| 摘要 |
PURPOSE:To obtain a silicon nitride sintered body hardly reducing the high temp. strength by removing a silica film incorporated in a silicon nitride molded body in heating in a furnace immediately before sintering and then sintering the molded body in the same furnace. CONSTITUTION:When a molded body consisting of silicon nitride powder with a silica film formed on at least the surface and a sintering aid or silicon carbide powder is sintered, the silica film is removed in heating in a furnace immediately before sintering and then the molded body is sintered in the same furnace. In the furnace, the partial pressure of gaseous nitrogen in the nonoxidizing atmospheric gas is controlled under reduced or elevated pressure and the gas is preferably allowed to flow to the entire surface of the body to be treated. |
