SILICON NITRIDE-BASED SINTERED COMPACT

摘要

PURPOSE:To provide a silicon nitride sintered compact, having excellent mechanical characteristics especially at ordinary temperature and advantageous to productivity and cost. CONSTITUTION:The objective silicon nitride sintered compact is characterized as follows. The sintered compact is composed of beta-silicon nitride (containing beta'-sialon) as a silicon nitride-based crystal phase substantially identified by X-ray diffractometry. The prismatic type silicon nitride crystal grains having 2.0-5.0mum average major axis grain diameter observed in an optional two- dimensional cross section in the sintered compact accounts for >=5% to <=30% expressed in terms of area ratio and the remainder is composed of hexagonal or granular silicon nitride crystal grains and grain boundary phase having <=1.0mum average grain diameter.