Corrosion resistance of PEO and primer coatings on magnesium alloy

Abstract

In recent years, magnesium alloys have become a subject of interest in many industrial sectors, e.g. the automotive and aircraft industries as well as biomedical and mechanical engineering. Magnesium alloys belong to the group of the lightest alloys of non-ferrous metals. Therefore, their application in the aircraft industry is a very desirable solution. The innovative combination of a composite layer with carbon fibers in aviation on the same principle as fiber metal laminates encourages thorough analysis of the corrosive behavior of the connection of two chemically different materials. As is known, such a connection is greatly exposed to corrosion, especially galvanic, between its components. Therefore, the corrosion behavior of the magnesium alloy with a protective coating must first be examined before joining with the CFRP layer. The present article is the first one in a series of analyses carried out in order to evaluate the corrosion resistance and behavior of the AZ31 alloy with plasma electrolytic oxidation (PEO) and a primer in an NaCl solution. Those results show that among Mg/PEO, Mg/Primer and Mg/PEO/Primer has the best corrosion resistance due to Mg/PEO/Primer possess the PEO and primer layer simultaneously.