中文摘要：

采用传统固相法制备了（Ko．49Nao．51）1-xLix（Nb0.77Ta0．18Sb0．05）Q--0．005BaZr03（x=0．02～0．06，KNNLTSBZx）无铅压电陶瓷。用x射线衍射、扫描电子显微镜及精密阻抗分析仪分析了Li含量（x）对样品的晶相组成、显微结构、压电及介电性能的影响。发现：所研究的组成范围内，陶瓷样品均具有纯的钙钛矿晶体结构；随着Li含量（x）的增加，室温样品的晶体结构由正交相逐渐向四方相转变，Curie温度（Tc）向高温方向移动，而正交一四方相变温度（To-t）则向低温方向变化，且当x≥0．04时，B。已经移到室温以下，0．04≤x≤0．06范围为陶瓷的正交一四方共存的多型相转变组成，当x=0．04时，陶瓷具有最佳的压电、介电性能：压电常数d33=240pC／N，平面机电耦合系数k，=44．7％，相对介电常数ε33^t/ε0=2090，介电损耗tanδ=2．7％。

英文摘要：

（K0.49 Na0.51 ） 1-x Lix （Nb0.77 Ta0.18 Sb0. 05 ） 03 -- 0. 005BaZrO3 （x = 0. 02-- 0. 06, abbreviated KNNLTSBZx） lead-free pie- zoelectric ceramics were prepared by a conventional solid state reaction method. The effect of Li amount on the phase, micro- structure, piezoelectric properties and dielectric properties of samples was analyzed by X-ray diffraction, scanning electron mi- croscopy and precision impedance analysis, respectively. The results show that all the samples possess a pure perovskite struc- ture. When the amount of Li increases, the phase structure of the samples at room temperature changes from orthorhombic to tetragonal symmetry, the Curie temperature Tc moves to a higher temperature, but orthorhombic-tetragonal phase transition temperature T~.t moves to a lower temperature, even moves to the temperature below room temperature as x≥0.04. In addi- tion, a polymorphic phase transition from orthorhombic to tetragonal symmetry occurs in the composition range of 0. 04≤x≤ 0.06. The ceramic samples in the composition when x： 0. 04 have optimal electrical properties, i. e. , piezoelectric constant （dss） of 240 pC/N, planar electromechanical coefficient （kp） Of 44. 7%, relative dielectric constant （ε33^t/ε0） of 2 090, and die- lectric loss （tanδ） of 2. 7%.