The Effect of Dopants on Sintering and Microstructure of Lead-free KNN Ceramics

  • Ilze SMELTERE University of Latvia, Riga Technical University
  • Maija ANTONOVA University of Latvia
  • Anna KALVANE University of Latvia
  • Oskars GRIGS Riga Technical University
  • Maris LIVINSH University of Latvia
Keywords: potassium sodium niobate, lead-free, oxide additives, piezoelectric ceramics, sintering


Lead-free potassium sodium niobate (K0.5Na0.5)NbO3 (KNN) has been prepared via conventional ceramic processing method. The influence of 0.5 wt% - 1.5 wt% MnO2 and WO3 addition on the sintering, crystallographic structure, microstructure and dielectric properties of KNN has been investigated. Optimal sintering temperatures of KNN ceramics were observed to be in the narrow interval: 1090 °C - 1110 °C for MnO2 doped KNN; 1150 °C - 1170 °C for pure KNN and doped with WO3. XRD patterns showed that all the samples have single perovskite structure with monoclinic structure. Microstructure of ceramics was changed greatly by using dopants.