A Study on the Effect of Surface Profile on Pull-off Adhesion Strength Value of Organic Coatings

Pull-off adhesion testing is a commonly used method to determine the coating adhesion strength. Relying on the pull-off adhesion testing technique to determine the coating adhesion strength is increasingly common due to its quantitative result. This study focuses on how the pull-off adhesion strength value of the coating is affected by the change in critical factors i.e. surface profile morphology (spherical, sharp & angular) and a range of surface roughness profile height (μm). Test sample surface was prepared to visually clean steel with diverse sizes and shapes of abrasives, coated with a 3 coat system. Pull-off adhesion testing was performed on the fresh coating and after exposing the coating to cyclic ageing test conditions adopted from ISO12944-9, Annex B. Additionally, electrochemical impedance spectroscopy (EIS) and surface characterization of abrasives using scanning electron microscopy (SEM) and cross sectional analysis of coating sample after ageing with SEM-EDS (Scanning electron microscopy-Energy dispersive spectroscopy) were also performed.