Effects of Sintering Temperature on the Microstructure and Electrical Properties of BiMnO3-Doped 0.95Na0.5K0.5NbO3-0.05LiSbO3 Ceramics

Lead-free 0.95K0.5Na0.5NbO3-0.05LiSbO3 (KNN-LS) ceramics doped with 0.2mol% BiMnO3 (BM) have been prepared by the conventional mixed-oxide technique, with sintering temperature at 1095-1120 degrees C. Microstructural and compositional analyses of these doped ceramics have been carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of the sintering temperature on the microstructure and piezoelectric and dielectric properties of BM-doped KNN-LS ceramics have been investigated. The results show that initially increasing the sintering temperature is very effective in improving the density and electric properties. However, the properties of the samples would be deteriorated as they are sintered over the optimum temperature. The KNN-LS-0.2% BF ceramics show excellent properties of d33=208pC/N, kp=43%, Qm=65, tan=2.78%, and Tc=385 degrees C with sintering temperature at 1110 degrees C.