comparison between the effectiveness of corrosion inhibitors with distinctive molecular structures in film formation and corrosion inhibition of AA2024-T3

摘要

Corrosion protection of structural aluminium alloys for aerospace and marine applications is ofparamount importance. This is commonly achieved through the use of corrosion inhibitingcompounds. Constraints such as potential health issues associated with exposure to conventionalchromate-based corrosion inhibitors have led to the development of low toxicity corrosion inhibitorsfor a wide range of industries. Although numerous studies have been carried out on evaluatinginhibitor performance and associated mechanisms, limited studies have been done onunderstanding the film-forming characteristics of inhibitors and their role in providing corrosionprotection.Aluminium alloy, AA2024-T3 is an alloy, widely used in aerospace applications, with copper as itsprimary alloying element. Previous studies have discovered that due to the high affinity of coppertowards sulphur, inhibitors with a sulphur-based ligand bond with the Cu-rich intermetallic particles[1,2]. This study will focus on two inhibitors with distinctive molecular structures that are known fortheir high corrosion inhibition efficiency for the protection of aluminium alloy, AA2024-T3. Keyaspects of the film-forming behavior of these selected inhibitors and the test methods used toevaluate the inhibitor-induced films in a 0.1 M chloride solution are to be presented. Film formationwas investigated and discussed by means of various electrochemical corrosion monitoringmethods such as linear polarisation resistance (LPR), potentiodyanmic scanning (PDS),electrochemical impedance spectroscopy (EIS) and potential hold (PH). In conjunction with thesetechniques, surface analysis techniques, atomic force microscopy (AFM), scanning electronmicroscopy (SEM) and x-ray photoelectron spectroscopy (XPS) were utilized to achieve a deeperunderstanding of the inhibitor-induced film forming mechanism in relation to how the inhibitorstructure could influence corrosion protection via film formation. In addition, as an importantinhibitor parameter, the persistence of the inhibitor-induced film will also be discussed.