Corrosion resistance and antibacterial activity of a surface coating created by super-spread wetting of liquid copper on laser-ablated carbon steel

Abstract

In this work, a Cu coating on carbon steel with a fine crevice structure created by laser modification was produced without the use of contaminants by exploiting the super-spread wetting properties of liquid metal. The chemical composition, microstructure, bonding properties, corrosion resistance, and antibacterial activity of the Cu coating were investigated. The coating consisted of metallic Cu containing a minor fraction of Cu2O, with surface flakes and a dense inner layer with 0.1 % porosity and thickness of 337 ± 10 μm. Three-point bending tests showed the Cu coating had good adhesion with the carbon steel substrate. Corrosion tests demonstrated that the dense structure of the Cu coating blocked electrolyte contact with the carbon steel substrate for at least 336 h, indicating that the coating provides a barrier against galvanic corrosion. Assays of antibacterial activity and biofilm inhibition suggested that growth of Escherichia coli and Staphylococcus epidermidis on the Cu coating was 99.9 % lower than that on the substrate after 2 h surface contact, and biofilm formation on the coating was >90 % lower than that on the substrate. The combined anti-corrosive properties and antibacterial activity demonstrate the potential for the Cu coating to prevent transmission of bacterial infections in hospitals and public environments.