Graphene-Infused Zinc-Rich Epoxy Coating for Corrosion Protection Enhancement in Oil and Gas Steel Structures

Abstract

Abstract This study aims to investigate the impact of incorporating graphene into zinc-rich epoxies, with the primary objective of extending the cathodic protection of steel plates against corrosion and reducing the zinc content in the paint formulation. To achieve this, graphene-modified zinc-rich epoxy coatings (G-ZRE) were developed, containing varying concentrations of 0.05 wt% and 0.2 wt% graphene in a matrix of 65 wt% zinc-rich epoxy. Electrochemical impedance spectroscopy (EIS) was employed to assess the effect of graphene on the corrosion protection capabilities of the G-ZREs. Additionally, Open Circuit Potential (OCP) measurements were utilized to gain deeper insights into the fundamental mechanism underlying the protective characteristics of the composite coating. Salt spray tests were conducted for 3000 hours, and the creep age was calculated to validate and corroborate the findings derived from the EIS and OCP measurements. The results demonstrated that the addition of 0.05 wt% graphene in the 65 wt% zinc-rich epoxy coatings increased the duration of cathodic protection from 558 hours to 850 hours. The analysis from EIS and OCP indicated that the primary protective mechanism for G-ZREs involved a combination of barrier and sacrificial modes of protection. In contrast, the control coating without graphene exhibited solely sacrificial protection, resulting in accelerated failure compared to the G-ZREs. Furthermore, the salt spray tests revealed that the creepage area of the 0.05 wt% G-ZREs was the smallest, further confirming the excellent barrier protection offered by the composite coating. Therefore, these findings could help reduce the reliance on zinc particles as pigments in zinc-rich coatings, thereby mitigating the environmental impact associated with the potential leaching of zinc particles into the surrounding environment. Overall, incorporating graphene into zinc-rich epoxy coatings in the petroleum industry offers enhanced corrosion resistance, extending the lifespan of equipment and infrastructure. This reduces maintenance costs, improves operational efficiency, and contributes to the advancement of knowledge while benefiting the petroleum industry.