To study the physical origin of the non-ohmic behavior of WO3 ceramics,the effects of heat treatment in different atmospheres on WO3 varistors were investigated.Experiments showed that there was a dependence of the no...To study the physical origin of the non-ohmic behavior of WO3 ceramics,the effects of heat treatment in different atmospheres on WO3 varistors were investigated.Experiments showed that there was a dependence of the nonlinear coefficient on thermal treatment under different atmospheres.Thermal treatments in argon and oxygen atmospheres at 900℃proved this dependence,and indicated that the nonlinear coefficient got significantly lower when the samples were thermally treated under argon atmosphere.Subsequent exposure to oxygen atmosphere at the same temperature led to the restoration of electrical properties.The result shows that the physical origin of the non-ohmic behavior of WO3 ceramics is oxygen on the grain surfaces adsorbed by intrinsic defects.展开更多
基金supported by the National Natural Science Foundation of China(No.50772092)
文摘To study the physical origin of the non-ohmic behavior of WO3 ceramics,the effects of heat treatment in different atmospheres on WO3 varistors were investigated.Experiments showed that there was a dependence of the nonlinear coefficient on thermal treatment under different atmospheres.Thermal treatments in argon and oxygen atmospheres at 900℃proved this dependence,and indicated that the nonlinear coefficient got significantly lower when the samples were thermally treated under argon atmosphere.Subsequent exposure to oxygen atmosphere at the same temperature led to the restoration of electrical properties.The result shows that the physical origin of the non-ohmic behavior of WO3 ceramics is oxygen on the grain surfaces adsorbed by intrinsic defects.
