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

Lead-free potassium sodium niobate (K(0.5)Na(0.5))NbO(3) (KNN) has been prepared via conventional ceramic processing method. The influence of 0.5 wt% - 1.5 wt% MnO(2) and WO(3) 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 degrees C - 1110 degrees C for MnO(2) doped KNN; 1150 degrees C - 1170 degrees C for pure KNN and doped with WO(3). XRD patterns showed that all the samples have single perovskite structure with monoclinic structure. Microstructure of ceramics was changed greatly by using dopants.