ELECTROCONDUCTIVE SILICON NITRIDE BASED COMPOSITE SINTERED BODY AND METHOD FOR PREPARATION THEREOF

摘要

An electroconductive silicon nitride based composite sintered body which has an average particle diameter of 100 nm or less and exhibits a surface roughness (Ra) after electric discharge machining of 0.3 mu m or less; and a method for preparing the electroconductive silicon nitride based composite sintered body which comprises pulverizing and mixing a silicon nitride powder and a metal powder until the silicon nitride powder has an average particle size of 30 nm or less, and then forming the resultant mixture, followed by sintering. The pulverizing and mixing step is preferably carried out until no X-ray diffraction peaks of the metal in the powder are visible. The composite sintered body is satisfactorily improved in the smoothness of a surface having been subjected to electric discharge machining and has excellent mechanical strength.