Plasma-Driven Surface Functionalization: Enhancing the Corrosion Resistance of Aluminum via Atmospheric-Pressure Treatment

Aluminum and its alloys are employed in different industries due to their versatile properties (low density, resistance to corrosion, thermal conductivity). However, the corrosion properties of these alloys can be enhanced through protection methods. In this paper, the effect of surface treatment through atmospheric pressure plasma on the corrosion properties of a 6061 aluminum alloy was evaluated. The corrosion resistance was evaluated using electrochemical impedance spectroscopy. The jet-substrate distance and number of passes were selected as the plasma process parameters. The plasma treatment allowed the formation of a passive layer that exhibits higher corrosion resistance than the untreated substrate, corresponding to an increase of nearly three orders of magnitude in polarization resistance. Further, the passive layer's morphological characteristics and chemical composition were analyzed through scanning electron microscopy with energy dispersive spectroscopy, optical profilometry, and X-ray photoelectron spectroscopy, where an increase of around 40% in oxygen content supports the presence of an oxygen-rich layer on the surface.