The Effect Of Ionic Doping On Microstructure And Piezoelectric Properties Of BCZT Based Lead-Free Ceramics

Lead-based piezoceramics are extensively used in war industry and daily life such as actuator,motor and transducer due to the conversion of electric energy and mechanical properties.But the Lead is toxic and harmful to human beings and environment,the scientists and researchers are contributed to explore free-lead piezoelectric materials substitution Lead-based piezoceramics.In the work,the author used ionic doping and sintering modified method to systematically study the effect of evolution of microstructure and electric properties on BCZT-based lead-free piezoceramics.Research results as follows:1.Having researched the effect of Sm₂O₃ doping on piezoelectric properties,microstructure,ferroelectric and dielectric properties of?1-x?Ba_0.85Ca_0.15Zr_0.08Ti_0.92-xSm free-lead piezoceramics.The grain size decreased gradually when the Sm³⁺is doped.Meanwhile,piezoelectric coefficient decreased gradually.The pure Ba_0.85Ca_0.15Zr_0.08Ti_0.92.92 ceramics is of prior piezoelectric constant(d₃₃³20 pC/N),and the hysteresis loops become narrow gradually.The dielectric constant drop gradually.2.Having studied the effect of GeO₂ doping on electrical properties of the?1-x?Ba_0.85Ca_0.15Zr_0.08Ti_0.92—xGe?x=0,0.03,0.06,0.09,0.12,0.15 wt.%?free-lead piezoceramic.When the dopant is 0.03 wt.%,piezoelectric properties is optimal(d₃₃³48 pC/N),and the remanent polarization and coercive field are P_r³.39C/cm²and E_c⁰.47 kV/mm,respectively.The ceramic is hardly nonporous and the grain size is optimal at x=0.03 wt.%.3.Having studied the effect of Ta₂O₅ doping on electric properties of?1-x?BCZT-xTa₂O₅+0.6 wt.%Li₂CO₃?x=0.02,0.04,0.06,0.08 wt.%?free-lead ceramics.The enhanced piezoelectric properties and Curie temperature are obtained by doping Ta⁺⁵and Li⁺¹.The piezoelectric constant is³46 pC/N at x=0.04 wt.%,and the T_c and permittivity are equal to 129?and 13693 at x=0.02 wt.%,respectively.4.Having researched the effect of microwave sintering on piezoelectric properties and microstructure of the?1-x?BCZT-xTa₂O₅+0.6 wt.%Li₂CO₃ free-lead piezoceramic.The sintering temperature and soaking time of ceramics are 1300?in the microwave oven,and the electric properties are optimal in the coexistence of rhombohedral phase and tetragonal phase(d₃₃³45 pC/N)at x=0.04 wt.%.On the contrary,the electric properties of ceramics are inferior in the sintering furnace as the same conditions(d₃₃²01 pC/N).