Nanotechnology for Encapsulating Zirconium Boride upon Formation of Heat-Resistant Coatings

The reaction formation of ZrB2- and SiO2-based composite materials and coatings upon heat treatment of the initial components in open air is investigated. It is shown that the glass melt formed in the course of the chemical reaction encapsulates zirconium boride particles, thus imparting high-temperature strength to the composite material. The influence of the concentration and sizes (down to a nanometer scale) of silica particles on the kinetics of oxidation of the compact samples and coated materials during their formation and heat resistance tests is studied using gravimetric, differential thermal, X-ray powder diffraction, and chemical analyses, as well as electron probe X-ray microanalysis. The structure and phase composition of the surface and the bulk of the samples are determined. The compositions of coatings that ensure effective protection of graphite from oxidation in air at high temperatures are proposed.