| 摘要 |
PURPOSE:To manufacture a beta-type Si3N4 whisker compact excellent in bending strength and hardness, by blending specific amounts of powdered oxide of rare- earth elements or alkaline-earth metals with a powder of amorphous or alpha-type Si3N4 and sintering the resulting powder mixture in a low density under specific conditions. CONSTITUTION:A powder of oxide of rare-earth elements and/or alkaline-earth metals is blended by 0.1-20pts.wt. with 100pts.wt. of amorphous or alpha-type Si3N4 powder. The resulting powder mixture is filled into a crucible of required shape in 0.15-1.1g/cm<3> density. This filling is sintered under a nitrogen- containing nonoxidizing-gas atmosphere at 1,600-1,850 deg.C maximum temp. By this method, the beta-type Si3N4 whisker compact which has various characteristics of 0.15-1.1g/cm<3> compact density, >=25kg/cm<2> bending strength, >=45kg/cm<2> hardness, and >=30kg/cm<2> compressive strength and in which beta-Si3N4 whisker comprises >=90wt.% and whisker of 0.1-5mum diameter and 2-100mum length comprises >=80% of the above whisker and further the whiskers are in contact with each other and allowed to adhere to each other at a rate of one or more positions per piece of whisker can be obtained.
|
