Formation of SrTiO3 from Sr-oxalate and TiO2

Abstract SrTiO 3 powder has been prepared from Sr-oxalate and TiO 2 precursors, instead of using titanyl-oxalate. Sr-oxalate was precipitated from nitrate solution onto the surface of suspended TiO 2 powders. Crystallization of SrTiO 3 from the precursor was investigated by TGA, DTA and XRD analysis. It is evident that precursor, upon heating, dehydrates in two stages, may be due to the presence of two different types of Sr-oxalate hydrates. Dehydrated precursor then decomposes into SrCO 3 and TiO 2 mixture. Decomposition of SrCO 3 and simultaneous SrTiO 3 formation occur at much lower temperature, from 800 °C onwards, due to the fine particle size of the SrCO 3 and presence of acidic TiO 2 in the mixture. The precursor completely transforms into SrTiO 3 at 1100 °C. About 90 nm size SrTiO 3 crystallites are produced at 1100 °C/1 h, due to the lower calcination temperature and better homogeneity of the precursor.