Investigation of quaternary Al-based quasicrystal thin films for corrosion protection

Recent work has shown that thin film quasicrystal coatings have unique properties such as very high electrical and thermal resistivities and very low surface energy. Aluminum-based quasicrystals are insulator alloys composed of approximately 70% of aluminum. The corrosion related properties of aluminum-based quasicrystal thin film coatings have been studied on quasicrystal-coated AA-2024 substrates. The thin film deposition parameters are discussed. Results of microstructural and surface chemistry analyses of the quasicrystal films are presented. The corrosion protection properties of the films have been studied by potentiodynamic scan and electrochemical impedance spectroscopy. Analysis of the electrochemical data indicates that nanostructured quasicrystal films significantly resist corrosion of AA2024-T3 substrates in constant immersion environment. Morphology studies and electrochemical analysis of quasicrystal films have shown that quaternary Al-based quasicrystal thin films possess unique corrosion control properties. Superior resistance to electrolyte attack makes these coatings strong candidates for corrosion-resistant surface treatment of Al alloys. These films can be utilized as conversion coatings for Al substrates or incorporated into a full coating system containing an organic primer and a topcoat. (C) 2003 Elsevier B.V. All rights reserved.