| 摘要 |
PURPOSE:To provide a silicon nitride sintered body tool excellent in toughness as well as a wear resistance and high in a wear resistance even in a pratical use. CONSTITUTION:A feature of this silicon nitride sintered body tool is that crystal grains of the silicon nitride sintered body consist of 50-90 volume % of a columnar crystal group whose minor axis diameter is 1.0mum or less and 5-30 volume % of a columnar crystal group whose minor axis diameter is 1.5mum or more. Raw powder produced by means of an imide decomposition method, metallic Si direct nitriding method, silica reduction method and the like is used, and a press-molded body thereof, after mixing and granulation, is subjected to nitrogen gas pressure sintering at 1700-1900 deg.C and at 1-300atm. or after this nitrogen gas pressure sintering is subjected to an HIP under a condition of nitrogen gas pressure 10-3000atm. for manufacturing. |
