Corrosion Of Mild Steel Research Articles

Experimental and molecular modeling approach on the corrosion behavior of mild steel in HCl solution with quinoxaline inhibitors

Two new quinoxaline derivatives namely (E)-3-(2-chlorostyryl)quinoxalin-2(1H)-one (CSQO) & (E)-3-(2-(thiophen-2-yl)vinyl)quinoxaline-2(1H)one (TVQO) were synthesized and identified through the following methods like infrared (IR) analysis, mass spectrometry,1H NMR and 13C NMR. Weight loss, electrochemical techniques [PDP&SIE], surface analytical techniques [SEM&UV-Visible], quantum chemical calculations [DFT], and MD simulations have all been used to examine the effectiveness of CSQO and TVQO in preventing the corrosion of mild steel. According to the findings of the experiments, the inhibitors CSQO and TVQO effectively suppress the corrosion of mild steel in 1 M HCl solution, with maximum corrosion inhibition of 97.0 and 95.5% at 10−3 M for CSQO and TVQO, respectively. Based on PDP investigations, CSQO and TVQO function as mixed-type inhibitors, and their adsorption on the MS surface follows the Langmuir adsorption isotherm and the mode of adsorption is chemisorption. Both surface investigations (SEM and UV-Visible) have validated the protective layer that developed on the metal surface. DFT calculations and MD simulations were used to study the association between inhibitor molecular structure [CSQO and TVQO] and inhibitory efficacy, and they closely match the experimental findings.

Innovative 8-hydroxyquinoline derivatives as corrosion inhibitors for mild steel in hydrochloric acid: a quantum chemical and experimental study

ABSTRACT This study explores the inhibitory action of two novel organic compounds, namely diethyl 1-((8hydroxyquinolin-5-yl)methyl)−2,6-dimethyl-4-(p-tolyl)−1,4-dihydropyridine-3,5-dicarboxylate (PR1) and diethyl 1-((8-hydroxyquinoline-5-yl) methyl)−2,6-dimethyl-4-(4-nitrophenyl)−1,4dihydropyridine-3,5-dicarboxylate (PR2), on mild steel (MS) corrosion in 1M HCl. Using a combination of quantum chemical and experimental methodologies, the study evaluates the performance of these inhibitors through electrochemical techniques, including potentiodynamic polarisation (PDP) and electrochemical impedance spectroscopy (EIS), complemented by surface analysis via scanning electron microscopy (SEM) and X-ray electron microscopy (EDX). Key findings reveal that both PR1 and PR2 exhibit a significant rise in protection performance with concentration, reaching an impressive peak of 95.3% at 10−3 M for PR2. The inhibitors demonstrate mixed-type inhibition properties and adhere to the Langmuir adsorption isotherm. Detailed surface analysis confirms the creation of a defensive film on the metal surface, correlating with the observed electrochemical results.

Exploring the performance of Coriandrum sativum extract as an effective corrosion inhibitor for mild steel in a [formula omitted] medium, and its sustainable application in the eco-friendly removal of heavy metals

This research investigated the performance of coriander seeds, for the first time, in two critical phenomena: wastewater treatment and corrosion inhibition in acidic environments. On one hand, the aqueous extracts from Coriandrum sativum seeds (CE) were evaluated for mild steel corrosion inhibition in a 2.0 M phosphoric acid medium using several techniques such as phytochemical analysis (GC-MS), potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy (SEM-EDAX) and theoretical analyses, including DFT calculations and Molecular Dynamic Simulations, further elucidated the major chemical components. First, the phytochemical analysis has proved that CE contains heteroatoms. Second, the electrochemical results indicate that CE behaves as a mixed type inhibitor and the corrosion reaction is controlled by charge transfer process. Finally, The theoretical calculations confirmed that the active compounds of CE can be adsorbed on the Fe (1 1 0) surface through physical patterns and by sharing charges with iron to form coordinate bonds. The acquired results have shown a strong correlation between corrosion inhibition efficiency that was about 93 %, SEM-EDAX and DFT parameters. On the other hand, the study examined coriander seeds (CS) in powder form as a removal of copper ions in aqueous solutions through Atomic Absorption Spectroscopy and Inductively Coupled Plasma analysis. The parametric study was effectuated by establishing the effect of contact time, adsorbent mass, solution pH and stirring speed. The removal rate was about 79 %. Regeneration studies showed that CS could be reused for five cycles without significant loss of effectiveness. SEM-EDAX analysis has proved the studied process.

First Principles Investigations of Mild Steel Corrosion Inhibition by Dopamine Derivatives in HCl Solution

First Principles Investigations of Mild Steel Corrosion Inhibition by Dopamine Derivatives in HCl Solution

Synthesis, characterization and corrosion inhibition evaluation of a new chalcone derivative 2-3-(3-hydroxyphenyl)-1-[4-(1H-imidazol-1-yl) phenyl] prop-2-en-1-one for mild steel corrosion in 1M HCl assessment with DFT and MD studies

The prime objective of the work focuses on the synthesis of novel chalcone derivative, the 2-3-(3-hydroxyphenyl)-1-[4-(1H-imidazol-1-yl) phenyl] prop-2-en-1-one (HIPP) and study its corrosion inhibition for mild steel in 1M HCl. Various spectroscopic techniques such as IR, 1H-NMR, 13C-NMR, and mass spectroscopy were used to confirm the formation of the synthesized chalcone. Distinct electrochemical techniques like potentiodynamic Tafel polarization and impedance spectroscopy were employed to investigate HIPP in 1M HCl as a mild steel corrosion inhibitor. The synthesized chalcone was checked in a temperature range varying from 30o C to 60o C. With increasing quantities of HIPP, it is noticed that there is an enhancement in calculated corrosion inhibition efficiency. The maximum inhibition efficiency obtained was found to be 94.3 % in the presence of 100 ppm at room temperature. Surface morphology of unhindered and inhibited HIPP was analysed using scanning electron microscopy (SEM), atomic force microscopy (AFM) and water contact angle (WCA) measurements. SEM investigation revealed that the inhibitor effectively protects the metal surface from aggressive corrosion. Atomic force microscopic images show the corroded MS surface roughness in the presence of HIPP reduced from 342.1 nm to 174.3 nm. Furthermore, the inhibitor's adsorption through electron-donor acceptor interactions was revealed by DFT calculations and MD studies.

Experimental and theoretical simulations to examine the influence of nonionic surfactant on the corrosion control of mild steel in hydrochloric acid

The increasing demand for corrosion prevention strategies that are both effective and sustainable is part of the research the background. Nonionic surfactants offer a potential replacement for traditional corrosion inhibitors. These surfactants are well-known for their low toxicity and biodegradability. The research involved conducting experimental tests (such as weight loss, polarization and impedance spectroscopy) and theoretical computations to investigate the role of nonionic surfactant (polyoxyethylene (7) tribenzyl phenyl ether) (PETPE) in controlling the corrosion of mild steel in hydrochloric acid (1.0 M HCl) environment. The results of the study demonstrated that PETPE exhibited significant corrosion inhibition properties for mild steel in HCl solution. The inhibition efficiency of PETPE was found to increase with increasing PETPE concentration. PETPE is an excellent corrosion inhibitor because it significantly reduces the rate of corrosion, as seen by the notable inhibition efficiency result (95.4%) at a relatively low dose of PETPE (100 ppm). Thermodynamic studies were used to discuss the fundamental mechanisms that control PETPE-acid interactions. The adsorption process followed Langmuir adsorption isotherm, indicating a monolayer adsorption of the PETPE on the mild surface. Theoretical computations confirm the strong inhibition behavior of PETPE. The innovative feature of this research is its comprehensive strategy, which integrates experimental studies and theoretical simulations to evaluate the impact of PETPE on the corrosion control of mild steel in hydrochloric acid. The combined effort has the ability to supply valuable knowledge into the mechanisms of corrosion that will lead to the establishment of powerful corrosion control strategies.

Synthesis of a new quaternary ammonium salt for efficient inhibition of mild steel corrosion in 15 % HCl: Experimental and theoretical studies

The corrosion phenomenon and its economic impacts can hardly be ignored in any application. This study synthesized a quaternary ammonium salt (3) containing hydrophobic dodecyl and electron-rich diallylbenzyl amine moieties to be used in 15 % HCl as a corrosion inhibitor of mild steel. Several techniques, such as 1H and 13C NMR, IR, TGA, and elemental analysis, have been used to characterize inhibitor 3. Popular corrosion measurement techniques, namely weight loss, potentiodynamic polarization techniques, and electrochemical impedance spectroscopy, have been used to determine the efficiency of inhibitor 3. At 303 K and a moderately low concentration of 50 ppm, the quaternary ammonium salt-based inhibitor demonstrated a maximum efficiency of ≈95.0 %. At elevated temperatures of 313, 323, and 333 K, the inhibition efficacy values were recorded as 91.3, 82.8, and 75.0 %, respectively. Adsorption isotherm study revealed that the adsorption of inhibitor 3 followed Langmuir adsorption isotherm. The value of ΔGads° was found to be – 40.19 kJ mol−1, indicating that inhibitor 3 became adsorbed via a mixed physi-chemisorption mechanism. A very high adsorption constant (Kads) of 1.53 × 105 L mol−1 suggested strong adsorption of inhibitor 3. The difference in activation energy (Ea) value of 42.4 kJ mol−1 between the control and the inhibited solution indicated an efficient adsorption of inhibitor 3. The ability of inhibitor 3 to retard both anodic and cathodic half-cell reactions was proved via open circuit potential and Tafel curves studies. Detailed discussions on the change in corrosion current densities (icorr), polarization (Rp) and charge transfer (Rct) resistances have been offered to discuss the inhibition efficiency. Water contact angle measurement showed a drastic increase in mild steel surface hydrophobicity following inhibitor 3 adsorption. SEM-EDX and XPS studies confirmed the definitive presence of inhibitor 3 on the mild steel surface. Density functional theory (DFT) studies revealed the frontier molecular orbitals with which the metal surface interacts. A detailed corrosion inhibition mechanism has been offered in the context of adsorption isotherm and DFT studies.

Experimental study on corrosion inhibition of mild steel using Mukia maderaspatana leaves extract as green inhibitor

In this work, investigations were conducted into the adsorption behaviour and inhibitory effect of Mukia maderaspatana leaves extract on the corrosion of mild steel in 1.5M HCl solution at several temperatures. The techniques included chemical methods (weight loss measurements), surface analysis (SEM, FESEM) and solution analysis (UV–visible spectrophotometric, ICP-MS) techniques. The examination of the data revealed that the efficiency of inhibition rose as the inhibitor's concentration increased and fell as the temperature increased. At 30 degrees Celsius, the concentration of inhibitor resulted in an increase in corrosion inhibition efficiency, reaching 99.02% efficiency at 8% concentration. The physical adsorption of the inhibitor on the metal surface was demonstrated by the adsorption free energy of the plant extract on mild steel. The conclusions above are supported by data from examinations of Scanning Electron Microscopy, FESEM, UV–visible and Fourier transform infrared spectrophotometry.

An electrochemical and theoretical approach towards the efficient microwave synthesis of imidazolium-based ionic liquids for unprecedented mild steel corrosion inhibition in 0.5 M H2SO4 solution

The inhibition potential of newly synthesized imidazolium-based ionic liquids (IL-1 and IL-2) on mild steel corrosion in a 0.5 M H2SO4 solution has been comprehensively investigated using gravimetric analysis, potentiodynamic polarization, and electrochemical impedance spectroscopy across various temperatures. Gravimetric analysis indicated that the adsorption of these inhibitors adhered to the Langmuir adsorption isotherm. Significantly, IL-2, featuring a longer alkyl chain, demonstrated superior inhibition efficiency (92.51 % at 303 K) compared to IL-1 (88.71 % at 303 K). Potentiodynamic polarization studies revealed a mixed-type inhibitory behavior, impacting both anodic and cathodic reactions. Surface morphological analyses via SEM and EDX confirmed the formation of a protective film on the mild steel surfaces, substantiating the corrosion inhibition capabilities of IL-1 and IL-2. The novelty of this research lies in the application of density functional theory (DFT) using the B3LYP method, which elucidated that the alkyl chain length at the N-3 position in imidazolium cation-based ionic liquids significantly enhances their inhibition potential. This mechanistic insight suggests that these ionic liquids effectively obstruct both anodic and cathodic sites, providing robust corrosion protection in a 0.5 M H2SO4 solution.

Achieving a super-strengthening functional composite coating from ZnO doped snail shell particulate for mitigation of mild steel towards improved microstructural, corrosion, and opto-electrical properties

Long-lasting protective coatings are essential, particularly under harsh operating conditions. Surface coatings provide a flexible alternative; electrodeposition is becoming an established approach for protecting steel. The intent of this study is to determine how effectively zinc oxide (ZnO) coatings for mild steel corrosion protection effect when integrated with snail shell particle (SSP). The experimental setup consisted of producing a coating bath with ZnO and SSP particles, then electrodeposting the mixture under conditions onto polished steel surfaces. The created coatings were subjected to an array of tests, including electrical conductivity and resistivity testing, morphological analysis using SEM/EDS, corrosion testing in a 1M HCl solution, hardness testing. The findings show that when SSP content increases, steel corrosion rates significantly decrease, suggesting improved corrosion resistance from 21.85(mm/yr) to 12.80(mm/yr), and polarization resistance of 4.47E+01(Ω) to 8.00E+01(Ω). Morphological examination shows that SSP particles are dispersed throughout the coating matrix, which promotes adhesion and stability. Also, coatings with more SSP show better electrical characteristics. Overall, the study shows how ZnO-SSP coatings can shield mild steel components from adverse conditions and have prospective uses in sectors where surfaces resistant to corrosion are needed.

New Benzimidazole derivatives as efficient organic inhibitors of mild steel corrosion in hydrochloric acid medium: Electrochemical, SEM/EDX, MC, and DFT studies

The corrosion of mild steel (MS), a widely used material in industry, represents a significant global challenge. In order to extend the durability of equipment, the use of corrosion inhibitors proves to be an effective solution, particularly in corrosive environments. In this research, two newly synthesized benzimidazole derivatives, namely 1-(cyclohex-1-en-1-yl)-3-[(3-phenyl-1,2-oxazol-5-yl)methyl]-2,3-dihydro-1H-1,3-benzodiazol-2-one (Benz1) and 1-(cyclohex-1-en-1-yl)-3-[(3-phenyl-4, 5-dihydro-1,2-oxazol-5-yl)methyl]-2,3-dihydro-1H-1,3-benzodiazol-2-one (Benz2), were evaluated as corrosion inhibitors for MS in 1 M hydrochloric acid solution. This study was conducted using both experimental methods and computational approaches. Potentiodynamic polarization diagrams (PDP) indicate that, depending on concentration effects, Benz1 and 2 function as mixed-type inhibitors, with a predominance of cathodic inhibition. The results of electrochemical impedance spectroscopy (EIS) show that the compounds tested offer high inhibition efficiencies of 96.32 % and 98.30 % at 10−⁴ M for Benz1 and 2, respectively. Inhibitor adsorption follows the Langmuir isotherm and involves chemisorption. SEM/EDX analyses confirm the presence of a protective film on the metal. In addition, DFT and Monte Carlo simulations reveal significant adsorption of the compounds on the MS surface, underlining their high potential as effective corrosion inhibitors.

Electrochemical and computational evaluation of hydrazide derivative for mild steel corrosion inhibition and anticancer study

In the present study the authors’ main goal is to avoid the corrosive attack of the chloride ions of 3.5% NaCl solution in saline medium on the mild steel (MS), by addition of small amount of a new derivative of the hydrazide called ligand (HL), as a corrosion inhibitor. This study had been achieved by employing different electrochemical measurements such as, open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentio-dynamic polarization (PDP) methods. The results of the electrochemical test (OCP), showed that, the open circuit potential of the mild steel in saline solution, was guided to more positive direction in presence of the ligand (HL), at its ideal concentration (1 × 10−3 M), compared to the (OCP), of the mild steel in absence of (HL). The results of the electrochemical methods, EIS and PDP presented that, the ligand (HL), was acted as a good corrosion inhibitor for hindering the corrosion process of the mild steel in 3.5% sodium chloride, as it was recorded a good percentage of the inhibition efficiency (77.45%, 53.41%, by EIS and PDP techniques respectively), at its optimum concentration (1 × 10−3 M). Also, the corrosion rate of the mild steel in the saline medium without (HL), was listed about (0.0017 mm/year), while in existence of (HL), was decreased to a value about (0.00061 mm/year). As well, some of electrical properties of (HL), and its derivative [Pd(II), Cr(III), and Ru(III)], complexes were investigated such as; the activation energy (Ea(ac)), which recorded values in the range of 0.02–0.44 (eV) range and electrical conductivity which listed values at room temperature in the range of 10−5–10−8 S.cm−1. The results of the AC and DC electrical conductivity measurements for (HL), and its derivative [Pd(II), Cr(III) and Ru(III)] complexes indicate semiconducting nature which suggests that these compounds could be used in electronic devices. Also, the complexes exhibited higher conductivity values than (HL). Photophysical studies showed good florescence properties of HL that indicated that it can be used to determine most of the drugs with no fluorescence properties by quenching and calculating quantum yield. Moreover, the hydrazide ligand (HL), has shown selectivity as an active anticancer candidate drug for both breast and colon cancer in humans. Density function theory demonstrated that, the frontier molecular orbital HOMOs of the complexes have exhibited similar behavior and the charge density has localized in the metallic region of all the studied complexes. Also, the values of the energy gap of the ligand (HL), and its complexes Pd(II), Cr(III) and Ru(III), had been arranged in this order HL > Cr(III) > Ru(III) > Pd(II). All characterization using different spectroscopic techniques were reported to elucidate the proposed structures such as; thermal analysis, elemental analysis of C, H, and N atoms, spectral analysis using IR, UV, 1H NMR techniques, scanning electron microscopy and energy dispersive X-ray analyses.

Assessment of Warionia saharea Essential Oil as a Green Corrosion Inhibitor for Mild Steel in HCl: Experimental and Computational Studies

The objective of this research work is the study of the inhibitory effect of Warionia saharea essential oil (WSEO) on the corrosion of mild steel (MS) in molar HCl solution, employing both experimental and theoretical methods. This inhibitory effect (IE) has been evaluated by using a combination of weight loss measurements (LW) and various electrochemical methods, such as open circuit potential (OCP), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) experiments. The LW results indicated that IE increased with inhibitor concentration, reaching 83.34% at 3.00 g/L. The PDP analysis suggested that WSEO functions as a mixed inhibitor, while in the EIS results the Rct values increased with inhibitor concentration to reach 165.8 Ω cm2 at 2.00 g/L, suggesting a defensive film formation by WSEO molecules over the metallic surface. The thermodynamic study demonstrated that the WSEO molecules adsorption on the MS surface followed a Langmuir isotherm, involving mixed physical and chemical (physicochemical) adsorption on the MS surface. Theoretical methods, including density functional theory (DFT) and molecular dynamics (MD) simulations, were employed to elucidate the inhibition mechanisms of the three main components of WSEO. The quantum chemical analysis, using density functional theory (DFT) and molecular dynamics (MD) simulations, showed a low ΔEgap value of 6.30 eV and a low adsorption energy (Eads) value on an Fe (110) substrate of −258 Kcal/mol for (E)-Nerolidol, indicating the significant contribution of this molecule to the overall corrosion inhibition effect of WSEO. The scanning electron microscope (SEM) analysis verified the presence of a protective film formed by the inhibitor on the MS surface. This study highlights the potential of WSEO as a sustainable and green corrosion inhibitor in acidic environments.

Chitosan grafted with gallic acid and cerium dioxide hybrid nanocomposites as environmentally friendly corrosion inhibitors for mild steel: An experimental and computational study

Chitosan grafted with gallic acid (CS-GA), along with CS-GA doped with CeO2 nanoparticles (CS-GA-CeO2) were synthesized as novel environmentally friendly mild steel corrosion inhibitors. The formation of these derivatives was confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), hydrogen nuclear magnetic resonance spectroscopy (1H NMR), and thermal analysis (TGA). Based on potentiodynamic polarization curves (PDP) measurements, the inhibitors acted primarily as hybrid inhibitors, while following the Langmuir adsorption theory model. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy(XPS) and 3D surface profiles, confirmed that CS-GA-CeO2 adsorbed on the mild steel forming a protective layer thus preventing the invasion of corrosive media. The corrosion protection mechanism of chitosan derivatives was investigated by molecular dynamics simulations. Electrochemical measurements were used to investigate the corrosion inhibition by CS-GA and CS-GA-CeO2 on mild steel in a 3.5 % NaCl solution. At room temperature, the highest inhibition efficiency (93.58 %) was achieved at 200 ppm CS-GA-CeO2. Modified chitosan nanocomposites were confirmed as promising corrosion inhibitors.

Experimental and Quantum Chemical Studies of a Green Corrosion Inhibitor for Mild Steel in Acidic Chloride Solution

AbstractA green corrosion inhibitor was prepared from the bio‐based platform compound 5‐hydroxymethylfurfural through a green synthetic route, which avoid the use of toxic reagent. The inhibition performance and mechanism of this compound for the corrosion of mild steel in 0.1 M HCl was investigated by using the weight loss experiments, polarization measurements, EIS measurements and quantum chemical calculations. The corrosion inhibition efficiency by weight loss measurement (ηWLM%) of this inhibitor can reach up to 90.3 % at 303 K with 1.2 mM concentration. Moreover, the electrochemical experiments revealed that this corrosion inhibitor acts as a mixed‐type inhibitor. Thermodynamic studies gave the values of the standard Gibbs free energy , fall within the range of −20 kJ/mol to −40 kJ/mol, suggested the adsorption of this compound is a spontaneous process involving both physisorption and chemisorption. In addition, quantum chemical calculations were conducted to further validate the formation of an effective absorption layer by this inhibitor on metal surfaces, which showed that the electron density iso‐surfaces of HOMO was mainly distributed on chloride ions, while LUMO tended to be distributed on furan rings and aldehyde groups. Besides, the other quantum chemical parameters of this inhibitor were also calculated to explore the molecular activity, such as, the molecular volume (ν, 333.105 Å), global hardness (η, 4.706 eV), global softness (σ, 0.2125 eV), electronegativity (χ, 4.93 eV), dipolemoment (μ, 13.1429 D) and vertical ionization energy (VIE, 7.2646 eV).

Corrosion Resistance Improvement of Mild Steel

Abstract Corrosion’s devastating consequences have become a big issue all over the world. One of the corrosion damage aspects are related to decontamination solutions which are essential for rapid degradation of toxic agents. The decontamination solutions should be non-corrosive to avoid deterioration of steel container. Decontamination solutions comprising have high chlorinating activity so they have a corrosive effect on mild which are used in fabrication of storage tanks. In this case, using inhibitors is one of the most effective strategies to limit the rate of corrosion. This work describes the effect of different compounds; (zinc chromate, cinnamaldehyde, sodium tripolyphosphate, zinc ortho-phosphate, ammonium molybdate and thiourea) on the rate of corrosion of mild steel within dichloroisocyanuric acid decontamination solution. Meanwhile, these inhibitors should not affect active chlorine content which is responsible for the decontamination process. By using kelthoff and AquaChec® methods for measuring active chlorine, it was found that only zinc chromate passed the tests. For measuring electrochemical behaviour of mild steel in decontamination solutions, different techniques were used. Zinc chromate inhibition on mild steel in a 0.5% dichloroisocyanuric acid solution at different temperatures (298–313 K) were studied utilising electrochemical impedance spectroscopy, weight loss, and potentiodynamic polarisation. The results reveal that zinc chromate is an excellent mild steel corrosion inhibitor in dichloroisocyanuric acid, with an inhibition efficacy of 96% at a concentration of 0.005 M. Finally, surface morphology of mild was also investigated using SEM.

Study of multifaceted eco-friendly nanoparticle zinc coating incorporation on mild steel.

Mild steel's versatile application in various fields makes it a pivotal material, yet its vulnerability to corrosion demands effective protection methods. This work explores the potential synergy between plantain peel (PP) and snail shell particle (SSP) nanoparticles when combined in a Zn–MgO matrix to improve corrosion resistance in mild steel coatings. After a thorough investigation of various bath compositions and process conditions, the ZnO–MgO–20SSP–20PP coating was found to have improved electrical characteristics, decreased thickness with high-quality films, higher hardness (78 HRB), and excellent corrosion resistance. Corrosion tests showed a notable decrease (∼70% for the ZnO–MgO–20SSP–20PP sample) in the rate of corrosion, and optical micrographs confirmed the coating's capacity to reduce damage. A reliable predictive model (ANOVA) was produced by mathematical optimization utilising a central composite design, which highlighted the interplay of SSP and PP concentrations on corrosion rate. This extensive study provides eco-friendly alternatives for improved mild steel corrosion prevention by showcasing the diverse contributions of SSP and PP nanoparticles.

Effect of substitution on corrosion inhibition properties of 4-(substituted fluoro, chloro, and amino) Benzophenone derivatives on mild steel in acidic medium: A combined Electrochemical, surface characterization and theoretical approach

Background: In this study, three mono-substituted Benzophenone (BP) derivatives, 4-Fluorobenzophenone (4-F.BP), 4-Chlorobenzophenone (4-C.BP), and 4-Aminobenzophenone (4-A.BP) were investigated using a combined electrochemical, surface characterization and theoretical approach. Methods: In experiment, the effectiveness of 4-F.BP, 4-C.BP, and 4-A.BP in inhibiting mild steel corrosion in a 1 N HCl solution were investigated using gravimetric measurements at several temperatures (303–333 K), electrochemical measurements (Potentiodynamic Polarization (PDP), and Electrochemical Impedance Spectroscopy (EIS)), UV–visible analysis, Surface morphology test (SEM and EDAX analysis, AFM analysis, water contact angle measurement, XPS analysis) as well as theoretical studies. Significant findings: Increase in the inhibitor concentrations (160, 200, 240 and 280 ppm) exhibited a maximum percentage of inhibition efficiency (IE %) of 83.75 %, 88.75 %, and 93.75 % for 280 ppm of 4-F.BP, 4-C.BP, and 4-A.BP respectively at 303 K. However, with increase in the temperature from 303 to 333 K, IE % furthermore reduced to 52.41 %, 57.24 %, and 66.20 % at 333 K. The potentiodynamic polarization plots revealed that all molecules acted as mixed-type corrosion inhibitors and had an exceptional ability to inhibit the anodic reaction. Moreover, Scanning Electron Microscopy (SEM), Atomic force microscopy (AFM), and Contact angle measurement (CAM) confirms the formation of protective layer on the metal surface by the chosen inhibitors. The X-ray Photoelectron Spectroscopy (XPS) data confirms the bonding interaction between the functional groups and the metal surface. Furthermore, Density Functional Theory (DFT) calculation and Molecular Dynamics simulations (MD) were carried out to understand inhibition's molecular/atomic mechanisms. In summary, the suggested benzophenone derivatives are effective and economical anticorrosion agents for mild steel surfaces exposed to aggressive environments.

Effect of pH on the controlled release of benzotriazole from halloysite clay nanotubes for corrosion protection of mild steel

Due to the increase in severe consequences of mild steel corrosion, the development of coatings with improvement in corrosion-resistant properties has become very essential. In this work, benzotriazole (BTA) was encapsulated into halloysite nanotubes (HNTs) for inhibiting the corrosion of mild steel surface. The BTA-encapsulated HNT exhibits pH-responsive properties over a wide range of pH. It was found that a large amount of BTA was released at pH 3 (48 %), followed by pH 7 (30 %) and least in the case of pH 10 (20 %). At neutral pH, a rapid release of BTA was observed during initial exposure, reaching a steady-state later, with no significant release further. A salt immersion test was carried out after immersing mild steel (MS) substrates in BTA-HNT nanopowder dispersion in 3.5 wt% NaCl at different pH. SEM images and EDS maps confirmed that corrosion product formation on MS surface at pH 3 was significantly more with corrosion pits along with HNTs throughout the surface. At pH 7 and 10, corrosion pits were observed with very few halloysite nanotubes on the surface. An optimum amount of BTA is required to inhibit corrosion, excessive release may cause more Cl− ions to penetrate, leading to more corrosion. Electrochemical data also reveals the same trend, where the icorr value was maximum for pH 3 (1.09 × 10−5 A/cm2) > pH 7 (4.74 × 10−6 A/cm2) > pH 10 (3.43 × 10−6 A/cm2). Therefore, results suggest that BTA-encapsulated HNT can be efficiently incorporated into the coating matrix for their controlled release to provide corrosion protection under varying neutral and alkaline marine environments.

Corrosion of Mild Steel and Galvanized Steel in SO2 Enclosures: The Incidence of Negative Gravimetric Corrosion Rates

Corrosion of Mild Steel and Galvanized Steel in SO2 Enclosures: The Incidence of Negative Gravimetric Corrosion Rates