Corrosion Resistance and Mechanism of Graphene Oxide Composite Coatings on Magnesium Alloy

Abstract

Triethanolamine (TEA)/graphene oxide (GO) composite coatings were prepared by electrodeposition on magnesium alloy AZ91. The morphology, structure, and corrosion behaviors of the composite coatings for Mg alloy in the 3.5 wt % NaCl solution were studied by scanning electron microscopy, X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, electrochemical tests, immersion experiments, and quantum chemical calculation. The results indicated that the TEA/GO composite coatings were distributed evenly on the Mg alloy substrate. The electrochemical tests showed that the composite coating had lower corrosion current density and higher film resistance. The corrosion process of the composite coatings for Mg alloy in the 3.5 wt % NaCl solution could be separated into three processes, and the physical models were set up. The quantum chemical calculation indicated that TEA and GO could be adsorbed on the Mg alloy surface to exhibit a good barrier between the substrate and corrosive medium to prevent the aggressive ions from the substrate surface.

Experimental and computational studies of graphene oxide covalently functionalized by octylamine: electrochemical stability, hydrogen evolution, and corrosion inhibition of the AZ13 Mg alloy in 3.5% NaCl

“…19 Also, the corrosion inhibition of the peruorinated polysiloxane-functionalized graphene oxide coated Mg alloy was studied by Pyo et al Their results showed excellent inhibition efficiency as compared with conventional epoxy-coated Mg alloys. 20 The corrosion inhibition of the silane-incorporated graphene oxide-coated Mg alloy was studied in 3.5% NaCl medium by Zhang et al 21 The corrosion inhibition studies of the polyvinyl alcohol functionalized graphene oxide coated with 2024 aluminum alloy in 0.2 M NaCl medium were performed by Lutkenhaus. 22 The results showed that with the increased percentage composition, the inhibition efficiency increased as well.…”

Corrosion Resistance and Forming Mechanism of the Lauric Acid/Graphene Composite Films on Aluminum Alloy by Electrodeposition

“…The corrosion resistance of the samples in corrosion electrolyte was examined by electrochemical impedance spectroscopy (EIS) measurement. [ 39 ] The Nyquist plots and fittings of the samples are shown in Figure . It is shown in Figure 6 that the aluminum alloy substrate impedance is the smallest in all samples.…”

“…To further explain the properties of the film, quantum chemical calculations were considered as an effective method. [ 39,42 ] LA and rGO were optimized for the structures to ensure that the energy of the molecular system was minimal. The energy of the highest occupied molecular orbital ( E HOMO ) and energy of the lowest unoccupied molecular orbital ( E LUMO ) of LA and rGO were obtained and are shown in Figure .…”

“…The stability of the molecular was inversely proportional to the energy gap. [ 39 ] In other words, the smaller the energy gap of the molecule, the easier it is for it to take part in a chemical reaction. It is shown from the results that Δ E (LA) < Δ E (rGO), which indicates that it is easy for LA to provide the electrons with the empty orbital of Al alloy to form the chemical bond.…”

One-Step Method for Preparing Dispersive Tea Polyphenol/Graphene Nanosheets Enhanced with Anticorrosion Performance

“…However, potential interlayer π-π interactions that are imposed on stacking between contiguous graphene nanosheets may result in low solubility of the solution [19]. Currently, functionalized graphene is modified via various chemical reactions and interactions, such as covalent and noncovalent modification [20], π-π stacking, and van der Waals or hydrogen bonding [21]. However, the surface functionalization of graphene by using organic agents suffers from limited expandability and environmental problems.…”