Abstract: Layered carbon-carbon composites having improved interlaminar tensile strength are disclosed together with a process for making such composites. A metal catalyst is first deposited on a panel comprising a plurality of layers of carbon fiber cloth. The panel is then exposed to a gaseous hydrocarbon in an inert atmosphere at elevated temperature in order to promote the growth of graphite whiskers between the carbon cloth layers.

Abstract: Method of forming a hollow, carbon/carbon composite article around an axis of symmetry, in which method a heat refractory mandrel is shaped to provide a desired inner surface configuration and tolerances of the article, and one or more plies of thermally stable carbon filaments are braided over the surface of the mandrel. The filaments have a diameter of substantially not greater than about 6 microns and a modulus of elasticity of substantially not less than about 45.times.10.sup.6 psi. The plies are then impregnated with a carbonizable liquid impregnant, and the assembly of impregnated plies and mandrel is heat treated so as to carbonize the impregnant. The resulting composite article has a high translation of the original strength of the filaments and has an inner surface defined by the outer surface of the mandrel.

Abstract: A novel process is provided for the formation of improved carbonized fibrous materials with increased modulus of elasticity and strength as well as decreased diameter. Preferably, the precursor material is acrylonitrile, typically copolymerized with a minor amount of an acrylic monomer such as methyl acrylate. Drawing of the polymer fiber during oxidation is effected at an elevated temperature in the presence of a carboxylic acid (other than formic acid), or its anhydride, within the fiber. It is believed that the acid and/or its anhydride which is formed at the oxidizing temperature serves as a plasticizer and reduces the fiber yield stress and increases fiber plasticity so that the fibers may be drawn by as much as 300% or more in the presence of the acid and/or its anhydride during oxidation, thereby providing the desired improvement in increased modulus of elasticity and tensile strength of carbon fibers formed subsequently by carbonization of the oxidized fibers.