PZN－PT－PMN电致伸缩陶瓷的介电性质

DIELECTRIC PROPERTIES OF PZH-PT-PMN-BASED ELECTROSTRICTIVE CERAMICS

对（１－ｘ－ｙ）ＰＺＮ－ｘＰＴ－ｙＰＭＮ（０＜ｘ＜０．１，０＜ｙ＜１）陶瓷的电致伸缩与介电特性进行了系统的研究。利用ＸＲＤ定性分析了在相同工艺条件下，组成及Ｋ~＋，Ｌａ^（３＋），Ｙ^（３＋），Ｗ^（６＋）等掺杂离子对微观结构、电致伸缩及介电性质的影响。分析表明：施主、受主离子掺杂对钙钛矿相的生成有不同的作用，掺杂后的材料介电常数均减小；而电致伸缩系数增大，其中适当掺Ｋ~＋和过量ＭｇＯ可使应变量得到提高；而过量ＺｎＯ使应变量减小。ＰＺＮ－ＰＴ－ＰＭＮ的应变性质和温度特性均优于ＰＺＮ，三元系的电致伸缩特性与各组成含量有关，其中铁电相含量的增大是应变量增大的原因。

The dielectric and electrostrictive properties of(1-x-y)PZN-xPT-yPMN (0<x<0.1, 0<y<1) ceramics were studied. With the help of XRD, the influences of different compositions and dopings on the microstructure and dielectric properties were analyzed. The investigated dopants are La￣(3+),Y￣(3+),K￣+ and W￣(6+). It is found that the effects of acceptor and donor doping upon the content of perovskite phase are different. The electrostrictive coefficient could be increased whereas the dielectric constant decreased with either donor or acceptor doping. Larger electrostrictive strain could be obtained by doping with K￣+ properly and excess of MgO, but excess of ZnO will decrease with the strain. It is indicated that the properties of PZN-PT-PMN ceramics are superior than PZN for thermal stability and electrostrictivity. In the ternary system,the electrostrictive properties are mainly contributed by the amount of existing ferroelectric phase.