Effect of graphene coatings on the morphology of submillimeter thin copper wires after salt spray aging

Unprotected copper conductors are prone to oxidation and corrosion, especially when in contact with salt water or at high temperature. In this study, we compared commercially available coating with graphene oxide and plasma-enhanced chemical vapor deposition (PECVD) graphene coated wires in terms of antioxidation and anticorrosion protection. Samples were subjected to aging tests in a salt spray chamber. Thereafter, both the degree of coverage and surface protection were assessed by X-ray photoelectron spectroscopy measurements and scanning electron microscope images, which showed significant surface protection for both graphene coatings. Raman spectra obtained from the transferred coatings revealed their structural stability, which shows that it is possible to successfully use few atomic-layers-thick coatings to protect commercially available wires. Wire resistance tests performed at temperatures up to 320°C showed similar or better results for graphene coatings than for commercially coated wires. Additionally, images of the wires after high temperature tests showed high antioxidation protection for graphene coatings, especially for PECVD. The results of this study can be applied for further research on mechanical suitability of the coatings and wires themselves, especially after high-temperature CVD processes. Such studies may lead to novel Cu wire processing technologies. Graphical abstract