Graphene: An Effective Anti-Corrosion Material

Corrosion has long been one of the most severe challenges confronting industries including iron and steel, metallurgy, construction, transportation and many others. Statistics show that the annual direct economic loss caused by corrosion worldwide reaches approximately 2.5 trillion US dollars, accounting for 3.4% of the global GDP in 2013. Another set of data indicates that every one and a half rotations of the second hand on a watch corresponds to one ton of steel being corroded into residues across the globe. Compared with devastating natural disasters such as hurricanes and earthquakes, corrosion is more destructive and triggers heavier economic losses. Nevertheless, given its silent occurrence and widespread distribution worldwide, it has not yet attracted sufficient attention.

Adoption of effective anti-corrosion measures can cut such losses by 15% to 35%, equivalent to 375 billion to 875 billion US dollars. Zinc-based and chromium-based coatings serve as the mainstream industrial anti-corrosion solutions. However, chromium is toxic and poses adverse risks to human health and the ecological environment. In addition, these coatings come with high costs, while their anti-corrosion efficiency and service life fail to fully meet practical requirements. Therefore, there is an urgent demand for anti-corrosion coatings featuring higher efficiency, environmental friendliness and lower costs.

Graphene, a two-dimensional planar material with a hexagonal honeycomb lattice constructed by carbon atoms bonded via sp² hybridization, has drawn extensive attention from the scientific community, industrial enterprises and governments worldwide in recent years. Benefiting from the intrinsic properties of chemical bonds between carbon atoms, graphene exhibits exceptional toughness and excellent ductility; it can undergo large-angle bending without fracture. Its Young’s modulus is around 1100 GPa with a tensile strength of 130 GPa, roughly 100 times higher than that of high-grade steel. Moreover, graphene is optically transparent to visible light yet impermeable to gases, delivering outstanding barrier performance along with superior chemical stability. These unique properties make graphene a highly promising candidate material for metal anti-corrosion coatings.