In this paper, the 0.95(Na_0.5K_0.5)_0.04[(Nb_0.8Ta_0,20)_0.994Co_0.015]O_3(abbreviated as NKNT) + 0.05KNbO_3 lead-free piezoelectric ceramics were synthesized by the conventional mixed oxide method route with normal sintering. And also, the effects of calcination temperature on the microstructure, dielectric properties, and piezoelectric properties were investigated. A polymorphic phase transition(PPT) between orthorhombic and tetragonal phases was observed in specimens calcined at 810℃∼850℃. The ceramics calcined at 830℃ showed excellent piezoelectric properties: d_33= 179 pC/N, k_p= 0.384, Q_m= 79.73). These results indicate that the ceramic is a promising candidate material for lead-free piezoelectric ceramics.
