Anticorrosion Performance Of Epoxy Coatings Research Articles

ZnO-functionalized arabinogalactan and xylan nanocomposite epoxy coating for the corrosion protection of AISI 5140 steel

The anticorrosion performance of epoxy coatings can be enhanced by using biopolymer nanocomposites. The permeability of the corrosive ions through defects and pores can be prevented by the functionalization of biopolymers and their introduction into the epoxy matrix. Herein, ZnO-functionalized arabinogalactan and xylan (AG-ZnO and XL-ZnO) nanocomposites were fabricated using ultrasonication and characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). The surface morphology of the prepared biopolymer nanocomposite was analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (HR-TEM). The corrosion performance of the epoxy coating containing AG-ZnO and XL-ZnO on AISI 5140 steel was evaluated via electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies (PDP) in 3.5 wt% NaCl. The results indicated superior corrosion protection, with inhibition efficiencies of 89.71 % and 93.27 % for the AG-ZnO and XL-ZnO incorporated epoxy coatings, respectively. Furthermore, 0.3 wt% of the prepared biopolymer nanocomposite in the epoxy coatings provided superior protection due to the increased dispersion and even distribution of zinc oxide. After the introduction of the XL-ZnO and AG-ZnO biopolymer nanocomposites, there was a threefold and twofold increase in the charge transfer resistance, respectively, compared to that of the pure epoxy coating. Compared to those of the pure epoxy (icorr = 1.23 ×10-6 A cm−2), the icorr values of the XL-ZnO-EP (icorr = 0.16 ×10-6 A cm−2) and AG-ZnO-EP (icorr = 0.65 ×10-6 A cm−2) coatings significantly decrease. The prepared coatings were subjected to water contact angle measurements and the 3D topographical morphology was determined using atomic force microscopy (AFM). A reduced roughness was observed for the prepared coatings.

Doped STR@mSiO2-GO nanocomposite coatings for enhanced anticorrosion protection of copper

This study presents an innovative approach to improve the anticorrosion performance of epoxy coatings by incorporating 2-hydroxy-5-((4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl) benzaldehyde (STR) molecules into a matrix of mesoporous silica (mSiO2) grafted onto graphene oxide (GO) sheets. The resulting porous hybrid composites (STR@mSiO2-GO) underwent thorough characterization via scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Corrosion resistance was assessed using salt spray testing and electrochemical impedance spectroscopy (EIS). The results show the superior corrosion resistance of the polymer nanocomposite coatings compared to pure epoxy coatings. Notably, incorporating 10 wt% TiO2 into the mSiO2-GO epoxy matrix significantly increased the corrosion protection efficacy from 74.48 % to 99.85 %. This enhancement is attributed to synergies between TiO2 nanoparticles and the mSiO2-GO matrix, leading to a hydrophobic polymeric nanocomposite coating that significantly boosts corrosion resistance. This study introduces an innovative approach for developing high-performance epoxy coatings with improved anti-corrosion properties, showcasing promising strides in corrosion protection technology.

Modification of Electrochemical Exfoliation of Graphene Oxide with Dopamine and Tannic to Enhance Anticorrosion Performance of Epoxy Coatings

Graphene oxide (EGO) was prepared via an electrochemical exfoliation method and modified with dopamine and tannic acid, and it was then incorporated into epoxy resins to enhance their barrier, self-healing and anticorrosion performances. The morphologies, structures and compositions of the HGO (GO prepared via Hummers’ method), EGO and MGO (modified EGO) were characterized via SEM, TEM, AFM, Raman spectroscopy and XPS. The protective performances of the epoxy varnish coatings, EGO/epoxy coatings and MGO/epoxy coatings with different contents of MGO were evaluated via EIS measurements, and the role played by MGO on the coating defects was determined via LEIS and salt spray tests on the scratched coatings in a 3.5% NaCl solution. The results show that the dopamine and tannic were successfully grafted onto the EGO surface via π–π interactions and chemical bonding, and that the dispersibility of the MGO in the epoxy resins was facilitated. The epoxy coatings with a 0.1% addition of MGO possessed the best anticorrosion properties (|Z|0.01Hz > 1010 Ω cm2 after 70 days immersion in 3.5% NaCl solution) in comparison to the other coatings due to the “labyrinth effect” formed by the uniformly dispersed MGO. Meanwhile, the grafted tannic acid was released at the coating defects and provided inhibition functionalities for the substrate. As a result, the corrosion of the carbon steel was significantly decreased. This work provides a new perspective on the efficient modification of electrochemically exfoliated GO epoxy coatings for metals by combining the advantages of dopamine and corrosion inhibitors.

Anisotropic dispersion promoting and passivation protecting of CA@JNs@Zn2+ Janus nanosheets on epoxy anticorrosive coatings

Defects in the curing process of epoxy coatings tend to deteriorate the anticorrosion performance of the coatings. An important way to enhance the anticorrosion performance of epoxy coatings is to add flaky fillers. In this paper, anisotropic Janus nanosheets (JNs) were prepared and modified by cardanol (CA) and Zn2+. Then, the obtained CA@JNs@Zn2+ Janus composite nanosheets were introduced into epoxy coatings. When the content of CA@JNs@Zn2+ is 0.2 %, the mechanical properties and corrosion resistance of the coating were effectively improved. The tensile strength of 0.2 %-CA@JNs@Zn2+/EP coating is 79 % higher than that of pure epoxy coating. The EIS analysis showed that the low-frequency impedance of the coating remained as high as 16.45 Gohm·cm2 after 35 days of immersion, and remained above 10 Gohm·cm2 during the whole immersion period, which demonstrating the optimal corrosion resistance. This paper provides a theoretical basis for the preliminary application of Janus material in the field of anticorrosion, and the prepared composite coatings are expected to be used for anticorrosion in harsh environment.

Intelligent self-healing anti-corrosive coatings with crosslinked conducting polypyrrole hydrogel network

The cross-linked conducting polypyrrole hydrogel (CPH) network is designed for preparing the corrosion-resistant and self-healing epoxy coatings, which are used for the long-term active corrosion control of Mg alloys substrate in 3.5 wt% NaCl solution. The encapsulated phytic acid (PA) inhibitors are uniformly distributed in the crosslinked CPH network with an encapsulation amount of 16.77%. The inductively coupled plasma–optical emission spectrometry test indicates that the releasing rate of the PA inhibitors from the crosslinked CPH network rises with the increased pH values, reflecting their pH-responsive feature. Afterward, the epoxy coatings impregnated with various contents of the CPH network are coated on the Mg alloy surface, and their corrosion resistance and self-healing performances are evaluated using electrochemical and immersion tests. Results indicate that the epoxy coatings with 5 wt% CPH displays the most durable corrosion-resistant and self-healing performances with the highest coating resistance (4.39 × 105 Ω cm2) and charge-transfer resistance (8.28 × 105 Ω cm2) values even after 28 days of immersion. The encapsulated PA inhibitors continuously release to the cracked region in response to the local pH variations and react with Mg2+ ions generated from the active corrosion site. Consequently, an Mg-PA protective layer is formed to suppress further corrosion activities. Both the enhanced inherent barrier effect of epoxy coatings, the pH-responsive release behaviors of the PA inhibitors from crosslinked CPH network and the durable anodic protection effect of CPH are beneficial for improving the anti-corrosive performance of the epoxy coatings. It is believed that this kind of crosslinked CPH network will provide a new strategy for designing highly self-healing and anti-corrosive performance of epoxy coatings for the active corrosion control of other metals.

ZIF-8 and benzimidazole co-modified h-BN for enhancing anti-corrosion performance of epoxy coatings

Two-dimensional hexagonal boron nitride (h-BN) has excellent corrosion resistance and barrier ability, showing unique advantages in the field of anti-corrosion. The h-BN was assembled with Zeolite imidazolate framework material (ZIF-8) and benzimidazole (BI), and an active filler (h-BN/ZIF-8@BI) with shielding and active corrosion resistance was prepared. Zeolite imidazolate framework material was in-situ grown on h-BN surface and loaded with benzimidazole (BI), prepared an active anticorrosive filler with high shielding property (h-BN/ZIF-8@BI). The microstructure, crystal form, element composition, corrosion inhibition ability and thermal stability of h-BN/ZIF-8@BI were studied. The barrier, corrosion inhibition and anti-friction properties of EP/h-BN/ZIF-8@BI combined with F51 epoxy resin were explored. EIS test shows that the corrosion inhibition efficiency of h-BN/ZIF-8@BI is as high as 81.8 %. The impedance modulus of the steel matrix protected by the composite coating was about 2 orders of magnitude higher than that of the control sample, showing excellent barrier ability. In addition, the salt spray test proves that the composite coating has excellent corrosion inhibition characteristics. Taber testing machine shows that the wear mass loss of EP/h-BN/ZIF-8@BI coating is 34.5 % lower than that of EP coating. This work provides a novel idea for the preparation of high barrier, active anticorrosive and wear resistant anticorrosive coatings, and provides a new horizon of the composite coatings.

Investigation of synthesized planar Cu-MOF and spherical Ni-MOF nanofillers for improving the anti-corrosion performance of epoxy coatings

Recently, polymer coatings containing metal-organic frameworks (MOFs) have offered promising potential as anti-corrosion coatings. In this regard, the current study investigated two types of synthesized MOFs composed of Cu and Ni ions coordinated with 2-methylimidazole, as novel nanofillers with high anti-corrosion behavior. Molecular structures of synthesized MOFs were optimized by Gaussian software. FTIR, Raman spectroscopy, XRD, and EDX analysis of nanoparticles indicated that metal ions have successfully reacted and coordinated with the organic ligands. FE-SEM and TEM images of nanoparticles showed planar and spherical structures for Cu-MOF and Ni-MOF, respectively. The BET test illustrated the porous structure of synthesized nanoparticles with a high surface area and 35 nm average pore diameters. Moreover, UV–Vis analysis revealed Cu-MOF and Ni-MOF pH-responsive behavior. These nanostructured materials were incorporated into an epoxy (EP) matrix to be applied to mild steel substrates. Electrochemical impedance spectroscopy (EIS) and salt spray examination demonstrated active corrosion inhibition and self-healing behavior of nanocomposite coatings. The salt spray test indicated improved performance with fewer corrosion products and reduced blistering and delamination. Coatings without an artificial scratch that contained 0.15 wt% MOF nanoparticles exhibited long-term anti-corrosion performance, even after being immersed in saline solution for nine weeks; in terms of |Z|0.01Hz, Ni-MOF/EP and Cu-MOF/EP (109 Ω·cm2) outperformed neat EP (105 Ω·cm2).

Surface-modified cerium oxide as a corrosion inhibitor to enhance the performance of epoxy coatings

PurposeThe study aims to investigate the anticorrosion performance of epoxy coatings using modified cerium oxide (CeO2) by terephthalic acid (CeO2-t) and fumaric acid (CeO2-f) as corrosion inhibitors.Design/methodology/approachThe chemical state of CeO2-t, and CeO2-f were analyzed by infrared radiation (IR) and X-ray diffraction (XRD). The effect of different inhibitors on the coating properties was analyzed by neutral salt spray tests (NSST) and electrochemical impedance spectroscopy (EIS).FindingsThe results of IR and XRD illustrate that the modification of CeO2 was successful, and fumaric acid underwent a ring-opening reaction with epoxy resin (EP) in the coatings. The results of NSST and EIS showed that the coatings containing CeO2-f exhibited the best anticorrosion performance.Originality/valueCeO2 is an effective inhibitor of the organic coatings. When surface modified, it is chemically bonded to EP, enhancing the anticorrosion performance of EP.

Synthesis and characterisation of sulfated-nanocrystalline cellulose in epoxy coatings for corrosion protection of mild steel from sodium chloride solution

Biomaterials such as nanocrystalline cellulose (NCC) have attracted considerable attention in coating production industries due to their sustainable and renewable attributes. This work presents NCC obtained from the hydrolysis of microcrystalline cellulose and sulfation treatment of NCC to obtain sulfated-NCC (S-NCC) using a chemical agent for corrosion protection of mild steel in 3.5 wt.% NaCl solution. Two types of anticorrosion coatings were formulated by incorporating either NCC or S-NCC of different loading ratios (10 wt.% to 50 wt.%) to epoxy-matrix to form composite coatings. The structural characterisations of NCC and S-NCC showed that the sulfation introduced sulfate ester groups on NCC. The morphological characterisations displayed that the average particle sizes obtained for both ranged between 40 nm and 50 nm. Electrochemical measurements were conducted to obtain the anticorrosion behaviour of the composite coatings in the corrosive solution. The results indicated that the sulfation of NCC improved the anticorrosion performance to 99.7%, and the best performance was obtained from a coating containing 20 wt.% S-NCC. Finally, a mechanism for corrosion protection of S-NCC coating was proposed where electrostatic repulsion of chloride species from the coated mild steel occurred. This study, therefore, demonstrates the applicability and importance of S-NCC in improving the anticorrosion performance of epoxy coatings for maritime applications.

Preparation of modified montmorillonite/graphene oxide composites to enhance the anticorrosive performance of epoxy coatings

Preparation of modified montmorillonite/graphene oxide composites to enhance the anticorrosive performance of epoxy coatings

Synergistic Effect between Zinc Particles and Graphene on the Anti-Corrosion Performance of Epoxy Coatings

Synergistic Effect between Zinc Particles and Graphene on the Anti-Corrosion Performance of Epoxy Coatings

Azadirachta indica (Neem) self-healing efficacy assessment in epoxy primer coatings: A bio-responsive strategy for counteracting corrosion

The active anticorrosion performance of epoxy coatings containing encapsulated crude vegetal extracts of Azadirachta indica (Neem) leaves to protect aluminium alloy 6061 in seawater was investigated. Ethanol and hexane were the loading solvents. The molecules-metal interaction alongside the formation of an anticorrosive film of the defective coatings was evaluated using electrochemical techniques while adjusting the pH of the seawater. The unloaded scratched epoxy coating was the comparison. In the alkaline chloride solution, the hybrid coatings exhibited better anticorrosion via extrinsic self-healing. XPS validated the composition and chemical species of the bionanocomposites.

Influence of acidic and alkaline environmental anticorrosive performance of epoxy coatings based on polyaniline/carbon nanotube hybrids modified with ionic liquid

Polyaniline (PAni) and their hybrids with carbon nanotube (PAni@CNT) were prepared through inverse emulsion polymerization of aniline in the presence of different amounts of the ionic liquid (IL), 1-butyl-3-methyl-imidazolium tetrafluorborate (bmim.BF4). Transmission electron microscopy (TEM) was used to evaluate the morphology of the particles and cyclic voltammetry was employed to evaluate the electroactivity of these compounds in different pH media. The presence of IL promoted a great improvement of the redox activity of PAni@CNT in acidic medium and PAni in acidic and neutral media. Epoxy-based coatings containing 1 % of PAni and PAni@CNT were applied on carbon steel substrate to investigate their corrosion resistance using electrochemical impedance spectroscopy (EIS) technique. The coatings, deliberately scratched, were immersed in acidic and alkaline media. PAni@CNT hybrid presented better anti-corrosion response than PAni in acidic, neutral and alkaline environments and the presence of IL resulted in additional improvement of this property in all media. These results provide new possibilities for the preparation of environmentally friendly coating to be effective in a wide range of pH media. The morphology and band gap energy of the ER-based films were also investigated by optical micrograph and ultraviolet-visible spectroscopy, respectively. Narrower band gap energy was observed for the films containing hybrid materials mainly those containing IL in the hybrid, probably due to the improvement of charge transfer between particles promoted by the IL.

Preparation and Characterization of Graphene Oxide/Polyaniline/Polydopamine Nanocomposites towards Long-Term Anticorrosive Performance of Epoxy Coatings.

To address the challenging issues of metal materials corrosion in industries, which has caused huge economic losses and security threats to many facilities in marine environments, functional polymer coatings have been widely used and regarded as one of the simplest and most effective methods to prevent such an undesirable event. In this study, a new type of coating filler consisting of graphene oxide/polyaniline/polydopamine (GO-PANI-PDA) nanocomposites has been successfully synthesized. The morphology, structure, composition, and corrosion resistance performance of the GO-PANI-PDA (GPP) nanocomposites were investigated via a series of characterization methods. The results from our electrochemical impedance spectroscopy, potentiodynamic polarization curve and salt spray experiment showed that the best corrosion resistance performance of the coating is from GPP 21 with the epoxy/GO-PANI:PDA ratio of 2:1, which exhibited a positive corrosion potential (−0.51 V) shift from epoxy/GO-PANI coating (−0.64 V). The corrosion current density (3.83 × 10−8 A/cm2) of GPP 21 is nearly an order of magnitude lower than that of epoxy/GO-PANI (7.05 × 10−7 A/cm2). The good anti-corrosion performance was fascinatingly observed in salt spray tests even without obvious corrosion phenomenon after 30 days of testing. Due to these remarkable properties, GPP nanocomposites can be an outstanding candidate for the rapid development of broadband shielding and anticorrosive materials.

Difunctional Silicon Dioxide Combined with Graphene Oxide Nanocomposite to Enhance the Anticorrosion Performance of Epoxy Coatings.

The nanocomposite BTA-SiO2-GO was fabricated for the purpose of metal corrosion protection. Herein, the BTA-loaded mesoporous silica nanocontainers were prepared through a facile one-step synthetic method. Subsequently, graphene oxide (GO) was combined with the resultant BTA-SiO2 compound because GO had a superior barrier property and impermeability. We must note that the double functional groups exist on SiO2. Benzotriazole (BTA), as an inhibitor, can be loaded into the nanocontainer and GO can also be modified by it, resulting in excellent dispersion in epoxy coatings, which were conducive to enhancing its anticorrosion performance. In this way, the nanocomposite endows the coating system with both self-healing and physical barrier abilities. The EIS results indicated that the impedance value of the BTA-SiO2-GO composite coatings was up to 1.2 × 109 Ω cm2, which indicated excellent corrosion resistant properties.

Anti-corrosion performance and mechanical properties of epoxy coatings containing microcapsules filled with linseed oil and modified ceria nanoparticles

In this study, the anti-corrosion and mechanical properties of epoxy coatings containing microcapsules filled with linseed oil and neat and modified ceria nanoparticles were evaluated. To this end, first, the surface of ceria nanoparticles was modified with Cerium (III) nitrate hexahydrate using different methods and then the corrosion resistance of linseed oil containing 1 wt% of nanoparticles was studied by electrochemical impedance spectroscopy (EIS). To evaluate the protection mechanism of cerium nanoparticles, the corrosion performance of linseed oil containing calcium carbonate and Zirconia nanoparticles was also studied. In the next step, urea-formaldehyde microcapsule containing linseed oil and 1 wt% nano-ceria modified from the previous step, was synthesized via in situ polymerization in an oil-in-water emulsion. The results of EIS Test showed that the addition of ceria nanoparticles to the microcapsule’s core content improves the anti-corrosion performance of the epoxy coatings containing microcapsules due to increased barrier properties as well as through inhibition mechanism. The mechanical properties of the coating samples decreased up to 35% by the addition of microcapsules due to disruption of the structural integrity of the resin matrix. However, the DMTA test revealed that the glass transition temperature of the samples did not change significantly by adding microcapsules to the coating samples.

Micron-scale ultrathin two-dimension zirconia nanosheets towards enhancing anticorrosion performance of epoxy coatings

Micron-scale ultrathin two-dimension zirconia nanosheets towards enhancing anticorrosion performance of epoxy coatings

Effect of accelerated ageing procedures and flash rust inhibitors on the anti-corrosive performance of epoxy coatings: EIS and dynamic-mechanical analysis

The present study reports the combination of electrochemical impedance spectroscopy (EIS) technique with dynamic-mechanical (DMA) properties and pull-out strength to monitor the anticorrosive properties of high solid epoxy coatings on pre-treated carbon-steel surfaces with flash rust inhibitors. For this purpose, five different surface treatments and two epoxy system coatings were employed. The coatings were submitted to corrosion performance testing such as salt-spray, immersion in seawater and cyclic protocol in attempt to simulate marine conditions. The pull-out testing revealed mainly cohesive failure of both epoxy coating systems even after the accelerated ageing process. EIS analysis indicated an increase of the resistive characteristic of the coating after ageing treatment, which was explained by an increase of the crosslink density, as indicated by DMA analysis. The EIS results also suggested slight interfacial effect of flash rust inhibitors since they presented a major coating resistance than hydroblasted panels. Therefore, unlike the expected degradation after artificial ageing, the two high solids epoxy coating systems kept and even presented increased barrier property after ageing. Furthermore, no negative influence of wet surface preparation with or without inhibitors was observed in this study.

The Effect of the Modification of Mica by High-Temperature Mechanochemistry on the Anticorrosion Performance of Epoxy Coatings.

Epoxy resin was directly grafted onto the surface of mica powder by high-temperature mechanical ball milling. This method was used to achieve a chemical reaction between the epoxy resin and mica that cannot be carried out under conventional circumstances. The results show that an epoxy resin layer with a thickness of approximately 10 nm formed on the surface of the mica. This modified mica filler exhibited a significant change in its hydrophilic properties. The dispersion of mica and its compatibility with organic coatings also significantly improved. In addition, the modified mica filler was added to the epoxy coating. The improvement of the coating’s compactness and toughness is the reason for its anti-corrosion performance enhancement.

Preparation of aniline trimer modified graphene oxide new composite coating and study on anticorrosion performance

Graphene oxide (GO) has attracted much attention in anticorrosive coating applications due to its excellent mechanical properties, thermochemical stability and large specific surface area. In this paper, aniline trimer modified GO composites (ATGO) were prepared through modifying GO at different temperatures of 65 °C, 80 °C, 95 °C, and 110 °C, respectively. Aniline trimer modified GO composite coatings (ATGO/EP) were then prepared by adding different quantities of ATGO to epoxy coating, with the mass fractions of 0.05%, 0.1% and 0.3%, respectively. The resulting composite coatings were then sprayed onto Q235 steel plates for characterization and anticorrosion testing. A series of characterization methods such as x-ray diffraction (XRD), Raman spectra, Fourier transform infrared spectroscopy (FT-IR), Atomic force microscopy (AFM) and Transmission electron microscopy (TEM) were used to prove that aniline trimer was successfully grafted on GO. The optimal reaction temperature for ATGO preparation was determined to be 95 °C. Using anticorrosive tests such as Electrochemical impedance spectroscopy (EIS), salt spray test and adhesion test, it was proven that the addition of ATGO can significantly promote anticorrosion performance of epoxy resin (E-44). The optimal addition amount of ATGO to prepare composite coatings was determined to be 0.05 wt%. Its coating resistance after soaking in 3.5% NaCl solution for 10 days was 6.87 × 106 Ω, which was two orders of magnitude higher than the 3.89 × 104 Ω of pure epoxy coating. The importance and originality of this study is that it explores an effective way to improve the anticorrosion performance of epoxy coatings.