Biological fouling and corrosion resistance of Ni-based coating on AH32

Abstract

ABSTRACT To reduce the destruction of organic biological fouling in marine steel, nickel-based (NiCrAlY) transition coatings with and without silver (Ag) doping were prepared on AH32 marine steel by plasma spraying. The coatings exhibited a layered structure, and AlNi3 (111), (200), and (220) diffraction peaks were detected. The Ag (111) peaks were also observed for the Ag-doped coatings. The number of sulphate-reducing bacteria (SRB) adsorbed on the coating surfaces reduced after immersion in the bacterial solution, and their shells were disintegrated because of the presence of Ag. The corrosion potentials of AH32, NiCrAlY, and NiCrAlY(Ag) coated AH32 plates were nearly identical at approximately −720 mV. After being covered with organic paint, the corrosion potential and current density of the NiCrAlY(Ag) coating increased to −624 mV and decreased by one order of 2.75 × 10− 6 A cm−2, respectively. The NiCrAlY(Ag) coating effectively inhibited biological fouling.