Synthesis, heat resistance, and optical properties of boron silicide and materials based on it

Conditions of synthesis from elements of pure superfine powder of boron silicide B^sub 4^Si are investigated. It is shown that the silicide phase forms on boron particles and B^sub 4^Si particles inherit the shape and size of initial boron particles, which makes it possible to control the particle size of the powder obtained. The oxidation of pure boron silicide and materials based on it in air and their optical properties are studied. It is shown that chromium diboride added to boron silicide increases the oxidation resistance of B^sub 4^Si and hardly decreases its absorbance. The B^sub 4^Si-CrB^sub 2^ material can be successfully introduced into the compositions of heat-protective coatings operating in air at 1300 °C.[PUBLICATION ABSTRACT]