Corrosion Inhibition Performance Research Articles

Electrochemical analysis of corrosion inhibition shallot leaf (Allium cepa) extract on mild steel in acidic medium at different immersion times

Plant derivatives as eco-friendly corrosion inhibitors are currently greatly interested in much research. Shallot leaf (Allium cepa) was utilized in 0.1M HCl as a corrosion inhibitor of mild steel. The functional groups present in the macerated extract were subsequently identified using an FTIR test. Electrochemical tests such as tafel polarization and EIS were carried out to determine the corrosion inhibition performance of shallot leaf extract on the SS400 steel. The results of the electrochemical analysis show that shallot leaf extract can inhibit mild steel up to 94% at a concentration of 500 ppm. Furthermore, the addition of SLE reduces surface damage of mild steel, which can be seen by SEM.

Gallic acid-infused LDH nano-containers: A durable protection against mild steel corrosion in simulated seawater

A novel low-dimensional composite nanoparticle is created by using magnesium/aluminum layered double hydroxide (Mg|Al LDH) as a carrier for Gallic acid (GA). The GA is then integrated into the LDH, forming LDH/GA, at varying ratios. These composite systems are then evaluated for their ability to prevent corrosion on steel substrates in a neutral 3.5 wt.% NaCl environment at different concentrations.To understand the structural changes, the chemical composition of GA, LDH, and the crystal structures of LDH/GA are examined using Fourier-transform infrared spectroscopy (FT-IR) and X-Ray diffraction (XRD) and Ultraviolet–visible (UV–Vis) tests. Also, the corrosion inhibition performance of these composite particles is assessed using Electrochemical impedance spectroscopy (EIS) and polarization tests, helping to elucidate the protective mechanism. The morphology of both corroded and protected substrates is visualized using Field Emission Scanning Electron Microscope (FE-SEM).EIS and polarization results indicate that the incorporation of 800 ppm GA into LDH significantly improves the corrosion inhibition performance, achieving up to 73 % and 78 % inhibition, respectively. Contact angle measurements reveal that the corroded samples exhibit hydrophilic characteristics, while the formation of a GA layer enhances their hydrophilicity. Increasing the concentrations of GA and LDH/GA also results in a higher degree of hydrophilicity.

Synthesis and application feasibility study of cetyltrimethylammonium p-toluenesulfonate

Abstract To improve the insufficient performance of anion on cationic surfactants and to further study the influence of anion on the surface properties, a cationic surfactant (cetyltrimethylammonium p-toluenesulfonate, CTATS) was prepared, and the relevant surface properties, including surface tension, critical micelle concentration, foaming ability and stability, corrosion inhibition and oil displacement efficiency were studied. Compared to cetyltrimethylammonium chloride (CTAC), CTATS exhibited higher surface activity, lower foaming volume, higher foam stability, higher corrosion inhibition performance and oil displacement efficiency. The results indicate that the CTATS has better performances as a surfactant type in oil and gas fields.

Study on an all-in-one foaming agent with corrosion inhibition for air foam flooding

Abstract Foam has been widely used in drilling, well washing, and oil driving during the development of oil and gas fields. Although air foams have been successfully employed as an enhanced oil medium, the oxygen they contain can seriously corrode piping systems, which can have a negative influence on output. This work used a combination of sodium dodecyl sulfate (SDS), dodecyl aminopropyl betaine (LAB), sodium dodecylbenzene sulfonate (SDBS), and cosurfactants to solve the problem above. The corrosion inhibitor hydrazine hydrate (N₂H₄·H₂O) was added as corrosion inhibitor. The foaming (air)-corrosion inhibitor all-in-one (SLN) was obtained with the formulation of SDS: LAB: N₂H₄·H₂O = 8:2:4. The foam volume of 0.7 % SLN was measured to be 515 mL at room temperature with a half-life of 4.1 min using the stirring method. The initial foam height of this all-in-one agent was measured to be 15.6 cm at 30 °C using the Roche foaming method. The foam height was still maintained at 15.5 cm after 20 min with a foam height retention of 99.2 %. The foam height retention rate was 50.0 % at 70 °C. Moreover, the formulation had good salt resistance to common inorganic salts in oilfield water. It should be emphasized that the SLN all-in-one agent has strong corrosion inhibition performance, and the corrosion inhibition rate can reach up to 96.9 %. The surface tension of this SLN all-in-one agent was reduced to 27.8 mN m−1 at a concentration of 0.1 %. It indicated that the all-in-one agent might increase the stability of the foam by decreasing the surface tension, thus improving the persistence of the foam and the effect of the repelling oil.

Electrochemical and surface analysis investigation of corrosion inhibition performance: 6-Thioguanine, benzotriazole, and phosphate salt on simulated patinas of bronze relics

Organic heterocyclic corrosion inhibitors play a crucial role in the non-destructive protection of excavated bronze relics exposed to the atmosphere. However, the current selection of corrosion inhibitors, additives, and dosage requires further investigation. This study involves a comprehensive preparation simulation of electrode materials and atmospheric corrosion electrolytes. The corrosion inhibition performance of 6-thioguanine (6-Tg) and traditional benzotriazole (BTA) inhibitors at pH = 7.5 is explored. Analytical techniques such as potentiodynamic polarization, EIS, XRD, XPS, and SEM-EDS were employed to analyze the characteristics of the research electrode materials. Surface analysis reveals that 6-Tg forms a protective corrosion inhibition film on the surface of the covered patina electrode, influencing the transition of Cu2(OH)3Cl to the more stable Cu2(OH)2CO3 crystal. Electrochemical results demonstrate that, after 600 h in the corrosion solution containing 0.1 g/L of 6-Tg, the corrosion potential and corrosion current reach 0.244 V and 4.9 μA cm−2, respectively. Upon adding 1.2 g/L of NaH2PO4, the polarization resistance and inhibiting efficiencies reach 15.6 kΩ cm2 and 99%, resulting in a synergistic corrosion inhibition effect and passivation potential shift from −0.6 V to 0.2 V region.

Corrosion inhibition alternatives and a novel chromate-like option: Review

Abstract Hexavalent chromium has dominated the corrosion inhibitor’s market as a benchmark alternative due to its unparalleled excellent corrosion inhibition properties. However, it was phased out because of its carcinogenic effects. Subsequently, many alternative inhibitors have been introduced into the inhibitor’s market but failed to meet the performance of this benchmark inhibitor. Recently, intelli-ion (AX1) was reported as a new alternative to hexavalent chromium based on Scanning Kelvin Probe (SKP) carried out on hot-dip galvanized steel (HDG) substrates for chromate and intelli-ion inhibitors. The intelli-ion system showed impressive performance at generation 1, with increased protection offered by the generation 2 product, showing no visible failure after 4 days test procedure. To further validate this, the cut edge corrosion performance of intelli-ion (AX1) and benzotriazole (BTA) was studied on galvanized steel specimen in 5wt.% NaCl solution using Scanning Vibrating Electrode Technique (SVET). From the SVET current density maps of AX1 (specimen A and B) vs. BTA (specimen C) after 24 h in 5 wt.% NaCl solution. The AX1 inhibitor had a better overall cut edge corrosion inhibition performance than the BTA.

Excellent corrosion inhibition and lubrication performance of MMT based ionic liquids as ester oil additives

In this work, electrochemical experiments and friction tests were conducted to investigate anti-corrosion properties and lubrication performance of the 2-mercapto-5-methyl thiadiazole (MMT) based ILs as additives of ester oil. The outcomes of electrochemical experiments were further supported by quantum chemical simulation which clarified the reason for corrosion inhibition from a microscopic perspective. Electrochemical impedance spectroscopy obtained from different temperatures (from 293 K to 323 K) showed that the inhibitors could reach a higher corrosion inhibition efficiency at 293 K. The experimental data exhibited that the adsorption behavior obeys Langmuir adsorption isotherm and the inhibitors adsorbed on the surface in a laying way seen from the results of theoretical simulation. Besides, SEM and XPS were employed to analyze the corrosion morphologies of immersion tests corroborating the presence of adsorption film on the steel surface. The tribological performance of MMT based ILs as base oil additives were examined by four-ball tester. The friction coefficient dropped by 47% and wear scar diameter decreased by 28% contrast to the base oil sample. The outstanding corrosion inhibition properties and friction-reducing and anti-wear performance could make it prospect for some industrial applications in energy saving.

Epoxy coating reinforced with graphene-PANI nanocomposites for enhancement of corrosion-resistance performance of mild steel in saline water

Protective coatings enriched with different types of chemical additives, functional fillers, and nanostructured materials are gaining immense interest to minimize corrosion. The present work demonstrates the synthesis of chemically functionalized reduced graphene oxide (rmGO) and emeraldine salt form of polyaniline (PANI-ES)-based rmGO-PANI-ES nanocomposites as protective functional fillers for epoxy coating to inhibit mild steel corrosion. The oxidative polymerization of aniline into PANI-ES is initiated on nitrogen-rich active sites of rmGO, and it propagates along the basal plane of rmGO, eventually enwrapped the graphene sheets by interfacially grown PANI-ES. The synthesis of rmGO-PANI-ES nanocomposites and their chemical, morphological, crystalline, and structural characteristics are examined by the FTIR, 13C NMR, XPS, XRD, Raman, SEM, and HRTEM analyses. The multiple interactions between the highly polar nitrogen-rich rmGO-PANI-ES nanocomposites and the epoxy matrix strengthened the coating and increased the hardness and elastic modulus. The corrosion inhibition performance of epoxy coating enriched with the rmGO-PANI-ES nanocomposites is probed by electrochemical impedance spectroscopic (EIS) and salt spray tests using an accelerated corrosive environment (3.5 wt% NaCl). The rmGO-PANI-ES-15 nanocomposite having 0.15 wt% rGO in epoxy coating showed superior corrosion inhibition performance. The total electrochemical impedance of epoxy coating (8.7 ×103 Ω.cm2) increased to 4.7 ×1015 Ω.cm2 after incorporating 1 wt% rmGO-PANI-ES-15 nanocomposite. The enhancement of electrochemical impedance by ∼12 orders of magnitude demonstrates the effectiveness of the rmGO-PANI-ES nanocomposites for corrosion mitigation in a harsh corrosive environment. The high surface area and remarkable structural barrier of the 2D chemically functionalized graphene furnished excellent protective coverage. The PANI-ES of rmGO-PANI-ES nanocomposites formed a passive layer of fully reduced leucoemeraldine base of PANI (PANI-LEB) on the coating-mild steel interface by accepting the electrons, generated during the anodic oxidation of iron. These events collectively increase the impedance by multifolds and inhibit steel corrosion. The present findings revealed that graphene-enriched conductive polymeric nanocomposites-based coatings can be promising solution to mitigate corrosion of metal-based installations in a marine environment.

Effect of brine salinity on the partitioning, distribution and corrosion inhibition performance of a quaternary amine corrosion inhibitor

Surfactant corrosion inhibition performance in water–oil environments is influenced by complex relationships between their physical properties, solution chemistry and interfacial characteristics. The existence of polar heads/nonpolar tails influences both the preferential distribution of the surfactant between the two media as well as the phase in which micellisation occurs. Both phenomena affect the efficiency of the surfactant inhibitor and its adsorption at the metal-solution interface. To demonstrate the complexity of such interactions, the effect of brine salinity on the critical micelle concentration (CMC) and partitioning/distribution behaviour of a quaternary amine corrosion inhibitor (alkyldimethylbenzylhexadecylammonium chloride, or BAC-C16) in a brine and toluene system (at 1:1 ratio) was explored. All experiments were conducted at 50 °C and pH4 over varying salinities (0.1, 1 and 10 wt%) of NaCl brine. Both CMC and partitioning characteristics of BAC-C16 are significantly affected by aqueous phase salinity, with an inversion of the partitioning response observed between concentrations of 0.1 and 1 wt% NaCl. The effect of BAC-C16 partitioning/distribution behaviour on corrosion inhibitor performance was examined using rotating cylinder electrode experiments. The results illustrate that in order to establish the true corrosion inhibition behaviour, consideration of the chemical distribution characteristics is crucial.

Elucidating the mechanisms of novel thiazole-based corrosion inhibitors in carbon steel/HCl interface: An integrated approach combining experimental and computational studies

Corrosion inhibitors serve as a paramount strategy in the domain of metal protection. This study investigates the efficacy of two thiazole derivatives, namely methyl (E)-5-(4-chlorophenyl)-2-((2-(1-hydroxynaphthalen-2-yl)vinyl)amino)thiazole-4-carboxylate (ThN), and methyl (E)-5-(4-chlorophenyl)-2-((2-hydroxystyryl)amino)thiazole-4-carboxylate (ThP) in mitigating corrosion of carbon steel in a 1 mol/L hydrochloric acid medium. Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization (PDP), Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (SEM-EDX), and X-ray Diffraction analysis (XRD) were used to experimentally assess the corrosion inhibition performance of compounds under study. Experimental results revealed a concentration-dependent increase in the corrosion inhibition efficiencies of the thiazole derivatives, with ThP achieving 90 % and ThN attaining 93 %. The adsorption of both compounds adhered to the Langmuir adsorption model, indicating a physicochemical inhibition mechanism. PDP analyses revealed a mixed-type inhibitory behavior. Furthermore, SEM-EDX assessments validated the ability of the thiazole derivatives to enhance corrosion resistance. XRD studies revealed a marked decrease in corrosion-associated peaks upon the introduction of thiazole derivatives. The potential of zero charge (PZC) for the carbon steel was ascertained via EIS, clarifying the adsorption mechanism. Employing Conductor like Screening Model for Realistic Solvents (COSMO-RS), the solvation properties of the compounds were evaluated, while Quantum Chemical Calculations (QCCs) and Molecular Dynamics (MD) simulations contributed insights into reactivity descriptors and adsorption configurations on the Fe(110) surface. This study highlighted the impact of the aryl group on the adsorption and corrosion inhibition characteristics of investigated compounds, offering valuable guidance for future design and development.

Inhibition performance of extract reinforcement corrosion inhibitor from waste Platanus acerifolia leaves in simulated concrete pore solution

In our previous study, the ultrasound-assisted enzymatic extract of Platanus acerifolia leaves (PAL) was confirmed as an efficient corrosion inhibitor of steel. In this study, a new strategy-ultrafiltration-was proposed to further enhance the corrosion inhibition effect of this green steel corrosion inhibitor. To pinpoint the main players in the corrosion-inhibiting performance, the active compounds of the treated PAL extract were further quantitatively characterized via high performance liquid chromatography (HPLC). Electrochemical approaches were employed to investigate the anti-corrosion behavior. The adsorption film and surface morphology of the steel surface were characterized via X-ray photoelectron spectroscopy (XPS) and scanning electron microscope with energy dispersive spectrometer (SEM-EDS), respectively. Furthermore, simulations were carried out to further explore the inhibition mechanisms of the active molecules. The results showed that ultrafiltration significantly removed the polysaccharide impurities, thereby further concentrating the inhibition constituents. Twelve flavonoids and their derivatives were quantitatively traced, among which the procyanidins was the most pronounced ingredient (220 ppm). Ultrafiltration can effectively improve the inhibition performance of the extract. In the presence of chloride ions, the inhibition efficiency of the 1.5 wt% two-step processed extract was equivalent to that of the 5 wt% primary extract. Plus, SEM-EDS observations confirmed that the two-step processed extract was able to effectively mitigate the corrosion degree. XPS and simulation analyses revealed that the flavonoids and their derivatives executed the corrosion inhibition performance by forming a protective carbon-containing organic film on the steel surface via chelation and surface physical adsorption.

Corrosion inhibition performance of copper using N-benzylhy-drazinecarbothioamide in a 3.5 % NaCl solution

In this report, N-benzylhydrazinecarbothioamide (BHCTA) was investigated as an organic inhibitor for the corrosion of copper substrate in 3.5 wt.% sodium chloride electrolyte at 298 K. The inhibition efficiency of BHCTA was examined using electrochemical, chemical and theoretical tools. The gained outcomes indicated a supreme inhibition efficiency of BHCTA which exceeded 95 % upon addition of 1.00 mM of BHCTA. Such supreme efficiency was discussed on the basis of decisive adsorption of BHCTA molecules on the copper substrate that hinders concurrently the anodic oxidation and cathodic reduction reactions progressions. The adsorption of BHCTA on the copper surface was discovered to obey Langmuir isotherm. The resulting value of DGads0 = −35.7 kJ mol−1 indicates that BHCTA molecules adsorb on the copper surface through a spontaneous mix of physisorption and chemisorption processes. A scanning electron microscope was used to examine the effect of BHCTA adsorption on the morphology of the copper surface. Theoretical calculations showed that BHCTA has good adsorption properties on Cu substrate. There is a good consistency between the applied experimental and theoretical tools, confirming the validity of the gained outcomes.

Revealing the Deterioration Effect of Scale Inhibitor on the Performance of Corrosion Inhibitor under Dynamic Conditions

Revealing the Deterioration Effect of Scale Inhibitor on the Performance of Corrosion Inhibitor under Dynamic Conditions

Anticorrosion evaluation of novel Schiff-Imidazole molecules for Q235 steel in 1.0 mol/L HCl by computational and experimental methodologies

This manuscript synthesized successfully two efficient imidazole-Schiff derivatives (FMIX and MIX), and confirmed the structural rationality through infrared spectroscopy (IR), nuclear magnetic resonance(NMR) and elemental analysis, and the corrosion inhibition performance and mechanism in 1.0 mol/L HCl were investigated. The weight loss experiment showed that at 2.0 mmol/L and the corrosion inhibition efficiency of FMIX and MIX were 97.39 % and 98.52 %, respectively, indicating that this corrosion inhibitor has excellent corrosion inhibition performance. The open circuit potential (OCP) and potentiodynamic polarization curve (Tafel) indicated that FMIX and MIX belong to cathodic corrosion inhibitors. Electrochemical impedance spectroscopy (EIS) shown that FMIX and MIX increased the film resistance and charge transfer resistance in the corrosion solution, and adsorbed on the surface of Q235 to form a stable protective film. XPS, EDS, and IR tests have shown that FMIX and MIX could adsorb on the surface of Q235 to form a stable protective film, thereby inhibiting the occurrence of corrosion. Density functional theory (DFT) and molecular dynamics simulation (MD) have also confirmed at the molecular level that FMIX and MIX could spontaneously adsorb on the surface of Q235 and form a stable protective film.

Enhancing the corrosion inhibition performance of Mannich base on mild steel in lactic acid solution through synergistic effect of allicin: Experimental and theoretical study

Protonated Mannich base N,N′-bis(3-oxo-3-phenylpropyl)ethane-1,2-diamine dihydrochloride (EDAM) was synthesized and its chemical structure was characterized by means of 1H NMR, 13C NMR, Fourier-transform infrared spectroscopy (FTIR) and elemental analysis. The synergistic inhibitive effect of EDAM with allicin on N80 steel in 15 % lactic acid solution at 363 K was investigated using weight loss experiments, electrochemical tests, and surface analysis techniques (including scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS), and contact angle measurement), quantum chemical calculation and molecular dynamics (MD) simulation methods. The results show that the inhibition performance was significantly improved by combining EDAM and allicin. The inhibition efficacy (IE) reached 99.60 % at the mass ratio of 10:1 (EDAM/allicin) with total inhibitor dosage of 0.1 %. Electrochemical impedance test (EIS) proves that the charge transfer-controlled corrosion process is greatly hindered with the addition of allicin. The small changes in the corrosion potential of Tafel curves indicate that the complex system is a hybrid corrosion inhibition mechanism. SEM, AFM, XPS and contact angle surface analyses suggest that EDAM in cooperation with allicin forms a dense and strongly adsorbed protective film on the metal surface. The density functional theory (DFT) and molecular dynamics simulation (MD) calculations further elucidate the mechanism of the synergistic corrosion inhibition effect.

Computational, theoretical and experimental studies of four amino acids as corrosion inhibitors for brass in 3% NaCl medium

The corrosion inhibition performance of some amino acids such as L-cysteine (L-cys), L-methionine (L-met), L-tyrosine (L-tyr), and L-histidine (L-his) as environmentally safe corrosion inhibitors for brass in aerated and stirred 3 % NaCl solution was studied by Potentiodynamic Polarization and impedance measurements. Cys showed better corrosion inhibition efficiency (88 %) and prevented the formation of corrosion products responsible for the corrosion of brass. Protonated cysteine demonstrated a high corrosion inhibition performance by providing strong interactions between the lone pairs of its sulfur and nitrogen atoms and the vacant d-orbitals of copper atoms. Corrosion products and the protective layer were analyzed using SEM-EDS techniques. Molecular structures of the four studied amino acids have been geometrically optimized by DFT/ B3LYP method, with the function 6–311++G(d, p). Molecular electrostatic potential (MEP) and Mulliken charge analysis were used to predict the adsorption sites of the studied amino acids. Some confusing electronic parameters have been resolved using non-covalent interactions (NCI) method, which revealed the presence of intramolecular interactions and steric hindrance at the molecular level. Conformational analysis using Monte Carlo (MC) simulations method was performed in order to give better insight into the adsorption mechanism of the protonated cysteine on the metal surface via its thiol and amino groups.

Corrosion inhibition mechanisms of triazole derivatives on copper chemical mechanical polishing: Combined experiment and DFT study

The impact of triazole derivative groups on corrosion inhibition performance of copper (Cu) film is studied by using 3-amino-1,2,4-triazole-5-carboxylicacid (ATA-O), 1H-1,2,4-triazole-3,5-diamine (ATA-N) and 3-amino-5-mercapto-1,2,4-triazole (ATA-S) as environment-friendly inhibitors. Electrochemical analysis showed that anti-corrosion passivation layer is formed on Cu surface after adding inhibitors with high inhibition efficiency of 54 %, 87 % and 98 % respectively, and improve the surface quality which is verified by atomic force microscope (AFM) and scanning electron microscopy (SEM) tests. Such results are consisted with static etch experiments. The mechanism of corrosion inhibition was revealed by theoretical calculation, which prove that the lone electron pair in empty orbitals of the O, N, S atoms on inhibitors hybridize with the Cu-d orbital to form covalent bonds and enhance the adsorption passivation action. Such study dissects the reasons for the potent inhibitory effect of triazole derivatives at the atomic level, and provides new method for efficient selection of inhibitors.

Smart release of turmeric as a potential corrosion inhibitor from a pH-responsive polymer encapsulated highly ordered mesoporous silica containers

This study reports on the loading of corrosion inhibitors like benzotriazole (organic), tartrazine, and turmeric (green) into highly ordered mesoporous silica containers encapsulated with a pH-responsive polymer poly(diallyldimethylammonium chloride) (PDDA) for the smart and sustained release. The incorporation and encapsulation of green corrosion inhibitors, release kinetics and its inhibition efficiency is not studied yet. The synthesised containers had a mesoporous micro-rod-like structure with a pore size of 7 nm and a high surface area of 514.26 m2/g. The pH-responsive behaviour of the PDDA encapsulating polymer is confirmed by monitoring the release of the inhibitors in neutral and alkaline solutions using UV–Visible spectroscopy. The corrosion inhibition performance and its mechanism are evaluated in an alkaline environment containing 0.1 M NaCl using electrochemical impedance spectroscopy over a period of 168 h on mild steel. Among the studied corrosion inhibitors, turmeric showed a maximum of 85.4 % inhibition efficiency after 1 h of immersion. However, SBA-15-Turmeric-PDDA exhibited a higher Rp value of 0.96 kΩ cm2 compared to only turmeric after 168 h of exposure. The smart release of turmeric and silica adsorption showed enhanced corrosion protection, which can be used for various industrial applications.

Adsorption behavior and corrosion inhibition performance of tetrazolium derivatives on electrolytic copper foil surface

The development of chromate-based post-treatment methods has been limited mainly due to their toxicity, thus it is essential to explore environmentally friendly corrosion inhibitors for electrolytic copper foil. Herein, we evaluated three tetrazolium compounds (tetrazolium, 5-methyl-tetrazolium, and 5-amino-tetrazolium) as potential corrosion inhibitors for electrolytic copper foil, and explored their adsorption behavior onto the copper foil surface and their efficiency in inhibiting corrosion when exposed to a 3.5 wt% NaCl solution. Density functional theory calculations provide insights into the relationship between the molecular structure of the inhibitors and their corrosion inhibition efficiency. Furthermore, molecular dynamics simulations elucidate the adsorption behavior of these inhibitors on copper surfaces under solvation conditions. Notably, the 5-amino-tetrazolium molecule exhibits the most stable chemisorption on the Cu(111) surface. Finally, both electrochemical tests and antioxidation experiments confirm that ATZ is the most effective corrosion inhibitor with a corrosion inhibition efficiency (η) of 93.09%, consistent with theoretical predictions. This study highlights the potential application of the tetrazolium derivative 5-amino-tetrazolium in environmentally friendly and chromium-free post-treatment of electrolytic copper foil surfaces.

Inhibition performances of new pyrazole derivatives against the corrosion of C38 steel in acidic medium: Computational study

Corrosion inhibition performances of two new pyrazole derivatives, namely 5-(4-dimethylamino)phenyl)-3-(4-dimethylamino)styryl)-4,5-dihydro-1H-pyrazole-1-carbothio amide (P1) and 5-(4-dimethylamino)phenyl)-3-phenyl-4,5-dihydro-1H-pyrazole-1-carbothio amide (P2) against the corrosion of carbon steel in acidic medium are theoretically investigated by combination of the density functional theory with the molecular dynamics approach. Additionally, the toxicity and solubility of the aforementioned molecules were investigated. Quantum chemical parameters of considered molecules (calculated energy levels of HOMO and LUMO molecular orbitals as well as the gap between them, hardness, softness, chemical potential, electronegativity, electrophilicity index, nucleophilicity, electro donating power, electro accepting power, polarizability, dipole moment, metal-inhibitor interaction energy, the fraction of electrons transferred from inhibitors to metal surface, back-donation energy, Fukui indices) were calculated at B3LYP/SVP, CAM-B3lyp/TZVP and ωB97XD/Def2-TZVP levels of theory. Comparative calculations were performed in the gaseous phase and in the aqueous solutions. The adsorption behavior of the mentioned molecules on the Fe (110) surface was investigated with the molecular dynamics. Both considered molecules demonstrates high adsorption energies on steel surface, low toxicity and high solubility. P1 is found to be more efficient in hydrochloric acid, whereas P2 molecule is found to be more efficient in sulfuric acid.