An electrochemical investigation of corrosion on AA2024-T3

An electrochemical corrosion study on the high strength aluminum alloy 2024-T3 has been conducted. This Cu-rich aluminum alloy contains several metallic phases, which are embedded in the Al bulk and provide mechanical strength. These phases afford for the use of 2024-T3 in aerospace applications giving the alloy a high strength to weight ratio. The phases are commonly referred to as inclusions or intermetallic particles (IPs). These IPs have been well documented to function as cathodes and promote corrosion through either Al oxidation or basic attack on the Al bulk matrix from dioxygen reduction products. The scope of this dissertation has been to observe the cathodic capabilities of the IPs by observing the electrochemical phenomena associated with them. This has been done through the use of scanning probe microscopy including scanning electrochemical microscopy (SECM) and diffusion limited electrochemical techniques such as the rotating disk electrode (RDE) and the wall-jet electrochemical flow cell. Scanning electron microscopy (SEM) was routinely used to observe structural damage that the alloy incurred throughout the experiments. Several corrosion inhibitors have also been examined with the above methods. Government regulations are imposing the quest for new corrosion inhibition treatments to replace the existing toxic heavy metal treatments currently used. In this context, new corrosion protection coatings based on inherently conductive polymers (ICPs) along with the "benchmark" Cr(VI) treatments were studied to observe their corrosion inhibition mechanisms.