Abstract
This paper describes an experimental study of the influence of steel surface roughness on the performance of a fusion bonded epoxy (FBE) pipeline coating. Steel panels were abrasive blast cleaned with various steel shot and grit abrasives. The roughness characteristics of the blast cleaned surfaces were measured with a stylus profilometer, replica tape per NACE SP0287, and a digital replica tape reader. The 3D topographical data files generated by the digital tape reader were interpreted using surface analysis software. A FBE pipeline coating was applied to the prepared steel panels and the performance of the coating was evaluated using pull-off adhesion strength, cathodic disbondment and Atlas cell wet thermal gradient tests. The strength of correlations among the roughness parameters and the FBE coating performance results were compared. Tortuosity, measured with a stylus profilometer, and developed interfacial area (Sdr), measured with the digital replica tape reader, were found to be strongly correlated with FBE coating performance. The findings of this study suggest that the increase in real surface area developed by roughening the surface is a fundamental roughness characteristic that strongly influences coating adhesion performance.
