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Results for “TITANIUM CARBIDE”

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.

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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Evaluation of materials for sliding at 600F-1800F in air.

Oscillating sliding tests were conducted in air under the following operating conditions: 500 psi, 600 F; 500 psi, 1200 F; 500 psi, 1800 F; 1500 psi, 1800 F; 3000 psi, 1800 F. Sixteen materials combinations were tested including ceramics, alloys and eutectics, cermets, and combinations of these. Friction, wear and surface damage (including surface roughening) were studied. The most outstanding materials combination was found to be nickel-molybdenum-bonded titanium carbide cermet sliding against dense magnesia stabilized ZrO2.

Finkin, E. F.↗
NASA NTRS1975

Investigation to develop a method to apply diffusion barrier to high strength fibers

A radio frequency powered ion plating process was used to apply the diffusion barriers of aluminum oxide, yttrium oxide, hafnium oxide and titanium carbide to a substrate tungsten fiber. Each of the coatings was examined as to its effect on both room temperature strength and tensile strength of the base tungsten fiber. The coated fibers were then overcoated with a nickel alloy to become single cell diffusion couples. These diffusion couples were exposed to 1093 C for 24 hours, cycled between room temperature and 1093 C, and given a thermal anneal for 100 hours at 1200 C. Tensile testing and metallographic examinations determined that the hafnium oxide coating produced the best high temperature diffusion barrier for tungsten of the four coatings.

Veltri, R. D.↗
NASA NTRS1979

Ion-beam-textured graphite

Results of evaluation of seven different materials (copper, tantalum, titanium carbide, soot, smooth pyrolytic graphite, and ion-beam-textured graphite) for low secondary-electron emitting surface for depressed collects in microwave amplifiers indicate that ion-beam-textured graphite shows greatest potential for use.

Curren, A. N.↗
NASA NTRS1977

Secondary-electron-emission properties of conducting surfaces with application to multistage depressed collectors for microwave amplifiers

To improve the efficiency of high power microwave tubes, low secondary electron yield electrode surface for use in depressed collectors are needed. The secondary emission characteristics of a number of materials were investigated. The materials studied were beryllium, carbon (soot and pyrolytic graphite), copper, titanium carbide, and tantalum. Both total secondary yield delta and relative reflected primary yield were measured. These measurements were made in conjunction with Auger spectroscopy so that the secondary emission characteristics could be determined as a function of surface contamination or purity. The results show that low atomic weight elements, such as beryllium and carbon, have the lowest reflected primary yield and that roughening the surface of an electrode can markedly decrease secondary yield both for delta and reflected primaries. All factors considered, a roughened pyrolytic graphite surface showed the greatest potential for use as an electrode surface in depressed collectors.

Forman, R.↗
NASA NTRS1978

Secondary electron emission properties of conducting surfaces for use in multistage depressed collectors

An Auger spectrometer in ultrahigh vacuum was used to measure the secondary emission properties of a number of candidate collector-materials including beryllium, carbon, (soot and pyrolytic graphite), copper, titanium carbide and tantalum. The advantage of the technique used is that the surface chemical constituents could be determined just before the secondary emission characteristics of the surface were measured. Pyrolytic graphite roughened by sputter etching showed the most favorable results for depressed collector use.

Forman, R.↗
NASA NTRS1980

Improved adherence of T1C coatings to steel

Modified process for RF sputtering of titanium carbide coatings onto 440-C steel has resulted in improved adherence. Small partial pressure of nitrogen, approximately 0.5 percent, during first minutes of deposition markedby improved adherence, friction, and wear properties when compared with coatings applied on sputter-etched surfaces, or oxidized surfaces or in presence of small oxygen partial pressure. X-ray photoelectron spectroscopy and X-ray diffraction were used to characterize resultant coatings.

Brainard, W. A.↗
NASA NTRS1981

Sandblasting nozzle

A nozzle for use with abrasive and/or corrosive materials is formed of sintered ceramic compositions having high temperature oxidation resistance, high hardness and high abrasion and corrosion resistance. The ceramic may be a binary solid solution of a ceramic oxide and silicon nitride, and preferably a ternary solid solution of a ceramic oxide, silicon nitride and aluminum nitride. The ceramic oxide is selected from a group consisting of Al2O3, Y2O3 and Cr2O3, or mixtures of those compounds. Titanium carbide particles are dispersed in the ceramic mixture before sintering. The nozzles are encased for protection from external forces while in use by a metal or plastic casing.

Perkins, G. S.↗
NASA NTRS1982

Refractory coatings

A thin sputtered film is discussed which exhibits improved adherence to a substrate and has improved friction and wear characteristics. Each substrate is placed directly below a titanium carbide target of a commercial radiofrequency diode apparatus in a vacuum chamber. Nitrogen is bled into the system through a nozzle resulting in a small partial pressure of about 0.5% to 2.5% during the first two minutes of deposition. The flow of nitrogen is then stopped, and the sputtering ambient is reduced to pure argon through a nozzle without interrupting the sputtering process.

Brainard, W. A.↗
NASA NTRS1984

Breakway friction and dynamic friction/wear measurements of various ceramic materials from 25 C (75 F) to 650 C (1200 F)

This report describes the results of a program designed to evaluate the breakaway friction and dynamic friction/wear characteristics of materials having potential for use as load bearing components in a high-performance high-temperature heavy duty diesel engine. Ten candidate materials were selected, six of which were evaluated under all possible material combinations as both stationary as well as moving breakaway specimens. The remaining materials were evaluated either in the static mode against themselves and all other materials, or against themselves only. Experiments were performed at five temperatures up to 650 C (1200 F) and unit pressures of 700 kPa (100 lb/sq in.), 3500 kPa (500 lb/sq in.), and 7000 kPa (1000 lb/sq in.). Experimental results indicate that under dynamic conditions, four of the ten materials exhibited good to excellent friction/wear characteristics in various material combinations. These materials were: titanium carbide, silicon nitride, silicon carbide (reaction sintered), and Refel (SiC).

Boes, D. J.↗
NASA NTRS1990

Determination of the durability of the fiberoptics in rocket engine environments

The results of a testing program in which selected optical fibers were exposed to extreme environments representative of those experienced on rocket engines are discussed. Included in the experiment are cold-bend testing, a moisture embrittlement test, a thermal cycling test, temperature extremes testing, vibration testing, and shock testing. Two of the fibers selected, the titanium-carbide-coated and the aluminum-jacketed silica samples succeeded in passing all the tests without a failure.

Delcher, R.↗
NASA NTRS1991

Instellar grains within interstellar grains

The discovery of crystals of titanium carbide in an interstellar graphite spherule is reported. The new species is particularly interesting in that it came in a protective wrapping (the graphite spherule) which eliminated the possibility of chemical alteration during its residence in the interstellar medium and in the meteorite in which it was discovered.

Bernatowicz, Thomas J.↗
NASA NTRS1991

Simplified micromechanical equations for thermal residual stress analysis of coated fiber composites

The fabrication of metal matrix composites poses unique problems to the materials engineer. The large thermal expansion coefficient (CTE) mismatch between the fiber and matrix leads to high tensile residual stresses at the fiber/matrix (F/M) interface which could lead to premature matrix cracking during cooldown. Fiber coatings could be used to reduce thermal residual stresses. A simple closed form analysis, based on a three phase composite cylinder model, was developed to calculate thermal residual stresses in a fiber/interphase/matrix system. Parametric studies showed that the tensile thermal residual stresses at the F/M interface were very sensitive to the CTE and thickness of the interphase layer. The modulus of the layer had only a moderate effect on tensile residual stresses. For a silicon carbide titanium aluminide composite, the tangential stresses were 20 to 30 pct. larger than the axial stresses, over a wide range of interphase layer properties, indicating a tendency to form radial matrix cracks during cooldown. Guidelines for the selection of appropriate material properties of the fiber coating were also derived in order to minimize thermal residual stresses in the matrix during fabrication.

Naik, R. A.↗