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

Abstract

Multicomponent boron-containing carbide coatings (i.e., (Zr,Ti)CxBy) on a C/C composite show good ablation resistance. However, the high-temperature oxidation behavior of this new type of boron-containing (Zr,Ti)CxBy solid solution ceramics has not been clarified yet. The present work fabricated (Zr,Ti)CxBy solid solution block ceramics by spark plasma sintering, and their oxidation behavior at 1600 ℃ in air (N2–20-vol% O2) was investigated for the first time. The effects of boron on the oxidation resistance of (Zr,Ti)CxBy ceramics were examined. The results indicate that the (Zr,Ti)CxBy 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)Cx, 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)CxBy 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)CxBy and improves the oxidation resistance of carbides.

Keywords

• ultra-high-temperature ceramics (uhtcs)
• (zr,ti)cxby solid solution
• oxidation behavior
• oxidation resistance