Alkali volatilization of (Li,Na,K)NbO₃-based piezoceramics and large-field electrical and mechanical properties

Abstract

While lead-free (Li,Na,K)NbO₃ piezoceramics have a high Curie temperature (T_C > 400 °C) and an excellent piezoelectric constant (d₃₃ > 200 pC/N), the process window regarding the sintering temperature and dwelling time is narrow. Inappropriate sintering conditions can induce the volatilization of A-site alkali ions, leading to a deterioration in dielectric and piezoelectric properties. However, the effect of alkali volatilization on the ferroelastic properties is still uncertain. In this study, (Li,Na,K)NbO₃ piezoceramics were deliberately exposed to the sintering temperature for varying times to compare the susceptibility of the effect of alkali volatilization on the ferroelastic properties and compared to changes in the ferroelectric and ferroelastic and dielectric properties.