Improved Corrosion Protection of Aluminum Alloys by System Approach Interface Engineering: Part 2—AA2024-T3

Abstract

Abstract This study investigates the development of a chromate-free corrosion protection system for AA2024-T3 ([2B]) based on the concept of system approach interface engineering (SAIE) by chemical and plasma techniques. An anode magnetron-enhanced direct current (DC) cathodic plasma process was used to enhance the bonding to and the protection offered by a cathodically electrodeposited epoxy-based primer (E-coat) on [2B]. Corrosion test results of SO2 and Prohesion salt spray tests indicated that superior corrosion protection properties of [2B] were achieved with the aid of plasma interface engineering, tailoring specific properties of the interfaces. Many of these plasma polymer-enhanced systems on [2B] outperformed the controls used in this study: chromate conversion coated and then primer (Deft 44-GN-36) coated [2B], as well as chromate conversion coated and then cathodic E-coated [2B]. The corrosion protection properties of [2B] were strongly dependent on the surface preparation of the alloy, which was investigated by x-ray photoelectron spectroscopy (XPS). Plasma polymer-coated systems prepared on alkaline-cleaned [2B] surfaces displayed enhanced corrosion protection properties.