Thermal conductivity of a ZrO2-Ni functionally graded coatings

A Ni-ZrO2 (3 mol.% Y2O3) functionally gradient (FG) coating and a pure ZrO2 coating, both having thickness of around 200 μm, were prepared over nickel substrates. The thermal conductivity of these model coatings was evaluated by laser-flash measurements done on both assemblies and in the Ni substrate as well. A simple model is proposed to estimate the thermal conductivity of each layer of the FG coating, which gives a good estimation for the thermal conductivity of the FG coating.