Electrical and Thermal Conductivities of Nickel‐Zirconia Cermets

The microstructure, electrical resistivity, and thermal diffusivity of nickel‐zirconia cermets have been studied. Scanning electron microscopy of the fracture surfaces of samples shows that there are some small isolated nickel granules adhering to the surface of the zirconia particles. Considering such a microstructural feature of samples and the law of mixtures, an improved model for electrical and thermal conductivity is established. With this model, the experimental results‐that electrical conductivity and thermal diffusivity increase with increasing nickel content‐are interpreted. Moreover, the thermal diffusivity is observed to be almost linearly related to temperature.