Piezoelectric Properties and Moisture-Resistance of Glass Added K0.5Na0.5NbO3

We investigated the effect of piezoelectric properties and moisture-resistance of K0.5Na0.5NbO3 ceramics by adding glass. The addition of 1wt.% ZnO- based glass exhibited the following piezoelectric properties (kp = 36%, Qm = 236, ε33T/ε0 = 464) and the relative density was 97.28%. By increasing the amount of glass powder ∼5wt.%, kp was decreased to 24%. However, Qm and ε33T/ε0 were observed slightly decreasing. In this study, we added ZnO-based glass to K0.5Na0.5NbO3 to test the moisture-resistance reliability caused by deliquescence in a high heat, high humidity experiment and to find ways of improving moisture-resistance reliability. As the cause of enhancing moisture-resistance, we considered that the glass was covered the surface of the K0.5Na0.5NbO3 phase, because the glass phase was confirmed as existing in the grain boundary by EPMA element mapping analysis. And the same effects were confirmed by adding other glass to K0.5Na0.5NbO3.