Characterization of Bi4Ti3O12 powder prepared by the citrate and oxalate coprecipitation processes

Bismuth titanate (Bi4Ti3O12) powder was prepared by citrate and oxalate coprecipitation of bismuth nitrate pentahydrate, Bi(NO3)3·5H2O and titanium butoxide, Ti(OC4H9)4. The intermediate products with 500–1000 °C calcination were characterized using the XRD. At low temperature, Bi4Ti3O12 powder and some impurities were detected. At 1000 °C, the purified powder was obtained. At 700 °C and above, the powder underwent a phase transformation from tetragonal to orthorhombic. By using the TGA, the intermediates prepared by the citrate and oxalate coprecipitation processes were the citrate salt and the oxalate–hydroxide mixture, respectively. The FTIR analysis showed the TiO stretching in the 811–816 and 574–584 cm−1. The morphologies shown by the SEM micrographs were consistent with the XRD patterns.