SnO_2-Co_2O_3-Nb_2O_5-Y_2O_3陶瓷的微结构和不同温度下的电学特性

Microstructure and Effects of the Temperature on the Electrical Properties of SnO_2-Co_2O_3-Nb_2O_5-Y_2O_3 Ceramics

用常规的陶瓷工艺制备SnO2-Co2O3-Nb2O5-Y2O3陶瓷. 采用XRD、SEM来对陶瓷的微结构进行表征,详细研究了温度对陶瓷电学行为的影响. 结果表明:烧结的陶瓷结构致密,在陶瓷样品中,除了SnO2相之外,没有发现其他相,在晶粒与晶粒之间没有观察到明显的晶粒层. 在直流电条件下,陶瓷具有明显的稳定的变阻器行为,随着温度的升高这种行为减弱,电导率增大,表现出半导体行为. 这些事实可以归因于陶瓷中的固熔体和晶格中各种缺陷的形成.

SnO2-Co2O3-Nb2O5-Y2O3 ceramics was obtained by using conventional ceramic technology. The microstructure of the ceramics was characterized by X-Ray Diffraction(XRD) and Scanning Electron Microscopy(SEM) analysis. At the same time, the effects of the temperature on the electrical properties of the ceramics were investigated at length. The results indicate that the sintered ceramic has very high density,reaching 94.9% of the theoretical density, no secondary phase but only the SnO2 phase was detected in the ceramics and the distinct grain boundary layers were not observed yet. Under the DC. conditions, the ceramics exhibited obvious nonohmic property and the conductivity drastically increased with the temperature rising but the nonlinear coefficient became weak. The formation of the solid solution and all kinds of defects in the ceramics should be responsible for these facts.