Microstructure Control of Barium Titanate – Potassium Niobate Solid Solution System Ceramics by MPB Engineering and their Piezoelectric Properties

Effect of the microstructural homogeneity of 0.5 BaTiO3 - 0.5 KNbO3 (0.5BT-0.5KN) solid solution ceramics on the dielectric and piezoelectric properties was investigated. Microstructure of a sample prepared by a conventional sintering method was homogenous, and the room temperature crystal structure was assigned to cubic Pm3m symmetry and therefore the sample was paraelectric. On the other hand, microstructure of samples prepared by a two-step sintering method was inhomogeneous, that is, it was made of BT and KN grains. The large electric field piezoelectric constant d33* increased with increasing interface area.