Anti-corrosion Mechanism Research Articles

Preparation of Anticorrosive Coating with No Solvent for Repairing

The solvent-free fast-curing coating for repairing is prepared using polyurea as matrix and graphite nanoplatelets (GNPs) as fillers. The effects of GNPs on the coating are studied. The coating is prepared by HDI tripolymer and polyetheramine. The GNPs is functionalized (f-GNPs) by aminopro-pyltriethoxysilane (APTES) in mixture of water and ethanol. The performances of the coatings are tested by salt spray time, polarization curves and electrochemical impedance. The coating presents solvent-free and fast-curing characteristics and is suitable for repairing. The f-GNPs provide both physical barrier and coulomb block for the coating. When the f-GNPs added amount is 0.6 wt%, the salt spray resistance time of the coating is more than 420 h, and the corrosion potential is –0.6428 V. The effects of GNPs on coating are investigated. The results can provide a new idea for preparation of anticorrosive coating used for repairing, and can benefit in-depth understanding of the influence of f-GNPs on the coatings. The coating for repairing is prepared by adding f-GNP as fillers. The anticorrosive mechanism and performance of the coating are discussed in detail.

Study on the synthesis of PANI/CNT nanocomposite and its anticorrosion mechanism in waterborne coatings

In this paper, PANI encapsulated CNT (PANI/CNT) composite with nanofibers morphology has been successfully prepared through the oxidative polymerization of aniline in stable CNT suspension. The thickness of the PANI shell and the interface interaction can be adjusted by the mass ratio of aniline to CNT based on the formation of the weak electron donor-acceptor interactions between CNTs and aniline salts in the in-situ oxidative polymerization system. The synthesized PANI/CNT nanocomposite has the reversible redox activity not only in acidic but also in neutral medium. The PANI/CNT organic composite coating can be prepared by filling PANI/CNT nanocomposite into the water-based acrylic/amino baking paint. The results of polarization curve, electrochemical impedance and salt spray resistance indicate that the composition and morphology of PANI/CNT nanocomposite have a significant effect on the intelligent metal protection function when deliberate damage occurs and the long-term corrosion resistance of the composite coating. The PANI/CNT (8:1) nanocoating exhibits the most excellent intelligent protection activity, while the PANI/CNT (2:1) nanocoating demonstrates the excellent long-term anticorrosion performance. The nanofibrous PANI/CNT nanocomposite benefits to form a conductive network in the organic coating, which determines the cathodic inhibition and the anodic passivation protection of PANI/CNT metal anticorrosion mechanism. This research provides a new idea for the preparation of environmentally friendly active anticorrosive materials.

Corrosion behavior and mechanism of GH3535 alloy in NaOH, HF and H2O2 solution

Corrosion behaviors of GH3535 immersed in NaOH, HF and H2O2 solutions were investigated at RT for 600 h. The micro-morphology of surface and cross section was systematically characterized by SEM, EDS, EPMA, XRD and Nano Indenter. GH3535 showed excellent corrosion resistance in NaOH solution, but suffered serious pitting corrosion and slight grain boundary corrosion in HF solution, whereas only distinct hole corrosion in H2O2 solution due to the depletion of carbides. Element depletion, fall-off of carbides, decrease of hardness and Young’s modulus of GH3535 were detected in HF and H2O2 solution. However, NaOH solution is chemically inert towards GH3535. Corrosion mechanism was also explored based on the experimental measurement and thermodynamic calculation. Results not only provide the theoretical guidance for understanding the anticorrosion mechanism of GH3535 and purifying the molten salt, also expand the application of GH3535.

Investigating the effectiveness of Watermelon extract-zinc ions for steel alloy corrosion mitigation in sodium chloride solution

In the present study, the green-renewable Watermelon extract (WME):Zn inhibitive complexes were introduced in order to reduce the mild steel (MS) corrosion in a 3.5% sodium chloride (NaCl) solution. The chemistry of WME:Zn compounds were probed via the Fourier-transform infrared spectroscopy (FT-IR) and ultraviolet–visible (UV–Vis) spectroscopies and the results displayed successful interactions between the WME and Zn. The WME:Zn complex anti-corrosion impact and protection mechanism were discovered by EIS and Tafel analyses during 72 h exposure to the neutral chloride-type solution, respectively. The test results confirmed that the WME:Zn controlled 96% of MS corrosion in the saline solution with the help of mixed-type interactions. The immersed samples were examined by field-emission scanning electron microscope (FE-SEM) (equipped with energy dispersive spectroscopy (EDS)) and the structures of the deposited oxides were assessed by grazing incidence X-ray diffraction (GIXRD) techniques, that confirmed the WME:Zn protective layer generation over the MS substrate. The atomic force microscope (AFM) displayed the generation of the high smooth layer with lower heterogeneities and the contact angle (CA) results proved the semi-hydrophilic behavior of the inhibited samples.

Superhydrophobic and smart MgAl-LDH anti-corrosion coating on AZ31 Mg surface

Layered double hydroxides (LDHs) have been widely used as “smart” containers in the field of metal corrosion protection, and have broad industrial prospects. It is environmentally friendly and feasible to use aliphatic carboxylates and corresponding acids as substitutes for harmful corrosion inhibitors. However, previous studies rarely involved comparing the anti-corrosion mechanisms of different aliphatic acids modified on the LDH surface, and the durability of the prepared coatings also needs to be improved. In this work, MgAl-LDH laminates were grown in situ on AZ31 substrates by a hydrothermal method, and then modified by sodium laurate (SL) and sodium dodecylbenzene sulfonate (SDBS). Due to the physical barrier effect of the LDH layers, the spatial repulsion effect of the air film and the ion exchange reactions in the interlayer galleries, the functional coatings prepared exhibit smart and superior anti-corrosion performance on the magnesium substrates in 3.5 wt.% NaCl solution. Compared with LDH-SDBS-8 coating, the obtained superhydrophobic LDH-SL-8 coating shows more excellent long-term corrosion protection owing to the stronger intercalation capacity.

Adsorption of Gardenia jasminoides fruits extract on the interface of Cu/H2SO4 to inhibit Cu corrosion: Experimental and theoretical studies

An eco-friendly corrosion inhibitor is a target pursued by many corrosion researchers all the time. In this work, we studied the protective effect of Gardenia jasminoides fruits extract (GFE) for copper in 0.5 mol∙L─1 H2SO4 dependence upon multifarious tests and methods. It is obtained in electrochemical measurements that the maximum inhibition efficiency (η) of GFE exceeds 90% at different temperatures and η of 400 mg/L GFE is almost 93% at 298 K. The most appropriate model of GFE sorbing on Cu surface belongs to Langmuir adsorption. Both Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) demonstrates the bonding information. It is perceived that GFE is brilliantly capable of safeguarding Cu from eroding by the corrosion particles adopting scanning electron microscopy (SEM) method and atomic force microscopy (AFM). The anti-corrosion mechanism is further interpreted and comprehended utilizing quantum chemistry calculation and molecular dynamics simulation analysis.

Three piperazine compounds as corrosion inhibitors for copper in 0.5 M sulfuric acid medium

BackgroundSearching for and developing green corrosion-resisting drugs plays an significant role in protecting Cu during its pickling treatment. The toxicities and inhibitive performances are closely correlated with their molecular formulas. MethodsTherefore, Amoxapine, Loxapine and Clozapine, all of which belong to piperazines, were assessed as inhibitive agents to protect Cu from corrosion in 0.5 M H2SO4 via electrochemical measurements, surface morphologies and theoretical calculations. According to the electrochemical results, the anti-corrosion efficiencies of AP, LP and CP reached their maximums at 5 mM, namely 94.0༅, 95.2༅ and 96.6༅, respectively. They were all proved to be cathodic-type corrosion inhibitors. The morphology analysis implied the shaping of protective films on Cu surfaces. Moreover, the absorption of AP, LP and CP on Cu surfaces deferred to the Langmuir isotherm model, confirming the analysis of Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Theoretical calculations revealed their adsorption models and anti-corrosive mechanisms. Significant FindingsBoth experiment and calculation manifested favourable corrosion-proof properties of the three researched drugs. Further analysis also proved the enhanced inhibitive effect of methyl that connected with benzene ring owing to its conjugative effect. Furthermore, N atom possessed higher electronegativity and accordingly stronger electron-donating ability compared to O atom. The corrosion-resisting efficiency of Clozapine was 96.6%, being higher than that of Loxapine which was 95.2%.

Solvothermal synthesis of functionalized carbon dots from amino acid as an eco-friendly corrosion inhibitor for copper in sulfuric acid solution

In this work, novel N-doped carbon dots (N-CDs) were synthesized from citric acid and l-serine. The results of fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) show that there are many unsaturated bonds and polar groups in the N-CDs. The inhibition performance of the concerned zero-dimensional nanomaterial for copper was investigated by electrochemical, combining FT-IR, XPS and Raman to investigate the corrosion products. Results indicate that the N-CDs were found to be effective inhibitor with the suppression efficiency as high as 98.5% means after immersed for 24 h, and they interacted with copper substrate by chemical & physical adsorption. Moreover, the related anticorrosion mechanism was explored and elucidated in detail. The purpose of this work is to explore eco-friendly and efficient corrosion inhibitor materials for metal protection.

Corrosion inhibition of aluminum current collector with molybdate conversion coating in commercial LiPF6-esters electrolytes

A molybdate conversion coating (MCC) is developed to circumvent aluminum current collector (AlCC) corrosion in commercial LiPF6-esters electrolytes. The obtained MCC exhibits compact structure and good combination with AlCC matrix. Electrochemical tests show that MCC reduces the corrosion current density by an order of magnitude. Furthermore, in Li||NMC333 cells, the capacity retention of the cell with MCC-AlCC cathode is 75.6 % at 4.5 V high voltage, while that of control cell is only 7.2 %. The anticorrosion mechanism could be contributed to the stable artificial passivation layer which prevents HF erosion and the depth expansion of pitting corrosion.

Composition design and anticorrosion performance optimization of zinc molybdate pigments

Exploring the design of zinc molybdate pigments to optimize their properties is an interesting work. Three types of zinc molybdate, amorphous ZnMoO4, Zn5Mo2O11·5H2O, and β-ZnMoO4, were synthesized by regulating the synthesis conditions. Experimental results revealed that the monoclinic β-ZnMoO4 possessing a distorted octahedral [ZnO6]/[MoO6] cluster structure exhibited the optimal anticorrosion and photocatalytic properties. Then, the synergistic anticorrosion mechanisms of β-ZnMoO4 were proposed: multilayer shielding layer protection and photoelectrons suppression effect of anodic reaction. Next, three surfactants, sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and polyvinylpyrrolidone (PVP-K30), were employed to modulate the growth of β-ZnMoO4. Experimental data showed that the induced modulation of PVP-K30 could greatly increase the specific surface area and photoelectrons production efficiency of β-ZnMoO4. Besides, the charge transfer resistance of β-ZnMoO4-P (synthesized with PVP-K30) was 25.58 times higher than that of β-ZnMoO4-0 (synthesized without surfactant) after 72 h of immersion in 3.50 wt.% NaCl solution. Consequently, the design strategy of zinc molybdate pigments provides a reference for the improvement of performance of other inorganic anticorrosion pigments in industry.

Comparative investigation on thermal corrosion of alloy coatings in simulated waste incinerator environment

The thermal corrosion test and ash adhesion test were performed in this work to quantify the corrosion resistance of coatings prepared by plasma transferred arc welding (PTA), twin wire arc spray (TWAS) and high-velocity oxygen-fuel spray (HVOF) technologies. Results showed that TWAS coatings would fall off above 550 °C. PTA and HVOF coatings were excellent even at 650 °C. For HVOF-NiCr coatings, as Cr content increased from 7.22 % to 21.55 %, the corrosion resistance was enhanced linearly. This study revealed the anti-corrosion mechanism and provided a guidance for coating application in boilers.

Inhibition of carbon steel corrosion in HCl solution using N-oleyl-1,3-propanediamine based formulation

The relatively environmentally benign ingredient diethyl-aminoethanol (DEAE) was introduced into the film forming amine (FFA) formulation based on the unsaturated diamine N-oleyl-1,3-propanediamine (NOPDA). The optimal FFA formulation was determined by orthogonal experiment. The high corrosion inhibition efficiency of 92.1% and the images of scanning electron microscopy (SEM) and atomic force microscopy (AFM) confirmed the excellent corrosion inhibition effect of the improved FFA formulation in 1.0 M HCl acidic environment. The results proved that DEAE could promote the emulsification and dissolution of NOPDA in aqueous solution and therefore facilitate its adsorption onto carbon steel surface. The weight loss experimental results showed that the adsorption of the FFA inhibitor onto metal surface was endothermic and conformed to Langmuir isotherm model. Electrochemical impedance spectroscopy (EIS) analysis proved that a protective film was formed on the surface of carbon steel to prevent the transfer of charge. Contact angle measurements indicated that the film formed on the surface of the carbon steel was hydrophobic. According to X-ray photoelectron spectroscopy (XPS) analyses and thermodynamic calculation, it is inferred that the adsorption mechanisms mainly involved chemisorption, electrostatic attraction and hydrogen bonding. The results of this study provide a good reference for the application of unsaturated fatty diamine. • Weight loss and EIS experiments were carried out to investigate the anti-corrosion performance. • The emulsification and dissolution of NOPDA in water could be promoted by DEAE. • NOPDA-based formulation exhibited excellent corrosion inhibition performance in HCl. • FFA adsorption isotherm and thermodynamics were studied. • SEM, AFM and XPS analyses were performed and anti-corrosion mechanisms were inferred.

Exploring the corrosion resistance of epoxy coated steel by integrating mechanochemical synthesized 2D covalent organic framework

Organic anticorrosion coatings reinforced by 2D nanomaterials are attracting ever-increasing research interests due to their superior anticorrosion performances. However, the strong π-π and van der Waals (vdW) interactions make the conventional 2D nanomaterials difficult to realize homogenous dispersion in the coatings during coating preparation. To remedy this problem, in this work, we introduced 2D covalent organic framework (2D−COF) in epoxy resin (EP) to synergistically realize high dispersion and improve the corrosion resistance of EP coated steel, where the 2D−COF (TpPa-1) was mechanochemically synthesized from 1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine (Pa-1). The results show that the TpPa-1 can achieve self-dispersion in EP. Further analyses reveal that the self-dispersion of TpPa-1 in EP stems from the reactions between the amino groups in TpPa-1 and epoxy groups in EP. Moreover, the prepared EP/TpPa-1 composite coating coated steel presents superior corrosion resistace compared with pure EP coating due to the good dispersion of TpPa-1. The superior anticorrosion mechanism of the coated steel is unraveled by combining experiments and molecular dynamics simulations. The results show that the added TpPa-1 can effectively improve the compactness of the composite coating. This will on one hand lead to the lower diffusion rate of corrosive media, and on the other hand, enhance the adhesion strength between the composite coating and substrate. This work can trigger further studies to perform reasonable design of 2D−COF, and therefore, new anticorrosion coatings with superior physical-mechanical properties can be obtained.

Insight into the anti-corrosion mechanism Veratrum root extract as a green corrosion inhibitor

The anticorrosive effect of Veratrum root extract (VRE) as the inhibitor for copper corrosion in H2SO4 solution was studied by electrochemical experiments and quantum chemistry calculation. The electrochemical experiments manifested that VRE exhibited good anticorrosion performance at a range of tested temperatures, which was further manifested by surface characterizations. The results of the Tafel test indicate that VRE belong to mixed corrosion inhibitors, which can simultaneously control the cathodic and anodic reactions of the Cu electrode. When the concentration of VRE is 200 ppm, its anti-corrosion efficiency can reach 97%. Quantum chemical calculation was employed to manifest the mechanism of adsorption and the relationship between the electronic structure of inhibitors and their anticorrosion performance.

Corrosive wear and electrochemical corrosion performances of arc sprayed Al coating in 3.5% NaCl solution

PurposeThe purpose of this paper is to investigate the effects of load and speed on the corrosive wear performance of Al coating in 3.5% NaCl solution, which provided an experimental reference for the anti-corrosion engineering on offshore platforms.Design/methodology/approachA layer of Al coating was prepared on S355 steel using an arc spraying. The corrosive wear test was carried out with CFT–1 type surface property tester. The effects of load and speed on the corrosive wear performance of Al coating were investigated and the wear mechanism was also discussed. The electrochemical tests were conducted using a CHI660E type electrochemical workstation, the anti-corrosion mechanism was analyzed.FindingsThe average coefficient of frictions (COFs) of Al coating under loads of 1.5, 2.5 and 3.5 N are 0.745, 0.847 and 0.423, the wear mechanism is abrasive wear. The average COFs of Al coating at the speeds of 200, 400 and 600 rpm are 0.745, 0.878 and 0.617, respectively, the wear mechanism at the speeds of 200 and 400 rpm are abrasive wear, while that at the speed of 600 rpm is abrasive wear and fatigue wear. The anti-corrosion mechanism is the isolation of Cl– corrosion and cathodic protection of sacrificial anode.Originality/valueThis paper mainly studied corrosive wear and electrochemical corrosion performances of Al coating. This study hereby confirms that this manuscript is the original work and has not been published nor has it been submitted simultaneously elsewhere. This paper further confirms that all authors have checked the manuscript and have agreed to the submission.

Corrosion integrity of oil cement modified by environment responsive microspheres for CO2 geologic sequestration wells

In order to ensure the safe and effectiveness of CO2 geological storage, an environmental responsive polymer microspheres (ERPM) was prepared to improve the corrosion resistance of cement stone. The structure and environmental response characteristics of ERPM were characterized, and then the anti-corrosion performance and anti-corrosion mechanism for ERPM were discussed. The results shown that ERPM had good environmental response characteristics and temperature resistance. ERPM could effectively suppressed the corrosion rate and the damage degree of mechanical properties of cement stone. The corrosion integrity of cement stone was improved due to the acidic response characteristic and form polymer films of ERPM, which effectively shield the direct contact between corrosion medium and hydration products.

Preparation and study of graphite nanoplatelets/waterborne acrylate composite anticorrosive coating

Preparation of environmentally friendly waterborne acrylate composite anticorrosive coatings is carried out with the function filler of amin-opropyltriethoxysilane (ATPES)-functionalization graphite nanoplatelets (f-GNPs) introduced in waterborne acrylate resin. The function filler is characterized by XPS, and the XPS result shows that the ATPES is grafted onto the surface of graphite nanoplatelets (GNPs). SEM images show that GNPs are dispersed well in the coating. The measurement results of the anticorrosive properties of the coating suggest that when the filler loading of GNPs is 3.6 wt%, the anticorrosive performance of the coating is optimal, namely, the salt spray resistance time exceeds 240 h, and the corrosion potential is − 0.68 V. At this time, the GNPs mainly play a physical isolation. When the filler loading of f-GNPs is 2.8 wt%, the coating presents the best anticorrosive performance, and the salt spray resistance time is more than 600 h, the service time is up to 50 years, and the corrosion potential is − 0.66 V. The anticorrosion mechanism of the coating is caused by the physical barrier and coulomb block effect. The coating is very suitable for repairing the defects caused by physical damages.

Applications of graphene in anti-corrosion of metal surface

As an emerging material, graphene has become a research hotspot in the field of anti-corrosion because of its excellent chemical inertia and permeability resistance. In this paper, combined with the latest research results, the applications of graphene film and graphene powders in the field of anti-corrosion are discussed more comprehensively. First, the anti-corrosion mechanisms of graphene (mainly including barrier effect, shielding effect, corrosion inhibition synergy, enhancement of coating adhesion, cathodic protection, and self-healing effect) and its corresponding coating preparation methods (graphene film prepared by chemical vapor deposition method and composite coatings prepared with graphene powders) are introduced. Then, the influences of different factors such as defects, conductivity, oxidation degree, flake size, and content of graphene on the anti-corrosion performance are discussed. Finally, various methods are comprehensively compared with each other, and future development is prospected. This paper not only reviews the existing work, but also has a certain reference value for preparing graphene materials with better corrosion resistance in the future.

Corrosion inhibition of mild steel in 1M HCl using environmentally benign Thevetia peruviana flower extracts

The corrosion inhibition of Thevetia peruviana (Kaner) flower extract (TPFE) is evaluated for mild steel in 1M HCl solution using electrochemical, surface and computational demonstrations. Results showed that TPFE acted as a potential corrosion inhibitor and shows the highest inhibition efficiency of 91.24% at 200 mg/L concentration. Electrochemical studies suggest that TPFE acted as a mixed- and interface-type of corrosion inhibitor. The TPFE inhibits metallic corrosion through an adsorption mechanism that follows Temkin adsorption isotherm model. Adsorption mechanism of corrosion inhibition was further supported using AFM, SEM-EDX, FT-IR and UV–visible surface studies. Furthermore, the anticorrosive mechanism of major phytochemicals of the TPFE was studied using computational techniques: Density Functional Theory (DFT) and Molecular Dynamics (MD) simulations. Results showed that TPFE interacts with donor-acceptor interactions and its phytochemicals acquire the flat or horizontal orientations over the metallic surface.

Understanding the anticorrosion mechanism of phosphonium based ionic liquid for steel in brine water containing H2S and CO2

Carbon steel is being significantly considered for applications in the petroleum field. However, the corrosion of steel structures in the petroleum sector due to H2S, CO2 and brine solution is a limiting factor for the development of such metal. Here we use phosphonium based ionic liquid (i.e. Tributylmethylphosphonium Bis(trifluoromethanesulfonyl)imide, abbrev. PBIL) to control the corrosion of steel structures in brine water containing H2S and CO2 at pH of 2. The carbon steel suffers from high corrosion in the brine water containing H2S. Furthermore, H2S/CO2 system provides lower corrosive effects than a pure H2S system. The corrosive action of H2S/CO2 system becomes stronger at high temperatures. The incorporation of PBIL ionic liquid in brine water containing H2S and CO2 reduces the corrosion effects on steel structures, resulting in a much higher lifetime. PBIL ionic liquid adsorbs on steel structure surface to form a protective film, which is evidenced by Freundlich isotherm and confirmed by SEM and EDX tests.