SEARCH · Engineering Papers

Results for “ceramic processing”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16

All sources NASA NTRS DOE OSTI

NASA NTRS1996

Manufacturing Superconducting Cables

Process proposed for manufacture of cables containing ceramic high-temperature-superconductor YBa(2)Cu(3)O(7-a). For protection, superconducting ceramic encapsulated before activation. Cables carry electrical current with little or no loss of power when cooled to or below temperatures of about minus 200 degrees C. Process accommodates brittle nature of YBa(2)Cu(3)O(7-a) and economical and readily controllable. Also flexible in sense modified to accommodate variety of precursor materials to be processed into YBa(2)Cu(3)O(7-a).

England, Christopher↗

NASA NTRS1974

Process for fabrication of stabilized aluminum phosphate fibers

Ceramic possesses ideal property combination of high refractoriness and low thermal expansion. Fiber exceeds performance of fused silica fibers at high temperatures. It shrinks less, does not devitrify into unstable cristobalite structure, and is potentially less sensitive to impurities. Might be used for high-temperature insulation, fire protection, composites, and refractories.

Ormiston, T. J.↗

NASA NTRS2003

Light Weight Biomorphous Cellular Ceramics from Cellulose Templates

Bimorphous ceramics are a new class of materials that can be fabricated from the cellulose templates derived from natural biopolymers. These biopolymers are abundantly available in nature and are produced by the photosynthesis process. The wood cellulose derived carbon templates have three- dimensional interconnectivity. A wide variety of non-oxide and oxide based ceramics have been fabricated by template conversion using infiltration and reaction-based processes. The cellular anatomy of the cellulose templates plays a key role in determining the processing parameters (pyrolysis, infiltration conditions, etc.) and resulting ceramic materials. The processing approach, microstructure, and mechanical properties of the biomorphous cellular ceramics (silicon carbide and oxide based) have been discussed.

Singh, Mrityunjay↗

NASA NTRS1993

Thermal spray forming of refractory sample ampoule cartridges for single crystal growth space furnaces

A thermal spray process is being used to build up refractory metals and ceramics into a containment cartridge for high temperature, single crystal semiconductor growth experiments. This process uses high energy plasma inside a low pressure (100-200 torr) inert environment to apply layers of material onto a removable mandrel. A variety of materials are being characterized and evaluated against a demanding set of requirements, including high service temperature (1700 C), oxidation resistance, and resistance to liquid metal attack. Techniques to spray form refractory metals (tungsten, molybdenum, niobium, tantalum) and ceramics (alumina, boron nitride) are being developed in the Plasma Spray Cell at Marshall Space Flight Center. These plasma spray formed materials have been evaluated for mechanical properties, density, microstructure, and resistance to liquid metal attack. Forming techniques and the resultant mechanical and metallurgical properties will be presented.

Zimmerman, Frank↗

NASA NTRS1993

Thermal spray forming of refractory sample ampoule cartridges for single crystal growth space furnaces

Zimmerman, Frank↗

NASA NTRS1998

Test Standard Developed for Determining the Slow Crack Growth of Advanced Ceramics at Ambient Temperature

The service life of structural ceramic components is often limited by the process of slow crack growth. Therefore, it is important to develop an appropriate testing methodology for accurately determining the slow crack growth design parameters necessary for component life prediction. In addition, an appropriate test methodology can be used to determine the influences of component processing variables and composition on the slow crack growth and strength behavior of newly developed materials, thus allowing the component process to be tailored and optimized to specific needs. At the NASA Lewis Research Center, work to develop a standard test method to determine the slow crack growth parameters of advanced ceramics was initiated by the authors in early 1994 in the C 28 (Advanced Ceramics) committee of the American Society for Testing and Materials (ASTM). After about 2 years of required balloting, the draft written by the authors was approved and established as a new ASTM test standard: ASTM C 1368-97, Standard Test Method for Determination of Slow Crack Growth Parameters of Advanced Ceramics by Constant Stress-Rate Flexural Testing at Ambient Temperature. Briefly, the test method uses constant stress-rate testing to determine strengths as a function of stress rate at ambient temperature. Strengths are measured in a routine manner at four or more stress rates by applying constant displacement or loading rates. The slow crack growth parameters required for design are then estimated from a relationship between strength and stress rate. This new standard will be published in the Annual Book of ASTM Standards, Vol. 15.01, in 1998. Currently, a companion draft ASTM standard for determination of the slow crack growth parameters of advanced ceramics at elevated temperatures is being prepared by the authors and will be presented to the committee by the middle of 1998. Consequently, Lewis will maintain an active leadership role in advanced ceramics standardization within ASTM. In addition, the authors have been and are involved with several international standardization organizations including the Versailles Project on Advanced Materials and Standards (VAMAS), the International Energy Agency (IEA), and the International Organization for Standardization (ISO). The associated standardization activities involve fracture toughness, strength, elastic modulus, and the machining of advanced ceramics.

Choi, Sung R.↗

NASA NTRSDate not supplied

Liquid Droplet Printing

The center has recently invested in a new additive manufacturing technology known as liquid metal jetting or liquid droplet printing. The Additec ElemX machine’s process utilizes wire feedstock fed into a ceramic crucible, where it is melted and ejected by pulsed Lorentz force using an external coil. The team will start with material characterization of various commercially available aluminum alloys to establish process parameters, repeatability, mechanical properties, and microstructure. Future research will consider additional alloys and explore concepts that may potentially adapt the technology for relevance in zero or low gravity environments. The printer has a 12”x12”x4.7” build volume and 0.24mm minimum layer height, with surface finishes comparable to sand castings.

liquid droplet printing↗

NASA NTRS1984

Oxidation resistance of silicon ceramics

Oxidation resistance, and examples of oxidation of SiC, Si3N4 and sialon are reviewed. A description is given of the oxidation mechanism, including the oxidation product, oxidation reaction and the bubble size. The oxidation reactions are represented graphically. An assessment is made of the oxidation process, and an oxidation example of silicon ceramics is given.

Yasutoshi, H.↗

NASA NTRS2007

Rapid Fabrication of Carbide Matrix/Carbon Fiber Composites

Composites of zirconium carbide matrix material reinforced with carbon fibers can be fabricated relatively rapidly in a process that includes a melt infiltration step. Heretofore, these and other ceramic matrix composites have been made in a chemical vapor infiltration (CVI) process that takes months. The finished products of the CVI process are highly porous and cannot withstand temperatures above 3,000 F (approx.1,600 C). In contrast, the melt-infiltration-based process takes only a few days, and the composite products are more nearly fully dense and have withstood temperatures as high as 4,350 F (approx.2,400 C) in a highly oxidizing thrust chamber environment. Moreover, because the melt- infiltration-based process takes much less time, the finished products are expected to cost much less. Fabrication begins with the preparation of a carbon fiber preform that, typically, is of the size and shape of a part to be fabricated. By use of low-temperature ultraviolet-enhanced chemical vapor deposition, the carbon fibers in the preform are coated with one or more interfacial material(s), which could include oxides. The interfacial material helps to protect the fibers against chemical attack during the remainder of the fabrication process and against oxidation during subsequent use; it also enables slippage between the fibers and the matrix material, thereby helping to deflect cracks and distribute loads. Once the fibers have been coated with the interfacial material, the fiber preform is further infiltrated with a controlled amount of additional carbon, which serves as a reactant for the formation of the carbide matrix material. The next step is melt infiltration. The preform is exposed to molten zirconium, which wicks into the preform, drawn by capillary action. The molten metal fills most of the interstices of the preform and reacts with the added carbon to form the zirconium carbide matrix material. The zirconium does not react with the underlying fibers because they are protected by the interfacial material(s). The success of the melt-infiltration step depends on interface material selection and uniform coating of the fibers, infiltration with the correct amount of carbon, and careful control of temperature and rate of heating.

Williams, Brian E.↗

NASA NTRS2000

Thermophysical and Thermomechanical Properties of Thermal Barrier Coating Systems

Thermal barrier coatings have been developed for advanced gas turbine and diesel engine applications to improve engine reliability and fuel efficiency. However, the issue of coating durability under high temperature cyclic conditions is still of major concern. The coating failure is closely related to thermal stresses and oxidation in the coating systems. Coating shrinkage cracking resulting from ceramic sintering and creep at high temperatures can further accelerate the coating failure process. The purpose of this paper is to address critical issues such as ceramic sintering and creep, thermal fatigue and their relevance to coating life prediction. Novel test approaches have been established to obtain critical thermophysical and thermomechanical properties of the coating systems under near-realistic temperature and stress gradients encountered in advanced engine systems. Emphasis is placed on the dynamic changes of the coating thermal conductivity and elastic modulus, fatigue and creep interactions, and resulting failure mechanisms during the simulated engine tests. Detailed experimental and modeling results describing processes occurring in the thermal barrier coating systems provide a framework for developing strategies to manage ceramic coating architecture, microstructure and properties.

Zhu, Dongming↗

NASA NTRS2019

Optimization of Aluminum-Tin Ink Composition and Sintering in Atmospheric Conditions

This study will focus on the basics of generating an aluminum-tin ink that can sinter in air and exhibits properties near that of a solid aluminum-tin alloy. Sintering temperatures will also be assessed in this study. Once the optimal aluminum ink composition is determined, the optimal ink thickness for homogeneous sintering must be determined by additional experimentation. Additive manufacturing is a rapidly developing and growing manufacturing process and has proven successful in many different ways. Processes, such as extrusion three-dimensional (3D) printing and selective laser melting (SLM), have proven to work but have limitations, such as material capabilities or density issues. SLM is a revolutionary process for additive manufacturing of metals but cannot be used in outer space due to the need for metallic powder which would diffuse into the atmosphere in a zero-gravity environment. For this reason, metallic ink additive manufacturing is a potential solution. Work is being done on metallic ink additive manufacturing in a vacuum for electrical applications. This project has focused on developing an aluminum-tin metallic ink that can sinter without the need of a vacuum or inert gas-purged atmosphere in order to prevent oxidation of the aluminum by adding flux. Once a potential ink composition has been determined through sintering of small disks and thin layers of ink, the ink may be studied with a multimaterial 3D printer at NASA Marshall Space Flight Center (MSFC) in future experiments. If successful, this aluminum-tin ink will be capable for use on the International Space Station to make replacement parts quickly. Along with its zero-gravity advantages, this ink may also have applications on Earth because it may be extruded on a substrate with precise ceramic tips in a 3D printing process. This would allow the fabrication of precise, complex shapes and may generate a much faster and more efficient printing process as compared with traditional powder bed additive manufacturing processes. The process would not be limited by a small building volume because the system would not require an enclosed chamber.

Courtright, Z. S.↗

NASA NTRS2025

A Review of Direct Ink Writing of Polymer Derived Ceramics

With the growing demand for materials capable of withstanding extreme temperatures and pressures, ceramic components with exceptional corrosion resistance and reliable mechanical properties have experienced a significant surge in demand. However, traditional ceramic forming methods involve high-temperatures and energy-intensive processes that often struggle to produce complex parts or composites efficiently. Polymer-Derived Ceramics (PDCs) offer a transformative solution by using polymeric precursors that can be converted into a wide variety of silicon-based and non-silicon-based ceramics through heat treatment. The polymeric nature of PDC precursors enables the fabrication of geometrically intricate components using conventional polymer-forming techniques at significantly lower processing temperatures. Furthermore, PDCs are well-suited for additive manufacturing (AM), allowing the production of complex structural and functional components through cost-effective, low-temperature processes. By leveraging the diverse properties of PDC materials – each with unique advantages and limitations – manufacturers can optimise performance for specific applications. This review provides an overview of the types of PDCs developed to date and their broad range of applications. Specifically, it delves into the Direct Ink Writing (DIW) process, exploring its rheological requirements and the critical role of fillers in tailoring the rheological properties of polymeric precursors to meet the specific demands of DIW.

Victoria Bishop↗

NASA NTRS1989

Characterization of ceramics and intermetallics fabricated by self-propagating high-temperature synthesis

Three efforts aimed at investigating the process of self-propagating high temperature synthesis (SHS) for the fabrication of structural ceramics and intermetallics are summarized. Of special interest was the influence of processing variables such as exothermic dopants, gravity, and green state morphology in materials produced by SHS. In the first effort directed toward the fabrication of SiC, exothermic dopants of yttrium and zirconium were added to SiO2 or SiO2 + NiO plus carbon powder mix and processed by SHS. This approach was unsuccessful since it did not produce the desired product of crystalline SiC. In the second effort, the influence of gravity was investigated by examining Ni-Al microstructures which were produced by SHS combustion waves traveling with and opposite the gravity direction. Although final composition and total porosities of the combusted Ni-Al compounds were found to be gravity independent, larger pores were created in those specimens which were combusted opposite to the gravity force direction. Finally, it was found that green microstructure has a significant effect on the appearance of the combusted piece. Severe pressing laminations were observed to arrest the combustion front for TiC samples.

Hurst, Janet B.↗

NASA NTRS1995

Fabrication of advanced electrochemical energy materials using sol-gel processing techniques

Advanced materials play an important role in electrochemical energy devices such as batteries, fuel cells, and electrochemical capacitors. They are being used as both electrodes and electrolytes. Sol-gel processing is a versatile solution technique used in fabrication of ceramic materials with tailored stoichiometry, microstructure, and properties. The application of sol-gel processing in the fabrication of advanced electrochemical energy materials will be presented. The potentials of sol-gel derived materials for electrochemical energy applications will be discussed along with some examples of successful applications. Sol-gel derived metal oxide electrode materials such as V2O5 cathodes have been demonstrated in solid-slate thin film batteries; solid electrolytes materials such as beta-alumina for advanced secondary batteries had been prepared by the sol-gel technique long time ago; and high surface area transition metal compounds for capacitive energy storage applications can also be synthesized with this method.

Chu, C. T.↗

NASA NTRS1972

Economic analysis of crystal growth in space

Many advanced electronic technologies and devices for the 1980's are based on sophisticated compound single crystals, i.e. ceramic oxides and compound semiconductors. Space processing of these electronic crystals with maximum perfection, purity, and size is suggested. No ecomonic or technical justification was found for the growth of silicon single crystals for solid state electronic devices in space.

Ulrich, D. R.↗

NASA NTRS1987

The mechanics of manufacturing in space

The history of the U.S. manned space-flight program is briefly reviewed, with an emphasis on the development of materials-processing technology, and space-manufacturing aspects of the Space Station and proposed lunar and Martian bases are discussed. Consideration is given to the Mercury, Gemini, Apollo, and Apollo-Soyuz missions; Space Shuttle materials-processing experiments; plans for processing electronics crystals, metals, glasses and ceramics, biological materials, and fluids and chemicals on the Space Station; extraction of O2, Fe, Ni, and H2 from lunar materials for use as propellants and in space construction (e.g., of solar power satellites); and the requirements for a permanent base on Mars.

Wade, D. C.↗

NASA NTRS2000

Lightweight Chambers for Thrust Cell Applications

Traditional metals like steel and copper alloys have been used for many years to fabricate injector and chamber components of thruster assemblies. While the materials perform well, reducing engine weights would help existing and future vehicles gain performance and payload capability. It may now be possible to reduce current thruster weights up to 50% by applying composite materials. In this task, these materials are being applied to an existing thrust cell design to demonstrate new fabrication processes and potential weight savings. Two ceramic matrix composite (CMC) designs, three polymer matrix composite (PMC) designs, and two metal matrix composite (MMC) designs are being fabricated as small chamber demonstration units. In addition, a new alloy of copper, chrome, and niobium (Cu-8Cr-4Nb) is being investigated for thrust chamber liners since it offers higher strength and increased cycle life over traditional alloys. This new alloy is being used for the liner in each MMC and PMC demonstration unit. During June-August of 2000, hot-fire testing of each unit is planned to validate designs in an oxygen/hydrogen environment at chamber pressures around 850 psi. Although the weight savings using CMC materials is expected to be high, they have proven to be much harder to incorporate into chamber designs based on current fabrication efforts. However, the PMC & MMC concepts using the Cu-8Cr-4Nb liner are nearly complete and ready for testing. Additional efforts intend to use the PMC & MMC materials to fabricate a full size thrust chamber (60K lb(sub f) thrust class). The fabrication of this full size unit is expected to be complete by October 2000, followed by hot-fire testing in November-December 2000.

Elam, S.↗

NASA NTRS2002

Rapid Prototyping of Continuous Fiber Reinforced Ceramic Matrix Composites

For ceramics to be used as structural components in high temperature applications, their fracture toughness is improved by embedding continuous ceramic fibers. Ceramic matrix composite (CMC) materials allow increasing the overall operating temperature, raising the temperature safety margins, avoiding the need for cooling, and improving the damping capacity, while reducing the weight at the same time. They also need to be reliable and available in large quantities as well. In this paper, an innovative rapid prototyping technique to fabricate continuous fiber reinforced ceramic matrix composites is described. The process is simple, robust and will be widely applicable to a number of high temperature material systems. This technique was originally developed at the University of Delaware Center for Composite Materials (UD-CCM) for rapid fabrication of polymer matrix composites by a technique called automated tow placement or ATP. The results of mechanical properties and microstructural characterization are presented, together with examples of complex shapes and parts. It is believed that the process will be able to create complex shaped parts at an order of magnitude lower cost than current CVI and PIP processes.

Vaidyanathan, R.↗