Demonstration of epoxy/carbon steel interfacial delamination behavior: Electrochemical impedance and X-ray spectroscopic analyses

• Carbon steel surface was modified chemically using acid and alkaline solution.
• Oxide surface morphology and chemistry were studied.
• XPS has been used to evaluate the residue bondings on the metal surface.
• The interfacial bonding stability of the differently treated samples has been investigated.
• An improved protection against corrosion was observed for the acid treated samples.

In this work, we introduce an efficient methodology to assess the delamination mechanism of epoxy coating from steel substrate combining spectroscopic and analytical techniques. To reflect the competence of this approach, different samples were prepared by applying epoxy/polyaminoamide layers on untreated, acid and alkaline pretreated substrates. The results obtained from XPS and energy dispersive X-ray analyses describe delamination of the coatings on differently pretreated surfaces during the pull-off test. EIS measurements demonstrated that acid treatment improves the resistance against cathodic delamination, while XPS analysis provided useful data about coating delamination from the substrate.