中文摘要：

用常规氧化物固溶法制备了 （Na0.520＋xK0.480）0.915Li0.085NbO3 （x=0—0．025）无铅压电陶瓷，研究了过量Na的掺杂量对其烧结温度、微观结构及压电性能的影响。结果表明，过量Na掺杂在烧结过程中促进液相的产生，导致样品烧结温度显著降低。室温下样品均为四方结构。随X的增加，样品的斜方一四方相变温度to-T趋向低温。当X从0．010增大到0．025时，Qm从131提高到238，tanδ和d33分别从0．034和125pC／N下降至0．012和105pcm，表明过量Na实际上起到了‘便性掺杂”的作用。

英文摘要：

（Na0.520＋xK0.480）0.915Li0.085NbO3 （x = 0 - 0.025） lead-free piezoceramics were prepared using conventional oxide solid-solution technique, and the effects of excess Na doping amounts on the sintering temperatures, microstructures and piezoelectric properties of samples were investigated. The results indicate that excess Na doping facilitate the production of liquid phase during sintering and result in obvious decrease of sintering temperature of samples. All of the samples exhibit tetragonal structures at room temperature and a downward trend of orthorhombic-tetragonal phase transition temperature （to-r） with the increase of x. The increase of mechanical quality factor （Qm） from 131 to 238, the decrease of dielectric loss （tanδ） from 0.034 to 0.012 and the decrease of piezoelectric coefficient （d33） from 125 pC/N to 105 pC/N when x increases from 0.010 to 0.025, demonstrate that excess Na doping can lead to an effect of ＂hardness doping＂ on samples.