| 摘要 |
PURPOSE:To obtain SiC-coated graphite seal which is not liable to cause hair crack in SiC layer by converting the surface of an isotropic graphite base material having a bulk specific gravity of 1.50-1.70 and a coefficient of thermal expansion of 4.0X10<-6>/ deg.C into SiC. CONSTITUTION:Graphite base material is formed by kneading aggregate such as coke powder, graphite or the like with a binder such as tar pitch or the like, molding ground molding powder by C/P, and then burning same. A seal ring 1 is formed by the graphite base material, and the seal ring 1, silica powder and coke powder are put in a heating furnace to generate SiO gas. The SiO gas is brought into contact with the seal ring 1, so that the surface of the seal ring 1 is converted into SiC. Thus, SiC graphite seal which is not liable to cause hair crack can be obtained. |
