Adhesion of a protective coating on a surface of aluminium alloy treated by air cold plasma

Abstract 2024 aluminium alloy is subjected to severe conditions and heavy stresses when they constitute the structure of an aircraft or an helicopter; for this reason, it is commonly protected by a paint coating. When this paint coating is applied, two elements are essential—the wettability and the activation of the surface to be coated. Currently at industrial level a complex and critical process is used to enhance the wettability and the activation of aluminium alloy surfaces. Cold plasma represents an efficient, non-polluting and economical alternative to clean, activate and, then, to increase the adhesive properties of aluminium surfaces. In order to improve adhesive properties of 2024 aluminium alloy surfaces, the present work evaluates the possibility that cold plasma treatment becomes part of the traditional process up to substitute one or more of its steps. This work deals with mechanical tests that are commonly used in the aeronautical industry to analyze adhesion. These tests stand for the minimum conditions the coated aluminium should pass to operate in a non-aggressive atmosphere. The results obtained by cold plasma have been compared with those due to the industrial activation process.