The effect of titanium dioxide and molybdenum oxide on the properties of sodium potassium niobate piezoceramic

Sodium potassium niobate piezoceramics are considered as lead-free piezoelectric due to their good properties. In this study, the effect of titanium dioxide and molybdenum oxide as dopant on the densification behavior, piezoelectric and dielectric properties of lithium doped sodium potassium niobate ((K0.5Na0.5)0.94Li0.06NbO3, KNNL) was investigated. For this purpose, (K0.5Na0.5)0.94Li0.06Nb0.99X0.01O3 (KNNL-X, X= Mo, Ti) ceramics were synthesized by solid state reaction method. The results showed that the use of these dopants improves the densification of KNNL ceramic, which could be attributed to the increased diffusion due to creating the oxygen vacancy defect. The decrease in the piezoelectric coefficient of KNNL ceramic in the presence of dopants can be attributed to the hardening behavior of the piezoceramic due to the existence of oxygen vacancies. The increase in dielectric constant and decrease in dielectric loss of doped samples can be attributed to the increase in density and decrease in porosity. KNNL-Mo samples showed the lowest piezoelectric coefficient and the highest dielectric constant values.