| 摘要 |
PURPOSE:To develop a rolling bearing sufficiently usable in a wide temperature range from room temperature to high temperature by using material obtained by pressure- molding, and sintering complex raw material composed of boron carbide and mesophase carbon sphaerites. CONSTITUTION:B4C powder used mainly as boron carbide is mixed with carbon material and made into a complex by high temperature baking after being molded. An optically anisotropic carbonaceous globule known also as the name of a mesophase carbon sphaerite is globular and manufactured by pitch heat treatment. Pulverization is performed by shock, abrasion, jet grinding, or the like. The mixed powder is molded by a hydraulic press or the like, and the molded body is subjected to temperature rise in coke breeze under the non-oxidizing gas atmosphere. After removing the volatile part, the molded body is cooled under the non-oxidizing gas atmosphere so as to be formed into a pre-burned product, and the pre-burned product is subjected to heat treatment under the inactive gas atmosphere or under reduced pressure to become a burned body. The thus obtained carbon-boron carbide sintered body is of high strength and also excellent in heat resistant impulse, oxidation resistance and machinability. |
