Preparation of barium/strontium titanate by solution route

As compared to the conventional solid-state route, solution routes have been reported to produce powders with better homogeneity and controlled morphology. A new solution-based method has been developed to produce fine powders of BaTiO 3 and SrTiO 3 of high reactivity. In this method an equimolar mixture of solutions of barium nitrate or strontium nitrate and titanium nitrate is heated with suitable amount of glycerol under controlled conditions to get a pasty mass, which was dried at 200†C and calcined at 500†C to get precursor powder, free from organic matter. On further heating the material transforms into single phase BaTiO 3 or SrTiO 3 having surface area of 6-8 m 2 /g. The pellets obtained by cold-pressing this powder, could be easily densified to 98% T.D. after sintering at 1250†C for a short duration. Phase analysis was done by X-ray diffraction. Thermogravimetry (TG) and Differential Thermal Analysis (DTA) experiments were done for the 200†C dried powder. The relative permittivity of the sintered BaTiO 3 pellets was measured at different temperatures using an LCR bridge. The powder morphology and the particle size distribution were studied by scanning electron microscopy.