Effects of CuO doping on the electrical properties of 0.98K0.5Na0.5NbO3-0.02BiScO3 lead-free piezoelectric ceramics

CuO-doped 0.98K_0.5Na_0.5NbO₃-0.02BiScO₃ (0.98KNN-0.02BS-xCu) lead-free piezoelectric ceramics have been fabricated by ordinary sintering technique. The effects of CuO doping on the dielectric, piezoelectric, and ferroelectric properties of the ceramics were mainly investigated. X-ray diffraction reveals that the samples at doping levels of x ≤ 0.01 possess a pure tetragonal perovskite structure. The specimen doped with 1 mol% CuO exhibits enhanced electrical properties (d₃₃ ~ 207 pC/N, k_p ~ 0.421, and k_t = 0.424) and relatively high mechanical quality factor (Q_m = 288). These results indicate that the 0.98KNN-0.02BS-0.01Cu ceramic is a promising candidate for lead-free piezoelectric ceramics for applications such as piezoelectric actuators, harmonic oscillator and so on.