| 摘要 |
PURPOSE:To obtain a preliminarily sintered material having high relative density and formable with a direct hot hydrostatic press by preparing a slurry containing ceramic powder, silicon carbide whisker and silicon nitride whisker and having a viscosity lower than a specific level and forming the slurry while orienting the whiskers, CONSTITUTION:A slurry having a viscosity of <=3.0 poise is produced by dispersing ceramic powder and silicon carbide whisker or silicon nitride whisker in a solvent. The slurry is poured into a gypsum mold and molded while orienting the whiskers parallel to the wall surface of the gypsum mold to obtain a green molded article. Since the whiskers are free from mutual entanglement, the slurry is completely filled in the mold and the relative density of the green article reaches >=60%. The control of the orientation of the whisker can be carried out by adjusting the viscosity of the slurry within the above range. The green molded article is sintered under normal pressure to obtain a preliminarily sintered material having a relative density of >=95%. Since the preliminarily sintered material has high relative density, it can be sintered with a hot hydrostatic press without using a glass capsule. |
