Synthesis of Composite Materials in the System Cr–Ti–B by the Self-Propagating High-Temperature Synthesis from Mixtures CaCrO4/TiO2/Al/B

Abstract

Using the method of self-propagating high-temperature synthesis (SHS metallurgy), cast composite materials were produced in the Cr–Ti–B system. The experiments were carried out in universal SHS reactors with an initial argon pressure of Рin = 5 MPa. Mixtures of CaCrO4, TiO2, Al, and B powders were used as batch. It was shown that by varying the mass ratio α of CaCrO4/2Al/2B and 3TiO2/4Al/6B mixtures in a batch, it is possible to significantly affect the synthesis patterns, phase composition, and microstructure of the target products. The initial mixtures are capable of burning in the range of α 0–20%. The phase separation limit occurs at α = 15%. The introduction of a highly exothermic CaO2 + Al additive into the mixture made it possible to expand the phase separation limit to α = 20%. As α increases, the amount of titanium boride in the final product increases. The resulting composite material consists of titanium-chromium boride distributed in a matrix of chromium boride. The synthesized materials were characterized by X-ray and local microstructural analysis. The structural phase states of the target products produced under various conditions were studied.