Optimization of Anodic Oxidation of Aluminum for Enhanced Adhesion and Corrosion Properties of Sol-Gel Coatings

The anodizing process for clad and bare AA2024-T3 has been optimized as a surface preparation technique prior to sol-gel coating deposition. The combination of anodized aluminum surfaces and organically functionalized sol-gel chemistry have been investigated to impart elevated corrosion resistance and increased mechanical properties to the aluminum metal. A duplex anodizing process has been developed to utilize the natural corrosion resistance properties of sulfuric acid anodizing with the adhesion and hosting properties of phosphoric acid anodizing. The novel anodizing process and sol-gel sealed surfaces have been characterized using field emission scanning electron microscopy, energy dispersive X-ray spectroscopy. Performance of the sol-gel treated anodic layers is evaluated by neutral salt spray testing, electrochemical impedance spectroscopy and rain erosion testing. (C) 2016 The Electrochemical Society. All rights reserved.