Abstract: A material for smoothing the outside surface of a woven fabric composite lay up in which a layered sandwich structure is formed of continuous fiber woven material, resin films and a mat of randomly oriented discontinuous fibers and the sandwiched layers are integrated into a single sheet of resin impregnated material by application of pressure and heat.

Abstract: A material for smoothing the outside surface of a woven fabric composite lay up in which a layered sandwich structure is formed of continuous fiber woven material, resin films and a mat of randomly oriented discontinuous fibers and the sandwiched layers are integrated into a single sheet of resin impregnated material by application of pressure and heat.

Abstract: The subject invention relates to a toughened epoxy matrix formulation useful as a prepreg for fiber reinforcements comprising at least two epoxy components, an amine hardener and about 10%-25% of a micropulverized polyimide thermoplastic having a molecular weight of from about 20,000 to about 100,000 and Tg of at least about 220.degree. C. The invention further relates to a process for preparing a toughened epoxy matrix formulation comprising:a. preheating a blend of at least two epoxy compounds to a temperature of about 130.degree. F. to about 140.degree. F.;b. blending into the epoxy blend from step (a) a micropulverized polyimide thermoplastic;c. mixing the blend of epoxy and thermoplastic at a temperature of about 110.degree. F. to about 130.degree. F.; andd. adding to the blend of epoxy and thermoplastic an amine hardener and mixing at about 110.degree. F. to about 130.degree. F. until a low mix viscosity is obtained.

Abstract: This invention relates to an improved pack mixture composition useful for the formation of a SiC pack cementation coating for protecting a carbonaceous substrate from degradation at temperatures above about 800.degree. F. comprising: Si from about 15% to about 50% by weight of the total composition; B up to about 25% by weight of the total composition when present; SiO.sub.2 from about 0.01% to about 3% by weight of the total composition; and SiC from about 40% to about 85% by weight of the total composition.The invention also relates to a method for protecting a carbonaceous substrate from degradation at temperatures above about 800.degree. F. comprising: preparing a pack mixture composition of from about 15% to about 50% Si, up to about 25% B, from about 0.01% to about 3% SiO.sub.

Abstract: This invention relates to an improved pack mixture composition useful for the formation of a SiC pack cementation coating for protecting a carbonaceous substrate from degradation at temperatures above about 800.degree. F. comprising: Si from about 15% to about 50% by weight of the total composition; B up to about 25% by weight of the total composition when present; SiO.sub.2 from about 0.01% to about 3% by weight of the total composition; and SiC from about 40% to about 85% by weight of the total composition and method thereof.The invention further relates to a cork release agent composition for providing the clean release of spent pack composition from a carbonaceous substrate.

Abstract: High tensile carbon fibers are provided with a high yield process in which, after oxidation of a precursor, the fibers are first precarbonized in an inert atmosphere to to about 600.degree. C. while imparting 5-10% stretch. In precarbonizing, the fibers are intially heated in a sweeping manner with substantial volumes of hot inert gas which is extracted along with products of decomposition before the fibers are cooled to a low, non-reactive exit temperature. The arrangement minimizes redeposition of tars on the fibers and stretches the fibers in a range in which substantial off-gassing occurs. Thereafter the fibers are finally carbonized at a higher temperature with a different tension being applied, to provide a more reliable less sensitive process that enables oxidation to be effected more rapidly.