THE FORMATION AND REACTIVITY OF SOME NONMETAL SILICIDES

Abstract

Boron silicides, B₄Si and B₆Si, have been produced by calcining mixtures of finely-divided boron and silicon at different temperatures and information obtained regarding the process mechanism. There are optimum reaction times for the formation of B₄Si, before it disproportionates into B₆Si and Si. The atmospheric oxidation of boron silicides is retarded by the product layers of boric oxide, B₂O₃, and silica, SiO₂, and also by their mineralising action promoting sintering of the material. Boron silicides may be used only in an oxidising environment at lower temperatures (500 - 800°C) without severe degradation occurring if they have been first subjected to oxidation at higher temperatures (ca. 1000°C) in order to form a protective coating.

Date of Award	1973
Original language	English
Awarding Institution	University of Plymouth