Study On Preparation And Doping Modification Of Barium Calcium Zirconate Titanate Lead-Free Piezoelectric Ceramics

Because of piezoelectric effect, piezoelectric ceramics have a very important role in the production and life of human beings. BCZT lead-free piezoelectric ceramics have been paid more and more attention because of their excellent piezoelectric properties and the characteristic of the human environment. But the sintering temperature of BCZT lead-free piezoelectric ceramics is too high, and the Curie temperature is too low to get a great improvement. In this paper, BCZT lead-free piezoelectric ceramics were prepared by conventional solid state method, and the effects of Nd2O3, Co2O3, Bi2O3, Bi Fe O3 and Li2CO3 on the phase structure,microstructure, electrical properties and Curie temperature of BCZT lead-free piezoelectric ceramics were investigated, some main conclusions are follow:(1) Nd2O3 doping did not change the perovskite structure of(Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 ceramics, the grain size of the lead-free piezoelectric ceramic increased first and then decreased. With the increase of Nd2O3, the piezoelectric constant, the planar eletromechanical coupling coefficient, the dielectric loss and Curie temperature of BCZT ceramics firstly increased and then decreased,and the density and the dielectric constant firstly decreased and then increased. When Nd2O3 doping amount was 0.2 wt.%,(Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 piezoelectric ceramics materials sintered at 1420? possessed the best comprehensive performance: d33=228p C/N,KP=38.9%,?r=2846, tan ?=0.018,Tc= 101?,?=4.805 g/cm3.(2) Co2O3 doping did not change the perovskite structure of(Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 ceramics, the grain size of the lead-free piezoelectric ceramic had a decreasing trend. With the increase of Co2O3, the piezoelectric constant,the planar eletromechanical coupling coefficient, the dielectric constant and the density of BCZT ceramics firstly increased and then decreased, and the dielectric loss and Curie temperature decreased. When Co2O3 doping amount was 0.4 wt.%,(Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 piezoelectric ceramics materials sintered at 1360 ?possessed the best comprehensive performance: d33=334 p C/N,KP=40.8%,?r=3593,tan ?=0.021,Tc=66?,?=5.540 g/cm3.(3) Bi2O3 doping did not change the perovskite structure of(Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 ceramics, the grain size of the lead-free piezoelectricceramic had a decreasing trend. With the increase of Bi2O3, the piezoelectric constant,the planar eletromechanical coupling coefficient, the dielectric constant and the density of BCZT ceramics firstly increased and then decreased, and the dielectric loss increased, Curie temperature decreased. When Bi2O3 doping amount was x=0.002,(Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 piezoelectric ceramics materials sintered at 1450 ?possessed the best comprehensive performance: d33=266 p C/N,KP=38.4%,?r=3096,tan ?=0.018,Tc= 100?,?=5.028 g/cm3?(4) Bi Fe O3 doping did not change the perovskite structure of(Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 ceramics, the grain size of the lead-free piezoelectric ceramic had a decreasing trend. With the increase of Bi Fe O3, the density and the dielectric constant of BCZT ceramics firstly increased and then decreased, and the piezoelectric constant, the planar eletromechanical coupling coefficient and Curie temperature decreased, the dielectric loss firstly decreased and then increased. When Bi Fe O3 doping amount was 0.3 mol%,(Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 piezoelectric ceramics materials sintered at 1450? possessed the best comprehensive performance:d33=307 p C/N,KP=30.8%,?r=2240, tan ?=0.029,Tc= 100?,?=4.892 g/cm3.(5) Li2CO3 doping did not change the perovskite structure of(Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 ceramics, the grain size of the lead-free piezoelectric ceramic had a increasing trend. With the increase of Li2CO3, the piezoelectric constant, the planar eletromechanical coupling coefficient, the dielectric constant and the density of BCZT ceramics firstly increased and then decreased, and the dielectric loss firstly decreased and then increased, Curie temperature decreased. When Li2CO3 doping amount was 0.3 wt.%,(Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 piezoelectric ceramics materials sintered at 1100? possessed the best comprehensive performance: d33=134p C/N,KP=35.1%,?r=1734, tan ?=0.028,Tc= 87.4?,?=5.480 g/cm3.