Anti-corrosion Mechanism Research Articles

Design and properties of environmental anticorrosion coating based on m-aminobenzenesulfonic acid/aniline/p-phenylenediamine terpolymer

The waterborne biocompatible alkyd/polyaniline (WARA/PANI) coatings have gained a unique position in anticorrosion coating industry. However, the dispersion and compatibility between WARA and PANI still remain big challenge. Here copolymerization of aniline with aniline derivatives was adopted to prepare PANI, m-aminobenzenesulfonic acid-aniline (SPANI) copolymer, and SPANI copolymer end-capped with p-phenylenediamine (SPANIP terpolymer) aqueous dispersions. The chemical structure of PANI, SPANI and SPANIP was characterized by FT-IR spectra, XRD and UV–vis spectra. PANI displayed spherical particle morphology, while SPANI and SPANIP showed interconnected rod-like structure. The water dispersibility for SPANIP was significantly superior to that of PANI and SPANI, as well as the compatibility between SPANIP and WARA. The as-prepared SPANIP/WARA films also displayed enhanced thermal property and water resistance. The impedance modulus of SPANIP3/WARA coating increased by 4 orders in comparison with WARA coating, and increased by 2 orders compared with PANI/WARA and SPANI/WARA. In comparison with PANI/WARA, Ecorr of SPANIP/WARA shifted from -805 mV to -401 mV, Icorr of SPANIP/WARA decreased by one order, and the corrosion inhibition efficiency increased from 73.8% to 94.3%. SPANIP/WARA coating was also endowed with improved long-term corrosion resistance, and the anticorrosion mechanisms were proposed.

Enhanced anticorrosion performance of copper by novel N-doped carbon dots

Researchers recent reported that N-doped carbon dots (NCDs) effectively inhibit steel corrosion in HCl solution, whereas the action mechanism is still uncertain to date. Herein, novel NCDs have been prepared using a facile hydrothermal method. Combining electrochemical, weight loss, and micromorphology techniques, the resultant NCDs were found to effectively suppress copper corrosion in aggressive H2SO4 medium. NCDs–adsorption film was formed on copper substrate as a barrier that could prevent transportation of corrosive particles. The relevant anticorrosion mechanism of NCDs was proposed in detail, which could provide powerful guidance to design and synthesis new nanomaterials for metal protection from corrosion.

Anticorrosion mechanism of Cr-doped nickel-base alloy in Br/O environment: a DFT study

ABSTRACTDensity functional theory was used to investigate the anticorrosion mechanism of Cr-doped nickel-base alloy in Br/O environment. The adsorption properties including adsorption energy, bond length and electron structure of Br/O on Ni and Cr-doped Ni surfaces have been investigated. We find that the O atom has bigger adsorption activity than the Br atom. The oxide film can be preferentially formed on the Cr-doped nickel-base alloy surface under the coexistence of Br and O atoms. By exploring the interactions between Br and NiO (111) or Cr2O3 (100) surfaces, we demonstrate that oxide films could prevent Br from erosion. Results indicate that Cr2O3 has stronger corrosion resistance than NiO. The corrosion resistance mechanism of Cr-doped nickel-base alloy is summarised into two processes, i.e. competitive adsorption and adsorption inhibition.

Surface coordination and excellent anticorrosion performance of strontiumapatite nanocomposite

A mass-produced, simple and scalable self-heating-based method for the manufacture of surface coordination strontiumapatite (SP) nanocomposite with excellent corrosion resistance is proposed. The reaction heat released from the formation of SP material increases the solubility of benzotriazole (BTA) which achieves reasonable distribution of system energy. The BTA is firmly adhered on the SP by SrN coordination bond, which acts as barrier impeding on the penetration of the corrosive medium. Scan electron microscopy (SEM) and X-ray diffraction (XRD) were employed to characterize coating morphology and chemical composition. Meanwhile, electrochemical impedance spectroscopy (EIS) data show that the resultant resistance of strontiumapatite/benzotriazole (SPB) nanocomposite coating was 3.02 × 104 Ω cm2, which was improved by 601.8% compared with SP material. The improvement of corrosion performance is attributed to the synergistic anticorrosion mechanism that includes the shielding effect, extension of charge transfer paths and formation of multiple passivation films. The method for organic and inorganic synergistic material provides ideas for the design and synthesis of anticorrosive materials.

Preparation and properties of polymeric surfactants: A potential corrosion inhibitor of carbon steel in acidic medium

The polymeric surfactants were synthesized using allyl glycidyl ether, acrylamide, butyl acrylate and sodium allylsulfonate by radical polymerization and applied as corrosion inhibitor of carbon steel via weight loss method. The structure of polymeric surfactants was confirmed by FT-IR and NMR. The surface activity of polymeric surfactants was characterized by surface tension and wetting power. The anticorrosion mechanism of polymeric surfactants was confirmed by anticorrosion efficiency, the Gibbs adsorption free energy, SEM, AFM and XPS. The experimental results show that with the increase of the amount of polymeric surfactants, the corrosion resistance efficiency increases gradually, which proves that it is an effective corrosion inhibitor. The preparation process of the polymeric surface activity is simple which can be used for industrial production.

A comparative study of nanoscale poly N-(vinyl) pyrrole in polyvinyl butyral coatings for the anti-corrosion property of zinc: Nanotubes vs nanoparticles

Poly N-(vinyl) pyrrole (PNVPY) nanotubes (NTs) and nanoparticles (NPs) were prepared via a UV-catalyzed green chemical oxidative method in the presence of cetyltrimethylammonium bromide (CTAB) and polyvinyl pyrrolidone (PVP) as soft templates, respectively. The chemical structure of the PNVPY nanostructures was characterized by FTIR spectroscopy, UV–vis absorption spectra and 1H-NMR spectroscopy. The morphologies of PNVPY nanostructures were observed by the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was indicated that PNVPY NTs had an outer diameter less than 200 nm and a length in microscale. PNVPY NPs had an average diameter of 30 nm. Moreover, a series of anti-corrosion coatings on zinc were prepared by blending nanostructured PNVPY and carbon black with polyvinyl butyral (PVB) matrix to investigate the effect of the morphologies of PNVPY nanostructures on the corrosion protection ability. The surface and cross-sectional morphologies of the anti-corrosion coatings were observed by optical microscopy and SEM. Open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements showed that PNVPY NPs with a larger surface area and a smaller scale yield a better anti-corrosion performance than PNVPY NTs in the coatings. The probable anti-corrosion mechanism of these anti-corrosion coatings was proposed.

Anticorrosion performance of Zn-Al-Gr/waterborne epoxy composite coatings on mild steel

Graphene (Gr) has attracted much attention due to its excellent performance. There are various studies about Gr composite materials; however, the influence of Gr on anticorrosion mechanism was not explored widely. In this paper, the Gr was prepared by oxidation-reduction method and was modified with 3-aminopropyl triethoxysilane for better dispersion. Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Micrograph (SEM) were utilized to characterize the microstructure of coating and the modification of Gr. X-Ray Diffraction (XRD) was employed to analyse the phase composition of the coating. The anticorrosion performance of coating was investigated by employing polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that the uniformly dispersed Gr nanosheets in Zn-Al-Gr/waterborne epoxy enhanced the protection property of the composite coating. Furthermore, the corrosion resistance properties of the composite coating were optimized by tuning the concentration of the added Gr.

Investigation of diffusion alloying time on electrochemical behavior and conductivity of Nb-modified AISI 430 SS as PEMFC bipolar plate

Purpose The purpose of this paper is to improve the surface electrical conductivity and corrosion resistance of AISI 430 stainless steel (430 SS) as bipolar plates for proton exchange membrane fuel cells (PEMFCs), a protective Nb-modified layer is formed onto stainless steel via the plasma surface diffusion alloying method. The effect of diffusion alloying time on electrochemical behavior and surface conductivity is evaluated. Design/methodology/approach In this work, the surface electrical conductivity and corrosion resistance of modified specimen are evaluated by the potentiodynamic and potentionstatic polarization tests. Moreover, the hydrophobicity is also investigated by contact angle measurement. Findings The Nb-modified 430 SS treated by 1.5 h (1.5Nb) presented a lower passivation current density, lower interfacial contact resistance and a higher hydrophobicity than other modified specimens. Moreover, the 1.5 Nb specimen presents a smoother surface than other modified specimens after potentionstatic polarization tests. Originality/value The effect of diffusion alloying time on electrochemical behavior, surface conductivity and hydrophobicity of modified specimen is evaluated. The probable anti-corrosion mechanism of Nb-modified specimen in simulated acid PEMFC cathode environment is presented.

Effect of Nano-SnS and Nano-MoS2 on the Corrosion Protection Performance of the Polyvinylbutyral and Zinc-Rich Polyvinylbutyral Coatings.

In this paper, four composite coatings of nano-SnS/polyvinylbutyral (PVB), nano-MoS2/PVB, nano-SnS-Zn/PVB, and nano-MoS2-Zn/PVB were prepared, and their anti-corrosion mechanism was analyzed by experimental and theoretical calculations. The results of the electrochemical experiments show that the effect of nano-MoS2 on the corrosion protection performance of PVB coating is better than that of nano-SnS in 3% NaCl solution, and that the addition of Zn further enhances this effect, which is consistent with the results of weight loss measurements. Furthermore, the observation of the corrosion matrix by the field emission scanning electron microscope (FESEM) further confirmed the above conclusion. At last, the molecular dynamics (MD) simulation were carried out to investigate the anti-corrosion mechanism of the nanofillers/PVB composites for the copper surface. The results show that both nano-SnS and nano-MoS2 are adsorbed strongly on the copper surface, and the binding energy of nano-MoS2 is larger than that of nano-SnS.

Understanding the adsorption and anticorrosive mechanism of DNA inhibitor for copper in sulfuric acid

Abstract Deoxyribonucleic acid (DNA) was investigated for suppressing copper corrosion in 0.5 M H2SO4 through electrochemical measurement, microscopic surface observation, X-ray photoelectron spectroscopy (XPS) analysis and molecular dynamics (MD) simulation. Results indicate that DNA acts as an effective cathodic-type inhibitor that mainly suppresses cathodic reaction by forming anchored DNA-adsorption film. The film shows active blocking effect, obeys the Langmuir adsorption model and involves physisorption and chemisorption. The MD simulation gives the new insights at molecular level and indicates the formation of an interesting double barrier of DNA molecule on the Cu (111) surface due to its unique twist structure.

Anti-corrosive properties of quercetin and its derivatives on Fe(111) surface: a quantum chemical approach

Quercetin, and its derivatives are potential anti-corrosive agents for mild steel in HCl as evaluated by recent weight-loss techniques as well as electrochemical studies. But the actual mechanism of anticorrosion and mode of adsorption of these inhibitors have not yet been explored. In the present work corrosion inhibition activity of quercetin, and its derivatives, are explored by density functional theory (DFT) in order to obtain inhibition efficiencies and reactive sites of corresponding compounds as possible corrosion inhibitors on Fe(111) surface. Quantum chemical parameters such as frontier molecular orbital (HOMO, LUMO) energies, charge distribution, electron affinity, ionization potential, dipole moment, hardness, softness, electronegativity, electrophilicity and charge transfer between quercetin and Fe(111) surface have been evaluated. Adsorption energies of quercetin derivatives on iron surface revealed that the binding is mostly chemisorptive in nature. There is close agreement between theoretical and experimental values of corrosion inhibition efficiency. Thus, suitably designed quercetin derivatives can act as good anti-corrosive agents on iron surface.

Preparation and Properties of Chemically Bonded Ceramic Coatings Reinforced by GO-TiO2 composites

Graphene oxide (GO) decorated by titanium dioxide (TiO2) was fabricated and introduced into the chemically bonded ceramic coatings as a nanofiller. The analysis of the results of thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electronic microscopy (SEM), and transmission electron microscopy (TEM) show that TiO2 has decorated on the surface of GO by chemical bonds. Furthermore, the effect of incorporating GO-TiO2 on properties of ceramic coatings was investigated. The results show that GO-TiO2 achieved a homogeneous dispersion and compatibility in ceramic matrix without obvious cracks. The potentiodynamic polarization test was conducted to investigate the influence of GO-TiO2 on the corrosion behavior. The results demonstrated that corrosion resistance of ceramic coatings remarkably enhanced by adding GO-TiO2. Furthermore, the anticorrosive mechanisms of ceramic coatings with GO-TiO2 were tentatively discussed.

Preparation and corrosion behavior of chemically bonded ceramic coatings reinforced with ZnO-MWCNTs composite

Zinc oxide decorated multi-walled carbon nanotubes (ZnO-MWCNTs) was synthesized by sol-gel method. The structure and morphology of ZnO-MWCNTs were characterized by x-ray diffraction analysis (XRD), and transmission electron microscopy (TEM). The results showed that ZnO was well dispersed on the surface of MWCNTs. Furthermore, ZnO-MWCNTs was added into chemically bonded ceramic coatings on stainless steel to improve its anticorrosion properties. The analysis of XRD showed that no new phase was formed with the addition of ZnO-MWCNTs. Besides, there was no cracks between MWCNTs and ceramic matrix and MWCNTs was covered by ceramic gel resulted by the reaction between the aluminum phosphate (AP) binder and ZnO on the surface of MWCNTs, which means that MWCNTs and the ceramic matrix were well connected by ceramic gel, and resulting in the perfect bonding strength. In addition, the influence of ZnO-MWCNTs on the corrosion resistance of ceramic coatings was investigated by the potentiodynamic polarization. The results indicated that the application of ZnO-MWCNTs can effectively improve the corrosion resistance of ceramic coatings. Furthermore, the anticorrosive mechanisms of ceramic coatings with ZnO-MWCNTs were tentatively discussed.

Theoretical investigation on the photoelectrochemical anticorrosion mechanism of SnO2–TiO2nanotube

In this work, the calculated electron density difference, Bader charge analysis and the density of states (DOS) of SnO2–TiO2-nanotubes (NTs) indicate that the electrons are transferred from the Ti atoms of TiO2into the O atoms of (SnO[Formula: see text] in SnO2–TiO2-NTs and the supported (SnO[Formula: see text] cluster acts as the role of storage for photogenerated electrons excited from TiO2-NTs, which is in good agreement with experimental results that the SnO2–TiO2-NTs composite films have higher photocurrent density for photocathodic protection of 304 stainless steel (304SS). The theoretical investigations provide a plausible explanation for the photoelectrochemical anticorrosion mechanism of SnO2–TiO2-NTs using periodic density functional theory (DFT).

Synergistic effect of homogeneously dispersed PANI-TiN nanocomposites towards long-term anticorrosive performance of epoxy coatings

Novel polyaniline-titanium nitride (PANI-TiN) nanocomposites were synthesized by one step chemical oxidation polymerization at a low temperature and PANI-TiN/epoxy coatings with enhanced corrosion resistance were obtained based on the synergistic effect of TiN nanoparticles and PANI nanorods. PANI-TiN nanocomposites and resultant epoxy coatings were characterized by Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), Raman and X-ray photoelectron spectroscopy (XPS). Their anticorrosion performance in a 3.5 wt.% NaCl aqueous solution was investigated by the electrochemical impedance spectroscopy (EIS) and polarization curves. The results indicated that the corrosion resistance of PANI/epoxy coatings can be highly enhanced by introducing TiN nanoparticles to the PANI nanorods and the PANI-TiN/epoxy composite coating with 0.4 wt.% TiN (mass ratio to epoxy) exhibited the best corrosion protective performance, whose corrosion potential (Ecorr = −0.338 V) was positively shifted by 0.235 V compared with pure epoxy matrix (Ecorr = −0.573 V), and the corrosion current density was reduced by two orders of magnitude. The chemical structure of the rust layer and the anticorrosion mechanism were studied via X-ray diffraction analysis (XRD) and XPS. TiN nanoparticles showed a remarkably inhibiting effect on the agglomeration of PANI nanorods in epoxy coating. The corrosion resistance was attributed to the mixed mechanism of “passivation effect” of highly dispersed PANI and “labyrinth effect” of TiN nanoparticles.

Towards Understanding the Anticorrosive Mechanism of Novel Surfactant Based on Mentha pulegium Oil as Eco-friendly Bio-source of Mild Steel in Acid Medium: a Combined DFT and Molecular Dynamics Investigation

Today, due to the increasingly stringent European directives concerning the use of molecules with certain toxicities towards the environment or their users, the essential oils, extracts, and molecules derived from plants exhibiting the characteristic of being biodegradable can be considered as a source of green corrosion inhibitors instead of harmful synthetic chemicals. The present work was devoted to testing the essential oil extracted from Mentha pulegium leaves(M1) as a corrosion inhibitor for C-steel in 1 mol/L HCl solution using both electrochemical techniques and gravimetric measurements for the evaluation of the inhibition efficiencies at different temperatures. The results obtained showed that the inhibition efficiency increased with an increase in M1 concentration to reach a maximum value of 92.21%. We sought to determine the molecule responsible for this high efficiency, starting with the analysis of oil chemical composition by gas chromatography coupled with mass spectrometry. This analysis revealed that menthol(M2) and isomenthol(M3) were the principal constituents. In order to identify the molecule responsible for the inhibition and explain the protection mechanism involved, quantum chemical calculations and Monte Carlo simulations were used to explain the interaction of menthol, the major constituent of M1 with the Fe-surface. To practically confirm these results, we studied the action of 1 mol/L HCl on steel with and without the addition of M2 by both methods(gravimetric and electrochemical study). A very high efficiency was obtained, an efficiency of 94.90% at 10‒3 mol/L, which was retained for a long exposure time, and slightly decreased in function of temperature. Finally, a good correlation between the experimental data, theoretical calculations, and SEM studies was obtained, which denied that the M1 efficiency was only a result of a synergy effect and confirmed the high efficiency of Mentha oil and its main component(menthol) as a strong ecological inhibitor of corrosion.

Development of Characterization and Analysis Methods for Graphene Modified Coatings for Tubing

With the further deterioration of the oil and gas exploitation environment, the corrosion of tubing becomes an intractable problem. Therefore, choosing suitable anticorrosive coating is of great significance to the safe operation life of tubing and reduce economic cost. Effect addition of appropriate graphene in coatings can significantly improve its corrosion resistance of the coating. However, most of the applied research are focus on marine heavy corrosion condition; the relationship between the corrosion mechanism and performance of graphene coating for tubing is not clear, probably due to difficulty in the characterization of the organizational structure characterization of the graphene modified coating. In the present work, Typical methods of the graphene coating characterization: Scanning Electron Microscope (SEM) with EDS, Transmission Electron Microscope (TEM), Atomic Force Microscope (AFM), X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) will be introduced, and the application prospect of the coating will be discussed. It indicated that the single characteristic method cannot analysis the structure and morphology information of graphene anticorrosion coating comprehensively. Flexibly use of a variety of characterization methods to study the anticorrosion mechanism and performance of the graphene modified coating for tubing is a better choice. The graphene modified anticorrosive coating for tubing is with the potential of wide applications.

Corrosion Protection of Graphene-Modified Zinc-Rich Epoxy Coatings in Dilute NaCl Solution

In order to hold the excellent corrosion resistance of zinc-rich epoxy coatings with reduced zinc content, five types of graphene modified zinc-rich epoxy coatings (G-ZRCs) were prepared. The effect of zinc content on the corrosion protection behaviors of G-ZRCs was investigated using electrochemical impedance spectroscopy (EIS). Open circuit potential (OCP) was also utilized to deepen the understanding of the anticorrosion mechanism of the as-prepared composite coatings. The results confirmed that addition of 0.3 wt % graphene could make the coating with 40 wt % (G-40ZRC) and 55 wt % zinc (G-55ZRC) provide cathodic protection for a short period of time. The EIS and OCP results showed a dominant physical barrier protection mechanism for the coatings without zinc (G-ZRC), while there was a mixed mechanism for G-40ZRC and G-55ZRC and a dominant cathodic protection mechanism for the coatings with 70 and 85 wt % zinc (G-70ZRC and G-85ZRC). Furthermore, the graphene modified zinc-rich coatings and corresponding corrosion products immersed in a 3.5% NaCl solution for 100 days were also characterized, which could further reveal anticorrosion mechanisms of the graphene modified zinc-rich coatings and the passivation effect of polyaniline (PANI).

Anti-corrosion behaviors of epoxy composite coatings enhanced via graphene oxide with different aspect ratios

Graphene oxide (GO) has a wide application prospect in the field of metal protection due to its good dispersion, chemical activity and physical barrier property. Herein, graphene oxide sheets with different aspect ratio were first prepared by simply controlling the procedure of chemical exfoliation and then used to fabricate GO/epoxy composite coatings. The morphology and structural features of as-prepared GO sheets were characterized by Raman spectroscopy, X-ray diffraction and atomic force microscopy. The dispersion and anticorrosive performances of GO with different aspect ratios incorporated in epoxy-based waterborne composite coatings were investigated by Raman spectroscopic mapping, electrochemical measurements and scanning vibrating electrode technique. The results demonstrated that the different types of GO showed homogeneous dispersion in epoxy resin and GO with higher aspect ratio exhibited larger corrosion protection potential. Furthermore, the anti-corrosion mechanisms for composite coatings enhanced via GO with different aspect ratio were tentatively proposed, which indicating that the GO sheets with higher aspect ratio provided a more tortuous permeation path for corroding medium and thus displayed better corrosion resistance.

Electrochemical, DFT and MD simulation of newly synthesized triazolotriazepine derivatives as corrosion inhibitors for carbon steel in 1 M HCl

The inhibitive action of three newly synthesized triazolotriazepine derivatives, namely, 9‑ethyl‑6‑methyl‑7H‑1,2,4‑triazolo[4,3‑b][1,2,4‑triazepin‑8(9H)-one (TTY), 7,9‑didecyl‑6‑methyl‑7H‑1,2,4‑triazolo[4,3-b][1,2,4]triazepin‑8‑one (TTY4), and 7,9‑ditetradecyl‑6‑methyl‑7H‑1,2,4‑triazolo[4,3‑b][1,2,4]triazepin‑8‑one (TTY5) for carbon steel in 1 M HCl is investigated using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and surface analysis techniques. The results show that the corrosion of carbon steel in HCl solution is efficiently inhibited by these new organic inhibitors. The adsorption of tested inhibitors on carbon steel surface is found to be spontaneous and obeyed the Langmuir adsorption isotherm. The anti-corrosion mechanism of these new inhibitors on iron was further revealed by quantum chemical calculations and molecular dynamics simulations. In agreement with the experimental data, theoretical results showed that the order of inhibition efficiency is TTY5 > TTY4 > TTY.