Piezoelectric Properties and Microstructures of $Li_2O$ excess $(Na_{0.47}K_{0.47}Li_{0.06})NbO_3$ Ceramics

$Li_2O$ 첨가에 따른 $(Na_{0.47}K_{0.47}Li_{0.06})NbO_3$ 세라믹스의 압전특성과 미세조직의 변화

As a candidate for lead-free piezoelectric materials, dense ($(Na_{0.47}K_{0.47}Li_{0.06})NbO_3$ (LNKN6) ceramics were developed by conventional sintering process. Sintering temperature was lowered by adding $Li_2O$ as a sintering aid. Abnormal grain growth in the LNKN6 ceramics was observed with varying $Li_2O$ content. The electrical properties of LNKN6 ceramics were investigated as a function of $Li_2O$ concentration. When the sample sintered at $1000^{\circ}C$ for 4h with the addition of 1 mol% $Li_2O$, electromechanical coupling factor ($k_p$) and piezoelectric coefficient ($d_{33}$) of LNKN6 ceramics were found to reach the highest values of 0.40 and 184 pC/N, respectively.