Abstract: This invention discloses a method for subjecting a carbon/carbon composite material to strain at high temperature which permits the resulting composite material to be formed into various shapes.

Abstract: A novel method is disclosed for producing specular surfaces, composed of pure carbon, on carbon-carbon composites of arbitrary weave configuration. The method utilizes a thin sheet of fine grained polycrystalline graphite as a stress-isolating interlayer between the composite substrate and the specular surface layer. The interlayer is bonded to the carbon-carbon substrate with a high char yield carbonizable adhesive. An outer layer of glassy carbon is then applied using a high char yield resin solution or (lacquer). The resulting assembly is then carbonized to convert all uncarbonized polymer to carbon. The interlayer prevents the propagation of the substrate carbon-carbon composite's crack structure to the glossy carbonized polymer surface thus formed, resulting in a high degree of specularity and zero gas permeability.

Abstract: An oxidation process for stabilization of pitch-based matrices in the fabrication of carbon-carbon composites. By oxidizing a fiber preform impregnated with petroleum-derived mesophase pitch at temperatures in the range of 190.degree. to 300.degree. C. for periods of the order of ten hours, the matrix is fixed in place within the preform so that softening, bloating, and expulsion of the matrix are avoided when the body is carbonized. The invention can also be practiced to increase the carbon yield upon carbonization. Sufficient access porosity must exist in the matrix to permit oxidation throughout the composite body; this is normally formed in a preform due to the mismatch in thermal expansivities of fiber and matrix. Also, the softening point of the pitch must be above the oxidation temperature; this need can be met for most mesophase pitches.

Abstract: A technique for impregnating a fluid so that the impregnated fluid retains information about the highest pressure that has ever been exerted on it. This technique is particularly useful where normal pressure measurement methods are not practical.