Orientation factor and piezoelectric property in textured (K,Na)NbO_3 system ceramics with minimal templates

摘要

To lower the sintering temperature and decrease the weight ratio of templates required for fabricating textured (K,Na)NbO3 (KNN) system ceramics, the method of preparing platelike NaNbO3 (NN) single-crystal particles for the templates was improved. The NN crystal particles synthesized by the single-step molten salt method using a mixed salt were treated by ultrasonic vibration and subsequently screened. Using these improved templates, we developed the fabrication method for the textured KNN system ceramics by which the weight ratio of the templates required for the orientation control can be reduced to 1/10 of the conventional weight ratio. The effects of decreasing the weight ratio of templates on sintering temperature, orientation factor, and piezoelectric properties were investigated. In addition, the effects of adding Bi2O3 to KNN calcined powder were also studied to suppress abnormal grain growth, which appears in the textured samples fabricated using smaller amounts of the templates. (C) 2018 The Japan Society of Applied Physics