Combustion synthesis of SrTiO 3 using different raw materials

Abstract

This paper describes the combustion synthesis (CS) of SrTiO 3 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 TiO 2 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 SrTiO 3 together with very large propagation rate of combustion wave in the CS. More interestingly, the partial replacement of Ti by TiO 2 was not only feasible due to highly exothermic oxidation of Ti, but also most effective for purifying SrTiO 3 in the CS. This was probably because the TiO 2 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 SrTiO 3 by using reasonable-priced raw materials such as anatase is very attractive and practical for producing the high-grade SrTiO 3 powder.