Graphene nanosheets are impermeable to chemical molecules and electrical conductivity. Thus, they are attractive candidates to enhance an epoxy zinc rich coating with a significant anticorrosion ...performance. Several studies focus on investigating the role of graphene in reinforcing the corrosion resistance of the coatings. However, there is a paucity of study that analyzing the anticorrosion relationship between the feature of graphene and epoxy zinc rich coating. The present study reported on epoxy zinc rich coatings with enhanced anticorrosion performance via embedding reduced graphene oxide/graphene oxide (rGO/GO) nanosheets. Thus, rGO and GO were prepared from natural graphite powder via the modified Hummers method. The results of Raman, XPS, FT-IR, SPM, and TEM analyses revealed the quintessential structure and morphology of rGO and GO. In addition, results from electrochemical measurements and the scanning vibrating electrode technique indicated that rGO effectively enhanced the cathodic protection duration of epoxy zinc rich coatings. rGO nanosheets exhibited dual functions that were identified in two aspects. First, the impermeable barrier role was exerted by including prepared rGO nanosheets into the polymer matrix. Second, superior electrical conductivity was utilized since the rGO nanosheets improved the efficiency of the electrical connection between the zinc particles and steel substrate.
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•Well-designed rGO nanosheets were used for enhancing anticorrosion.•rGO can enhance the cathodic protection duration of epoxy zinc rich coating.•rGO endowed composite coating exhibited optimal anticorrosion capability.•SVET confirmed the cathodic protection property of the coating.
To make good use of the barrier effect of graphene nanosheets and to reduce the uneven dispersion of zinc particles caused by its sedimentation, coating with alternate structure containing rGO was ...developed to provide Cu a long-term corrosion protection. Ionic liquid was used to obtain a better dispersion of rGO in solvent, which was proved by TEM, SPM images and sedimentation experiment. The enhanced long-term anti-corrosion protection of alternate coating was revealed by electrochemical tests. OCP and EIS results showed enhanced barrier performance of epoxy-G compared with epoxy and improved sacrificial anode protection of epoxy-Zn-G compared with epoxy-Zn. Tidal range-corrosion simulation test was also performed to show that the alternate coating can stick on copper substrate without peeling off even in harsh corrosive environment for 432 h. Furthermore, EIS, XRD, and XPS spectra together proved that the excellent anti-corrosion property of alternate coating was originated from the combination of sacrificial anode protection provided by zinc-rich-epoxy layer with barrier protection provided by rGO-doping-epoxy layer. This combination makes it reality to protect copper substrate from corrosion for longer time immersion in 3.5 wt% NaCl solution compared with epoxy-Zn-G.
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•An alternate epoxy-reduced graphene oxide/epoxy-Zinc multilayer coating is designed for enhancing anticorrosion.•The alternate structure can achieve an analogous sustained release effect of zinc particles.•The coating with alternate structure achieves longer protection than single structure in 3.5 wt% NaCl solution.•The coating with alternate structure shows strong adhesion strength in acidic environment for 432 h.
Although fluorinated graphene (FG) inherits the physical barrier characteristic from graphene, its limited dispersibility seriously impedes its application in corrosion resistance. Here, this study ...aims to present a facile strategy to effectively eliminate this undesired feature of FG. We developed a well-dispersed cerium oxide grafting fluorinated reduced graphene oxide (FrGO@CeO2) nanofiller to enhance the anti-corrosion properties of epoxy coating on Q235 mild steel surfaces. The in situ F-doping and hydrothermal techniques were employed to synthesize FrGO@CeO2 nanofillers and functionalize them with waterborne epoxy coating. Combining the electrochemical results and the corrosion morphologies, the resultant nanofillers were found to significantly reinforce the protection properties of epoxy coatings due to the physical barrier effect derived from FrGO. In addition to impermeability, FrGO presented the insulating nature and endowed composite coatings to combat galvanic corrosion. Local electrochemical impedance spectroscopy (LEIS) indicated that cerium oxide adsorbed on mild steel surface could form a passive layer and thus further resisted the metal corrosion process. The related corrosion protection mechanism of FrGO@CeO2/EP coating was proposed in detail, which could provide broader platforms for designing new corrosion protection materials.
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Fluorographene, a new alternative to graphene, it not only inherits the 2-dimensional (2D) layered structure and outstanding mechanical properties, but also possesses controllable C–F bonds. It is ...meaningful to reveal the evolution processes of the tribological behaviors from graphene to fluorographene. In this work, fluorinated reduced graphene oxide nanosheets (F–rGO) with different degree of fluorination were prepared using direct gas-fluorination and they were added into gas to liquid-8 (GTL-8) base oil as lubricant additive to improve the tribological performance. According to the results, the coefficient of friction (COF) reduced by 21%, notably, the wear rate reduced by 87% with the addition of highly fluorinated reduced graphene oxide (HF–rGO) compared with rGO. It was confirmed that more covalent C–F bonds which improved the chemical stability of HF–rGO resisted the detachment of fluorine so the HF–rGO nanosheets showed less damage, as demonstrated via X-ray photoelectron spectroscopy (XPS), Raman spectra, and transmission electron microscopy (TEM). Meanwhile, the ionic liquid (IL) adsorbed on HF–rGO successfully improved the dispersibility of F–rGO in GTL-8 base oil. The investigation of tribofilm by TEM and focused ion beam (FIB) illustrated that IL displayed a synergy to participate in the tribochemical reaction and increased the thickness of tribofilm during the friction process.
Although graphene film has received considerable scientific and industrial interest, the high electrical conductivity strongly limits its corrosion protection over a long-term scale. Here we develop ...an effective strategy to achieve the long-term corrosion protection performance of graphene film by fluorinated treatment. The success of fluorination strategy is evident in electrochemical impedance spectroscopy, local impedance module, and corresponding corrosion morphologies and structures. Even after 14 days’ immersion in 3.5 wt% NaCl solution, the low frequency impedance modulus of fluorinated graphene film with fluorinated treatment at 100 °C is an order of magnitude higher as compared with pristine one. The corrosion resistance over a large scale also persists in air environment. We propose that the fluorine atoms bond with carbon element on the edge of vacancy defects, inhibiting the corrosion-related molecules passing through the film via intrinsic defects, this is supported by the density functional theory calculations (DFT). In brief, through effective preparation, analysis of corrosion resistant performance, and theoretical calculation, the fluorinated graphene film with long-term anti-corrosion capability is highly expected to open a new platform for practical applications.
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•A novel Ti3C2Tx@CNF was synthesized via hydrogen bonding.•Ti3C2Tx@CNF strongly improved adhesion strength of waterborne epoxy coating under alternating pressure environment.•Ti3C2Tx@CNF endowed ...coating with active anticorrosion property in alternating pressure.•Corrosion protection mechanism of coating was systematic clarified.
Cellulose nanofiber was grafted on Ti3C2Tx (Ti3C2Tx@CNF) and then Ti3C2Tx@CNF nanohybrid acted as nanofiller to endow epoxy coating superior barrier property. Electrochemical tests and corrosion products revealed that incorporation of Ti3C2Tx@CNF into epoxy could significantly improve its anti-corrosion performance. Even immersion in marine alternating hydrostatic pressure (AHP) environment for 240 h, the impedance modulus of composite coating was one order of magnitude higher as compared with controlled samples. Besides, cross-sectional structure confirmed that Ti3C2Tx@CNF remarkable improve the compactness of coating and thus conferring active adhesion strength with twice higher than that of pure epoxy after 240 h immersion in AHP.
Graphene has long been considered a superlative protection material due to its extraordinary characteristics and properties. However, its high electrical conductivity can facilitate the ...electrochemical corrosion of metal, which strongly limits its anti-corrosion applications. Here, we developed a facile fluorination strategy to suppress the corrosion promotion activity of graphene. Fluorinated reduced graphene oxide (FrGO) exhibited low electrical conductivity (3.643 × 10−13 S/cm), which proved unable to trigger micro-galvanic corrosion. Furthermore, acridizinium ionic liquid (IL) MAcBr was noncovalently grafted on FrGO to achieve the well dispersion in the polymer matrix. Results revealed that FrGO-IL nanohybrid can be stably dispersed in the epoxy resin. Electrochemical impedance spectroscopy revealed that incorporating a small percentage of FrGO-IL into waterborne epoxy matrix effectively improved the corrosion resistance performance of the coating by exerting the superior shielding effect and inhibiting the ability for micro-galvanic corrosion. Moreover, local electrochemical and scratching tests further confirmed that FrGO-IL significantly reinforced the corrosion protection capability of waterborne epoxy coating because the well-dispersed nanohybrid enhanced the integrity of the composite coating, effectively utilizing the labyrinth effect. Our finding could inspire the development of new graphene-based materials with superior protection properties for metal materials.
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In this work, a polyethyleneimine-grafted graphene oxide (PEI-GO) hybrid material was prepared as an effective filler to improve the anticorrosion performance of waterborne epoxy coating. The ...successful covalent reaction between PEI and GO was confirmed by FTIR, Raman, XPS, XRD and TGA measurement. The epoxy coating filled with modified and unmodified graphene oxide was characterized by SEM and Raman spectroscopy. The results showed that PEI-GO was uniformly dispersed in the epoxy matrix. It was found that the PEI-GO hybrid materials displayed considerable superiorities in improving corrosion resistance of epoxy coating by EIS and SVET. Besides, the optimal content (0.25 wt%) of PEI-GO was obtained through experimental results. Moreover, the desirable anticorrosive property of PEI-GO/EP composite coating is proposed to be mainly attributed to the role of PEI, which fully stimulated the barrier properties of graphene oxide by improving its dispersion in the epoxy coating and also enhanced the crosslink density of epoxy resin by increasing the surface activity of the graphene oxide to the epoxy groups.
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•Polyethylenimine (PEI) was grafted on graphene oxide (GO) surface.•The PEI-GO hybrid improved the compatibility between GO and epoxy resin (EP).•The PEI-GO/EP composite coating had longer service life and better anti-corrosion property.•The presence of PEI-GO hybrid increased the density of epoxy coating and suppressed the corrosion of metal substrate.
2D nanomaterials, with extraordinary physical and chemical characteristics, have long been regarded as promising nanofillers in organic coatings for marine corrosion protection. The past decade has ...witnessed the high-speed progress of 2D nanomaterial-reinforced organic composite coatings, and plenty of breakthroughs have been achieved as yet. This review covers an in-depth and all-around outline of the up-to-date advances in 2D nanomaterial-modified organic coatings employed for the marine corrosion protection realm. Starting from a brief introduction to 2D nanomaterials, the preparation strategies and properties are illustrated. Subsequently, diverse protection models based on composite coatings for marine corrosion protection are also introduced, including physical barrier, self-healing, as well as cathodic protection, respectively. Furthermore, computational simulations and critical factors on the corrosion protection properties of composite coatings are clarified in detail. Finally, the remaining challenges and prospects for marine corrosion protection based on 2D nanomaterials reinforced organic coatings are highlighted.
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•A waterborne epoxy composite coating integrating barrier/inhibition property was achieved.•h-BN nanosheets took a positive barrier effect on coatings’ corrosive protection.•SZP ...molecules effectively inhibited the corrosive process.•The synergistic effects provided by h-BN nanosheets and SZP molecules were confirmed by EIS and LEIS methods.
Herein, we employed the impermeability of hexagonal boron nitride (h-BN) nanosheets and the inhibition property of strontium zinc phosphate (SZP) corrosion inhibitor to prepare h-BN/SZP waterborne epoxy composite coatings and explored their corrosion protection performance while immersed in 3.5 wt% NaCl solution. On the basis of lip-lip interaction between hexagonal boron nitride, the h-BN nanosheets were exfoliated to a few layers and functionalized with 3-aminopropyltriethoxysilane (APTES). The anti-corrosion performance of the as-prepared waterborne epoxy composite coatings applied on mild steels was evaluated using potential and impedance measurements, fitted pore (pinhole) resistance and salt spray. The corrosion products and the localized electrochemical impedance spectroscopy (LEIS) analysis of the synthesized (Fh-BN, SZP)/EP coating suggested that the superior corrosion resistance of the coated mild steel was attributed to a synergetic effect between physical barrier role of h-BN and inhibition of SZP. Our strategy provides a new protection method in coatings for metallic substrates and will ameliorate the basic research and industrial applications of h-BN nanosheets.
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