Electromechanical Properties And Stability Of High Power Based-PMSZT Piezoelectric Ceramics

It is desirable for high-power piezoelectric ceramics to combine a low dielectric loss a high mechanical quality factor with a high piezoelectric constant and a high planar coupling factor. The properties of piezoelectric ceramics fluctuate with the change of temperature during the operating of the devices, sometimes, which will debase the characteristics of the devices. In addition, aging effects on the electrical properties of piezoelectric ceramics is very important in selecting optimum compositions for practical application. So it is require for high-power piezoelectric ceramics to have excellent temperature stability and time stability. From this point of view, the influences of the Zr/Ti ratio, the acceptor dopants MnO2,Ni2O3, donor dopants Nb2O5,Pr6O11, and Cr2O3 dopants on the electromechnical properties and stability of PMSZT ceramics were investigated. Moreover the mechanism of the temperature stability was discussed. The low temperature of PMSZT with NiW doping is also investigated in the paper.The phase transition of the Pba(Mn1/3Sb2/3)xZryTi1-x-yO3compositions from tetragonal phase to coexistence of tetragonal and rhombohedral phases and finally torhombohedral phase with the increasing MnSb and Zr contents. The Morphotropic phase boundary (MPB) in PMSZT system was observed near the region of x=0.05,y=0.47. When Pb contents a=1.02, the optimized properties of Pb1.02 (Mn1/3Sb2/3)0.05Zr0.47Ti0.48O3 ceramics are as follows:ε3T3 /ε0=1350, d33=320pC/N,Kp=62% , Qm=2400 , tanδ=0.0029. The changes of resonant frequency at morphotropic phase boundary for Pb1.02 (Mn1/3Sb2/3)0.05ZryTi1-x-yO3 (y=0.47) are smaller than others. From -25℃to 80℃, the average temperure coefficient of the resonant frequency(fr), electromechanical coupling factor(K31), and piezoelectric constant (d31) are 142×10-6/℃,-0.086%/℃,0.118%/℃。Results showed that the proper donor, acceptor and amphiprotic dopants optimized piezoelectric properties of the PMSZT system. Considered the effects of doping on the electromechanical properties and stability, the Mn-doping has larger effect on termperature stability than Ni-doping, Nb-doping, Pr-doping and Cr-doping of the system. From -25℃to 80℃, the average temperure coefficient of fr(72×10-6/℃), K31(-0.027%/℃), and d31 (0.100%/℃) were obtained with the composition of PMSZT+0.1wt% MnO2...