'ELECTROLESS' E-COATING FOR MAGNESIUM ALLOYS

摘要

By utilizing the unique electrochemistry of Mg, a thin organicfilm can rapidly be deposited on the surface of a Mg alloy bydipping the Mg alloy in a cathodic E-coating bath solution withoutapplying a current or potential. The self-deposited coating isselectively formed on Mg alloy surfaces. Although the“electroless” E-coating pre-film is relatively thin, it can offersufficient corrosion protection for Mg alloys in a chloridecontainingenvironment. The stability of the film can besignificantly improved after curing. The corrosion resistance ofthe substrate Mg alloy has an important effect on the corrosionprotection performance of the coating. The coating is moreprotective on a corrosion resistant Mg alloy than on a noncorrosionresistant Mg substrate. The coating protectionperformance is also influenced by the substrate surface conditionor pre-treatment process. Wet cleaning + heat-treatment may be acost-effective surface preparation/treatment for the “electroless”E-coating in industrial applications.