Effect of Li_2O Addition on Piezoelectric Properties of NKN-5LT Ceramics

摘要

Recently alkali oxide materials, such as sodium - potassium niobate have drawn much attention due to their ultrasonic applicability and are also considered as promising candidates for a piezoelectric lead-free system. However, it is difficult to sinter such NKN-based materials via conventional sintering process. Therefore, in this study, dense 0.95(Na_(0.5)K_(0.5))NbO_3-0.05LiTaO_3 (NKN-5LT) ceramics were developed by conventional sintering process. Sintering temperature was lowered by adding Li_2O as a sintering aid. The electrical properties of NKN-5LT ceramics were investigated as a function of Li_2O concentration. At the addition of 1 mol% Li_2O, electromechanical coupling factor (kp) and piezoelectric coefficient (d_(33)) of NK.N-5LT ceramics were found to reach the highest values of 0.37 and 250 pC/N, respectively.