Interdiffusion in the TiO2 oxidation product of Ti3Al

Oxidation experiments have been conducted on Ti₃Al in the temperature range 1023 to 1273 K in a one-atmosphere pure oxygen environment. The oxidation products were analyzed using the scanning electron microscope (SEM), energy-dispersive spectrometer (EDS), and X-ray diffraction (XRD) techniques and found to be predominantly TiO₂ (rutile). The oxidation rate was observed to obey the parabolic rate law. Diffusivity data were obtained using the parabolic rate constant for interdiffusion of Ti and O in the oxide layer. Parabolic rate constants were calculated from oxidation rate data, and Valenci equations for flat sheets were used to calculate diffusion coefficients. The activation energy, Q, was found to be 295.43±5.90 kJ/mol, and the frequency factor, D ₀, was calculated to be 0.68±0.01 m²/s for oxygen in the TiO₂. The activation energy obtained in this study matches closely with that of oxygen diffusion in TiO₂ reported in the literature.