Reactions in preparing Bi4Ti3O12 ultrafine powders by sol-gel process

Bismuth titanate powders around the nanometer range have been synthesized using sol-gel process with bismuth nitrate and titanium butoxide as raw materials. The formation mechanism of sol, gel and the reactions in heat treatment process have been studied. It was found that a chelate reaction occurred in solution. In heat treatment process, the gel started to crystallize into mixture phases at 400 degrees C; at 700 degrees C, formed four phases, at 850 degrees C, finally transformed to single layered perovskite structure. The particle size of powders increased with calcination temperature.