Corrosion Prevention by Applied Coatings on Aluminum Alloys in Corrosive Environments

摘要

In this study, the corrosion resistance of selected aluminum alloys with various combinations ofcommercial coatings was investigated using the Tafel electrochemical method in water and simulatedsalt water environments. The microtopography of the surfaces of the metals and applied coatings wastested using atomic force microscopy (AFM) and optical microscopy (OM) analysis. The combinationof an environmentally friendly electrodeposited ceramic coating with a primer and topcoat, whichresults in a chromium-free coating, exhibited a higher polarization resistance and a lower corrosionrate than the traditional chromate conversion coating combination. Coating defects and pores, whichwere revealed by the AFM images, were demonstrated to contribute to higher corrosion rates.