| 摘要 |
PURPOSE:To improve fracture toughness value, thermal shock resistance, etc., by uniformly making a given amount or more of very small crack voids of specific shape exist in an interface between pillar-shaped silicon nitride particles and a grain boundary phase in a sintered compact of siliceous nitride. CONSTITUTION:Silicon nitride powder is mixed with a sintering auxiliary (e.g. Y2O3), molded, primarily sintered at a high temperature of 1,700 deg.C or higher in a nitrogen atmosphere under 10 atmospheric pressure or lower and secondarily sintered under 10 atmospheric pressure or higher in a nitrogen atmosphere at 1,600 deg.C or higher. Consequently, a sintered compact of siliceous nitride consisting of the sintering auxiliary and Si3N4 or sialon particles, which is a sintered compact of siliceous nitride approximately uniformly contains 5,000 or more very small crack voids/mm<2> having 3mum or shorter width, 0.5-20mum length and at least one corner with 0.5mum or shorter curvature radius in the interface between pillar-shaped silicon nitride particles and a grain boundary phase, is obtained. |
