Abstract

Nanocrystalline strontium titanate (SrTiO₃, ST) powders were prepared by sol-gel combustion method. The influence of fuel content ratio (ratio of citric acid (CA) and total metal nitrate (MN); Ra = CA:MN) and calcination temperature were investigated on the structure, morphology, and crystallite size by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicate that the Ra ratio of 3:1 is adequate for a good crystallization of pure perovskite phase after calcination by combining the washing process with nanometric crystallite size and porous microstructure. For the SrTiO₃ powder synthesized with Ra ratio = 3:1, the effect of calcination temperature was investigated, showing that the perovskite structure is optimum crystallized at 500°C, without secondary phase formation. The particle sizes increased with increasing Ra ratio and calcination temperature.

Key words: Sol-gel combustion method, strontium titanate and fuel content ratio, nanocrystalline powders.