Solid state reaction studies in Fe3O4–TiO2 system by diffusion couple method

• The solid state reactions of Fe2O3-TiO2 system was studied by the diffusion couple method.
• Different products were formed by diffusion, and the FeTiO3 was more stable phase.
• The inter-diffusion coefficients and diffusion activation energy were estimated.

The solid state reactions in Fe3O4–TiO2 system has been studied by diffusion couple experiments at 1323–1473 K, in which the oxygen partial pressure was controlled by the CO–CO2 gas mixture. The XRD analysis was used to confirm the phases of the inter-compound, and the concentration profiles were determined by electron probe microanalysis (EPMA). Based on the concentration profile of Ti, the inter-diffusion coefficients in Fe3O4 phase, which were both temperature and concentration of Ti ions dependent, were calculated by the modified Boltzmann–Matano method. According to the relation between the thickness of diffusion layer and temperature, the diffusion coefficient of the Fe3O4–TiO2 system was obtained. According to the Arrhenius equation, the estimated diffusion activation energy was about 282.1 ± 18.8 kJ mol−1.