Research On Fabrication And Properties Of PMN-PZT Based Ceramics And MFC Piezoelectric Actuators

In this work,ternary system piezoelectric ceramics of x Pb(Mg_1/3Nb_2/3)O₃-?1-x?Pb(Zr_0.45Ti_0.55)O₃?PMN-PZT?and modified PMN-PZT ceramics of 0.3Pb(Mg_1/3Nb_2/3)O₃-0.7Pb(Zr_0.45Ti_0.55)O₃+x wt% Fe₂O₃ were synthesized by conventional solid-state method.The influences of the PMN and Fe₂O₃ content respectively on the phase structure,micromorphology and electrical properties of the ceramics were investigated in order to determine the most appropriate composition of the piezoelectric cereamics with two systems.Then on this basis,0.3Pb(Mg_1/3Nb_2/3)O₃-0.7Pb(Zr_0.45Ti_0.55)O₃+0.6 wt% Fe₂O₃ piezoelectric ceramics which have the best comprehensive properties were used to fabricate Macro Fiber Composite actuators by means of cutting and filling process.The properties of the actuators influenced by the epoxy resin coating process and the width of piezoelectric ceramic fibers were investigated at last.Firstly,after analyzing the properties of ternary system piezoelectric ceramics of x Pb(Mg_1/3Nb_2/3)O₃-?1-x?Pb(Zr_0.45Ti_0.55)O₃?x=0.22,0.26,0.30,0.34?,the results show that the ceramics of 0.3Pb(Mg_1/3Nb_2/3)O₃-0.7Pb(Zr_0.45Ti_0.55)O₃ locate near the morphotropic phase boundary and have the best comprehensive properties.The performance parameters are:?_r=1861,tan?=0.021,T_m=259 ?,d₃₃=518 pC/N,k_p=0.59,Q_m=77,E_c=10.41 k V/cm,P_r=43.48 ?C/cm².Secondly,added x wt% Fe₂O₃?x=0.2,0.4,0.6,0.8,1.0?into ternary system piezoelectric ceramics of 0.3Pb(Mg_1/3Nb_2/3)O₃-0.7Pb(Zr_0.45Ti_0.55)O₃ with the best properties.The ceramics of 0.6 wt% Fe₂O₃ locate near the morphotropic phase boundary by investigating microstructure and electrical properties,and have the best comprehensive performance.The performance parameters are: ?_r=2874,tan?=0.015,T_m=263 ?,d₃₃=728 p C/N,k_p=0.69,Q_m=57,E_c=9.64 k V/cm,P_r=53.71 ?C/cm².Finally,0.3Pb(Mg_1/3Nb_2/3)O₃-0.7Pb(Zr_0.45Ti_0.55)O₃+0.6 wt% Fe₂O₃ piezoelectric ceramics were used to fabricate Macro Fiber Composite actuators by means of cutting and filling process.The results show that the layer of epoxy resin is thinner and more uniform by spin-coating process and the maximum thickness is 15 ?m,promoting the electrical properties of the actuators.MFC actuators with piezoelectric ceramic fibers whose width are 0.5 mm have the best piezoelectric properties and the performance parameters are: ?_r=1007,tan?=0.061,d₃₃=422 p C/N,k₃₃=0.41,E_c=4.59 k V/cm,P_r=26.10 ?C/cm².