Reactivity of transition-metal alloys to oxygen and sulphur

Oxidation and tarnishing are the two most common initial steps in the corrosive process of metals at ambient conditions. These are always initiated with O and S binding to a metallic surface, so that one can use the binding energy as a rough proxy for the metal reactivity. With this in mind, we present a systematic study of the binding energy of O and S across the entire transition-metals composition space, namely we explore the binding energy of 88 single-phase transition metals and of 646 transition-metal binary alloys. The analysis is performed by defining a suitable descriptor for the binding energy. This is here obtained by fitting several schemes, based on the original NewnsAnderson model, against density-functional-theory data for the 4d transition metal series. Such descriptor is then applied to a vast database of electronic structures of transition-metal alloys, for which we are able to predict the range of binding energies across both the compositional and the structural space. Finally, we extend our analysis to ternary transition-metal alloys and identify the most resilient compounds to O and S binding.