Oxidation Resistance of In Situ Reaction/Hot Pressing Synthesized Ti₂AlC–20% TiB₂ Composite at 600–900 °C in Air

The oxidation behavior and kinetics of Ti₂AlC–20vol.%TiB₂ composite at 600–900 °C in air were investigated. The results showed that the oxidation kinetics of the composite followed a logarithmic law within the given temperature range, which indicated that the composites had excellent oxidation resistance. The selective oxidation of Al in Ti₂AlC was greatly enhanced, which facilitated the formation of a continuous and dense protective layer of Al₂O₃. Meanwhile, the existence of molten B₂O₃ inhibited the outward diffusion of Ti and inward diffusion of oxygen, which prevented the growth of anatase TiO₂ at 600 °C and rutile TiO₂ at 700–900 °C. Therefore, the incorporation of TiB₂ completely inhibited the abnormally rapid oxidation of bulk Ti₂AlC at 600 °C and improved its oxidation resistance at 700–900 °C.