Optimization strategies for graphene-based protection coatings: a review

Graphene has become an emerging and promising option in the field of protection coating for anti-corrosion due to its specific properties in chemical inertia and physical impermeability. It can be applied to metal protection coating in forms of either atomically thin films or composite materials, known, respectively, as pure chemical vapour deposition (CVD) graphene coatings and graphene composite coatings (GCCs). Nonetheless, various structure defects, synthesis imperfections and graphene's positive potential to metals would make graphene-based protective coatings tend to exhibit corrosion promotion by arousing micro-galvanic corrosion, largely undermining its anti-corrosion efficiency. Based on this, many optimization strategies and methods have been conceived and applied to the graphene-based protection coatings in these two aspects for improving its anti-corrosion efficiency. For example, a good dispersion and orderly arrangement of graphene derivatives in the GCCs can largely optimize its anti-corrosion performance. Here, this paper separately reviews detailed optimization strategies, corresponding mechanisms and key factors for the use of representative graphene-based materials in these two aspects, with the aim of providing comprehensive knowledge and a roadmap of developing cheap, powerful and effective barrier technologies. Finally, perspectives on opportunities and challenges in improving the barrier coating efficiency of graphene-based materials are discussed.