SiC and Si₃N₄ sintered bodies with new borodiphenylsiloxane polymers as binder

Abstract

HIGH-STRENGTH SiC and Si₃N₄ sintered bodies have been studied for their application as high-temperature structural materials¹. A high-strength SiC sintered body using an organometallic polymer as the binder has been reported². A feature of this method is that polycarbosilane (PC) as the binder is converted into fine-particle inorganic β-SiC by heat-treatment, which fills the grain boundaries of the matrix SiC. In this way, with a hard-to-sinter material such as SiC or Si₃N₄, a sintered body with excellent mechanical strength can be produced at relatively low temperature without using a hot press. We recently synthesised a particular form of polyborodiphenylsiloxane (PB)p, an organometallic polymer, which is very effective as a binder. Using this binder, SiC and Si₃N₄ sintered bodies of high mechanical strengths could be successfully obtained. These results are outlined here.