Combustion synthesis of SrTiO3 using different raw materials

This paper describes the combustion synthesis (CS) of SrTiO3 using different raw materials, in which effects of size, shape and crystal structure of titanium source as a raw material on the purity of the combustion-synthesized product were mainly examined. In the experiments, different-shaped and -sized metallic Ti powder as fuel and different crystal-structured TiO2 as diluent were used as titanium source. The products of the CS were characterized by XRD and SEM-EDS analysis. As a result, the irregular shape of Ti powder less than 45 μm in size, having wider contacting area than the spherical one, was most suitable for producing SrTiO3 together with very large propagation rate of combustion wave in the CS. More interestingly, the partial replacement of Ti by TiO2 was not only feasible due to highly exothermic oxidation of Ti, but also most effective for purifying SrTiO3 in the CS. This was probably because the TiO2 addition released too strong exothermic reaction well. Specifically, as much as 40 mol% of the Ti powder could be substituted by rutile or anatase. This result suggested that the CS of SrTiO3 by using reasonable-priced raw materials such as anatase is very attractive and practical for producing the high-grade SrTiO3 powder.