Hydrothermal synthesis and piezoelectric property of Ta-doping K0.5Na0.5NbO3 lead-free piezoelectric ceramic

Ta-doping K0.5Na0.5Nb1−xTaxO3 (x = 0.1, 0.2, 0.3, 0.4) powder was synthesized by hydrothermal approach and its ceramics were prepared after sintering and polarizing treatment in this work. The K0.5Na0.5Nb0.7Ta0.3O3 ceramics near morphotropic phase boundary (MPB), which exhibited optimum piezoelectric properties of d33 = 210 pC/N and good electromechanical coupling factors of Kp = 0.3. The domain structure has been observed from TEM images which indicates that the K0.5Na0.5Nb0.7Ta0.3O3 ceramics have good piezoelectric and ferroelectric properties for it is near the MPB.