BiFeO3掺杂0.94Bi0.5Na0.5TiO3-0.06BaTiO3压电陶瓷的相结构及电学性能

摘要

(1-x)(0.94Bi0.5Na0.5TiO3-0.06BaTiO3)-xBiFeO3 (BNBT6-xBF, 0.02≤x≤0.10, molar fraction) lead-free piezoelectric ceramics were prepared by the conventional solid-state reaction method, and the effects of BiFeO3 doping content (namely x) on the crystal structure, the dielectric, ferroelectric and electric field induced strain response properties of the ceramics were investigated.The results show that the obtained BNBT6-xBF ceramics all had a pure perovskite structure.The crystal structure of the ceramics was still near the morphotropic phase boundary with x less than 0.08 while changed to pseudo cubic structure with x equal to 0.09.The doping of BiFeO3 was favorable for the increase of ceramic dielectric constant.With the increase of BiFeO3 doping content, a phase transition from morphotropic phase to pseudocubic phase was induced in the ceramics and the ferroelectric property decreased.The electric field induced strain first increased then decreased and reached the maximum value of 0.28% with x equal to 0.09, meanwhile the normalized piezoelectric constant was 440 pm·V-1.%采用固相反应烧结工艺制备了(1-x)(0.94Bi0.5Na0.5TiO3-0.06BaTiO3)-xBiFeO3 (BNBT6-xBF,0.02≤x≤0.10,x为物质的量分数)无铅压电陶瓷,研究了BiFeO3掺杂量(即x)对陶瓷晶体结构,介电、铁电和场致应变性能的影响.结果表明:制备得到的BNBT6-xBF陶瓷均为纯钙钛矿结构;当x<0.08时,陶瓷晶体结构仍然处于准同型相界,当x=0.09时,陶瓷晶体结构开始向伪立方相转变;掺杂BiFeO3有利于提高陶瓷的介电常数;随着BiFeO3掺杂量的增加,陶瓷从铁电相向弛豫铁电相转变,铁电性能不断被削弱;陶瓷的场致应变先增大后减小,在x=0.09时达到最大,为0.28%,其等效压电常数为440 pm·V-1.