Screening the effect of chemical treatment of steel substrate by a composite cerium-lanthanum nanofilm on the adhesion and corrosion protection properties of a polyamide-cured epoxy coating; Experimental and molecular dynamic simulations

The steel substrate was treated by cerium-lanthanum based conversion coatings. The effects of surface treatment of steel on the interfacial adhesion, cathodic delamination and corrosion resistance of the epoxy coating were studied through experimental and computational studies. Corrosion resistance of the epoxy coating applied on the untreated and surface treated samples was evaluated by electrochemical impedance spectroscopy and salt spray test. Results of experiments revealed that post-treatment of cerium conversion coating by lanthanum gave rise to the superior corrosion resistance, low cathodic delamination rate and enhanced interfacial adhesion of the epoxy coating, in agreement with computational results. In addition, computational molecular dynamic (MD) simulations revealed that the epoxy bonding to the steel surface was remarkably enhanced by surface treatment of steel substrate by cerium conversion coating post-treated by lanthanum.