Sintering Characteristic and Piezoelectric Properties of Lead-free (K0.5 Na0.5)NbO3-LiNbO3 Ceramics

Lead-free (1-x)(1-x)(K0.5Na0.5)NbO3- xLiNbO3 piezoelectric ceramics were prepared by a traditional ceramic processing. The sintering characteristic, the microstructure and electrical properties of (1-x)(K0.5Na0.5)NbO3- LiNbO3 ceramics were investigated. Results show that all specimens exhibit a pure perovskite structure and the phase structure at room temperature transforms from orthorhombic to tetragonal with the increase of LiNbO3.The microstructure of (1-x)(K0.5Na0.5)NbO3- LiNbO3 ceramics exhibits apparent difference due to different amounts of LiNbO3. The sinterability of (1-x)(K0.5Na0.5)NbO3- LiNbO3 is improved and the sintering temperature is lower than that of pure KNN ceramics. The (1-x)(K0.5Na0.5)NbO3- xLiNbO3(x=0.06) ceramics exhibits an excellent piezoelectric properties with the piezoelectric constant d33, the electromechanical coupling coefficients kp and kt of 205pC/N, 40.3% and 49.8%, respectively.