Effect of Contents on the Electrical and Piezoelectric Properties of (1 − x)(Bi, Na)TiO(3)–x(Ba, Sr)TiO(3) Lead-Free Piezoelectric Ceramics

In this study, the composition of lead-free piezoelectric ceramics (1 − x)(Bi(0.5)Na(0.5))TiO(3)–x(Ba(0.5)Sr(0.5))TiO(3) with excellent piezoelectric properties was investigated. Crystal analysis and electrical and piezoelectric properties were analyzed according to the content of the BST composition. A phase change from rhombohedral to tetragonal structure was observed in 0.12 BST, and the densest and most uniform microstructure was confirmed in this composition. The dielectric constant increased from 905 to 1692 as the composition of BST increased to 0.12 BST. Afterward, as the composition of BST increased, the permittivity tended to decrease. Additionally, at 0.12 BST, P(r) was the highest at 23.34 μC/cm(2). The piezoelectric charge constant (d(33)) and the electromechanical coupling coefficient (k(p)) were 152 pC/N and 0.37, respectively, and showed the highest values at 0.12 BST. Curie temperature (T(m)) was analyzed 242 °C at 0.12 BST, the optimal composition. It was confirmed that the characteristics of 0.12 BST were excellent in all conditions. Therefore, it was confirmed that 0.12 BST is the optimal composition for (1 − x)BNT–xBST piezoelectric ceramics.