用正电子湮没研究铌掺杂效应氧化锌导电陶瓷的结构缺陷

Structural Defect Study of ZnO Conductive Ceramics Doped Niobium by Positron Annihilation

用正电子湮没技术，结合扫描电子显微镜结构分析，研究掺杂Nb2O5的ZnO导电陶瓷掺杂含量、烧结温度和烧结时间对材料结构的影响。结果表明正电子会被锌空位和微空洞缺陷捕获。随着Nb2O5含量的增加，晶界上单位体积VZa数量增多。随烧结温度升高，晶界层VZn浓度增加，ZnO界面微空洞缺陷减小，材料变得致密。随烧结时间增加，VZa增加不明显，ZnO界面微空洞缺陷增大，材料变得疏松。

The effects of additive contents, sintering temperature and time on structural characteristics of ZnO conductive ceramic materials doped with Nb2O5 are investigated by use of positron annihilation and scanning electron microscope analysis. It is found that positron at the grass- boundary can be trapped by zinc vacancies and vacancy defect. The number of zinc vacancy is increased with the increase of Nb2O5 content. Vacancy defect concentration is decreased with the increase of the sintering temperature and the scale of the vacancy defect is reduced and the material is densified. The number of vacancy defect is not obviously varied with the increase of the sintering time, but the scale of the vacancy defect is increased and the material looses.