Bond Coat Assisted Enhancement in Microstructural, Mechanical and Corrosion Behavior of AZ91 Magnesium Alloy Cold Spray Coated with Aluminum Alloys

Cold spray coating technique was used to deposit coatings of AA6061 aluminum alloy on AZ91 magnesium alloy substrates. A bond coat of commercially pure aluminum was used to facilitate deposition of the AA6061 powders. Two cold spray coating iterations were conducted to optimize the coating's microstructural features such as porosity, surface roughness, and interface microstructure. Mechanical properties such as hardness, wear resistance, and adhesion behavior were characterized and used as metrics to compare the coatings with the substrate. The corrosion behavior of the coated and uncoated samples was characterized using multiscale and multimodal corrosion measurements comprising macroscopic potentiodynamic polarization and scanning electrochemical cell microscopy. The coated substrates exhibited a significant improvement in mechanical and corrosion performance as compared to the uncoated substrate.