Effect of the Bond Coating Surface Morphology on Ceramic Splat Construction

In this work, yttria-stabilized zirconia splats deposited onto different bond coatings were characterized. The influence of both substrate topography and temperature on splat morphologies was investigated. The substrate surface was described using a method characterized by multi-level roughness. On non-heated substrate, the peak-valley structure in scale of micrometer contributed to the formation of crater-like holes on splats. The amount of such holes was reduced with the increase of substrate temperature. It was also observed that on micro-smooth surface, island-like fragments in the center of splat would warp and their edges could be detached from the underlying substrate, especially when the substrate was heated. The obtained results reveal that the influence of substrate pre-heating on the splat formation is realized via thinning the air film near substrate surface.