以分析纯NaOH,KOH,Li2CO3,Nb2O5,Sb2O3等为原料,采用微波水热法合成(1-x)K0.55Na0.45NbO3-xLiSbO3(KNNLS,X=0.03-0.07m01)粉体,分析了粉体的晶体结构与形貌。以该粉体制备压电陶瓷,系统研究了LiSbO。含量对压电陶瓷结构与性能的影响。研究结果表明:微波水热法在220℃下保温30min可以合成具有纯正交钙钛矿结构的KNNLS(x=0.03~0.07)粉体,粉体呈立方状,尺寸约0.5~1μm。利用该粉体制备的压电陶瓷结构致密,晶粒大小分布均匀。当x-0.05时,该组成陶瓷具有最佳的综合压电性能:压电常数d33=110pC/N,平面机电耦合系数kp=0.29,介电常数ε^T33/ε0=466,介质损耗tanδ=1.4%以及机械品质因素Qm107。关键词微波水热法;铌酸钾钠;LiSbO3;无铅压电陶瓷;钙钛矿
Using NaOH, KOH, Li2CO3, Nb205 and Sb2O3 as raw materials, (1-x)K0.56Na0.45NbO3-xLiSbOa (KNNLS, x = 0.03 - 0.07 mol)powders were synthesized by microwave hydrothermal method. The crystal structure and micro morphology were detected. The effect of the LiSbO3 content on the microstructure and properties of KNNLS piezoceramics prepared from the powders was investigated. Results indicated that KNNLS(x = 0.03 -0.07)powders in pure orthorhombic perovskite structure can be synthesized at 200℃ for 30 min by microwave hydrothermal method, and the particle exhibits a regular cubic shape with the size of 0.5μm. The piezoceramic prepared from the powders has dense microstructure with grain distribution uniformity. When x = 0.05mol, the ceramic exhibits the best piezoelectric performance: piezoclectric constant d~=110 pC/N, planar electromechanical coupling factor kp=0.29, dielectric constant ε^T33/ε0 =466, dielectric loss tanδ=1.4% and mechanical quality factor Q,,=107.