Low‐Temperature Synthesis of Bismuth Titanate by an Aqueous Sol–Gel Method

Abstract

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° and 432°C, and BIT began to crystallize before 450°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°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 Å, b =5.431 Å, and c =33.273 Å. 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°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.