Lead-free NKN-5LT piezoelectric materials for multilayer ceramic actuator

As a candidate for lead-free piezoelectric materials, Li(2)O excess 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(2)O as a sintering aid. Abnormal grain growth in NKN-5LT ceramics was observed with varying Li(2)O content. In the 1 mol% Li(2)O excess NKN-5LT samples sintered at 1000A degrees C for 4 h in air, electromechanical coupling factor and piezoelectric constant of NKN-5LT ceramics were found to reach the highest values of 0.37 and 250 pC/N, respectively. Lead-free piezoelectric ceramic, Li(2)O excess NKN-5LT, multilayer ceramic actuators (MLCA) were fabricated. 10 x 10 x 1 mm(3) size MLCAs were fabricated by conventional tape casting method. The displacement of Li(2)O excess NKN-5LT MLCA with 3 mm thickness was similar to 1 mu m at 150 V.