MECHANISM OF THE HIGH-TEMPERATURE OXIDATION OF TITANIUM CARBIDE

High-temperature oxidation of titanium carbide in the temperature rang e of 600-1200 degrees C in air has been studied by TGA, XRD, SEM, and AES methods. Oxidation kinetics is multistage. The time intervals and temperature dependence of the rate constants of three parabolic and li near stages for oxidation at temperatures 900-1200 degrees C were dete rmined. According to SEM and XRD data, a two-layer scale was formed at temperatures exceeding 1000 degrees C. The outer scale consisted main ly of TiO2 (rutile). The inner scale consisted of various titanium oxi des. The effect of diffusion of both titanium and oxygen on the oxidat ion processes was studied. The mechanism of the oxidation process is d iscussed.