Effects of K/Na ratio on the phase structure and electrical properties of 0.98(KxNa1−x)NbO3–0.02BiScO3 lead-free ceramics

Lead-free piezoelectric ceramics 0.98(KxNa1−x)NbO3–0.02BiScO3 (0.98 KxN1−xN–0.02BS) (x = 0.30–0.60) doped with 0.8 mol% Mn were prepared by conventional solid-state sintering. The effects of K/Na ratio on the phase structure and electrical properties of the Mn doped 0.98 KxN1−xN–0.02BS (0.98 KxN1−xN–0.02BS–Mn) were mainly studied. It is experimentally demonstrated that the electrical properties strongly depend on K/Na ratio in the 0.98 KxN1−xN–0.02BS–Mn ceramics and when x = 0.45 the ceramics exhibit optimum electrical properties: d33 ∼ 308 pC/N, kp ∼ 0.495, ɛr ∼ 1577, tan δ ∼ 0.028. These results show that the 0.98 KxN1−xN–0.02BS–Mn ceramic with x = 0.45 is a promising lead-free piezoelectric material.