Structure Phase Transition of Nanocrystalline Barium Titanate Doped with Lead Prepared by Sol-Gel Methods

Nanocrystalline (Ba,Pb)TiO3 (5 mol% Pb) with various grain sizes were prepared by a sol-gel process. The gain size, structure and phase properties of nanocrystalline BPT were studied by TEM, XRD and DSC. The results show that the structure phase transition is from ferroelectric tetragonal to paraelectric cubic phase and becomes more diffusive with decreasing particle size. On the other hand, the ferroelectric orthorhombic to ferroelectric tetragonal phase transition disappears with increasing particle size, it means that the formation of the unwanted orthorhombic phase of BaTiO3 is inhibited.