| 摘要 |
PURPOSE:To improve mechanical strength and toughness by molding a powdery mixture of Si3N4 with the oxide of a rare earth element, NgO and a specified silicide and sintering the molded body in an atmosphere contg. gaseous nitrogen. CONSTITUTION:Si3N4 of <=5mum average particle size is mixed with 1-15wt.% oxides of one or more kinds of rare earth elements such as Y2O3, 1-8wt.% MgO, 0.1-3wt.% at least one of TiSi2 and ZrSi2 and a solvent such as acetone and this mixture is molded under 10-100 MPs uniaxial molding pressure or 150-700 MPa biaxial isostatic press molding pressure to obtain a molded body. This molded body is sintered at 1,500-2,000 deg.C in an atmosphere contg. gaseous nitrogen under the critical decomposition pressure of Si3N4 or above. |
