An investigation on the corrosion behaviour of B₄C-reinforced AA5083 aluminium alloy in sodium chloride solution using electrochemical impedance spectroscopy

In this research, the role of B₄C-reinforcing particles on the corrosion behaviour of Al5083/B₄C nanocomposite has been investigated. Al/B₄C nanocomposite powder with weight percentages of 3 and 7 of reinforcing phase was prepared by mechanical milling method. The resulting powder was initially hot-pressed and then hot-extruded. The microstructure of the sample was studied using scanning electron microscopy and their corrosion behaviour was studied using potentiodynamic polarization and scanning electrochemical impedance spectroscopy methods in different immersion time intervals. The results showed a uniform distribution of reinforcing particles and also the scattering of intermetallic particles at the surface of the samples. However, increasing the content of B₄C particles in the composite samples enhances the cathodic and anodic reactions by increasing the content of intermetallic particles as cathodic sites on the surface, so that higher corrosion current density is observed in the composite samples with 7 wt% B₄C. Finally, it was concluded that increasing the value of B₄C decreases the corrosion resistance of the B₄C-reinforced composite samples in sodium chloride solution, which makes it unsuitable in marine applications.