中文摘要：

采用传统固相烧结法制备0．92（Na0.51K0.49-xLix）NbO3-0．02K0．5Bi0．5TiO3-0．06BaZrO3（简写为NKLNx—KBT—BZ，x=0．00～0．05）系无铅压电陶瓷。用x射线衍射仪、扫描电子显微镜、精密阻抗分析仪及铁电性能测试仪等研究了Li＋含量对该体系陶瓷的晶相、显微结构和电性能的影响。结果表明：在研究组成范围内，陶瓷均具有单一的钙钛矿结构，随着Li＋含量的增加，晶体结构从菱方转变为四方结构，并且经过菱方·四方两相共存的准同型相界（MPB）组成区域0．01〈x〈0．03。在MPB区域的四方相边界x=0．03处获得优异的电性能：d33=227pC／N，kp=39．3％，Qm=69，ε^T 33／ε0=1642，tanδ=2％，Pr=13．3μC／cm^2，Ec=1．64kV／mm。

英文摘要：

0.92（Na0.51K0.49-xLix）NbO3-0.02K0.5Bi0.5TiO3-0.06BaZrO3 （ NKLNx-KBT-BZ, x = 0 - 0.05 ） lead-free piezoelectric ceramics were prepared by traditional solid state reaction sintering method. The effect of Li ＋ contents on the crystal structure, microstrueture and electrical properties of the NKLNx- KBT-BZ ceramics was investigated by X-ray diffractometer, scanning electronic microscopy, precision impedance analysis and ferroeleetrie tester. The results indicated that all ceramic samples have a pure perovskite structure. As the Li ＋ contents increasing, the crystal structure transforms from rhombohedral to tetragonal symmetry across a morphtropic phase boundary（MPB） with the composition range of 0.01 〈 x 〈 0.03. The tetragonal side of the MPB at x = 0.03 exhibits optimal electrical properties ： piezoelectric constant d33 = 227 pC/N, planar electromechanical coupling factor kp = 39.3%, mechanical quality T factor Qm = 69, dielectric constant s33/80 = 1642, dielectric loss tarδ = 2%, remanent polarization Pr = 13. 3 μC/cm2, and the coercive field Ec = 1.64 kV/mm.