2024 aluminium alloy wettability and superficial cleaning improvement by air cold plasma treatment

2024 aluminium alloy is used for parts and structures which demand high-strength/weight ratio. In particular, Al2024 is, for its high specific strength and good chemical stability, a suitable material for aerospace application. Aluminium alloys are involved in corrosive phenomena when they are used in critical applications, such as the aeronautic ones. The solution commonly adopted to solve corrosive problems is to paint aluminium alloy surface including 2024 aluminium alloy which is the subject of this study. The applied paint film protects the aluminium alloy from corrosion. In order to improve the adhesion of the paint film it is necessary to pre-treat the manufactured surface. The objective of the pre-treatment is to develop a cleaned, uniform, wettable surface. Cold plasma is an efficient, economic and environmentally attractive alternative to the use of the traditional pre-treatment. This work aims to study the relationship between cold plasma and 2024 aluminium alloy wettability and cleaning. Surface samples have been analysed by: (i) standard procedure to measure the quantitative wettability; (ii) Energy Dispersive X-ray Spectroscopy or EDS to determine a quantitative measure of organic contaminant. This work demonstrates that air cold plasma treatment improves significantly wettability and cleaning of 2024 aluminium alloy surfaces both associated with pre-cleaning by MEK® and without pre-cleaning by MEK®: the wettability reducing has been greater than 70% and the contaminants reducing greater than 65%.