Mild Steel Surface Research Articles

Synthesis characterisation and analysis of the corrosion resistance of a new epoxy resin onto mild steel in the presence of hydrochloric acid: practical and theoretical points of view

ABSTRACT In this work, we synthetised the tetraglycidyl ether L-(+) ribose (TGER). TGER was identified through nuclear magnetic resonance spectroscopy (NMR). The effectiveness of a novel epoxy resin derived from TGER in protecting mild steel from corrosion in hydrochloric acid has been evaluated. After 30 minutes of immersion, electrochemical impedance spectroscopy revealed that TGER could reduce mild steel corrosion, achieving an inhibition rate of 93% at 10−3 M. According to the Langmuir isotherm model, chemical bonding allows the compound to adhere to the mild steel surface. Molecular structure analysis using density functional theory (DFT) supports the observed inhibition efficiency. Furthermore, molecular dynamics studies indicated that the interaction energy of the TGER inhibitor increased, while radial distribution function analysis confirmed the chemical adsorption of the inhibitors onto the metal surface. Additionally, thermodynamic activation parameters suggested that the adsorption process on the metal surface was spontaneous. The synthesised TGER epoxy resin provided maximal protection of 93% at 10−3 M, and the epoxy functional groups improved the anti-polarisation efficacy of the molecule.

Mechanistic Insights into the Corrosion Inhibition Performance of Eco-Friendly Nitrogen and Boron Co-Doped Carbon Dots for Mild Steel in a 15% HCl Solution.

A novel and eco-friendly route to synthesize boron, nitrogen codoped carbon dots using aniline, citric acid, and boric acid as precursor materials has been used successfully to reduce mild steel corrosion. This report describes the detailed weight-loss experiments, electrochemical measurements, and surface morphology analysis conducted to explore the efficacy of B,N-CDs as a highly effective corrosion controller for mild steel (MS) protection in 15% hydrochloric acid (HCl). The findings specify that B,N-CDs significantly decreased the corrosion of MS and attained an inhibition capacity of up to 96.7% at 75 ppm. The protection of the MS surface occurs through the generation of a protective film through adsorption of the B,N-CDs. The corrosion inhibitor undergoes predominant physisorption, which is confirmed by the values of ΔGads. Electrochemical studies further established that B,N-CDs act as a mixed type corrosion inhibitor. Hence, the aforementioned carbon dots are both cathodic and anodic corrosion inhibitors for MS. The XPS of the inhibitors explained that it is of inorganic/organic hybrid nature of the protective film generated on the surface of the substrate. The findings represent a new highly effective corrosion inhibitor that outperforms most of the alternatives at lower concentrations.

Wetting behaviour of mixed surfactants on the mild steel surface

Wetting behaviour of mixed surfactants on the mild steel surface

A Novel Study on the Chemical Profiling of Okoubaka Aubrevillei Edible Seed Oil Using GC-MS Analysis and Evaluation of its Corrosion Inhibition Properties on Mild Steel Using Molecular Dynamic (MD) Studies

Tropical African parasitic tree species known as Okoubaka aubrevillei has both culinary and medical purposes. The oil in the seeds of this tree is abundant yet little is understood. Gas chromatographymass spectrometry (GC- MS) was used in this work to examine the chemical makeup and physical characteristics of Okoubaka aubrevillei seed oil and molecular dynamic (MD) simulations were used to assess the capacity of the oil to inhibit corrosion on mild steel. It was discovered that the oil contains additional components like sterols and phenolic compounds in addition to being high in unsaturated fatty acids, particularly linoleic acid (39.67 %). These substances function as antioxidants and may have positive impacts on human health. With a high adsorption energy value of -353.55 Kcal/ mol, it was also discovered that the oil could firmly adsorb on mild steel surfaces and offer a degree of protection against corrosion. The energy of the lowest unoccupied molecular orbital (ELUMO), the energy of the highest occupied molecular orbital (EHOMO), the energy gap (ΔE) between LUMO and HOMO, and the Mulliken charges on the backbone atoms were all determined through optimization with HOMO and LUMO energy values of -5.377 and -0.824 eV, respectively. The findings of this study point to Okoubaka aubrevillei seed oil as a possible edible oil source with great potential for mild steel corrosion inhibition and potential for use in a variety of applications.

Deposition of layers of ethanolic extract of waste pineapple crown on mild steel through drop casting and examination of their corrosion behavior

Corrosion causes serious damage to the metals and decreases their usefulness as well as economic values. Inhibitors are generally used to control corrosion of metals. However, synthetic inhibitors are being used in limited conditions due to environment and cost concerns. The waste natural materials (WNM) have become the preference choice of the scientists for corrosion prevention applications. A WNM provide a cost effective, efficient, and economic solution of corrosion of metals. The present work examines the effectiveness of a WNM, pineapple crown (PC), against the mild steel (MS) corrosion in 0.5 M sodium chloride (NaCl). PC has been extracted into ethanol (EEPC) and characterized by FTIR spectroscopy (FS) and UV-visible spectroscopy (US). The EEPC layers (1-3) are coated on MS through drop casting using simple set-up, and coated MS has been tested for corrosion prevention by open circuit potential (OCP), Tafel polarization curves (TC), and electrochemical impedance spectroscopy (EIS). The results have confirmed that EEPC layers significantly prevent MS in NaCl. However, the best performance is obtained for 2 layers of EEPC (80%, TC). The surface images are clicked by field emission scanning electron microscopy (FESEM), which shows that EEPC has covered most of the places on the MS surface after coating and effectively protected MS in NaCl. The similar observations are recorded with atomic force microscope (AFM). Based on the overall results, a mechanism for corrosion prevention has also been introduced.

An extensive analysis of isoindigotin derivatives as effective corrosion inhibitors for mild steel in acidic corrosive environments: An electrochemical and theoretical investigation

Isoindigo and its derivatives are frequently employed as active ingredients in pharmaceuticals and in solar cells, largely due to their distinctive structural characteristics, which render them a green substance. The utilization of its polymers as efficacious corrosion inhibitors for the safeguarding of mild steel exhibits considerable promise. In order to achieve this, a green and highly efficient isoindigo polymer (E)-7-(9,9-bis(3-(dimethylamino) propyl)-9H-fluoren-2-yl)-1,1′-bis(3-(dimethylamino) propyl)-[3,3′-biindolinylidene]-2,2′-dione (PIIDN-FN) was synthesized using a simple one-step polymerization reaction and subsequently employed as a corrosion inhibitor for the first time. In this work, its ability to inhibit the corrosion of Q235 when added to 1 M HCl medium was the subject of corresponding electrochemical tests and surface analyses (including SEM, AFM and XPS etc.). The results implied that PIIDN-FN was able to achieve a maximum inhibition efficiency of 94.52 % at a concentration of 100 mg L−1, and the inhibition efficiency was still close to 90 % even at a high temperature of 328.15 K. Moreover, the PDP results indicated that PIIDN-FN is a hybrid corrosion inhibitor, and it was determined that the adsorption of the material onto the carbon steel surface conformed to the Langmuir isotherm model. Furthermore, quantum chemical calculations (QC) based on density functional theory (DFT) and molecular dynamics simulations (MD) facilitated the elucidation of the inhibition mechanism. The findings of the theoretical investigation suggest that PIIDN-FN adsorbs as a film on the surface of mild steel due to its conjugated structure, forming a complex with iron and thereby providing effective protection for carbon steel.

Corrosion Inhibition of Mild Steel by Plumeria rubra Flower Extract: Electrochemical and Computational Study

AbstractThe corrosion inhibition efficiency of Plumeria rubra flower extract (PRFE) on 5LX70 mild steel in 4% NaCl aqueous medium was studied by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and density functional theory (DFT). The PRFE was analyzed by FTIR for the confirmation of functional groups in the extract molecules. EIS and PDP methods indicated that the corrosion inhibition was increased with an increase in the concentration of inhibitor, with a surface area coverage of 90.12%. Polarization results revealed that PRFE is a mixed‐type inhibitor. A maximum corrosion inhibition of 90.98% was achieved at 120 ppm of extract concentration. Quantum chemical parameters of the inhibitor molecules were calculated using the DFT method to ascertain the relation between the parameters and inhibition efficiency. Molecular descriptors like HOMO, LUMO, energy gap, absolute electronegativity, electrostatic surface potential, and so on, were determined, and found that the inhibitor molecules favorably formed a protective layer on the metal surface. The Mulliken charge analysis of the constituent atoms of selected PRFE molecules further supported in identifying the active sites for binding with the mild steel surface. Experimental results have confirmed that PRFE is a good corrosion inhibitor for mild steel which was further affirmed by the computational study.

Dichloromethane -methanol fraction of Mahonia nepalensis containing Berberine, Jatrorrhizine, and tetrahydroberberine as corrosion inhibitor for mild steel

A potentially superior alternative source of environmentally acceptable corrosion inhibitors for metallic materials is plant extracts. This study reports on the use of compounds separated from Mahonia nepalensis (MN) bark extract as an environmentally friendly corrosion inhibitor for mild steel (MS) in 1 M H2SO4. The organic layer was separated from MN bark extracts and then Berberine, Jatrorrhizine, and Tetrahydroberberine were identified and quantified by Liquid column mass spectroscopy (LC-MS) in dichloromethane (DCM) −Methanol fraction of Mahonia nepalensis. The DCM − Methanol fraction of extract was characterized by Ultra violet − visible spectroscopy (UV–Vis) and Fourier Transform Infrared (FTIR). The DCM-Methanol fractions in 1 M H2SO4 were applied to study corrosion inhibition of MS by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed above 91 % inhibition efficiency (IE) for DCM-Methanol fraction containing 2.12 ppm berberine, jatrorrhizine, and tetrahydroberberine at room temperature indicating that it is an effective and cheap candidate for the corrosion prevention of MS in industry. The potentiodynamic polarization demonstrated a reduction in current density without affecting the reaction mechanism but reduced the hydrogen reduction indicated by suppression in cathodic current. Based on polarization curves and open circuit potential, it exhibited mixed inhibitory behavior. Similarly, EIS analysis revealed a drop in double-layer capacitance accompanied by an increase in charge transfer resistance. EIS and a scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX) ascertain the adsorption of inhibitor molecules forming a protective layer on the MS surface.

Terminalia bellirica fruit shell extract by microwave assisted extraction as a green inhibitor for mild steel acid corrosion: insight from chemical, electrochemical and computational studies

In the current study, the corrosion protection role of ethanol extract of Terminalia bellirica fruit shell on Mild Steel (MS) in 0.5 M HCl solution was studied by using weight loss, Tafel plot, AC impedance and surface techniques. The existence of functional groups in the plant extract was confirmed with the aid of FT-IR spectroscopy technique. The presence of 31.12% of gallic acid in the Terminalia bellirica fruit shell extract was complemented with HPLC and LCMS results. The surface coverage and protection efficiency of Terminalia bellirica fruit shell extract were enhanced with its concentration and declined with solution temperature. The activation parameters such as activation enthalpy, entropy and change in Gibb’s free energy are related to adsorption process were calculated and discussed. The adsorption of Terminalia bellirica fruit shell extract was found to obey the Langmuir adsorption model. The process of adsorption of inhibitor molecules on the metal surface can be verified by using UV–Visible spectroscopy technique. The potentiodynamic polarization and impedance results suggest that, Terminalia bellirica fruit shell extract functioned by adsorption at metal (MS)-Corrodent (0.5 M HCl) interface, which blocks the both cathodic and anodic half reactions of the MS corrosion process. Theoretical approach by Monte Carlo (MC) simulations and quantum chemical study support the experimental findings and adsorption of extract of Terminalia bellirica fruit shell molecules on MS surface.

Synthesis, characterization, theoretical, and evaluation of eco-friendly phenytoin-based corrosion inhibitors for mild steel

This study explores the corrosion inhibition potential of two newly synthesized phenytoin-based compounds, (E)-2-(2-(2-chlorobenzylidene)hydrazineyl)-5,5-diphenyl-3,5-dihydro-4H-imidazol-4-one (2-ClPh-DDI) and (E)-2-(2-(2,4-dichlorobenzylidene)hydrazineyl)-5,5-diphenyl-3,5-dihydro-4H-imidazol-4-one (2,4-diClPh-DDI), in 1 M HCl solution. Both compounds exhibited remarkable inhibition efficiencies, reaching 97.7 % and 98.6 %, respectively. Comprehensive structural characterization was conducted using fourier-transform infrared spectroscopy, nuclear magnetic spectroscopy, and high-resolution mass spectrometry, both inhibitors demonstrated high purity and stability. Theoretical evaluations, including Monte Carlo simulation and density functional theory calculations, confirmed high reactivity and strong inhibition capabilities. Electrochemical measurements demonstrated a concentration-dependent inhibition effect, sustained up to 328 K. Adsorption isotherms revealed that these inhibitors effectively displace water molecules, forming a robust adsorbed layer that protects the mild steel surface. Surface analysis using microscopy confirmed the formation of protective layers and the presence of iron-inhibitor complexes, highlighting the compounds’ effectiveness in mitigating corrosion. The combined experimental and theoretical insights underscore the promising role of these phenytoin derivatives as eco-friendly corrosion inhibitors for mild steel.

Electrochemical and quantum chemical investigation on the adsorption behavior of a schiff base and its metal complex for corrosion protection of mild steel in 15 wt% HCl solution

This work evaluates the effectiveness of Schiff base derivatives, namely, 2,2'-((1E,1′E)-((2,2-dimethylpropane-1,3-diyl)bis(azaneylylidene))bis(methaneylylidene))diphenol (DAMD) and (2-((E)-((3-(((E)-2-hydroxybenzylidene)amino)-2,2dimethylpropyl)imino)methyl)phenoxy) zinc (HDMZ), as corrosion inhibitors for mild steel in a 15 % HCl solution. By employing a blend of experimental assessments and theoretical computations, such as electrochemical tests, morphological observations, and theoretical simulations, the study achieved an impressive up to 94.6 % inhibition efficiency. Notably, HDMZ exhibited significant protective properties. The results of PDP showed that both inhibitors act as mixed-type corrosion inhibitors. SEM surface analysis of the uninhibited and inhibited samples revealed the formation of a protective layer of inhibitor molecules on the mild steel surface to mitigate its corrosion. The Langmuir adsorption model verified the occurrence of dual adsorption, while theoretical simulations offered insights into the underlying interaction mechanisms. The identification of Schiff-based inhibitors reveals a pronounced synergistic effect in corrosion inhibition, marking a significant advancement in understanding corrosion control mechanisms. This study illuminates the process of forming covalent bonds between inhibitor molecules and iron atoms, presenting a hopeful path towards the advancement of corrosion inhibitors tailored for industrial use. The parallel adsorption configuration and mutual interactions form a stable structure, reinforcing the organic-metal bonds and enhancing both chemical and physical adhesion to the steel surface. These findings indicate that the synergistic effect of molecular interactions and polar-rich regions offers a promising strategy for designing functional hybrid materials.

In-depth investigation of corrosion inhibition mechanism: Computational, electrochemical, and theoretical studies of vanillin meldrum’s acid on mild steel surface in 1 M HCl

Vanillin Meldrum’s acid (VanMA) was successfully synthesized and thoroughly examined using techniques like elemental analysis, FTIR, NMR, UV–Vis spectroscopies, and single crystal X-ray diffraction. It crystallizes in a triclinic crystal system under the P-1 space group. A quantitative analysis of the intermolecular interactions in the crystal structures was performed using Hirshfeld surface analysis, which reveals that H···H contacts are the most significant contributing 43.2 % and the O···H/H···O contacts contributing 36.2 % of the total Hirshfeld surfaces. VanMA proved effective as a corrosion inhibitor in 1 M HCl, demonstrating a 62.19 % inhibition efficiency at an optimal concentration of 0.1 mM. It creates a protective layer on mild steel surfaces, adhering to the Freundlich adsorption isotherm (R2 = 0.9983) and displaying a physical adsorption mechanism (−12.72 kJ/mol). The corrosion inhibition efficacy of VanMA (0.1 mM) decreases in 1 M HCl as the temperature increases from 303 to 383 K. A shift towards physisorption is indicated by the increase in activation energy (Ea) from 12.37 to 16.42 kJ/mol. VanMA’s adsorption efficacy reduces at higher temperatures, increasing surface exposure and corrosion rates, but increasing activation enthalpy (ΔH° = 31.32 kJ/mol) and ΔS° = −113.63 J mol−1 K−1). The diameter of the semicircle rose as the concentration of VanMA increased, indicating that VanMA adsorption is responsible for the mild steel surface’s greater resistance to corrosion with increasing Rct values from 224 to 641 Ω cm2 and decreasing capacitance double layer (Cdl) values from 4.480 × 10−5 to 1.560 × 10−5 μFcm2, confirming VanMA’s efficacy as a corrosion inhibitor at 65.05 %. The SEM-EDX and AFM images show the smoother mild steel surface at 0.1 mM VanMA. VanMA was verified as a mixed-type inhibitor by showing shifts of less than 85 mV with respect to the blank PDP. The inhibition efficiency (IE%) increased up to 77.89 % while the icorr values decreased to 1.1850 × 10−5 A/cm2 as the VanMA concentration rose. In XPS, the presence of VanMA was identified by the presence of FeO (713.60 eV) and CO (287.93 eV), which signifies the adsorption of VanMA onto mild steel by the O atom and the negatively charged O ion via a mixed adsorption. DFT and Mulliken population analysis deduced that the VanMA interacted with the mild steel through mixed adsorption. VanMA adsorbs almost parallel to the Fe (1 1 0) surface, forming a barrier that protects from corrosion, according to the MD modeling. While the significant negative adsorption energy (−309.490 kcal/mol) verifies the stability and spontaneity of the adsorption process.

Synthesis investigation and exploring of new tetraglycidyl bisurea bisphenyl S polyepoxide as an excellent corrosion inhibitory resin for mild steel in 1M HCl environment: Comprehensive approaches

This work reports the synthesis of new epoxy resin namely tetraglycidyl bisurea bisphenyl S (TGBUBS). TGBUBS was characterized through using nuclear magnetic resonance (1H NMR and 13C NMR) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). TGBUBS was investigated as an excellent organic inhibitor for protecting the mild steel from corrosion in 1M HCl solution at different concentrations. Anticorrosion protection behaviors were evaluated and more discussed including different techniques such as potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and contact angle (CA) measurements. The obtained results showed that the TGBUBS exhibited inhibition efficiencies at lower concentration are 93.19 % (PDP) and 91.21 % (EIS), respectively. Further, PDP measurements indicated that the TGBUBS acted as a mixed-type inhibitor in 1M HCl solution. Furthermore, SEM and EDS analysis showed a significant reduction in the corrosion on the mild steel surface when the inhibitory epoxy resin was present compared to the blank solution (1M HCl). The effectiveness and interactions of the new epoxy resin on the mild steel surface were also predicted using DFT calculations and molecular dynamics (MD) simulations. The theoretical approaches are in agreement with the experiment results.

Synergistic corrosion inhibition of mild steel by chalcone derivatives and KI in acidic media via computational and experimental methods

The corrosion inhibition characteristics of chalcone 4-hydroxy-6-methyl-3-(3-phenylacryloyl)-2H-pyran-2-one derivatives with different functional groups (H, Cl, -CH3, -NO2, -OCH3) studied employing density functional theory (DFT). The study identified the CH-OCH3 derivative as the most effective inhibitor among the compounds analysed. This derivative was synthesized and characterized through IR, 1H NMR and 13C NMR spectroscopy. The CH-OCH3 inhibitor then studied for its mild steel corrosion inhibition capability using Electrochemical and surface analysis in 1 M HCl. CH-OCH3 inhibitory efficacy rises in proportionately with their concentration, according to electrochemical results and reaches 85.4 % at 10−3 M. Potentiodynamic polarization revealed that it operates as mixed-kind of inhibiting nature. CH-OCH3 adheres to the Langmuir isotherm when they bind over the mild steel surface. The deposition of the inhibitors on metal surface is additionally verified by surface study utilizing AFM. Additionally, the influence of KI addition over CH-OCH3 inhibition property has been studied.

Direct graphene growth on low-alloy and mild steel surfaces controlled by carbon solubility and surface microstructural transformations during chemical vapor deposition

This study demonstrates for the first time, graphene grown directly on the iron-rich surfaces of bulk 8620 low-alloy and 1018 mild steel by chemical vapor deposition, a key step toward developing thin graphene coatings with strong graphene-steel bonding. Low growth temperatures of 660 °C–680 °C, were used to manipulate the steel's carbon solubility, confining carbon diffusion and microstructural transformations to the surface regions, with the bulk relatively unchanged. For 1018, a growth temperature of 680 °C resulted in a multilayer graphene coating with 80 % coverage. The alloying elements in 8620 improved graphene formation by influencing the surface microstructure transformations at these growth temperatures, with graphene coverage up to 95 %. The surface microstructure for 8620 affected graphene formation, seen in growths at 660 °C where a few-layer graphene coating formed from a cementite surface layer, and for growths at 680 °C where multi-layer graphene covered a pearlite dominant surface microstructure. Contact angle measurements confirmed the hydrophobicity of the graphene coating and electrochemical testing by potentiodynamic polarization and electrochemical impedance spectroscopy confirmed the 101 mV improvement to corrosion potential and an increase in impedance up to 18.23 kΩ. These detailed results regarding the direct growth of graphene as a coating layer on highly oxidation-sensitive steel surfaces suggest that this process is achievable through manipulating carbon solubility at the steel's surface by controlling temperature, alloy composition and surface microstructure transformations. These methods could be leveraged in developing protective graphene coatings for various iron-based alloys.

Exploring the potent corrosion inhibition properties of phenolic Schiff bases on mild steel in acidic environments, part A: coupling experimental and theoretical investigations.

In this study, we conduct a comparative investigation into the corrosion inhibition properties of two Schiff base compounds, namely 4,4'-((1E,1'E)-(ethane-1,2 diylbis(azaneylylidene))bis(methaneylylidene))diphenol (PSB5) and (1E,1'E)-N,N'-(ethane-1,2 diyl)bis(1-(4-nitrophenyl)methanimine) (PSB6), on mild steel in an acidic environment. The inhibitory efficiency and adsorption behavior of the inhibitors were assessed through electrochemical and gravimetric analyses. The inhibitors' deposition was further verified by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The findings of electrochemical tests demonstrate that these chemical compounds are potent inhibitors, with 96.5% inhibition provided by PSB5 at 10-3M. Therefore, PSB5 and PSB6 inhibitors are likely of mixed-form, as evidenced by changes in their Ecorr values of 59.8 mV and 33.0 mV, respectively when compared to the blank solution. Furthermore, the adsorption of these inhibitors onto the MS surface, as determined by the Langmuir adsorption isotherm, yielded free energy values of - 38.40 kJ mol-1 for PSB5 and - 35.20 kJ mol-1 for PSB6. These findings highlight a robust and spontaneous adsorption process for both inhibitors. Surface analysis using SEM-EDS revealed the preservation of the mild steel surface morphology and the adsorption of inhibitors. Theoretical investigations utilizing density functional theory (DFT) and molecular dynamics (MD) simulations supported and complemented the experimental findings. This research enhances the understanding of the corrosion protection potential of Schiff base compounds and their potential applications in various industries.

Enhancing corrosion resistance of mild steel with a hybrid surface coating: Film-forming zinc titanate/oleic acid composites

Coatings made from ceramic materials have shown remarkable effectiveness in preventing surface corrosion on mild steel (MS) surfaces. The coating's stability was enhanced by incorporating various elements into the matrix. This study incorporated an organic fatty acid, specifically oleic acid (OA)into the zinc titanate (ZT). It forms a ZT/OA hybrid film-like coating on the MS surface. The synthesized ZT/OA nanomaterials were thoroughly characterized using PXRD, FT-IR, and SEM. The cubic spinel structure of ZnTiO3 and its spherical morphology were revealed from these techniques. The ZT/OA composites were applied to the surface of mild steel, and a film was formed under ambient conditions at a temperature of 150 °C. An investigation was conducted on the electrochemical corrosion behaviors of ZT/OA composites in three electrode systems using both saline and acidic mediums. This study involved measuring the impedance and Tafel polarization corrosion data. The results indicate that the ZT40 (60 wt% oleic acid-doped) sample Showed a significantly higher resistance of 37638 Ω cm2, coupled with an impressive inhibition efficiency of 99.3 % under saline conditions. Furthermore, under acidic conditions, the ZT40 sample exhibited excellent performance, as evidenced by the results of 691 Ω cm2 and 97 % inhibition efficiency.

Synthesis of polyaniline tannate-modified carbon nanotubes by oxidative copolymerization as highly efficient corrosion inhibitors for mild steel in HCl solution

Corrosion is a prevalent issue in industrial production, directly impacting the production process and causing severe damages. To mitigate this problem, corrosion inhibitors are highly desired. Herein, a novel type of nano corrosion inhibitor, referred to as PTCNT, was synthesized through an oxidative copolymerization method utilizing aniline, ammonium persulfate (APS), and tannic acid (TA)-modified multiwalled carbon nanotubes (MWCNTs). The results demonstrated that the PTCNT effectively inhibited the corrosion of mild steel in 1 M HCl solution, achieving the corrosion inhibition efficiency of 90.6 % at the concentration of 75 mg/L. Characterization results implied that the PTCNT adsorbed onto the surface of the mild steel, forming a protective shielding layer. Potentiodynamic polarization measurements proved that the PTCNT functioned as the hybrid corrosion inhibitor. Furthermore, the adsorption of PTCNT on the mild steel surface was investigated using adsorption isotherm and adsorption kinetic modeling. Quantum chemical calculations were used to elucidate the adsorption mechanism of PTCNT. These findings raise new avenues for the development of highly efficient corrosion inhibitors for the mild steel in HCl solutions.

Corrosion resistance and wear behavior of CoCrFeNiMn@Gr high entropy alloy-based composite coatings prepared by laser cladding

In this study, we utilize laser cladding to apply a CoCrFeNiMn HEA with 2 wt.% few-layer graphene (Gr) coating onto the surface of Q235B mild steel. Alcohol stirring method was used for HEA and Gr preparation of composite powder. Raman spectroscopy and energy dispersion spectroscope (EDS) indicate the successful mixing of HEA and Gr powders, with Gr adhering to the surface of the HEA powder in a lamellar structure. The X-ray diffraction (XRD), scanning electron microscope (SEM), EDS, and Electron backscatter diffraction (EBSD) analyses revealed that grain refinement and the formation of fine carbide-hard phases in the HEA/Gr coating improve microhardness and wear resistance. The average Schmidt factors of the coating decreased from 0.47 to 0.45 with the addition of Gr, indicating enhanced resistance to plastic deformation and anisotropy. Nanoindentation experiments demonstrated that the HEA/Gr coatings exhibit superior resistance to plastic deformation, effectively enhancing the coating’s durability against spalling under stress and wear conditions. The microhardness of the HEA/Gr coating increased by 99.25%, and the wear rate decreased by 86.31% compared to the HEA coating alone. The open circuit potential (OCP), linear polarization curve, Tafel curves, electrochemical impedance spectroscopy (EIS), and Mott-Schottky tests all indicated that the HEA/Gr coating possesses superior corrosion resistance. X-ray Photoelectron Spectroscopy (XPS) results suggest that the passivation film of the HEA/Gr coating, which contains more oxides and less hydroxide, is more protective and denser, thereby slowing the corrosion rate.

Synthesis and Electrochemical Properties of Oleylamine as a Sour Saline Corrosion Inhibitor Under Laminar Flow at 40 °C.

In this study, the synthesis of a long-chain aliphatic amino compound and its sour corrosion inhibition properties were reported. Oleylamine was obtained through the reaction of 4-(Aminomethyl) pyridine with 1-chloro-octadecane. The identification and characterization of reaction products were carried out through Fourier transform infrared spectroscopy (FTIR) and gas chromatography/mass spectroscopy (GC-MS). Oleylamine was tested as a sour corrosion inhibitor for steels. Different concentrations of oleylamine (0, 5, 10, 25, and 100 ppm) in a sour saline electrolyte were analyzed. The dynamic anticorrosive behavior of oleylamine on carbon mild steel (AISI 1018) surfaces was evaluated using a laminar flow of 100 rpm and tested with potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) measurements. After electrochemical testing, the surface of the steel specimens that were used was characterized with Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The electrochemical results of the anticorrosive efficiency of oleylamine for steel showed an exponential behavior as a function of inhibitor concentration. At a concentration of 20 ppm of the inhibitor, the anticorrosive efficiency did not show any significant changes. However, at 100 ppm of the inhibitor, an efficiency of over 95% was achieved. After the electrochemical tests, the surface of the steel samples with the inhibitor revealed the formation of an inhibitor layer that prevented the corrosion of the steel.