Study Of Low-loss PMS-PZT Piezoelectric Ceramics

Recently, research works on high-power piezoelectric ceramics become aninteresting and popular topic due to their increasing application in piezoelectricmotors, transformers, piezoelectric transducers and other fields. Consequently, it isdesirable for high-power piezoelectric ceramics to be possessed with excellentcomprehensive performances, specifically, a low dielectric loss, a high mechanicalquality factor, a high piezoelectric constant and a high planar coupling factor. In orderto achieve that goal, a kind of PMS-PZT ternary system piezoelectric ceramic withgood properties was selected. The doping effect and preparation technology were alsostudied in the paper.Pb1.02(Mn1/3Sb2/3)x(Zr0.47Ti0.48)(1-x)/0.95O3(with composition x=0.01,0.03,0.05,0.07)ceramics were fabricated through a conventional solid-state reaction method. Then,the effect of MnSb content to the performance was studied. Besides, in considerationof the sample phase measured by X-ray diffraction (XRD), and the surfacemicrostructure by scanning electron microscope (SEM), we can deduced that TheMorphotropic Phase Boundary (MPB) in PMS-PZT system was observed near theregion of x=0.05. The optimum comprehensive properties turned out to be:piezoelectric coefficient d33=340pC/N, mechanical quality factor Kp=0.585, dielectricloss tanδ=0.31%, relative dielectric constant εT33/ε0=1369, and Curie temperatureTc=320℃.The effect of poling technique, two kind of pressing methods and differentsynthesized methods were researched about the material with the best formula. Theoptimized dc electric field was3kv/mm and best polarization temperature were140℃.After poling in that condition for20minutes, lower the temperature to120℃andremove the polarization electric field in the end. The study of poling technique showthat increasing poling temperature is an effective method to improve polarization.Experiments results showed that the traditional oxide method was beneficial forexcellent properties. Compared with dry pressed ceramics, the ceramics through coldisostatic compaction have smaller crystal grain and higher density, and thus optimizedielectric properties and piezoelectric properties. Cold isostatic compaction wasconcluded as the appropriate molding method in our experiment, and the best moldingpressure was360MPa. The property parameters are listed as follows: d33=353pC/N,εT33/ε0=1659, tanδ=0.20%. In the end, the doping modification of cerium oxide (CeO2) and2CaO-Fe2O3onPb1.02(Mn1/3Sb2/3)0.05Zr0.47Ti0.48O3piezoelectric ceramics were also carried outrespectively. Specifically, the influence of CeO2content was studied, and theexperiment showed that CeO2served as the hard dopant in this system. In addition,the influence of sintering methods on properties were also studied aboutPb1.02(Mn1/3Sb2/3)0.05Zr0.47Ti0.48O3ceramics doped with CeO2. Specimens sintered in anerected crucible turned out to have better comprehensive performance than those in anupturned crucible. The research of PMS-PZT doped with different content of2CaO-Fe2O3can be concluded that the moderate content of2CaO-Fe2O3couldimprove Tc of PMS-PZT.