为了制备高性能无铅压电陶瓷,采用固相合成法和水热法合成了(K_xNa_1-x)NbO₃ (KNN)无铅压电陶瓷粉体。利用压制成型法在不同压力下成型,对不同粉体的烧结性能进行了对比,研究了粘结剂(PVA)添加量和陶瓷密度之间的关系,测量了用不同电压极化后陶瓷的压电特性,以及介电常数与温度之间的关系。结果表明:与固相合成法相比,水热合成的粉体有更好的烧结性,添加K会降低陶瓷的烧结性,陶瓷的密度对烧结温度非常敏感。1050 ℃保温2 h得到的K_0.5Na_0.5NbO₃陶瓷具有较高的压电常数d33 (90 pC/N),该陶瓷的居里温度为410 ℃。

To fabricate high-performance lead-free piezoelectric ceramics, both the solid-state reaction method and the hydrothermal method were used to synthesize the (K_xNa_1-x)NbO₃ (KNN) lead-free ceramic powders in this work. The ceramic powders were shaped using press forming method at different pressures and the sintering properties of ceramics fabricated from different powders were investigated. Then,the relationship between the account of PVA and the density of ceramics was discussed. The piezoelectric constants of the KNN ceramics polarized at the different voltages, and the dielectric constants against temperatures were also measured. The results show that the powder prepared by hydrothermal method has better sinterability compared to that prepared by solid-state reaction method. Moreover,the addition of K content lowers the sinterability of ceramics. The density of ceramics is very sensitive to the sintering temperature. The K_0.5Na_0.5NbO₃ ceramics fabricated at 1050 ℃ for 2 h has higher d₃₃ (90 pC/N), and its Curie temperature is 410 ℃.