Corrosion mechanism of graphene coating with different defect levels

This paper reports the corrosion mechanism of graphene coated Cu with different defect levels. Here, we show the corrosion process and the galvanic corrosion on graphene coated Cu. The corrosion mechanism of graphene coated Cu was studied by Raman, SEM, TEM, and SEVT technologies. The high density of defects on multi-layered graphene promoted the diffusion process of the corrosive medium, once the corrosive medium permeated into the interface of graphene and Cu, the corrosion on Cu initiated. The galvanic corrosion accelerated the corrosion of Cu anode was revealed by the scanning vibrating electrode technique. The expanding of corrosion products on Cu induced the exfoliation of graphene. The imperfect of graphene induced the corrosion and the galvanic cell accelerated the corrosion on Cu substrate which both resulted in the failure protection of graphene coating and the exfoliation of graphene from copper substrate.