Effect of Wetting and Surface Phenomena on Development of Coatings in Thermal Spraying

Wetting between the spreading droplet and the substrate plays an important role in the droplet flattening because it affects not only the surface effects but also the contact thermal resistance at the splat-substrate interface which is an important parameter for the development of the coating structure. In this paper, analytical formulas are determined which show the influence of wetting phenomena on the thickness or the radius of the splash, on the pressure developed upon drop impact and on the splash porosity. An effect of surface tension on the flattening parameters is investigated. The results obtained show good agreement with the experimental data. Paper includes a German-language abstract.