EFFECT OF NiO ADDITIVE ON STRUCTURE AND DIELECTRIC PROPERTIES OF Bi_2O_3-ZnO-Nb_2O_5 BASED CERAMICS

摘要

The effect of NiO additive on structure and dielectric properties of Bi_2O_3-ZnO-Nb_2O_5 based ceramics was investigated. All the samples were obtained at lower sintering temperature between 960 deg C approx 1020 deg C. With the aids of XRD analyses the structure of these samples was recognized. It shows that although the structure at small amount additive (NiO<=2 wt percent) is still made of cubic pyrochlore #alpha# phase and monoclinic pyrochlore #beta# phase as that of the reference composition, the proportion of each phase has been changed. With increasing of NiO doping, dielectric constant and loss rises at room temperature, and temperature coefficient of dielectric constant is declined to negative. The result of dielectric behaviors indicates that certain NiO additive can be an effective way to improve the value of dielectric constant and adjust temperature coefficient in Bi_2O_3-ZnO-Nb_2O_5 based ceramics.