Study On Microstructure And Electrical Properties Of BZT-BCT Piezoelectric Ceramics

In this paper,0.5[BaTi0.8Zr0.2O3]-0.5[Ba0.7Ca0.3TiO3](BZT-BCT) Gel have beensuccessfully synthesized by the method of Sol-gel, and then the ceramic powers havebeen successfully prepared by the Self propagating method. At last, the ceramicsamples have been prepared by the high temperature annealing. On the basis ofexperiment, the effect of binder PVA and the annealing temperature have beendemonstrated in the crystallization process of the ceramics; and then the effect ofbinder PVA(polyvinyl alcohol)have been studied for ferroelectric properties of theceramics, on the basis of the research, the piezoelectric properties of the ceramicshave been analyzed; the influence of annealing temperature have been systematicallystudied for the dielectric properties of the mixed of PVA of ceramics.The analysis of the ceramics structure of high resolution XRD revealed that: theeffects of binder PVA on crystallization behavior have been discussed by twoexperiments of annealing temperature at1200℃and1350℃, the degree ofcrystallization of the mixed of PVA of ceramics are much better, and according to thecharacteristic peaks of (110), from the change trend of the half peak widths, it can befound that the grains size also show the trend of increase; Through the analysis of thedifferent annealing temperature of ceramic samples, in the XRD diagram, the resultsexhibit that the diffraction peak intensity of X-ray show the trend of increasing alongwith the increasing of temperature the ceramics, and the degree of crystallization ofceramics are much perfect. The half peak widths of characteristic peaks of (110)show a trend of decreasing, and the grains size show a trend of increasing.For the electrical property of the ceramics, the ferroelectric properties ofceramics have been studied，the results show that the ferroelectric properties ofceramics are much better than the without PVA of ceramics, and with the increasingof the electric field, the hysteresis loops are much obvious, because the electric field is too small to reflect a little characteristics of ferroelectric, so the residualpolarization intensity, the coercive field and saturated polarization are so small, butits still show the trend of increase; additionally, the piezoelectric performances ofceramics have been analyzed, the results show that the equivalent piezoelectriccoefficient increase along with the rising of the test voltage; the dielectric propertiesof the ceramics have been systematically studied, it has been found that the dielectricloss of ceramics decrease gradually along with the increasing of test frequency, itsexhibit excellent high frequency characteristics. And with the rising of annealingtemperature, the dielectric loss of ceramics decrease gradually, the dielectricconstants of the ceramics show a trend of increasing, the insulating ability ofceramics slightly decrease, the conductivity has risen by an order of magnitude.