Characterisation of corrosion products formed on PVD in situ mechanically worked Mg-Ti alloys

Mg-Ti alloys with up to 46 wt.% Ti in solid solution, produced by PVD processing with in situ mechanical working, were subjected to immersion tests in 3 wt.% NaCl solutions. The corrosion resistance of the alloys, assessed with gravimetric tests, was inferior to that of PVD pure Mg. Corrosive attack was favoured at the sites of mechanical working owing to the different microstructure and the higher Mg concentration at these areas. The corrosive attack resulted in exfoliation of the alloys. The corrosion product contained a mixture of MgO, TiO2 and some Mg(OH)2 at the outermost surface. Although Ti participation in the corrosion products was enhanced, its beneficial affect was overshadowed by the defective nature of the deposits. The surface chemistry of the alloys was studied using the Auger parameter.