Anisotropic effect of splat interface on thermal conductivity of plasma sprayed YSZ coating

Based on manually processing of the fracture surface, a novel method has been developed to extract the distribution feature of splat interfaces of plasma sprayed coatings. Through characterizing the porous structure and splat interface distribution of coating, a coupled finite element model was established to predict the anisotropic thermal conductivity of YSZ coating. Based on theoretical and experimental analysis, the thermal conductivity of splat interface was determined to be 0.12. W/mK. A comparison between the coefficients of splat interfaces and pores shows that splat interfaces contribute more for the thermal conductivity reduction in through-thickness direction than pores, while contribute equivalently in in-plane direction. Above results indicate that the splat interface is a key factor that determine the anisotropic thermal conductivity of plasma sprayed coating.