Cold-Sprayed AA2024/YSZ Composite Coatings on AZ31B Magnesium Alloy: Microstructure, Adhesion, and Corrosion Behavior

Cold-sprayed metal matrix composite (MMC) coatings have been developed as a promising technique to enhance the surface characteristics of lightweight alloysbased on magnesium. In the present work, composite deposit based on AA2024/YSZ with different weight percentages (5, 10, and 15 wt.%) was deposited on AZ31B Mg alloy through low-pressure cold spray (LPCS) process. The effect of reinforcement weight percentage on the microstructure, adhesion strength, microhardness, and corrosion resistance was systematically investigated. Themicrostructure showed a dense and uniform morphology with improved bonding for the 10 wt.% YSZ-containing coating (C10R). The microhardness values were seen to increase from 67 HV for the substrate to 164, 189, and 210 for the 5, 10 and 15 wt.% YSZ-containing coatings, respectively. The adhesion strength was seen to have a maximum value of 59.82 MPa for the 10 wt.% YSZ-containingcoating. The electrochemical tests revealed a significant improvement in corrosion protection for all coated samples. Among the coatings, the C10R coating exhibited the highest corrosion protection efficiency of 32.08%, which can be attributed to its optimum coating compactness, strong interparticle bonding, and superior interfacial integrity. Corrosion morphology and phase analysis showed the presence of stable aluminum-based oxide/hydroxidefilms, which contributed to enhanced corrosion protection. As a result, C10R coating shows the best performance in terms of both corrosion resistance andmechanical properties. The developed coating demonstrates significant potential for improving the corrosion resistance of Mg alloys under the investigated electrochemical conditions. Nevertheless, additional long-termimmersion testing is required to evaluate its durability under prolonged service exposure.