Effect of Substrate Temperature and Roughness on Coating Formation

Though a large literature exists on thermal spray coating, there have been few attempts to directly observe molten droplets as they land on a substrate, freeze, and coalesce into a solid layer. In this study, investigators photograph the impact of tin droplets landing on stainless steel surfaces at high speeds. They also measure the effect of substrate temperature and surface roughness on deposition efficiency, the fraction of coating material that adheres to the surface. The paper describes the apparatus used to create the tin droplets and record their impact with the target. It also provides a detailed review of the test results and discusses the practical implications of the study. Paper includes a German-language abstract.