Ca_0.5Sr_0.5TiO₃-Modified KNN-Based Lead-Free Piezoceramics with a Wide Temperature Usage Span

The strong temperature dependence of dielectric and piezoelectric properties is a big 'bottleneck' for practical applications of KNN-based piezoceramics. In order to resolve this problem, Ca_0.5Sr_0.5TiO₃ (CST) is doped into (Na_0.53K_0.407Li_0.063)Nb_0.937Sb_0.063O₃ (NKLNS) ceramics. The thermal stability of s₁₁^E and k₃₁ in the temperature range from −50°C to 200°C for ceramics with 1.0 and 1.5 mol% CST is raised in comparison with ceramics without CST. Ceramics with 1.5 mol% CST exhibit high piezoelectric properties (d₃₃=202 pC/N, k_p=44%) and low dielectric loss (2%) at room temperature. The excellent piezoelectric properties, which are comparable to conventional PZT ceramics, indicate that these ceramics are promising candidates for lead-free piezoelectric applications.