Formation of nickel aluminide coatings via post heat treatment of nickel plated AA2024 aluminum alloy

In this research, nickel was electrodeposited on AA2024 aluminum using direct current. The coated specimens were then heat-treated at different temperatures of 450, 500, and 550°C for 30, 60, 90 and 120 minutes under argon shielding gas. The treated specimens were characterized by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction analysis (XRD). The presence of Al3Ni2 and Al3Ni intermetallic compounds were noticed at 450°C after 120 minutes and 500 and 550°C after 60 minutes. Microstructural studies also demonstrated that heat treatment at 550°C for 90 and 120 minutes leads to cracks at the coating/substrate interface. The maximum hardness reached 1000 Vickers after heat treating at 500°C for 120 minutes.