Regulation Of Electrical Properties Of PIN-PSN-PT Ternary Ceramics

Piezoelectric materials are used in ultrasonic transducers,actuators and piezoelectric sensors because they can realize the mutual conversion between electrical and mechanical energy.Although PMN-PT has excellent piezoelectric properties(d₃₃～630 p C/N),its low Curie temperature（～150°C）limits its use in high temperature environments.Compared with PMN-PT,the Curie temperature of PIN-PT can reach 320°C,but the piezoelectric coefficient d₃₃is only 400 p C/N,the d₃₃of PSN-PT can reach 570 p C/N and the T_ccan reach 260°C.Therefore,the researchers combined PIN-PT and PSN-PT to design PIN-PSN-PT ternary ceramics.At present,the researches on the electrical properties of PIN-PSN-PT ceramics mainly focus on the components with high PSN content.Therefore,in this work,the components of PIN-PSN-PT system have been extensively explored,and the phase structure,electrical properties and temperature stability of MPB components have been studied.（1）According to the linear law of morphotopic phase boundaries,x PIN-（1-x-y）PSN-y PT ceramics were successfully prepared by solid-phase reaction method.By XRD analysis,It was found that the selected components are situated on the morphotropic phase boundary and pyrochlore phase was not found in prepared ceramics,indicated that PIN,PSN and PT can completely form a solid solution of perovskite structure.The piezoelectric constants of prepared ceramics were found to be higher than PIN-PT（400 p C/N）at 450 p C/N,and the Curie temperature was higher than 290°C.This indicated that the PIN-PSN-PT constructed by introducing PSN into PIN-PT can combine high Curie temperature and piezoelectric properties.（2）The 46.5PSN-（53.5-y）PIN-y PT（y=43,41.5,40,38.5,and 37）ceramics were prepared by solid-phase reaction method.The phase structure of PIN-PSN-PT ceramics was investigated by XRD and Raman spectroscope.And it was found with the PT content increased the phase structure of ceramics transfer to tetragonal phase.The electrical properties of the ceramics were investigated and it was found that the T_r-tdecreased with increasing PT content,while the T_cshowed a gradual increase in the opposite direction.The best overall performance of the y=41.5component ceramics,with d₃₃,k_pand T_cof 540 p C/N,0.62 and 290°C,respectively.The temperature dependence test of d₃₃and k_pshows that the residual d₃₃can still maintain 450p C/N at 210°C,and k_pcan maintain 80%of the room temperature value.It showed good temperature stability.（3）The 25.5PSN-（74.5-y）PIN-y PT（y=40.5,39.5,38.5,37.5,and 36.5）ceramics were prepared by solid-phase reaction method.The electrical properties of ceramics showed that d₃₃and k_pof ceramics increased first and then decreased,T_r-tdecreased monotonically,and T_cincreased monotonically with the increase of PT content.The composite properties of y=39.5ceramic was the best.The d₃₃,k_pand T_cof the ceramics were 535 p C/N,0.65 and 305°C,respectively.It was found that when the annealing temperature rises to 230°C,the residual d₃₃of the sample can remain at 460 p C/N,and the planar mechanical and electrical coupling coefficient k_pwas kept above 0.5,Compared with the high PSN content of the component,it can maintain the piezoelectric properties while reducing the use cost.