Abstract
The microstructure of plasma sprayed coating of zirconia stabilized with 8wt% of yttria was analysed by the electrochemical technique. Porosity of 15.9% was mostly opened pores which consisted of cracks by cooling and the incomplete bonding of sprayed particles. The thermal properties of plasma sprayed coating of zirconia and NiCrAlY were studied by a laser flash method. The thermal conductivities measured were related to the microcracked structures described above. Also, thermal conductivities of the two-layer composites (the plasma sprayed coatings) were determined by the laser flash method using Bulmer's technique. The thermal contact resistance at the zirconia/SUS 304 interface showed a large amounts of scatter without NiCrAlY bond coating. This tendency was observed in the bonding strength of sprayed coatings. Namely, a better correlation between the thermal contact resistance and the bonding strength is obtainable.
