Abstract: A carbon composite material reinforced with a carbon fiber and an inorganic fiber. The composite material has a core formed of a carbon fiber-reinforced carbon composite comprising a carbon fiber reinforcement and a carbon matrix, The core is externally covered with an inorganic fiber-reinforced carbon composite comprising an inorganic fiber reinforcement, other than carbon, and a matrix composed either of carbon alone or a mixture of carbon and boride. This provides for sound and steady protection against oxidation, as well as for retention of high strength in an oxidizing atmosphere at high temperatures.

Abstract: The invention relates to a press cylinder for a high-temperature, high-pressure pressing machine for use in sinter molding ceramics, hard metals, and the like. An outer casing constructed of a carbon fiber reinforced carbon composite and an inner casing constructed of a heat resistant material are fitted together. The inner casing is formed with a longitudinally extending slit which meets given conditions. A gap which meets given conditions is formed between the outer casing and the inner casing. Because of the presence of the slit and the gap, no substantial stress is liable to be exerted on the outer and inner casings which are different in thermal expansion coefficient. Therefore, the outer and inner casing are not liable to fracture or plastic deformation.