Effect Of Zinc Oxide On Microstructure And Electrical Properties Of BCZT-based Lead-free Piezoelectric Ceramics

PZT-based piezoelectric ceramic materials are widely used in daily production and military industry because of their excellent piezoelectric properties,such as transducers,brakes,motors,etc.But PZT-based piezoelectric ceramic lead volatile in sintering process will pollute the environment and damage to human health.In order to develop environmentally friendly piezoelectric ceramic materials,researchers are working to develop lead-free piezoelectric ceramic materials to replace PZT-based piezoelectric materials.BCZT piezoelectric ceramics?BCZT?is a new type of binary ceramics,which has high piezoelectric properties near its quasi-homogeneous phase boundary?MPB?.However,BCZT piezoelectric ceramics still have many disadvantages?such as low Curie temperature and high sintering temperature?,which limit its application.Studies have shown that doping zinc oxide in PZT,BNT and KNN based piezoelectric ceramics can effectively promote grain growth and improve the electrical properties of ceramics.In this paper,BCZT piezoelectric ceramics with excellent properties were prepared by traditional solid-phase sintering method,and the influence of zinc oxide introduction on the structure and electrical properties of BCZT lead-free piezoelectric ceramics was systematically studied.The research results are as follows:The effects of ZnO content on the phase composition,microstructure,piezoelectric properties and ferroelectric property of the(Ba_0.85Ca_0.15)(Ti_0.9Zr_0.1)O₃-xwt.%ZnO?x=0,0.025,0.05,0.075,0.1?ceramics were studied.The results show that when the doping amount of zinc oxide is 0.05,the piezoelectric ceramic sample has the best comprehensive performance:d₃₃=341p C/N,k_p=0.41,?_r=4381,tan?=1.38%,P_r=7.31?C/cm²,E_c=2.53k V/cm.The effects of ZnO particle size on phase composition,microstructure,piezoelectric properties,dielectric relaxation behavior and ferroelectric properties of(Ba_0.85Ca_0.15)(Ti_0.9Zr_0.1)O₃-0.05wt.%ZnO piezoelectric ceramics were studied.Through comprehensive analysis,it can be concluded that when the particle size of doped zinc oxide is 5?m,the piezoelectric ceramic sample has the best comprehensive performance:d₃₃=337p C/N,k_p=35.8%,?_r=4399,tan?=2.25%,P_r=8.28?C/cm²,E_c=2.57k V/cm.The effects of Bi Al O₃ content on the phase structure,microstructure,piezoelectric and ferroelectric properties of(Ba_0.85Ca_0.15)(Ti_0.9Zr_0.1)O₃ ceramics were studied.Through comprehensive analysis,it can be concluded that the piezoelectric ceramic sample has the best comprehensive performance when the Bi Al O₃ doping amount x=0.02:d₃₃=332p C/N,k_p=39.9%,?_r=3320,tan?=1.56%,P_r=8.35?C/cm²,E_c=2.3k V/cm.BCZT-BAO+xwt.%ZnO piezoelectric ceramics were successfully prepared by solid phase sintering method using 0.98(Ba_0.85Ca_0.15)(Ti_0.9Zr_0.1)O₃-0.02Bi Al O₃+xwt.%ZnO ceramic formula.The effects of ZnO content on the phase structure,microstructure and piezoelectric properties of ceramics were studied.The results show that when the doping amount of ZnO is 0.025,the piezo-ceramic sample has the best comprehensive performance:d₃₃=343p/CN,k_p=41%,?_r=4387,tan?=2.27%.The polyphase composite functional ceramics of lead-free piezoelectric ceramics BCZT-BAO and ZnO-Pr₆O₁₁ were studied.The samples were studied from the aspects of sintered phase,microstructure and electrical properties.The results show that when the molar ratio is 1.2:1 and 1:1.2,the sample has both piezoelectric and pressure-sensitive properties.When the ratio is 1:1,the sample has no piezoelectric property.When the molar ratio is 1.4:1,the sample has no pressure-sensitive performance.