Behavior of Ultrahigh-Temperature ZrB2-Based Ceramics in Oxidation
Ultrahigh-temperature ZrB2-based ceramics with different sintering additions was developed for extreme conditions. Its strength characteristics, phase composition, and structure were examined. The ceramics was oxidized in air at 1250 and 1550°C. In addition, the most stable composites were subjected to temperature cycling in a flow of aviation fuel combustion products in a temperature range of 1400–1500°C. All materials show high oxidation resistance. The method used to produce samples influences their oxidation behavior: materials produced by vacuum hot pressing show higher oxidation resistance than those produced by hot pressing in a CO–CO2 atmosphere, probably because of their higher final density. The best results were obtained when ZrB2 sintering was combined with introduction of MoSi2 and CrB2.