Corrosion inhibition of mild steel by Nettle (Urtica dioica L.) extract: polarization,EIS, AFM,SEM and EDS studies

Inhibitory action of Nettle (Urtica dioica L.) extract was investigated in hydrochloric acid solution through electrochemical (polarization, EIS) and surface analysis (optical microscopy/AFM/SEM/EDS) techniques. Effect of inhibitor concentration and temperature were evaluated. Thermodynamic parameters have been calculated and adsorption studies have been investigated. The electrochemical studies showed that NE inhibitor retards both cathodic and anodic processes through the inhibitor adsorption on the metal surface and blocking the active corrosion sites. A good fit to Langmuir adsorption isotherm was obtained between surface coverage degree and inhibitor concentration. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to characterize the microstructure and the nature of the metal surface. SEM and AFM images and energy dispersion spectrometer analysis for mild steel specimens in the absence and presence of the NE inhibitor confirmed the protective layer formation on the metal surface and proved the results obtained by the electrochemical experiments. Inhibition efficiency up to 92.24% has been achieved in 1?M acid solution containing 0.3?g/l inhibitor at 40?°C.     

1-(2-Hydroxyethyl)-2-imidazolidinone as corrosion inhibitor of mild steel in 0.5 M HCl solution: thermodynamic,electrochemical and theoretical studies

The inhibition effect of 1-(2-Hydroxyethyl)-2-imidazolidinone (2-HEI) on mild steel (MS) corrosion in 0.5?M HCl solution was investigated at different inhibitor concentration and temperature by electrochemical experiments, such as linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and quantum chemical calculations. The inhibitor adsorption process on mild steel in 0.5?M HCl system was studied at different temperatures (20?°C–50?°C). Furthermore, the surface morphology of MS was also investigated with SEM in the absence and the presence of inhibitor. The adsorption of 1-(2-Hydroxyethyl)-2-imidazolidinone on MS surface is an exothermic process and this process obeys the Langmuir adsorption isotherm. The Quantum chemical findings are good agreed with the empirical data.     

Investigation of corrosion inhibitory effect of hydroxyl propyl alginate on mild steel in acidic media

The anti‐corrosion effect of hydroxyl propyl alginate (HPA) on mild steel in 1M HCl has been studied by chemical (weight loss) and electrochemical (polarization and electrochemical impedance spectroscopy) methods. From all the three methods, it is inferred that there is an increase in inhibition efficiency with increase in concentration of the inhibitor. Polarization studies revealed the mixed mode of inhibition by HPA. The mode of adsorption is physical in nature. The adsorption of HPA on mild steel followed Frumkin adsorption isotherm. The thermodynamic and kinetic parameters have been calculated and discussed. Surface morphological studies have been carried out with Scanning electron microscopy (SEM) and Atomic force microscopy (AFM). Fourier transform infrared spectroscopy (FTIR) is utilized to characterize the adsorbed film. SEM and AFM methods confirm the presence of inhibitor on the surface of the metal. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43004.     

CHAMOMILE (Matricaria recutita) EXTRACT AS A CORROSION INHIBITOR FOR MILD STEEL IN HYDROCHLORIC ACID SOLUTION

The corrosion inhibition of mild steel in hydrochloric acid solution by chamomile (Matricaria recutita) extract (CE) was investigated through electrochemical (polarization, EIS) and surface analysis (optical microscopy/AFM/SEM) techniques. The effects of inhibitor concentration, temperature, and pH were evaluated. Thermodynamic parameters were calculated and adsorption studies were carried out. Finally, the surface morphology was investigated. The electrochemical studies showed that CE acts as a mixed-type corrosion inhibitor with predominantly anodic behavior. CE was adsorbed physically on the metal surface and obeyed the Langmuir adsorption isotherm. It impeded the corrosion processes by changing the activation energy. In the presence of CE, the metal surface was more uniform than the surface in the absence of inhibitor. Maximum inhibition efficiency (IE) was 93.28%, which was obtained at 22°C in 7.2 g/L of inhibitor in 1 M HCl solution.     

Experimental and theoretical study on amino acid derivatives as eco-friendly corrosion inhibitor on mild steel in hydrochloric acid solution

Amino acid derivatives, namely, 2-(2-oxo-2-phenothiazin-10-yl)ethylamino)-3-mercaptopropanoic acid (OPEM) and 2-(2-oxo-2-phenothiazin-10-yl)ethylamino)acetic acid (OPEA) were synthesized and investigated as inhibitors for mild steel corrosion in 15% HCl solution using the weight loss, polarization, and electrochemical impedance spectroscopy (EIS) techniques. The inhibition efficiency of both the inhibitors increased with increasing the temperature and concentration of inhibitor. The inhibitors OPEM and OPEA show corrosion inhibition efficiency of 97.5 and 95.8%, respectively, in 200?ppm concentration, at 333?K. Polarization studies showed that both studied inhibitors were of mixed type in nature. The adsorption of inhibitors on the mild steel surface obeys Langmuir adsorption isotherm and the surface of inhibited and uninhibited specimens were analyzed by scanning electron microscopy (SEM). The semiempirical AM1 method was employed for theoretical calculations and the obtained results were found to be consistent with the experimental findings.     

In depth analysis of anti corrosion behaviour of eco friendly gum exudate for mild steel in sulphuric acid medium

The current research work was keen to examine the corrosion inhibition efficiency of mild steel (MS) in presence of aqueous extract of Araucaria heterophylla Gum (AHG) in 1?M H₂SO₄ medium. The phytoconstituents of the AHG were interpreted by GC-MS and corrosion inhibition efficiency was deduced using other techniques like weight loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS). Adsorption of inhibitor molecules on the mild steel surface was supported by Density Functional Theory (DFT) studies, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). It is seen from the results that the inhibitor exhibits optimum efficiency of 78.57% at 0.05% v/v on mild steel specimen in 1?M H₂SO₄ medium at room temperature. Tafel polarizations clearly show that the aqueous extract of AHG acts as a mixed type inhibitor. The change in the EIS parameters in presence of inhibitor is investigative of the protective layer formation of the mild steel surface. The adsorption is found to obey Langmuir adsorption isotherm. Thermodynamic and activation parameters for the corrosion inhibition process supported the physical adsorption mechanism.     

Extraction and experimental studies of Citrus aurantifolia as an economical and green corrosion inhibitor for mild steel in acidic media

The Citrus aurantifolia leaves extract was tested for corrosion inhibition on the mild steel in a 0.5?M sulfuric acid solution using weight loss, Tafel and EIS. The state of mixed adsorption with the potentiodynamic polarization effect is shown. Citrus aurantifolia showed the strongest corrosion inhibition of 96.46% at a concentration of 250?mg/L. SEM and AFM are used to verify the formation of a protective layer on the surface of mild steel. The adsorption phenomenon was verified using UV-Vis. spectroscopic technique, whereas FT-IR confirmed the presence of several functional groups containing heteroatoms. Adsorption of the inhibitory molecules on the mild steel surface followed the Langmuir adsorption isotherm. All obtained results ensure that C. aurantifolia leaves extract can form an effective blocking layer and control the corrosion process.     

Corrosion inhibition of mild steel in 1 M HCl using Tamarindus indica extract: electrochemical,surface and spectroscopic studies

Abstract

We report, here, the corrosion inhibition of mild steel specimen in 1?M HCl by tamarind fruit pulp aqueous (TFPA) extract. The inhibition property in the presence of TFPA extract is studied using weight loss, polarization measurement and electrochemical impedance spectroscopy (EIS). The inhibitor efficiency is found to vary from 74% to 88% (weight loss method) with TFPA concentration of 100–600?ppm. The reduction in Tafel slopes shows that TFPA acts as a mixed-type inhibitor. The adsorption of the inhibitor on the metal surface follows Langmuir isotherm. The standard Gibbs free energy of adsorption value of –40?kJ/mol suggests the chemisorption of inhibitor molecules via coordinate bond. AFM results exhibit a decrease in the surface roughness of mild steel, exposed to 1?M HCl from 299?±?12 to 154?±?6.6?nm, with increasing concentration of inhibitor from 0 to 600?ppm due to the uniform coverage of inhibitor molecules on the metal surface. X-ray photoelectron spectroscopy de-convoluted high resolution profiles of C 1?s (carbon) for mild steel exposed to 1?M HCl with 600?ppm inhibitor show major peaks corresponding to sp³ C–C/C–H (284.9?eV) and oxygen bondings in C–OH, C=O, COOH with a binding energy of 285.9, 286.9, 288.5?eV, respectively, thereby confirming the adsorption of organic moieties on mild steel surface. Fourier transform infrared spectroscopy further confirms the adsorption of inhibitor molecules on the metal surface. Therefore, tamarind fruit pulp extract is a potential corrosion inhibitor for mild steel, which is cost-effective, green and non-toxic.     

Chitosan Schiff base as effective corrosion inhibitor for mild steel in acid medium

An environment friendly inhibitor, chitosan thiophene carboxaldehyde Schiff base, was synthesized by a condensation reaction of the carbonyl group of thiophene 2‐carboxaldehyde and free amino groups of chitosan. The chitosan Schiff base was characterized by UV spectroscopy, Fourier transform IR spectroscopy, elemental analysis and thermal analysis. The surface morphology of the Schiff base derivative was examined by SEM. Gravimetric and electrochemical techniques were used to explore the behaviour of the chitosan thiophene derivative as a corrosion inhibitor for mild steel in an acidic environment. The effects of inhibitor concentration, exposure time and temperature were investigated. The chitosan Schiff base showed a good inhibition performance of 92% inhibition efficiency at room temperature for 12 h of immersion in a weight loss experiment. The electrochemical results showed that the chitosan derivative acts as an effective mixed type inhibitor. The adsorption of the inhibitor followed the Temkin isotherm model. SEM and AFM techniques were used to characterize the protective layer formed on the mild steel substrate. © 2016 Society of Chemical Industry     

Investigation of some oleochemicals as green inhibitors on mild steel corrosion in sulfuric acid

The inhibitive effect of four oleo chemicals (namely; 2-Pentadecyl-1,3-imidazoline (PDI), 2-Undecyl-1,3-imidazoline (UDI), 2-Heptadecyl-1,3-imidazoline (HDI), 2-Nonyl-1,3-imidazoline (NI)), regarded as green inhibitors, were studied for the corrosion protection of mild steel in 0.5 M H₂SO₄. The methods employed were weight loss, potentiodynamic polarization and electrochemical impedance techniques. Scanning electron microscopy (SEM) was carried out on the inhibited and uninhibited metal samples to characterize the surface. The purity of synthesized inhibitors was checked by FT-IR and NMR studies. The inhibition efficiency increased with increase in inhibitor concentration, immersion time and decreased with increase in solution temperature. No significant change in IE values was observed with increase in acid concentration. The best performance was obtained for UDI possessing 96.2% inhibition efficiency at 500 ppm concentration. The adsorption of the compounds on the mild steel surface in the presence of sulfuric acid obeyed Langmuir’s adsorption isotherm. The values obtained for free energy of adsorption and heats of adsorption suggest physical adsorption. The addition of inhibitor decreased the entropy of activation suggesting that the inhibitors are more orderly arranged along the mild steel surface. The potentiodynamic polarization data indicate mixed control. The electrochemical impedance study further confirms the formation of a protective layer on the mild steel surface through the inhibitor adsorption.     

Theoretical and experimental studies of dried marjoram leaves extract as green inhibitor for corrosion protection of steel substrate in acidic solution

Dried marjoram leaves (DML) aqueous extract solution was prepared and characterized by Fourier transform infrared spectroscopy (FTIR) and cyclic voltammetry (CV). The effect of DML solution concentration on corrosion protection of mild steel in 0.5?M H₂SO₄ at different temperatures was studied using anodic and cathodic polarization and electrochemical impedance spectroscopy (EIS) measurements. It was determined from the polariazation curves that the DML acts as a mixed type inhibitor since, both the cathodic and anodic reactions of mild steel corrosion were inhibited. The protection efficiency increases with increasing concentration of DML and decreasing temperatures. The surface morphology was investigated before and after adsorption of DML molecules on the steel surface using scanning electron microscope (SEM). The activation and adsorption parameters were calculated and discussed. The results were supported using density functional theory (DFT), and the quantum chemical parameters were estimated. These parameters reveal the effect of the electronic structure of Thymol, the main component of DML, on its electron donating ability at the B3LYP/6-311?+?G (d, p) level.     

Aminothiazolyl coumarin derivatives as effectual inhibitors to alleviate corrosion on mild steel in 0.5 M H2SO4

To diminish corrosion which leads to structural damages and to implement a green mitigator has induced the usage of aminothiazolyl coumarin derivatives to study mild steel (MS) corrosion using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), weight loss, atomic force microscopy (AFM), and electron microscopy with energy dispersive spectroscopy (SEM–EDS) spectrometry in acid medium. The results showed that the inhibition efficiency was 90.8% for the least effective inhibitor and 97.1% for the most effective inhibitor at optimal concentration (10 mM). Enhancement of inhibition efficiency in weight loss method and increase in R_p values in impedance and mixed nature of the inhibition in polarization measurement reveals the best inhibition capacity of coumarins over the MS. The coumarins were characterized using FT-IR, NMR and Mass spectroscopy. The adsorption was well fitted with the Langmuir adsorption isotherm model. SEM–EDS and AFM images confirmed the shielding effect of coumarin derivatives through a layer formation on MS against acid medium. The adsorption mechanism of aminothiazolyl coumarin derivatives was further explored by quantum chemical calculations (DFT) and molecular dynamics (MD).

Graphic abstract

     

Synthesis and corrosion inhibition evaluation of a new schiff base hydrazone for mild steel corrosion in HCl medium: electrochemical,DFT, and molecular dynamics simulations studies

Abstract

The development of cost-effective, sustainable, eco-friendly and efficient compounds is a renovated science and a demanding assignment for today’s chemists and technology specialists. In this context, the anticorrosion effect of a new Schiff base hydrazone, namely (E)-2-(4-(2-(methyl(pyridin-2-yl)amino)ethoxy)benzylidiene)hydrazine-1-carboxamide (MPAH) against the mild steel (MS) surface in 1.0?M HCl has been analyzed utilizing experimental methods, thermodynamic characterizations, and computational studies. MPAH has proven to be an effective inhibitor in 1.0?M HCl solution. Its inhibition performance improved by raising the concentration of the compound to an optimal concentration of 5?×?10^?3 M, and 97% efficiency was achieved at 303?K. Inhibitor adsorption on the MS has been explicated with both physical and chemical interactions. The adsorption was in accordance with the isotherm of Langmuir. The impact of MPAH on the surface of MS had been confirmed utilizing SEM/EDX, electrochemical impedance spectroscopy (EIS), gravimetric measurements (WL), and potentiodynamic polarization (PDP). The adsorption of the studied compound on the MS surface has also been investigated by DFT and the molecular dynamics (MD) simulations.     

Study on the effect of vanillin on the corrosion inhibition of aluminum alloy

The effect of vanillin on the corrosion inhibition of aluminum (Al) alloy in seawater was studied by potentiodynamic polarization (PP), linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) techniques. The surface morphology after its exposure to seawater with and without vanillin was examined by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). All the studied parameters showed good inhibitive characteristics against the corrosion of Al alloy in the tested solution, and their performance was observed to increase with the inhibitor concentration. Polarization data indicated that the studied inhibitor is a mixed-type inhibitor. Linear polarization and EIS studies showed that there were significant increases in the overall resistance after the addition of vanillin. The adsorption of inhibitor on Al alloy was found to obey the Langmuir adsorption isotherm. The analysis of SEM and EDS confirmed the formation of precipitates of vanillin on the metal surface, which reduced the overall corrosion reaction.     

Chemical components of mature areca nut husk extract as a potential corrosion inhibitor for mild steel and copper in both acid and alkali media

Mature areca nut husk (MAH) extract was tested for its efficacy anticorrosive property at electrode–electrolyte interface through chemical and electrochemical techniques. Results of weight loss study show that maximum inhibition action of MAH extracts for copper and mild steel in both acid and alkali media was observed at 303?K with the contact time of 1 hour (94.347% for mild steel in 0.5?M HCl medium, 91.666% for mild steel in 0.5?M NaOH medium, 93.750% for copper in 0.5?M HCl medium, and 90.000% for copper in 0.5?M NaOH medium). Protection efficiency values are inverse relationship with the temperature, which indicates the physical nature of protective film on the metal surface. Adsorption characteristics of the MAH extract on the electrode surface in a hostile fluid environment are consistent with the Langmuir isotherm model under study conditions, which indicates the monolayer formation of inhibitor on electrode surfaces. Results of Tafel study confirm that MAH extract acts as an effective anodic type of inhibitor for the system copper in 0.5?M NaOH system, in the rest of the cases, it acts as a mixed type of inhibitor. From the Nyquist plot, it is clear that increased depressed semicircle area with an increase in MAH extract concentration is an evidence of the inhibitory role of plant extracts on the metal surface. Further, Fourier transform infrared spectroscopy and scanning electron microscopy techniques clearly indicated the protective film-forming ability of the MAH extract on the metal surface.     

Cationic gemini surfactant as corrosion inhibitor for mild steel in 1 M HCl and synergistic effect of organic salt (sodium tosylate)

Synergistic result of cationic gemini surfactant (GS) 1,2-bis(N-hexadecyl-N,N-dimethylammonium) ethane dibromide (16-2-16) and organic salt (Sodium tosylate; NaTos) on mild steel corrosion in 1?M HCl solution at various temperatures (30, 40, 50 and 60?°C) has been examined using gravimetric, electrochemical and surface morphology measurement. Investigational result shows that the inhibition efficiency (η) of 16-2-16 GS enhanced in the existence of a set quantity of NaTos. The synergism parameter (S_θ) values are larger than unity, representing large inhibition efficiency, generated via the accumulation of NaTos to 16-2-16 GS is owing to adsorption supportive. The electrochemical results revealed that the 16-2-16 GS in the absence and presence of NaTos act as mixed-type inhibitors. The inhibitor adsorption on the mild steel surface in 1?M HCl solution obeys Langmuir adsorption isotherm. Surface morphology was studied using scanning electron microscopy (SEM).     

Electrochemical preparation and characterization of nickel and zinc-modified poly-2-aminothiazole films on mild steel surface and their corrosion inhibition performance

Poly-2-aminothiazole (pAT) was electrochemically synthesized on a mild steel (MS) specimen from 0.3 M aqueous ammonium oxalate solution containing 0.01 M 2-aminothiazole (2-AT) using cyclic voltammetry technique. The synthesized polymer film was then modified by electrodeposition of 100 μg cm⁻² Ni (MS/pAT–Ni) and Zn (MS/pAT–Zn) on top of the polymer surface. The surface morphologies of the polymer films were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The elemental analysis of the surface films was performed by energy dispersive X-ray spectroscopy (EDX). The effectiveness of the coatings in preventing corrosion of MS in 3.5% NaCl solution was assessed using electrochemical techniques. It was found that the obtained coatings were adherent to the steel surface. The pAT film provided a good corrosion protection against the attack of corrosive environment. Moreover, the modification of pAT film by deposition of Ni and Zn on top of the polymer surface significantly enhances the corrosion protection performance of the polymer film by exhibiting an improved barrier effect against the attack of corrosive environment. The surface morphologies and protection ability of the layers were found to be dependent on the type of deposited metal.     

Performance evaluation of poly (methacrylic acid) as corrosion inhibitor in the presence of iodide ions for mild steel in H2SO4 solution

The inhibition performance of poly (methacrylic acid) (PMAA) and the effect of addition of iodide ions on the inhibition efficiency for mild steel corrosion in 0.5 M H₂SO₄ solution were investigated in the temperature range of 303–333 K using electrochemical, weight loss, scanning electron microscopy (SEM), and water contact angles measurements. The results show that PMAA is a moderate inhibitor for mild steel in 0.5 M H₂SO₄ solution. Addition of small amount of KI to PMAA significantly upgraded the inhibition efficiency up to 96.7%. The adsorption properties of PMAA and PMAA + KI are estimated by considering thermodynamic and kinetic parameters. The results reveal that PMAA alone was physically adsorbed onto the mild steel surface, while comprehensive adsorption mode characterized the adsorption of PMAA + KI. Adsorption of PMAA and PMAA + KI followed Temkin adsorption isotherm. The SEM and water contact angle images confirmed the enhanced PMAA film formation on mild steel surface by iodide ions.     

Effect of some substituted anilines‐formaldehyde polymers on mild steel corrosion in hydrochloric acid medium

The influence of linear copolymer of amines and formaldehyde namely poly(aniline‐formaldehyde) (Inh1), poly(o‐toluidene‐formaldehyde) (Inh2), and poly(p‐chloroaniline‐formaldehyde) (Inh3) on corrosion of mild steel in hydrochloric acid was evaluated by weight loss measurements, linear polarization, Tafel polarization, and electrochemical impedance spectroscopy. These polymers showed very high inhibition efficiency at very low concentrations. Results obtained showed that all inhibitors are mixed inhibitors and participate in reaction probably in the form of metal inhibitor complex on metal surface. Atomic force microscopic studies reveal that the surface of metal is quite unaffected after use of inhibitor in hydrochloric acid solution. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Investigation of adsorption and inhibitive effect of 2-mercaptothiazoline on corrosion of mild steel in hydrochloric acid media

The inhibition effect of 2-mercaptothiazoline (2MT) on the corrosion behavior of mild steel (MS) in 0.5 M HCl solution was studied in both short and long immersion times (120 h) using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) techniques. For long-term tests, hydrogen gas evolution (VH₂−t) and the change of the open circuit potential with immersion time (E_ocp − t) were also measured in addition to the former three techniques. The surface morphology of the MS after its exposure to 0.5 M HCl solution with and without 1.0 × 10⁻² M 2MT with the different immersion times was examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The thermal stability of the inhibitor film was investigated by thermogravimetric analysis (TGA). The value of activation energy (E_a) for the MS corrosion and the thermodynamic parameters such as adsorption equilibrium constant (K_ads), free energy of adsorption (ΔG_ads), adsorption heat (ΔH_ads) and adsorption entropy (ΔS_ads) values were calculated and discussed. The potential of zero charge (PZC) of the MS in inhibited solution was studied by the EIS method, and a mechanism for the adsorption process was proposed. The results showed that 2MT performed excellent inhibiting effect for the corrosion of the MS. Finally, the high inhibition efficiency was discussed in terms of adsorption of inhibitor molecules and protective film formation on the metal surface. TGA results also indicated that the inhibitor film on the surface had a relatively good thermal stability.