Solid state reactions in the Fe3O4-TiO2 system were studied using diffusion couple experiments at 1323 to 1473K, in which the oxygen partial pressure was controlled by the CO-CO2 gas mixture. XRD analysis was used to confirm the phases of the inter-compound, and the concentration profiles were determined by electron probe micro-analysis. Based upon the concentration profile of Ti, the interdiffusion coefficients in the Fe3O4 phase, which were both temperature and Ti ion concentration dependent, were calculated by using the modified Boltzmann-Matano method. According to the relationship between the thickness of the 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 282.1kJ/mol.

Solid State Reaction Studies in Fe3O4-TiO2 System by Diffusion Couple Method. Ren, Z., Hu, X., Xue, X., Chou, K.: Journal of Alloys and Compounds, 2013, 580, 182-6