中文摘要：

采用传统陶瓷工艺制备了（K0.5NaO.5）1-xLixNb1-ySbyO3（KNLNSx-y,x=0～10％（摩尔分数），y=2％～8%（摩尔分数））系无铅压电陶瓷，研究了Li＋和Sb^5＋的取代对KNLNSx-y系材料的相变弥散性的影响。结果表明，在所研究的组成范围内，KNLN-Sx-y陶瓷都形成了单一的钙钛矿结构，Li^＋和Sb^5＋进入了KNN晶格形成固溶体；随着Li含量的增加，KNLNSx-5陶瓷四方-立方相变的弥散性有所减弱；随着Sb含量的增加，KNLNS2-y陶瓷四方-立方相变的弥散性有所增强。采用修正的居里一外斯定律能够较好的描述KNLNSx-y陶瓷在高于居里温度情况下的介电常数与温度的关系；利用有序-无序理论对该介电弥散现象进行了解释。

英文摘要：

（K0.5NaO.5）1-xLixNb1-ySbyO3（ KNLNSx-y, x = 0-10mol%, y = 2mol%-8mol%） lead-free piezoelectric ceramics have been synthesized by conventional mixed oxide method. The effects of Li and Sb substitutions on the characteristic of the diffuse phase transition of the ceramics were investigated. The results indicate that during the sintering Li＋ and Sb5＋ diffuse into the K0.5 Na0.5 NbO3 lattices forming a solid solution with perovskite structure; with the increasing amount of Li, the characteristic of the diffuse phase transition of the KNLNSx-5 ceramics decreases; and with the increasing amount of Sb the characteristic of the diffuse phase transition of the KNLNSx-y ceramics increases. At the temperature higher than the Curie temperature of the ceramics, the thermal variation of the dielectric constant of the KNLNSx-y ceramics is well described by the modified Curie-Weiss law and the related mechanisms for the diffuse phase transition of the ceramics were also discussed.