Synthesis of Low Loss Lead Free Piezoelectric BNT-BT Ceramic

Oxide materials with perovskite structure having the general formula $ABO_3$, form the backbone of the ferroelectrics industry. For a long time, ferroelectric materials have come into widespread use in applications that range in sophistication from medical ultrasound and underwater sonar systems, smoke detector buzzers to novel applications in active and passive damping systems for sporting goods and automobile and aerospace sectors. However, an attention has been focused across the globe to find out new environment-friendly lead-free ferroelectric materials. The $(Bi0.5Na0.5)TiO_3$ (BNT) based composition is reported as the promising for piezoelectric applications. Application of BNT into practical devices has been hindered by leakage problems that lead to low resistivity. In order to reduce the problems mentioned here, the method of forming binary solid solutions with other perovskites with good dielectric properties was adopted. The present work deals with the synthesis, densification and characterization of (1-x) $(Bi0.5Na0.5)TiO_3$ $(BNT)- x BaTiO_3(BT)$ solid solution (where x=0, 0.06). Solid state synthesis method and autocombustion technique have been adopted to synthesize phase pure powder. Phase pure BNT- BT powder can be prepared at a temperature as low as 600oC by auto-combustion route. It is very difficult to prepare phase pure solid solution system by conventional solid state synthesis method. 96% of theoretical density was achieved for combustion synthesized powder