The Effect of Corrosion on Conventional and Nanomaterial Copper Cold Spray Surfaces for Antimicrobial Applications

Abstract

Cold spray has been identified as having Cu coatings with greater antimicrobial properties than that of other additive manufacturing techniques. The addition of nanoagglomerate Cu powder to the cold spray process to form nanomaterial coatings has shown an increase in antimicrobial efficiency, as compared to conventional Cu, in the contact killing of Influenza A Virus. Corrosion testing, microstructural analysis, and composition measurement can help explain why cold sprayed nanomaterial Cu coatings performed better than conventional Cu coatings. Corrosion tests including electrochemical impedance (EIS), Linear Polarization (LP), and an Ion Release Assay all show nanomaterial Cu to have a greater corrosion rate than that of conventional Cu. Micrographs support corrosion results showing nanomaterial Cu to have much smaller grains than conventional Cu, indicating a greater percentage of grain boundaries available for Cu ion release into the environment. Composition testing through X-Ray Diffraction and X-Ray Photoelectron Spectroscopy (XPS) confirm sample surfaces to be comprised of pure Cu and Cu oxide, with the main oxide species present as Cu(i) or Cu 2 0. More research is needed to determine how the dominant Cu species develops based on environmental factors and how the presence of different species affect material antimicrobial properties.