Enhancement of seawater corrosion resistance in copper using acetone-derived graphene coating

Abstract

We show that acetone-derived graphene coating can effectively enhance the corrosion efficiency of copper (Cu) in a seawater environment (0.5-0.6 M (∼3.0-3.5%) sodium chloride). By applying a drop of acetone (∼20 μl cm(-2)) on Cu surfaces, rapid thermal annealing allows the facile and rapid synthesis of graphene films on Cu surfaces with a monolayer coverage of almost close to ∼100%. Under optimal growth conditions, acetone-derived graphene is found to have a relatively high crystallinity, comparable to common graphene grown by chemical vapor deposition. The resulting graphene-coated Cu surface exhibits 37.5 times higher corrosion resistance as compared to that of mechanically polished Cu. Further, investigation on the role of graphene coating on Cu surfaces suggests that the outstanding corrosion inhibition efficiency (IE) of 97.4% is obtained by protecting the underlying Cu against the penetration of both dissolved oxygen and chlorine ions, thanks to the closely spaced atomic structure of the graphene sheets. The increase of graphene coating thickness results in the enhancement of the overall corrosion IE up to ∼99%, which can be attributed to the effective blocking of the ionic diffusion process via grain boundaries. Overall, our results suggest that the acetone-derived graphene film can effectively serve as a corrosion-inhibiting coating in the seawater level and that it may have a promising role to play for potential offshore coating.

Atomically Thin Hexagonal Boron Nitride Nanofilm for Cu Protection: The Importance of Film Perfection

“…< 0.1 Hz) corresponds to the charge transfer in the defective domains of the surface layer (either through the native oxide film or the BNNF coating). This result is comparable to that for graphene coated Cu [3,4] , which means that hexagonal networks in BNNF can effectively block the ion diffusion. The higher impedance in the BNNF-coated melted Cu substrate in comparison to the solid Cu substrate is attributed to the high quality of the BNNF.…”

“…[3][4][5][6][7] Good short-term anticorrosion performance was observed, [3][4][5] but over time, accelerated Cu oxidation and corrosion in air were found in the presence of graphene compared to the bare Cu substrate. [8,9] This acceleration is likely due to the high con-ductivity that assists electron transfer in the two-component galvanic cell between Cu and graphene, facilitating oxygen reduction and Cu oxidation around the defects in the long run.…”

“…Such a configuration is more stable when compared to OH * adsorption on the pure Cu(111) (Figure 2a Mixed results have been reported as to the efficacy of graphene as an ultrathin anti-corrosion layer. [3,4,8,9,49] It has been reported that the high electrical conductivity of graphene accelerates the Cu oxidation around the defects in the long run [8,9] , while it was recently suggested that the strong bonding between graphene and substrates such as Ni and Co prevents the migration of active reactants and consequently prevents oxidation of the metal substrates, even with defects in the graphene. [49] We have demonstrated above that oxidation of Cu underneath the BNNF is accelerated, especially along the BNNF edges, i.e., grain boundaries and defects.…”

“…Numerous pits are found on the bare Cu ( Figure S8b), indicating the penetration of Cl¯ ions into the substrates. [53,54] Cu (I and II) oxide [4] deposits were found mostly along the rolling lines (formed during manufacturing) on the bare ( Figure S8b) and BNNF-coated solid Cu substrates ( Figure S8f). The morphology of the BNNF on the melted Cu appears mostly unaltered after the EIS tests ( Figure S8g, h).…”

Graphene-based anticorrosive coatings for copper

“…In addition, these coatings are believed to alter the attractive electrical and thermal properties of copper. 8 Therefore, there exists a necessity to develop coating systems that are not harmful to the environment and at the same time do not interfere with the characteristic properties of the material.…”