ELECTRICAL AND THERMAL-CONDUCTIVITIES OF NICKEL-ZIRCONIA CERMETS

The microstructure, electrical resistivity, and thermal diffusivity of nickel-zirconia cermets have been studied. Scanning electron microsco py of the fracture surfaces of samples shows that there are some small isolated nickel granules adhering to the surface of the zirconia part icles. Considering such a microstructural feature of samples and the l aw of mixtures, an improved model for electrical and thermal conductiv ity is established. With this model, the experimental results-that ele ctrical conductivity and thermal diffusivity increase with increasing nickel content-are interpreted. Moreover, the thermal diffusivity is o bserved to be almost linearly related to temperature.