Influence of DLC Film Deposition on the Corrosion and Micro-abrasive Wear Tests of the 2524-T3 Al Alloy

Abstract

The 2524-T3 aluminium (Al) alloy produced by ALCOA may be used as skin material by the aircraft industry. Some studies are available in the literature about fatigue and fatigue - corrosion behaviour of 2524-T3 Al alloy. However, the corrosion mechanisms are not yet fully understood since the material has a very complex microstructure due to impurities and the addition of alloying elements which lead to an increase in the localized corrosion process. It is known that the corrosion process in Al alloys, most of the time, is due to the galvanic coupling of the intermetallic particles (IMs) and the Al matrix. Thus, the use of protective coatings appears as a possible alternative against the advancement of the corrosion process of the 2524-T3 alloy. In this way, a set of DLC films was obtained by using physical vapor deposition (PVD) method and characterized by various techniques including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Atomic force microscopy (AFM) and Raman spectroscopy. The deposited films on the surface of the 2524-T3 Al alloy were characterized electrochemically by using potentiodynamic polarization curves (PPc), electrochemical impedance spectroscopy (EIS) and mechanically by using micro-abrasive wear tests (MAWTs). The results show an advantage in using the PVD method to produce thin films on the 2525-T3 Al alloy surfaces, as the wear resistance of the Al alloy coated by DLC film is higher than for the bare material and the corrosion resistance of the material is not compromised. DOI: http://dx.doi.org/10.17807/orbital.v11i2.1321