Feasibility of Anodic Coatings on Al2O3 Fiber-Reinforced Aluminum Metal Matrix Composites for Wear and Corrosion Resistance

Aluminum and its alloys exposed to air are protected by a native oxide film that is heterogeneous in nature and does not provide adequate corrosion resistance. For this reason, anodized coatings are often used for corrosion as well as wear protection on aluminum alloys, While there is a wealth of information available about the effectiveness of anodized coatings on aluminum and aluminum alloys, little can be found about the coatings effectiveness on aluminum matrix composites. Metal matrix composites, in general, offer new challenges in corrosion protection. Depending on the fiber material, galvanic reactions can occur at the fibermatrix interface that could accelerate the corrosion process. Fiber pull-out can also affect the surface by leaving behind crevices that can also lead to preferential corrosion sites. The object of this study was to investigate the effectiveness of a type III anodic hardcoat on a 3M NEXTEL Al2O3 fiber-reinforced aluminum matrix composite. The corrosion and wear properties are presented and compared with an anodized monolithic baseline.