Structure and Properties of (Ba_(0.85)Ca_(0.15))(Ti_(0.9)Zr_(0.1-x)Sn_x)O_3 Lead-free Ceramics with High Piezoelectric Constant

Lead-free piezoelectric ceramics(Ba0.85Ca0.15)(Ti0.9Zr0.1-x Snx)O3(CBTZS-x) were prepared by the traditional solid state reaction. Phase structure, dielectric and piezoelectric properties for CBTZS-x samples with different Sn contents were investigated. It is found that all samples have a pure perovskite phase structure. With Sn content increase, the phase structure of CBTZS-x changes from coexistence of rhombohedral and tetragonal phase to tetragonal structure near room temperature. The phase change temperature of rhombohedral to tetragonal(TR-T) and Curie temperature(TC) shift towards lower temperature. When x=0.04, the TR-T is more close to room temperature, which shows excellent piezoelectric properties. The remnant polarization Pr and coercive field Ec are reduced, while dielectric constant er is improved by the modification of Sn. The CBTZS-x ceramic with x=0.04 exhibits the optimal properties: d33=665 pC/N, kp=55.6%, er=4520, Pr=12.5 μC/cm2 and Ec=1.6 kV/cm, which indicates that the CBTZS ceramic has a good application prospect.