Oxidation behavior of boron-containing (Zr,Ti)C _x B _y solid solution ceramics at 1600 °C in air

Abstract

Multicomponent boron-containing carbide coatings (i.e., (Zr,Ti)C x B y ) on a C/C composite show good ablation resistance. However, the high-temperature oxidation behavior of this new type of boron-containing (Zr,Ti)C x B y solid solution ceramics has not been clarified yet. The present work fabricated (Zr,Ti)C x B y solid solution block ceramics by spark plasma sintering, and their oxidation behavior at 1600 ℃ in air (N 2 -20-vol% O 2 ) was investigated for the first time. The effects of boron on the oxidation resistance of (Zr,Ti)C x B y ceramics were examined. The results indicate that the (Zr,Ti)C x B y ceramics display good oxidation resistance with the parabolic rate law describing the oxidation process. After the trace solution of boron (0.5 wt%) into (Zr,Ti)C x , the oxidation resistance of carbide ceramics is significantly enhanced, leading to a decrease of 30% in the oxidation rate constant. The formed oxide scale in the (Zr,Ti)C x B y ceramics is dense, and the interlayer shows stronger ability to inhibit inward diffusion of oxygen. In addition, the introduction of boron leads to more negative binding energy of (Zr,Ti)C x B y and improves the oxidation resistance of carbides.