Li Yueming, Su Linlin, Wang Zhumei, Hong Yan, Shen Zongyang, WuYing

（Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen, Jiangxi 333403, China）

Abstract:Using NaOH, KOH, Li₂CO₃, Nb₂O₅ and Sb₂O₃ as raw materials, (1-x)K_0.55Na_0.45NbO_3-xLiSbO₃（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 shapewith the size of 0.5 ~1μm. 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 d₃₃=110 pC/N, planar electromechanical coupling factor k_p=0.29, dielectric constant ε^T ₃₃/ε₀ =466，dielectric loss tanδ =1.4% and mechanical quality factor Qm=107.

Key words： microwave hydrothermal method; potassium sodium niobate; LiSbO₃; lead-free piezoceramic; perovskite