High-temperature oxidation behavior and mechanism of W-doped (TaHfTi)C solid solution ceramics

(TaHfTi)C solid solution ceramics doped with 0-40 mol% W are prepared using spark plasma sintering (SPS). Isothermal oxidation tests are conducted on W-doped ceramics at 800-1200°C. The high-temperature oxidation behavior and mechanism of W-doped (TaHfTi)C solid solution ceramics at 800-1200°C are investigated. The oxidation kinetics of the three ceramics follow the parabolic law, with the oxidation rate constant increasing in the order: W0> W20> W40, indicating a dependence of oxidation resistance on W content. During oxidation, a dense protective oxide layer forms on the W-doped ceramics, composed of multicomponent complex oxides such as Ta 8 W 9 O 47 , Hf 6 Ta 2 O 17 , and HfTiO 4 . The W40 specimen exhibits the highest oxidation resistance, which can be attributed to the formation of a dense network structure created by the outward diffusion of Ti- and Hf-containing oxides and the inward diffusion of oxygen, effectively preventing further oxidation of the substrate.