Structure and enhanced piezoelectric performance of BiScO3-PbTiO3-Pb(Ni1/3Nb2/3)O3 ternary high temperature piezoelectric ceramics

Abstract

BiScO3-PbTiO3 based solid solutions are the most promising candidates in high temperature piezoelectric application field. In this research, (1-x-y)BiScO3-xPbTiO3-yPb(Ni1/3Nb2/3)O3 (BS-xPT-yPNN) ternary high temperature piezoelectric ceramics have been prepared by the traditional solid-state reaction methods and investigated in detail. X-Ray diffraction analysis shows that the system has a pure perovskite structure and the morphotropic phase boundary (MPB) region shifts to the low PT region with the increasing PNN end member. The room temperature phase diagram has been drawn to predict the MPB region and search for the optimal electrical properties of the BS-xPT-yPNN ternary solid solutions. The dielectric temperature spectra present typical diffuse phase transition characteristic caused by the production of chemical heterogeneities with the introduction of PNN. For the BS-xPT-0.025PNN system, the optimal properties of the piezoelectric coefficient d33 522 pC/N, planar electromechanical coupling factor kp 59.6%, remnant polarization Pr 39.2 μC/cm2, and the Curie temperature Tc 400 °C are obtained for the BS-0.61PT-0.025PNN composition. Furthermore, the piezoelectric performance declines a little to 495 pC/N and 59% of the BS-0.60PT-0.05PNN composition with the increase of PNN content, which is also equivalent to that of the unmodified BS-PT and other modified BS-PT such as the BS-PT-PZN system. All these properties reveal that the BS-xPT-yPNN ceramics constitute a new family of high performance high temperatures piezoelectric materials.