Kinetics of strontium titanate formation from solid state reaction between strontium carbonate and anatase

The kinetics of SrTiO3 formation from equimolar SrCO3 and TiO2 (anatase) at the temperature range from 1021K to 1207 K in argon atmosphere was studied. The fractional conversion was determined from the content of SrTiO3 using X-ray diffraction quantitative analysis. The data obtained were fitted to various equations commonly used in kinetic analysis of isothermal solid state reactions. The microstructure of the sample after high temperature calcination was characterized by using scanning electron microscope (SEM).and transmission electron microscope (TEM). In the temperature range from 1061 K to 1207 K, it has been found that the reaction kinetics, in the order of preference, could be described satisfactorily by Ginstling-Brounshtein model and Carter model. The apparent activation energy evaluated on the basis of each model was 271 and 268 kJ/mol respectively. The overall rate of the reaction was contrRiled by the diffusion step of Sr2+, ions through the SrTiO3 layer. However, in the temperature range from 1021K to 1061 K the reaction exhibits a tendency to alter the rate controlling step from the diffusion to nucleation process of the strontium titanate.