Abstract: An oxidation resistant carbon-carbon composite (31) including a plurality of graphite fibers (13) within a carbonized (graphitized) matrix (14). A first material including boron (16) and a second material including silicon (18) are applied thereto. Heating the composite in the course of service use to a temperature at which the composite cracks enables the boron and silicon to combine to provide a borosilicate sealant of sufficiently low viscosity for sealing cracks in the composite.

Abstract: An oxidation resistant carbon-carbon composite (31) including a plurality of graphite fibers (13) within a carbonized (graphitized) matrix (14). A first material including boron (16) and a second material including silicon (18) are applied thereto. Heating the composite in the course of service use to a temperature at which the composite cracks enables the boron and silicon to combine to provide a borosilicate sealant of sufficiently low viscosity for sealing cracks in the composite.

Abstract: Carbon composite materials of increased resistance to oxidation are produced by heating a porous carbon composite material to an elevated temperature in a reaction chamber and introducing into said chamber a gas mixture comprising a decomposable boron-containing gas and a diluent and effecting deposition of boron as a solid on the walls of the pores of said composite as a consequence of said boron-containing gas decomposing.

Abstract: Fiber reinforced composite with five directions of fiber orientation comprising multiple planar fabric layers (16A, 16B, 16C, 16D) adjacent to each other with warp (W) and fill (F) fibers of one or more of such groups offset relative to the fibers of the others, a lateral array (extending perpendicular to the planes) of piercing fibers (5D) utilizing carbon/carbon, as reinforcement and matrix materials, providing a composite with tailored shear strength and stiffness in a selected anisotropy to meet the needs of specific thermostructural applications.

Abstract: The invention is directed to a transparent alumina material and a method of preparing this material.The material is characterized as a dense primary recrystallized polycrystalline structure having a degree of preferred crystal orientation. The material is transparent to visible and infrared light and quantitative values are given.The transparent alumina covered by this invention is made by means of hot forging and an annealing process for powders or dense compacts of high-purity alumina.

Abstract: A hot pressed composite structure, and method of making same are provided, wherein such structure is reinforced in three X, Y, and Z directions and comprises a matrix material, a plurality of straight elongate rigid reinforcing members embedded in the matrix material in spaced parallel relation and each disposed with its elongate dimension parallel to one of the above-mentioned directions, and a plurality of substantially straight elongate rigid reinforcing members embedded in the matrix material each with its elongate dimension disposed substantially along an associated one of the remaining two of the directions.

Abstract: A hot pressed composite structure, and method of making same are provided, wherein such structure is reinforced in three X, Y, and Z directions and comprises a matrix material, a plurality of straight elongate rigid reinforcing members embedded in the matrix material in spaced parallel relation and each disposed with its elongate dimension parallel to one of the above-mentioned directions, and a plurality of substantially straight elongate rigid reinforcing members embedded in the matrix material each with its elongate dimension disposed substantially along an associated one of the remaining two of the directions.

Abstract: The present invention is directed to an improved cutting tool blank formed by hot pressing a mixture of finely divided high-purity alumina and from about 0.05% to 0.35% of magnesia. Up to 0.10% nickel oxide may be present. The hot pressing temperatures are effected at a temperature in the range of about 1300.degree.C to 1525.degree.C so that the crystal size of the alumina in the tool blank has an average size range from 1 to 2 microns and the pressed blank has a final product density in excess of 3.97 grams per cubic centimeter. The preferred density of the blank is in excess of 3.98 grams per cubic centimeter. The hot pressing is conducted under vacuum conditions.