Effect of Sr and Ba-doping in optical and electrical properties of KNN based transparent ceramics

摘要

Sr~(2+)/Ba~(2+) modified potassium sodium niobate transparent ceramics [(K_(0.5)Na_(0.5))_(1_2x)(Sr_(0.75)Ba_(0.25))_x]_(0.93) Li_(0.07)Nb_(0.93)Bi_(0.07)O_3 (KNNLB:Sr~(2+)/Ba~(2+)) were fabricated via hot-pressing, using Li and Bi as sintering aids. The crystal structure, microstructure, optical, piezoelectric and dielectric properties of KNNLB with varied Sr~(2+)/Ba~(2+) content were investigated. The optical transparency of such ceramics is up to 60 % in the UV-visible region and close to 100 % in the infrared region. Moreover, the optimum dielectric and piezoelectric performances of ε_r = 1679, d_(33) = 151 pC/N and tanδ = 0.026 were obtained for KNNLB:Sr~(2+)/Ba~(2+) ceramics with x = 0.025. Consequently, the doping of Sr~(2+)/Ba~(2+) is considered as an effective way to improve electrical properties and maintain excellent optical properties of the fine-grain transparent ceramics.