Abstract: A thermomechanical pressing ("TMP") method for obtaining rapidly a high density (1.2 g/cm.sup.3 or higher) carbon/carbon composite preform from any carbon fiber including PAN-based carbon fibers and industrial coal-tar or petroleum pitches (including synthetic derivatives) having a melting point m.p.=80-350.degree. C. Green preforms may be prepared from mixtures of carbon fibers and pitch, and the resulting mixture is formed to impart a cylindrical shape to the green preform. The green preform is charged into a metallic mold where it is heated, stabilized, pressurized for a period of time, and cooled.

Abstract: The invention relates to a heat-insulating structural carbon material and the process for producing thereof. This heat-insulating structural material is prepared from a suspension of discrete carbon fibers in a viscoplastic liquid such as polyglycol, glycerine and petroleum oils, by molding a preform and orienting discrete filaments, followed by baking the preform and depositing pyrolytic carbon in the porous structure thereof. This heat-insulating material comprises a coke matrix, discrete carbon filaments, the coke matrix as a porous film-like structure of coke residue on said filaments, and pyrolytic carbon.

Abstract: The invention relates to a process for obtaining refractory antioxidative coatings on carbon-based materials and articles operating in an oxidizing environment at temperatures of up to 2000.degree. C. under thermal cycling and high-speed gas stream conditions. The process comprises the heat-treatment of the surface to be protected in silicon vapors and is characterized in that prior to said silicon vapor treatment, the surface to be protected is covered with a layer of the composition consisting of HfB.sub.2 +C powdery filler and a carboxymethyl cellulose-based binder, followed by drying under normal conditions till it is completely dry. The process is intended for oxidation protection of structural elements and articles in metallurgy, aircraft, and other industries.