Oxidation processes in glass-ceramic composites based on titanium boride

The reaction formation of TiB2-and SiO2-based composite materials and coatings upon heat treatment of initial components in air is investigated. It is shown that the glass melt formed in the course of the chemical reaction encapsulates titanium boride particles, thus imparting the 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 graphite during their heat treatment is studied using gravimetric, differential thermal, and X-ray powder diffraction analyses. The phase compositions of the surface layers 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.