Comparative study of the alloying effect on the initial oxidation of Cu-Au(100) and Cu-Pt(100)

Using in situ transmission electron microscopy, we show that the oxidation of the Cu-Au(100) results in the formation of Cu2O islands that deeply embed into the Cu-Au substrate while the oxidation of the Cu-Pt(100) leads to the formation of Cu2O islands that highly protrude above the Cu-Pt substrate. Their difference is attributed to the different mobilities of Pt and Au in the Cu base alloys for which the sluggish mobility of Pt in Cu results in trapped Pt atoms at the oxide/alloy interface while the faster mobility of Au in Cu leads to enhanced rehomogenization of the alloy composition. (C) 2014 AIP Publishing LLC.