show NTE in an orthorhombic structure, but many members transform to a monoclinic structure with positive expansion at low temperatures. Many properties of these materials are dependent on their elemental composition, especially the identity of the A3+ cation. This includes the magnitude of NTE, as well as the phase transition behavior as a function of temperature and pressure. It is also possible to create "mixed site" cation A2Mo3O12 materials, in which the A site is occupied by two different cations. These are described as AxA'2-xM3O12 materials, as the composition A:A' can vary. Creating these new compositions may result in different phase transition properties or the ability to tune the NTE properties of these materials. In this work, the focus was on synthesis and characterization of indium gallium molybdate (InxGa2-xM3O12). The non-hydrolytic sol-gel (NHSG) method was used to synthesize indium gallium molybdate while exploring a variety of reaction parameters. While the goal was to create stoichiometric, homogenous materials, it was found that this could not be accomplished using easily accessible parameters during NHSG reactions. However, it was discovered that certain conditions allowed unusually low temperature (230 °C) crystallization of these materials. Similar conditions were explored for single cation A2Mo3O12 materials, and it was determined that crystallization of indium molybdate, iron molybdate, and scandium molybdate was possible at temperatures of 230 or 300 °C. This extremely low temperature crystallization may provide the opportunity for exploring the in situ synthesis of polymer composites containing these materials, as the crystallization temperatures are compatible with many polymer systems. In the second part of this thesis, the high pressure behavior of a number of A2Mo3O12 and AA'Mo3O12 materials was studied. The open frameworks of NTE compounds are generally prone to pressure induced phase transitions. NTE materials may have to withstand high pressures during production or regular use of composites, thus understanding the high pressure behavior of these materials is necessary for effective application. Irreversible transitions to new phases or amorphization at high pressures could lead to failure of composites, as these phases are not expected to exhibit any NTE properties. Studies were carried out at the Advanced Photon Source at Argonne National Laboratory at pressures up to 5-7 GPa using a diamond anvil cell. The materials investigated could be divided into three groups based on distinct types of high pressure behavior. The room temperature monoclinic Group1 compounds (A2 = Al2, Fe2, FeAl, AlGa) underwent a similar sequence of reversible subtle phase transitions before undergoing a major structural transition to a common high pressure structure. The unit cell of this high pressure phase was successfully indexed, and the transition was found to be reversible upon decompression. Phase transition pressures increased with decreasing A-site cation radius. In contrast, Group2 materials (A = Cr, Y) retained their low temperature monoclinic structures up to the highest pressures investigated. The remaining materials (A2 = In2, InGa) underwent a different sequence of subtle transitions followed by an irreversible transition at higher pressures. The patterns belonging to these high pressure phases are unlike those of the first group. No patterns similar to InGaMo3O12 were found in the literature, while In2Mo3O12 may transform to the same high pressure polymorph as In2W3O12. The classification of A2Mo3O12 materials into several groups with distinct high pressure behavior adds pertinent knowledge to the field that may help elucidate the structures of previously studied materials, and ultimately may help predict the behavior of compositions that have not yet been explored.

Properties of concrete containing different type of waste materials as aggregate replacement exposed to elevated temperature – A review

NASA Astrophysics Data System (ADS)

Ghadzali, N. S.; Ibrahim, M. H. W.; Sani, M. S. H. Mohd; Jamaludin, N.; Desa, M. S. M.; Misri, Z.

2018-04-01

Concrete is the chief material of construction and it is non-combustible in nature. However, the exposure to the high temperature such as fire can lead to change in the concrete properties. Due to the higher temperature, several changes in terms of mechanical properties were observed in concrete such as compressive strength, modulus of elasticity, tensile strength and durability of concrete will decrease significantly at high temperature. The exceptional fire-proof achievement of concrete is might be due to the constituent materials of concrete such as its aggregates. The extensive use of aggregate in concrete will leads to depletion of natural resources. Hence, the use of waste and other recycled and by-product material as aggregates replacements becomes a leading research. This review has been made on the utilization of waste materials in concrete and critically evaluates its effects on the concrete performances during the fire exposure. Therefore, the objective of this paper is to review the previous search work regarding the concrete containing waste material as aggregates replacement when exposed to elevated temperature and come up with different design recommendations to improve the fire resistance of structures.

Material Problems in Using High-Temperature Thermocouples

NASA Astrophysics Data System (ADS)

Edler, F.

2011-08-01

The material compatibility and thermal stability of ceramic-composite coatings of different oxide ceramics deposited on alumina tubes to prevent the reduction of the alumina were investigated in the high-temperature range between 1750 °C and 1850 °C. It turned out that the coatings were thermally unstable and did not provide adequate protection against the reduction of the alumina tubes. The oxide ceramics formed eutectic compositions with low melting temperatures and were also prone to reduction to elementary metals by carbon. A new type of high-temperature thermocouple on the basis of refractory and noble metals was tested in the temperature range between 1325 °C and 1800 °C. Two metal-sheathed prototypes were constructed. The thermoelectric behavior of the tungsten5%rhenium/iridium thermocouples (W5%Re/Ir) was investigated by different high-temperature exposures, and the thermoelectric stability was checked by repeated measurements at the ice point.

Titanium Dioxide Volatility in High Temperature Water Vapor

NASA Technical Reports Server (NTRS)

Nguyen, QynhGiao N.

2008-01-01

Titanium (Ti) containing materials are of high interest to the aerospace industry due to its high temperature capability, strength, and light weight. As with most metals an exterior oxide layer naturally exists in environments that contain oxygen (i.e. air). At high temperatures, water vapor plays a key role in the volatility of materials including oxide surfaces. This study will evaluate cold pressed titanium dioxide (TiO2) powder pellets at a temperature range of 1400 C - 1200 C in water containing environments to determine the volatile hydroxyl species using the transpiration method. The water content ranged from 0-76 mole% and the oxygen content range was 0-100 mole % during the 20-250 hour exposure times. Preliminary results indicate that oxygen is not a key contributor at these temperatures and the following reaction is the primary volatile equation for all three temperatures: TiO2 (s) + H2O (g) = TiO(OH)2 (g).

Rare Earth Doped High Temperature Ceramic Selective Emitters

NASA Technical Reports Server (NTRS)

Chubb, Donald L.; Pal, AnnaMarie; Patton, Martin O.; Jenkins, Phillip P.

1999-01-01

As a result of their electron structure, rare earth ions in crystals at high temperature emit radiation in several narrow bands rather than in a continuous blackbody manner. This study develops a spectral emittance model for films of rare earth containing materials. Although there are several possible rare earth doped high temperature materials, this study was confined to rare earth aluminum garnets. Good agreement between experimental and theoretical spectral emittances was found for erbium, thulium and erbium-holmium aluminum garnets. Spectral emittances of these films are sensitive to temperature differences across the film. Emitter efficiency is also a sensitive function of temperature. For thulium aluminum garnet the efficiency is 0.38 at 1700 K but only 0.19 at 1262 K.

High sensitivity spectroscopic and thermal characterization of cooling efficiency for optical refrigeration materials

NASA Astrophysics Data System (ADS)

Melgaard, Seth D.; Seletskiy, Denis V.; Di Lieto, Alberto; Tonelli, Mauro; Sheik-Bahae, Mansoor

2012-03-01

Since recent demonstration of cryogenic optical refrigeration, a need for reliable characterization tools of cooling performance of different materials is in high demand. We present our experimental apparatus that allows for temperature and wavelength dependent characterization of the materials' cooling efficiency and is based on highly sensitive spectral differencing technique or two-band differential spectral metrology (2B-DSM). First characterization of a 5% w.t. ytterbium-doped YLF crystal showed quantitative agreement with the current laser cooling model, as well as measured a minimum achievable temperature (MAT) at 110 K. Other materials and ion concentrations are also investigated and reported here.

Research at Very High Pressures and High Temperatures

ERIC Educational Resources Information Center

Bundy, Francis P.

1977-01-01

Reviews research and apparatus utilized in the study of the states and characteristics of materials at very high temperatures and pressures. Includes three examples of the research being conducted. (SL)

Performance of Ceramics in Severe Environments

NASA Technical Reports Server (NTRS)

Jacobson, Nathan S.; Fox, Dennis S.; Smialek, James L.; Deliacorte, Christopher; Lee, Kang N.

2005-01-01

Ceramics are generally stable to higher temperatures than most metals and alloys. Thus the development of high temperature structural ceramics has been an area of active research for many years. While the dream of a ceramic heat engine still faces many challenges, niche markets are developing for these materials at high temperatures. In these applications, ceramics are exposed not only to high temperatures but also aggressive gases and deposits. In this chapter we review the response of ceramic materials to these environments. We discuss corrosion mechanisms, the relative importance of a particular corrodent, and, where available, corrosion rates. Most of the available corrosion information is on silicon carbide (SIC) and silicon nitride (Si3N4) monolithic ceramics. These materials form a stable film of silica (SO2) in an oxidizing environment. We begin with a discussion of oxidation of these materials and proceed to the effects of other corrodents such as water vapor and salt deposits. We also discuss oxidation and corrosion of other ceramics: precurser derived ceramics, ceramic matrix composites (CMCs), ceramics which form oxide scales other than silica, and oxide ceramics. Many of the corrosion issues discussed can be mitigated with refractory oxide coatings and we discuss the current status of this active area of research. Ultimately, the concern of corrosion is loss of load bearing capability. We discuss the effects of corrosive environments on the strength of ceramics, both monolithic and composite. We conclude with a discussion of high temperature wear of ceramics, another important form of degradation at high temperatures.

Electrodrift purification of materials for room temperature radiation detectors

DOEpatents

James, R.B.; Van Scyoc, J.M. III; Schlesinger, T.E.

1997-06-24

A method of purifying nonmetallic, crystalline semiconducting materials useful for room temperature radiation detecting devices by applying an electric field across the material is disclosed. The present invention discloses a simple technology for producing purified ionic semiconducting materials, in particular PbI{sub 2} and preferably HgI{sub 2}, which produces high yields of purified product, requires minimal handling of the material thereby reducing the possibility of introducing or reintroducing impurities into the material, is easy to control, is highly selective for impurities, retains the stoichiometry of the material and employs neither high temperatures nor hazardous materials such as solvents or liquid metals. An electric field is applied to a bulk sample of the material causing impurities present in the sample to drift in a preferred direction. After all of the impurities have been transported to the ends of the sample the current flowing through the sample, a measure of the rate of transport of mobile impurities, falls to a low, steady state value, at which time the end sections of the sample where the impurities have concentrated are removed leaving a bulk sample of higher purity material. Because the method disclosed here only acts on the electrically active impurities, the stoichiometry of the host material remains substantially unaffected. 4 figs.

Electrodrift purification of materials for room temperature radiation detectors

DOEpatents

James, Ralph B.; Van Scyoc, III, John M.; Schlesinger, Tuviah E.

1997-06-24

A method of purifying nonmetallic, crystalline semiconducting materials useful for room temperature radiation detecting devices by applying an electric field across the material. The present invention discloses a simple technology for producing purified ionic semiconducting materials, in particular PbI.sub.2 and preferably HgI.sub.2, which produces high yields of purified product, requires minimal handling of the material thereby reducing the possibility of introducing or reintroducing impurities into the material, is easy to control, is highly selective for impurities, retains the stoichiometry of the material and employs neither high temperatures nor hazardous materials such as solvents or liquid metals. An electric field is applied to a bulk sample of the material causing impurities present in the sample to drift in a preferred direction. After all of the impurities have been transported to the ends of the sample the current flowing through the sample, a measure of the rate of transport of mobile impurities, falls to a low, steady state value, at which time the end sections of the sample where the impurities have concentrated are removed leaving a bulk sample of higher purity material. Because the method disclosed here only acts on the electrically active impurities, the stoichiometry of the host material remains substantially unaffected.

Use of strainrange partitioning to predict high temperature low-cycle fatigue life. [of metallic materials

NASA Technical Reports Server (NTRS)

Hirschberg, M. H.; Halford, G. R.

1976-01-01

The fundamental concepts of the strainrange partitioning approach to high temperature, low low-cycle fatigue are reviewed. Procedures are presented by which the partitioned strainrange versus life relationships for any material can be generated. Laboratory tests are suggested for further verifying the ability of the method of strainrange partitioning to predict life.

Method and apparatus for maximizing throughput of indirectly heated rotary kilns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coates, Ralph L; Smoot, Douglas L.; Hatfield, Kent E

An apparatus and method for achieving improved throughput capacity of indirectly heated rotary kilns used to produce pyrolysis products such as shale oils or coal oils that are susceptible to decomposition by high kiln wall temperatures is disclosed. High throughput is achieved by firing the kiln such that optimum wall temperatures are maintained beginning at the point where the materials enter the heating section of the kiln and extending to the point where the materials leave the heated section. Multiple high velocity burners are arranged such that combustion products directly impact on the area of the kiln wall covered internallymore » by the solid material being heated. Firing rates for the burners are controlled to maintain optimum wall temperatures.« less

Preparation and composition of superconducting copper oxides based on Ga-O layers

DOEpatents

Dabrowski, B.; Vaughey, J.T.; Poeppelmeier, K.R.

1994-12-20

A high temperature superconducting material with the general formula GaSr[sub 2]Ln[sub 1[minus]x]M[sub x]Cu[sub 2]O[sub 7[+-]w] wherein Ln is selected from the group consisting of La, Ce, Pt, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Y and M is selected from the group consisting of C and Sr, 0.2[<=]x[<=]0.4 and w is a small fraction of one. A method of preparing this high temperature superconducting material is provided which includes heating and cooling a mixture to produce a crystalline material which is subsequently fired, ground and annealed at high pressure and temperature in oxygen to establish superconductivity. 14 figures.

Method and apparatus for maximizing throughput of indirectly heated rotary kilns

DOEpatents

Coates, Ralph L; Smoot, L. Douglas; Hatfield, Kent E

2012-10-30

An apparatus and method for achieving improved throughput capacity of indirectly heated rotary kilns used to produce pyrolysis products such as shale oils or coal oils that are susceptible to decomposition by high kiln wall temperatures is disclosed. High throughput is achieved by firing the kiln such that optimum wall temperatures are maintained beginning at the point where the materials enter the heating section of the kiln and extending to the point where the materials leave the heated section. Multiple high velocity burners are arranged such that combustion products directly impact on the area of the kiln wall covered internally by the solid material being heated. Firing rates for the burners are controlled to maintain optimum wall temperatures.

Determination of temperature dependence of full matrix material constants of PZT-8 piezoceramics using only one sample.

PubMed

Zhang, Yang; Tang, Liguo; Tian, Hua; Wang, Jiyang; Cao, Wenwu; Zhang, Zhongwu

2017-08-15

Resonant ultrasound spectroscopy (RUS) was used to determine the temperature dependence of full matrix material constants of PZT-8 piezoceramics from room temperature to 100 °C. Property variations from sample to samples can be eliminated by using only one sample, so that data self-consistency can be guaranteed. The RUS measurement system error was estimated to be lower than 2.35%. The obtained full matrix material constants at different temperatures all have excellent self-consistency, which can help accurately predict device performance at high temperatures using finite element simulations.

The effects of elevated temperatures on the structural properties of fiber composite materials suitable for use in space shuttle and other space vehicles

NASA Technical Reports Server (NTRS)

Wright, M. A.

1972-01-01

The effects of high temperatures on the structural properties of fiber composite materials for use in spacecraft structures are investigated. Various mechanical properties of boron reinforced aluminum alloys were measured. It was observed that cycling these materials through temperatures that varied from room temperature to 425 C could seriously degrade the properties. The extent of the observed effects depended on alloy type and the maximum cyclic temperature used. Results are discussed in terms of upper and lower strength bonds calculated from the strengths of individual fibers.

Material degradation due to moisture and temperature. Part 1: mathematical model, analysis, and analytical solutions

NASA Astrophysics Data System (ADS)

Xu, C.; Mudunuru, M. K.; Nakshatrala, K. B.

2016-11-01

The mechanical response, serviceability, and load-bearing capacity of materials and structural components can be adversely affected due to external stimuli, which include exposure to a corrosive chemical species, high temperatures, temperature fluctuations (i.e., freezing-thawing), cyclic mechanical loading, just to name a few. It is, therefore, of paramount importance in several branches of engineering—ranging from aerospace engineering, civil engineering to biomedical engineering—to have a fundamental understanding of degradation of materials, as the materials in these applications are often subjected to adverse environments. As a result of recent advancements in material science, new materials such as fiber-reinforced polymers and multi-functional materials that exhibit high ductility have been developed and widely used, for example, as infrastructural materials or in medical devices (e.g., stents). The traditional small-strain approaches of modeling these materials will not be adequate. In this paper, we study degradation of materials due to an exposure to chemical species and temperature under large strain and large deformations. In the first part of our research work, we present a consistent mathematical model with firm thermodynamic underpinning. We then obtain semi-analytical solutions of several canonical problems to illustrate the nature of the quasi-static and unsteady behaviors of degrading hyperelastic solids.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stewart, Gary

The primary objective of this project was to demonstrate the feasibility and reliability of utilizing high-temperature superconducting (HTS) materials in a Transmission Level Superconducting Fault Current Limiter (SFCL) application. During the project, the type of high-temperature superconducting material used evolved from 1 st generation (1G) BSCCO-2212 melt cast bulk high-temperature superconductors to 2 nd generation (2G) YBCO-based high-temperature superconducting tape. The SFCL employed SuperPower's “Matrix” technology, that offers modular features to enable scale up to transmission voltage levels. The SFCL consists of individual modules that contain elements and parallel inductors that assist in carrying the current during the fault. Amore » number of these modules are arranged in an m x n array to form the current-limiting matrix.« less

Local antiferromagnetic exchange and collaborative Fermi surface as key ingredients of high temperature superconductors

PubMed Central

Hu, Jiangping; Ding, Hong

2012-01-01

Cuprates, ferropnictides and ferrochalcogenides are three classes of unconventional high temperature superconductors, who share similar phase diagrams in which superconductivity develops after a magnetic order is suppressed, suggesting a strong interplay between superconductivity and magnetism, although the exact picture of this interplay remains elusive. Here we show that there is a direct bridge connecting antiferromagnetic exchange interactions determined in the parent compounds of these materials to the superconducting gap functions observed in the corresponding superconducting materials: in all high temperature superconductors, the Fermi surface topology matches the form factor of the pairing symmetry favored by local magnetic exchange interactions. We suggest that this match offers a principle guide to search for new high temperature superconductors. PMID:22536479

Thermodynamic Studies of High Temperature Materials Via Knudsen Cell Mass Spectrometry

NASA Technical Reports Server (NTRS)

Jacobson, Nathan S.; Brady, Michael P.

1997-01-01

The Knudsen Cell technique is a classic technique from high temperature chemistry for studying condensed phase/vapor equilibria. It is based on a small enclosure, usually about 1 cm in diameter by 1 cm high, with an orifice of well-defined geometry. This forms a molecular beam which is analyzed with mass spectrometry. There are many applications to both fundamental and applied problems with high temperature materials. Specific measurements include vapor pressures and vapor compositions above solids, activities of alloy components, and fundamental gas/solid reactions. The basic system is shown. Our system can accommodate a wide range of samples, temperatures, and attachments, such as gas inlets. It is one of only about ten such systems world-wide.

Thermal Shock Behavior of Single Crystal Oxide Refractive Concentrators for High Temperatures Solar Thermal Propulsion

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Choi, Sung R.; Jacobson, Nathan S.; Miller, Robert A.

1999-01-01

Single crystal oxides such as yttria-stabilized zirconia (Y2O3-ZrO2), yttrium-aluminum-garnet (Y3Al5O12, or YAG), magnesium oxide (MgO) and sapphire (Al2O3) have been considered as refractive secondary concentrator materials for high temperature solar propulsion applications. However, thermal mechanical reliability of the oxide components in severe thermal environments during space mission sun/shade transitions is of great concern. In this paper, critical mechanical properties of these oxide crystals are determined by the indentation technique. Thermal shock resistance of the oxides is evaluated using a high power CO, laser under high temperature-high thermal gradients. Thermal stress fracture behavior and failure mechanisms of these oxide materials are investigated under various temperature and heating conditions.

Temperature compensated high-temperature/high-pressure Merrill--Bassett diamond anvil cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schiferl, D.

1987-07-01

A Merrill--Bassett diamond anvil cell for high-temperature/high-pressure studies up to 5 GPa at 1000 K and 13 GPa at 725 K is described. To maintain uniform, well-characterized temperatures, and to protect the diamond anvils from oxidation and graphitization, the entire cell is heated in a vacuum oven. The materials are chosen so that the pressure remains constant to within +-10% over the entire temperature range.

Nanocomposite thin films for high temperature optical gas sensing of hydrogen

DOEpatents

Ohodnicki, Jr., Paul R.; Brown, Thomas D.

2013-04-02

The disclosure relates to a plasmon resonance-based method for H.sub.2 sensing in a gas stream at temperatures greater than about 500.degree. C. utilizing a hydrogen sensing material. The hydrogen sensing material is comprised of gold nanoparticles having an average nanoparticle diameter of less than about 100 nanometers dispersed in an inert matrix having a bandgap greater than or equal to 5 eV, and an oxygen ion conductivity less than approximately 10.sup.-7 S/cm at a temperature of 700.degree. C. Exemplary inert matrix materials include SiO.sub.2, Al.sub.2O.sub.3, and Si.sub.3N.sub.4 as well as modifications to modify the effective refractive indices through combinations and/or doping of such materials. At high temperatures, blue shift of the plasmon resonance optical absorption peak indicates the presence of H.sub.2. The method disclosed offers significant advantage over active and reducible matrix materials typically utilized, such as yttria-stabilized zirconia (YSZ) or TiO.sub.2.

Oxidation Characterization of Hafnium-Based Ceramics Fabricated by Hot Pressing and Electric Field-Assisted Sintering

NASA Technical Reports Server (NTRS)

Gasch, Matt; Johnson, Sylvia; Marschall, Jochen

2010-01-01

Ceramic borides, such as hafnium diboride (HfB2) and zirconium diboride (ZrB2), are members of a family of materials with extremely high melting temperatures referred to as Ultra High Temperature Ceramics (UHTCs). UHTCs constitute a class of promising materials for use in high temperature applications, such as sharp leading edges on future-generation hypersonic flight vehicles, because of their high melting points. The controlled development of microstructure has become important to the processing of UHTCs, with the prospect of improving their mechanical and thermal properties. The improved oxidation resistance of HfB2 has also become important if this material is to be successfully used at temperatures above 2000 C. Furthermore, the use of UHTCs on the leading edges of vehicles traveling at hypersonic speeds will mean exposure to a mixed oxidation environment comprised of both molecular and atomic oxygen. The current study has investigated the high-temperature oxidation behavior of HfB2-based materials in a pure O2 environment, as well as in environments containing different levels of dissociated oxygen (O/O2). Materials were processed by two techniques: conventional hot pressing (HP) and electric field-assisted sintering (FAS). Their oxidation behavior was evaluated in both a tube furnace at 1250 C for 3 hours and in a simulated re-entry environment in the Advanced Heating Facility (AHF) arcjet at NASA Ames Research Center, during a 10-minute exposure to a cold wall heat flux of 250W/sq cm and stagnation pressure of 0.1-0.2 atm. The microstructure of the different materials was characterized before and after oxidation using scanning electron microscopy (SEM).

High Temperature Stable Nanocrystalline SiGe Thermoelectric Material

NASA Technical Reports Server (NTRS)

Yang, Sherwin (Inventor); Matejczyk, Daniel Edward (Inventor); Determan, William (Inventor)

2013-01-01

A method of forming a nanocomposite thermoelectric material having microstructural stability at temperatures greater than 1000 C. The method includes creating nanocrystalline powder by cryomilling. The method is particularly useful in forming SiGe alloy powder.

Silicon Carbide Solar Cells Investigated

NASA Technical Reports Server (NTRS)

Bailey, Sheila G.; Raffaelle, Ryne P.

2001-01-01

The semiconductor silicon carbide (SiC) has long been known for its outstanding resistance to harsh environments (e.g., thermal stability, radiation resistance, and dielectric strength). However, the ability to produce device-quality material is severely limited by the inherent crystalline defects associated with this material and their associated electronic effects. Much progress has been made recently in the understanding and control of these defects and in the improved processing of this material. Because of this work, it may be possible to produce SiC-based solar cells for environments with high temperatures, light intensities, and radiation, such as those experienced by solar probes. Electronics and sensors based on SiC can operate in hostile environments where conventional silicon-based electronics (limited to 350 C) cannot function. Development of this material will enable large performance enhancements and size reductions for a wide variety of systems--such as high-frequency devices, high-power devices, microwave switching devices, and high-temperature electronics. These applications would supply more energy-efficient public electric power distribution and electric vehicles, more powerful microwave electronics for radar and communications, and better sensors and controls for cleaner-burning, more fuel-efficient jet aircraft and automobile engines. The 6H-SiC polytype is a promising wide-bandgap (Eg = 3.0 eV) semiconductor for photovoltaic applications in harsh solar environments that involve high-temperature and high-radiation conditions. The advantages of this material for this application lie in its extremely large breakdown field strength, high thermal conductivity, good electron saturation drift velocity, and stable electrical performance at temperatures as high as 600 C. This behavior makes it an attractive photovoltaic solar cell material for devices that can operate within three solar radii of the Sun.

Sintering temperature effect on electrical and thermal properties of Zn1-xAlxO as thermoelectric material candidate

NASA Astrophysics Data System (ADS)

Fajarin, Rindang; Rahel, Amelthia; Widyastuti

2018-04-01

Thermoelectric is a device to convert residual heat energy into electricity. Electrical and thermal properties of constituent material determine thermoelectric efficiency. One of metal oxides, namely zinc oxide (ZnO), is highly stable in a large temperature range, non-toxic, low cost and eco-friendly, has potential application as thermoelectric at high temperature. The aims of this study are to synthesize Zn0.98Al0.02O by coprecipitation method using ZnO and Al2O3 powders as raw materials, and to investigate the effect of sintering temperatures (at 700, 800, 900, and 950°C) on the electrical and thermal properties of the material. The sample products were analyzed by x-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive x-ray (EDX) measurements to identify phase content, to observe particle morphology and to analyze distribution of elements in the sample, respectively. LCR meter was conducted to study electrical measurements of the samples. Further, thermal properties of the samples were analyzed by TGA measurements. The data show that Al3+ ions have been successfully doped into ZnO crystal lattice and they tend to increase the electrical conductivity of the samples. The sintered Zn0.98Al0.02O sample at 900°C has the highest conductivity value (4.53 × 10-4 S/m) compared to the others. It is relatively stable at high temperature, and thus, it can be used as one promising candidate for thermoelectric material at high temperature.

Processing, Structure and High Temperature Oxidation Properties of Polymer-Derived and Hafnium Oxide Based Ceramic Systems

NASA Astrophysics Data System (ADS)

Terauds, Kalvis

Demands for hypersonic aircraft are driving the development of ultra-high temperature structural materials. These aircraft, envisioned to sustain Mach 5+, are expected to experience continuous temperatures of 1200--1800°C on the aircraft surface and temperatures as high as 2800°C in combustion zones. Breakthroughs in the development of fiber based ceramic matrix composites (CMCs) are opening the door to a new class of high-tech UHT structures for aerospace applications. One limitation with current carbon fiber or silicon carbide fiber based CMC technology is the inherent problem of material oxidation, requiring new approaches for protective environmental barrier coatings (EBC) in extreme environments. This thesis focuses on the development and characterization of SiCN-HfO2 based ceramic composite EBC systems to be used as a protective layer for silicon carbide fiber based CMCs. The presented work covers three main architectures for protection (i) multilayer films, (ii) polymer-derived HfSiCNO, and (iii) composite SiCN-HfO 2 infiltration. The scope of this thesis covers processing development, material characterization, and high temperature oxidation behavior of these three SiCN-HfO2 based systems. This work shows that the SiCN-HfO 2 composite materials react upon oxidation to form HfSiO4, offering a stable EBC in streaming air and water vapor at 1600°C.

Advanced Materials and Manufacturing for Low-Cost, High-Performance Liquid Rocket Combustion Chambers

NASA Technical Reports Server (NTRS)

Williams, Brian E.; Arrieta, Victor M.

2013-01-01

A document describes the low-cost manufacturing of C103 niobium alloy combustion chambers, and the use of a high-temperature, oxidation-resistant coating that is superior to the standard silicide coating. The manufacturing process involved low-temperature spray deposition of C103 on removable plastic mandrels produced by rapid prototyping. Thin, vapor-deposited platinum-indium coatings were shown to substantially improve oxidation resistance relative to the standard silicide coating. Development of different low-cost plastic thrust chamber mandrel materials and prototyping processes (selective laser sintering and stereolithography) yielded mandrels with good dimensional accuracy (within a couple of mils) for this stage of development. The feasibility of using the kinetic metallization cold-spray process for fabrication of free-standing C1O3 thrusters on removable plastic mandrels was also demonstrated. The ambient and elevated temperature mechanical properties of the material were shown to be reasonably good relative to conventionally processed C103, but the greatest potential benefit is that coldsprayed chambers require minimal post-process machining, resulting in substantially lower machining and material costs. The platinum-iridium coating was shown to provide greatly increased oxidation resistance over the silicide when evaluated through oxyacetylene torch testing to as high as 300 F (= 150 C). The iridium component minimizes reaction with the niobium alloy chamber at high temperatures, and provides the high-temperature oxidation resistance needed at the throat.

Preparation of Microcellular Epoxy Foams through a Limited-Foaming Process: A Contradiction with the Time-Temperature-Transformation Cure Diagram.

PubMed

Wang, Lijun; Zhang, Chun; Gong, Wei; Ji, Yubi; Qin, Shuhao; He, Li

2018-01-01

3D cross-linking networks are generated through chemical reactions between thermosetting epoxy resin and hardener during curing. The curing degree of epoxy material can be increased by increasing curing temperature and/or time. The epoxy material must then be fully cured through a postcuring process to optimize its material characteristics. Here, a limited-foaming method is introduced for the preparation of microcellular epoxy foams (Lim-foams) with improved cell morphology, high thermal expansion coefficient, and good compressive properties. Lim-foams exhibit a lower glass transition temperature (T g ) and curing degree than epoxy foams fabricated through free-foaming process (Fre-foams). Surprisingly, however, the T g of Lim-foams is unaffected by postcuring temperature and time. This phenomenon, which is related to high gas pressure in the bubbles, contradicts that indicated by the time-temperature-transformation cure diagram. High bubble pressure promotes the movement of molecular chains under heating at low temperature and simultaneously suppresses the etherification cross-linking reaction during post-curing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optical temperature sensor using thermochromic semiconductors

DOEpatents

Kronberg, J.W.

1996-08-20

An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually or by utilizing an optical fiber and an electrical sensing circuit. 7 figs.

A continuum deformation theory for metal-matrix composites at high temperature

NASA Technical Reports Server (NTRS)

Robinson, D. N.

1987-01-01

A continuum theory is presented for representing the high temperature, time dependent, hereditary deformation behavior of metallic composites that can be idealized as pseudohomogeneous continua with locally definable directional characteristics. Homogenization of textured materials (molecular, granular, fibrous) and applicability of continuum mechanics in structural applications depends on characteristic body dimensions, the severity of gradients (stress, temperature, etc.) in the structure and the relative size of the internal structure (cell size) of the material. The point of view taken here is that the composite is a material in its own right, with its own properties that can be measured and specified for the composite as a whole.

Feasibility of Kevlar 49/PMR-15 Polyimide for High Temperature Applications

NASA Technical Reports Server (NTRS)

Hanson, M. P.

1980-01-01

Kevlar 49 aramid organic fiber reinforced PMR-15 polyimide laminates were characterized to determine the applicability of the material to high temperature aerospace structures. Kevlar 49/3501-6 epoxy laminates were fabricated and characterized for comparison with the Kevlar 49/PMR-15 polyimide material. Flexural strengths and moduli and interlaminar shear strengths were determined from 75 F to 600 F for the PMR-15 and from 75 F to 450 F for the Kevlar/3501-6 epoxy material. The effects of hydrothermal and long-term elevated temperature exposures on the flexural strengths and moduli and the interlaminar shear strengths were also studied.

Feasibility of Kevlar 49/PMR-15 polyimide for high temperature applications

NASA Technical Reports Server (NTRS)

Hanson, M. P.

1980-01-01

Kevlar 49 aramid organic fiber reinforced PMR-15 polyimide laminates were characterized to determine the applicability of the material to high temperature aerospace structures. Kevlar 49/3501-6 epoxy laminates were fabricated and characterized for comparison with the Kevlar 49/PMR-15 polyimide material. Flexural strengths and moduli and interlaminar shear strengths were determined from 75 to 600 F for the PMR-15 and from 75 to 450 F for the Kevlar 49/3501-6 epoxy material. The study also included the effects of hydrothermal and long-term elevated temperature exposures on the flexural strengths and moduli and the interlaminar shear strengths.

Plasma-Sprayed Refractory Oxide Coatings on Silicon-Base Ceramics

NASA Technical Reports Server (NTRS)

Tewari, Surendra

1997-01-01

Silicon-base ceramics are promising candidate materials for high temperature structural applications such as heat exchangers, gas turbines and advanced internal combustion engines. Composites based on these materials are leading candidates for combustor materials for HSCT gas turbine engines. These materials possess a combination of excellent physical and mechanical properties at high temperatures, for example, high strength, high toughness, high thermal shock resistance, high thermal conductivity, light weight and excellent oxidation resistance. However, environmental durability can be significantly reduced in certain conditions such as when molten salts, H2 or water vapor are present. The oxidation resistance of silicon-base materials is provided by SiO2 protective layer. Molten salt reacts with SiO2 and forms a mixture of SiO2 and liquid silicate at temperatures above 800C. Oxygen diffuses more easily through the chemically altered layer, resulting in a catastrophic degradation of the substrate. SiC and Si3N4 are not stable in pure H2 and decompose to silicon and gaseous species such as CH4, SiH, SiH4, N2, and NH3. Water vapor is known to slightly increase the oxidation rate of SiC and Si3N4. Refractory oxides such as alumina, yttria-stabilized zirconia, yttria and mullite (3Al2O3.2SiO2) possess excellent environmental durability in harsh conditions mentioned above. Therefore, refractory oxide coatings on silicon-base ceramics can substantially improve the environmental durability of these materials by acting as a chemical reaction barrier. These oxide coatings can also serve as a thermal barrier. The purpose of this research program has been to develop refractory oxide chemical/thermal barrier coatings on silicon-base ceramics to provide extended temperature range and lifetime to these materials in harsh environments.

The experimental evaluation and application of high-temperature solid lubricants. Ph.D. Thesis - Case Western Reserve Univ., 1989 Final Report

NASA Technical Reports Server (NTRS)

Dellacorte, Christopher

1990-01-01

A research program is described which developes an understanding of high-temperature solid lubrication and experimental techniques through the development of a composite lubricant coating system. The knowledge gained through this research was then applied to a specific engineering challenge, the tribology of a sliding seal for hypersonic flight vehicles. The solid lubricant coating is a chromium carbide based composite combined with silver, which acts as a low temperature lubricant, and barium fluoride/calcium fluoride eutectic, which acts as a high-temperature lubricant. This composite coating provides good wear resistance and low friction for sliding contacts from room temperature to over 900 C in reducing or oxidative environments. The specific research on this coating included a composition screening using a foil gas bearing test rig and the use of thin silver films to reduce initial wear using a pin-on-disk test rig. The chemical stability of the materials used was also addressed. This research indicated that soft metallic films and materials which become soft at elevated temperatures are potentially good lubricants. The general results from the experiments with the model solid lubricant coating were then applied to a sliding seal design concept. This seal design requires that a braided ceramic fabric slide against a variety of metal counterface materials at temperatures from 25 to 850 C in an oxidative environment. A pin-on-disk tribometer was used to evaluate the tribological properties of these materials and to develop lubrication techniques. The results indicate that these seal materials must be lubricated to prevent wear and reduce friction. Thin films of silver, gold and calcium fluoride provided lubrication to the sliding materials.

Attachment of Free Filament Thermocouples for Temperature Measurements on CMC

NASA Technical Reports Server (NTRS)

Lei, Jih-Fen; Cuy, Michael D.; Wnuk, Stephen P.

1997-01-01

Ceramic Matrix Composites (CMC) are being developed for use as enabling materials for advanced aeropropulsion engine and high speed civil transport applications. The characterization and testing of these advanced materials in hostile, high-temperature environments require accurate measurement of the material temperatures. Commonly used wire Thermo-Couples (TC) can not be attached to this ceramic based material via conventional spot-welding techniques. Attachment of wire TC's with commercially available ceramic cements fail to provide sufficient adhesion at high temperatures. While advanced thin film TC technology provides minimally intrusive surface temperature measurement and has good adhesion on the CMC, its fabrication requires sophisticated and expensive facilities and is very time consuming. In addition, the durability of lead wire attachments to both thin film TC's and the substrate materials requires further improvement. This paper presents a newly developed attachment technique for installation of free filament wire TC's with a unique convoluted design on ceramic based materials such as CMC's. Three CMC's (SiC/SiC CMC and alumina/alumina CMC) instrumented with type IC, R or S wire TC's were tested in a Mach 0.3 burner rig. The CMC temperatures measured from these wire TC's were compared to that from the facility pyrometer and thin film TC's. There was no sign of TC delamination even after several hours exposure to 1200 C. The test results proved that this new technique can successfully attach wire TC's on CMC's and provide temperature data in hostile environments. The sensor fabrication process is less expensive and requires very little time compared to that of the thin film TC's. The same installation technique/process can also be applied to attach lead wires for thin film sensor systems.

A new in vivo screening model for posterior spinal bone formation: comparison of ten calcium phosphate ceramic material treatments.

PubMed

Wilson, Clayton E; Kruyt, Moyo C; de Bruijn, Joost D; van Blitterswijk, Clemens A; Oner, F Cumhur; Verbout, Abraham J; Dhert, Wouter J A

2006-01-01

This study presents a new screening model for evaluating the influence of multiple conditions on the initial process of bone formation in the posterior lumbar spine of a large animal. This model uses cages designed for placement on the decorticated transverse process of the goat lumbar spine. Five conduction channels per cage, each be defined by a different material treatment, are open to both the underlying bone and overlying soft tissue. The model was validated in ten adult Dutch milk goats, with each animal implanted with two cages containing a total of ten calcium phosphate material treatments according to a randomized complete block design. The ten calcium phosphate ceramic materials were created through a combination of material chemistry (BCP, TCP, HA), sintering temperature (low, medium, high), calcination and surface roughness treatments. To monitor the bone formation over time, fluorochrome markers were administered at 3, 5 and 7 weeks and the animals were sacrificed at 9 weeks after implantation. Bone formation in the conduction channels was investigated by histology and histomorphometry of non-decalcified sections using traditional light and epifluorescent microscopy. According to both observed and measured bone formation parameters, materials were ranked in order of increasing magnitude as follows: low sintering temperature BCP (rough and smooth) approximately medium sintering temperature BCP approximately = TCP > calcined low sintering temperature HA > non-calcined low sintering temperature HA > high sintering temperature BCP (rough and smooth) > high sintering temperature HA (calcined and non-calcined). These results agree closely with those obtained in previous studies of osteoconduction and bioactivity of ceramics thereby validating the screening model presented in this study.

Making High-Temperature Superconductors By Melt Sintering

NASA Technical Reports Server (NTRS)

Golben, John P.

1992-01-01

Melt-sintering technique applied to YBa2Cu3O7-x system and to Bi/Ca/Sr/Cu-oxide system to produce highly oriented bulk high-temperature-superconductor materials extending to macroscopically usable dimensions. Processing requires relatively inexpensive and simple equipment. Because critical current two orders of magnitude greater in crystal ab plane than in crystal c direction, high degree of orientation greatly enhances critical current in these bulk materials, making them more suitable for many proposed applications.

The potential for CMCs to replace superalloys in engine exhaust ducts

NASA Astrophysics Data System (ADS)

Roth, Richard; Clark, Joel P.; Field, Frank R.

1994-01-01

The Materials Systems Laboratory at the Massachusetts Institute of Technology has conducted research to develop decision tools that can facilitate materials selection and provide a deeper understanding of the design tradeoffs that occur when choosing among advanced aerospace materials for high-temperature applications. As an illustration of the use of these tools, this paper describes research done to evaluate the material alternatives currently under consideration for exhaust ducts in aircraft gas turbine engines. Although nickel-based superalloys currently prevail for this application, the increasing temperatures of modern engines are necessitating the usage of higher temperature materials.

Airframe materials for HSR

NASA Technical Reports Server (NTRS)

Bales, Thomas T.

1992-01-01

Vugraphs are presented to show the use of refractory materials for the skin of the High speed Civil Transport (HSCT). Examples are given of skin temperature ranges, failure mode weight distribution, tensile properties as a function of temperature, and components to be constructed from composite materials. The responsibilities of various aircraft companies for specific aircraft components are defined.

Advances in processing of NiAl intermetallic alloys and composites for high temperature aerospace applications

NASA Astrophysics Data System (ADS)

Bochenek, Kamil; Basista, Michal

2015-11-01

Over the last few decades intermetallic compounds such as NiAl have been considered as potential high temperature structural materials for aerospace industry. A large number of investigations have been reported describing complex fabrication routes, introducing various reinforcing/alloying elements along with theoretical analyses. These research works were mainly focused on the overcoming of main disadvantage of nickel aluminides that still restricts their application range, i.e. brittleness at room temperature. In this paper we present an overview of research on NiAl processing and indicate methods that are promising in solving the low fracture toughness issue at room temperature. Other material properties relevant for high temperature applications are also addressed. The analysis is primarily done from the perspective of NiAl application in aero engines in temperature regimes from room up to the operating temperature (over 1150 °C) of turbine blades.

Optical fiber evanescent absorption sensors for high-temperature gas sensing in advanced coal-fired power plants

NASA Astrophysics Data System (ADS)

Buric, Michael P.; Ohodnicky, Paul R.; Duy, Janice

2012-10-01

Modern advanced energy systems such as coal-fired power plants, gasifiers, or similar infrastructure present some of the most challenging harsh environments for sensors. The power industry would benefit from new, ultra-high temperature devices capable of surviving in hot and corrosive environments for embedded sensing at the highest value locations. For these applications, we are currently exploring optical fiber evanescent wave absorption spectroscopy (EWAS) based sensors consisting of high temperature core materials integrated with novel high temperature gas sensitive cladding materials. Mathematical simulations can be used to assist in sensor development efforts, and we describe a simulation code that assumes a single thick cladding layer with gas sensitive optical constants. Recent work has demonstrated that Au nanoparticle-incorporated metal oxides show a potentially useful response for high temperature optical gas sensing applications through the sensitivity of the localized surface plasmon resonance absorption peak to ambient atmospheric conditions. Hence, the simulation code has been applied to understand how such a response can be exploited in an optical fiber based EWAS sensor configuration. We demonstrate that interrogation can be used to optimize the sensing response in such materials.

46 CFR 56.60-5 - Steel (High temperature applications).

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Steel (High temperature applications). 56.60-5 Section... SYSTEMS AND APPURTENANCES Materials § 56.60-5 Steel (High temperature applications). (a) (Reproduces 124.2... steel, plain nickel-alloy steel, carbon-manganese-alloy steel, manganese-vanadium-alloy steel, and...

46 CFR 56.60-5 - Steel (High temperature applications).

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Steel (High temperature applications). 56.60-5 Section... SYSTEMS AND APPURTENANCES Materials § 56.60-5 Steel (High temperature applications). (a) (Reproduces 124.2... steel, plain nickel-alloy steel, carbon-manganese-alloy steel, manganese-vanadium-alloy steel, and...

46 CFR 56.60-5 - Steel (High temperature applications).

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Steel (High temperature applications). 56.60-5 Section... SYSTEMS AND APPURTENANCES Materials § 56.60-5 Steel (High temperature applications). (a) (Reproduces 124.2... steel, plain nickel-alloy steel, carbon-manganese-alloy steel, manganese-vanadium-alloy steel, and...

46 CFR 56.60-5 - Steel (High temperature applications).

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Steel (High temperature applications). 56.60-5 Section... SYSTEMS AND APPURTENANCES Materials § 56.60-5 Steel (High temperature applications). (a) (Reproduces 124.2... steel, plain nickel-alloy steel, carbon-manganese-alloy steel, manganese-vanadium-alloy steel, and...

46 CFR 56.60-5 - Steel (High temperature applications).

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Steel (High temperature applications). 56.60-5 Section... SYSTEMS AND APPURTENANCES Materials § 56.60-5 Steel (High temperature applications). (a) (Reproduces 124.2... steel, plain nickel-alloy steel, carbon-manganese-alloy steel, manganese-vanadium-alloy steel, and...

High Accuracy Thermal Expansion Measurement At Cryogenic Temperatures

NASA Technical Reports Server (NTRS)

Stallcup, Michael; Presson, Joan; Tucker, James; Daspit, Gregory; Nein, Max

2003-01-01

A new, interferometer based system for measuring thermal expansion to an absolute accuracy of 20 ppb or better at cryogenic temperatures has been developed. Data from NIST Copper SRM 736 measured from room temperature to 15 K will be presented along with data from many other materials including beryllium, ULE, Zerodur, and composite materials. Particular attention will be given to a study by the Space Optics Manufacturing Technology Center (SOMTC) investigating the variability of ULE and beryllium materials used in the AMSD program. Approximately 20 samples of each material, tested from room temperature to below 30 K are compared as a function of billet location.

High Accuracy Thermal Expansion Measurement at Cryogenic Temperatures

NASA Technical Reports Server (NTRS)

Tucker, Jim; Despit, Gregory; Stallcup, Michael; Presson, Joan; Nein, Max

2003-01-01

A new, interferometer-based system for measuring thermal expansion to an absolute accuracy of 20 ppb or better at cryogenic temperatures has been developed. Data from NIST Copper SRM 736 measured from room temperature to 15 K will be presented along with data from many other materials including beryllium, ULE, Zerodur, and composite materials. Particular attention will be given to a study by the Space Optics Manufacturing Technology Center (SOMTC) investigating the variability of ULE and beryllium materials used in the AMSD program Approximately 20 samples of each material, tested from room temperature to below 30 K are compared as a function of billet location.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sibley, L.B.; Mace, A.E.; Grieser, D.R.

Various ceramic and cermet materials were evaluated for unlubricated wear resistance at high sliding speed (100 to 200 fps) and low unit load (5to 50 psi) in 1000 to 1800 deg F air. A statistical correlation was obtained between the measured wear rates under these conditions and the coefficient of friction, the thermal-stress resistance, and the thermal dlffusivity of the mated materials on which wear predominated. A mechanism of wear was evolved based on the above correlation and on the experimental study of friction and wear surface- temperature fluctuations using special transducers and color-motion-picture photography. During high-speed sliding, wear appearsmore » to be induced by the inability of ceramic and cermet materials to resist thermal stresses produced by temperature gradients within each rubbing surface between small asperities or hot spots. in frictional contact and the body of the respective materials. In this situation the wear rate is influenced both by the configuration of the rubbing pants and by the thermalstress-resistance properties of the materials. Promising materials for high-temperature high-speed sliding bearings and seals include Al/ sub 2/O/sub 3/-Cr-Mo cermets, SiC ceramics, and TiC-Ni-Mo cermets. (auth)« less

Combustion synthesis of ceramic-metal composite materials in microgravity

NASA Technical Reports Server (NTRS)

Moore, John

1995-01-01

Combustion synthesis, self-propagating high temperature synthesis (SHS) or reactive synthesis provides an attractive alternative to conventional methods of producing advanced materials since this technology is based on the ability of highly exothermic reactions to be self sustaining and, therefore, energetically efficient. The exothermic SHS reaction is initiated at the ignition temperature, T(sub ig), and generates heat which is manifested in a maximum or combustion temperature, T(sub c), which can exceed 3000 K . Such high combustion temperatures are capable of melting and/or volatilizing reactant and product species and, therefore, present an opportunity for producing structure and property modification and control through liquid-solid, vapor-liquid-solid, and vapor-solid transformations.

The total hemispheric emissivity of painted aluminum honeycomb at cryogenic temperatures

NASA Astrophysics Data System (ADS)

Tuttle, J.; Canavan, E.; DiPirro, M.; Li, X.; Knollenberg, P.

2014-01-01

NASA uses high-emissivity surfaces on deep-space radiators and thermal radiation absorbers in test chambers. Aluminum honeycomb core material, when coated with a high-emissivity paint, provides a lightweight, mechanically robust, and relatively inexpensive black surface that retains its high emissivity down to low temperatures. At temperatures below about 100 Kelvin, this material performs much better than the paint itself. We measured the total hemispheric emissivity of various painted honeycomb configurations using an adaptation of an innovative technique developed for characterizing thin black coatings. These measurements were performed from room temperature down to 30 Kelvin. We describe the measurement technique and compare the results with predictions from a detailed thermal model of each honeycomb configuration.

The Total Hemispheric Emissivity of Painted Aluminum Honeycomb at Cryogenic Temperatures

NASA Technical Reports Server (NTRS)

Tuttle, J.; Canavan, E.; DiPirro, M.; Li, X.; Knollenberg, K.

2013-01-01

NASA uses high-emissivity surfaces on deep-space radiators or thermal radiation absorbers in test chambers. Aluminum honeycomb core material, when coated with a high-emissivity paint, provides a lightweight, mechanically robust, and relatively inexpensive black surface that retains its high emissivity down to low temperatures. At temperatures below about 100 Kelvin, this material performs much better than the paint itself. We measured the total hemispheric emissivity of various painted honeycomb configurations using an adaptation of an innovative technique developed for characterizing thin black coatings. These measurements were performed from room temperature down to 30 Kelvin. We describe the measurement technique and compare the results with predictions from a detailed thermal model of each honeycomb configuration.

High-Performance Flexible Force and Temperature Sensing Array with a Robust Structure

NASA Astrophysics Data System (ADS)

Kim, Min-Seok; Song, Han-Wook; Park, Yon-Kyu

We have developed a flexible tactile sensor array capable of sensing physical quantities, e.g. force and temperature with high-performances and high spatial resolution. The fabricated tactile sensor consists of 8 × 8 force measuring array with 1 mm spacing and a thin metal (copper) temperature sensor. The flexible force sensing array consists of sub-millimetre-size bar-shaped semi-conductor strain gage array attached to a thin and flexible printed circuit board covered by stretchable elastomeric material on both sides. This design incorporates benefits of both materials; the semi-conductor's high performance and the polymer's mechanical flexibility and robustness, while overcoming their drawbacks of those two materials. Special fabrication processes, so called “dry-transfer technique” have been used to fabricate the tactile sensor along with standard micro-fabrication processes.

Effects of elevated temperatures on different restorative materials: An aid to forensic identification processes

PubMed Central

Pol, Chetan A.; Ghige, Suvarna K.; Gosavi, Suchitra R.; Hazarey, Vinay K.

2015-01-01

Background: Heat-induced alterations to dental and restorative materials can be of great interest to forensic dentistry. Knowing the specific optical behavior of dental materials can be of high importance as recognition of changes induced by high temperatures can lead to the determination of material which was used in a dental restoration, facilitating identification of burned human remains. Aim: To observe the effects of predetermined temperatures (200°C–400°C–600°C–800°C–1000°C) on unrestored teeth and different restorative materials macroscopically and then examine them under a stereomicroscope for the purpose of identification. Materials and Methods: The study was conducted on 375 extracted teeth which were divided into five groups of 75 teeth each as follows: group 1- unrestored teeth, group 2- teeth restored with all-ceramic crowns, Group 3- with class I silver amalgam filling, group 4- with class I composite restoration, and group 5- with class I glass ionomer cement restoration. Results: Unrestored and restored teeth display a series of specific macroscopic & stereomicroscopic structural changes for each range of temperature. Conclusion: Dental tissues and restorative materials undergo a series of changes which correlate well with the various temperatures to which they were exposed. These changes are a consequence of the nature of the materials and their physicochemical characteristics. PMID:26005305

High Temperature Materials for Chemical Propulsion Applications

NASA Technical Reports Server (NTRS)

Elam, Sandra; Hickman, Robert; O'Dell, Scott

2007-01-01

Radiation or passively cooled thrust chambers are used for a variety of chemical propulsion functions including apogee insertion, reaction control for launch vehicles, and primary propulsion for planetary spacecraft. The performance of these thrust chambers is limited by the operating temperature of available materials. Improved oxidation resistance and increased operating temperatures can be achieved with the use of thermal barrier coatings such as zirconium oxide (ZrO2) and hafnium oxide (HfO2). However, previous attempts to include these materials showed cracking and spalling of the oxide layer due to poor bonding. Current research at NASA's Marshall Space Flight Center (MSFC) has generated unique, high temperature material options for in-space thruster designs that are capable of up to 2500 C operating temperatures. The research is focused on fabrication technologies to form low cost Iridium,qF_.henium (Ir/Re) components with a ceramic hot wall created as an integral, functionally graded material (FGM). The goal of this effort is to further de?celop proven technologies for embedding a protective ceramic coating within the Ir/Re liner to form a robust functional gradient material. Current work includes the fabrication and testing of subscale samples to evaluate tensile, creep, thermal cyclic/oxidation, and thermophysical material properties. Larger test articles have also being fabricated and hot-fire tested to demonstrate the materials in prototype thrusters at 1O0 lbf thrust levels.

The metallurgy of high temperature alloys

NASA Technical Reports Server (NTRS)

Tien, J. K.; Purushothaman, S.

1976-01-01

Nickel-base, cobalt-base, and high nickel and chromium iron-base alloys are dissected, and their microstructural and chemical components are assessed with respect to the various functions expected of high temperature structural materials. These functions include the maintenance of mechanical integrity over the strain-rate spectrum from creep resistance through fatigue crack growth resistance, and such alloy stability expectations as microstructural coarsening resistance, phase instability resistance and oxidation and corrosion resistance. Special attention will be given to the perennial conflict and trade-off between strength, ductility and corrosion and oxidation resistance. The newest developments in the constitution of high temperature alloys will also be discussed, including aspects relating to materials conservation.

A high temperature testing system for ceramic composites

NASA Technical Reports Server (NTRS)

Hemann, John

1994-01-01

Ceramic composites are presently being developed for high temperature use in heat engine and space power system applications. The operating temperature range is expected to be 1090 to 1650 C (2000 F to 3000 F). Very little material data is available at these temperatures and, therefore, it is desirable to thoroughly characterize the basic unidirectional fiber reinforced ceramic composite. This includes testing mainly for mechanical material properties at high temperatures. The proper conduct of such characterization tests requires the development of a tensile testing system includes unique gripping, heating, and strain measuring devices which require special considerations. The system also requires an optimized specimen shape. The purpose of this paper is to review various techniques for measuring displacements or strains, preferably at elevated temperatures. Due to current equipment limitations it is assumed that the specimen is to be tested at a temperature of 1430 C (2600F) in an oxidizing atmosphere. For the most part, previous high temperature material characterization tests, such as flexure and tensile tests, have been performed in inert atmospheres. Due to the harsh environment in which the ceramic specimen is to be tested, many conventional strain measuring techniques can not be applied. Initially a brief description of the more commonly used mechanical strain measuring techniques is given. Major advantages and disadvantages with their application to high temperature tensile testing of ceramic composites are discussed. Next, a general overview is given for various optical techniques. Advantages and disadvantages which are common to these techniques are noted. The optical methods for measuring strain or displacement are categorized into two sections. These include real-time techniques. Finally, an optical technique which offers optimum performance with the high temperature tensile testing of ceramic composites is recommended.

Method for the preparation of high surface area high permeability carbons

DOEpatents

Lagasse, R.R.; Schroeder, J.L.

1999-05-11

A method for preparing carbon materials having high surface area and high macropore volume to provide high permeability. These carbon materials are prepared by dissolving a carbonizable polymer precursor, in a solvent. The solution is cooled to form a gel. The solvent is extracted from the gel by employing a non-solvent for the polymer. The non-solvent is removed by critical point drying in CO{sub 2} at an elevated pressure and temperature or evaporation in a vacuum oven. The dried product is heated in an inert atmosphere in a first heating step to a first temperature and maintained there for a time sufficient to substantially cross-link the polymer material. The cross-linked polymer material is then carbonized in an inert atmosphere. 3 figs.

Investigation of the Environmental Durability of a Powder Metallurgy Material

NASA Technical Reports Server (NTRS)

Ward, LaNita D.

2004-01-01

PM304 is a NASA-developed composite powder metallurgy material that is being developed for high temperature applications such as bushings in high temperature industrial furnace conveyor systems. My goal this summer was to analyze and evaluate the effects that heat exposure had on the PM304 material at 500 C and 650 C. The material is composed of Ni-Cr, Ag, Cr2O3, and eutectic BaF2-CaF2. PM304 is designed to eliminate the need for oil based lubricants in high temperature applications, while reducing friction and wear. However, further investigation was needed to thoroughly examine the properties of PM304. The effects of heat exposure on PM304 bushings were investigated. This investigation was necessary due to the high temperatures that the material would be exposed to in a typical application. Each bushing was cut into eight sections. The specimens were heated to 500 C or 650 C for time intervals from 1 hr to 5,000 hrs. Control specimens were kept at room temperature. Weight and thickness measurements were taken before and after the bushing sections were exposed to heat. Then the heat treated specimens were mounted and polished side by side with the control specimens. This enabled optical examination of the material's microstructure using a metallograph. The specimens were also examined with a scanning electron microscope (SEM). The microstructures were compared to observe the effects of the heat exposure. Chemical analysis was done to investigate the interactions between Ni-Cr and BaF2-CaF2 and between Cr2O3 and BaF2-CaF2 at high temperature. To observe this, the two compounds that were being analyzed were mixed in a crucible in varied weight percentages and heated to 1100 C in a furnace for approximately two hours. Then the product was allowed to cool and was then analyzed by X-ray diffraction. Interpretation of the results is in progress.

Lightweight Ceramics for Aeroacoustic Applications

NASA Technical Reports Server (NTRS)

Kwan, H. W.; Spamer, G. T.; Yu, J.; Yasukawa, B.

1997-01-01

The use of a HTP (High Temperature Performance) ceramic foam for aeroacoustic applications is investigated. HTP ceramic foam is a composition of silica and alumina fibers developed by LMMS. This foam is a lightweight high-temperature fibrous bulk material with small pore size, ultra high porosity, and good strength. It can be used as a broadband noise absorber at both room and high temperature (up to 1800 F). The investigation included an acoustic assessment as well as material development, and environmental and structural evaluations. The results show that the HTP ceramic foam provides good broadband noise absorbing capability and adequate strength when incorporating the HTP ceramic foam system into a honeycomb sandwich structure. On the other hand, the material is sensitive to Skydrol and requires further improvements. Good progress has been made in the impedance model development. A relationship between HTP foam density, flow resistance, and tortuosity will be established in the near future. Additional effort is needed to investigate the coupling effects between face sheet and HTP foam material.

Numerical Simulation of Thermal Performance of Glass-Fibre-Reinforced Polymer

NASA Astrophysics Data System (ADS)

Zhao, Yuchao; Jiang, Xu; Zhang, Qilin; Wang, Qi

2017-10-01

Glass-Fibre-Reinforced Polymer (GFRP), as a developing construction material, has a rapidly increasing application in civil engineering especially bridge engineering area these years, mainly used as decorating materials and reinforcing bars for now. Compared with traditional construction material, these kinds of composite material have obvious advantages such as high strength, low density, resistance to corrosion and ease of processing. There are different processing methods to form members, such as pultrusion and resin transfer moulding (RTM) methods, which process into desired shape directly through raw material; meanwhile, GFRP, as a polymer composite, possesses several particular physical and mechanical properties, and the thermal property is one of them. The matrix material, polymer, performs special after heated and endue these composite material a potential hot processing property, but also a poor fire resistance. This paper focuses on thermal performance of GFRP as panels and corresponding researches are conducted. First, dynamic thermomechanical analysis (DMA) experiment is conducted to obtain the glass transition temperature (Tg) of the object GFRP, and the curve of bending elastic modulus with temperature is calculated according to the experimental data. Then compute and estimate the values of other various thermal parameters through DMA experiment and other literatures, and conduct numerical simulation under two condition respectively: (1) the heat transfer process of GFRP panel in which the panel would be heated directly on the surface above Tg, and the hot processing under this temperature field; (2) physical and mechanical performance of GFRP panel under fire condition. Condition (1) is mainly used to guide the development of high temperature processing equipment, and condition (2) indicates that GFRP’s performance under fire is unsatisfactory, measures must be taken when being adopted. Since composite materials’ properties differ from each other and their high temperature parameters can’t be obtained through common methods, some parameters are estimated, the simulation is to guide the actual high temperature experiment, and the parameters will also be adjusted by then.

Development of Laser Fabricated Ti-6Al-4V

NASA Technical Reports Server (NTRS)

deGroh, Henry C., III

2006-01-01

Laser Engineered Net Shaping (LENS) depositions with Ti-6Al-4V gas-atomized powder were accomplished at five different temperatures, ranging from 30 to 400 C, imposed on the base plate. These base plate temperatures were employed in an effort to relieve stresses which develop during the deposition. Warpage of the base plate was monitored. Only a slight decline in warpage was observed as the base plate temperature was increased. Results indicate that substrate temperatures closer to the stress relief minimum of 480 C would relieve deposition stresses, though process parameters would likely need to be modified to compensate for the higher base plate temperature. The compositions of the as-received powder and the LENS deposited material were chemically analyzed. The oxygen content of the LENS material was 0.154 wt.% which is less than the maximum impurity limit of 0.2 percent for commercial Ti-6Al-4V alloys, but is over the limit allowed in ELI grade (0.13 percent). The level of oxygen in the commercial base plate used was only 0.0635 percent. Tensile specimens were machined from the LENS deposited material and tested in tension at room temperature. The ultimate and yield tensile stresses of the LENS material were about 1200 and 1150 MPa respectively, which is about 20 percent higher than the strengths of wrought Ti-6Al-4V. The higher strength of the LENS material was due to its fine structure and high oxygen content. The LENS deposits were not fully dense; voids were frequent at the interfaces between deposited layers. These dispersed sheets of voids were parallel to the longitudinal axis of the resulting tensile specimens. Apparently there was sufficient continuous, fully dense material longitudinally to enable the high strengths. Ductility was low in the LENS material. Percent elongation at failure in the LENS material was near 4 percent, which is less than half of what is usually expected from Ti-6Al-4V. The low ductility was caused by high oxygen levels, and the presence of voids. It is likely that the relatively high scan speeds used in our depositions contributed to the lack of full density in our LENS material.

Temperature-feedback upconversion nanocomposite for accurate photothermal therapy at facile temperature

PubMed Central

Zhu, Xingjun; Feng, Wei; Chang, Jian; Tan, Yan-Wen; Li, Jiachang; Chen, Min; Sun, Yun; Li, Fuyou

2016-01-01

Photothermal therapy (PTT) at present, following the temperature definition for conventional thermal therapy, usually keeps the temperature of lesions at 42–45 °C or even higher. Such high temperature kills cancer cells but also increases the damage of normal tissues near lesions through heat conduction and thus brings about more side effects and inhibits therapeutic accuracy. Here we use temperature-feedback upconversion nanoparticle combined with photothermal material for real-time monitoring of microscopic temperature in PTT. We observe that microscopic temperature of photothermal material upon illumination is high enough to kill cancer cells when the temperature of lesions is still low enough to prevent damage to normal tissue. On the basis of the above phenomenon, we further realize high spatial resolution photothermal ablation of labelled tumour with minimal damage to normal tissues in vivo. Our work points to a method for investigating photothermal properties at nanoscale, and for the development of new generation of PTT strategy. PMID:26842674

Temperature-feedback upconversion nanocomposite for accurate photothermal therapy at facile temperature.

PubMed

Zhu, Xingjun; Feng, Wei; Chang, Jian; Tan, Yan-Wen; Li, Jiachang; Chen, Min; Sun, Yun; Li, Fuyou

2016-02-04

Photothermal therapy (PTT) at present, following the temperature definition for conventional thermal therapy, usually keeps the temperature of lesions at 42-45 °C or even higher. Such high temperature kills cancer cells but also increases the damage of normal tissues near lesions through heat conduction and thus brings about more side effects and inhibits therapeutic accuracy. Here we use temperature-feedback upconversion nanoparticle combined with photothermal material for real-time monitoring of microscopic temperature in PTT. We observe that microscopic temperature of photothermal material upon illumination is high enough to kill cancer cells when the temperature of lesions is still low enough to prevent damage to normal tissue. On the basis of the above phenomenon, we further realize high spatial resolution photothermal ablation of labelled tumour with minimal damage to normal tissues in vivo. Our work points to a method for investigating photothermal properties at nanoscale, and for the development of new generation of PTT strategy.

Tungsten-reinforced tantalum

NASA Technical Reports Server (NTRS)

Bacigalupi, R. J.; Breitwieser, R.

1972-01-01

Method is described for producing tungsten-reinforced tantalum, a material possessing the high temperature strength of tungsten and room temperature ductility and weldability of tantalum. This material is produced by bonding together and overlaying structure of tungsten wires with chemical vapor deposited tantalum.

Durability characterization of ceramic materials for gas turbines

NASA Technical Reports Server (NTRS)

Carruthers, W. D.; Lindberg, L. J.

1987-01-01

The strength retention of ceramic materials during extended high-temperature cyclic exposure is critical to their widespread application in gas turbine engines. During a continuing NASA funded program initated in 1979, reaction bonded silicon nitride (RBSN), sintered silicon carbide (SSC), reaction sintered silicon carbide (RSSC), and sintered silicon nitride (SSN) materials were evaluated following simulated gas turbine engine exposures. Exposures were performed by cycling specimens five times per hour between a high velocity burner discharge and a rapid air quench. The retained flexural strengths were determined following up to 3500 hours of exposure at temperatures up to 1370 C. Post-exposure strengths have been correlated with fractography and surface examination using SEM. Results illustrate excellent strength retention of SSC materials after 3500 hours of exposure to 1370 C. At 1200 C, RBSN and RSSC also demonstrate significant strength retention. Although SSN materials typically suffer significant strength losses during exposures at 1200 C, a new composition, which has improved high-temperature strength, also shows improved durability. In the majority of the materials, strength loss is typically associated with flaw formation in the protective SiO2 layer.

Porous Ceramic Cures at Moderate Temperatures, Is Good Heat Insulator

NASA Technical Reports Server (NTRS)

Eubanks, Alfred G.; Hunkeler, Ronald E.

1965-01-01

The problem: To develop a foamed-in-place refractory material that would provide good thermal insulation, mechanical support, and vibration shielding for enclosed objects at temperatures up to 30000 F. The preparation of conventional foamed refractory materials required long curing times (as much as 48 hours) and high temperatures (at least 700 F), rendering such materials unusable for in-place potting of heat-sensitive components. The solution: A foamed ceramic material that has the requisite thermal insulation and strength, and also displays other properties that suggest a wide range of applications.

High temperature superconductor materials and applications

NASA Technical Reports Server (NTRS)

Doane, George B., III.; Banks, Curtis; Golben, John

1990-01-01

Research on processing methods leading to a significant enhancement in the critical current densities (Jc) and the critical temperature (Tc) of high temperature superconducting in thin bulk and thin film forms. The fabrication of important devices for NASA unique applications (sensors) is investigated.

The high temperature creep behavior of oxides and oxide fibers

NASA Technical Reports Server (NTRS)

Jones, Linda E.; Tressler, Richard E.

1991-01-01

A thorough review of the literature was conducted on the high-temperature creep behavior of single and polycrystalline oxides which potentially could serve as fiber reinforcements in ceramics or metal matrix applications. Sapphire when oriented with the basal plane perpendicular to the fiber axis (c-axis oriented) is highly creep resistant at temperatures in excess of 1600 C and applied loads of 100 MPa and higher. Pyramidal slip is preferentially activated in sapphire under these conditions and steady-state creep rates in the range of 10(exp -7) to 10 (exp -8)/s were reported. Data on the creep resistance of polycrystalline beryllia suggest that C-axiz oriented single crystal beryllia may be a viable candidate as a fiber reinforcement material; however, the issure of fabricability and moisture sensitivity must be addressed for this material. Yttrium aluminum garnet (YAG) also appears to be a fiber candidate material having a high resistance to creep which is due to it's complex crystal structure and high Peierl resistance. The high creep resistance of garnet suggests that there may be other complex ternary oxides such as single crystal mullite which may also be candidate materials for fiber reinforcements. Finally, CVD and single crystal SiC, although not oxides, do possess a high resistance to creep in the temperature range between 1550 and 1850 C and under stresses of 110 to 220 MPa. From a review of the literature, it appears that for high creep resistant applications sapphire, silicon carbide, yttrium aluminum garnet, mullite, and beryllia are desirable candidate materials which require further investigation.

Temperature analysis of laser ignited metalized material using spectroscopic technique

NASA Astrophysics Data System (ADS)

Bassi, Ishaan; Sharma, Pallavi; Daipuriya, Ritu; Singh, Manpreet

2018-05-01

The temperature measurement of the laser ignited aluminized Nano energetic mixture using spectroscopy has a great scope in in analysing the material characteristic and combustion analysis. The spectroscopic analysis helps to do in depth study of combustion of materials which is difficult to do using standard pyrometric methods. Laser ignition was used because it consumes less energy as compared to electric ignition but ignited material dissipate the same energy as dissipated by electric ignition and also with the same impact. Here, the presented research is primarily focused on the temperature analysis of energetic material which comprises of explosive material mixed with nano-material and is ignited with the help of laser. Spectroscopy technique is used here to estimate the temperature during the ignition process. The Nano energetic mixture used in the research does not comprise of any material that is sensitive to high impact.

Evaluation of CVI SiC/SiC Composites for High Temperature Applications

NASA Technical Reports Server (NTRS)

Kiser, D.; Almansour, A.; Smith, C.; Gorican, D.; Phillips, R.; Bhatt, R.; McCue, T.

2017-01-01

Silicon carbide fiber reinforced silicon carbide (SiC/SiC) composites are candidate materials for various high temperature turbine engine applications because of their high specific strength and good creep resistance at temperatures of 1400 C (2552 F) and higher. Chemical vapor infiltration (CVI) SiC/SiC ceramic matrix composites (CMC) incorporating Sylramic-iBN SiC fiber were evaluated via fast fracture tensile tests (acoustic emission damage characterization to assess cracking behavior), tensile creep testing, and microscopy. The results of this testing and observed material behavior degradation mechanisms are reviewed.

High temperature superconductor current leads

DOEpatents

Hull, John R.; Poeppel, Roger B.

1995-01-01

An electrical lead having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths.

High temperature superconductor current leads

DOEpatents

Hull, J.R.; Poeppel, R.B.

1995-06-20

An electrical lead is disclosed having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths. 9 figs.

Process for introducing electrical conductivity into high-temperature polymeric materials

DOEpatents

Liepins, R.; Jorgensen, B.S.; Liepins, L.Z.

1993-12-21

High-temperature electrically conducting polymers are described. The in situ reactions: AgNO[sub 3] + RCHO [yields] Ag + RCOOH and R[sub 3]M [yields] M + 3R, where M=Au or Pt have been found to introduce either substantial bulk or surface conductivity in high-temperature polymers. The reactions involving the R[sub 3]M were caused to proceed thermally suggesting the possibility of using laser means for initiating such reactions in selected areas or volumes of the polymeric materials. The polymers successfully investigated to date are polyphenylquinoxaline, polytolylquinoxaline, polyquinoline, polythiazole, and pyrone.

Processing and Properties Of Refractory Zirconium Diboride Composites For Use In High Temperature Applications

NASA Technical Reports Server (NTRS)

Stackpoole, Margaret; Gusman, M.; Ellerby, D.; Johnson, S. M.; Arnold, Jim (Technical Monitor)

2001-01-01

The Thermal Protection Materials and Systems Branch at NASA Ames Research Center is involved in the development of a class of refractory oxidation-resistant diboride composites termed Ultra High Temperature Ceramics or UHTCs. These composites have good high temperature properties making them candidate materials for thermal protection system (TPS) applications. The current research focuses on improving processing methods to develop more reliable composites with enhanced thermal and mechanical properties. This presentation will concentrate on the processing of ZrB2/SiC composites. Some preliminary mechanical properties and oxidation data will also be presented.

Process for introducing electrical conductivity into high-temperature polymeric materials

DOEpatents

Liepins, Raimond; Jorgensen, Betty S.; Liepins, Leila Z.

1993-01-01

High-temperature electrically conducting polymers. The in situ reactions: AgNO.sub.3 +RCHO.fwdarw.Ag.degree.+RCOOH and R.sub.3 M.fwdarw.M.degree.+3R, where M=Au or Pt have been found to introduce either substantial bulk or surface conductivity in high-temperature polymers. The reactions involving the R.sub.3 M were caused to proceed thermally suggesting the possibility of using laser means for initiating such reactions in selected areas or volumes of the polymeric materials. The polymers successfully investigated to date are polyphenylquinoxaline, polytolylquinoxaline, polyquinoline, polythiazole, and pyrrone.

Process for introducing electrical conductivity into high-temperature polymeric materials

DOEpatents

Liepins, Raimond; Jorgensen, Betty S.; Liepins, Leila Z.

1989-01-01

High-temperature electrically conducting polymers. The in situ reactions: AgNO.sub.3 +RCHO.fwdarw.AG.sup.0 +RCOOH and R.sub.3 M.fwdarw.M.sup.0 3R, where M=Au or Pt have been found to introduce either substantial bulk or surface conductivity in high-temperature polymers. The reactions involving the R.sub.3 M were caused to proceed thermally suggesting the possibility of using laser means for initiating such reactions in selected areas or volumes of the polymeric materials. The polymers successfully investigated to date are polyphenylquinoxaline, polytolylquinoxaline, polyquinoline, polythiazole, and pyrrone.

Process for introducing electrical conductivity into high-temperature polymeric materials

DOEpatents

Liepins, R.; Jorgensen, B.S.; Liepins, L.Z.

1987-08-27

High-temperature electrically conducting polymers. The in situ reactions: AgNO/sub 3/ + RCHO ..-->.. Ag/sup 0/ + RCOOH and R/sub 3/M ..-->.. M/sup 0/ + 3R, where M = Au or Pt have been found to introduce either substantial bulk or surface conductivity in high- temperature polymers. The reactions involving the R/sub 3/M were caused to proceed thermally suggesting the possibility of using laser means for initiating such reactions in selected areas or volumes of the polymeric materials. The polymers successfully investigated to date are polyphenylquinoxaline, polytolylquinoxaline, polyquinoline, polythiazole, and pyrrone. 3 tabs.

Materials for high-temperature thermoelectric conversion

NASA Technical Reports Server (NTRS)

Feigelson, R. S.; Elwell, D.

1983-01-01

High boron materials of high efficiency for thermoelectric power generation and capable of prolonged operation at temperatures over 1200 C are discussed. Background theoretical studies indicated that the low carrier mobility of materials with beta boron and related structures is probably associated with the high density of traps. Experimental work was mainly concerned with silicon borides in view of promising data from European laboratories. A systematic study using structure determination and lattice constant measurements failed to confirm the existence of an SiBn phase. Only SiB6 and a solid solution of silicon in beta boron with a maximum solid solubility of 5.5-6 at % at 1650 C were found.

ASME Material Challenges for Advanced Reactor Concepts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piyush Sabharwall; Ali Siahpush

2013-07-01

This study presents the material Challenges associated with Advanced Reactor Concept (ARC) such as the Advanced High Temperature Reactor (AHTR). ACR are the next generation concepts focusing on power production and providing thermal energy for industrial applications. The efficient transfer of energy for industrial applications depends on the ability to incorporate cost-effective heat exchangers between the nuclear heat transport system and industrial process heat transport system. The heat exchanger required for AHTR is subjected to a unique set of conditions that bring with them several design challenges not encountered in standard heat exchangers. The corrosive molten salts, especially at highermore » temperatures, require materials throughout the system to avoid corrosion, and adverse high-temperature effects such as creep. Given the very high steam generator pressure of the supercritical steam cycle, it is anticipated that water tube and molten salt shell steam generators heat exchanger will be used. In this paper, the ASME Section III and the American Society of Mechanical Engineers (ASME) Section VIII requirements (acceptance criteria) are discussed. Also, the ASME material acceptance criteria (ASME Section II, Part D) for high temperature environment are presented. Finally, lack of ASME acceptance criteria for thermal design and analysis are discussed.« less

Correlative Microscopy of Neutron-Irradiated Materials

DOE PAGES

Briggs, Samuel A.; Sridharan, Kumar; Field, Kevin G.

2016-12-31

A nuclear reactor core is a highly demanding environment that presents several unique challenges for materials performance. Materials in modern light water reactor (LWR) cores must survive several decades in high-temperature (300-350°C) aqueous corrosion conditions while being subject to large amounts of high-energy neutron irradiation. Next-generation reactor designs seek to use more corrosive coolants (e.g., molten salts) and even greater temperatures and neutron doses. The high amounts of disorder and unique crystallographic defects and microchemical segregation effects induced by radiation inevitably lead to property degradation of materials. Thus, maintaining structural integrity and safety margins over the course of the reactor'smore » service life thus necessitates the ability to understand and predict these degradation phenomena in order to develop new, radiation-tolerant materials that can maintain the required performance in these extreme conditions.« less

The global surface temperatures of the Moon as measured by the Diviner Lunar Radiometer Experiment

NASA Astrophysics Data System (ADS)

Williams, J.-P.; Paige, D. A.; Greenhagen, B. T.; Sefton-Nash, E.

2017-02-01

The Diviner Lunar Radiometer Experiment onboard the Lunar Reconnaissance Orbiter (LRO) has been acquiring solar reflectance and mid-infrared radiance measurements nearly continuously since July of 2009. Diviner is providing the most comprehensive view of how regoliths on airless bodies store and exchange thermal energy with the space environment. Approximately a quarter trillion calibrated radiance measurements of the Moon, acquired over 5.5 years by Diviner, have been compiled into a 0.5° resolution global dataset with a 0.25 h local time resolution. Maps generated with this dataset provide a global perspective of the surface energy balance of the Moon and reveal the complex and extreme nature of the lunar surface thermal environment. Our achievable map resolution, both spatially and temporally, will continue to improve with further data acquisition. Daytime maximum temperatures are sensitive to the albedo of the surface and are ∼387-397 K at the equator, dropping to ∼95 K just before sunrise, though anomalously warm areas characterized by high rock abundances can be > 50 K warmer than the zonal average nighttime temperatures. An asymmetry is observed between the morning and afternoon temperatures due to the thermal inertia of the lunar regolith with the dusk terminator ∼30 K warmer than the dawn terminator at the equator. An increase in albedo with incidence angle is required to explain the observed decrease in temperatures with latitude. At incidence angles exceeding ∼40°, topography and surface roughness influence temperatures resulting in increasing scatter in temperatures and anisothermality between Diviner channels. Nighttime temperatures are sensitive to the thermophysical properties of the regolith. High thermal inertia (TI) materials such as large rocks, remain warmer during the long lunar night and result in anomalously warm nighttime temperatures and anisothermality in the Diviner channels. Anomalous maximum and minimum temperatures are highlighted by subtracting the zonal mean temperatures from maps. Terrains can be characterized as low or high reflectance and low or high TI. Low maximum temperatures result from high reflectance surfaces while low minimum temperatures from low-TI material. Conversely, high maximum temperatures result from dark surface, and high minimum temperatures from high-TI materials. Impact craters are found to modify regolith properties over large distances. The thermal signature of Tycho is asymmetric, consistent with an oblique impact coming from the west. Some prominent crater rays are visible in the thermal data and require material with a higher thermal inertial than nominal regolith. The influence of the formation of the Orientale basin on the regolith properties is observable over a substantial portion of the western hemisphere despite its age (∼3.8 Gyr), and may have contributed to mixing of highland and mare material on the southwest margin of Oceanus Procellarum where the gradient in radiative properties at the mare-highland contact is broad (∼200 km).

Optical Method for Detecting Displacements and Strains at Ultra-High Temperatures During Thermo-Mechanical Testing

NASA Technical Reports Server (NTRS)

Roth, Mark C. (Inventor); Smith, Russell W. (Inventor); Sikora, Joseph G. (Inventor); Rivers, H. Kevin (Inventor); Johnston, William M. (Inventor)

2016-01-01

An ultra-high temperature optical method incorporates speckle optics for sensing displacement and strain measurements well above conventional measurement techniques. High temperature pattern materials are used which can endure experimental high temperature environments while simultaneously having a minimum optical aberration. A purge medium is used to reduce or eliminate optical distortions and to reduce, and/or eliminate oxidation of the target specimen.

Processable high temperature resistant polymer matrix materials

NASA Technical Reports Server (NTRS)

Serafini, T. T.

1975-01-01

A review is presented of studies conducted with addition-cured polyimides, giving particular attention to an improved method involving in situ polymerization of monomer reactants (PMR) on the surface of the reinforcing fibers. The studies show that the PMR approach provides a powerful method for fabricating high performance polymer matrix composites. Significant advantages of the PMR approach are related to the superior high temperature properties of the obtained material, lower cost, greater safety, and processing versatility.

Compliant high temperature seals for dissimilar materials

DOEpatents

Rynders, Steven Walton; Minford, Eric; Tressler, Richard Ernest; Taylor, Dale M.

2001-01-01

A high temperature, gas-tight seal is formed by utilizing one or more compliant metallic toroidal ring sealing elements, where the applied pressure serves to activate the seal, thus improving the quality of the seal. The compliant nature of the sealing element compensates for differences in thermal expansion between the materials to be sealed, and is particularly useful in sealing a metallic member and a ceramic tube art elevated temperatures. The performance of the seal may be improved by coating the sealing element with a soft or flowable coating such as silver or gold and/or by backing the sealing element with a bed of fine powder. The material of the sealing element is chosen such that the element responds to stress elastically, even at elevated temperatures, permitting the seal to operate through multiple thermal cycles.

Method for materials deposition by ablation transfer processing

DOEpatents

Weiner, Kurt H.

1996-01-01

A method in which a thin layer of semiconducting, insulating, or metallic material is transferred by ablation from a source substrate, coated uniformly with a thin layer of said material, to a target substrate, where said material is desired, with a pulsed, high intensity, patternable beam of energy. The use of a patternable beam allows area-selective ablation from the source substrate resulting in additive deposition of the material onto the target substrate which may require a very low percentage of the area to be covered. Since material is placed only where it is required, material waste can be minimized by reusing the source substrate for depositions on multiple target substrates. Due to the use of a pulsed, high intensity energy source the target substrate remains at low temperature during the process, and thus low-temperature, low cost transparent glass or plastic can be used as the target substrate. The method can be carried out atmospheric pressures and at room temperatures, thus eliminating vacuum systems normally required in materials deposition processes. This invention has particular application in the flat panel display industry, as well as minimizing materials waste and associated costs.

Nuclear fuel elements and method of making same

DOEpatents

Schweitzer, Donald G.

1992-01-01

A nuclear fuel element for a high temperature gas nuclear reactor that has an average operating temperature in excess of 2000.degree. C., and a method of making such a fuel element. The fuel element is characterized by having fissionable fuel material localized and stabilized within pores of a carbon or graphite member by melting the fissionable material to cause it to chemically react with the carbon walls of the pores. The fissionable fuel material is further stabilized and localized within the pores of the graphite member by providing one or more coatings of pyrolytic carbon or diamond surrounding the porous graphite member so that each layer defines a successive barrier against migration of the fissionable fuel from the pores, and so that the outermost layer of pyrolytic carbon or diamond forms a barrier between the fissionable material and the moderating gases used in an associated high temperature gas reactor. The method of the invention provides for making such new elements either as generally spherically elements, or as flexible filaments, or as other relatively small-sized fuel elements that are particularly suited for use in high temperature gas reactors.

Wide bandgap BaSnO3 films with room temperature conductivity exceeding 104 S cm−1

PubMed Central

Prakash, Abhinav; Xu, Peng; Faghaninia, Alireza; Shukla, Sudhanshu; Ager, Joel W.; Lo, Cynthia S.; Jalan, Bharat

2017-01-01

Wide bandgap perovskite oxides with high room temperature conductivities and structural compatibility with a diverse family of organic/inorganic perovskite materials are of significant interest as transparent conductors and as active components in power electronics. Such materials must also possess high room temperature mobility to minimize power consumption and to enable high-frequency applications. Here, we report n-type BaSnO3 films grown using hybrid molecular beam epitaxy with room temperature conductivity exceeding 104 S cm−1. Significantly, these films show room temperature mobilities up to 120 cm2 V−1 s−1 even at carrier concentrations above 3 × 1020 cm−3 together with a wide bandgap (3 eV). We examine the mobility-limiting scattering mechanisms by calculating temperature-dependent mobility, and Seebeck coefficient using the Boltzmann transport framework and ab-initio calculations. These results place perovskite oxide semiconductors for the first time on par with the highly successful III–N system, thereby bringing all-transparent, high-power oxide electronics operating at room temperature a step closer to reality. PMID:28474675

Wide bandgap BaSnO 3 films with room temperature conductivity exceeding 10 4 S cm -1

DOE PAGES

Prakash, Abhinav; Xu, Peng; Faghaninia, Alireza; ...

2017-05-05

Wide bandgap perovskite oxides with high room temperature conductivities and structural compatibility with a diverse family of organic/inorganic perovskite materials are of sign ificant interest as transparent conductors and as active components in power electronics. Such materials must also possess high room temperature mobility to minimize power consumption and to enable high-frequency applications. Here, we report n-type BaSnO 3 films grown using hybrid molecular beam epitaxy with room temperature conductivity exceeding 10 4 S cm -1 . Significantly, these films show room temperature mobilities up to 120 cm 2 V -1 s -1 even at carrier concentrations abovemore » 3 × 10 20 cm -3 together with a wide bandgap (3 eV). We examine the mobility-limiting scattering mechanisms by calculating temperature-dependent mobility, and Seebeck coefficient using the Boltzmann transport framework and ab-initio calculations. These results place perovskite oxide semiconductors for the first time on par with the highly successful III-N system, thereby bringing all-transparent, high-power oxide electronics operating at room temperature a step closer to reality.« less

High Temperature Piezoelectric Drill

NASA Technical Reports Server (NTRS)

Bao, Xiaoqi; Scott, James; Boudreau, Kate; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom; Zhang, Shujun

2009-01-01

The current NASA Decadal mission planning effort has identified Venus as a significant scientific target for a surface in-situ sampling/analyzing mission. The Venus environment represents several extremes including high temperature (460 deg C), high pressure (9 MPa), and potentially corrosive (condensed sulfuric acid droplets that adhere to surfaces during entry) environments. This technology challenge requires new rock sampling tools for these extreme conditions. Piezoelectric materials can potentially operate over a wide temperature range. Single crystals, like LiNbO3, have a Curie temperature that is higher than 1000 deg C and the piezoelectric ceramics Bismuth Titanate higher than 600 deg C. A study of the feasibility of producing piezoelectric drills that can operate in the temperature range up to 500 deg C was conducted. The study includes the high temperature properties investigations of engineering materials and piezoelectric ceramics with different formulas and doping. The drilling performances of a prototype Ultrasonic/Sonic Drill/Corer (USDC) using high temperate piezoelectric ceramics and single crystal were tested at temperature up to 500 deg C. The detailed results of our study and a discussion of the future work on performance improvements are presented in this paper.

High temperature braided rope seals for static sealing applications

NASA Technical Reports Server (NTRS)

Adams, Michael L.; Olsen, Andrew; Darolia, Ram; Steinetz, Bruce M.; Bartolotta, Paul A.

1996-01-01

Achieving efficiency and performance goals of advanced aircraft and industrial systems are leading designers to implement high temperature materials such as ceramics and intermetallics. Generally these advanced materials are applied selectively in the highest temperature sections of the engine system including the combustor and high pressure turbine, amongst others. Thermal strains that result in attaching the low expansion-rate components to high expansion rate superalloy structures can cause significant life reduction in the components. Seals are being designed to both seal and to serve as compliant mounts allowing for relative thermal growths between high temperature but brittle primary structures and the surrounding support structures. Designers require high temperature, low-leakage, compliant seals to mitigate thermal stresses and control parasitic and cooling airflow between structures. NASA is developing high temperature braided rope seals in a variety of configurations to help solve these problems. This paper will describe the types of seals being developed, describe unique test techniques used to assess seal performance, and present leakage flow data under representative pressure, temperature and scrubbing conditions. Feasibility of the braided rope seals for both an industrial tube seal and a turbine vane seal application is also demonstrated.

Apparatus and method for high temperature viscosity and temperature measurements

DOEpatents

Balasubramaniam, Krishnan; Shah, Vimal; Costley, R. Daniel; Singh, Jagdish P.

2001-01-01

A probe for measuring the viscosity and/or temperature of high temperature liquids, such as molten metals, glass and similar materials comprises a rod which is an acoustical waveguide through which a transducer emits an ultrasonic signal through one end of the probe, and which is reflected from (a) a notch or slit or an interface between two materials of the probe and (b) from the other end of the probe which is in contact with the hot liquid or hot melt, and is detected by the same transducer at the signal emission end. To avoid the harmful effects of introducing a thermally conductive heat sink into the melt, the probe is made of relatively thermally insulative (non-heat-conductive) refractory material. The time between signal emission and reflection, and the amplitude of reflections, are compared against calibration curves to obtain temperature and viscosity values.

Iron Disilicide as High-Temperature Reference Material for Traceable Measurements of Seebeck Coefficient Between 300 K and 800 K

NASA Astrophysics Data System (ADS)

Ziolkowski, Pawel; Stiewe, Christian; de Boor, Johannes; Druschke, Ines; Zabrocki, Knud; Edler, Frank; Haupt, Sebastian; König, Jan; Mueller, Eckhard

2017-01-01

Thermoelectric generators (TEGs) convert heat to electrical energy by means of the Seebeck effect. The Seebeck coefficient is a central thermoelectric material property, measuring the magnitude of the thermovoltage generated in response to a temperature difference across a thermoelectric material. Precise determination of the Seebeck coefficient provides the basis for reliable performance assessment in materials development in the field of thermoelectrics. For several reasons, measurement uncertainties of up to 14% can often be observed in interlaboratory comparisons of temperature-dependent Seebeck coefficient or in error analyses on currently employed instruments. This is still too high for an industrial benchmark and insufficient for many scientific investigations and technological developments. The TESt (thermoelectric standardization) project was launched in 2011, funded by the German Federal Ministry of Education and Research (BMBF), to reduce measurement uncertainties, engineer traceable and precise thermoelectric measurement techniques for materials and TEGs, and develop reference materials (RMs) for temperature-dependent determination of the Seebeck coefficient. We report herein the successful development and qualification of cobalt-doped β-iron disilicide ( β-Fe0.95Co0.05Si2) as a RM for high-temperature thermoelectric metrology. A brief survey on technological processes for manufacturing and machining of samples is presented. Focus is placed on metrological qualification of the iron disilicide, results of an international round-robin test, and final certification as a reference material in accordance with ISO-Guide 35 and the "Guide to the expression of uncertainty in measurement" by the Physikalisch-Technische Bundesanstalt, the national metrology institute of Germany.

Technology development of a biowaste resistojet, volume 1

NASA Technical Reports Server (NTRS)

Phillips, D. G.

1972-01-01

The materials research effort conducted in support of a NASA-sponsored biowaste resistojet development program is summarized. The resistojet concept under development is the concentric tube design wherein the final pass of the gases through the thruster is through the resistance heated center tube. To produce high specific impulses, this center tube must operate at very high temperatures and it is this element that is most critical in the design. Because of the corrosive nature of the biowaste gases at high temperature, and because of the limited data available for many potential materials, the subject materials study was conducted.

Resin Transfer Moldable Polyimides Developed for High-Temperature Applications

NASA Technical Reports Server (NTRS)

Meador, Mary Ann

2000-01-01

High-temperature polyimides, such as PMR 15 (which was developed at the NASA Glenn Research Center at Lewis Field), are becoming an increasingly important class of materials for a variety of aerospace applications, such as aircraft engine components and propulsion and airframe components for reusable launch vehicles (RLV s). Because of their high specific strength and low density, use of these materials in place of more traditional aerospace materials, such as titanium, can significantly reduce component and vehicle weight, leading to reductions in fuel consumption (and pollutants), increases in payload and passenger capacity, and improvements in vehicle performance.

Optical properties of spin-on deposited low temperature titanium oxide thin films

NASA Astrophysics Data System (ADS)

Rantala, J. T.; Kärkkäinen, A. H. O.

2003-06-01

This letter presents a method to fabricate high quality, high refractive index titanium oxide thin films by applying liquid phase spin-on deposition combined with low temperature annealing. The synthesis of the liquid form titanium oxide material is carried out using a sol-gel synthesis technique. The material can be annealed at low temperature (150 C°) to achieve relatively high refractive index of 1.94 at 632.8 nm wavelength, whereas annealing at 350 C° results in index of 2.03 at 632.8 nm. Film depositions are demonstrated on silicon substrates with 0.5% uniformity in thickness. Refractive indices and extinction coefficients are characterized over a broad wavelength range to demonstrate the optical performance of this novel aqueous phase spin-on deposited hybrid titanium oxide material.

Fuel-Cell Electrolytes Based on Organosilica Hybrid Proton Conductors

NASA Technical Reports Server (NTRS)

Narayan, Sri R.; Yen, Shiao-Pin S.

2008-01-01

A new membrane composite material that combines an organosilica proton conductor with perfluorinated Nafion material to achieve good proton conductivity and high-temperature performance for membranes used for fuel cells in stationary, transportation, and portable applications has been developed. To achieve high proton conductivities of the order of 10(exp -1)S/cm over a wide range of temperatures, a composite membrane based on a new class of mesoporous, proton-conducting, hydrogen-bonded organosilica, used with Nafion, will allow for water retention and high proton conductivity over a wider range of temperatures than currently offered by Nafion alone. At the time of this reporting, this innovation is at the concept level. Some of the materials and processes investigated have shown good proton conductivity, but membranes have not yet been prepared and demonstrated.

Thrust chamber life prediction. Volume 1: Mechanical and physical properties of high performance rocket nozzle materials

NASA Technical Reports Server (NTRS)

Esposito, J. J.; Zabora, R. F.

1975-01-01

Pertinent mechanical and physical properties of six high conductivity metals were determined. The metals included Amzirc, NARloy Z, oxygen free pure copper, electroformed copper, fine silver, and electroformed nickel. Selection of these materials was based on their possible use in high performance reusable rocket nozzles. The typical room temperature properties determined for each material included tensile ultimate strength, tensile yield strength, elongation, reduction of area, modulus of elasticity, Poisson's ratio, density, specific heat, thermal conductivity, and coefficient of thermal expansion. Typical static tensile stress-strain curves, cyclic stress-strain curves, and low-cycle fatigue life curves are shown. Properties versus temperature are presented in graphical form for temperatures from 27.6K (-410 F) to 810.9K (1000 F).

Fire-Retardant and Thermally Insulating Phenolic-Silica Aerogels.

PubMed

Yu, Zhi-Long; Yang, Ning; Apostolopoulou-Kalkavoura, Varvara; Qin, Bing; Ma, Zhi-Yuan; Xing, Wei-Yi; Qiao, Chan; Bergström, Lennart; Antonietti, Markus; Yu, Shu-Hong

2018-04-16

Energy efficient buildings require materials with a low thermal conductivity and a high fire resistance. Traditional organic insulation materials are limited by their poor fire resistance and inorganic insulation materials are either brittle or display a high thermal conductivity. Herein we report a mechanically resilient organic/inorganic composite aerogel with a thermal conductivity significantly lower than expanded polystyrene and excellent fire resistance. Co-polymerization and nanoscale phase separation of the phenol-formaldehyde-resin (PFR) and silica generate a binary network with domain sizes below 20 nm. The PFR/SiO 2 aerogel can resist a high-temperature flame without disintegration and prevents the temperature on the non-exposed side from increasing above the temperature critical for the collapse of reinforced concrete structures. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bonded and Sealed External Insulations for Liquid-Hydrogen-Fueled Rocket Tanks During Atmospheric Flight

NASA Technical Reports Server (NTRS)

Gray, V. H.; Gelder, T. F.; Cochran, R. P.; Goodykoontz, J. H.

1960-01-01

Several currently available nonmetallic insulation materials that may be bonded onto liquid-hydrogen tanks and sealed against air penetration into the insulation have been investigated for application to rockets and spacecraft. Experimental data were obtained on the thermal conductivities of various materials in the cryogenic temperature range, as well as on the structural integrity and ablation characteristics of these materials at high temperatures occasioned by aerodynamic heating during atmospheric escape. Of the materials tested, commercial corkboard has the best overall properties for the specific requirements imposed during atmospheric flight of a high-acceleration rocket vehicle.

Temperature-programmed technique accompanied with high-throughput methodology for rapidly searching the optimal operating temperature of MOX gas sensors.

PubMed

Zhang, Guozhu; Xie, Changsheng; Zhang, Shunping; Zhao, Jianwei; Lei, Tao; Zeng, Dawen

2014-09-08

A combinatorial high-throughput temperature-programmed method to obtain the optimal operating temperature (OOT) of gas sensor materials is demonstrated here for the first time. A material library consisting of SnO2, ZnO, WO3, and In2O3 sensor films was fabricated by screen printing. Temperature-dependent conductivity curves were obtained by scanning this gas sensor library from 300 to 700 K in different atmospheres (dry air, formaldehyde, carbon monoxide, nitrogen dioxide, toluene and ammonia), giving the OOT of each sensor formulation as a function of the carrier and analyte gases. A comparative study of the temperature-programmed method and a conventional method showed good agreement in measured OOT.

Superconducting magnetic control system for manipulation of particulate matter and magnetic probes in medical and industrial applications

DOEpatents

Cha, Yung Sheng; Hull, John R.; Askew, Thomas R.

2006-07-11

A system and method of controlling movement of magnetic material with at least first and second high temperature superconductors at spaced locations. A plurality of solenoids are associated with the superconductors to induce a persistent currents in preselected high temperature superconductors establishing a plurality of magnetic fields in response to pulsed currents introduced to one or more of the solenoids. Control mechanism in communication with said solenoids and/or said high temperature superconductors are used to demagnetize selected ones of the high temperature superconductors to reduce the magnetic fields substantially to zero. Magnetic material is moved between magnetic fields by establishing the presence thereof and thereafter reducing magnetic fields substantially to zero and establishing magnetic fields in other superconductors arranged in a predetermined configuration.

Temperature-dependent Refractive Index of Silicon and Germanium

NASA Technical Reports Server (NTRS)

Frey, Bradley J.; Leviton, Douglas B.; Madison, Timothy J.

2006-01-01

Silicon and germanium are perhaps the two most well-understood semiconductor materials in the context of solid state device technologies and more recently micromachining and nanotechnology. Meanwhile, these two materials are also important in the field of infrared lens design. Optical instruments designed for the wavelength range where these two materials are transmissive achieve best performance when cooled to cryogenic temperatures to enhance signal from the scene over instrument background radiation. In order to enable high quality lens designs using silicon and germanium at cryogenic temperatures, we have measured the absolute refractive index of multiple prisms of these two materials using the Cryogenic, High-Accuracy Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center, as a function of both wavelength and temperature. For silicon, we report absolute refractive index and thermo-optic coefficient (dn/dT) at temperatures ranging from 20 to 300 K at wavelengths from 1.1 to 5.6 pin, while for germanium, we cover temperatures ranging from 20 to 300 K and wavelengths from 1.9 to 5.5 microns. We compare our measurements with others in the literature and provide temperature-dependent Sellmeier coefficients based on our data to allow accurate interpolation of index to other wavelengths and temperatures. Citing the wide variety of values for the refractive indices of these two materials found in the literature, we reiterate the importance of measuring the refractive index of a sample from the same batch of raw material from which final optical components are cut when absolute accuracy greater than k5 x 10" is desired.

Coupled Monte Carlo neutronics and thermal hydraulics for power reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernnat, W.; Buck, M.; Mattes, M.

The availability of high performance computing resources enables more and more the use of detailed Monte Carlo models even for full core power reactors. The detailed structure of the core can be described by lattices, modeled by so-called repeated structures e.g. in Monte Carlo codes such as MCNP5 or MCNPX. For cores with mainly uniform material compositions, fuel and moderator temperatures, there is no problem in constructing core models. However, when the material composition and the temperatures vary strongly a huge number of different material cells must be described which complicate the input and in many cases exceed code ormore » memory limits. The second problem arises with the preparation of corresponding temperature dependent cross sections and thermal scattering laws. Only if these problems can be solved, a realistic coupling of Monte Carlo neutronics with an appropriate thermal-hydraulics model is possible. In this paper a method for the treatment of detailed material and temperature distributions in MCNP5 is described based on user-specified internal functions which assign distinct elements of the core cells to material specifications (e.g. water density) and temperatures from a thermal-hydraulics code. The core grid itself can be described with a uniform material specification. The temperature dependency of cross sections and thermal neutron scattering laws is taken into account by interpolation, requiring only a limited number of data sets generated for different temperatures. Applications will be shown for the stationary part of the Purdue PWR benchmark using ATHLET for thermal- hydraulics and for a generic Modular High Temperature reactor using THERMIX for thermal- hydraulics. (authors)« less

MOVPE growth studies of Ga(NAsP)/(BGa)(AsP) multi quantum well heterostructures (MQWH) for the monolithic integration of laser structures on (001) Si-substrates

NASA Astrophysics Data System (ADS)

Ludewig, P.; Reinhard, S.; Jandieri, K.; Wegele, T.; Beyer, A.; Tapfer, L.; Volz, K.; Stolz, W.

2016-03-01

High-quality, pseudomorphically strained Ga(NAsP)/(BGa)(AsP)-multiple quantum well heterostructures (MQWH) have been deposited on exactly oriented (001) Si-substrate by metal organic vapour phase epitaxy (MOVPE) in a wide temperature range between 525 °C and 700 °C. The individual atomic incorporation efficiencies, growth rates as well as nanoscale material properties have been clarified by applying detailed high-resolution X-ray diffraction (HR-XRD), photoluminescence (PL) spectroscopy and high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) studies. An almost constant N-incorporation efficiency is obtained for a wide growth temperature range from 550 °C up to 650 °C. The P-incorporation is steadily increasing with increasing growth temperature reaching values at high temperatures in excess of the applied gas phase ratio. While the lower interface from the binary GaP- to the quaternary Ga(NAsP)-material system is very sharp, the upper interface is significantly rougher with a roughness scale of ±0.43 nm in quantum well thickness variation at a growth temperature of 525 °C. This roughness scale increases steadily with increasing growth temperature. No indication of any phase separation effects is detected in the Ga(NAsP)-material system even at the highest growth temperature of 700 °C. The obtained experimental results are briefly discussed with respect to the anticipated metastable character of the novel dilute-nitride Ga(NAsP)-material system grown lattice-matched to (001) Si-substrate.

Vibrational Properties of Zr(Hf)B2-SiC UHTC Composites by Micro-Raman Spectroscopy

NASA Astrophysics Data System (ADS)

Donohue, M.; Carpenter, C.; Orlovskaya, N.

Development and characterization of novel materials that are lightweight, possess high mechanical properties, can withstand high temperatures, and provide superior thermal properties are crucial to meet the future demands of Air Force, Army, Navy, Missile Defense Agency (MDA), and other military and space agencies. Materials for such applications (hypersonic air-breathing vehicles, including Single-To-Orbit vehicles and Two-Stage-To-Orbit aerospace planes, fully reusable space transport vehicles, hypersonic cruise missiles) experience severe aero-thermal loads with nose-cone and nozzle temperatures in excess of 2,000°F and 4,000°F, respectively. High G acceleration is also a problem. Even the most advanced materials, such as Ti, Inconel X, carbon-carbon, and silicon carbide based composites cannot withstand the excessive heat generated, especially during re-entry, and they cannot meet the guidelines for future high performance aircrafts, kinetic energy interceptors and reusable space planes. Thus, the demand for low-cost, light weight high temperature materials for thermal protection systems (TPS) is expected to be on the significant rise in the near future.

Strong, tough and stiff bioinspired ceramics from brittle constituents

NASA Astrophysics Data System (ADS)

Bouville, Florian; Maire, Eric; Meille, Sylvain; van de Moortèle, Bertrand; Stevenson, Adam J.; Deville, Sylvain

2014-05-01

High strength and high toughness are usually mutually exclusive in engineering materials. In ceramics, improving toughness usually relies on the introduction of a metallic or polymeric ductile phase, but this decreases the material’s strength and stiffness as well as its high-temperature stability. Although natural materials that are both strong and tough rely on a combination of mechanisms operating at different length scales, the relevant structures have been extremely difficult to replicate. Here, we report a bioinspired approach based on widespread ceramic processing techniques for the fabrication of bulk ceramics without a ductile phase and with a unique combination of high strength (470 MPa), high toughness (22 MPa m1/2), and high stiffness (290 GPa). Because only mineral constituents are needed, these ceramics retain their mechanical properties at high temperatures (600 °C). Our bioinspired, material-independent approach should find uses in the design and processing of materials for structural, transportation and energy-related applications.

Mechanical tensile testing of titanium 15-3-3-3 and Kevlar 49 at cryogenic temperatures

NASA Astrophysics Data System (ADS)

James, B. L.; Martinez, R. M.; Shirron, P.; Tuttle, J.; Galassi, N. M.; McGuinness, D. S.; Puckett, D.; Francis, J. J.; Flom, Y.

2012-06-01

Titanium 15-3-3-3 and Kevlar 49 are highly desired materials for structural components in cryogenic applications due to their low thermal conductivity at low temperatures. Previous tests have indicated that titanium 15-3-3-3 becomes increasingly brittle as the temperature decreases. Furthermore, little is known regarding the mechanical properties of Kevlar 49 at low temperatures, most specifically its Young's modulus. This testing investigates the mechanical properties of both materials at cryogenic temperatures through cryogenic mechanical tensile testing to failure. The elongation, ultimate tensile strength, yield strength, and break strength of both materials are provided and analyzed here.

Mechanical Tensile Testing of Titanium 15-3-3-3 and Kevlar 49 at Cryogenic Temperatures

NASA Technical Reports Server (NTRS)

James, Bryan L.; Martinez, Raul M.; Shirron, Peter; Tuttle, Jim; Galassi, Nicholas M.; Mcguinness, Daniel S.; Puckett, David; Francis, John J.; Flom, Yury

2011-01-01

Titanium 15-3-3-3 and Kevlar 49 are highly desired materials for structural components in cryogenic applications due to their low thennal conductivity at low temperatures. Previous tests have indicated that titanium 15-3-3-3 becomes increasingly brittle as the temperature decreases. Furthermore, little is known regarding the mechanical properties of Kevlar 49 at low temperatures, most specifically its Young's modulus. This testing investigates the mechanical properties of both materials at cryogenic temperatures through cryogenic mechanical tensile testing to failure. The elongation, ultimate tensile strength, yield strength, and break strength of both materials are provided and analyzed here.

A Model for Determining Strength for Embedded Elliptical Crack in Ultra-high-temperature Ceramics

PubMed Central

Wang, Ruzhuan; Li, Weiguo

2015-01-01

A fracture strength model applied at room temperature for embedded elliptical crack in brittle solid was obtained. With further research on the effects of various physical mechanisms on material strength, a thermo-damage strength model for ultra-high-temperature ceramics was applied to each temperature phase. Fracture strength of TiC and the changing trends with elliptical crack shape variations under different temperatures were studied. The study showed that under low temperature, the strength is sensitive to the crack shape variation; as the temperature increases, the sensitivities become smaller. The size of ellipse’s minor axes has great effect on the material strength when the ratio of ellipse’s minor and major axes is lower than 0.5, even under relatively high temperatures. The effect of the minor axes of added particle on material properties thus should be considered under this condition. As the crack area is set, the fracture strength decreases firstly and then increases with the increase of ratio of ellipse’s minor and major axes, and the turning point is 0.5. It suggests that for the added particles the ratio of ellipse’s minor and major axes should not be 0.5. All conclusions significantly coincided with the results obtained by using the finite element software ABAQUS. PMID:28793488

A Model for Determining Strength for Embedded Elliptical Crack in Ultra-high-temperature Ceramics.

PubMed

Wang, Ruzhuan; Li, Weiguo

2015-08-05

A fracture strength model applied at room temperature for embedded elliptical crack in brittle solid was obtained. With further research on the effects of various physical mechanisms on material strength, a thermo-damage strength model for ultra-high-temperature ceramics was applied to each temperature phase. Fracture strength of TiC and the changing trends with elliptical crack shape variations under different temperatures were studied. The study showed that under low temperature, the strength is sensitive to the crack shape variation; as the temperature increases, the sensitivities become smaller. The size of ellipse's minor axes has great effect on the material strength when the ratio of ellipse's minor and major axes is lower than 0.5, even under relatively high temperatures. The effect of the minor axes of added particle on material properties thus should be considered under this condition. As the crack area is set, the fracture strength decreases firstly and then increases with the increase of ratio of ellipse's minor and major axes, and the turning point is 0.5. It suggests that for the added particles the ratio of ellipse's minor and major axes should not be 0.5. All conclusions significantly coincided with the results obtained by using the finite element software ABAQUS.

Nb-doped SrTiO3 glass-ceramics as high temperature stable n-type oxide thermoelectrics

NASA Astrophysics Data System (ADS)

Lingner, Julian; Jakob, Gerhard; Letz, Martin

2012-06-01

Niobium doped SrTiO3 is known for its high potential as an oxide thermoelectric material and is one of the possible candidates for the n-type site in an oxidic thermoelectric module. The high thermal conductivity [1] and the lack of high-temperature stability of the oxygen vacancies [2] limit its properties in the ceramic systems. Glass-ceramics are intrinsic nano-structured systems and provide crystal phases densely embedded in a glass matrix which prevents the material from detoriation at high temperatures. In particular, the glass-matrix prevents an uncontrolled reoxidization as well as an uncontrolled grain growth therefore retaining the nano-structure even at high temperatures. Here, measurements and results of first glass-ceramic systems are presented, which show a low thermal conductivity due to the residue glass phase. Furthermore a stable thermal cycling up to 650 °C is demonstrated.

Catalytic thermal barrier coatings

DOEpatents

Kulkarni, Anand A.; Campbell, Christian X.; Subramanian, Ramesh

2009-06-02

A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

Silicon Carbide Nanotube Synthesized

NASA Technical Reports Server (NTRS)

Lienhard, Michael A.; Larkin, David J.

2003-01-01

Carbon nanotubes (CNTs) have generated a great deal of scientific and commercial interest because of the countless envisioned applications that stem from their extraordinary materials properties. Included among these properties are high mechanical strength (tensile and modulus), high thermal conductivity, and electrical properties that make different forms of single-walled CNTs either conducting or semiconducting, and therefore, suitable for making ultraminiature, high-performance CNT-based electronics, sensors, and actuators. Among the limitations for CNTs is their inability to survive in high-temperature, harsh-environment applications. Silicon carbon nanotubes (SiCNTs) are being developed for their superior material properties under such conditions. For example, SiC is stable in regards to oxidation in air to temperatures exceeding 1000 C, whereas carbon-based materials are limited to 600 C. The high-temperature stability of SiCNTs is envisioned to enable high-temperature, harsh-environment nanofiber- and nanotube-reinforced ceramics. In addition, single-crystal SiC-based semiconductors are being developed for hightemperature, high-power electronics, and by analogy to CNTs with silicon semiconductors, SiCNTs with single-crystal SiC-based semiconductors may allow high-temperature harsh-environment nanoelectronics, nanosensors, and nanoactuators to be realized. Another challenge in CNT development is the difficulty of chemically modifying the tube walls, which are composed of chemically stable graphene sheets. The chemical substitution of the CNTs walls will be necessary for nanotube self-assembly and biological- and chemical-sensing applications. SiCNTs are expected to have a different multiple-bilayer wall structure, allowing the surface Si atoms to be functionalized readily with molecules that will allow SiCNTs to undergo self-assembly and be compatible with a variety of materials (for biotechnology applications and high-performance fiber-reinforced ceramics).

High-Power, High-Temperature Superconductor Technology Development

NASA Technical Reports Server (NTRS)

Bhasin, Kul B.

2005-01-01

Since the first discovery of high-temperature superconductors (HTS) 10 years ago, the most promising areas for their applications in microwave systems have been as passive components for communication systems. Soon after the discovery, experiments showed that passive microwave circuits made from HTS material exceeded the performance of conventional devices for low-power applications and could be 10 times as small or smaller. However, for superconducting microwave components, high-power microwave applications have remained elusive until now. In 1996, DuPont and Com Dev Ltd. developed high-power superconducting materials and components for communication applications under a NASA Lewis Research Center cooperative agreement, NCC3-344 "High Power High Temperature Superconductor (HTS) Technology Development." The agreement was cost shared between the Defense Advanced Research Projects Agency's (DARPA) Technology Reinvestment Program Office and the two industrial partners. It has the following objectives: 1) Material development and characterization for high-power HTS applications; 2) Development and validation of generic high-power microwave components; 3) Development of a proof-of-concept model for a high-power six-channel HTS output multiplexer.

Model A: High-Temperature Tribometer

DTIC Science & Technology

1992-02-01

spring loaded collet which grips the pin. In previous machines Inconel 625 collets and sleeves with 450 contact angles were used without collet...Triboeter, high temperature, friction, wear 11 1 08__ 19 ABSTRACT (Continue on revere if necewry and identify by blck number) A high temperature...tribometer has been specifically designed and fabricated to accurately measure, in real time, friction and wear characteristics of materials at temperatures

Nonaqueous Electrical Storage Device

DOEpatents

McEwen, Alan B.; Evans, David A.; Blakley, Thomas J.; Goldman, Jay L.

1999-10-26

An electrochemical capacitor is disclosed that features two, separated, high surface area carbon cloth electrodes sandwiched between two current collectors fabricated of a conductive polymer having a flow temperature greater than 130.degree. C., the perimeter of the electrochemical capacitor being sealed with a high temperature gasket to form a single cell device. The gasket material is a thermoplastic stable at temperatures greater than 100.degree. C., preferably a polyester or a polyurethane, and having a reflow temperature above 130.degree. C. but below the softening temperature of the current collector material. The capacitor packaging has good mechanical integrity over a wide temperature range, contributes little to the device equivalent series resistance (ESR), and is stable at high potentials. In addition, the packaging is designed to be easily manufacturable by assembly line methods. The individual cells can be stacked in parallel or series configuration to reach the desired device voltage and capacitance.

Induction Heating Model of Cermet Fuel Element Environmental Test (CFEET)

NASA Technical Reports Server (NTRS)

Gomez, Carlos F.; Bradley, D. E.; Cavender, D. P.; Mireles, O. R.; Hickman, R. R.; Trent, D.; Stewart, E.

2013-01-01

Deep space missions with large payloads require high specific impulse and relatively high thrust to achieve mission goals in reasonable time frames. Nuclear Thermal Rockets (NTR) are capable of producing a high specific impulse by employing heat produced by a fission reactor to heat and therefore accelerate hydrogen through a rocket nozzle providing thrust. Fuel element temperatures are very high (up to 3000 K) and hydrogen is highly reactive with most materials at high temperatures. Data covering the effects of high-temperature hydrogen exposure on fuel elements are limited. The primary concern is the mechanical failure of fuel elements due to large thermal gradients; therefore, high-melting-point ceramics-metallic matrix composites (cermets) are one of the fuels under consideration as part of the Nuclear Cryogenic Propulsion Stage (NCPS) Advance Exploration System (AES) technology project at the Marshall Space Flight Center. The purpose of testing and analytical modeling is to determine their ability to survive and maintain thermal performance in a prototypical NTR reactor environment of exposure to hydrogen at very high temperatures and obtain data to assess the properties of the non-nuclear support materials. The fission process and the resulting heating performance are well known and do not require that active fissile material to be integrated in this testing. A small-scale test bed; Compact Fuel Element Environmental Tester (CFEET), designed to heat fuel element samples via induction heating and expose samples to hydrogen is being developed at MSFC to assist in optimal material and manufacturing process selection without utilizing fissile material. This paper details the analytical approach to help design and optimize the test bed using COMSOL Multiphysics for predicting thermal gradients induced by electromagnetic heating (Induction heating) and Thermal Desktop for radiation calculations.

High temperature thruster technology for spacecraft propulsion

NASA Technical Reports Server (NTRS)

Schneider, Steven J.

1991-01-01

A technology program intended to develop high-temperature oxidation-resistant thrusters for spacecraft applications is considered. The program will provide the requisite material characterizations and fabrication to incorporate iridium coated rhenium material into small rockets for spacecraft propulsion. This material increases the operating temperature of thrusters to 2200 C, a significant increase over the 1400 C of the silicide-coated niobium chambers currently used. Stationkeeping class 22 N engines fabricated from iridium-coated rhenium have demonstrated steady state specific impulses 20-25 seconds higher than niobium chambers. These improved performances are obtained by reducing or eliminating the fuel film cooling requirements in the combustion chamber while operating at the same overall mixture ratio as conventional engines.

Time dependent reliability model incorporating continuum damage mechanics for high-temperature ceramics

NASA Technical Reports Server (NTRS)

Duffy, Stephen F.; Gyekenyesi, John P.

1989-01-01

Presently there are many opportunities for the application of ceramic materials at elevated temperatures. In the near future ceramic materials are expected to supplant high temperature metal alloys in a number of applications. It thus becomes essential to develop a capability to predict the time-dependent response of these materials. The creep rupture phenomenon is discussed, and a time-dependent reliability model is outlined that integrates continuum damage mechanics principles and Weibull analysis. Several features of the model are presented in a qualitative fashion, including predictions of both reliability and hazard rate. In addition, a comparison of the continuum and the microstructural kinetic equations highlights a strong resemblance in the two approaches.

High Resolution Thermometry for EXACT

NASA Technical Reports Server (NTRS)

Panek, J. S.; Nash, A. E.; Larson, M.; Mulders, N.

2000-01-01

High Resolution Thermometers (HRTs) based on SQUID detection of the magnetization of a paramagnetic salt or a metal alloy has been commonly used for sub-nano Kelvin temperature resolution in low temperature physics experiments. The main applications to date have been for temperature ranges near the lambda point of He-4 (2.177 K). These thermometers made use of materials such as Cu(NH4)2Br4 *2H2O, GdCl3, or PdFe. None of these materials are suitable for EXACT, which will explore the region of the He-3/He-4 tricritical point at 0.87 K. The experiment requirements and properties of several candidate paramagnetic materials will be presented, as well as preliminary test results.

Design of HTS filter for GSM-R communication system

NASA Astrophysics Data System (ADS)

Cui, Hongyu; Ji, Laiyun

2018-04-01

High-temperature superconducting materials with its excellent performance have increasingly been valued by industries, especially in the field of electronic information. The superconducting material has almost zero surface resistance, and the filter made of it has the characteristics of low insertion loss, high edge steepness and good out-of-band rejection. It has higher selectivity for the desired signal and thus less interference from adjacent channels Signal interference, and noise reduction coefficient can improve the ability to detect weak signals. This design is suitable for high temperature superconducting filter of GSM-R communication system, which can overcome many shortcomings of the traditional GSM-R. The filter is made of DyBCO, a high temperature superconducting thin film material based on magnesium oxide (MgO) substrate with the dielectric constant of 9.7, the center frequency at 887.5MHz, bandwidth of 5MHz.

High-Temperature Graphite/Phenolic Composite

NASA Technical Reports Server (NTRS)

Seal, Ellis C.; Bodepudi, Venu P.; Biggs, Robert W., Jr.; Cranston, John A.

1995-01-01

Graphite-fiber/phenolic-resin composite material retains relatively high strength and modulus of elasticity at temperatures as high as 1,000 degrees F. Costs only 5 to 20 percent as much as refractory materials. Fabrication composite includes curing process in which application of full autoclave pressure delayed until after phenolic resin gels. Curing process allows moisture to escape, so when composite subsequently heated in service, much less expansion of absorbed moisture and much less tendency toward delamination. Developed for nose cone of external fuel tank of Space Shuttle. Other potential aerospace applications for material include leading edges, parts of nozzles, parts of aircraft engines, and heat shields. Terrestrial and aerospace applications include structural firewalls and secondary structures in aircraft, spacecraft, and ships. Modified curing process adapted to composites of phenolic with other fiber reinforcements like glass or quartz. Useful as high-temperature circuit boards and electrical insulators.

Strength of "Light" Ferritic and Austenitic Steels Based on the Fe - Mn - Al - C System

NASA Astrophysics Data System (ADS)

Kaputkina, L. M.; Svyazhin, A. G.; Smarygina, I. V.; Kindop, V. E.

2017-01-01

The phase composition, the hardness, the mechanical properties at room temperature, and the resistance to hot (950 - 1000°C) and warm (550°C) deformation are studied for cast deformable "light" ferritic and austenitic steels of the Fe - (12 - 25)% Mn - (0 - 15)% Al - (0 - 2)% C system alloyed additionally with about 5% Ni. The high-aluminum high-manganese low-carbon and carbonless ferritic steels at a temperature of about 0.5 T melt have a specific strength close to that of the austenitic steels and may be used as weldable scale-resistant and wear-resistant materials. The high-carbon Fe - (20 - 24)% Mn - (5 - 9)% Al - 5% Ni - 1.5% C austenitic steels may be applied as light high-strength materials operating at cryogenic temperatures after a solution treatment and as scale- and heat-resistant materials in an aged condition.

PMR Extended Shelf Life Technology Given 2000 R and D 100 Award

NASA Technical Reports Server (NTRS)

Meador, Michael A.

2001-01-01

An approach developed at the NASA Glenn Research Center for extending the shelf life of PMR polyimide solutions and prepregs received an R&D 100 Award this year. PMR polyimides, in particular PMR-15, have become attractive materials for a variety of aerospace applications because of their outstanding high-temperature stability and performance. PMR-15 can be used in components with exposures to temperatures as high as 290 C, which leads to substantial reductions in weight, as much as 30 percent over metal components. PMR-15 composites are used widely in aerospace applications ranging from ducts and external components in aircraft engines to an engine access door for the Space Shuttle Main Engine. A major barrier to more widespread use of these materials is high component costs. Recent efforts at Glenn have addressed the various factors that contribute to these costs in an attempt to more fully utilize these lightweight, high-temperature materials.

High-efficiency machining methods for aviation materials

NASA Astrophysics Data System (ADS)

Kononov, V. K.

1991-07-01

The papers contained in this volume present results of theoretical and experimental studies aimed at increasing the efficiency of cutting tools during the machining of high-temperature materials and titanium alloys. Specific topics discussed include a study of the performance of disk cutters during the machining of flexible parts of a high-temperature alloy, VZhL14N; a study of the wear resistance of cutters of hard alloys of various types; effect of a deformed electric field on the precision of the electrochemical machining of gas turbine engine components; and efficient machining of parts of composite materials. The discussion also covers the effect of the technological process structure on the residual stress distribution in the blades of gas turbine engines; modeling of the multiparameter assembly of engineering products for a specified priority of geometrical output parameters; and a study of the quality of the surface and surface layer of specimens machined by a high-temperature pulsed plasma.

Potential High-Temperature Shape-Memory-Alloy Actuator Material Identified

NASA Technical Reports Server (NTRS)

Noebe, Ronald D.; Gaydosh, Darrell J.; Biles, Tiffany A.; Garg, Anita

2005-01-01

Shape-memory alloys are unique "smart materials" that can be used in a wide variety of adaptive or "intelligent" components. Because of a martensitic solid-state phase transformation in these materials, they can display rather unusual mechanical properties including shape-memory behavior. This phenomenon occurs when the material is deformed at low temperatures (below the martensite finish temperature, Mf) and then heated through the martensite-to-austenite phase transformation. As the material is heated to the austenite finish temperature Af, it is able to recover its predeformed shape. If a bias is applied to the material as it tries to recover its original shape, work can be extracted from the shape-memory alloy as it transforms. Therefore, shape-memory alloys are being considered for compact solid-state actuation devices to replace hydraulic, pneumatic, or motor-driven systems.

High temperature arc-track resistant aerospace insulation

NASA Technical Reports Server (NTRS)

Dorogy, William

1994-01-01

The topics are presented in viewgraph form and include the following: high temperature aerospace insulation; Foster-Miller approach to develop a 300 C rated, arc-track resistant aerospace insulation; advantages and disadvantages of key structural features; summary goals and achievements of the phase 1 program; performance goals for selected materials; materials under evaluation; molecular structures of candidate polymers; candidate polymer properties; film properties; and a detailed program plan.

The total hemispheric emissivity of painted aluminum honeycomb at cryogenic temperatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tuttle, J.; Canavan, E.; DiPirro, M.

NASA uses high-emissivity surfaces on deep-space radiators and thermal radiation absorbers in test chambers. Aluminum honeycomb core material, when coated with a high-emissivity paint, provides a lightweight, mechanically robust, and relatively inexpensive black surface that retains its high emissivity down to low temperatures. At temperatures below about 100 Kelvin, this material performs much better than the paint itself. We measured the total hemispheric emissivity of various painted honeycomb configurations using an adaptation of an innovative technique developed for characterizing thin black coatings. These measurements were performed from room temperature down to 30 Kelvin. We describe the measurement technique and comparemore » the results with predictions from a detailed thermal model of each honeycomb configuration.« less

Polymorphism in a high-entropy alloy

DOE PAGES

Zhang, Fei; Wu, Yuan; Lou, Hongbo; ...

2017-06-01

Polymorphism, which describes the occurrence of different lattice structures in a crystalline material, is a critical phenomenon in materials science and condensed matter physics. Recently, configuration disorder was compositionally engineered into single lattices, leading to the discovery of high-entropy alloys and high-entropy oxides. For these novel entropy-stabilized forms of crystalline matter with extremely high structural stability, is polymorphism still possible? Here by employing in situ high-pressure synchrotron radiation X-ray diffraction, we reveal a polymorphic transition from face-centred-cubic (fcc) structure to hexagonal-close-packing (hcp) structure in the prototype CoCrFeMnNi high-entropy alloy. The transition is irreversible, and our in situ high-temperature synchrotron radiationmore » X-ray diffraction experiments at different pressures of the retained hcp high-entropy alloy reveal that the fcc phase is a stable polymorph at high temperatures, while the hcp structure is more thermodynamically favourable at lower temperatures. Lastly, as pressure is increased, the critical temperature for the hcp-to-fcc transformation also rises.« less

Advanced Capacitor with SiC for High Temperature Applications

NASA Astrophysics Data System (ADS)

Tsao, B. H.; Ramalingam, M. L.; Bhattacharya, R. S.; Carr, Sandra Fries

1994-07-01

An advanced capacitor using SiC as the dielectric material has been developed for high temperature, high power, and high density electronic components for aircraft and aerospace application. The conventional capacitor consists of a large number of metallized polysulfone films that are arranged in parallel and enclosed in a sealed metal case. However, problems with electrical failure, thermal failure, and dielectric flow were experienced by Air Force suppliers for the component and subsystem for lack of suitable properties of the dielectric material. The high breakdown electrical field, high thermal conductivity, and high temperature operational resistance of SiC compared to similar properties of the conventional ceramic and polymer capacitor would make it a better choice for a high temperature, and high power capacitor. The quality of the SiC film was evaluated. The electrical parameters, such as the capacitance, dissipation factor, equivalent series resistance, and dielectric withstand voltage, were evaluated. The prototypical capacitors are currently being fabricated using SiC film.

Ultra-high temperature isothermal furnace liners (IFLS) for copper freeze point cells

NASA Astrophysics Data System (ADS)

Dussinger, P. M.; Tavener, J. P.

2013-09-01

Primary Laboratories use large fixed-point cells in deep calibration furnaces utilizing heat pipes to achieve temperature uniformity. This combination of furnace, heat pipe, and cell gives the smallest of uncertainties. The heat pipe, also known as an isothermal furnace liner (IFL), has typically been manufactured with Alloy 600/601 as the envelope material since the introduction of high temperature IFLs over 40 years ago. Alloy 600/601 is a widely available high temperature material, which is compatible with Cesium, Potassium, and Sodium and has adequate oxidation resistance and reasonable high temperature strength. Advanced Cooling Technologies, Inc. (ACT) Alloy 600/Sodium IFLs are rated to 1100°C for approximately 1000 hours of operation (based on creep strength). Laboratories interested in performing calibrations and studies around the copper freezing point (1084.62°C) were frustrated by the 1000 hours at 1100°C limitation and the fact that expensive freeze-point cells were getting stuck and/or crushed inside the IFL. Because of this growing frustration/need, ACT developed an Ultra High Temperature IFL to take advantage of the exceptional high temperature strength properties of Haynes 230.

Molecular Weight Effects on the Viscoelastic Response of a Polyimide

NASA Technical Reports Server (NTRS)

Nicholson, Lee M.; Whitley, Karen S.; Gates, Thomas S.

2000-01-01

The effect of molecular weight on the viscoelastic performance of an advanced polymer (LaRC -SI) was investigated through the use of creep compliance tests. Testing consisted of short-term isothermal creep and recovery with the creep segments performed under constant load. The tests were conducted at three temperatures below the glass transition temperature of each material with different molecular weight. Through the use of time-aging-time superposition procedures, the material constants, material master curves and aging-related parameters were evaluated at each temperature for a given molecular weight. The time-temperature superposition technique helped to describe the effect of temperature on the timescale of the viscoelastic response of each molecular weight. It was shown that the low molecular weight materials have increased creep compliance and creep compliance rate, and are more sensitive to temperature than the high molecular weight materials. Furthermore, a critical molecular weight transition was observed to occur at a weight-average molecular weight of approximately 25000 g/mol below which, the temperature sensitivity of the time-temperature superposition shift factor increases rapidly.

High Electron Mobility and Disorder Induced by Silver Ion Migration Lead to Good Thermoelectric Performance in the Argyrodite Ag 8 SiSe 6

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heep, Barbara K.; Weldert, Kai S.; Krysiak, Yasar

Superionic chalcopyrites have recently attracted interest in their use as potential thermoelectric materials because of extraordinary low thermal conductivities. To overcome long-term stability issues in thermoelectric generators using superionic materials at evaluated temperatures, materials need to be found that show good thermoelectric performance at moderate temperatures. Here, we present the structural and thermoelectric properties of the argyrodite Ag 8SiSe 6, which exhibits promising thermoelectric performance close to room temperature.

Thermal Expansion and Thermal Conductivity of Rare Earth Silicates

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Lee, Kang N.; Bansal, Narottam P.

2006-01-01

Rare earth silicates are considered promising candidate materials for environmental barrier coatings applications at elevated temperature for ceramic matrix composites. High temperature thermophysical properties are of great importance for coating system design and development. In this study, the thermal expansion and thermal conductivity of hot-pressed rare earth silicate materials were characterized at temperatures up to 1400 C. The effects of specimen porosity, composition and microstructure on the properties were also investigated. The materials processing and testing issues affecting the measurements will also be discussed.

High temperature deformation of NiAl and CoAl

NASA Technical Reports Server (NTRS)

Nix, W. D.

1982-01-01

The high temperature mechanical properties of the aluminides are reviewed with respect to their potential as high temperature structural materials. It is shown that NiAl and CoAl are substantially stronger than the pure metals Ni and Co at high temperatures and approach the strength of some superalloys, particularly when those superalloys are tested in "weak" directions. The factors that limit and control the high temperature strengths of NiAl and CoAl are examined to provide a basis for the development of intermetallic alloys of this type.

A high-temperature superconducting transformer with localized magnetic field

NASA Astrophysics Data System (ADS)

Volkov, E. P.; Dzhafarov, E. A.

2013-12-01

This paper describes a high-temperature superconducting transformer with a bar-type magnetic core and concentric windings with alternating layers, with single-channel and multi-channel arrangements. There is given the design concept of high-temperature superconducting windings of the transformer, made in the form of newly developed first-generation high-temperature superconducting ribbon wires, with localized magnetic field intended for producing maximum transport currents in the windings, as well as for reducing the consumption of a high-temperature superconducting material, cooling agent, and energy losses in these windings.

Crystal Lattice Controlled SiGe Thermoelectric Materials with High Figure of Merit

NASA Technical Reports Server (NTRS)

Kim, Hyun-Jung; Park, Yeonjoon; King, Glen C.; Lee, Kunik; Choi, Sang H.

2010-01-01

Direct energy conversion between thermal and electrical energy, based on thermoelectric (TE) effect, has the potential to recover waste heat and convert it to provide clean electric power. The energy conversion efficiency is related to the thermoelectric figure of merit ZT expressed as ZT=S(exp 2)(sigma)T/Kappa, T is temperature, S is the Seebeck coefficient, sigma is conductance and Kappa is thermal conductivity. For a lower thermal conductivity Kappa and high power factor (S(exp 2)(sigma)), our current strategy is the development of rhombohedrally strained single crystalline SiGe materials that are highly [111]-oriented twinned. The development of a SiGe "twin lattice structure (TLS)" plays a key role in phonon scattering. The TLS increases the electrical conductivity and decreases thermal conductivity due to phonon scattering at stacking faults generated from the 60 X rotated primary twin structure. To develop high performance materials, the substrate temperature, chamber working pressure, and DC sputtering power are controlled for the aligned growth production of SiGe layer and TLS on a c-plane sapphire. Additionally, a new elevated temperature thermoelectric characterization system, that measures the thermal diffusivity and Seebeck effect nondestructively, was developed. The material properties were characterized at various temperatures and optimized process conditions were experimentally determined. The present paper encompasses the technical discussions toward the development of thermoelectric materials and the measurement techniques.

Physical Conditions in Shocked Interstellar Gas Interacting with the Supernova Remnant IC 443

NASA Astrophysics Data System (ADS)

Ritchey, Adam M.; Federman, Steven Robert; Jenkins, Edward B.; Caprioli, Damiano; Wallerstein, George

2018-06-01

We present the results of a detailed investigation into the physical conditions in interstellar material interacting with the supernova remnant IC 443. Our analysis is based on an examination of high-resolution HST/STIS spectra of two stars probing predominantly neutral gas located both ahead of and behind the supernova shock front. The pre-shock neutral gas is characterized by densities and temperatures typical of diffuse interstellar clouds, while the post-shock material exhibits a range of more extreme physical conditions, including high temperatures (>104 K) in some cases, which may require a sudden heating event to explain. The ionization level is enhanced in the high-temperature post-shock material, which could be the result of enhanced radiation from shocks or from an increase in cosmic-ray ionization. The gas-phase abundances of refractory elements are also enhanced in the high-pressure gas, suggesting efficient destruction of dust grains by shock sputtering. Observations of highly-ionized species at very high velocity indicate a post-shock temperature of 107 K for the hot X-ray emitting plasma of the remnant’s interior, in agreement with studies of thermal X-ray emission from IC 443.

Development of next generation tempered and ODS reduced activation ferritic/martensitic steels for fusion energy applications

DOE PAGES

Zinkle, S. J.; Boutard, J. L.; Hoelzer, D. T.; ...

2017-06-09

Reduced activation ferritic/martensitic steels are currently the most technologically mature option for the structural material of proposed fusion energy reactors. Advanced next-generation higher performance steels offer the opportunity for improvements in fusion reactor operational lifetime and reliability, superior neutron radiation damage resistance, higher thermodynamic efficiency, and reduced construction costs. The two main strategies for developing improved steels for fusion energy applications are based on (1) an evolutionary pathway using computational thermodynamics modelling and modified thermomechanical treatments (TMT) to produce higher performance reduced activation ferritic/martensitic (RAFM) steels and (2) a higher risk, potentially higher payoff approach based on powder metallurgy techniquesmore » to produce very high strength oxide dispersion strengthened (ODS) steels capable of operation to very high temperatures and with potentially very high resistance to fusion neutron-induced property degradation. The current development status of these next-generation high performance steels is summarized, and research and development challenges for the successful development of these materials are outlined. In conclusion, material properties including temperature-dependent uniaxial yield strengths, tensile elongations, high-temperature thermal creep, Charpy impact ductile to brittle transient temperature (DBTT) and fracture toughness behaviour, and neutron irradiation-induced low-temperature hardening and embrittlement and intermediate-temperature volumetric void swelling (including effects associated with fusion-relevant helium and hydrogen generation) are described for research heats of the new steels.« less

Development of next generation tempered and ODS reduced activation ferritic/martensitic steels for fusion energy applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zinkle, S. J.; Boutard, J. L.; Hoelzer, D. T.

Reduced activation ferritic/martensitic steels are currently the most technologically mature option for the structural material of proposed fusion energy reactors. Advanced next-generation higher performance steels offer the opportunity for improvements in fusion reactor operational lifetime and reliability, superior neutron radiation damage resistance, higher thermodynamic efficiency, and reduced construction costs. The two main strategies for developing improved steels for fusion energy applications are based on (1) an evolutionary pathway using computational thermodynamics modelling and modified thermomechanical treatments (TMT) to produce higher performance reduced activation ferritic/martensitic (RAFM) steels and (2) a higher risk, potentially higher payoff approach based on powder metallurgy techniquesmore » to produce very high strength oxide dispersion strengthened (ODS) steels capable of operation to very high temperatures and with potentially very high resistance to fusion neutron-induced property degradation. The current development status of these next-generation high performance steels is summarized, and research and development challenges for the successful development of these materials are outlined. In conclusion, material properties including temperature-dependent uniaxial yield strengths, tensile elongations, high-temperature thermal creep, Charpy impact ductile to brittle transient temperature (DBTT) and fracture toughness behaviour, and neutron irradiation-induced low-temperature hardening and embrittlement and intermediate-temperature volumetric void swelling (including effects associated with fusion-relevant helium and hydrogen generation) are described for research heats of the new steels.« less

Development of next generation tempered and ODS reduced activation ferritic/martensitic steels for fusion energy applications

NASA Astrophysics Data System (ADS)

Zinkle, S. J.; Boutard, J. L.; Hoelzer, D. T.; Kimura, A.; Lindau, R.; Odette, G. R.; Rieth, M.; Tan, L.; Tanigawa, H.

2017-09-01

Reduced activation ferritic/martensitic steels are currently the most technologically mature option for the structural material of proposed fusion energy reactors. Advanced next-generation higher performance steels offer the opportunity for improvements in fusion reactor operational lifetime and reliability, superior neutron radiation damage resistance, higher thermodynamic efficiency, and reduced construction costs. The two main strategies for developing improved steels for fusion energy applications are based on (1) an evolutionary pathway using computational thermodynamics modelling and modified thermomechanical treatments (TMT) to produce higher performance reduced activation ferritic/martensitic (RAFM) steels and (2) a higher risk, potentially higher payoff approach based on powder metallurgy techniques to produce very high strength oxide dispersion strengthened (ODS) steels capable of operation to very high temperatures and with potentially very high resistance to fusion neutron-induced property degradation. The current development status of these next-generation high performance steels is summarized, and research and development challenges for the successful development of these materials are outlined. Material properties including temperature-dependent uniaxial yield strengths, tensile elongations, high-temperature thermal creep, Charpy impact ductile to brittle transient temperature (DBTT) and fracture toughness behaviour, and neutron irradiation-induced low-temperature hardening and embrittlement and intermediate-temperature volumetric void swelling (including effects associated with fusion-relevant helium and hydrogen generation) are described for research heats of the new steels.

Thermal insulating conformal blanket

NASA Technical Reports Server (NTRS)

Barney, Andrea (Inventor); Whittington, Charles A (Inventor); Eilertson, Bryan (Inventor); Siminski, Zenon (Inventor)

2003-01-01

The conformal thermal insulating blanket may have generally rigid batting material covered by an outer insulating layer formed of a high temperature resistant woven ceramic material and an inner insulating layer formed of a woven ceramic fiber material. The batting and insulating layers may be fastened together by sewing or stitching using an outer mold layer thread fabricated of a high temperature resistant material and an inner mold layer thread of a ceramic fiber material. The batting may be formed to a composite structure that may have a firmness factor sufficient to inhibit a pillowing effect after the stitching to not more than 0.03 inch. The outer insulating layer and an upper portion of the batting adjacent the outer insulating layer may be impregnated with a ceramic coating material.

Achieving ultra-high temperatures with a resistive emitter array

NASA Astrophysics Data System (ADS)

Danielson, Tom; Franks, Greg; Holmes, Nicholas; LaVeigne, Joe; Matis, Greg; McHugh, Steve; Norton, Dennis; Vengel, Tony; Lannon, John; Goodwin, Scott

2016-05-01

The rapid development of very-large format infrared detector arrays has challenged the IR scene projector community to also develop larger-format infrared emitter arrays to support the testing of systems incorporating these detectors. In addition to larger formats, many scene projector users require much higher simulated temperatures than can be generated with current technology in order to fully evaluate the performance of their systems and associated processing algorithms. Under the Ultra High Temperature (UHT) development program, Santa Barbara Infrared Inc. (SBIR) is developing a new infrared scene projector architecture capable of producing both very large format (>1024 x 1024) resistive emitter arrays and improved emitter pixel technology capable of simulating very high apparent temperatures. During earlier phases of the program, SBIR demonstrated materials with MWIR apparent temperatures in excess of 1400 K. New emitter materials have subsequently been selected to produce pixels that achieve even higher apparent temperatures. Test results from pixels fabricated using the new material set will be presented and discussed. A 'scalable' Read In Integrated Circuit (RIIC) is also being developed under the same UHT program to drive the high temperature pixels. This RIIC will utilize through-silicon via (TSV) and Quilt Packaging (QP) technologies to allow seamless tiling of multiple chips to fabricate very large arrays, and thus overcome the yield limitations inherent in large-scale integrated circuits. Results of design verification testing of the completed RIIC will be presented and discussed.

Strain-cycling fatigue behavior of ten structural metals tested in liquid helium (4 K), in liquid nitrogen (78 K), and in ambient air (300 K)

NASA Technical Reports Server (NTRS)

Nachtigall, A. J.

1974-01-01

Strain-cycling fatigue behavior of 10 different structural alloys and metals was investigated in liquid helium (4 K), in liquid nitrogen (78 K), and in ambient air (300 K). At high cyclic lives, fatigue resistance increased with decreasing temperature for all the materials investigated. At low cyclic lives, fatigue resistance generally decreased with decreasing temperature for the materials investigated. Only for Inconel 718 did fatigue resistance increase with decreasing temperature over the entire life range investigated. Comparison of the experimental fatigue behavior with that predicted by the Manson method of universal slopes showed that the fatigue behavior of these materials can be predicted for cryogenic temperatures by using material tensile properties obtained at those same temperatures.

Evaluation of high temperature capacitor dielectrics

NASA Astrophysics Data System (ADS)

Hammoud, Ahmad N.; Myers, Ira T.

Experiments were carried out to evaluate four candidate materials for high temperature capacitor dielectric applications. The materials investigated were polybenzimidazole polymer and three aramid papers: Voltex 450, Nomex 410, and Nomex M 418, an aramid paper containing 50 percent mica. The samples were heat treated for six hours at 60 C and the direct current and 60 Hz alternating current breakdown voltages of both dry and impregnated samples were obtained in a temperature range of 20 to 250 C. The samples were also characterized in terms of their dielectric constant, dielectric loss, and conductivity over this temperature range with an electrical stress of 60 Hz, 50 V/mil present. Additional measurements are underway to determine the volume resistivity, thermal shrinkage, and weight loss of the materials. Preliminary data indicate that the heat treatment of the films slightly improves the dielectric properties with no influence on their breakdown behavior. Impregnation of the samples leads to significant increases in both alternating and direct current breakdown strength. The results are discussed and conclusions made concerning their suitability as high temperature capacitor dielectrics.

Evaluation of high temperature capacitor dielectrics

NASA Technical Reports Server (NTRS)

Hammoud, Ahmad N.; Myers, Ira T.

1992-01-01

Experiments were carried out to evaluate four candidate materials for high temperature capacitor dielectric applications. The materials investigated were polybenzimidazole polymer and three aramid papers: Voltex 450, Nomex 410, and Nomex M 418, an aramid paper containing 50 percent mica. The samples were heat treated for six hours at 60 C and the direct current and 60 Hz alternating current breakdown voltages of both dry and impregnated samples were obtained in a temperature range of 20 to 250 C. The samples were also characterized in terms of their dielectric constant, dielectric loss, and conductivity over this temperature range with an electrical stress of 60 Hz, 50 V/mil present. Additional measurements are underway to determine the volume resistivity, thermal shrinkage, and weight loss of the materials. Preliminary data indicate that the heat treatment of the films slightly improves the dielectric properties with no influence on their breakdown behavior. Impregnation of the samples leads to significant increases in both alternating and direct current breakdown strength. The results are discussed and conclusions made concerning their suitability as high temperature capacitor dielectrics.