镧掺杂(Na_(0．5)Bi_(0．5))TiO_3压电陶瓷的结构与性能

Structure and Properties of La-Doping(Na_(0.5)Bi_(0.5))TiO_3 Piezoelectric Ceramics

采用传统陶瓷工艺制备了镧掺杂(Na_(0.5)Bi_(0.5))TiO_3无铅压电陶瓷,研究了材料的结构、介电和压电性能。发现镧掺杂有利于生成稳定的钙钛矿结构,促进了晶粒生长。镧掺杂(Na_(0.5)Bi_(0.5))TiO_3陶瓷表现出明显的弛豫特性,当镧掺杂量为5mol%时,1200℃烧结样品室温下的介电常数从630提高到855,介电损耗从5.2%减小到3.3%。适量的镧掺杂大幅降低了材料的电导率,最佳的掺杂量为1 mol%,测量温度为75℃时,该配方1200℃烧结样品的电导率σ仅为7.75148×10^(-13)S·cm^(-1),同掺杂前的9.50827×10^(-11)S·cm^(-1)前相比减小了3个数量级。

Lanthanum doping （Na0.5Bi0.5）TiO3 ceramics was prepared by conventional technique. The structure, dielectric and piezoelectric properties were studied. It is found that lanthanum doping is advantageous to form perovskite structure, and modifies grains growth. Lanthanum doping （Na0.5Bi0.5）TiO3 ceramics is still a relax ferroelectric. When the amount of lanthanum is 5mol%, sintered at 1200 ℃, the dielectric constant reaches 855, contrast to not modified （Na0.5Bi0.5）TiO3 ceramics＇ 630, while the loss tangent decreases from 5.5% to 3.3%. Lanthanum doping decreases the electrical conductivity of （Na0.5Bi0.5）TiO3 ceramics significantly. The optimum quantity is l mol%, when sintered at 1200 ℃, and measured at 75 ℃. The electrical conductivity of the samples is 7.75148×10^-13 S·cm^-1, only about 1/1000 of pure （Na0.5Bi0.5） TiO3 ceramics＇ 9.50827×10^-11 S·cm^-1.