Microstructures and electrical properties of KNbO_3 doped (Li,Ta,Sb) modified (K,Na)NbO_3 lead-free ceramics by two-step sintering

摘要

In this study, 0.95(Na_(0.52)K_(0.44)Li_(0.04))(Nb_(0.88)Sb_(0.08)Ta_(0.04))O_3-0.05KNbO_3 (NKLNST-0.05KN) ceramics were prepared by two-step sintering method. The effects of KN and sintering temperature on the microstructures and piezoelectric properties of NKLNST-0.05KN were discussed. The addition of KN aids plays an important role in grain growth behavior and allows lower first-step sintering temperature. And with the extension of the second-step sintering time, the liquid phase with low Na content forms solid solution with the NKLNST ceramics and the nano-sized white spots with high Na content crystallize on the surface of grains. The P-E hysteresis loops of the ceramics are well-saturated, and NKLNST-0.05KN ceramics demonstrate good piezoelectric property d_(33) = 328 pC/N under 1130/ 950 ℃ sintered by two-step sintering.