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Notes on Heat-Resistant Materials in Britain from Technical Mission October 13 to November 30, 1950

Description: Memorandum presenting a summary of heat-resistant materials obtained from interviews with alloy producers, jet-engine manufacturers, and research laboratories in Britain during October and November 1950. The primary subjects of interest included the properties of materials and service requirements for gas turbines, criteria used for judging and inspecting materials, and research developments of both a practical and fundamental nature in the field.
Date: May 14, 1951
Creator: Freeman, J. W. & Cross, Howard C.
Partner: UNT Libraries Government Documents Department

The Further Development of Heat-Resistant Materials for Aircraft Engines

Description: "The present report deals with the problems involved in the greater utilization and development of aircraft engine materials, and specifically; piston materials, cylinder heads, exhaust valves, and exhaust gas turbine blading. The blades of the exhaust gas turbine are likely to be the highest stressed components of modern power plants from a thermal-mechanical and chemical standpoint, even though the requirements on exhaust valves of engines with gasoline injection are in general no less stringent. For the fire plate in Diesel engines the specifications for mechanical strength and design are not so stringent, and the question of heat resistance, which under these circumstances is easier obtainable, predominates" (p. 1).
Date: September 1946
Creator: Bollenrath, Franz
Partner: UNT Libraries Government Documents Department

Deep Trek High Temperature Electronics Project

Description: This report summarizes technical progress achieved during the cooperative research agreement between Honeywell and U.S. Department of Energy to develop high-temperature electronics. Objects of this development included Silicon-on-Insulator (SOI) wafer process development for high temperature, supporting design tools and libraries, and high temperature integrated circuit component development including FPGA, EEPROM, high-resolution A-to-D converter, and a precision amplifier.
Date: July 31, 2007
Creator: Ohme, Bruce
Partner: UNT Libraries Government Documents Department

Basic Research Needs for Materials Under Extreme Environments. Report of the Basic Energy Sciences Workshop on Materials Under Extreme Environments, June 11-13, 2007

Description: To evaluate the potential for developing revolutionary new materials that will meet demanding future energy requirements that expose materials to environmental extremes.
Date: February 1, 2008
Creator: Wadsworth, J.; Crabtree, G. W.; Hemley, R. J.; Falcone, R.; Robertson, I.; Stringer, J. et al.
Partner: UNT Libraries Government Documents Department

Method for Synthesizing Extremeley High Temperature Melting Materials

Description: The invention relates to a method of synthesizing high-temperature melting materials. More specifically the invention relates to a containerless method of synthesizing very high temperature melting materials such as borides, carbides and transition-metal, lanthanide and actinide oxides, using an Aerodynamic Levitator and a laser. The object of the invention is to provide a method for synthesizing extremely high-temperature melting materials that are otherwise difficult to produce, without the use of containers, allowing the manipulation of the phase (amorphous/crystalline/metastable) and permitting changes of the environment such as different gaseous compositions.
Date: November 22, 2005
Creator: Saboungi, Marie-Louise and Glorieux, Benoit
Partner: UNT Libraries Government Documents Department

Evolution of microstructure and mechanical properties in laser induced reaction coating of Al{sub 2}O{sub 3} on SiC/Al{sub 2}O{sub 3} composite

Description: Protection of a SiC(p)/Al2O3 composite (SiC particulate-reinforced Al{sub 2}O{sub 3}-matrix) at high temperature from deleterious reactions occurring within and with the surrounding environment is required for high temperature applications. Development of a continuous Al2O3 coating on SiC(p)/Al2O3 ceramic composite for such protection is achieved using the laser assisted in-situ reaction technique. The as-deposited alumina coating was analyzed using optical microscopy and XRD. The coated samples were also evaluated for mechanical properties using 3-point bend tests.
Date: December 31, 1996
Creator: Dahotre, N.B.; Xiao, C.; Boss, W.; McCay, M.H. & McCay, T.D.
Partner: UNT Libraries Government Documents Department

A model for residual stress evolution in air-plasma-sprayed zirconia thermal barrier coatings

Description: Ruby fluorescence spectroscopy indicates that residual stress in air-plasma-sprayed zirconia thermal barrier coatings is a function of the local interface geometry. The stress profile of a simulated rough interface characterized by ``peaks'' and ``valleys'' was modeled with a finite-element approach that accounted for thermal mismatch, oxide scale growth, and top coat sintering. Dependence of the stress profile on interface geometry and microstructure was investigated, and the results were compared with measured stresses.
Date: February 28, 2000
Creator: Nair, B. G.; Singh, J. P. & Grimsditch, M.
Partner: UNT Libraries Government Documents Department

Surface modification: advantages, techniques, and applications

Description: Adequate performance of materials at elevated temperatures is a potential problem in many systems within the chemical, petroleum, process, and power-generating industries. Degradation of materials occurs because of interaction between the structural material and the exposure environment. These interactions are generally undesired chemical reactions that can lead to accelerated wastage and alter the functional requirements and/or structural integrity of the materials. Therefore, material selection for high-temperature applications must be based not only on a material strength properties but also on resistance to the complex environments prevalent in the anticipated exposure environment. As plants become larger, the satisfactory performance and reliability of components play a greater role in plant availability and economics. However, system designers are becoming increasingly concerned with finding the least expensive material that will satisfactorily perform the design function for the desired service life. This present paper addresses the benefits of surface modification and identified several criteria for selection and application of modified surfaces in the power sector. A brief review is presented on potential methods for modification of surfaces, with the emphasis on coatings. In the final section of the paper, several examples address the requirements of different energy systems and surface modification avenues that have been applied to resolve the issues.
Date: March 1, 2000
Creator: Natesan, K.
Partner: UNT Libraries Government Documents Department

Plastic Heat Exchangers for Waste Heat Recovery

Description: Metallic corrosion is one of the major impediments to using the large amounts of heat available in flue and exhaust gases. Our approach is to develop plastic coatings to eliminate this corrosion problem and make this waste heat available economically. The advantages of plastics and their limitations in this application are discussed. Laboratory testing in an acid-condensing environment has been performed on numerous plastics and has identified several plastics with good potential as corrosion barriers. Polyphenylene sulfide, in particular, has resisted sulfuric acid attack for over 5000 hours and can be used at temperatures up to 300 C.
Date: September 1983
Creator: Roach, P. D. & Holtz, Robert E.
Partner: UNT Libraries Government Documents Department

Interfacial coatings for ceramic-matrix composites -- Volume 2. Final report

Description: This report summarizes the task conducted to examine various activities on interface development for ceramic-matrix composites (CMCs) intended for high-temperature applications. While several articles have been published on the subject of CMC interfaces, the purpose of this report is to describe the various ongoing efforts on interface concepts, material selection, and issues related to processing methods employed for developing interface coatings. The most exciting and new development in the field is the discovery of monazite as a potential interface material for mullite- and alumina-based composites. Monazite offers two critical properties to the CMC system; a weakly bonded layer due to its non-wetting behavior and chemical compatibility with both alumina and mullite up to very high temperatures (> 1,600 C). Other interesting concepts with intensive material development efforts are also being pursued and a brief discussion of these are given in the main text. While demonstration of new interface concepts seems to be the primary objective in most studies, difficulties in processing of interface coatings and designing reliable test methods for determining interface properties have actually retarded the progress. Some of the concepts appear to be simple in nature but require sophisticated processing schemes to develop the coatings. Multilayered coatings with each layer serving specific function are also being proposed. Recent studies also show that significant degradation in fiber strength (30--50%) can result from merely applying the interface coating. These factors have compounds the complexity of interface tailoring in CMCs leading to a need for specific solution for a specific CMC system.
Date: June 9, 1998
Creator: Sambasivan, S.
Partner: UNT Libraries Government Documents Department

User manual for SPLASH (Single Panel Lamp and Shroud Helper).

Description: The radiant heat test facility develops test sets providing well-characterized thermal environments, often representing fires. Many of the components and procedures have become standardized to such an extent that the development of a specialized design tool to determine optimal configurations for radiant heat experiments was appropriate. SPLASH (Single Panel Lamp and Shroud Helper) is that tool. SPLASH is implemented as a user-friendly, Windows-based program that allows a designer to describe a test setup in terms of parameters such as number of lamps, power, position, and separation distance. This document is a user manual for that software. Any incidental descriptions of theory are only for the purpose of defining the model inputs. The theory for the underlying model is described in SAND2005-2947 (Ref. [1]). SPLASH provides a graphical user interface to define lamp panel and shroud designs parametrically, solves the resulting radiation enclosure problem for up to 2500 surfaces, and provides post-processing to facilitate understanding and documentation of analyzed designs.
Date: February 1, 2006
Creator: Larsen, Marvin Elwood
Partner: UNT Libraries Government Documents Department

Hard quasiamorphous carbon -- A prospective construction material for micro-electro-mechanical systems

Description: A new form of sp{sup 3}/sp{sup 2} carbon has been fabricated which exhibits a large number of valuable properties. This material combines low density ({le} 1.65 g/cm{sup 3}), low stress ({le} 0.05 GPa), low thermal expansion(1.6 x 10{sup {minus}6} K{sup {minus}1}) with high hardness ({approximately} 30 GPa), modulus ({approximately} 200 GPa), cracking threshold ({ge} 3 N), fracture toughness ({ge} 10 MPa-m{sup 1/2}), long-term thermal stability ({ge} 450 C in air and {ge} 600 C without oxygen), extremely high thermal shock resistance, excellent interface and adhesion to silicon, metals, and ceramics and an absolute resistance to the silicon etching acids. Mot of its properties are actually constant up to 700 K. The material combines a basically amorphous structure with one-axis anisotropy and a graphite-like layered arrangement with a length scale of the modulation about 14 {angstrom}. The authors refer to this quasi-amorphous material as QUASAM. This paper describes QUASAM synthesis conditions, growth front planarity and material characterization with high-resolution x-ray diffraction, positron annihilation spectroscopy, atomic force microscopy and micro-Raman spectroscopy. In addition the mechanical and thermal examination of QUASAM and QUASAM/Si will be presented in terms of micro-electro-mechanical systems (MEMS) and the technology prospective requirements of MEMS.
Date: January 1, 1996
Creator: Dorfman, B.F.; Asoka-Kumar, P.; Zhu, Q.; Pollak, F.H. & Wan, J.Z.
Partner: UNT Libraries Government Documents Department

High temperature structural silicides

Description: Structural silicides have important high temperature applications in oxidizing and aggressive environments. Most prominent are MoSi{sub 2}-based materials, which are borderline ceramic-intermetallic compounds. MoSi{sub 2} single crystals exhibit macroscopic compressive ductility at temperatures below room temperature in some orientations. Polycrystalline MoSi{sub 2} possesses elevated temperature creep behavior which is highly sensitive to grain size. MoSi{sub 2}-Si{sub 3}N{sub 4} composites show an important combination of oxidation resistance, creep resistance, and low temperature fracture toughness. Current potential applications of MoSi{sub 2}-based materials include furnace heating elements, molten metal lances, industrial gas burners, aerospace turbine engine components, diesel engine glow plugs, and materials for glass processing.
Date: March 1, 1997
Creator: Petrovic, J. J.
Partner: UNT Libraries Government Documents Department

Effects of high-temperature environments on flaw generation and fracture behavior of SiC/SiC composites

Description: Flaw generation and fracture behavior of Nicalon-fiber-reinforced SiC matrix composites are influenced by high temperatures. Therefore, the authors evaluated the effects of temperature by measuring the strength of these composites at several temperatures ranging from 800 to 1,300 C, and by characterizing their microstructure. While composite strength increased from {approx}400 MPa at room temperature to {approx}532 MPa at 800 C, it decreased to {approx}270 MPa at 1,300 C. Such degradation of composite strength at high temperature is believed to be partly due to fiber degradation. In-situ fiber strength of composites tested at room and elevated temperatures was estimated by fractographic techniques. The in-situ strength of fibers in composites was significantly lower than that of as-received fibers. This decrease is believed to be related to flaws that develop during processing and to exposure to elevated-temperature service environments.
Date: February 1, 1995
Creator: Singh, J.P. & Singh, D.
Partner: UNT Libraries Government Documents Department

Topical report to Morgantown Energy Technology Center for the interfacial coatings for ceramic-matrix composites

Description: This report summarizes the task conducted to examine various activities on interface development for ceramic-matrix composites (CMCs) intended for high-temperature applications. While several articles have been published on the subject of CMC interfaces, the purpose of this report is to describe the various ongoing efforts on interface concepts, material selection, and issues related to processing methods employed for developing interface coatings. The most exciting and new development in the field is the discovery of monazite as a potential interface material for mullite- and alumina-based composites. Monazite offers two critical properties to the CMC system; a weakly bonded layer due to its non-wetting behavior and chemical compatibility with both alumina and mullite up to very high temperatures (> 1,600 C). A description of the Department of Energy-related activities and some thoughts on processing issues, interface testing, and effects of processing on fiber strength are given.
Date: January 9, 1997
Partner: UNT Libraries Government Documents Department

Thermal imaging measurement and correlation of thermal diffusivity in continuous fiber ceramic composites

Description: Continuous fiber ceramic matrix composites (CFCCs) are currently being developed for a variety of high-temperature applications, including use in advanced heat engines. For such composites, knowledge of porosity distribution and presence of defects is important for optimizing mechanical and thermal behavior of the components. The assessment of porosity and its distribution is also necessary during composite processing to ensure component uniformity. To determine the thermal properties of CFCC materials, and particularly for detecting defects and nonuniformities, the authors have developed an infrared thermal imaging method to provide a single-shot full-field measurement of thermal diffusivity distributions in large components. This method requires that the back surface of a specimen receives a thermal pulse of short duration and that the temperature of the front surface is monitored as a function of time. The system has been used to measure thermal diffusivities of several CFCC materials with known porosity or density values, including SYLRAMIC{trademark} SiC/SiNC composite samples from Dow Corning and SiC/SiC and enhanced SiC/SiC samples from DuPont Lanxide Composites, to determine the relationship of thermal diffusivity to component porosity or density.
Date: September 1, 1997
Creator: Sun, J.G.; Deemer, C.; Ellingson, W.A.; Easler, T.E.; Szweda, A. & Craig, P.A.
Partner: UNT Libraries Government Documents Department

An analysis of creep crack growth of interface cracks in layered/graded materials

Description: In this study, the growth behavior of interface cracks in bimaterials and in layered materials resulting from the creep cavitation was studied. The growth model includes the effects of material deposition resulting from the growth of creep cavities on the crack tip stress fields. The results indicate that in layered materials under identical applied loading, the location of the interface crack strongly influence the amplitude of the stress field at steady-state. Due to large variation in the distribution of the stresses ahead of the interface cracks at creep regime, depending upon the crack location, the creep crack growth rates will be significantly different from each other under identical loading for a given layered material.
Date: July 1, 1997
Creator: Biner, S.B.
Partner: UNT Libraries Government Documents Department

Synthesis of silicon nitride powders in pulsed RF plasmas

Description: Nanometer size silicon nitride particles are synthesized using a pulsed radio frequency plasma technique. The plasma is modulated with a square-wave on/off cycle of varying period to control size and morphology and to deduce the growth kinetics. In situ laser light scattering and ex situ particle analysis are used to study the nucleation and growth. For SiH{sub 4}/Ar plasmas which nucleate silicon particles, an initial extremely rapid growth phase is followed by a slower growth rate, approaching the rate of thin film deposition on adjacent flat surfaces. In SiH{sub 4}/NH{sub 3} plasmas, silicon nitride particle size can be tightly controlled by adjusting the plasma-on time. The size dispersion of the particles is large and is consistent with a process of continual nucleation during the plasma-on period. The observed polydispersity differs dramatically from that reported from other laboratories.
Date: May 1, 1995
Creator: Buss, R.J.; Ho, P. & Babu, S.V.
Partner: UNT Libraries Government Documents Department

Synthesis and Design of Silicide Intermetallic Materials

Description: 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 US 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 US processing industries. The program presently has a number of industrial connections, including a CRADA with Johns Manville Corporation targeted at the area of MoSi{sub 2}-based high temperature materials 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. With the Exotherm Corporation, they are developing advanced silicide powders for the fabrication of silicide materials with tailored and improved properties for industrial applications. In October 1998, the authors initiated a new activity funded by DOE/OIT on ``Molybdenum Disilicide Composites for Glass Processing Sensors''. With Accutru International Corporation, they are developing silicide-based protective sheaths for self-verifying temperature sensors which may be used in glass furnaces and other industrial applications. With Combustion Technology Inc., they are developing silicide-based periscope sight tubes for the direct observation of glass melts.
Date: May 14, 1999
Creator: Petrovic, J. J.; Castro, R. G.; Vaidya, R. U. & Park, Y.
Partner: UNT Libraries Government Documents Department

Corrosion protection of SiC-based ceramics with CVDMullite coatings

Description: Silicon carbide ceramics are the leading candidate materials for use as heat exchangers in advanced combined cycle power plants because of their unique combination of high temperature strength, high thermal conductivity, excellent thermal shock resistance, and good high temperature stability and oxidation resistance. Ceramic coatings are being considered for diesel engine cylinder liners, piston caps, valve faces and seats, piston rings, and for turbine components such as combustors, blades, stators, seals, and bearings. Under such conditions ceramics are better suited to high temperature environments than metals. For the first time, adherent crystalline mullite coatings have been chemically vapor deposited onto SiC substrates to enhance its corrosion/oxidation resistance. Thermodynamic and kinetic considerations have been utilized to produce mullite coatings with a variety of growth rates, compositions, and morphologies. The flexibility of processing can be exploited to produce coated ceramics with properties tailored to specific applications and varied corrosive environments. These corrosive environments include thermal, Na{sub 2}SO{sub 4}, O{sub 2} and coal slag.
Date: May 1, 1997
Creator: Sarin, V. & Auger, M.
Partner: UNT Libraries Government Documents Department

Alumina composites for oxide/oxide fibrous monoliths

Description: Most work on ceramic fibrous monoliths (FMs) has focused on the Si{sub 3}N{sub 4}/BN system. In an effort to develop oxidation-resistant FMs, several oxide systems have recently been examined. Zirconia-toughened alumina and alumina/mullite appear to be good candidates for the cell phase of FMs. These composites offer higher strength and toughness than pure alumina and good high-temperature stability. By combining these oxides, possibly with a weaker high-temperature oxide as the cell-boundary phase, it should be possible to product a strong, resilient FM that exhibits graceful failure. Several material combinations have been examined. Results on FM fabrication and microstructural development are presented.
Date: March 1, 2000
Creator: Cruse, T. A.; Polzin, B. J.; Picciolo, J. J.; Singh, D.; Tsaliagos, R. N. & Goretta, K. C.
Partner: UNT Libraries Government Documents Department