Corrosion resistance behavior of PEDOT nanocomposite coatings for steel material

Silane coatings for mitigation of microbiologically influenced corrosion of mild steel

BACKGROUNDThis study enhancing the corrosion resistance of mild steel (MS) by incorporating photo‐catalyst‐doped graphitic carbon nitride (g‐C₃N₄) nano‐sheets containing silver (Ag) and oxygen (O₂) into a solar light‐active photoelectrochemical anticorrosion paint with polyester (PE). The objective is to provide sacrificial anode protection through visible light activation.RESULTSThe developed paint forms a uniform film on the MS surface, effectively providing anodic protection under visible light. Characterization techniques, including energy‐dispersive X‐ray spectroscopy (EDX), transmission electron microscopy (TEM), Fourier‐transform infrared spectroscopy (FTIR), and UV–Vis spectroscopy, confirm the molecular structure of the nano‐sheets. Corrosion resistance, assessed through weight loss measurements and open circuit potential (OCP) tests, shows significant improvement with the addition of Ag/g‐C₃N₄ and Ag‐O₂/g‐C₃N₄ nano‐sheets at an optimized concentration of 15 mg. The protection efficiency is ranked as follows: O₂‐g/C₃N₄ > O‐g/C₃N₄ > Ag‐O₂/g‐C₃N₄ > Ag‐g/C₃N₄ > g‐C₃N₄. After 28 days of immersion in seawater, MS coated with O₂/g‐C₃N₄ exhibited the least weight loss, with an inhibition efficiency of up to 99%. Electrochemical impedance spectroscopy (EIS) further demonstrated enhanced coating resistance for the O₂/g‐C₃N₄ coating (Rct = 3.76 kΩ.cm2, Rcoat = 1.69 kΩ.cm2) compared to pure PE (Rct = 0.005 kΩ.cm2, Rcoat = 0.096 kΩ.cm2).CONCLUSIONThe synthesized O₂/g‐C₃N₄ and Ag‐O₂/g‐C₃N₄ nano‐sheets exhibit high surface areas and enhanced water dispersibility, which contribute to significant corrosion protection of MS. The electrochemical performance, including weight loss and OCP measurements, highlights the potential of these nano‐sheet photo‐catalysts in advancing corrosion resistance technologies, with broad implications for materials science and engineering applications. © 2024 Society of Chemical Industry (SCI).

Vibrational Spectroscopy and electrochemical study of MCuP2O7 (M = Ba, Ca and Zn), improvement of corrosion resistance of mild steel in 1.0 M HCl medium

Polyaniline (PANI), polypyrrole (PPy) nanofilms, PANI/TiO2 and PPy/TiO2 nanocomposites were synthesized electrochemically on Al1050 electrode. The formation of PANI and PPy nanofilms and PANI/TiO2 and PPy/TiO2 nanocomposites was characterized by Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), UV–visible absorption spectroscopy (UV–Vis), scanning electron microscopy (SEM), energy dispersion X-ray analysis (EDX), and electrochemical impedance spectroscopy (EIS). The comparative morphologic, spectroscopic and electrochemical properties of the prepared PANI and PPy nanofilms and nanocomposites were investigated in this study. The effectiveness of polymer and nanocomposite films in preventing the corrosion of Al1050 was tested in 3.5 % NaCl solution. For corrosion tests, anodic polarization curves and EIS were used to investigate their corrosion protection capability in saltwater solution. The highest, low frequency capacitance values were obtained as CLF = 60.76 and 12.8 mF cm−2 for PANI/TiO2 and PPy/TiO2 nanocomposites, respectively. The results of these studies revealed that the corrosion protection efficiency (PE) of the PANI/TiO2 (PE = 97.2 %), PPy/TiO2 (PE = 97.4 %) nanocomposites coated on Al1050 electrode was higher than that of PANI (PE = 96.4 %), PPy (PE = 94.9 %) and uncoated Al1050 electrodes. These nanocomposites can be used in airplanes, space technology, automobiles, electronics, and building sectors, as well.

PurposeThe purpose of this study was to investigate the polyacrylic polymer/Al2O3 as a new nanocomposite coating to protect brass and Al-bronze in 3.5% NaCl and the role of alumina formulation on their protection efficiencyDesign/methodology/approachThe corrosion efficiency of the nanocomposite coating (NCC) was evaluated by open circuit potential and electrochemical impedance spectroscopy (EIS).FindingsThe protection efficiency was more in the case of Al-bronze even for the same formulation of alumina NCC indicated the Cu substrate contribution. The Cu oxides in alloys and Al2O3 from the NCC and Al-bronze were responsible for this protection.Originality/valueAll the techniques supported each other, the presence of alumina was responsible for the corrosion protection efficiency.

Studying various mixtures of 3-aminopropyltriethoxysilane (APS) and tetraethylorthosilicate (TEOS) silanes on the corrosion resistance of mild steel and adhesion properties of epoxy coating

Insight into the corrosion resistance of mild steel in an acidic environment in the presence of an organic extract: Experimental and computational approach

Optimization of cold plasma process parameters for organosilicon films deposition on carbon steel: Study of the surface pretreatment effect on corrosion protection performance in 3 wt% NaCl medium

Inhibitor effect of succinic acid on the corrosion resistance of mild steel: electrochemical, gravimetric and optical microscopic studies

In the present paper, cerium nitrate salt was used as a green inhibitor to improve the corrosion resistance of mild steel in 0.1 M Na2SO4 solution. To increase the barrier effect and film stability of the protective layer, polyethylene glycol (PEG) was added. The corrosion tests were evaluated using d.c polarization techniques and electrochemical impedance spectroscopy. The composition and morphology of the sample surface were characterized using Raman spectroscopy and MEB/EDS analysis. The results show that the presence of PEG improved relatively the corrosion resistance of mild steel due to the removal of cracks, the pores blocking the formed film and the enhancement of adhesion and compactness of the cerium‐based film. Consequently, the protective film became more coherent on the steel surface. Furthermore, the potentiodynamic polarization indicated that the Ce3+/PEG system behaved as a mixed‐type inhibitor with the dominant effect of the cathodic part.

This study investigates the morphological and electrochemical properties of aluminum (Al) nano-coatings deposited on mild steel substrates using a vacuum thermal evaporation technique. The primary aim was to enhance the corrosion resistance of mild steel through controlled deposition of Al films with varying thicknesses (4 nm, 6 nm, 8 nm, 10 nm, and 60 nm). Morphological characterization was performed using Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM). While electrochemical behavior was assessed through Linear Polarization Resistance (LPR), Tafel analysis, and Electrochemical Impedance Spectroscopy (EIS) in a 0.5 M NaCl solution. Results revealed that surface morphology and roughness improved significantly with increasing Al thickness, with the 60 nm sample showing the most uniform and continuous coating. Electrochemical tests demonstrated enhanced corrosion resistance indicated by increased impedance values and reduced corrosion current densities at greater film thicknesses. The 60 nm coating exhibited optimal performance were reduced the corrosion rate by nearly 20% compared to the uncoated sample. X-ray Diffraction (XRD) confirmed successful Al deposition with distinct crystalline peaks observed in thicker films. The findings suggest that vacuum evaporated Al nano-coatings are highly effective in improving the surface integrity and corrosion resistance of mild steel, making them suitable for applications in harsh environments.

Mild steel continues to be the most extensively used construction material in several industries and constructions. However, corrosion of mild steel in aggressive environments is a major concern. Under the tremendously increasing demand for improving the coatings strategies because of the environmental concerns due to some of the traditional coatings, silane pre-treatments have been emerging as one of the effective solutions, among other strategies. Different approaches, such as adding particles of metal oxide (such as SiO2, ZrO2, Al2O3, TiO2 and CeO2), incorporating plant extracts and impregnating 2D materials into the coatings, have been employed for durable corrosion resistance, including for mitigating enhanced corrosion due to the presence of bacteria. This review discusses the critical mechanistic features of silane coatings such as the role of hydrolysis and condensation in the bonding of silanes with metal surfaces. The factors that influence the performance of the silane coatings for corrosion resistance of mild steel are discussed. In particular, this review provides insight into silane coatings for mitigating microbiologically influenced corrosion (MIC) of mild steel.

Synthesis and characteristics of alkyd resin/M-Porphyrins nanocomposite for corrosion protection application

Trisodium phosphate-loaded magnesium‑aluminum layered double hydroxides/oxidized-multiwalled carbon nanotubes self-assembled 2D-nanohybrid for designing a multifunctional smart epoxy nanocomposite

The study is aimed at exploration of a silane-based alternative to the hazardous chromate conversion coating (CCC) presently employed for aluminium alloy AA2024-T3 with a focus on optimising surface preparation and microstructure for coating performance. The corrosion performance of bis-(triethoxysilylpropyl)tetrasulphide silane as a conversion coating on aluminium alloy AA2024-T3 and its principal constituent phases namely AI-Cu(-Mg) solid solution and intermetallic compounds AhCuMg and AhCu2Fe, has been examined. The study included evaluation of the effects of various surface pretreatments on the electrochemical behaviour, topography and surface potential of AA2024-T3 and its constituents. Different methods of surface preparation/polishing and the effect of metallurgical processing intricacies (aging, supersaturation and quenching medium) on the electrochemical behaviour of the phases representing AA2024-T3 matrix were examined. The study also included evaluation of the formation and stability of M-O¬Si bond for AA2024-T3, its matrix and elemental constituents, through application of self-assembled monolayers (SAMs). The electrochemical behaviour of the surfaces polished by mechanical and chemical techniques, and the effects of metallurgical processing intricacies were examined by measurement of open circuit potential (OCP) in O.6M NaCI aqueous solution by flat-cell and micro-cell potentiostats, and surface potential measurement in air employing Scanning Kelvin Probe Force Microscopy (SKPFM). Surface pretreatment (alkali treatment, alkali and desmutting treatments, and boiling water treatment) studies involved measurement of OCP, surface topography by Atomic Force Microscopy (AFM) and surface potential by SKPFM. The performance of silane coated AA2024-T3 and its constituents was examined by DC polarisation studies, 30-day electrochemical impedance spectroscopy (EIS) in O.6M NaCI solution and salt spray tests (168 h, 5% NaCl, 35-37°C) according to ASTM B 117. The formation and stability of the metal M-O-Si bond for AA2024-T3 and constituents was examined through deposition of self-assembled monolayers of long hydrocarbon chain silane and evaluation of stability in H20, O.lM NaCl and O.6M NaCI as a function of immersion time. The most remarkable finding of the work was the observation that a boiling water pretreatment prior to silane application produced a coating of exceptional corrosion performance. The corrosion rate in DC polarisation test (typically of 0.002f.lAcm-2) was as much as one and half orders of magnitude lower than that for benchmark chromate conversion coating (CCC) (typically 0.098f.lAcm-2). The boiling water treatment resulted in a thin film (typically ~600nm thickness) of hydrated alumina Ah03.xH20 (pseudo boehmite, PB) on AA2024-T3 and all constituent phases with the exception of AhCuMg (S). The pseudoboehmite film comprised a dense network of flake-like crystals oriented approximately normal to the metal surface and exposing a large surface area to the coating system. It is suggested that the large surface area may promote extensive M¬O-Si bonding between the pseudoboehmite layer and the silane molecules to improve the effectiveness of the subsequent coating. The silane-coated secondary phase constituents did not perform as satisfactorily as the coated alloy matrix (AI-Cu solid solution) or the coated alloy AA2024-T3 itself. The reasons appeared to be associated with the absence of pseudoboehmite layer on AhCuMg (S-phase) and a less dense network of pseudoboehmite microstructure on AhCu2Fe. £IS study showed that the AA2024¬T3IPB/siiane system maintained higher impedance as compared to AA2024-T3/CCC during the 30-day period of test in the entire frequency range (O.OIHz-550kHz). The performance of the AA2024-T3IPBIsilane coating system in standard salt spray tests was also superior when compared to AA2024-T3/CCC. Other notable findings of the study included observations of: 1. Nobility associated with abrasive entrapment in aluminium during mechanical polishing for preparation of a standard surface. 2. Variations in OCP due to processing effects related to solute supersaturation, aging behaviour and choice of quenching medium. 3. Choice of boiling water pretreatment as a corrosion retarding process. The investigation of SAMs on AA2024-T3, AI-Cu solid solution and elemental Cu and Mg, exposed to water and NaCI solution, showed that silane bonds to all the constituents of the aluminium alloy AA2024-T3. All the SAMs were susceptible to destabilisation by water and chloride solution. However, Mg was most susceptible to attack by the chloride solution in terms of kinetics of stability. The presence of PB delayed desorption of SAMs.