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OwnerJames C. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Fletcher, Leroy Honeycutt, III +1inventors
InventorsJames C. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Fletcher, Leroy Honeycutt, III, Charles R. Manning, Jr.
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Ceramic tantalum carbide artifacts having high thermal shock and mechanical erosion resistance are provided by incorporating tungsten-rhenium and carbon particles in a tantalum carbide matrix. The mix is sintered by hot pressing to form the ceramic article which has a high fracture strength relative to its elastic modulus and thus has an improved thermal shock and mechanical erosion resistance. The tantalum carbide is preferable less than minus 100 mesh, the carbon particles are preferable less than minus 100 mesh, and the tungsten-rhenium particles are preferable elongate, having a length to thickness ratio of at least 2/1. Tungsten-rhenium wire pieces are suitable as well as graphite particles.
A ceramic artifact adaptable for use in throat areas of rocket nozzles and the like which consists of a hot-pressed composite of at least 80 to 85 percent of theoretical density of a tantalum carbide matrix and from one to five percent by weight, based on the weight of the article, of particles of a metal selected from the group consisting of tungsten and tungsten-rhenium alloy, and from one to three percent by weight based on the weight of the article, of carbon or graphite particles and wherein the tantalum carbide matrix is formed from the group consisting of reactor grade and commercial grade particles.
A method of making a ceramic article having high resistance to thermal shock comprising the steps of providing a mixture of particles of commercial grade tantalum carbide, from one to five percent by weight of a metal selected from the group consisting of tungsten and tungsten-rhenium alloy, and from one to three percent by weight of carbon or graphite particles and hot pressing the mixture in the temperature range of from 1700.degree. C. to 2150.degree. C. and at a pressure sufficient to produce an article of at least 80 to 85 percent of theoretical density.
Dependencies are inferred from the claim text.