Solid-state Reaction Studies in Al₂O₃–TiO₂ System by Diffusion Couple Method

Abstract

In order to study the formation mechanism of Al₂TiO₅, the solid-state inter-reaction between Al₂O₃ and TiO₂ under Ar atmosphere was investigated in the temperatures range from 1723 to 1873 K by the diffusion couple method. The phase of the inter-compound and the change of the concentration of Ti across the diffusion layers were confirmed by the electron probe microanalysis (EPMA). Based on the concentration profile of Ti element, the thickness of diffusion layers was obtained and the interdiffusion coefficients which were affected by temperature and concentration of Ti were calculated by the Wagner method. The experimental results indicate that the thickness of diffusion layers increases with the diffusion time. The magnitudes of interdiffusion coefficients were in the range of 10⁻¹⁰~10⁻¹² cm²/s and the range of diffusion activity energy E_D was from 266.77 kJ/mol to 309.96 kJ/mol.