Isotropic hexagonal boron nitride article prodn. - by sintering green body without mechanical pressure application

摘要

Prodn. of a polycrystalline article with an isotropic microstructure based on hexagonal boron nitride with a boron nitride content of at least 80% involves (a) pre-compacting a powder mixt. contg. boron nitride powder and a sintering aid to a green body of at least 50% theoretical density, and (b) sintering, without mechanical pressure application, at max. 2400 deg.C to at least 55% theoretical density, the article undergoing no vol. increase during sintering. USE/ADVANTAGE - The article is useful in electronics, in the steel industry (esp. in horizontal continuous casting and near-net shape casting) and as a crucible material. The process allows prodn. of a boron nitride article with an isotropic microstructure without use of mechanical pressure during sintering.