Reactivity classification in saline solution of magnetron sputtered or EBPVD pure metallic, nitride and Al-based alloy coatings

In this study, various metallic or nitride coatings elaborated by Electron Beam Physical Vapour Deposition (EBPVD) or magnetron sputtering techniques are characterised in terms of mechanical properties and corrosion behaviour in saline solution. The incorporation of transition metals permits to modify the mechanical or physico-chemical characteristics of aluminium coatings, so several alloying elements are compared. These alloys are also compared with pure metallic coatings and/or coatings synthesized by reactive magnetron sputtering. Evolution of microstructure of the Al based coatings was discussed versus the alloying element content. Different compositions of alloys were examined. This paper presents the synthesis of the main tendency reported during the evaluation of the mechanical and corrosion properties of these alloys.The objective is to build a reactivity classification in saline solution of several Al based coatings synthesized by vacuum deposition techniques. Combined with the classification of mechanical properties, these standards would become relevant guides in the choice of PVD coatings and/or alloys for applications exposed to saline environments. In our study, this guide is helpful in the synthesis of nanometric multilayer architectures, which proves to be a promising way to combine improved mechanical properties with sacrificial character for the future coating configurations.

► Morphological and structural characterisation of metals and alloys deposited by PVD. ► Electrochemical reactivity of Al-based alloys in saline solution. ► Influence of incorporation of transition metals on the pitting corrosion of aluminium. ► Reactivity classification of Al coatings deposited by vacuum deposition techniques. ► Classification of mechanical properties in terms of micro-hardness measurements.