Correlation between pull-off strength of thermallysprayed coatings and substrate topography

One of the most important assessment criterions of thermally sprayed coatings is pull-off strength. High pull-off strength generally requires a rough and uncontaminated surface. Prior to the coating process, the substrate surface is roughened and cleaned using grit blasting to activate the surface. Different blasting parameters cause differences in the surface topography, which results in a variation of the pull-off strength of the coating. In this paper, surface parameters will be determined which shows a better linear correlation with the pull-off strength than the widely used parameters Rz or Ra.