Oxidation experiments were conducted on Ti3Al at 1023 to 1273K in a one-atmosphere pure oxygen environment. The oxidation products were analyzed using the scanning electron microscope, energy-dispersive spectrometer and X-ray diffraction 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 was found to be 295.43kJ/mol, and the frequency factor, D0, was calculated to be 0.68m2/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.

Interdiffusion in the TiO2 Oxidation Product of Ti3Al. Reddy, R.G., Wen, X., Okafor, I.C.I.: Metallurgical and Materials Transactions A, 2001, 32[3], 491-5