Alkaline Corrosion-Resistant Sealant for Anodized Aluminum Alloys

Corrosion resistance of anodized aluminum sealed with conventional and a new sealant was tested against the alkaline, acid and neutral chloride salt solutions. The results show that the conventional water based sealants have good acid and Neutral Salt Fog resistance; however, they do not possess the necessary alkaline corrosion resistance to be used for decorative and automotive exterior applications. A new anodic coating sealant was developed to provide the necessary alkaline corrosion resistance along with the acid and neutral salt attack resistance. Acid Dissolution Test (ADT) Rating, Alkaline Corrosion Resistance, Neutral Salt Fog, Heat Resistance and Alkaline Car Wash Detergent tests were done in accordance with General Motors Spec GMW 14665. Results revealed that this novel sealant is significantly capable of meeting the rigorous GMW 14665 specification and can be used for sealing the anodic coatings used in automotive exterior applications.