ZnO压敏陶瓷反射光谱的研究

利用简便的粉末反射光谱法，测量了不同烧结温度下ZnO压敏陶瓷的反射光谱，并对其影响机理进行了探讨．研究结果表明，同纯ZnO相比，压敏陶瓷反射光谱吸收边发生红移，红移量随烧结温度的提高而增大；吸收边斜率随着烧结温度升高而变小．吸收边的变化是烧结过程中ZnO晶粒表面包覆程度和元素相互扩散随温度变化的结果．高温烧结的试样在波长为566nm、610nm、650nm处存在光反射谷，反射强度随烧结温度升高而降低．烧结过程中形成的界面层缺陷是反射谷形成的主要原因，缺陷类型与温度变化无关，浓度随烧结温度的升高而增大．

Reflection Spectra Studies on ZnO Varistors

The reflection spectra of ZnO varistors at different sintering temperature were investigated by simple powder reflection method. The influence mechanism of the temperature on reflection spectra was discussed. Compared with the pure ZnO, the absorption edge from reflection spectra is shifted to longer wavelength. As the sintering temperature increases, the red shift increases and the steepness factor of absorption edge decreases, because the sintering temperature has influence on the surface capping of ZnO grain and the diffusion of components. Three reflection valleys at 566, 610, and 650nm were observed for the samples heated at high temperature. The reflection intensities of the valleys decrease as the sintering temperature increases, corresponding to the defects in the interface layer that were formatted during the sintering procedure. The defect category is independent of the sintering temperature, but the concentration increases as the sintering temperature increases.