Strong adhesion between metallic coatings and their substrate is critical for ensuring coatings' wear performance and durability in steel infrastructure, including pipelines. The thickness of metallic coatings can influence bonding performance. This study investigates the effect of substrate roughness and coating thickness on the interfacial bonding performance of wire-arc coatings, evaluated using Pull-Off Tensile and Portable Adhesion Tests. Three sizes of aluminum oxide grits were blasted to create fine (#240), medium (#54), and coarse (#12) substrate profiles. Al-arc coatings with 0.2, 0.3, and 0.4 mm thicknesses were sprayed on each surface. Each substrate's surface roughness was measured using a roughness tester and analyzed using Scanning Electron Microscopy (SEM). Results showed that thicker coatings on coarse and medium surfaces exhibited higher adhesive strength and strain values, while thinner coatings performed better on fine surfaces. SEM images of blasted profiles indicate higher hills and deeper valleys of coarse and medium grits, which provide more surface area to coatings, making stronger bonds. These findings offer valuable insights into optimizing the thermal spray coating process for pipeline applications.
Badin et al. (Thu,) studied this question.