Corrosion Inhibition Mechanism Research Articles

ZnO doped PAMAM for asphalt improvement as anti-corrosive coatings.

Asphalt is widely used as a coating resin due to its excellent adhesion strength and cost-effectiveness; however, its limited corrosion protection necessitates enhancement. In this study, poly(amidoamine) (PAMAM), combined with zinc oxide (ZnO) nanoparticles, was incorporated into the asphalt matrix to improve its anticorrosive properties. Various ratios of PAMAM-ZnO nanocomposite (1, 2, 4, and 6% by weight) were added to the asphalt binder, with the materials characterized using XRD, ¹H-NMR, and SEM techniques. The 2% PAMAM-ZnO/asphalt ratio exhibited the most significant improvement, achieving a corrosion protection efficiency (η%) of 97.93%, as confirmed by Tafel analysis, and a charge transport resistance (RCT) of 75.91 Ω cm² according to electrochemical impedance spectroscopy (EIS) data. A combination of barrier formation and sacrificial protection drives the corrosion inhibition mechanism. The PAMAM-ZnO nanocomposite forms a highly uniform layer on the carbon steel surface, creating an effective physical barrier that prevents the penetration of corrosive agents, thereby minimizing defects like pinholes. This barrier effect is complemented by the sacrificial protection provided by the ZnO nanoparticles, which are more reactive than the underlying steel and preferentially interact with corrosive ions (e.g., chloride ions). This interaction leads to the formation of stable ZnO corrosion products, which enhance the barrier and reduce the likelihood of corrosion on the steel surface. Additionally, PAMAM facilitates the even distribution and strong adhesion of ZnO within the asphalt matrix, ensuring a durable protective layer. The synergic impact between the polymer barrier and sacrificial ZnO protection results in the exceptional corrosion resistance observed in the 2% PAMAM-ZnO/asphalt formulation, offering a promising approach for advanced anticorrosive coatings.

Corrosion behavior of high manganese steel by iron-oxidizing bacteria in wastewater at the bottom of liquefied natural gas storage tanks

High manganese steel is a new generation of material for the fabrication of liquefied natural gas (LNG) storage tanks. The corrosion behavior of high manganese steel induced by iron-oxidizing bacteria (IOB) living in wastewater from LNG tanks bottom was investigated. The results revealed that IOB can induce a generation of a dense and thick biotransformation film on the steel. Interestingly, the biotransformation film could be able to reduce the corrosion rate of high manganese steel by 71% and alleviate the formation of corrosion pits. A corrosion inhibition mechanism is postulated, elucidating the protective role of the iron-manganese oxide composite biofilm.

Carbon dot aggregates: a new strategy to promote corrosion inhibition performance of carbon dots

The corrosion of metal not only produces serious economic losses and environmental pollution but also threatens equipment safety. Carbon dots (CDs) exhibit outstanding inhibition properties to availably retard the corrosion of metal. However, the present CDs-based corrosion inhibitors still fail to fully exert the environmentally friendly and low-cost merits of CDs. To address this issue, CD aggregates (CDAs) prepared by low-cost and eco-friendly CDs are developed as novel corrosion inhibitors for the first time, and their corrosion inhibition mechanism is disclosed. Specifically, CDAs with excellent long-term dispersion stability are synthesized by solvothermal treatment of CDs formed by citric acid and urea. CDAs at only 200 mg/L provide a corrosion inhibition effect of 90.38% for Q235 carbon steel in 1 mol/L HCl solution, approximately 1.53 times higher than that of CDs (59.21%). Moreover, the corrosion inhibition mechanism of CDAs is proposed through the analysis of adsorption isotherm, examination of corrosion morphologies, and theoretical calculations. That is, CDAs physically and chemically adsorb on the carbon steel surface, mainly hindering its anodic reaction, thus retarding the corrosion of carbon steel. This research firstly verifies the corrosion inhibition potential of green and low-cost CDAs and provides a novel strategy to promote the corrosion inhibition performance of CDs, promoting the progress of aggregate-based corrosion inhibitors.

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.

Experimental and Computational Insights into the Effects of -NH2 and -Cl Functional Groups on the Copper Corrosion Inhibition by Benzotriazole

The influences of -NH2 and -Cl groups on the copper corrosion inhibition in 0.5 M H2SO4 solution by benzotriazole were studied using experimental methods and density functional theory calculations. Mass loss tests, potentiodynamic polarization, and surface morphology analyses revealed notable differences: while unmodified benzotriazole showed an inhibition efficiency of 76.6%, the -Cl derivative increased this to 87.6%, whereas the -NH2 derivative dropped it to 61.0% at the concentration of 5 × 10−4 M. Density functional theory calculations indicated these differences are not due to electronic properties or inhibitor-copper interaction energies but rather to the inhibitor’s influence on the oxygen reduction reaction, especially O2 and H2O adsorption. The -NH2 group formed strong hydrogen bonds with O2 and H2O, reducing oxygen reduction inhibition, while the -Cl group repelled O2, resulting in enhanced inhibition. Free energy analysis of the oxygen reduction reaction supported these findings. These new insights into benzotriazole derivatives’ copper corrosion inhibition mechanisms offer valuable guidance for developing next-generation corrosion inhibitors.

Fabrication of Mo-encapsulated stainless steel by powder metallurgy and assessment of localized corrosion resistance

As a source of corrosion inhibitors, 2.5% Mo powder was mixed with Type 304L stainless steel powder and spark-plasma sintered to a fabricate Mo-encapsulated Type 304L stainless steel. The Mo particles formed a core/shell structure. The localized corrosion resistance of the fabricated Mo-encapsulated Type 304L stainless steel was compared with those of spark-plasma-sintered Type 304L and Type 316L stainless steels. Potentiodynamic polarization in 0.1 M NaCl suggested that the Mo cores could release molybdate, which acts as an inhibitor. However, the shells did not dissolve, preventing the Mo-enriched particles from acting as pit initiation sites. Similarly, the surface of the Mo core dissolved during dip-and-dry cycles using 0.1 M NaCl, but the shell was less prone to dissolution. Although the fabricated Mo-encapsulated stainless steel did not contain Mo as a solid solution, its rust resistance was equivalent to that of spark-plasma-sintered Type 316L stainless steel. In potentiodynamic polarization, the initiation potential for localized corrosion of the Mo-encapsulated Type 304L stainless steel was remarkably higher than those of the sintered Type 304L and Type 316L stainless steels. The corrosion inhibition mechanism of the Mo-encapsulated Type 304L stainless steel was discussed from three viewpoints: (1) passive film modification on the steel matrix, (2) cathodic protection of the steel matrix by the Mo core dissolution, and (3) corrosion inhibition by molybdate dissolved from the Mo-enriched particles, and the last one appeared to be the most likely.

Investigation of 2-ethoxy-4-(oxiran-2-ylmethyl)phenol as a potentially effective anti-corrosion agent for C38 steel

This study presents a comprehensive investigation into the corrosion inhibition efficacy of the compound, 2-ethoxy-4-(oxiran-2-ylmethyl) phenol (EP), on C38 steel surfaces exposed to a highly corrosive 1 M HCl environment. Through a unique integration of experimental techniques—Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization (PDP), Weight Loss (WL), Scanning Transmission Electron Microscopy coupled with X-ray Energy Dispersive Spectroscopy (STEM/XEDS)—and advanced theoretical methods, including Quantum Chemical Calculations (QCCs), Density Functional Theory (DFT), and Monte Carlo simulations (MCs), the study provides a deep and novel understanding of EP's corrosion inhibition mechanism. The findings reveal that EP acts as a mixed-type inhibitor, achieving a remarkable corrosion inhibition efficiency of approximately 92 % at 298 K by forming a protective layer on the steel surface. Notably, the adsorption of EP is characterized by both physisorption and chemisorption, adhering to the Langmuir isotherm model, a dual-mode mechanism that has been underexplored in similar compounds. The synergy between experimental data and theoretical simulations, particularly the use of DFT and MD simulations, elucidates the molecular interactions and adsorption behaviors that are critical to EP's effectiveness. This novel approach not only confirms EP's potential as a high-performance corrosion inhibitor but also contributes significant insights into the factors that govern corrosion inhibition, advancing the field's understanding of inhibitor design and application.

Chemoinformatics for corrosion science: Data-driven modeling of corrosion inhibition by organic molecules.

This paper reviews the application of machine learning to the inhibition of corrosion by organic molecules. The methodologies considered include quantitative structure-property relationships (QSPR) and related data-driven approaches. The characteristic features of their key components are considered as applied to corrosion inhibition, including datasets, response properties, molecular descriptors, machine learning methods, and structure-property models. It is shown that the most important factors determining their choice and application features are: (1) the small or very small size of datasets, (2) the mechanism of corrosion inhibition associated with the adsorption of inhibitor molecules on the metal surface, and (3) multifactorial conditioning and noisiness of response property. On this basis, the application of machine learning to the inhibition of corrosion of materials based on iron, aluminum, and magnesium is considered. The main trends in the development of QSPR and related data-driven modeling of corrosion inhibition are discussed, the shortcomings and common errors are considered, and the prospects for their further development are outlined.

Synthesis, structural characterization, thermal analysis and anticorrosion properties of novel AZO-based imidazo[1,2-a]pyridine derivatives: Experimental study and theoretical approaches

In this study, innovative AZO-based imidazo[1,2-a]pyridine derivatives were synthesized using simple and efficient synthetic approach enabling large-scale production. Thermal analysis highlights their suitability for potential applications requiring resistance to moderate temperatures. These compounds were investigated as corrosion inhibitors for MS in a 1 M HCl-medium. Corrosion inhibition studies, including weight loss, PotentioDynamic polarization and electrochemical impedance spectroscopy methods, revealed that AZOs exhibited maximum corrosion inhibition efficiencies reaching 96.13 % and 94.07 %, respectively, at a concentration of 10−3 M and a temperature of 298 K, with both compounds acting as mixed-type inhibitors. The study also delved into the influence of temperature and immersion time on inhibitory performance, revealing stable inhibition within the temperature range of 298–328 K. The calculated standard free energy of adsorption was −42.06 and −40.62 kJ/mol for AZO 1 and AZO 2, respectively, suggesting mixed-type adsorption, with adsorption behavior following the Langmuir isotherm. Morphological analysis through SEM and AFM, showed a reduction in surface roughness in the presence of the inhibitors, while water contact angle measurements indicated a significant increase in surface hydrophobicity. UV–visible and FT-IR analyses confirmed the interaction of AZOs with the MS surface, suggesting the formation of a protective layer composed of adsorbed AZO molecules. Furthermore, computational investigations employing DFT, Monte Carlo, and Molecular Dynamic simulation revealed the formation of coordinate bonds between the studied inhibitors and the metal surface, confirming adsorption on the metallic surface. These findings align well with experimental outcomes, and a possible corrosion inhibition mechanism process was discussed.

High temperature long-lasting corrosion inhibition mechanism of sodium dodecyldiphenyl ether disulfonate on ADC12 aluminum alloy in oxalic acid solution

The high temperature corrosion inhibition mechanism of sodium dodecyl diphenyl ether disulfonate (MADS) on ADC12 aluminum alloy in oxalic acid solution at 80 °C was investigated using electrochemical measurements, surface characterization and theoretical computations. The results manifested that MADS still had excellent performance in high-temperature oxalic acid solution, and was a highly efficient and long-lasting corrosion inhibitor with an optimal corrosion inhibition efficiency (ƞ) of 90.90 %. With increasing soaking time, the ƞ increased to 98.70 %. MADS molecule adsorbed on the aluminum alloy surface in an L-shaped walking scooter configuration through physicochemical adsorption to form a dense, thin and stable hydrophobic film, inhibiting the formation of aluminum oxalate and Al2O3, and protecting it from corrosion.

How does the integration of amino acids enhance the bonding ability of triazine-based inhibitors with iron surfaces: Insights from SCC-DFTB, COSMO-RS and molecular dynamics simulations

Theoretical investigations into the adsorption of molecules on metal surfaces play a pivotal role in the development of more efficient corrosion inhibitors. This study offers a novel approach by combining Density Functional Tight Binding (DFTB), Molecular Dynamics (MD) simulations, and conductor-like screening model for realistic solvation (COSMO-RS) calculations to comprehensively assess the interaction and diffusion properties of glycine (Gly), 2,2′-azanediyldiacetic acid (IDA), and 5-aminopentanoic acid (5-APA) with two 1,3,5-triazine (Tris) derivatives (Tris-Gly and Tris-IDA) for corrosion protection of carbon steel in acidic medium. The solvation properties of these molecules were evaluated alongside their interaction strength with the Fe(1 1 0) surface, considering both neutral and protonated forms. DFTB simulations revealed a clear trend in interaction energies, following the order: Tris-IDA > Tris-Gly > 5-APA > IDA > Gly. It ranges from −1.191 eV to −1.853 eV, with the highest stability observed for protonated Tris-IDA (−1.853 eV), while neutral Glycine exhibits the lowest interaction energy (−1.263 eV). While these theoretical results diverged slightly from experimental observations, with Tris-Gly outperforming Tris-IDA, this discrepancy was attributed to steric effects and solvent interactions. The DFTB results also indicated strong covalent interactions, particularly involving acetic groups, between the inhibitors’ orbitals and the iron’s 3d orbitals. MD simulations further demonstrated the impact of protonation on inhibitor mobility, with reduced diffusion coefficients due to enhanced electrostatic interactions and hydrogen bonding. COSMO-RS solvation analysis confirmed the strong hydrogen bonding capabilities of these molecules with water. Overall, this study elucidates the mechanisms of corrosion inhibition by integrating multiple simulation techniques, providing key molecular insights that can guide the design of more effective corrosion inhibitors. The findings emphasize the significance of electronic interactions and molecular structure in enhancing inhibitor performance, making this a valuable contribution to corrosion science.

Unlocking the power of Dryopteris filix mas extract: A green solution for corrosion inhibition in A210Gr carbon steel in acidified 3% wt. NaCl environment

This study investigates the corrosion inhibition effectiveness of Dryopteris filix-mas L. (DFM) extract for A210Gr carbon steel in a 3 % NaCl solution. The DFM ethanolic extract was successfully prepared and comprehensively characterized using a combination of spectroscopic and physicochemical techniques, including HPLC, FTIR, and NMR (1H and 13C). These analyses confirmed the presence of key phenolic compounds, with Quercetin-3-O-diglucoside (Q3ODG) being the major component, comprising 82.14 % peak area as identified by HPLC. The extract, obtained via an economical ethanol extraction method, exhibited a maximum inhibition efficiency up to 88 % at a concentration of 400 ppm, as determined through electrochemical impedance spectroscopy (EIS), open circuit potential (OCP), potentiodynamic polarization (PDP), and weight loss measurements. Temperature studies revealed a drop in efficiency to 70.14 % at 323 K, indicating a temperature-sensitive inhibition mechanism. Extended immersion times led to a slight decrease in efficiency due to partial desorption, though significant protection remained after 72 h. The primary corrosion inhibition mechanism was determined to be physisorption, following the Langmuir isotherm model, with a ΔGads0 value of − 24.02 kJ/mol, indicating a spontaneous adsorption process. Thermodynamic analysis revealed an increase in Ea from 22.11 kJ/mol (blank) to 56.61 kJ/mol (400 ppm), confirming the formation of a strong protective barrier. Surface characterization techniques, including FTIR, XRD, SEM, and AFM, further confirmed the presence of a protective film rich in polar organic compounds. Complementary Density Functional Theory (DFT) and Quantum Theory of Atoms in Molecules (QTAIM) studies provided detailed insights into the molecular interactions, highlighting the key role of hydrogen bonding and van der Waals forces in the adsorption of Q3ODG onto the steel surface. These findings underscore the potential of DFM extract as an effective and sustainable corrosion inhibitor, advancing the application of biocompounds in corrosion control and encouraging further exploration of their industrial applications and environmental benefits.

Synthesis, Characterization, Theoretical, and evaluation of Eco-Friendly benzimidazolylmethyl-pyrazole carboxylate Schiff Bases corrosion inhibitors for mild steel

In this study, benzimidazolylmethyl-pyrazole carboxylate derivatives were synthesized via a 1,3-dipolar cycloaddition reaction and characterized using IR, HRMS and NMR spectroscopy. Three derivatives, namely ethyl 5-((3-(cyclohex-1-en-1-yl)-2-oxo-2,3-dihydro-1H-benzo[d]imidazol-1-yl)methyl)-1-phenyl-1H-pyrazole-3-carboxylate (Ph-BPC), ethyl 5-((3-(cyclohex-1-en-1-yl)-2-oxo-2,3-dihydro- 1H-benzo[d]imidazol-1-yl)methyl)-1-(p-tolyl)-1H-pyrazole-3-carboxylate (CH3Ph-BPC), and ethyl 1-(4-chlorophenyl)-5-((3-(cyclohex-1-en-1-yl)-2-oxo-2,3-dihydro-1H-benzo[d]imidazol-1-yl)methyl)-1H-pyrazole-3-carboxylate (ClPh-BPC), were evaluated as corrosion inhibitors for mild steel (MS) in a 1 M HCl solution. Potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) measurements revealed high inhibition efficiencies of 98.5 %, 98.2 %, and 97.7 % for ClPh-BPC, Ph-BPC, and CH3Ph-BPC, respectively, at a concentration of 10-4 M. Scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD) analyses confirmed the formation of protective surface layers, significantly reducing corrosion rates. Thermodynamic analysis indicated that the adsorption of these inhibitors follows the Langmuir isotherm model with adsorption energies of −50.12 kJ/mol for ClPh-BPC, −50.52 kJ/mol for Ph-BPC, and −51.62 kJ/mol for CH3Ph-BPC, suggesting chemisorption. Computational studies, including Monte Carlo (MC), density functional theory (DFT), and molecular dynamics (MD) simulations, showed strong agreement with experimental results, further validating the adsorption behavior and corrosion inhibition mechanisms of these compounds.

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.

Insight into the corrosion inhibition performance of dimethyldiallylammonium chloride acrylamide copolymer for mild steel in acidic solution

Dimethyldiallylammonium chloride acrylamide (DADMAC-AAM) copolymer was firstly applied as a novel corrosion inhibitor for carbon steel in acidic solution. Electrochemical, theoretical and computational methods were performed to illustrate the corrosion inhibition mechanism of DADMAC-AAM. Results of electrochemical tests indicated that DADMAC-AAM effectively slowed down corrosion rate of mild steel in HCl solution as a mixed-type corrosion inhibitor. Its corrosion inhibition efficiency increased with dosage, and the maximum value reached about 92.44 % with adding 100 mg/L. In-situ scanning vibration electrode technique illustrated that the corrosion inhibition performance of DADMAC-AAM increased with immersion time. Metal surface was covered with a dense hydrophobic film due to the physical-chemical adsorption of DADMAC-AAM molecules, and the adsorption behavior obeyed to the Langmuir adsorption isothermal model. Theoretical calculations were carried out to explain the corrosion inhibition mechanism, and the increase of active energy indicated that the strong inhibitive action of DADMAC-AAM molecule could be due to the increase of activation energy barrier of corrosion reaction. Results obtained from computational simulations proved that DMDMAC-AAM molecules adsorbed on metal surface through interactions between N or O and Fe atoms. This adsorption film could retard the invasion of corrosive species, thus protecting metal from corrosion.

Insight into the corrosion inhibition mechanism of mild steel St1 in 2 M H2SO4 electrolyte by azithromycin

Mild steel is essential in modern industry due to its favorable mechanical properties and economic availability. However, its high susceptibility to corrosion, especially in acidic environments, poses a significant challenge, reducing service life, increasing operating costs, and raising the risk of failures. This study investigates the corrosion inhibition mechanism of mild steel St1 in a 2 M H2SO4 solution at various temperatures using the broad-spectrum antibiotic azithromycin (AZM). Experimental results indicate that AZM presence increases the polarization resistance of mild steel in the acidic solution. AZM acts as a mixed-type inhibitor, influencing the kinetics of both cathodic and anodic processes. The introduction of 200 mM AZM leads to an increase in the polarization resistance of the steel electrode in 2 M H2SO4 by up to 2.4 times. The inhibition mechanism involves forming a protective layer of protonated AZM forms on the negatively charged Fe surface. These protonated forms can also adsorb on cathodic areas, competing with hydronium ions (H3O+) and thereby inhibiting hydrogen evolution processes. The protective effect of AZM diminishes with increasing temperature of the corrosive environment, as confirmed by Monte Carlo simulations showing decreased adsorption energies for AZM and its protonated forms at higher temperatures. An assessment of the protective effect of 200 mM AZM showed that an increase in the temperature of the corrosive environment from 293 to 333 K leads to a decrease in the protective effect by almost 5.6 times. Quantum chemical calculations determined the reactivity of AZM and its protonated forms, identifying the molecular groups involved in the adsorption mechanism.

Corrosion inhibitors in H2O2 system slurry for Ru based barrier layer Cu interconnect chemical mechanical polishing and optimization

Ruthenium (Ru) has the advantages of low resistivity, high thermal stability, and good adhesion and wettability, making it an important solution for breaking through the 14 nm process as a new barrier layer material for multilayer copper interconnect. The purpose of copper (Cu) interconnect Ru-based barrier layer chemical mechanical polishing (CMP) is to obtain a highly flat surface, which not only includes the ideal Ru removal rate and selectivity of the Cu/Ru removal rate, but also inhibition of Cu corrosion. In this article, the corrosion inhibition mechanism of environmentally friendly and highly water-soluble inhibitor 5-methylthio-1 H-tetrazole (MTT) on Cu was studied. The inhibitory effect of MTT on Cu was analyzed through static etching rate testing, electrochemical experiments, and surface characterization. A systematic test was conducted on the planarization performance of the optimized polishing slurry. The corrosion inhibition mechanism of MTT on Cu was revealed through quantum chemical calculations and XPS testing. The experimental results show that the corrosion inhibitor MTT can effectively improve the surface quality of Cu. Quantum chemical calculations and experimental results indicate that MTT can be adsorbed on the surface of Cu through both physical and chemical methods, forming a dense passivation film, thereby inhibiting the corrosion of Cu. The optimized ratio of Ru-based barrier layer CMP polishing slurry was 5 wt% SiO2, 0.15 wt% H2O2, 20 mM ethylenediamine (EDA), 5 mM K4Fe(CN)6, and 2000 ppm MTT, resulted in the Cu/Ru removal rate selectivity of 1:1.18 and the Cu/Ru corrosion potential difference of 3 mV. The average correction values for dishing and erosion on the test pattern wafer of the Ru barrier layer were 355 Å and 280 Å, respectively. The results of this study indicate that MTT is an effective copper corrosion inhibitor in alkaline H2O2-based polishing slurry, providing meaningful references for Ru-based barrier layer copper interconnect CMP.

Comprehensive assessment of the corrosion inhibition properties of quinazoline derivatives on mild steel in 1.0 M HCl solution: An electrochemical, surface analysis, and computational study

The efficacy of two compounds, namely 12-(4-chlorophenyl)-3,3-dimethyl-3,4,5,12-tetrahydrobenzo[4,5] imidazo[2,1-b]quinazolin-1(2H)-one (Q-Cl) and 3,3-dimethyl-12-phenyl-3,4,5,12-tetrahydrobenzo[4,5]imidazo[2,1-b]quinazolin-1(2H)-one (Q-H), in inhibiting corrosion on mild steel in 1.0 M hydrochloric acid was evaluated. Surface analytical techniques and electrochemical procedures were employed for examination. The results demonstrated that both Q-Cl and Q-H significantly inhibit corrosion. Specifically, Q-Cl achieved an inhibition efficiency of 85.2 % at a concentration of 10⁻³ M, while Q-H exhibited a higher inhibition efficiency of 91.5 %. Electrochemical investigations suggested that both Q-Cl and Q-H acted as inhibitors of mixed-type corrosion. These chemicals efficiently prevented metal corrosion through adsorption, conforming to Langmuir's adsorption isotherm model. The adsorption mechanism of corrosion inhibition was further supported by surface investigations and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX). Additionally, Density Functional Theory (DFT) and other computational approaches were employed to study the anti-corrosion mechanism of Q-Cl and Q-H. These simulations yielded theoretical results that aligned with the preceding experimental findings.

Lycium barbarum extract as an environmentally friendly corrosion inhibitor for AISI 52100 bearing steel in hydrochloric acid medium

This study reports the use of Lycium barbarum extract (LBE), a green and environmentally friendly additive, to inhibit the corrosion of AISI 52100 bearing steel in 1 M hydrochloric acid (HCl) solutions. Corrosion inhibition was experimentally investigated via the weight loss method and electrochemical analyses. The surface morphologies were evaluated by scanning electron microscopy (SEM), and the chemical compositions were analyzed via energy-dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR). The experimental electrochemical and weight loss results demonstrated that LBE has excellent inhibitory properties, with the highest inhibition efficiencies of 92.68 % and 92.31 % when the concentration is 500 ppm, for steel immersed in HCl solutions. Surface coverage studies revealed that the data for the adsorption of LBE on steel were consistent with the Langmuir isotherm. The initial process was investigated via polarization analysis, and the LBE adsorption process was found to be a hybrid of physical and chemical adsorption. To investigate the effectiveness of LBE in preventing corrosion, the corrosion inhibition mechanism was analyzed via a wettability study, high performance liquid chromatography (HPLC) measurements and theoretical quantum chemical calculations. The results indicated that Ara, Rha, Man and Glu played significant effect on the protection of bearing steel in 1 M HCl solution.

Experimental and Computational Investigation of Salicylhydroxamic Acid as a Corrosion Inhibitor for Copper in Alkaline Solutions

Inhibitors, as indispensable components in chemical mechanical polishing (CMP) slurries, have a significant impact on inhibiting copper (Cu) corrosion and enhancing post-polishing surface quality. However, one of the major challenges in CMP lies in unraveling the microscopic corrosion inhibition mechanism of Cu. This work focuses on investigating the impact of an inhibitor, salicylhydroxamic acid (SHA), on the static etching rate (SER), electrochemical parameters, and surface morphology of Cu. The experimental findings demonstrate that SHA significantly decreases the SER and corrosion current density of Cu, while notably improving the Cu surface quality. The corrosion inhibition mechanisms of SHA on Cu are revealed through adsorption isotherm models, contact angle analysis, electrochemical impedance spectroscopy, and computational chemistry method. The benzene ring, oxime group, and O1 atom of SHA exhibit significant chemical reactivity, facilitating the preferential adsorption of SHA on Cu in a parallel orientation, thereby forming a hydrophobic protective film on the Cu surface. This process hinders the interaction between corrosive solutions and Cu, therefore SHA exhibits excellent corrosion inhibition performance on Cu. These findings hold great importance in gaining a deeper comprehension of the corrosion inhibition process of Cu, and provide guidance for designing more efficient inhibitors.