Anodic Inhibitor Research Articles

Corrosion inhibition of mild steel by the hydrolysate of an imidazoline-based inhibitor in CO2-saturated solution.

The synthesized imidazoline phosphate quaternary ammonium salt has low stability, which is spontaneously and rapidly hydrolyzed to the long-chain fatty acid amide (LFA). The hydrolysate (LFA) has been found to be an efficient inhibitor for Q235 steel against CO2 corrosion, which yields a maximum value above 90% at a concentration of 1000 mg L−1. The LFA inhibitor acts as an anodic type inhibitor and its inhibition mechanism is a “negative catalysis effect”. The heteroatoms in the acyl, amine and phosphate groups in the LFA molecule are the active centers to bond with Fe atoms to form a chemisorbed film on the steel surface.

Corrosion Inhibition Behavior of Dual Phase Steel in 3.5 wt % NaCl Solution by Carica Papaya Peel Extracts

Abstract Corrosion behavior of dual phase steel was studied in 3.5 wt % NaCl solution and carica papaya peel extracts. Different concentrations of carica papaya peel extract were added to the salt solution to perceive the inhibition effect on corrosion of dual phase steel. Concentration of peel extract was varied from 50 -100 %. It is observed that with the increase in concentration of peel extract, the corrosion rate is decreasing. The rate of corrosion in salt solution is found to be more as compared to the corrosion rate obtained from 100 % peel extract solution. Therefore, carica papaya peel extract is a good corrosion inhibitor for dual phase steel. The inhibition efficiency increases from 66.31 to 98.67 %. Shift of Ecorr value in positive direction indicates that peel extract is an anodic type inhibitor. Impendence study was carried out to acquire knowledge about the solution resistance and charge transfer resistance offered by the film.

Investigation of corrosion inhibition of C38 steel in 5.5 M H3PO4 solution using Ziziphus lotus oil extract: an application model

PurposeThis study aims to investigate the corrosion inhibition effect of extracted oil from Ziziphus lotus fruit on corrosion of C38 carbon steel in 5.5 M H3PO4 solution using potentiodynamic polarization and impedance techniques.Design/methodology/approachOil composition was determined using gas chromatography, and the results showed that oleic and palmitic acids present approximately 84.0 per cent of its total chemical content. Electrochemical impedance spectroscopy (EIS) data were analyzed by adapting it to a well-developed electric circuit model. The inhibition efficiency of Z. lotus oil was calculated and compared using Tafel polarization and EIS.FindingsAccordingly, the oil extract was found to act as an anodic type inhibitor. Furthermore, inhibition efficiency of Z. lotus oil extract increase with oil concentrations and achieve approximately 70.5 per cent at 3 g/L solution of Z. lotus oil.Originality/valueThe results obtained from different tested methods were in line, and the oil was able to reduce significantly the kinetics of the corrosion process of C38 carbon steel.

Application of green products for industrially important materials protection: An amusing anticorrosive behavior of tender arecanut husk (green color) extract at metal-test solution interface

The sustainable corrosion impediment of tactic central materials such as mild steel and copper is the subject of utmost importance in contemporary civilization due to their wide spread utility in industrial sectors. This part reports the outcome of chemical (weight loss) and electrochemical measurements on the inhibition of corrosion of mild steel and copper metals in both 0.5 M HCl and 0.5 M NaOH media. Weight loss measurements divulged that, corrosion protection efficiencies were enhanced with increment in the concentration of plant extracts which indicates that dissolution process was stifled; whilst a decrease was noticed with the rise of solution temperature at habitual acid and base concentration is plausible due to thermal agitation of plant extract constituents from the metal surfaces. The maximum protection efficiency observed with immersion period of one hour at 303 K. (93.750% for copper in acid medium, 90% for copper in alkali medium, 93.478% for MS in acid medium and 91.66% for MS in alkali medium). The probable inhibitive modality mechanism of most potent green inhibitor was further corroborated by kinetic and thermodynamic models. Electrochemical studies like, Tafel plot and AC impedance studies were used for appraisingthe green inhibitor behavior. The Tafel plot studies shows that, AH extract act as mixed type corrosion inhibitor for copper in acid media, mild steel in acid and alkali media, whereas AH extract act as anodic type corrosion inhibitor for copper in alkali media. The results of chemical and electrochemical techniques proved that, tender arecanut husk (AH) extract was the most efficacious eco-friendly corrosion inhibitor for mild steel and copper metals in both HCl and NaOH media with a concentration-dependent mode. Surface depiction via scanning electron microscopy (SEM) technique surmised the dearth of corrosion products and topographic amendment of the studied metals. Therefore, technological and economic profit is envisaged from an affirmative result in this study.

Control the corrosion of mild steel using synthesized polymers based on polyacrylamide

In this work polyacrylamide (PACM) was prepared by radical polymerization technique using ammonium persulfate (APS) as initiator under nitrogen atmosphere. The viscosity average molecular weight of the prepared PACM was found to be 177858. The free amino groups of PACM, poly(2-methoxyaniline) was grafted by the oxidation of 2-methoxyaniline using APS in acidic medium under nitrogen atmosphere. The grafting percent is found to be 96%. The morphology of the obtained PACM and PACM-g-P2-MeOANI was studied by X-ray diffraction and scanning electron microscope. The grafting process enhances the morphology of both PACM and poly(2-methoxyaniline). The inhibiting effect of the three polymers on the mild steel corrosion in the 1.0 M HCl as aggressive environments have been measured gravimetrically at three different temperatures 25, 40 and 55 °C and electrically at 25 °C. The inhibition efficiencies of the three tested polymers were found to increase with temperature. The poly(2-methoxyaniline) is the most effective one as a corrosion inhibitor at all tested temperatures. The adsorption behavior of the polymers was found to follow Villamil isotherm and the values of the change in free energy refer to a mixed chemical and physical adsorption on the steel surface. Tafel curves indicate that the tested polymers act as mixed anodic and cathodic inhibitor. The double layer capacitance was found to decrease with increasing the inhibitor concentration.

Water-soluble carboxymethylchitosan used as corrosion inhibitor for carbon steel in saline medium

Biodegradability and ecotoxicity of products used in oil industry are of great relevance and corrosion inhibitor could not be an exception. In earlier reports, chitosan and some derivatives were evaluated as corrosion inhibitors at acid pH, mainly due to polymer solubility. An eco-friendly corrosion inhibitor with water solubility in all pH range should be ideal, as well as that could act under the high salinity of oil field environment. Thus, herein is presented the performance of a water-soluble carboxymethylchitosan (CMC) as corrosion inhibitor in presence of chlorides (3.5% NaCl) in 1020 carbon steel, without any addition of acid or base. CMC showed good properties as corrosion inhibitor in media containing Cl−, and behaved as an anodic inhibitor. CMC exhibited inhibitory efficiency of about 80% and 67%, according to Tafel curve and electrochemical impedance, respectively, which was attributed to chemisorption mechanism (ΔGads ≈ −45 kJ/mol).

Corrosion protection of carbon steel using hydrotalcite/graphene oxide nanohybrid

Zinc aluminum hydrotalcite/graphene oxide (HTC-GO) nanohybrid as inhibition additive for organic coatings was prepared using the co-precipitation method. The synthesized HTC-GO was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy, and thermogravimetric analysis. Surface charge properties of HTC-GO were evaluated with zeta potential measurement. The corrosion inhibition effect of HTC-GO on carbon steel in NaCl solution was investigated using electrochemical methods, energy-dispersive X-ray, and SEM. The effect of HTC-GO on corrosion resistance of epoxy coating applied on carbon steel was evaluated by salt spray test. It was shown that hydrotalcite structures were formed on GO surface, subsequently becoming hydrotalcite/graphene oxide nanohybrid. The results obtained by electrochemical measurements indicate that HTC-GO is an anodic corrosion inhibitor with an inhibition efficiency of about 92% at 1 g/L concentration. The presence of intercalated GO improved the barrier properties and adsorption of HTC-GO on steel surface. The corrosion resistance of epoxy coatings was improved with 1 wt% HTC-GO.

Nitrite producing bacteria inhibit reinforcement bar corrosion in cementitious materials

Chemicals and synthetic coatings are widely used to protect steel against corrosion. Bio-based corrosion inhibition strategies can be an alternative in the arising bioeconomy era. To maintain the good state of steel reinforcement in cracked concrete, microbe-based self-healing cementitious composites (MSCC) have been developed. Yet, proposed strategies involve reasonably slow crack filling by biomineralization and thus risk the possible rebar corrosion during crack healing. Here we upgrade the rebar protection to a higher level by combining MSCC with microbial induced corrosion inhibition. Presented NO3− reducing bacterial granules inhibit rebar corrosion by producing the anodic corrosion inhibitor NO2− and meanwhile heal a 300-µm-wide crack in 28 days. During 120 days exposure to 0.5 M Cl− solution, the rebars in cracked MSCC keep showing open circuit potentials above the critical value of −250 mV and they lose less than 2% of the total rebar material which corresponds to half the material loss in cracked plain mortar. Overall, the obtained rebar protection performance is comparable with that of uncracked mortar and mortar containing chemical inhibitor, hence the microbe-based system becomes an alternative to the traditional methods.

AN INVESTIGATION ON CORROSION INHIBITORS FOR STEEL IN ETHANOL FUEL BLEND

Cerium (III) chloride, sodium 4-hydroxycinnamate, and cerium 4-hydroxycinnamate have been successfully characterized as effective anodic, cathodic, and mixed inhibitors for steel in ethanol fuel blend by electrochemical and surface analyses. Electrochemical and surface analyses indicate that good inhibition performances are due to the formation of protective layer as a result of adsorption between the metal and inhibitor components. In addition, the inhibition mechanism of each inhibitor is also suggested and discussed in detail.

Continuous Studies on Using Camel’s Urine as Nontoxic Corrosion Inhibitor–Corrosion Inhibition of Al–Cu Alloy in Alkaline Solutions

The corrosion inhibition of Al–Cu alloy in 0.5 M NaOH using various concentrations of camel urine (CU) was investigated using hydrogen evolution, weight loss, electrochemical impedance spectroscopy and potentiodynamic polarization measurements. Analysis of impedance spectra revealed that CU inhibits the corrosion of the studied alloy effectively through the formation of a protective film on its surface with a resistance increasing with increasing CU concentration. Polarization studies indicated that CU was a mixed-type inhibitor except for CU concentrations > 3 mL% where it behaves predominantly as an anodic inhibitor. Hydrogen evolution plots were analyzed using shrinking core models for solid–liquid heterogeneous systems. The resultant data revealed that after certain induction period, hydrogen evolution occurs by fast reaction followed by slow reaction and the latter is controlled by diffusion. The values of IE% obtained from hydrogen evolution and weight loss measurements were temperature dependent. Generally, the inhibitor performance decreased at relatively high temperature (60 $$^{\circ }$$ C) except for low CU concentrations (< 3 mL%) the inhibition efficiency improved with temperature increase. The apparent activation energy for Al–Cu alloy corrosion in the inhibited solutions was calculated and compared with that in the uninhibited solution. El-Awady and Temkin adsorption isotherms fit well the adsorption data obtained from weight loss at 30 $$^{\circ }$$ C and 60 $$^{\circ }$$ C. Based on El-Awady and Temkin isotherms, multilayer film formation with repulsive forces between the adsorbed molecules was suggested. Various thermodynamic parameters for the adsorption process were calculated and discussed. Thermodynamic data indicated comprehensive adsorption (chemisorptions and physical adsorption). Good assessment to correlate the inhibition mechanism with the CU composition was obtained.

Corrosion Inhibition of Mild Steel in 1.0 M HCl Solution by Anhydrous Tricalcium Phosphate

Objective:In this study, electrochemical measurements were used to characterize Anhydrous Tricalcium Phosphate (ATP) as a corrosion inhibitor for mild steel in 1.0 M HCl.Method:The potentiodynamic polarization curves indicated that the ATP reacts as an anodic type inhibitor. In addition, it has been found that the electrochemical impedance confirms the inhibitor character of ATP obtained by the potentiodynamic polarization curves where the inhibition efficiency increases by its concentration to reach a maximum of 93.79 % at 10-4M. The temperature solution influence indicated that the corrosion rate increases with temperature while the inhibitor acts actively. Thermodynamic adsorption and activation parameters indicated that the ATP acts by physical adsorption on the metallic surface with an endothermic process of metal dissolution.Result:Additionally, it was found that the adsorption of ATP molecules obeyed to the Langmuir isotherm. Surface analyses via scanning electron microscopy (SEM) was used to investigate the morphology of mild steel before and after immersion in 1.0 M HCl solution without and with 10-4M of ATP. It is revealed that the ATP acted by the formation of a protective layer on the mild steel.

New, environmentally friendly, rare earth carboxylate corrosion inhibitors for mild steel

Four recently synthesized rare earth 3-(4-methylbenzoyl)propanoate (mbp) compounds (RE = La, Ce, Nd and Y) were evaluated as corrosion inhibitors for mild steel in 0.01 M NaCl. At a concentration of 0.25 mM all the compounds showed some level of inhibition after 30 min immersion, with the Y(mbp)3 complex giving the largest reduction in corrosion current density, from 1.92 μA/cm2 for the control sample to 0.25 μA/cm2 for the Y based inhibitor. All the RE(mbp)3 inhibitors acted predominantly as anodic inhibitors, showing little effect on the cathodic reaction after 30 min. Surface analysis after 6 h immersion using FTIR and EDS detected the presence of a thin film containing inhibitor components on all surfaces, thus accounting for the reduced corrosion rate, with the Y(mbp)3 compound having the most significant effect on corrosion and showing the most uniform surface coverage.

The interface electrochemical and chemical mechanism of a low alloy steel in a 3.5% NaCl solution containing Ce3+‐based inhibitor

The interface electrochemical and chemical mechanism of the low alloy steel in a 3.5% NaCl solution containing the Ce3+‐based inhibitor was investigated by the electrochemical techniques in conjunction with the surface analysis technologies. It was shown that the Ce3+‐based inhibitor was an anodic inhibitor with more than 90.0% inhibitory efficiency. The net‐shaped inhibiting film with 200 to 500‐nm greyish balls was observed on the specimen surface. During the corrosion reaction occurred on the surface of the low alloy steel, the hydrolysis reaction of P3O105− and the disproportionation reaction of Ce3+ ions simultaneously occurred, too, resulting in the formation of the net‐shaped inhibiting film with nano‐scale greyish ball‐type products, which contained Ce element and had an obvious effect on the electrochemical process of the low alloy steel in a 3.5% NaCl solution containing the Ce3+‐based inhibitor. Therefore, the EIS spectra of the low alloy steel in a 3.5% NaCl solution containing the Ce3+‐based inhibitor were composed of a capacitive loop at a high‐frequency region and an inductive impedance loop at a low‐frequency region. The charge‐transfer resistance (Rt) increased with the immersion elapsed time, indicating that the inhibition efficiency of the Ce3+‐based inhibitor increased with immersion elapsed time. The calculated data based on the fitted electrochemical parameters showed the partial coverage of the inhibitor. This was further revealed by the analysis of electrochemical kinetics that the inductive impedance (L) loop at a low frequency region resulted from the localized absorption of the Ce3+‐based inhibitor on the surface of the low alloy steel in a 3.5% NaCl solution. It was also verified by micro‐morphologies.

Experimental and Quantum Chemical Investigation of Imidazole Derivatives as Corrosion Inhibitors on Mild Steel in 1.0 M Hydrochloric Acid

The inhibitive performance of two imidazole derivatives, namely, 1,4,5-triphenyl-2-(4-metyoxyphenyl)-1H-imidazole (P1) and 1,4,5-triphenyl-2-(3,4,5-trimetyoxyphenyl)-1H-imidazole (P2) on the corrosion of steel in hydrochloric acid 1.0 M, has been studied by weight-loss measurement, polarization method, and electrochemical impedance spectroscopy (EIS) and theoretical computational chemistry techniques. The value of inhibition efficiency increases as inhibitor concentration becomes high. The Polarization results indicated that these compounds act as anodic inhibitors in HCl solution. P1 and P2 showed the best protection performances for mild steel in the studied medium. Quantum chemical calculations also showed that imidazole ring has the tendency of interacting with metallic atoms via both forward and backward donations.

Corrosion Monitoring and Inhibition of Buried Pipes in a Nuclear Power Plant Using a FEM Method or Mixed Inhibitors

Several kinds of pipes in a nuclear power plant were buried in the soil. In order to control the corrosion problems, cathodic protection has been applied to protect the corrosion process in the outer surface of pipes and several corrosion inhibitors have been used to minimize the corrosion in the inner surface of the pipes. This work focused on the corrosion monitoring of the outside of coal tar-coated pipes buried in a nuclear power plant using a FEM method and the corrosion inhibition of the inside of the pipes using mixed inhibitors. The pipes buried in a nuclear power plant were ductile cast iron and these have been suffered under very high cathodic protection condition beyond the appropriate condition. However, cathodic potential measured in the site reveals the non-protected status. Converting from 3D CAD data of the power plant to appropriate type for a FEM simulation was performed and cathodic potential under the applied voltage and current was calculated using the primary and secondary current distribution physics conditions. FEM simulation for coal tar-coated pipe without defects showed the over-protection condition if the pipes are well-coated. On the other hand, we compared the different inhibition mechanisms of organic inhibitor with that of anodic inhibitor. When ethanolamines or nitrite or molybdate were added separately to tap water for inhibiting the corrosion of ductile cast iron, large amounts of inhibitor were needed. However, when mixed inhibitors were added, their amounts were greatly reduced and we found the synergistic effect and also proposed the new mechanism.

INVESTIGATION OF CERIUM (III) ACTIVATED-CERIA NANOPARTICLES AS CORROSION INHIBITORS FOR CARBON STEEL

The present work investigated the corrosion protection performance of ions Ce3+ activated-cerium(IV) oxides nanoparticles for carbon steel in a NaCl solution. Ceria nanoparticles were synthesized by homogeneous precipitation in ethanol/water mixed solvent. The obtained CeO2 nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). The corrosion inhibition action of the activated nanoparticles by cerium(III) ions on carbon steel in NaCl solution was evaluated by electrochemical measurements (electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization). Then, the effect of cerium salt activated-CeO2 on the protection properties of poly-vinyl-butyral (PVB) coating deposited onto carbon steel plate was studied by salt spray test. The obtained results showed that the salt activated-nanoparticles are anodic corrosion inhibitors. The presence of Ce3+ activated CeO2 in the coating improved the barrier properties and corrosion protection performance of the PVB coating. No swellings of coating were observed after 48 hours of exposure in salt spray chamber.

CORROSION INHIBITION OF CARBON STEEL BY LDH/GO HYBRID INTERCALATED WITH 2-BENZOTHIAZOLYTHIO-SUCCINIC ACID

Layered double hydroxide/graphene oxide hybrid (LDH/GO) intercalated with corrosion inhibitor 2-benzothiazolylthio-succinic acid (BTSA) was prepared using co-precipitation method. The synthesized LDH/GO-BTSA was characterized by FTIR, XRD and SEM. The inhibitive action of LDH/GO-BTSA on carbon steel was evaluated and compared with LDH-BTSA by electrochemical measurement. It was shown that the GO and BTSA were intercalated in LDH structure. The obtained results showed that LDH/GO-BTSA is anodic corrosion inhibitors, and the inhibition efficiency was 94 % at concentration of 1 g/l.

Optimization of an efficient, economic and eco-friendly inhibitor based on Sesbania grandiflora leaf extract for the mild steel corrosion in aggressive HCl environment

PurposeThis paper aims to evaluate the inhibitive action of different concentrations of Sesbania grandiflora leaf extract on the mild steel corrosion in an aggressive HCl medium under different experimental conditions.Design/methodology/approachWeight loss investigation, open-circuit voltage analysis, Tafel polarisation, AC impedance analysis, etc. were used for the evaluation of inhibition efficiency. The influence of immersion period on inhibition efficiency was evaluated. The mechanism of action of the inhibitor is also discussed. Infrared (IR) spectroscopy and energy-dispersive X-ray spectroscopy analysis were used to characterise the passive film.FindingsThe results suggested that 10,000 ppm solution has maximum inhibition efficiency of 98.01 per cent at room temperature, while 1,000 ppm solution also exhibited a better efficiency of about 96.16 per cent. Efficiency of inhibitor solution was found to increase with an increase in its concentration. Polarisation study proposed the solution as an anodic inhibitor. Impedance study confirmed the formation of a protective layer over the surface of the specimen, and the constituents of the film were identified using IR spectroscopy. Stability of the film adsorbed on the steel was cleared from the steady open-circuit potential value. Study on action of the inhibitor under accelerated conditions revealed the fact that the efficiency of extract in preventing corrosion is good under stimulated conditions also.Practical implicationsThe action of inhibitor sustains for a sufficient time period and could sustain under stimulated conditions. Hence, its application is practically possible in industries. The proposed inhibitor is widely available and is environmentally safe.Originality/valueHCl is an industrially important chemical used for acid cleaning, acid pickling, etc. HCl was used as an aggressive corrosion environment. As the chances for mild steel to be in contact with HCl were very high, it was important to develop an efficient, economical and eco-friendly inhibitor for corrosion.

Experimental and theoretical study on corrosion inhibition performance of environmentally benign non-ionic surfactants for mild steel in 3.5% NaCl solution

Abstract Two ‘natural’ non-ionic surfactants namely, N-alkyl-N′-glucosylethylenediamine with formula CnH2n+1NH(CH2)2NHCO(CHOH)4CH2OH (n = 10, 12), designated as Glu (n) were prepared and identified by FT-IR and 1H NMR. Synthesized compounds were investigated for mild steel corrosion in 3.5% NaCl medium using electrochemical measurement, gravimetric measurement and surface characterization techniques like Fourier transform infra-red spectroscopy (FT-IR), atomic force microscopy (AFM) and scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDAX). The compounds act as predominantly anodic corrosion inhibitors and their inhibition efficiencies are observed to increase with increasing inhibitors’ concentrations, chain length and temperature. The adsorption of Glu (n) inhibitor on the mild steel surface in 3.5% NaCl solution followed the Langmuir adsorption isotherm. The AFM micrographs showed a reduction of surface roughness in the presence of the investigated inhibitor. SEM micrographs confirmed the existence of an adsorbed protective film on the mild steel surface. EDAX was carried out to characterize the chemical composition of the inhibitive film formed on the steel surface. Density functional theory (DFT) calculations are made to correlate the efficiencies of Glu (n) with their intrinsic molecular parameters.

Corrosion inhibition of carbon steel by hydrotalcites modified with different organic carboxylic acids for organic coatings

Hydrotalcites intercalated with sebacate (HT-SB) were prepared by a coprecipitation method. The synthesized powder was characterized using infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and zeta potential measurements. The inhibitor release from HT-SB in a chloride solution has been determined by total organic content (TOC) analysis. The inhibitive action of HT-SB on carbon steel was investigated and compared with hydrotalcites intercalated by benzoate (HT-BZ) and 2-benzothiazolythio-succinic acid (HT-BTSA) using electrochemical measurements and SEM/EDX analysis. The results showed that the zeta potential of modified hydrotalcites and the release of corrosion inhibitors from modified hydrotalcites depend on the chemical structure of inhibitors. The anodic polarization curves showed that the three modified hydrotalcites behave as anodic corrosion inhibitors with an efficiency, at a concentration of 3 g/L, of 94% for HT-SB, 81% for HT-BZ and 92% for HT-BTSA. These efficiencies are higher than those measured for the organic inhibitors in chloride solutions highlighting a synergistic effect due to the combination of the hydrotalcite structure and carboxylate inhibitors. The inhibition effect of modified hydrotalcite depends not only on the intercalated organic inhibitors but also on the capability of adsorption of the hydrotalcite structure on a steel surface. HT-SB was easily dispersed in an epoxy coating improving the barrier properties at concentrations lower than 5 wt.%. The best protection was obtained with 1.5 wt.% HT-SB.