Effects of Al2O3 on the microstructures and corrosion behavior of low-pressure cold gas sprayed Al 2024-Al2O3 composite coatings on AA 2024-T3 substrate

Pure Al 2024 coating and Al 2024-Al2O3 composite coatings were deposited on AA 2024-T3 alloy substrates using low-pressure cold gas spray (LPCGS). The content of Al2O3 in the feedstock was 20 wt%, 40 wt% and 60 wt %, respectively. The porosity, surface roughness, adhesion and surface residual stress of the coatings were analyzed. Electrochemical tests were carried out in neutral 3.5 wt% NaCl solution to evaluate the effects of Al2O3 on the corrosion behavior of the coatings. The results showed that the Al 2024-20 wt% Al2O3 composite coating possessed the lowest porosity (0.55%), relatively higher adhesion strength (50.68 MPa) and surface residual compressive stress (48.3 MPa) among the cold sprayed coatings. The results of corrosion tests revealed that the cold sprayed coatings provided sacrificial anode protection for the AA 2024-T3 substrate and that Al 2024-20 wt% Al2O3 composite coating exhibited the best corrosion resistance.