Preparation and Performance of Nano Anti-fouling Coatings by Microarc Oxidation

Nano anti-fouling ceramic coatings were formed at the surface of marine Ti-6Al-3Nb-2Zr alloys by a single-step micro-arc oxidation(MAO).Surface morphology,microstructure,oxide layer thickness,element valence,chemical composition were characterized by means of SEM,TEM,optical microscope,X-ray photoelectron spectroscopy,EDX.Bonding strength,insulating performance,the tribological properties and anti-fouling properties of the coatings were also investigated in this article.Results indicated that the oxide film reaches about 20μm thickness.Transmission electron microscopy(TEM) showed that the films were composed of noncrystal and 20-50nm nanocrystal TiO₂ including Cu₂O.The bonding strength between the Ti-6Al-3Nb-2Zr substrate and the film was about 50MPa.The ceramic coating exhibited good insulation,abrasion and anti-fouling character.A small amount of marine organisms were clinged on the surface of nano anti-fouling coating after hanging six month in shallow seawater,but naked titanium alloys were completely attached.