On the Oxidation Products in Mg-Rich Primers: I. the Case of Pure Mg Pigment

Abstract

As a complement to the mechanism study of Mg-rich primer protecting aerospace Al alloys (especially AA 2024-T3) from corrosion, the oxidation products produced during Prohesion exposure as well as their distribution in primer films were analyzed by multiple surface analysis approaches. On cross-section samples prepared with a microtome technique, the major Mg oxidation/corrosion product was identified as hydromagnesite (Mg5(CO3)4(OH)2•5H2O) by XPS and Raman spectroscopy. Furthermore, through SEM and confocal microscopy, it was observed that the oxidation products were mainly accumulated in the voids presented in coating film. Based on these results obtained, the possible corrosion protection mechanism of Mg-rich primer was suggested.