摘要
研究了三方、四方共存[即准同型相界(morphotropic phase boundary,MPB)]附近(0.99–x)Bi0.5Na0.5TiO3–xBi0.5K0.5TiO3–0.01K0.5Na0.5NbO3[(0.99–x)BNT–xBKT–0.01KNN,x=0.16～0.23]无铅压电陶瓷的电学性能与其结构之间的变化关系。X射线衍射分析表明,随着x的增大,陶瓷材料相结构由三方相转变为四方相。当x=0.20时,(111)和(200)面衍射峰均形成劈裂峰,标志着该组分的相结构由三方–四方相共同组成,形成MPB区。样品的介电温谱表明,铁电–反铁电转变温度(Td)随着x的增大而减小,但Curie点(TC)并未明显变化。电致应变(S)随着x的增大,呈现先增加后减小的趋势,并在x=0.20时得最大值0.46%,此时动态压电系数约为575 pm/V。电滞回线显示,陶瓷样品的剩余极化强度Pr和矫顽场Ec都随着x的增大而减小,分别由41.5μC/cm2降为15.2μC/cm2和由46.5kV/cm降为15.0kV/cm,并伴随着电滞回线由扁平到束腰的形状变化,呈现从铁电相特性到反铁电相特性的转变过程。
A relationship between the electric properties and the structure of lead-free ceramics（0.99–x）Bi0.5Na0.5TiO3–xBi0.5K0.5TiO3– 0.01K0.5Na0.5NbO3 [（0.99–x）BNT–xBKT–0.01KNN,x = 0.16–0.23] near the region where tetragonal and rhombohedral phase co-existed（morphotropic phase boundary,MPB） was investigated.The analysis by X-ray diffraction indicated the transition from rhombohedral to tetragonal phase as the BKT content x increased.The peak splits of（111） and（200） occurred simultaneously at x = 0.20,indicating the ceramic had a structure of coexistence of rhombohedral and tetragonal phases（viz.formed MPB）.The results of dielectric temperature spectra showed that the ferroelectric to anti-ferroelectric transition temperature Td decreased with increasing x,while the Curie point（TC） showed slight changes.The electrostrictive strain（S） firstly increased and then decreased,giving a maxi-mum value of 0.46% at x = 0.20,which equaled to the dynamic piezoelectric coefficients of 575 pm/V.The electric hysteresis loop test exhibited that the remanent polarization Pr and coercive field Ec decreased from 41.5 μC/cm2 to 15.2 μC/cm2 and from 46.5 kV/cm to 15.0 kV/cm,respectively,with increasing x,and the loops showed a transition from ferroelectric properties to anti-ferroelectric properties.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2012年第3期385-390,共6页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金重点项目(50932007)资助
关键词
无铅压电陶瓷
准同型相界
电致应变
压电–铁电性能
lead-free piezoelectric ceramics
morphotropic phase boundary
electrostrictive strain
piezoelectric–ferroelectric property
