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Al–air battery has been regarded as a promising new energy source. However, the self-corrosion of aluminum anode leads to a loss of battery capacity and a decrease in battery longevity, limiting its commercial applications. Herein, indole-2-carboxylic acid (ICA) has been added to 4 M NaOH as a corrosion inhibitor. Its impact on the self-corrosion of aluminum alloy and the enhancement of the functionality of Al–air batteries at various concentrations have been investigated. X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM) techniques have been used to examine the compositional and morphological alterations of aluminum alloy surfaces. Electrochemical and hydrogen evolution tests showed that indole-2-carboxylic acid is an efficient corrosion inhibitor in alkaline solutions, and its impact grows with concentration. Our findings demonstrated that when the inhibitor concentration is 0.07 M, the inhibition efficiency is 54.0%, the anode utilization rises from 40.2% to 79.9%, the capacity density increases from 1197.6 to 2380.9 mAh g−1, and the energy density increases from 1469.9 to 2951.8 Wh kg−1. In addition, theoretical calculations have been performed to support the experimental results. [ABSTRACT FROM AUTHOR]

Abstract REPO 4 (RE = Gd, Nd, La) ceramics with a monazite structure were fabricated by a chemical co-precipitation and calcination method. Hot corrosion tests were carried out in V 2 O 5 +Na 2 SO 4 molten salt at 800 °C, 900 °C and 1000 °C for 2 h and 10 h. The temperature and heat duration had little effect on the type of corrosion products in this study. However, GdPO 4 and REPO 4 (RE = Nd, La) revealed different hot corrosion behavior. Exposed to the molten salt, GdVO 4 and Gd 4 (P 2 O 7) 3 formed as the corrosion products for the GdPO 4 case, while an RE(P,V)O 4 (RE = Nd, La) solid solution was generated for NdPO 4 and LaPO 4 cases. The formation of the solid solution had less damage to the original microstructure, which benefited the hot corrosion resistance of the ceramics. From the crystallographic characteristics of rare earth phosphates/vanadates and a thermodynamics perspective, the hot corrosion mechanisms of REPO 4 (RE = Gd, Nd, La) are discussed. [ABSTRACT FROM AUTHOR]

Abstract A new pyrazolotriazole derivative, namely, 1-acetyl-6-methyl-1H-pyrazolo [3,2-c][1,2,4]triazole (APT) was synthesized. The corrosion inhibition performance of APT on carbon steel in 1 M hydrochloric acid solution was investigated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) methods. The results showed that the inhibition efficiency of APT increases with concentration and attains its maximum of 93% at 10−3 M. The potentiodynamic polarization study suggests that APT acts as mixed type inhibitor. The EIS studies show that APT produces a covering layer at the metal/electrolyte interface. The adsorption of this compound on steel surfaces followed a Langmuir adsorption isotherm. DFT calculations at the B3LYP level of theory and the analyses of frontier orbitals allow the determination of the active adsorbed sites of APT on the metal surface, and molecular dynamics simulations further illustrate the most reasonable adsorption configuration. Graphical abstract Image 1 Highlights • Synthesis of a new 1-acetyl-6-methyl-1H-pyrazolo [3,2-c][1,2,4]triazole derivative (APT). • 3D structure is elucidate using XRD and confirmed by DFT calculations. • APT corrosion inhibition on carbon steel in 1 M HCl solution is investigated. • The inhibition efficiency of APT increases with concentration. • MD simulations suggest the parallel adsorption model of APT on iron substrate. [ABSTRACT FROM AUTHOR]

The mutually corroborated electrochemical measurements and theoretical calculations were used to investigate the corrosion inhibition performances of purpald (4-amino-3-hydrazino-5-mercapto-1,2,4-triazole, AHMT) and its synergistic effect with tartaric acid (TA) on mild steel in 0.5 M H2SO4 solution. The experimental results show that the inhibition efficiency increases with the concentration of AHMT and increases further when TA exists. Density functional theory (DFT) calculations were performed to interpret the measured data and trends observed in the electrochemical studies. Furthermore, molecular dynamic simulation revealed a nearly flat configuration for molecules on metal surface with negative adsorption energies in a sequence agreed with experimental observation. [ABSTRACT FROM AUTHOR]

Ba 2 REAlO 5 (RE = Dy, Er, Yb) powders were synthesized by a solid state reaction method, followed by cold pressing and sintering to produce pellets for hot corrosion tests. When exposed to V 2 O 5  + Na 2 SO 4 molten salt at 900 °C and 1000 °C for 4 h and 20 h, REVO 4 , Ba 3 (VO 4 ) 2 and BaAl 2 O 4 formed as corrosion products due to chemical interactions between the ceramics and the molten salt, which were temperature and time independent. After the hot corrosion tests at 1000 °C, continuous, dense reaction layers with a thickness of ∼80 μm formed on the sample surfaces, which had an effective function on suppressing further penetration of the molten salt. The hot corrosion mechanisms of Ba 2 REAlO 5 are proposed based on Lewis acid-base rule, phase diagrams and thermodynamics. From a thermodynamics perspective, the molten salt directly reacting with Ba 2 REAlO 5 is difficult compared with Yb 2 O 3 , Al 2 O 3 and BaO. [ABSTRACT FROM AUTHOR]

The inhibition performance of domperidone on the corrosion of copper in different concentration of HCl solution has been investigated by electrochemical, weight loss, and surface analysis, and theoretical calculation methods. Results indicate that domperidone was found to be an effective inhibitor with the inhibition efficiency as high as 98.5% when the HCl concentration was 0.01 M, and the corrosion rate of copper increased with the increment of HCl concentration from 0.001 to 1 M. The potentiodynamic polarization results revealed that domperidone can be seen as a mixed type inhibitor when the HCl concentration was high (1 and 0.1 M), while it acted as a cathodic inhibitor for copper at low HCl concentrations (0.01 and 0.001 M). The potentiodynamic polarization results revealed that domperidone can be seen as mixed-type or cathodic inhibitor as the HCl concentration changes. Scanning electron microscopy studies indicated the formation of protective films of inhibitor molecule on copper surface. Besides, density functional theory-based quantum chemical calculations and molecular dynamics simulations showed the electronic structure of domperidone and its optimized adsorption configuration on copper surface, which could account for the experimental findings. [ABSTRACT FROM AUTHOR]

3.5 mol% Yb 2 O 3 stabilized zirconia (YbSZ) doped with 10 mol% TiO 2 (Ti-YbSZ) was produced, and its hot corrosion behavior exposed to Na 2 SO 4 + V 2 O 5 molten salt was investigated. The as-fabricated ceramic mainly consists of metastable tetragonal (t′) phase. When exposed to the molten salt at 700 °C, 800 °C, 900 °C and 1000 °C for 2 h and 10 h, YbVO 4 and m-ZrO 2 formed as corrosion products due to chemical reactions between the ceramics and the salt. Ti 4+ in Ti-YbSZ solid solution keeps stable during the hot corrosion tests, which acts as a stabilizer for ZrO 2 , preventing total decomposition of the t′ phase. After the hot corrosion tests, Ti-YbSZ has an apparently lower m phase content than Y 2 O 3 doped Zirconia and YbSZ, indicative of better corrosion resistance. The hot corrosion mechanism of Ti-YbSZ is proposed based on Lewis acid-base rule, phase diagrams and thermodynamics. [ABSTRACT FROM AUTHOR]

The mutually corroborated density functional theory (DFT) and molecular dynamics (MD) simulation methodology were employed to evaluate the inhibition performance of three thiourea derivatives (Inh1, Inh2, and Inh3) on carbon steel corrosion. Experimental results have shown that the corrosion rate follows the order: Inh3 > Inh2 > Inh1. Quantum chemical descriptors such as the frontier orbital energies ( E HOMO and E LUMO ), the energy gap between E LUMO and E HOMO (Δ E ), dipole moment (μ), and Fukui index have been calculated and discussed. Some significant factors such as solvent, temperature, and coverage have been considered when investigating the adsorption of aforementioned thiourea derivatives on Fe(1 1 0) surface. Our results provide important atomic/molecular insights into the anticorrosive mechanism of inhibitor molecules, which could help in understanding the organic-metal interface and designing more appropriate organic corrosion inhibitors. [ABSTRACT FROM AUTHOR]

Hot corrosion behavior of Ba 2 REAlO 5 (RE = Dy, Er, Yb) ceramics exposed to V 2 O 5 molten salt at 900 °C and 1000 °C was investigated, providing a better understanding of their corrosion resistance as promising thermal barrier coatings. Obvious surface reactions occurred forming continuous, dense reaction layers on the top surfaces of the samples, the types of corrosion products being temperature and time independent. After heat treatment for 4 h and 20 h in V 2 O 5 salt at the two temperatures, the corrosion products consisted of REVO 4 , Ba 2 REV 3 O 11 and BaAl 2 O 4 (RE = Dy, Er, Yb). Prolonged heat treatment and elevated temperature promoted the growth of Ba 2 REV 3 O 11 and REVO 4 grains. The reaction layer had a positive function on suppressing further penetration of the molten salt. The mechanism by which the corrosion reaction occurs is proposed based on Lewis acid-base rule, phase diagrams and thermodynamics. [ABSTRACT FROM AUTHOR]

Steel is an important material in industry. Adding heterocyclic organic compounds have proved to be very efficient for steel protection. There exists an empirical rule that the general trend in the inhibition efficiencies of molecules containing heteroatoms is such that O < N < S. However, an atomic-level insight into the inhibition mechanism is still lacked. Thus, in this work, density functional theory calculations was used to investigate the adsorption of three typical heterocyclic molecules, i.e. , pyrrole, furan, and thiophene, on Fe(110) surface. The approach is illustrated by carrying out geometric optimization of inhibitors on the stable and most exposed plane of α-Fe. Some salient features such as charge density difference, changes of work function, density of states were detailedly described. The present study is helpful to understand the afore-mentioned experiment rule. [ABSTRACT FROM AUTHOR]

La 2 Ce 2 O 7 (LC) has been considered as one of the promising thermal barrier coating (TBC) candidates for operating above 1250 °C. In this work, a LC/yttria stabilized zirconia (YSZ) double ceramic layer TBC was produced by electron beam physical vapor deposition (EB-PVD). Hot-corrosion behavior of the LC/YSZ TBC exposed to Na 2 SO 4 +V 2 O 5 or V 2 O 5 salt at 900 °C was investigated. After hot corrosion in Na 2 SO 4 +V 2 O 5 salt for 4 h, a porous layer mainly composed of (La 0.75 Ce 0.25 )VO 4 and CeO 2 was formed on the LC layer. In V 2 O 5 salt, the molten salt directly reacted with La 2 Ce 2 O 7 solid solution, leading to the formation of (Ce 0.5 La 0.5 )VO 4 . The hot corrosion mechanisms of the LC/YSZ TBC in the two molten salts were discussed. [ABSTRACT FROM AUTHOR]

In this work, we used experimental and theoretical calculation methods to investigate the corrosion inhibition nature of banana leaves water extract (BLWE) for X70 steel at 1 mol/L hydrochloric acid environment. The data of electrochemical tests manifest that the hydrochloric acid medium will accelerate the corrosion of X70 steel with increasing temperature. The charge transfer resistance dropped sharply from 55 Ω cm2 at 298 K to 18.4 Ω cm2 at 313 K. After adding BLWE in hydrochloric acid solution, the anti-corrosion efficiency of banana leaves extract for X70 steel can be maintained at about 90%. BLWE can simultaneously inhibit the anodic and cathodic reactions of X70 steel in hydrochloric acid solution, so it is mixed-type inhibitor. Surface morphology analysis strongly shows that BLWE can effectually restrain the corrosion of X70 steel. BLWE adsorption at the X70 steel surface is accord with Langmuir single-deck adsorption. Quantum chemical (QC) calculation and molecular dynamics simulations (MDS) have shown that (S)-2-amino-3-(4-hydroxyphenyl)propanoic acid (AHP), 3-(2-aminoethyl)-1H-indol-5-ol (ATI), and 3,4-Dihydroxycinnamic Acid (DDA) in BLWE can show excellent anti-corrosion character. QC calculation results show that AHP, ATI and DDA have small dipole moment values. The small dipole moment value is favorable the accumulation of inhibitor molecule on the X70 steel surface, thereby forming a denser barrier film. MDS results show that AHP, ATI and DDA can be adsorbed on the Fe (110) surface in parallel to obtain the maximum coverage. Unlabelled Image • Electrochemical test data indicate BLWE belong to the mixed-type corrosion inhibitor. • Surface characteristics analysis provided that BLWE exhibit excellent corrosion inhibition nature. • BLWE adsorb on the Fe/solution surface in accordance with the Langmuir model. [ABSTRACT FROM AUTHOR]

The corrosion inhibition performance of 5-Mercapto-1-phenyltetrazole (MPT) has been studied using theoretical calculation and abundant experimental methods. Electrochemical experiments show that MPT show high-efficiency corrosion inhibition ability for Q235 steel in H 2 SO 4 environment. The concentration of MPT is 5 mM, the anti-corrosion inhibition efficiency (η) is 98.1% at the 298 K. Besides, the anti-corrosion nature of MPT can keep about 98% in the temperature district of 298 K to 318 K. The test results of atomic force microscope (AFM) and scanning electron microscope (SEM) strongly prove that MPT can effectively adsorb at the Q235 steel interface, thereby effectively inhibiting the Q235 steel corrosion. The adsorption of MPT at the interface of Q235 steel conforms to Langmuir single-deck adsorption, and both physical and chemical adsorption exist. The theoretically calculated surface MPT has a large dipole moment and a small energy gap value, so it can exhibit high-quality corrosion inhibition performance. Unlabelled Image • Electrochemical data indicate MPT belong to the mixed-type inhibitor. • Surface characteristics analysis provided that MPT exhibit outstanding anti-corrosion nature. • MPT adsorb on the Q235 steel surface in accordance with the Langmuir model. • Theoretical calculation data show that MPT can exhibit good anti-corrosion performance. [ABSTRACT FROM AUTHOR]

• An eco-friendly drug losartan potassium (LP) is developed as a superior mixed-type inhibitor for steel corrosion. • The multi-anchored film of LP is formed on steel substrate. • Theoretical modelling provides deep insights into the inhibition performance of LP. The present study aimed to find a suitable alternative for traditional and hazardous corrosion inhibitors. A green antihypertensive drug-Losartan potassium (LP) with superior corrosion protection ability was developed for the first time. Gravimetric method, potentiodynamic polarization, AC impedance, and scanning vibrating electrode technique (SVET) were combined to evaluate the corresponding inhibition performance towards Q235 steel in HCl medium. The results indicated that LP exhibited superior mixed-type corrosion protection to steel at different temperatures owing to the formation of compact and ordered LP-adsorption film on steel surface. Specifically, the inhibition performance values increased to 88.9%, 91.8%, and 92.0% for 5 mM LP at 298, 308, and 318 K, respectively. Meanwhile, N-Fe bond from X-ray photoelectronic spectroscopy (XPS) implied multiple anchoring interaction between steel and LP with nitrogen atoms as active sites. Based on DFT calculation and molecular dynamics (MD) simulation, the obtained low energy gap (Δ E) and high E binding values as well as radial distribution function (RDF) analysis represented strong chemisorption of LP on Fe substrate, which theoretically explained the favorable inhibition effectiveness of LP compound at molecular or atomic level. [ABSTRACT FROM AUTHOR]

A new type of Equisetum arvense aerial part (EAAP) extract was ready to be tested as a corrosion inhibitor for steel-based parts in Multi-stage flash (MSF) segments while the segments were being acid cleaned. The EAAP extract was identified using Fourier-transform infrared (FTIR) and High-performance liquid chromatography (HPLC). When compared to the specimen exposed to blank solution, EAAP extract molecules covered about 97% of the carbon steel surface in 2 M HCl solution, and the corrosion rate was reduced to 0.58 ± 0.02 μg cm−2 h−1 at 300 mg l−1. EAAP extract tends to have a blended impact on both anodic and cathodic sites on the surface of carbon steel. The thermodynamic activation factors are substantially higher in the presence of extract solution than in the absent of extract, demonstrating that the carbon steel surface would corrode slowly in the presence of EAAP extract. Theoretical models were used to validate the adsorption of EAAP extract on steel surfaces. [ABSTRACT FROM AUTHOR]

In this work, we studied food flavor 2-Furfurylthio-3-methylpyrazine (FFM) as the green inhibitor for copper corrosion H 2 SO 4 solution. Electrochemical experiment data show that FFM can exhibit prominent anti-corrosion nature for copper in H 2 SO 4 medium in the temperature range of 298 K to 313 K. Potentiodynamic polarization curve results show that the corrosion inhibition efficiency of FFM can be as high as 97.9% at a concentration of 5 mmol/L. The surface morphology test results show that adding 5 mmol/L FFM in H 2 SO 4 medium, the copper sample is still relatively flat after soaking for 20 h, and the roughness values is only 7.84 nm. The XPS experimental results show that the S and N atoms in the FFM molecule can form N Cu and S Cu bonds on the copper surface to generate chemical adsorption. Besides, the FFM adsorption on the copper/solution surface conforms to the Langmuir monolayer adsorption model. The theoretical calculation results also prove that FFM can exhibit prominent anti-corrosion nature for copper in sulfuric acid medium. Unlabelled Image • Electrochemical test data indicates FFM belong to mixed-type corrosion inhibitor. • Surface topography results manifest that FFM exhibit excellent ant-corrosion nature. • Theoretical calculation results show that FFM can exhibit excellent corrosion inhibition performance. [ABSTRACT FROM AUTHOR]

Locust Bean Gum (LBG) was studied as a novel and eco-friendly corrosion inhibitor using experimental and theoretical calculation methods. These research methods include open-circuit potential (OCP), potentiodynamic polarization curves (PDP), electrochemical impedance spectroscopy (EIS), surface morphology analysis (AFM and SEM), quantum chemical calculations (QCC), and molecular dynamics simulations (MDS). Potentiodynamic polarization test data shows that when the concentration of LBG is 5 mM at 298 K, the corrosion inhibition efficiency of LBG is 89.8% for Q235 steel in 0.5 M H 2 SO 4 solution. AFM and SEM morphology maps convincingly confirm the data of electrochemical tests. The adsorption of LBG on Q235 steel/solution interface was consistent with Langmuir single-layer model. In addition, theoretical calculations show that LBG can show excellent corrosion inhibition performance. Unlabelled Image • Electrochemical test data indicates LBG is mixed-type corrosion inhibitor. • SEM and AFM data provided that LBG exhibit excellent anti-corrosion nature. • LBG adsorb onto the Fe surface in accordance with the Langmuir model. [ABSTRACT FROM AUTHOR]

• Waterborne polyurethane/polydopamine graphene oxide(WPU/PGO) are prepared simply. • The well-dispersed PGO effectively improves the dispersibility and stability of WPU. • WPU coating with 0.5 wt% PGO shows the most excellent comprehensive properties. In this work, a polydopamine (PDA) - functionalized graphene oxide (GO) nanocomposite was prepared by a simple and eco-friendly approach. The results recorded via FTIR, UV–vis absorbance spectroscopy, Raman, XPS spectral, as well as atomic force microscope (AFM) demonstrated the effective modification and overlay of PDA on the surface of GO. GO-PDA can be stably dispersed in aqueous solution, and GO-PDA was incorporated into waterborne polyurethane (WPU) by solution blending. The examinations of particle size analysis and zeta potential showed that the incorporation of GO-PDA can effectively improve the uniformity and stability of polyurethane aqueous dispersion. The observation results of SEM verified that PDA promoted the uniform dispersion of GO nanosheets in polymer coatings. The electrochemical impedance spectroscopy and salt spray test of the steel substrates coated with composite coatings confirmed that the incorporation of 0.5 wt% GO - PDA significantly enhanced the anti - corrosion performance of WPU. Compared with previous reports, the incorporation amount of GO-PDA was drastically reduced, and the corrosion protection of coating was effectively improved. In addition, the pull-off and contact angle tests also demonstrated improved adhesion strength and hydrophobicity of the coating. Only water was used as solvent in the whole preparation process of coating and its excellent corrosion protection make it promising in engineering. [ABSTRACT FROM AUTHOR]

The corrosion of carbon steel is always a very serious issue, and the addition of corrosion inhibitors is an effective approach to prohibiting the corrosion of carbon steel. Because expired drugs are environmentally friendly, green, and non‐toxic; thus, this work provides a new idea for the treatment of expired drugs. The expired flunarizine hydrochloride (FH) is used as corrosion inhibitors for Q235 steel, investigating the corrosion inhibition efficiency of expired FH with different concentrations for carbon steel and illustrating the corrosion inhibition mechanism. Electrochemical impedance and Tafel curves are used to investigate the corrosion inhibition of carbon steel under 1 M HCl solution with different concentrations of the expired FH, and the corrosion efficiency is calculated according to the immersion tests, and the corrosion inhibition efficiency is more than 88.5%. Scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), and Raman spectroscopy strongly support the results of the electrochemical experiment. Besides, the simulation results also provide the strong supports for the experimental results. [ABSTRACT FROM AUTHOR]

Corrosion has caused serious damage to our society, lives and environments. Although the corrosion of metals and their alloys was inevitable, it was controllable using the certain protection method. Using corrosion inhibitors was a feasible strategy to protect metals and alloys from corrosion. Traditional inorganic and organic inhibitors were toxic and expensive. Growing ecological awareness and economic challenges prompted people to look for cheap, efficient, safe and nontoxic green corrosion inhibitors. In this review, the related researches of nitrogen-containing heterocyclic compounds (NCHCs) and carbon dots (CDs) as green corrosion inhibitors were summarized. The chemical compositions of several nitrogen-containing heterocyclic compounds (NCHCs) and carbon dots (CDs) and their corrosion inhibition efficiency in aggressive solutions are reviewed. The corrosion inhibition mechanisms of these environmental friendly corrosion inhibitors on metal surfaces were discussed in detail. This review briefly introduced the corrosion determination method, and expounded the application of surface analysis technology and computational chemistry tools in understanding the anti-corrosion mechanism of green and efficient corrosion inhibitors. [ABSTRACT FROM AUTHOR]

Calcium-magnesium-alumina-silicate (CMAS) attack has been considered as one of the significant failure mechanisms for thermal barrier coatings (TBCs). In this study, CMAS corrosion behavior of Ba 2 DyAlO 5 is investigated at 1300 °C and 1350 °C for 0.5 h, 4 h, 12 h and 24 h. The results indicated that Ba 2 DyAlO 5 had high resistance to CMAS infiltration for prolonged durations (24 h), ascribed to the rapid formation of crystallization phases by chemical reaction between Ba 2 DyAlO 5 and CMAS. The corrosion products with a main constitution of Ca 2 Dy 8 (SiO 4 ) 6 O 2 , Ba 1.31 Ca 0.69 SiO 4 , BaAl 2 O 4 and Dy 2 O 3 phases formed a sealing layer on the sample surfaces, which can effectively suppress further penetration of the molten CMAS. The associated mechanism was discussed. [ABSTRACT FROM AUTHOR]

The utilization of organic compounds has been established to be perhaps the best, most proficient, and most powerful method for controlling corrosion. Organic compounds extend into benefits by complexing at the metal-environment interface applying their electron-dense centers, which are known as binding centers. Though, because they have small molecular size, they do not have satisfactory corrosion protection. Accordingly, there is an exceptional requirement for major atomic changes. Toward this path, unique accentuation is put on the utilization of epoxy resins (ERs)-based synthetic monomers as inhibitors for corrosion. The nature of the structure that includes polar functional groups makes the monomers adsorb strongly on the metal surface and give remarkable metal protection. This review report gives a concise outline of the most recent improvements in the utilization of ERs as corrosion inhibitors. This report gives a short outline of the consumption and general utilization of various sorts of ERs and corrosion inhibition processes. [ABSTRACT FROM AUTHOR]

The adsorption behavior and inhibition mechanism of five synthesized bis-azo dye (BAD) derivatives on the corrosion of iron in aerated HNO 3 and NaOH were investigated by performing potentiostatic polarization, weight loss (WL), thermometric and UV–visible spectra measurements. DFT calculations is applied to study the correlation between corrosion inhibition and global reactivity descriptors such as: E HOMO , E LUMO , molecular gap (Δ E ), the dipole moment ( μ ), the global hardness ( η ), softness( S ), electronegativity ( χ ), proton affinity ( PA ), electrophilicity ( ω ), nucleophilicity ( ɛ ), electrons transferred from inhibitors to metal surface (Δ N ), initial molecule-metal interaction energy (Δ ψ ), total electronic energy ( E ) and the energy change during electronic back-donation process (Δ E b-d ). To mimic the real environment of corrosion inhibition, molecular dynamic (MD) simulations in aqueous phase have also been modelled consisting of all concerned species (inhibitor molecule, H 2 O, H 3 O + ion, NO 3 − ion, OH − and Fe surface). The results confirmed that BAD molecules inhibit iron by adsorption behavior through donating and accepting electrons together with the formation of [Fe (II) and Fe (III)—BAD] chelate complex compounds. BAD's behavior is mainly chemisorption with some physisorption obeyed Frumkin and that of El-Awady adsorption isotherm. Kinetic parameters such as: ( K b , 1/y , K ads , f , Δ G ° ads ) have been determined and discussed. Binding energies of BAD molecules on Fe (110) surface followed the order: BAD _ 2 >  BAD _ 1 >  BAD _ 3 >  BAD _ 4 >  BAD _ 5 . Theoretical results were found to be consistent with the experimental data reported. Our results provide important atomic/molecular insights into the anticorrosive mechanism of inhibitor molecules, which could help in understanding the organic-metal interface and designing more appropriate organic corrosion inhibitors. [ABSTRACT FROM AUTHOR]

Calcium-magnesium-alumina-silicate (CMAS) attack has been regarded as one of the significant failure mechanisms for thermal barrier coatings (TBCs). In this study, CMAS corrosion behavior of BaLa 2 Ti 3 O 10 , a novel TBC material, is investigated at 1300 °C and 1350 °C for 0.5 h, 4 h, 12 h and 24 h. Results reveal that BaLa 2 Ti 3 O 10 has high resistance to molten CMAS infiltration, attributable to the formation of a dense reaction layer. X-ray diffraction, scanning electron microscope, energy dispersive spectroscope, transmission electron microscope confirm that the layer consists of apatite, celsian and perovskite phases. With increased corrosion duration, the layer retains good phase stability and the thickness increases. The formation of corrosion products and the reaction layer are discussed according to a dissolution-reprecipitation mechanism and the optical basicity theory. [ABSTRACT FROM AUTHOR]

LaPO 4 powders were produced by a chemical co-precipitation and calcination method. The ceramic exhibited a monazite structure, kept phase stability at 1400 °C for 100 h, and had low thermal conductivity (~ 1.41 W/m K, 1000 °C). LaPO 4 /Y 2 O 3 partially stabilized ZrO 2 (LaPO 4 /YSZ) double-ceramic-layer (DCL) thermal barrier coatings (TBCs) were fabricated by air plasma spray. The LaPO 4 coating contained many nanozones. Thermal cycling tests indicated that the spallation of LaPO 4 /YSZ DCL TBCs initially occurred in the LaPO 4 coating. The failure mode was similar to those of many newly developed TBCs, probably due to the low toughness of the ceramics. LaPO 4 /YSZ DCL TBCs were highly resistant to V 2 O 5 corrosion. Exposed to V 2 O 5 at 700–900 °C for 4 h, La(P,V)O 4 formed as the corrosion product, which had little detrimental effect on the coating microstructure. At 1000 °C for 4 h, a minor amount of LaVO 4 was generated. [ABSTRACT FROM AUTHOR]

Nanostructured GdPO 4 coatings, designed as the outer layer of double-ceramic-layer thermal barrier coatings (DCL-TBCs), were produced by air plasma spraying (APS). The coatings have close chemical composition to that of the agglomerated particles used for thermal spray. Nanozones with porous structure are embedded in the coating microstructure, having a percentage of ~30%. Hot corrosion tests of the coatings were carried out in V 2 O 5 and Na 2 SO 4 +V 2 O 5 salts at 900 °C for 4 h. Results indicate that dense reaction layers, consisting of GdVO 4 and Gd 4 (P 2 O 7 ) 3 , form on the coating surfaces, which could suppress further penetration of the molten salts. In the V 2 O 5 molten salt, the reaction layer is thicker and less molten salt trace could be found beneath the layer. [ABSTRACT FROM AUTHOR]

Sodium dodecyl benzene sulfonate (SDBS) was investigated as an eco-friendly inhibitor for zinc corrosion in 26% NH 4 Cl solution using corrosion experiments and theoretical calculations. Gravimetric and electrochemical results reveal that SDBS is an anodic inhibitor with excellent inhibition efficiency, which is further confirmed by field emission scanning electron microscope (FE-SEM) and atomic force microscopy (AFM) observation. The inhibitory effect diminishes with positive shift of potential, exhibiting a desirable characteristic for battery application. Despite the inhibition efficiencies decrease as increasing temperature from 298 to 328 K, the compound still shows favorable inhibitive ability at each temperature. In addition, the adsorption of SDBS on zinc surface obeys Langmuir adsorption model. Quantum chemical calculations and molecular dynamic simulations were further performed to correlate the adsorption mechanism with the structure of SDBS molecule. [ABSTRACT FROM AUTHOR]

• A novel fused heterocyclic quaternary ammonium salt (BQD) was synthesised using a one-pot method, which can be easily operated and was increased the effective content of BQD in the product to 50 %. • The performance of synergy and inhibition of different compounding agents and BQD in acid solution were studied by different evaluative methods. • Molecular simulations of three systems of BQD corrosion inhibitor were carried out to explain the corrosion inhibition mechanism from a microscopic point of view. A novel fused heterocyclic quaternary ammonium salt (BQD) corrosion inhibitor was developed using the one-pot synthesis method, which employed quinoline and benzyl chloride. The one-pot synthesis method was easy to operate and successfully increased the effective BQD content to 50 %, aiming to provide an effective acidic corrosion inhibitor. The corrosion inhibition performance of BQD on N80 steel sheets in 20 % HCl solution was evaluated by weight loss and electrochemical tests. The synergistic inhibition between BQD and different compounding agents was investigated. The results indicated that BQD possessed good inhibition performance at 363 K. A corrosion inhibition rate of 99.17 % was achieved at an ultra-low concentration (0.05 % BQD). In addition, a synergistic performance was observed when combining BQD with either KI or urotropine. The system of BQD with urotropine presented the best inhibition performance, and the corrosion rate was further reduced to 2.87 g·m−2·h−1. The adsorption of the inhibitor system on the N80 steel surface was followed by Langmuir adsorption isotherm, which adsorbed on the N80 steel surface by chemical adsorption. The inhibition mechanism of BQD on N80 steel was studied by scanning electron microscopy (SEM) measurement, energy dispersive spectroscopy (EDS) analysis, contact angle determination, and molecular dynamics (MD) simulation. BQD can be adsorbed parallel to the surface of a steel sheet by using a conjugate plane consisting of a five-membered nitrogen-containing heterocycle and two six-membered rings on either side of the five-membered heterocycle as the reference plane. Therefore, BQD forms an adsorption protection film on the steel sheet surface, which can effectively slow down metal corrosion by acid solution. [ABSTRACT FROM AUTHOR]

• • Electrochemical test data indicate Pyracantha fortuneana alcohol extracts belong to mixed-type corrosion inhibitor. • • The Pyracantha fortuneana alcohol extracts adsorb on the Cu in accordance with the Langmuir model. • • Theoretical calculation provide in-depth understanding of the experimental results. Compared with traditional copper corrosion inhibitors, Pyracantha fortuneana alcohol extracts are derived from natural plants, will not cause environmental pollution after use, and are in line with the concepts of green chemistry and sustainable development. In this study, Pyracantha fortuneana alcohol extracts (PFAE) were obtained by ethanol soaking extraction method. PFAE, a novel degradable green corrosion inhibitor, has been investigated by experiments and theoretical calculations for its anti-corrosion performance of copper in H 2 SO 4 solution. Electrochemical experiments have demonstrated a pronounced increase in corrosion inhibition efficiency (η) as the concentration of PFAE rises. At a PFAE concentration of 600 mg/L, the inhibition efficiency can exceed 95 %. Additionally, the electrochemical method was used to investigate how the effect of soaked time on its anti-corrosion performance. After 4 h of immersion in a H 2 SO 4 solution containing PFAE, the copper could still maintain more than 80 % of the anti-corrosion performance. The results of surface morphology analysis demonstrate that after adding PFAE, the roughness of the copper sample is significantly reduced. This provides intuitively evidence that PFAE can indeed proficiently inhibit copper corrosion within a sulfuric acid solution. According to the study of the adsorption model, it was found that the adsorption behavior of PFAE onto the copper surface adheres to the Langmuir monolayer adsorption model. Moreover, the findings indicate the coexistence of both physical and chemical adsorption mechanisms. The findings of molecular dynamics simulations (MD) and quantum chemistry (QC) calculations indicate that the six active components of PFAE can display strong anti-corrosion capability. [ABSTRACT FROM AUTHOR]

There are various types of procedures in the petroleum industries that uses 15% hydrochloric acid solution. Use of HCl often results into corrosion of stainless steel (SS) 410. In this study, extract prepared from waste material, Beta vulgaris peel has been explored as green corrosion inhibitor for SS 410 in 15% HCl solution. Potentiodynamic polarization study showed maximum 90.17% corrosion inhibition efficiency at 4 g/L of B. vulgaris peel extract in 15% HCl solution. Scanning electron, atomic force microscopy and X-rays diffraction study confirmed the adsorption of B. vulgaris peel extract on the SS 410 surface. The peel extract followed Langmuir adsorption isotherm, which confirmed monolayer formation on the surface of SS 410. Vitexin was found to be main phytochemical responsible for the anti-corrosive effect according to the theoretical and computational studies. Vitexin and SS 410 interactions were studied by molecular simulation. Overall, the B. vulgaris peel extract has shown anti-corrosive behaviour against SS 410 surface in 15% hydrochloric acid. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Both DDA, DPD show excellent corrosion inhibition performance for cobalt. • Surface morphology of cobalt samples were examined by AFM and SEM. • The adsorption process of DDA, DPD follows Langmuir adsorption isotherm. • Experimental results were supported by DFT and molecular dynamics simulations. • The solubility and toxicity of DDA, DPD were evaluated by theory. Cobalt, as the barrier layer material for 14 nm copper interconnection, has been widely applied owing to its superior characteristics of low resistivity, excellent adhesion performance and blocking properties for copper. Most of the preciously developed cobalt corrosion inhibitors under weak alkaline condition are toxic, low water solubility, and limited to traditional experimental research. In this work, 3,3-dithiodipropionic acid (DDA), 2,2-dibenzamidodiphenyl disulfide (DPD) as potential corrosion inhibitors for cobalt in NH 4 Cl and H 2 O 2 media under alkaline environment were investigated. Electrochemical experiments, surface morphology characterization, quantum chemical calculation and molecular dynamic simulation were combined to analyze the corrosion inhibition ability and mechanism. The experimental and theoretical results present that these disulfide derivatives can inhibit the corrosion behavior of cobalt surface effectively in ammonium-based aqueous solutions. When the concentration of inhibitors was 0.5 wt%, the corrosion inhibition efficiency of DDA, DPD reach up to 92.9%, 91.41%, respectively. Their favorable capability is attributed to the dense adsorption films following the Langmuir adsorption isotherm. Besides, these two inhibitors show excellent performance of galvanic corrosion inhibition at the Co/Cu interface, which is consistent with the shift tendency simulations for binding to Co/Cu substrates. The results of water solubility and toxicity tests indicate that DDA is more suitable for industrial applications. [ABSTRACT FROM AUTHOR]

The inhibitive effect and inhibition mechanism of l-lysine derivatives, namely α-N-benzyloxycarbonyl-l-lysine (α-NL) and ε-N-benzyloxycarbonyl-l-lysine (ε-NL), on the corrosion of carbon steel in 0.5 M H2SO4 solution were investigated by electrochemical technique, weightlessness test, scanning electron microscope, atomic force microscope, infrared attenuated reflectance spectroscopy and quantum chemical calculation. The results showed that α-NL and ε-NL as moderate cathodic inhibitors mainly inhibited the cathodic reaction of carbon steel in 0.5 M H2SO4 solution, and the terminal substituted ε-NL showed better corrosion inhibition than the α-N-benzyloxycarbonyl protected α-NL. Their inhibition efficiencies increased with the increase in inhibitor concentration, and the inhibition efficiency of α-NL and ε-NL with concentration of 10 mmol can reach 53.4% and 61.5%, respectively, but decreased with rising temperature. The adsorption of investigated inhibitors on the surface of carbon steel obeyed the modified Langmuir isotherm and El-Awady thermodynamic-kinetic model, and the thermodynamic and kinetic parameters were determined to discuss the mechanism of inhibition of α-NL and ε-NL. Moreover, Quantum chemical calculation gave further insight into the inhibition mechanism of α-NL and ε-NL and was employed to reveal the reasons for their differences in inhibition performance. [ABSTRACT FROM AUTHOR]

In this paper, the corrosion inhibition performance of eco-friendly corrosion inhibitors 1-propyl-3-methylimidazolium bromide ([PrMIm]Br), 1-aminopropyl-3-methylimidazolium bromide ([APMIm]Br) and 1,4-bis(3-methylimidazolium-1-yl)butane dibromide ([BMImB]Br 2) was investigated for mild steel (MS) in H 2 SO 4 medium via experimental and theoretical methods. The results of electrochemical experiments show that the order of their corrosion inhibition is [BMImB]Br 2 > [APMIm]Br > [PrMIm]Br. The corrosion inhibition efficiency of [BMImB]Br 2 , [APMIm]Br and [PrMIm]Br are 92.9%, 88.0%, and 69.6% at the 303 K, respectively. The scanning electron microscope (SEM) morphology test results vividly prove that [BMImB]Br 2 has higher corrosion inhibition performance for [APMIm]Br and [PrMIm]Br. Weight loss experiments show that [BMImB]Br 2 and [APMIm]Br can still exhibit good corrosion inhibition nature with increasing temperature. Besides, the adsorption of three imidazole ionic liquids on the MS/solution interface is conform to Langmuir single-layer model, and they belong to the physical and chemical adsorption on the MS surface. Theoretical calculations explain their corrosion inhibition mechanism from an atomic or molecule perspective. • Electrochemical test data indicate [BMImB]Br 2 , [APMIm]Br and [PrMIm]Br belong to mixed-type corrosion inhibitor. • The corrosion inhibition performance is [BMImB]Br 2 > [APMIm]Br > [PrMIm]Br. • The corrosion inhibition mechanism was revealed by thermodynamic and kinetic analysis and theoretical calculation. [ABSTRACT FROM AUTHOR]

The synergistic corrosion inhibition performance of 3, 3′-Diethylthiadicarbocyanine iodide (DI) and Thioflavin T (TT) for copper in 0.1 M HCl solution was investigated by electrochemical methods, weight loss tests and SEM. Besides, through the thermodynamics and kinetics analysis, the effects of temperature and concentration were explored. The XPS was also applied to study synergistic inhibition mechanism between anions and cations of ionic liquid. The results indicated that the inhibitor molecules interacted with copper forming protective film to inhibit corrosion by physical and chemical adsorption, also the organic cations and halogen ions had synergistic corrosion inhibition. With theoretical calculation and molecular dynamics simulation, the experiment validity was further assessed. Unlabelled Image • The studied inhibitors are environmentally friendly. • The inhibition efficiency is excellent up to 99.81%. • Theoretical calculations further provide evidence for experiments. • A good synergistic corrosion inhibition exists between anion and anion in ionic liquid. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Food flavors of 2-isobutylthiazole (ITT) and 1-(1,3-Thiazol-2-yl)ethanone (TEO) for the corrosion inhibition of X65 steel in H 2 SO 4 were studied by electrochemical methods, atomic force microscopy (AFM), scanning electron microscopy (SEM) and theoretical calculations. Electrochemical experiments show that ITT and TEO can effectively inhibit the corrosion of cathode and anode of X65 steel, and they are mixed-type corrosion inhibitors. Surface topography analysis (SEM and AFM) also visually demonstrate that ITT and TEO form an effective barrier film on the X65 steel surface to isolate the corrosive medium. Theoretical calculations profoundly explain the inhibition mechanism of ITT and TEO at the molecular level. In addition, the adsorption behavior of ITT and TEO on the surface of X65 steel is consistent with Langmuir isotherm adsorption. The results of experimental and theoretical studies have shown that the inhibition effect of TEO is better than ITT for X65 in 0.5 M H 2 SO 4. [ABSTRACT FROM AUTHOR]

2-amino-6-bromobenzothiazole (ABBT) as an inhibitor of copper corrosion in 0.5 M H2SO4 solution was researched in this study using with electrochemical measurement, scanning electron microscope, atomic force microscope, and theoretical calculation. Polarization curves manifest that ABBT acts as a modest cathodic-type inhibitor with a maximum achievable inhibition efficiency of 94.6% at 1 mM. EIS test indicates that ABBT adsorb on the copper surface and form an adsorption film, which obeys Langmuir adsorption model. Furthermore, DFT calculation and molecular dynamics simulation were utilized to explore the mechanism of inhibition of ABBT. [ABSTRACT FROM AUTHOR]

[Display omitted] • The inhibitory effect of P1 and P2 tested reveal excellent protective qualities for protection of AA2024-T3 alloy against corrosion in in 3.5 wt% NaCl medium. • The adsorption characteristics of both P1 and P2 followed the Langmuir adsorption isotherm model. • MEB coupled with the EDX shows the existence of a stable and insoluble adherent deposit. • DFT calculations MD modeling revealed that both examined molecules could act as electrondonor/acceptor to/from the aluminum surface. This study's primary goal is to investigate how two heterocyclic chemicals block certain processes, namely nihydrine (2,2-dihydroxyindan-1,3-dione) (P1) and 2-Amino-3-phenylpropanoic acid (P2) against the degradation of AA2024_T3 in 3.5% NaCl solution utilizing Potentiodynamic Polarization (PDP) & Electrochemical Impedance Spectroscopy (EIS). The MEB/EDX allows for examining the morphology of the sample surface.The PDP and EIS analyses demonstrate that P1 and P2 function as cathodic-type corrosion inhibitors, with charge transfer and film formation mechanisms regulating the corrosion process, respectively. The inhibition efficiencies of P1 and P2 increase with concentration and reach a maximum at 10–2 M, with values of 89.1% (P1) and 96.3% (P2), respectively. The adsorption of P1 and P2 can be adequately characterized using the Langmuir adsorption isotherm. Furthermore, these inhibitors exhibit significantly higher activation thermodynamic characteristics compared to the blank. Results obtained from SEM/EDX analysis indicate that P1 and P2 may form a barrier layer by connecting to the AA2024-T3 alloy surface. In addition, DFT calculations and MD simulation models were performed to provide a more detailed understanding of the corrosion protection mechanism. [ABSTRACT FROM AUTHOR]

In this work, two indazole derivatives, namely 5-aminoindazole (AIA) and 5-nitroindazole (NIA), were investigated as corrosion inhibitors for carbon steel in 1 M HCl solution by experimental and density functional theory (DFT) methods. The electrochemical results indicate that the inhibition ability follows the order of AIA > NIA, which is due to the stronger electron-donating effect of –NH2 of the AIA group than the –NO2 group of NIA. Besides, the frontier orbital theory shows that the AIA exhibits higher reaction activity than NIA, and a more negative adsorption energy for AIA was also obtained, which is consistent with the analysis of the electrochemical measurements. We draw the conclusion that the electron-donating effect makes it easier for AIA to donate electrons to iron atoms to form a stronger protective layer than NIA. [ABSTRACT FROM AUTHOR]

Hot corrosion behavior of (Gd 0.9 Sc 0.1 ) 2 Zr 2 O 7 ceramic exposed to V 2 O 5 molten salt at 700–1000 °C was investigated, providing better understanding of its corrosion resistance as a promising thermal barrier coating. Obvious corrosion reaction occurred between (Gd 0.9 Sc 0.1 ) 2 Zr 2 O 7 and V 2 O 5 molten salt after 4 h heat treatment, corrosion products being temperature dependent. At 700 °C, large amount of Sc 2 O 3 doped ZrV 2 O 7 and GdVO 4 , together with a minor amount of Sc 2 O 3 -stabilized tetragonal ZrO 2 ( t -ZrO 2 ), formed on the sample surfaces. With the increase of the test temperature, Sc 2 O 3 doped ZrV 2 O 7 turned to decompose, leading to the formation of more t -ZrO 2 . At 900 °C and 1000 °C, the corrosion products were composed of GdVO 4 and t -ZrO 2 . The mechanism by which the corrosion reaction occurs is proposed based on phase diagrams and Lewis acid-base rule. [ABSTRACT FROM AUTHOR]

[Display omitted] • ANN and QSAR-base predictive models are used for design of ionic liquids based corrosion inhibitors. • Quantum chemical descriptors and inhibitor's concentration are used for MLR and ANN. • The MLPNN model displayed better predictive performance than the MLR model. • Designed corrosion inhibitors show an inhibition efficiency higher than 80%. The present study reports the quantum chemical studies and quantitative structure activity relationship (QSAR) modeling of thirty ionic liquids utilized as chemical additives to repress mild steel degradation in 1.0 M HCl. Five molecular descriptors obtained from standardization of calculated descriptors together with the inhibitor concentration were employed in model building. Multiple linear regression (MLR) and multilayer perceptron neural network (MLPNN) modeling were utilized in model construction. The optimal MLPNN model was developed using a network architecture of 6-3-5-1 with Levenberg-Marquardt as the learning algorithm. The model yielded an MSE of 29.9242, RMSE of 5.4703, MAD of 4.9628, MAPE of 5.7809, rMBE of 0.1202 and CoV of 0.0052. The MLPNN model displayed better predictive performance than the MLR model. Furthermore, developed models were applied to forecast the inhibition efficiencies of five novel ionic liquids. The theoretical inhibitors were found to be effective inhibitors of steel corrosion, showing over 80% inhibition efficiency. [ABSTRACT FROM AUTHOR]

The corrosion of low–carbon steel in aggressive alkaline–saline environments is a very large problem. Protecting low–carbon steel from corrosion in aggressive alkaline–saline solutions using green inhibitors is a very important task in industry. However, there are no studies related to low–carbon steel corrosion in aggressive alkaline–saline environments. Green type corrosion inhibitors are an interesting topic of research. However, currently, the studied type inhibitors are not efficient at low concentrations, and there are no studies on them in aggressive alkaline–saline environments in regard to steel corrosion. In this research work, a novel gossypol–indole modification (GIM) is introduced as a green corrosion inhibitor for low–carbon steel in an aggressive alkaline–saline environment. This inhibitor is a large, highly planar structural molecule that is more water soluble than other inhibitors. Its inhibition behavior is stable at high temperatures, and it contains a large number of electron–rich heteroatoms. All of these properties make it an excellent corrosion inhibitor. The inhibition performance of the novel gossypol–indole modification for low–carbon steel in 1 M NaOH + 1 M NaCl is fully characterized by thermodynamic, gravimetric, electrochemical frequency modulation (EFM), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), density functional theory (DFT), molecular dynamics (MD) simulations, scanning electron microscopy (SEM) and energy dispersive X–ray spectrometry (EDX) methods. The results confirm that the novel gossypol–indole modification is an excellent inhibitor, with a maximum inhibition efficiency of 96.01% at 100 mg/L and 0.112 mM. The adsorption behavior follows the Langmuir isotherm. Electrochemical studies have indicated that this modified is a mixed–type corrosion inhibitor, and the theoretical investigations correlate well with the experimental results. [Display omitted] • Gossypol–indole modification is green and powerful corrosion inhibitor. • The maximum inhibition efficiency of GIM was 96.01% at 100 mg/L/0.112 mM. • GIM is mixed–type corrosion inhibitor. • Corrosion–cathodic and –anodic activities of low–carbon steel in aggressive alkaline–saline environment are significantly blocked with GIM. [ABSTRACT FROM AUTHOR]

The corrosion of steel materials in alkaline-saline media is the largest problem in industry. Economical and environmentally friendly corrosion inhibitors are crucial for corrosion protection. The present work is the first to introduce a novel cucurbit[6]uril-based [3]rotaxane supramolecular ionic liquid (CB6-based [3]rotaxane) as a green and efficient corrosion inhibitor for the chemical industry. The correlation between the supramolecular ionic liquid system and inhibition behavior was studied first. The inhibition characteristics of CB6-based [3]rotaxane in 1 M OH– + 1 M Cl– solution were first fully investigated by thermodynamic, gravimetric, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), electrochemical noise (EN), cyclic voltammetry (CV), density functional theory (DFT), molecular dynamics (MD) simulation, scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDX) methods. The experimental results confirmed that CB6-based [3]rotaxane exhibited excellent corrosion resistance, and its inhibition efficiency was 97.97% at 100 mg/L and 0.032 mM. The electrochemical results suggested that (i) CB6-based [3]rotaxane was a mixed-type corrosion inhibitor with anodic dominance; (ii) the supramolecular part of selected ionic liquid is responsible for notably blocks the charge transfer process on the metal surface. The theoretical findings correlated well with the experimental results and revealed that the protonated form of this supramolecular structure exhibited better performance than its neutral form. MD simulations results suggested that the bond length of the Fe(surface)-inhibitor (3.127 Å) is less than 3.5 Å, which indicates that chemisorption is dominant in the investigated adsorption system. Molecular electrostatic potential analysis confirmed that the studied ionic liquid-supramolecular system contained most favorable nucleophilic centers, which are responsible for excellent inhibition performance. [Display omitted] • A novel cucurbit[6]uril-based [3]rotaxane (CU6R) was introduced for the first as a green and efficient corrosion inhibitor for the chemical industry. • Carbon steel inhibition in an aggressive alkaline-saline solution was studied with a CU6R for the first time. • The inhibition characteristics of CU6R in 1 M OH– + 1 M Cl– solution were fully studied. • The MD simulation findings that CU6R interacts well with the Fe(101) surface. [ABSTRACT FROM AUTHOR]

The corrosion of steel materials in alkaline-saline media is the largest problem in industry. Economical and environmentally friendly corrosion inhibitors are crucial for corrosion protection. The present work is the first to introduce a novel cucurbit[6]uril-based [3]rotaxane supramolecular ionic liquid (CB6-based [3]rotaxane) as a green and efficient corrosion inhibitor for the chemical industry. The correlation between the supramolecular ionic liquid system and inhibition behavior was studied first. The inhibition characteristics of CB6-based [3]rotaxane in 1 M OH– + 1 M Cl– solution were first fully investigated by thermodynamic, gravimetric, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), electrochemical noise (EN), cyclic voltammetry (CV), density functional theory (DFT), molecular dynamics (MD) simulation, scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDX) methods. The experimental results confirmed that CB6-based [3]rotaxane exhibited excellent corrosion resistance, and its inhibition efficiency was 97.97% at 100 mg/L and 0.032 mM. The electrochemical results suggested that (i) CB6-based [3]rotaxane was a mixed-type corrosion inhibitor with anodic dominance; (ii) the supramolecular part of selected ionic liquid is responsible for notably blocks the charge transfer process on the metal surface. The theoretical findings correlated well with the experimental results and revealed that the protonated form of this supramolecular structure exhibited better performance than its neutral form. MD simulations results suggested that the bond length of the Fe(surface)-inhibitor (3.127 Å) is less than 3.5 Å, which indicates that chemisorption is dominant in the investigated adsorption system. Molecular electrostatic potential analysis confirmed that the studied ionic liquid-supramolecular system contained most favorable nucleophilic centers, which are responsible for excellent inhibition performance. [Display omitted] • A novel cucurbit[6]uril-based [3]rotaxane (CU6R) was introduced for the first as a green and efficient corrosion inhibitor for the chemical industry. • Carbon steel inhibition in an aggressive alkaline-saline solution was studied with a CU6R for the first time. • The inhibition characteristics of CU6R in 1 M OH– + 1 M Cl– solution were fully studied. • The MD simulation findings that CU6R interacts well with the Fe(101) surface. [ABSTRACT FROM AUTHOR]

• A novel bromide–cucurbit[7]uril (BrCU) supramolecular ionic liquid was first introduced as a green corrosion inhibitor. • The maximum inhibition efficiency of BrCU was 97.54% at 100 mg/L/0.06 mM. • The obtained PDP data suggested that BrCU was a predominantly anodic mixed–type corrosion inhibitor. • Theoretical calculations support the experimental results. Metal corrosion is the largest problem in the oil and gas industry. Therefore, providing metallic materials with corrosion protection is an urgent task in modern research. The use of green corrosion inhibitors for corrosion protection is very important both ecologically and economically. This work is the first to introduce a novel bromide–cucurbit[7]uril (BrCU) supramolecular ionic liquid as an excellent corrosion inhibitor for the oil and gas industry. Its inhibition behaviour for carbon steel in 1 M NaCl saturated with CO 2 and H 2 S was first fully identified through the use of thermodynamic and gravimetric analysis, electrochemical noise (EN), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM), density functional theory (DFT), scanning electron microscopy (SEM) and energy dispersive X–ray spectroscopy (EDX) methods. The experimental results confirmed that BrCU is an excellent environmentally friendly corrosion inhibitor for the gas and oil industry. Its inhibition efficiency was 97.54% at 100 mg/L/0.06 mM, and it was more stable at high temperature (333 K). A Langmuir isotherm was applied to identify the adsorption character of BrCU on the metal surface. The obtained PDP data suggested that BrCU was a predominantly anodic mixed–type corrosion inhibitor. Theoretical calculations showed good correlation with the experimental results, indicating that the halogen modification in the supramolecular ionic liquid system improved the inhibition performance. [ABSTRACT FROM AUTHOR]

• Electrochemical tests were done on mild steel samples in 0.5 M sulfuric acid solution. • Maximum corrosion inhibition efficiency (>95%) was obtained with 500 mg/L. • Adsorption of phytochemicals was studied by DFT and MC simulations. • SEM and AFM verified the surface adsorption of P. somniferum. The corrosion resistance of iron alloy in 0.5 M sulphuric acid was checked in the presence and absence of Papaver somniferum (P. somniferum) seed extract. Notably, P. somniferum showed 95% corrosion resistance efficiency at 500 mg/L concentration. The adsorption of this inhibitor follows the Langmuir isotherm indicating its monolayer formation on the surface of iron alloy. The potentiodynamic experiments indicated its nature as mixed type of inhibition behaviour. The SEM and AFM techniques were used to study the protective layer on iron alloy. FT-IR with ATR confirmed various functional groups containing heteroatoms present in phytochemicals and formed complex with iron respectively. Theoretical studies were given as a valuable report to understand the comparative adsorption of phytochemical. All acquired outcomes confirmed that P. somniferum seed extract act as an efficient corrosion inhibitor. [ABSTRACT FROM AUTHOR]

• AFM analysis showed that the EPT could effectively block the acid attack by chemisorption on the carbon steel surface. • EPT epoxy polymer inhibitor employed showed higher inhibitory efficiencies at 10-3 [M] for EIS (95.02%), PDP (94.23%) and WL (92.49%) • DFT and MD simulations are in good agreement with experiments results. • All temperatures investigated show the adsorption energies are negative and therefore spontaneous adsorption can be expected. Novel derivative epoxy polymer such as 2,4,6-tris(4-(2-(4-(2-methoxy oxiran) phenyl) propan-2-yl) phenoxy)-1,3,5-triazine (EPT) was developed as investigated anticorrosive performance for carbon steel (CS) in [1 M] HCl medium. Moreover, the anticorrosive performance of EPT for CS in [1 M] HCl medium was employed using stationary (weight loss (WL)) and transient methods (electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP)), effect of temperature, adsorption isotherm, atomic force microscope (AFM), density functional theory (DFT) and molecular dynamics (MD) simulations. Then, EPT inhibitor polymer showed higher inhibitory efficiencies at 10-3 [M] for EIS, PDP and WL measurements are 95.02, 94.23 and 92.49, respectively. AFM analysis shows that the EPT epoxy polymer can be significantly stopped the acid attack by chemical adsorption on the area of the carbon steel. Further, EPT was identified using Fourier transform infrared (FTIR) spectroscopy. In addition, PDP characterization indicated that EPT inhibitor polymer acts as a mixed inhibitor and its adsorption of EPT obeyed Langmuir adsorption isotherm model. Also, all chemical descriptors obtained by DFT suggest that the EPT macromolecule is very well adsorbed by the adhesion centers on CS surface. The adsorption energies obtained by MD simulations for all temperatures investigated are negative and spontaneous adsorption could be expected. These computational approaches again support our experimental results and EPT could be used as potential inhibitor for carbon steel in [1 M] HCl medium. [ABSTRACT FROM AUTHOR]

• ACDs exhibited good efficiency in acidic solution. • Simulations showed excellent correlation with experimental data. • EFM showed potential mitigation of steel by ACDs at 600 mg/L. • SEM and AFM confirmed inhibitor/metal complex formation. Two new acridinedione namely 3,3,6,6-Tetramethyl-9,10-diphenyl-3,4,6,7,9,10-hexahydro-1,8-(2H,5H)-acridinedione (ACD-1), and 9-(4-methoxyphenyl)-3,3,6,6-tetramethyl-10-phenyl-3,4,6,7,9,10-hexahydroacridine-1,8(2H,5H)-dione (ACD-2) were synthesized and tested as prominent inhibitors for N80 steel corrosion inhibition in 15% hydrochloric acid (HCl). The weight loss result showed maximum efficiency of 97.3% (ACD-2) and Langmuir isotherm model best explained the adsorption of ACDs. EIS study reveals R ct value increased to a maximum of 816.4 Ωcm2 with the inhibition efficiency of 95.6% at 600 mg/L (ACD-2). The results of PDP proposed that ACDs are mixed but cathodic dominance inhibitors. The scanning electron microscopy (SEM) and atomic force microscopy (AFM) tests supports the adsorption of ACDs molecules onto the N80 steel surface. Intermolecular interactions and dynamics were studied using density functional theory (DFT) and molecular dynamics (MD). [ABSTRACT FROM AUTHOR]