Graphene layers on metals: A disruptive approach to durable corrosion resistance

Corrosion, an age-old phenomenon, costs dearly; hence, possible technological means for corrosion mitigation/amelioration have almost been exhausted. Therefore, finding a disruptive mitigation approach is non-trivial, but any such discovery (e.g., graphene coatings) has immense social, commercial and technological implications. Graphene is attractive for numerous industrial applications. Among its several remarkable properties, graphene also possesses exceptional chemical resistance, outstanding impermeability to such chemicals that cause corrosion, and extraordinary toughness, which constitute the unique combination of characteristics for an ideal coating material for corrosion resistance. The review provides an in-depth critique of corrosion resistance of metals due to graphene coatings developed by chemical vapor deposition (CVD), identifies and critically assesses the associated challenges, and their demonstrated circumventions. CVD graphene has been widely developed on copper, nickel and their alloys; however, developing CVD graphene on common alloys, such as mild steel, is a non-trivial challenge. This review comprehensively discusses the compelling reasons of the challenge and evolution of an innovative prior surface modification of steel and its optimization, enabling successful CVD graphene coating on steel that conferred remarkable and exceptionally durable corrosion resistance. The prior surface modification is generic in nature and can be employed for CVD graphene on other engineering alloys.