Corrosion resistance of electrodeposited Ni–Al composite coatings on the aluminum substrate: Fid-Bau Portal

Corrosion resistance of electrodeposited Ni–Al composite coatings on the aluminum substrate

Ghanbari, S. / Mahboubi, F.

Research highlights ► Nickel coating with Al particles was successfully deposited on aluminum alloy (7072) via sediment co-deposition. ► Maximum Al particles content in coating was 22wt.%. ► Zincate coating had a distinct effect on adhesion of nickel coating. ► Al metal particles shifted polarization curves to negative potentials and corrosion rate is decreased. ► Deposition of Al particles could be explained by the Guglielmi’s model for inert particles.

Abstract Ni matrix–Al particle composite coating was adopted via sediment co-deposition (SCD) method on the zincate coated aluminum substrate. Surface morphology was investigated by scanning electron microscopy (SEM). The electrochemical behavior of the coatings was studied by polarization potentiodynamic test in 3.5wt.% sodium chloride using a three electrode open cell. The effect of the electroplating parameters on the Al co-deposition was studied. Maximum of 22wt.% Al particles were deposited in the coating. It was found that the zincate coating plays an important role in improving the nickel layer adherent. Furthermore, incorporation of aluminum particles in Ni matrix refined the Ni crystal coatings. However, polarization curves shifted to negative potentials and corrosion rate is decreased.