Protection of AA2024 alloy against wear and corrosion by HVAF sprayed AlCuFe coating

Quasicrystalline (QC) AlCuFe coating is produced on the AA2024 alloy using high-velocity air-fuel (HVAF) spraying. The HVAF sprayed coatings are studied in as-deposited and subsequently annealed (400°C, 1 h) states. XRD, SEM, and EDX analysis revealed a two-phase microstructure comprising QC icosahedral ψ-phase (the volume fraction of ∼75%) and interlayered bcc β-phase that remains the same as that in a water-atomized AlCuFe powder used as feeding material. The used annealing exerts a negligible effect on the protective properties of the HVAF coating that possesses good adhesion strength (>12 MPa), a high HV microhardness (7.1 ± 0.2 GPa), nanohardness (11.1 ± 0.2 GPa), elastic modulus (169 GPa), the essentially lowered wear losses (0.71 μm), coefficient of friction (CoF≈0.03), and corrosion current density (6.7 μm cm−2) in a 3.5%NaCl medium. These characteristics are much better than those of the original AA2024 alloy.