Raman Singh

Abstract:

Corrosion of engineering alloys and its mitigation measures cost any developed economy ~4% of their GDP (i.e., ~$8b annually to Australia and ~$250b to USA). Traditional measures such as development of corrosion-resistant alloys and conventional coatings have not always provided durable corrosion resistance, particularly in highly demanding situations. Thus, a novel and disruptive approach is immensely commercially attractive. This presentation will discuss graphene coating as a disruptive approach to durable corrosion resistance [1-2], chronological evolution of the field, and success in circumventing the related challenges. The presenter's group demonstrated that just 1-2 atomic layers of graphene coating can improve corrosion resistance of copper (Cu) by two orders of magnitude in an aggressive chloride solution (similar to seawater) [2]. However, the improvement in corrosion resistance of Cu due to graphene coating vary remarkably in different studies, i.e., from >2 orders of magnitude [2], to only 10 times [3] to little improvement [4]. In fact, a few subsequent studies [5,6] have categorically demonstrated graphene coated Cu to show remarkably inferior long-term oxidation resistance to bare Cu. The presenter's recent investigations [7,8] have provided mechanistic understanding of such variabilities. The group also had considerable success in circumventing the factors/challenges that contributed to the development of deleterious defects in graphene film that trigger accelerated corrosion (instead of protection) as reported in other studies [5,6]. The graphene developed the most recent studies [7,8] have been demonstrated to provided durable corrosion resistance to nickel [7] (see Figure 1) and copper [8]. However, developing graphene on most common engineering alloys (e.g., mild steel) by CVD poses a few fundamental scientific challenges that this presentation will discuss.