A novel, structurally coloured coating for aluminium alloys

Abstract

Abstract Current approaches to coat aluminium surfaces that use paints and organic coatings to protect them from corrosion and provide an aesthetic finish, are also energy intensive and involve high emissions of VOCs. The use of these coatings is becoming increasingly restricted by global efforts towards more environmentally sustainable surface finishing technologies. A recent development based on porous anodised aluminium (PAA) and metal nanowire deposits is presented here, which may become a competitive alternative to paint and organic coatings. Anodising and electrodeposition do not emit VOCs and are less energy intensive. By controlling the conditions for anodising and metal electrodeposition, coatings in a wide spectrum of colours can be produced, including greys, black, blues, purples, and greens. Characterisation of the coating morphologies and corresponding colours agrees with simulated results based on the Fresnel equations and Bruggeman Mixed Media Approximations.