Optimization of the Microstructure and Performance of Aluminum Alloy Cold Spray Coatings on Magnesium Alloy Substrates

The widespread implementation of Magnesium alloys for the automotive industry warrants an improvement in their corrosion performance and their ability to withstand dissimilar material contact under corrosive environments. Solid-phase coating methods offer opportunities to precisely tune the coating microstructure, thickness, and coating-substrate interface. We report on the optimization and characterization of cold spray deposited AA6061 aluminum alloy coatings on Magnesium alloy corrosion and automotive components. Coatings with low porosity, high thickness, hardness, and excellent corrosion properties were achieved using a bond coating composed of pre-treated CP-Al powders. The dynamic nature of the cold spray process enabled the formation of a metallurgical bond at the coating-substrate interface leading to high adhesion strengths. Furthermore, the ability of cold spray coatings to repair manufacturing defects was explored, and the microstructural mechanism for the same was investigated.