Low-temperature synthesis of bismuth titanate by an aqueous sol-gel method

Homogeneous and fine bismuth titanate (BIT) nanoplate-like powders were synthesized by a modified and simple sol-gel method. The thermal gravimetry-differential thermal analysis-derivative differential thermal analysis indicated that BIT gel decomposes in two steps posited at approximately 278 degrees and 432 degrees C, and BIT began to crystallize before 450 degrees C. Based on the high-temperature X-ray diffraction results, it was concluded that the crystallization temperature of BIT synthesized by the present method was about 425 degrees C and there was no evidence of the formation of an intermediate phase. The BIT crystal structure belonged to the orthorhombic phase with lattice parameters a=5.420 angstrom, b=5.431 angstrom, and c=33.273 angstrom. Field emission-scanning electron microscopy revealed that fine and uniform BIT nanoplate-like powders, about 30 nm in size, were obtained after sintering at 500 degrees C. With increasing temperature, the BIT grains rapidly grew and the coalescence of adjacent grains took place. The synthesis temperatures adopted were substantially lower than those reported in the other literatures.