Investigation of nano particle additives on lithium doped KNN lead free piezoelectric ceramics

Lead free potassium sodium niobate modified piezoelectric ceramics were synthesized through conventional mixed oxide method. Crystal structure and microstructure were analyzed by X-ray diffraction and scanning electron microscopy (SEM). The effects of nano ZnO, CuO and SnO2 additives as the nano scale sintering aids, on microstructure and electrical properties of (K050Na0.50)0.94Li0.06NbO3 (KNNL-6) ceramics were investigated. The optimum dielectric and piezoelectric properties of ɛr = 560, d33 = 215 pC/N and tan δ = 0.008 were obtained for pure KNNL-6 that sintered at 1000 °C for 2 h. The results show that with addition of nano particle sintering aids, the piezoelectric coefficient d33 of (K050Na0.50)0.94Li0.06NbO3 ceramics was decreased. The decrease in piezoelectric charge coefficient could be due to the hardening effect, which lowers the piezoelectric charge.