Microstructure and Corrosion Behavior of Cold-Sprayed Aluminum Alloy/Inconel Composite Coatings

Abstract

Inconel 718 is a high-strength metal alloy that exhibits excellent corrosion resistance. Cold spraying is a deposition technique that does not induce phase changes and so was used to form an anti-corrosion composite coating that was composed of an Al5056 matrix reinforced with In718. These composite coatings exhibited a higher corrosion potential and lower corrosion current than the pure Al5056 coating, which provided effective cathodic protection to Al substrate if the substrate corrosion was inadvertently initiated. The electrochemical impedance spectroscopy results indicated that it was the addition of In718 that improved the corrosion resistance of the cold-sprayed coatings. The In718 induced a compacting effect, which reduced the porosity of the coating, and this was found to be the primary reason for the increased corrosion resistance of the Al5056/In718 composite coatings compared to the Al5056 coating.