| 摘要 |
PROBLEM TO BE SOLVED: To obtain a fine texture of a double structure in which particles growing long distribute in the fine texture of silicon nitride by mixing the initial base stock of Si3 N4 having a specific particle size, prepared by applying the particle separation method, with a sintering additive, by compression-molding the mixture and sintering the molded product under normal pressure. SOLUTION: The Si3 N4 initial base stock powder that is prepared by applying the particle-separating method thereto and has particle sizes of <=0.5 μm, preferably 0.2-0.3 μm is mixed with a sintering additive, compression-molded to give a green compact. This green compact is sintered under normal pressure at a temperature of <=1,850 deg.C for several hours. For example, when it is sintered at 1,850 deg.C under normal pressure, if the powder of 0.5-0.6 μm particle sizes is used, the fine texture of the double structure does not appear, but the use of 0.2-0.3 μm particle size powder advents the double structure with improved fractional toughness whereby the distribution of columnar phase type particle in which uniform particles growing long can be obtained at a low temperature under normal pressure. |
