Sintering Processing and Piezoelectric Properties of K0.5Na0.5NbO3-BiFeO3 Lead-free Ceramics

Leada2free BiFeO3 (BF) doped K0.5Na0.5NbO3 (KNN) piezoelectric ceramics were prepared by a traditional ceramic processing. The effects of sintering temperature and holding time on the microstructure, phase transition, density and piezoelectric properties of BF doped KNN ceramics were investigated. The results show that all specimens exhibit a pure perovskite structure. The surface micrograph, density and piezoelectric properties of the ceramics depend strongly on the sintering temperature and holding time. When being sintered at temperature from 1100 o 1150 or 3h, the d33, Kp and Qm of the ceramics increase, while the tan| decreases with the sintering temperature increasing. When being sintered at 1150 or 1h to 3h, the d33, Kp and Qm of the ceramics increase firstly and then remain unchanged, while the tan| decreases firstly and then also remains unchanged with the holding time increasing. The BFa2doped KNN ceramics sintered at 1150 or 2h exhibit excellent properties (| /EM>=4.50g/cm3￡ d33=132pC/N, Kp=45%, Qm=333.73, tan| /EM>=2.39%).