Corrosion Retardation Research Articles

One-pot synthesis of N'-(thiophen-2-ylmethylene)isonicotinohydrazide Schiff-base as a corrosion inhibitor for C-steel in 1 M HCl: Theoretical, electrochemical, adsorption and spectroscopic inspections

Although carbon steel (CS) is an essential component utilized in many industries, it regrettably corrodes when exposed to acidic conditions. Schiff bases have recently become more concerned with the corrosion prevention of CS. Hydrazides and the related compounds shown to be effective inhibitors of CS corrosion in acids. These compounds are commonly employed as origins or intermediates to several key molecules in the synthesis of organic compounds, and they are highly sought after due to their wide range of biological and therapeutic applications. They have anti-bacterial, anti-malarial, anti-fungal, and anticancer properties, as well as corrosion protection. Hence, the inhibitory effectiveness of a new synthesized (E)-N'-(thiophen-2-ylmethylene) isonicotinohydrazide (TMNH) Schiff-base for the corrosion of CS in 1 M HCl was explored. The structure of TMNH was validated by FT-IR and 1H NMR spectroscopy. A number of chemical, spectral, and electrochemical techniques such as potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and mass loss (ML) have been used to evaluate its anticorrosion power. PDP measurements showed that it is a mixed-type inhibitor. In addition, EIS measurements showed that Rct increased sharply from 37 without the corrosion inhibitor to 589 Ω cm-2 in the presence of 1 mM TMNH and from PDP scans, the corresponding icorr decreased dramatically from 0.6158 to 0.0314 μA cm-2. ML tests have proven their effectiveness, achieving an inhibitory efficiency of 95.3 %. Adsorption studies were also conducted to determine the nature of the corrosion retardation mechanism. The TMNH inhibitor was spontaneously chemically/physically adsorbed onto the CS surface following the Langmuir isotherm. Statistical calculations were also applied to verify the accuracy of the experimental results. The Monte Carlo model showed that the inhibitory molecules adsorbed flat on only one side, increasing the chances of adsorption.

Self-healing epoxy coatings via microencapsulation of aromatic diisocyanate in lignin stabilized Pickering emulsions

Isocyanate-filled microcapsules are gaining increased attention for their role in developing self-healing materials, thereby reducing maintenance costs and increasing polymer durability. Nevertheless, microencapsulating highly reactive -NCO groups remains a challenging task in the literature. Likewise, considerable efforts have been directed towards developing polymers from renewable and biobased sources, which could also be applied to microcapsule synthesis. In this work, lignin, an abundant biopolymer, was used as a solid stabilizer for oil-in-water (O/W) interfaces, enabling the encapsulation of highly reactive isocyanate. Hybrid polyurethane/polyurea microcapsules containing reactive methylenediphenyl diisocyanate (MDI) were obtained via optimized O/W Pickering emulsions using lignin for system stabilization. This optimized process facilitated shell formation via the reaction of diisocyanate with lignin and water, eliminating the need for additional chain extenders. Scanning electron microscopy revealed the formation of spherical and rough microcapsules, while infrared spectroscopy confirmed the presence of residual free -NCO groups, indicating effective encapsulation of MDI. Additionally, a core -NCO concentration of 11 wt% was confirmed by titration. The microcapsules were further assessed as components in self-healing epoxy coatings. Their incorporation resulted in the retardation of corrosion on a low carbon steel panel after 72 h of submersion in a saline solution. Electrochemical impedance spectroscopy (EIS) confirmed a significant increase of approximated 620% in impedance modulus after 83 days of immersion in a 3.5 wt% NaCl solution, compared to the neat epoxy coating. These findings suggest a promising technological application of this material for the advancement of self-healing epoxy-based coatings and composites.

Synthesis of 5-benzyl-5-((5-nitropyridin-3yl)methyl)-1,3,5-dithiazinan-5-ium through one-pot reactions, characterization and study as a corrosion retardant in high salinity oil fields.

This study included the preparation of a new heterocyclic compound namely 5-benzyl-5-((5-nitropyridin-3-yl) methyl)-1,3,5-dithiazinan-5-ium (BNPD) by a simple powerful method and an environmentally acceptable. The BNPD compound contains O, N, and S heteroatoms that have been inserted into the chemical structure by one step consisting of several transformations. The BNPD structure has been characterized using several techniques like FT-IR, 1H-NMR, 13C-NMR, and G-C mass. The prepared molecule has been studied as an inhibitor of carbon steel corrosion (N-80), which is generally used in oil fields. The BNPD effectiveness has been studied as an anti-corrosive material in saline water that accompanies the extraction of crude oil. Saline water contains dissolved solids estimated at 239581mg/l, conductivity 254.23 ms/cm, and pH 6.1. The retardant has been evaluated by electrochemical impedance spectroscopy technique (EIS), potentiodynamic polarization technique (PP), scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM/EDX), and weight loss method (WL) at 308K(±1). It was noted that inhibition efficiency increases with increasing BNPD concentration. The results of potentiodynamic polarization showed that the studied inhibitor molecules act as a mixed-type inhibitor, while the results of weight loss showed that these molecules adsorbed on the carbon steel surface through physical and chemical adsorption simultaneously. The results of the SEM/EDX indicated that slight corrosion occurred at the inhibitor was added, where the EDX spectrum of N-80 at 80 mg.dm-3 of inhibitor was noticed approximately similar to the polished carbon steel spectrum. Furthermore, the electronic and physic-chemical characteristics of BNPD have been calculated like EHOMO, ELUMO, energy gap, total energy, lipophilicity coefficient, molecule surface area, molecular volume, molecular polarizability, molar refractivity, dipole moment, solvation energy, theoretical inhibition efficiency, and electrostatic potential surfaces. The BNPD compound has shown wonderful results in corrosion inhibiting, where its efficiency optimum reached 91.14%, 93.60%, and 93.46% for WL, EIS, and PP techniques, respectively. Either theoretical efficiency reached 90.25%.

A multi-phase multi-species phase field model for non-uniform corrosion and chloride removal in concrete

Electrochemical chloride removal (ECR) facilitates the retardation of rebar corrosion and the extension of service life. In this paper, we present a multi-phase multi-species phase field model at the mesoscale to investigate the time-dependent processes of rebar corrosion, electrochemical chloride removal, and re-corrosion. This model captures multi-species ion transport, electrochemical reactions, electrochemical chloride removal, concrete cracking and crack-induced diffusivity variation in the processes of rebar corrosion. This model was verified using two experiments from the literature. Parametric studies were conducted to observe the effects of current density, treatment time and concrete cover thickness on chloride concentration and crack width during the corrosion initiation and corrosion propagation stages. The chloride transport and crack evolution processes in ECR-treated concrete were highlighted. Two indexes are proposed for the chloride-induced corrosion resistance of concrete in the corrosion initiation and corrosion propagation stages.

Polybenzopyrrole/nano-alumina composite blend with zirconium silicate reinforced epoxy as protective coating to subside corrosion of carbon steel within a dilute NaCl solution

The present work inspects the corrosion retardation of carbon steel by zirconium silicate reinforced epoxy blended with fabricated (PB/AN) polybenzopyrrole/nano-alumina composite, termed as PB/AN@ZE coating. Nano-alumina (AN), polymer polybenzopyrrole (PB), and polymer nanocomposite (PB/AN) were conveniently synthesized and their structural, thermal and morphological information were confirmed through Fourier transform infrared spectroscopy, X-ray diffraction, Thermogravimetric analysis, Atomic Force Microscopy and Field Emission Scanning Electron Microscopy. The molecular dynamics computation data evidence that the designed composite PB/AN is highly stable and found to have the interaction energy of 67.63 eV. Anti-wettability behaviour of the formulated coating was examined using Contact-angle Goniometer. The corrosion-resistant behaviour with different weight% loading of PB/AN in the zirconium silicate reinforced epoxy coating on low-carbon steel was examined in 3.5 % NaCl by using EIS or Electrochemical Impedance Spectroscopy and PDP or Potentiodynamic polarisation studies. The EIS and PDP results of 0.25% PB/AN@ZE coating indicated the excellent barrier to control the corrosion kinetics with high protection efficiency of 97.14 % even after 24 days immersion in NaCl solution and damage induced coating (kept immersed for 24 h in NaCl) was evidenced with a high impedance value of 1.48 × 109 Ω.cm2.

An Outline of Employing Metals and Alloys in Corrosive Settings with Ecologically Acceptable Corrosion Inhibitors

Researchers have just discovered an alternative to synthetic corrosion inhibitors, which are hazardous and terrible for the ecosystem, to prevent rusting in the environment. A metal corrodes when it is subjected to corrosive media (acid, base, or saline) and they deteriorate, leading to failure. The most straightforward and affordable corrosion protection and prevention technique in acidic environments has been proven to be corrosion inhibitors. On industrial surfaces, pieces of machinery, or vessels, these inhibitors slow the rate of corrosion, preventing the monetary losses brought on by metallic corrosion. Recently, attention has been directed to developing ecologically appropriate corrosion retardation methods because inorganic and organic inhibitors are harmful and expensive. Recent studies have focused on green mild steel (MS) corrosion inhibitors that mimic industrial processes in acidic conditions. This presentation briefly covers the many types of corrosion, the corrosion process and the most recent studies on using natural plant extracts as corrosion inhibitors. Since they are safe and cost-effective, green corrosion inhibitors are a new trend in preventing corrosion. These inhibitors are produced from various plant parts, and inhibition efficiency (IE) also depends on them. To ascertain the IE of the corrosion inhibitor, some experiments, including computational studies (quantum calculations and MD simulations), electrochemical measurements (electrochemical impedance (EIS) and potentio-dynamic polarization), surface morphology atomic force microscopy (AFM), scanning electron microscopy (SEM)/energy-dispersive X-ray analysis (EDX) and UV–visible spectroscopy are carried out. It has been demonstrated that the IE is maximum for green corrosion inhibitors compared to synthetic inhibitors. This paper provides an overview of the properties, mechanism of corrosion inhibitors, nature of green corrosion inhibitors and their IE obtained by performing tests. This review article discussion shows that reinforcement with plant extract performs well in aggressive environments, which is evident from electrochemical studies and surface analysis when compared to reinforcement with inhibitors.

Investigation of Vitamin B12 as a corrosion inhibitor for mild steel in HCl solution through gravimetric and electrochemical studies

Now a days green corrosion inhibitors are highly in demand to mitigate corrosion of metal and alloys due to their non-toxicity as well as the absence of heavy metal and toxic compounds in comparison to the organic corrosion inhibitors. Since in the past research conducted on vitamin B12 as a corrosion inhibitor, the study of thermodynamic and kinetic parameters was lacking, the present work is focussed on the temperature dependence of corrosion on Vit B12(Vitamin B12) for the mild steel surface which is an influencing parameter in the present day to day industrial problems. There is a desirable need for efficient inhibitors which work well in high temperatures too. So the present study consciously restricts itself to Vit B12, a naturally occurring corrosion inhibitor. VitB12 is a water-soluble vitamin and also called cobalamin. It is an ecofriendly organometallic compound, has many adsorption sites, and is thus a promising candidate for corrosion retardation. The Potentio-dynamic Polarisation and Electrochemical Impedance Spectroscopy (EIS) are the two techniques that have been used in the analysis of the corrosion inhibition efficiency of Vit B12. It has been observed that the addition of inhibitor Vit B12, shows an enhancement in the Rct (charge transfer resistance) and a decrease in the capacitance layer Cdl value, which indicates the formation of a protective layer over the mild steel surface. The study of thermodynamic and kinetic parameters of the inhibitor adsorption over the mild steel was performed through temperature study. The surface morphology in the absence and presence of Vit B12 on the mild steel was analyzed by FE-SEM where the smooth surface is visible in the presence of inhibitor which shows the protective behavior of Vit B12.

Rosemary extract inhibitive behavior against mild steel corrosion in tempered 1 M HCl media

Recent industrial issues are quite noteworthy for researchers that encourage them to introduce unique approaches to solve them. Among all, corrosion disasters were nominated as the most important ones. Although various routes were introduced for substantial corrosion limitation, inhibits were highly appreciated for worldwide industrial processes. Although the application of inhibitors can substantially prevent the corrosion of metallic substrates, their usage is not far from the limitations. Nowadays, due to the environmental hazards and toxicity of traditional inhibitors, green inhibitors are now replaced. Regarding the special position of plant extracts in the family of green inhibitors, attention should be paid to special features such as renewability and easy access. Undoubtedly, these capabilities have made plant extracts a practical class among all other types. Herein, the Rosemary extract is considered a golden candidate that can be employed as a green corrosion inhibitor in HCl media. The chemistry of Rosemary extract was estimated by Fourier-transform infrared (FT-IR), and Ultraviolet-visible (UV-Vis) spectroscopies. Afterward, the anti-corrosion performance of this inhibitor has been evaluated with electrochemical (potentiodynamic polarization and Electrochemical impedance spectroscopy (EIS)) and weight-loss tests. This study did not neglect the surface studies and the morphology of the surfaces was observed by FE-SEM and AFM techniques. Eventually, the adsorption mechanism has been predicted by thermodynamic studies and adsorption isotherms. Electrochemical outcomes demonstrated that mixed-type inhibition is responsible for 92% corrosion retardation during 6 h steel exposure to 1 M HCl media. The weight-loss studies also had a high convergence with the electrochemical studies and with a slight negligible difference, 800 ppm of rosemary extract prevented 87% of steel corrosion.

Kinetic and thermodynamic evaluation of azithromycin as a green corrosion inhibitor during acid cleaning process of mild steel using an experimental and theoretical approach

Data from experiments and molecular computation were used to evaluate azithromycin as a safe and innocuous corrosion retardant for mild steel in acidic environments. Hydrogen evolution experiments were conducted between 303 and 333 K with and without azithromycin in hydrochloric acid solution. SEM photos and the results of hydrogen evolution demonstrate that azithromycin suppresses steel corrosion in an acidic environment. The inhibition efficiency (IE%) of azithromycin increases with the rise in concentration and the drop in temperature. The maximum IE% (81.36%) was obtained at 800 mg/L of azithromycin at 303 K. The corrosion reaction rates could be described with a first-order rate law. The range of thermodynamic parameters obtained from 303 K to 333 K for entropy (−181.2 to −91.9 J/mol), enthalpy (18.6 to 50.1 kJ/mol), and activation energy (21.2 to 52.7 kJ/mol) indicate the corrosion is spontaneous and endothermic. The results of the experiment agreed with the Langmuir model for adsorption, and physisorption is postulated for the adsorption of azithromycin on mild steel based on the ΔG values (−12.0 to −2.8 kJ/mol) which were below −20 kJ/mol. According to computational details, oxygen hetero atoms with relatively very large Mulliken charges are the most susceptible active locations for adsorption of Azithromycin on the metal surface.

Application of green active bio-molecules from the aquatic extract of Mint leaves for steel corrosion control in hydrochloric acid (1M) solution: Surface, electrochemical, and theoretical explorations

Due to environmental awarenesses and strict restrictions, industries are forced to bring their processes closer to the considered eco-friendly standards. Without a doubt, corrosion is the most obvious problem in industries and inhibitors are among the most applicable materials for metals' corrosion retardation. For this reason, extensive studies have been conducted in the field of green corrosion inhibitors in recent years. The present work concentrated on the evaluation of the bio-molecules from Mint leaves extract on the steel corrosion mitigation in HCl solution. The Mint extract (ME) structures were investigated by FTIR, UV-Vis, and Raman spectroscopies. It was shown by a polarization experiment that Mint extract at 800 ppm caused the current density (icorr) reduction from 1.03 mA/cm2 (for the blank sample) to 0.11 mA/cm2 which was aided by a mixed inhibition (cathodic – anodic) mechanism. The EIS results illustrated that at the optimum condition around 91 % inhibition degree was reached after introducing 800 ppm Mint extract. The weight loss investigations, however, affirmed that a 92 % efficiency was achievable at 25 °C, which was mitigated to 89 % at 55 °C. Eventually, the thermodynamic and adsorption isotherm records represented that Mint extract molecules mono-layer was constructed by utilizing the exothermic interactions. Via the MD and DFT simulations, the interfacial interactions and corrosion inhibitors' adsorption mechanism over the steel surface was exhibited.

Study of synergy of monoethanolamine and urea on copper corrosion inhibition in alkaline solution

• Cu corrosion in TMAH-containing solution is investigated. • MEA and urea are used as corrosion inhibitors to retard the Cu corrosion. • The synergy of MEA and urea on Cu corrosion inhibition is concentration ratio dependent. • Cu corrosion becomes more serious at low concentration ratio of MEA to urea. • Cu corrosion is effectively retarded at high concentration ratio of MEA to urea. Tetramethylammonium hydroxide (TMAH) is an important constituent used in the post cleaning process of chemical mechanical planarization and lithography; however, its corrosive property causes damage to the Cu metallization. Addition of corrosion inhibitor in the cleaning solution is a promising method to protect Cu. In this study, two corrosion inhibitors, monoethanolamine (MEA) and urea, are used to investigate their synergy on the Cu corrosion protection. Electrochemical and four-point probe methods are adopted to analyze the corrosion behaviors of Cu. Microstructural characterizations of Cu are performed using scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. X-ray photoelectron spectroscopy is used to realize the adsorption behaviors of inhibitors on the Cu surface. The results of corrosion current ( I corr ) and charge transfer resistance ( R ct ) indicate that addition of MEA and urea at an identical concentration does not produce a typical synergistic effect on the Cu corrosion protection due to mutual interference of two inhibitors. An increase of the MEA concentration overcomes the mutual interference, giving rise to a reduction of I corr and an increase of R ct . The effective retardation of the Cu corrosion is attributed to the sufficiency of inhibitors which can construct a dense protection layer on the Cu surface.

Structural and electronic impacts on corrosion inhibition activity of novel heterocyclic carboxamides derivatives on mild steel in 1 M HCl environment: Experimental and theoretical approaches

To study the corrosion mitigation on mild steel (MS) in 1 M HCl, the carboxamide derivatives namely: N–(1–benzyl piperidin–4–yl)pyridine–4–carboxamide (N–BPPC), N–(4–(pyridin–4–ylmethyl) phenyl)pyridine–4–carboxamide (N–PMPPC), (4–methylpiperazin–1–yl)pyrazin–2–yl) methanone (4–MPPM) were synthesized and characterized by spectroscopy techniques like FT-IR, LC-MS, and 1H &13C NMR. Experimental techniques like the weight-loss method, potentiodynamic, electrochemical impedance studies, and surface analysis were performed at 303 K. Their anti-corrosion efficiency was proportional to their concentration. Electrochemical techniques revealed that they acted as mixed-type inhibitors and proceeded via single charge transfer at the metal–electrolyte interface. Strong adsorption of carboxamide derivatives on mild steel (MS) was supported by surface morphology studies and obeyed the Langmuir model of the isotherm. The thermodynamic and activation parameters were measured to study the temperature effect, revealing that physicochemical adsorption took place. Anti-corrosion efficiencies were decreased with temperature rise. DFT and molecular dynamics studies have been utilized in their neutral and protonated form of inhibitors in the aqueous phase to study inhibitors’ structural and electronic impacts on the corrosion process. The optimized structure and spatial configuration exposed the influence of the molecule's alignment with the metal plane on corrosion mitigation. The molecules' bulk and local reactivity parameters show that the electron density of atoms of molecules coordinates with the metal surface. Finally, the order of corrosion retardation effect was found to be 4–MPPM > N–BPPC > N–PMPPC from experimental and theoretical studies.

A silicate-loaded MgAl LDH self-healing coating on biomedical Mg alloys for corrosion retardation and cytocompatibility enhancement

Clinical application of magnesium (Mg) alloys such as bone fracture fixation is hindered by the fast degradation rate under physiological conditions. In this work, a magnesium‑aluminum layered double hydroxide coating intercalated with silicate (LDH-SiO3) is fabricated on the anodized AZ31B Mg alloy by a hydrothermal technique and anion exchange process to tailor the corrosion rate and cytocompatibility. The LDH-SiO3 coating comprising a porous outer layer and compact inner layer adheres strongly to the anodized Mg alloy substrate. Electrochemical tests reveal that the LDH-SiO3 coating reduces the corrosion current density by 266 times to 0.8 ± 0.1 μA cm−2 in addition to yielding a large charge transfer resistance of 4.98 × 104 Ω cm2 in the simulated body fluid (SBF), revealing decreased corrosion because of inhibition of diffusion of aggressive ions through the compact and adherent inner LDH layer on the Mg alloy substrate. Immersion tests in SBF for 360 h reveal that the LDH-SiO3 coating mitigates corrosion propagation, Mg release, hydrogen evolution, and pH variation, indicating the notable long-term protection ability resulting from the self-healing LDH-SiO3 coating after localized corrosion occurs on the Mg alloy substrate. The self-healing mechanism mainly stems from SiO32− released from the LDH coating in conjunction with Mg leaching during natural degradation, resulting in the formation of Mg silicate precipitate that covers the corroded areas. Biologically, the LDH-SiO3 coating enhances attachment and proliferation of MC3T3-E1 pre-osteoblasts suggesting good cytocompatibility stemming from the favorable outcome including inhibited Mg leaching and alkalization as a result of the LDH-SiO3 coating. The self-healing LDH-SiO3 coating is very promising in expanding the clinical application of Mg-based implants by offering a viable approach to control corrosion and improve cytocompatibility.

Sodium alginate coating on biodegradable high-purity magnesium with a hydroxide/silane transition layer for corrosion retardation

Fast degradation of magnesium (Mg) and its alloys in the physiological environment has impeded their clinical use as temporary implants. To control degradation of Mg in the physiological environment, a sodium alginate coating is fabricated on alkalinized high-purity Mg with a silane transition layer by spin coating. The surface morphology and composition are investigated by scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction, and Fourier transform infrared spectroscopy. Electrochemical and immersion tests are performed in the simulated body fluid (SBF) at 37 °C. The composite coating with a thickness of 10.3 µm is uniform and adheres well to the Mg substrate. Compared to the bare substrate, the corrosion current density of the sample with the composite coating decreases from 130.9 ± 6.2–1.3 ± 0.3 μA cm−2 and the charge transfer resistance increases by 190 times. The average degradation rate in SBF drops to 0.80 ± 0.26 mm year−1 from 3.47 ± 0.25 mm year−1 of the pristine Mg substrate and the composite coating is demonstrated to impede corrosion of the Mg substrate after immersion in SBF for 14 days. The excellent protection rendered by the composite coating is ascribed to the effective barrier effects of the dense and adhering sodium alginate coating and blocking effect of chelate compounds of sodium alginate and Mg ions formed during the corrosion process.

Detailed experimental investigation of the highly active corrosion inhibitive green molecules based on zinc cations/Nepeta Pogonosperma extract and toward the corrosion mitigation of mild steel in the saline solution

This work has been focused on the synergistic corrosion retardation performance (CRP) of the Nepeta pogonosperma leaves from the Lamiaceae family, which is locally called Larzeh (LA), and zinc cations (Zn2+) over the mild steel plates (MSPs) in the 3.5 wt% sodium chloride (NaCl) solution (3.5%-SCS). Different concentrations of the LA extract and Zn2+ were dissolved in the saline solutions to prepare the solution systems. The electrochemical evaluation of MSPs submerged in the solution systems was performed using EIS and PP tests. Among various ratios of LA:Zn, the 300:700 ppm LA:Zn solution illustrated the highest CRP (119.3 kΩ cm2) and efficiency (93.7%) after 12 h and was selected as the optimal solution, while the CRP values of the blank, 700:300, and 500:500 ppm LA:Zn were 1.59, 57.1, and 38.4 kΩ cm2, respectively. In the presence of 700:300, 500:500, and 300:700 ppm LA:Zn, Icorr decreased from 3.78 μA cm−2 for the blank solution to 0.372, 0.345, and 0.236 μA cm−2, respectively. WCA results proved that a more hydrophobic layer (≈55°) was formed on the MSP with 300:700 ppm LA:Zn compared to those with 700:300 (≈33°) and 500:500 (≈24°) ppm LA:Zn. The surface characterization of MSPs submerged in 300:700 ppm LA:Zn solution was carried out using FT-IR, Raman, and GIXRD analyses. Surface characterization results proved the construction of a thicker multilayer zinc-centered organic inhibitive layer by the 300:700 ppm LA:Zn extract over the MSP surface compared to other MSPs with maximum amounts of O (7.85 wt%), C (6.55 wt%), N (1.78 wt%), and Zn (20.57 wt%) elements.

Investigation of inhibitive performance of Betahistine dihydrochloride on mild steel in 1 M HCl solution

This study evaluated the corrosion retardation of mild steel with the use of Betahistine dihydrochloride drug as a sustainable inhibitor in HCl solution and various techniques like weight loss measurements, electrochemical analysis was used to understand the inhibition process. The thermodynamic and adsorption parameters were calculated and discussed on the inhibition behaviour. The corrosion inhibition (% IE) gave a sharp rise with the increased concentration of the Betahistine dihydrochloride drug and reduced efficiency was observed with increased temperature and increased immersion time. Approximately 96% corrosion inhibition efficiency was attained with optimized conditions of 1500 ppm of Betahistine dihydrochloride, 2 h, 1 M HCl at 298 K temperature. Inhibitor adsorption to mild steel abided by the Langmuir adsorption isotherm. Electrochemical impedance spectroscopy revealed the reduction in the value of constant phase element, dip in the values of double-layer capacitance and increase in the charge transfer resistance with increased concentration of Betahistine dihydrochloride drug. Furthermore, potentiodynamic polarization experiments substantiated the mixed type of behaviour. The techniques like scanning electron microscopy, atomic force microscopy, along with ultraviolet–visible spectroscopy, fourier transform infrared spectroscopy, were employed for surface morphology and theoretical models like quantum chemical and molecular dynamics simulations authenticated the experimental observation.

Rational design of a novel multi-functional carbon-based nano-carrier based on multi-walled-CNT-oxide/polydopamine/chitosan for epoxy composite with robust pH-sensitive active anti-corrosion properties

A novel nano-carrier was designed by modifying the MWCNT surface by mussel-inspired polydopamine (PDA), chitosan (CH), and zinc cations. The results of the Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Raman, field emission scanning electron microscope (FE-SEM), energy dispersive X-ray analysis (EDX), and ultraviolet–visible (UV–vis) spectroscopy affirm the favored adsorption of the PDA, CH, and Zn (II) on the oxidized-MWCNT (OMWCNT) surface. The interactions of PDA, CH, and OMWCNT were theoretically evaluated by density functional theory (DFT-D) methodology. The dual active-barrier potency of the nanocomposites was evaluated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDS), and salt spray assessments. The remarkable enhancement of the total resistance (Rt) of the scratched epoxy coatings after introducing the OMWCNT-PDA-CH-Zn nanostructures (up to 3.6 times) indicates the simultaneous controlled release of the PDA, CH, and Zn(II) from the OMWCNT framework at the damaged area and their active corrosion protection (ACP) ability. The formation of a protective layer of the released inhibitors within the scratched zone was confirmed by FE-SEM/EDX analysis. The inclusion of OMWCNT-PDA-CH-Zn nanocomposite into the epoxy coating endowed the outstanding barrier capability and provided stable corrosion retardation for almost 9 weeks.

Experimental and theoretical analysis of baclofen as a potential corrosion inhibitor for mild steel surface in HCl medium

The effect of Baclofen on the retardation of mild steel corrosion was examined by employing the weight loss, electrochemical techniques and theoretical calculations. Investigations depicted the increased inhibition efficiency with the increased amount of Baclofen as a corrosion inhibitor and maximum inhibition efficiency was obtained ∼97% at the concentration of 2000 ppm of Baclofen. Potentiodynamic polarization study showed that Baclofen as an inhibitor controlled both the anodic and cathodic reactions but with cathodic predominance. Electrochemical analysis showed a clear decrease in the values of double layer capacitance. Adsorption of Baclofen on the surface of mild steel followed Langmuir adsorption isotherm. Experimental results were validated with the help of quantum chemical, molecular dynamic simulation, and surface morphological study.

Corrosion inhibition studies on mild steel in HCl by a newly synthesized benzil monohydrazone based Schiff base

The corrosion inhibition effect of newly formulated Schiff base 2-((E)-((E)-2-hydrazone-1, 2-diphenylethylidene) amino phenol) (HDAP) ligand L derived from Benzil monohydrazone and 2-Aminophenol on mild steel in 1 ​M HCl was examined. Electrochemical (Tafel and EIS) and mass loss techniques were employed to evaluate its corrosion protection efficiency. The inhibition efficiency (η %) was elevated with raise in concentration of compound L.Maximum inhibition efficiency of 94.18% was obtained at 0.01 ​M concentration of HDAP from Tafel polarisation curve. From electrochemical impedance (EIS) studies, it was confirmed that increase in concentration of HDAP led to enhancement of the charge transfer resistance. Both physical and chemical types of adsorptions were observed for the Schiff base via π-bonding electrons which obey Langmuir adsorption isotherm. The SEM picture revealed development of a thin layer on metallic surface. Quantum chemical evaluations were conducted to find out the mechanism of corrosion retardation power of HDAP.

Golpar leaves extract application for construction of an effective anti-corrosion film for superior mild-steel acidic-induced corrosion mitigation at different temperatures

The application of bio-compatible organic compounds from Golpar leaves as a green source to establish a protective layer on the steel surface is the main target of this study. So herein, the effect of environmental-friendly and cost-effective Golpar leaves extract (GLE) on the corrosion retardation of the mild-steel (MS) substance in HCl aggressive solution (1 M) is reported. The Fourier transform infrared (FT-IR) and ultraviolet-visible (UV–vis) tests were conducted to recognize the GLE functional groups. The effect of GLE on the topology and morphology of the steel surface subjected to the GLE-HCl solution was investigated via atomic force microscopy (AFM) and field emission scanning electron microscopes (FE-SEM), respectively. Accordingly, the heterogeneity and roughness of the steel surface decreased in the presence of the GLE. The deposition of a graphene-like film that consists of GLE phytochemicals was examined by Raman spectroscopy ( I D / I G = 0.60). The grazing incidence X-Ray diffraction (GIXRD) indicated the formation of inhibitor and iron complex layers over the surface. The contact angle (CA) outcomes demonstrated 45° enhancement of the metal surface hydrophobicity in the presence of GLE. The electrochemical impedance spectroscopy (EIS), potentiodynamic polarization spectroscopy (PDS), and weight loss measurements were utilized to survey the steel plates' corrosion resistance. The total resistance of 6.8, 8.1, 9.2, and 9.8 KΩ cm 2 was obtained at the concentrations of 400, 600, 800, and 1000 ppm, respectively. The results revealed that in the presence of 1000 ppm GLE, the inhibition activity was improved to up 91% after 10 h at 25 °C. The inhibition efficiency of GLE-contained solutions remained 90% even at 35 and 45 °C during 10 h of exposure, which is a significant number in comparison with most of the reported green inhibitors. According to the weight loss determinations, 90% surface coverage was attained after 5 h immersion in 1000 ppm GLE. Moreover, obeying Langmuir-isotherm the GLE organic compounds adsorbed on the steel substance and showed mixed (anodic/cathodic) corrosion inhibition activity. • The effect of GLE concentration on the MS corrosion protection in hydrochloric acid aqueous (1 M) solution was studied. • Addition of 1000 ppm GLE to the acidic media caused 91% inhibition efficiency and 92% surface coverage after 10 h of immersion. • Deposition of a hydrophobic and graphene-like film that consists of GLE phytochemicals was examined by Raman spectroscopy. • GLE acted as a mixed inhibitor in the acidic media and suppressed the corrosion reaction obeying Langmuir-isotherm.