Method for Repairing Damaged Ion Vapor Deposition (IVD) Aluminum Coatings

This Phase I effort will try to develop a method for repairing damaged IVD aluminum coatings instead of the brush cadmium plating currently used by Navy. Due to the toxic nature of cadmium, the new method with non-hazardous operation procedures mainly consists of cold spraying and shotpeening (CSS) by using aluminum as the coating material, which includes the steps of: (1) damaged area cleaning by sandblasting; (2) coating preparation by cold spraying specially processed aluminum powders; (3) shotpeening the coated area to densify the coating; (4) thickness correction and chromate conversion coating if necessary. The new coating will meet or exceed the performance of the coating it repairs, and has a good bonding strength with the substrate and adjacent material, and also provide an adhesive base for subsequent organic coatings. In order to realize this method, an apparatus will be designed and fabricated during this Phase I project. The apparatus is a compact and integration system, containing three functions: sandblasting cleaning, cold spraying and coating densification. It is also lightweight and easy to transport to any place where the repair is needed. The whole repair process will be done in a few minutes, depending on the size of the damaged area.