A位非化学计量比对铌酸钾钠陶瓷极化程度的影响

研究了A位非化学计量比对铌酸钾钠陶瓷极化程度的影响。采用固相反应法制备了0.96K0.5+xNa0.5+xNbO3-0.04LiSbO3系无铅压电陶瓷,通过建立钙钛矿结构的极化模型,研究了x取不同值时,外加电场、温度对陶瓷极化及压电性能的影响。研究结果表明:A位适当过量的铌酸钾钠陶瓷极化时,对温度和电场没有强烈依赖性,可以使极化足够充分,能有效提高铌酸钾钠基陶瓷的压电性能;相反,A位不过量的铌酸钾钠陶瓷极化对温度和电场敏感,容易击穿,极化不充分,降低了铌酸钾钠基陶瓷的压电性能。

Effects of A-site Non-stoichiometry on Polarization Degree of K0.5Na0.5NbO3 Ead-free Piezoelectric Ceramics

This paper studies the effects of A-site non-stoichiometry on polarization degree of K0.5Na0.5NbO3 -AgNbO3 lead-free piezoelectric ceramics. In the research, through the preparation of Lead-free piezoelectric 0.96K0.5+xNa0.5+xNbO3-0.04LiSbO3 ceramics by solid state reaction and the building of polarization models of perovskite structure, effects of electric fields and different temperatures on the polarization and piezoelectric properties of ceramics are studied when x is at different values. Results show that the ceramics sample with the properly excessive A-site ions is not highly dependent on polarization temperature and electric field, which can realize effective polarization and improve the piezoelectric properties. On the contrary, the ceramics sample with normal A-site stoichiometry is sensitive to polarization temperature and electric field, easy to be broken down, resulting in ineffective polarization and lowered piezoelectric properties.