Microstructure and electrical properties of (K0.48Na0.52)0.97Li0.03NbO3 - 0.03CaZrO3 lead-free piezoceramics with (4CuO–TiO2–2Nb2O5) additive

Abstract 4CuO–TiO2–2Nb2O5 (CTN)-modified (K0.48Na0.52)0.97Li0.03NbO3- 0.03CaZrO3 (KNLNCZ-xCTN, x = 0.0, 0.5, 1.0, 1.5) lead-free piezoelectric ceramics were prepared using a conventional solid-state method. It is found that the addition of CTN could broaden the sintering window and suppress the abnormal grain growth of the sintered ceramics. The XPS results revealed that the Cu ions seem to be in the monovalent state at the ceramics inside and the Cu+ ions couldn't induce the hardening effect due to the equivalent replacement of Cu+ ions for Na+ ions. As a result, the well-saturated P-E loops and improved piezoelectric properties were obtained in the samples and the KNLNCZ-1.0CTN ceramic showed the optimal values with d33 = 131 pC/N, d 33 ∗ = 303 pm/V, kp = 0.43, and tanδ = 0.009. Meanwhile, the good temperature stability of the strain in the range of 20–80 °C was also achieved.