Piezoelectric and dielectric properties in grain oriented (Bi0.5Na0.5)TiO3-BaTiO3 ceramics

The objective of the present study is to investigate the effect of grain growth process method on characteristics of a lead-free piezoelectric ceramics, 0.945(Bi0.5Na0.5)TiO3-0.055BaTiO(3) (hereafter 0.945BNT-0.055BT). One ceramic material of Bi-based perovskite structure family, (Bi0.5Na0.5)TiO3-BaTiO3, was chosen as a matrix material and SrTiO3 platelet as a template. To improve the densification on templated grain growth method, hot pressing method was combined with the templated grain growth. Specimen processed by templated grain growth and hot pressing methods exhibited a high piezoelectric coefficient d(31) of -79.6 pC/N and an electromechanical coefficient, k(31) of 0.35. over the other specimens, fabricated by solid reaction and templated grain growth, respectively. This enhanced properties were attributed to the densification of ceramic matrix due to reduction of pore existing during abnormal grain growth from the SrTO3 template and its resultant heterogeneous shrinkage.