Steel In Sulfuric Acid Medium Research Articles

Optimisation of the corrosion inhibition performance of isatin 4-ethyl-3-thiosemicarbazone for mild steel in sulfuric acid medium using response surface methodology

Optimisation of the corrosion inhibition performance of isatin 4-ethyl-3-thiosemicarbazone for mild steel in sulfuric acid medium using response surface methodology

Encapsulation of Acacia bark extract (Acacia mangium) by maltodextrin-carrageenan for corrosion inhibition steel in sulfuric acid medium

Encapsulation of Acacia bark extract (Acacia mangium) by maltodextrin-carrageenan for corrosion inhibition steel in sulfuric acid medium

A MIXTURE OF ACACIA BARK EXTRACT (Acacia mangium Willd) AND POTASSIUM IODIDE AS A CORROSION INHIBITOR IN SULFURIC ACID SOLUTION

Corrosion is a decrease in the quality of a metal material caused by a reaction with the environment. Corrosion cannot be eliminated, but corrosion can be slowed down in several ways by adding corrosion inhibitors and synergistic effects. Acacia bark extract (Acacia mangium Willd) with the addition of 0.02 M KI has the potential as a corrosion inhibitor for steel because it contains secondary metabolites, so it can provide a synergistic effect and increase the value of inhibition efficiency on steel. This research aimed to analyze the effect of a mixture of acacia bark extracts (Acacia mangium Willd) with the addition of KI on inhibition efficiency corrosion of mild steel in sulfuric acid media. The method used in this study is the method of weight loss, adsorption isotherms, and thermodynamic parameters, which were carried out by varying the concentration of acacia bark extract and the immersion temperature of the steel. To strengthen the research results, characterization was carried out using FTIR and SEM. The results showed that the corrosion rate of mild steel immersed in 0.75 M H2SO4 corrosive medium with the addition of 0.02 M KI increased with increasing immersion temperature. These results are reinforced by the results of FTIR and SEM analysis which show that there is an interaction between mild steel and acacia bark extract (Acacia mangium Willd) and KI 0.02 M. Based on the thermodynamic parameters, the resulting values of ∆Hads, ∆Gads, and ∆Sads show that the adsorption process of acacia bark extract (Acacia mangium Willd) in corrosive medium H2SO4 0.75 M with the addition of 0.02 M KI took place spontaneously, showing the type of physical adsorption, adsorbed stable, the adsorption process was exothermic and the degree of irregularity in the adsorption process. The inhibition efficiency of acacia bark extract (Acacia mangium Willd) with the addition of 0.02 M KI was highest at 60 °C with an extract concentration of 2.5 g/L of 81%. The higher the immersion temperature, the greater the resulting synergistic effect

Novel N-heterocyclic Schiff base based on Isatin derivative as a sustainable, eco-friendly, and highly efficiency corrosion inhibitor for carbon steel in sulfuric acid medium: Electrochemical and Computational investigation

The present study aimed to synthesize and investigate the inhibitory effects of two novel Schiff bases namely: (Z)− 1-(5-nitro-2-oxoindolin-3-ylidene) semicarbazide (NOSC) and Z)− 1-(5-nitro-2-oxoindolin-3-ylidene) thiosemicarbazide (NOTSC) for carbon steel (CS) corrosion in 0.5 M H2SO4 medium. Through chemical and electrochemical investigations, the efficiency of NOSC and NOTSC's corrosion inhibition was ascertained experimentally at 298 K. It is noteworthy that the inhibitory efficacy of NOTSC and NOSC reached 93.4% and 91.6%, respectively, at a concentration of 10−3 M. Studies using potentiodynamic polarization revealed that NOTSC and NOSC functioned as mixed-type inhibitors. A depressed capacitive loop with varying concentrations is the primary way that the Nyquist plot of impedance is represented. The transportation of corrosive ions to the metal substrate is impeded by the adsorption of both NOSC and NOTSC, as determined by the Langmuir isotherm. Apart from the chemical and electrochemical investigations, additional insights were gained into the inhibitory mechanism by the application of density functional theory (DFT), molecular dynamics simulation (MDS), and an understanding of the molecular structure of NOTSC and NOSC. A robust correlation was discovered between the theoretical and experimental results through the application of DFT/MDS computational study.

Corrosion mitigation of peanut shell extract as a novel effective corrosion inhibitor for carbon steel in sulfuric acid medium

The extract of peanut shell extract (PSE) is firstly utilized as a novel eco-friendly corrosion inhibitor for the mitigation of corrosion on carbon steel in 0.5 M sulfuric acid medium. The corrosion inhibition performance and adsorption properties of PSE were researched via weight loss, electrochemical measurements and surface characterization analysis. It is demonstrated that the PSE acts as a mixed type inhibitor with a superb inhibition ability of 95 % with the addition of 300 mg/L PSE. The adsorption of the active ingredients in PSE on steel surface contributes to effective corrosion inhibition. The outstanding inhibition efficiency and straightforward extraction method with environment-friendly solvent convincingly demonstrate that the PSE possesses promising application prospects to be a novel eco-friendly corrosion inhibitor in industrial corrosion mitigation.

Investigation Effect of 4-Aminophenol as a Corrosion Inhibitor for Mild Steel in Sulfuric Acid Medium

A high number of organic materials have been studied as inhibitors for corrosion in different conditions. In this paper, the effect of organic chemical (4-Aminophenol) as an inhibitor for mild steel metal corrosion was investigated in presence of sulfuric acid at different temperatures. The study was carried out using three known methods in testing corrosion process, methods of weight loss, thermometric, and polarization. The obtained results showed that when the inhibitor concentration increases, the corrosion rate decreases, and hence, the inhibition efficiency increases. Moreover, when the surface coverage at a temperature of 313 °C with organic inhibitor increases, the corrosion rate decreases as noticed in the weight loss method. For the thermometer method, the inhibitor was examined by temperature. The inhibition efficiency increases, as well as in the anodic and cathodic polarization method, where it is observed that the anodic and cathodic curves are present to measure the corrosion current and corrosion potential. As the higher the concentration of the inhibitor, the lower the current and the corrosion voltage. The reason for the effectiveness of this inhibitor is the presence of amine and phenol organic molecules in its composition, which can form a film on the metal surface and prevent corrosion from taking place.

Insight into anti-corrosion mechanism of Dalbergia odorifera leaves extract as a biodegradable inhibitor for X70 steel in sulfuric acid medium

Dalbergia odorifera leaves extract (DOLE) was obtained by soaking, filtering, and freeze-drying with 0.5 M H2SO4 solution as solvent. The corrosion inhibition performance of X70 steel by DOLE was systematically studied by electrochemical research methods, surface morphology test, infrared spectrum test and theoretical calculation. The electrochemical test data show that the addition of DOLE in sulfuric acid medium can vastly reduce the electric double layer capacitance (Cdl) value of the steel/acid interface, improve the charge transfer resistance, and simultaneously retard the cathodic and anodic reactions of X70 steel. The DOLE reaches 400 mg/L, the anti-corrosion efficiency (η) is 96 %. Fourier transform infrared spectroscopy (FTIR) test data show that DOLE contains a large number of hydroxyl groups, carbonyl groups and unsaturated functional groups, and a large number of lone electron pairs can coordinate with the empty d orbital of Fe, which leads to the formation of chemical adsorption of DOLE at X70 steel. The morphology test showed that the corrosion level of X70 steel decreased memorably after adding DOLE. The adsorption model study manifests that the adhere of DOLE at the interface of X70 steel comply with the Langmuir adsorption isotherm. Theoretical calculation demonstrate that DOLE can exhibit high-level inhibition property.

Insight into the anti-corrosion mechanism of Pisum sativum L leaves extract as the degradable inhibitor for Q235 steel in sulfuric acid medium

BackgroundIn this work, we obtained Pisum sativum L leaf extract by soaking in sulfuric acid solution. Using sulfuric acid solution as solvent, the prepared Pisum sativum L leaf extract (PSLLE) has good solvent property and can be effectively dissolved in H2SO4 solution. Pisum sativum L leaf was selected as the research object, which is attributed to the large amount of Pisum sativum L cultivated in many countries and regions on the earth. Pisum sativum L leaf as a corrosion inhibitor, it can greatly realize the transformation of waste into treasure. MethodsThe Tafel curve data manifest that PSLLE is mixed-type inhibitor, which concurrently delaying the anodic and cathodic reactions of working electrode in sulfuric acid environment. Surface topography test results prove that PSLLE can form the stabilized isolation film after adsorption of Q235 steel, and the corrosion of Q235 steel is significantly descend. Theoretical results indicate that the active ingredient in PSLLE can emerge high standard anti-corrosion nature. Significant findingsWhen the concentration of PSLLE is 600 mg/L, its corrosion inhibition efficiency can reach 95.9% at 298 K. With the increase of temperature, PSLLE can still show high anti-corrosion performance. The adsorption isotherm model data showed that there was chemical and physical co-adhesion of PSLLE onto the Q235 steel surface. The PSLLE adhesion at Q235 steel surface is consistent with Langmuir monolayer model.

The New Organic Molecule-Based Epoxy Resin as an Effective Corrosion Inhibitor for Mild Steel in Sulfuric Acid Medium

The influence of organic molecule based from Epoxy Resin Octa-functional (REO) on the corrosion inhibition of mild steel in the presence of 0.5 M H2SO4 at different temperatures have been studied using polarization, EIS and computational methods. Polarization curves indicate that REO is a mixed inhibitor. EIS measurements show an increase of the transfer resistance with increasing inhibitor concentration. The inhibition efficiency of REO reaching 98% was observed at 10–3 M concentration. The inhibitor adsorption is chemical adsorption compound using the Langmuir adsorption isotherm. The free adsorption energy and the influence of temperature on the inhibitor adsorption onto mild steel surface have been reported. Calculated $$\Delta G_{{{\text{ads}}}}^{^\circ }$$ values confirm that the adsorption mechanism of this inhibitor on mild steel in 0.5 M H2SO4 solution is a chemical adsorption. The quantum chemical calculations were applied to elucidate adsorption pattern of inhibitor molecules on the steel surface.

Three imidazole ionic liquids as green and eco-friendly corrosion inhibitors for mild steel in sulfuric acid medium

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]Br2) was investigated for mild steel (MS) in H2SO4 medium via experimental and theoretical methods. The results of electrochemical experiments show that the order of their corrosion inhibition is [BMImB]Br2 > [APMIm]Br > [PrMIm]Br. The corrosion inhibition efficiency of [BMImB]Br2, [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]Br2 has higher corrosion inhibition performance for [APMIm]Br and [PrMIm]Br. Weight loss experiments show that [BMImB]Br2 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.

Cetyl Trimethyl Ammonium Bromide as Anti-Pit Agent for Mild Steel in Sulfuric Acid Medium

Aim: Pitting corrosion is a very serious problem for mild steel when it comes in contact with the dilute sulfuric acid medium. Specialized corrosion inhibitors are essentially required to minimize pitting and uniform types of corrosion in mild steel. Background: Most of the corrosion inhibitors discovered so far protects the mild steel from uniform type of corrosion. But pitting corrosion is more fatal than a uniform type of corrosion because it immediately makes mild steel unfit for use as leakage starts from the pit. Objective: The objective was to protect the mild steel alloys from pitting corrosion when comes in contact with dilute sulfuric acid by the use of organic corrosion inhibitor. Methods: Cetyl Trimethyl Ammonium Bromide (CTAB) is tested as a corrosion inhibitor for mild steel in 0.1 N H2SO4 as corroding medium at 25.0, 30.0 and 35.0°C by weight loss, electrochemical polarization, and Impedance spectroscopy methods. Surface study of corroded and un-corroded specimens of mild steel was carried out by Metallurgical Research Microscopy (MRM) and Scanning Electron Microscopy (SEM) techniques. Results: Surface study confirms that the adsorption of CTAB takes place through nitrogen atom resulting in the formation of uniform, nonporous, passive film confirmed by decrease in Warburg Impedance (Zw), decrease in Faradaic current, increase in Capacitive current, an increase in charge transfer resistance, Rct (41 to 401 Ω cm2) and significant increase in capacitive loop in Nyquist plot with increase in concentration of CTAB which results in significant decrease in corrosion rate of mild steel in 0.1N H2SO4 medium (percentage corrosion inhibition efficiency: 95.0%) especially eradicating pitting type of corrosion. Conclusion: CTAB was proved to be a very good anti-pit agent for mild steel in 0.1N sulfuric acid medium. Pitting and uniform type of corrosion was significantly reduced by the use of CTAB as corrosion inhibitor for mild steel in the dilute sulfuric acid medium at 25.0, 30.0 and 35.0°C.

A new insight into corrosion inhibition process of mild steel in sulfuric acid medium: a combined experimental and theoretical study

Purpose This study aims to investigate the inhibition effect of a newly synthesized1,2,3-triazole containing a carbohydrate and imidazole substituents, namely, 1-((1-((2,2,7,7-tetramethyltetrahydro-5H-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl)-1H-benzo[d]imidazole (TTB) on the corrosion of mild steel in aerated 1 M H2SO4. Design/methodology/approach The authors have used weight loss measurement, potentiodynamic polarization, electrochemical impedance spectroscopy, FT-IR studies, scanning electron microscopy analysis and energy dispersive X-ray (EDX) spectroscopy techniques. Findings It is found that, in the working range of 298-328 K, the inhibition efficiency of TTB increases with increasing concentration to attain the highest value (92 per cent) at 2.5 × 10−3 M. Both chemisorption and physisorption of TTB take place on the mild steel, resulting in the formation of an inhibiting film. Computational methods point to the imidazole and phenyl ring as the main structural parts responsible of adsorption by electron-donating to the steel surface, while the triazol ring is responsible for the electron accepting. Such strong donating–accepting interactions lead to higher inhibition efficiency of TTB in the aqueous working system. Originality/value This work is original with the aim of finding new acid corrosion inhibitors.

Corrosion inhibition properties of 4-methyl-2-(methylthio)-3-phenylthiazol-3-ium iodide on the carbon steel in sulfuric acid medium

Weight loss measurement and electrochemical techniques were used as the methods for studying the inhibition effects of 4-methyl-2-(methylthio)-3-phenylthiazol-3-ium iodide (ST1) on carbon steel corrosion in 0.5 M H2SO4. The results reveal that corrosion rate of carbon steel decreases with addition of ST1 in 0.5 M H2SO4. The corrosion rate and inhibition efficiency were found to depend on the concentration of the inhibitor. Inhibition efficiencies up to 99% can be obtained. The polarization data indicated that the inhibitor was of mixed type, with predominant effect on the cathodic partial reaction. Changes in impedance parameters (charge transfer resistance, Rt, and double layer capacitance, Cdl) confirm that corrosion inhibition was due to adsorption on the metal surface following the Langmuir adsorption isotherm. The results obtained from the three different techniques were in good agreement. The influence of the immersion time shows that the inhibiting molecules form a stable and efficient film. XPS analyses clearly show that the adsorption mechanism of ST1 on the carbon steel surface in 0.5 M H2SO4 solution is mainly physical adsorption.

AN ELECTROCHEMICAL STUDY FOR CORROSION INHIBITION OF IRON BY A DERIVATIVE OF ORGANIC PHOSPHONIUM HALID IN ACID MEDIA

Steel and its alloys have many industrial applications, especially in the chemical, thermal, nuclear and, recently, in the petroleum industry. Therefore the study of corrosion and corrosion inhibition of this metal is a very important subject. This work describes the study of the corrosion behavior of XC 70 steel in sulfuric acid medium and the evaluation of the protective power of a series of synthesized compounds such as methyltriphenylphosphonium iodide3. The study was carried out using the Tafel straight line method and electrochemical impedance spectroscopy. The results obtained show that methyltriphenylphosphonium iodide (8) is a very effective mixed inhibitor and reaches a maximum of 83.71% at C = 30 M and for the rotational state of 1500 rpm. The inhibitory efficacy of this compound reaches a maximum of 97.80 at C = 60 M and the results indicate that adsorption is chemisorption following Langmur.

The Effect of Corsican Poplar Leaf Buds (Populus nigra var. italica) Essential Oil on the Tribocorrosion Behavior of 304L Stainless Steel in the Sulfuric Medium

The current study presents for the first time the tribocorrosion behavior of AISI 304L stainless steel in sulfuric acid medium (0.5 M) in the absence and presence of Populus nigra var. italica propolis (PP) essential oil. The results show that in the presence of 600 ppm of PP essential oil a low value of friction coefficient and the dissipated energy are observed, which suggest that the addition of studied essential oil (600 ppm) gives a lubricant aspect to H2SO4 environment. By using the scanning electron microscopy and energy-dispersive X-rays (SEM–EDX), it is clear that the surface is remarkably improved in the presence of P. nigra var. italica propolis essential oil compared to the one exposed to the acid medium without essential oil. From the proprieties of P. nigra var. italica propolis essential oil and the obtained results, it can be suggested that this essential oil is new natural substances that can be used against material wear in aggressive solutions in the presence of a mechanical effect.

Evaluation of the Catalytic Activities of Some Synthesized Divalent and Trivalent Metal Complexes and Their Inhibition Efficiencies for the Corrosion of Mild Steel in Sulfuric Acid Medium

The divalent copper, cobalt, nickel and cadmium in addition to the trivalent iron complexes of the ligand named (E)-1-((4,6-dimethylpyrimidin-2-ylimino)methyl)naphthalen-2-ol were synthesized by the reaction of the ligand with different metal chlorides. The Structures and geometry of the metal chelates have been successfully deduced applying various analytical and spectroscopic tools such as elemental analysis, molar conductance, TGA, magnetic moment measurements, IR, 1H-NMR, EI-mass and UV–Vis spectral studies. The X-ray single crystal structure of the ligand has been also discussed. Spectral studies and analytical results supported the monobasic bidentate behavior of the ligand connecting the metal ion centers via deprotonated phenolic OH and imine nitrogen. In the case of Cu(II) complex, the pyrimidine nitrogen took part in coordination to the Cu center. The results ensured the monometallic character of the chelates having 1:2 (M:L) ratio for copper, cobalt and nickel and 1:1 (M:L) ration for iron and cadmium complexes. The molar conductance data ensured that all the metal complexes are non-electrolytic type of complexes. All the complexes have been proved to have octahedral geometry. The antimicrobial activities of the synthesized metal chelates were evaluated against different bacterial and fungal strains. The synthesized ligand and its complexes were also examined as inhibitors for the corrosion of mild steel in 1.0 M H2SO4 at 25 °C using various techniques. The experimental outcomes indicated that the inhibition efficiencies of the tested compounds increased as their concentrations increase. The obtained inhibition efficiencies were interpreted on the basis of strong adsorption of the inhibitor molecules on the surface of mild steel and composing good protection films. The adsorption was found to obey Langmuir adsorption isotherm. The results achieved from all applied techniques are obviously compatible.

Cysteamine modified polyaspartic acid as a new class of green corrosion inhibitor for mild steel in sulfuric acid medium: Synthesis, electrochemical, surface study and theoretical calculation

In the present work, an attempt has been made for the development of green and high efficiency acid pickling inhibitor based on the eco-friendly polyaspartic acid (PASP). In this view, cysteamine modified PASP (PASP-S) containing S atom was prepared by ring-opening reaction of polysuccinimide with cysteamine. The corrosion inhibition performance of PASP and PASP-S for mild steel in 0.5 M H2SO4 medium were evaluated using weight loss, electrochemical impedance and potentiodynamic polarization methods. The inhibition performance of PASP-S is greatly improved with a high efficiency of 93.9% (weight loss method) at a very low concentration of 100 mg L−1 at 298 K in comparison with unmodified PASP. The obtained results also indicate that PASP-S is a mixed inhibitor and the adsorption of PASP-S on the mild steel surface follows Langmuir adsorption isotherm. Theoretical chemical parameters are calculated using the Density Functional Theory method (DFT). The excellent inhibition performance of PASP-S is due to the presence of pendent functional sulfhydryl group, which can be confirmed by X-ray photoelectron spectroscopy (XPS) analysis of the mild steel samples. The present work provides a simple and effective pathway for synthesizing high efficiency acid pickling inhibitor by introducing a functional group into the PASP chains. Such chemical modification method may also be an effective strategy to improve the efficiency of other polymer acid pickling inhibitors.

Corrosion protection of new composite polymer coating for carbon steel in sulfuric acid medium by electrochemical methods

In this paper, electropolymerization technique has been used for the obtained of new composite: polypyrrole – dioctyl sulfosuccinate sodium/poly N-ethylaniline (PPY-AOT/PNEA) coatings over carbon steel of type OLC 45 electrode for anticorrosion protection. The PPY-AOT/PNEA coatings were successfully synthesized onto OLC 45 electrode by galvanostatic deposition from aqueous solutions 0.1 M NEA, 0.1 M PY, 0.01 M AOT and 0.3 M H2C2O4 solution at different current densities (5, 3 and 1 mA/cm2) in different molar ratio. The anionic surfactant (AOT) as a dopant ion used during electropolymerization can have a significant result on the anticorrosion protection of the composite film by hindering the penetration of aggressive ions. The polymeric composite coatings have been analyzed by cyclic voltammetry (CV), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) methods. The corrosion resistance of PPY-AOT/PNEA coated carbon steel has been examined by potentiodynamic polarization techniques and electrochemical impedance spectroscopy (EIS) methods in 0.5 M H2SO4 solutions. The data of the corrosion samples demonstrated that PPY-AOT/PNEA coatings assure a great anticorrosion protection of OLC 45 electrode in corrosive media. The corrosion rate of PPY-AOT/PNEA coated OLC 45 has been indicated to be ~9 times lower than of uncoated electrode. The corrosion protection effectiveness of the composite coating is more than 89%. The best efficiency is accomplished of PPY-AOT/PNEA obtained by electrodeposition at 5 mA/cm2 current densities applied in molar ratio 5:1.

Benign Approach of Plant-Derived Inhibitor: Assessing Their Anticorrosive Activity on Mild Steel in Acidic Media

The dissolution behavior of mild steel in 2 M H2SO4 with various concentrations of Borassus Flabellifer Seed Food (BFSF), Musa Paradisiaca Dry Leaf (MPDL), and Saccharum Officinarum Bagasse (SOB) was evaluated using both mass loss and electrochemical methods. It is evident from the results that the biomaterial extracts could be precious inhibitors for the corrosion of mild steel in sulfuric acid media. The inhibition efficiency of the tested inhibitors enhanced with increase in BFSF, MPDL, and SOB concentrations but diminished with increasing temperature. The free energy of the adsorption, apparent activation energy, enthalpy, and entropy of the dissolution process were discussed at 35–60 °C. Impedance curves showed that the charge transfer resistance increased and double-layer capacitance decreased with increase in concentration of tested inhibitors. Scanning electron microscope images revealed that the damage of mild steel surface has diminished in the presence of BFSF, MPDL, and SOB.

Electrochemical and Corrosion Protection Performance of New Polymer Composite Coatings on Carbon Steel in Sulfuric Acid Medium

In this study, galvanostatic electrodeposition mode was used for the synthesis of new composite (Ppy-AOT/PNEA and PNEA/ Ppy-AOT) coatings onto carbon steel of type OLC 45 for corrosion protection. Monolayer poly (N- ethylaniline) (PNEA), polypyrrole (Ppy), dioctyl sulfosuccinate sodium (AOT) and bilayer PNEA/Ppy-AOT and Ppy-AOT/PNEA coatings have been electropolymerization onto carbon steel by galvanostatic synthesis techniques from aqueous solutions 0.1 M N ethylaniline, 0.1M pyrrole, 0.01 M dioctyl sulfosuccinate sodium (AOT) and 0.3 M oxalic acid. In order to include dioctyl sulfosuccinate ions as dopant in the polypyrrole, AOT was also added to the polymerization solution of polypyrrole. The monolayer and bilayer polymers coatings were characterized electrochemically, spectroscopically and morphologically by cyclic voltammetry, Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) techniques. Corros ion behaviour of PNEA-AOT/PPY coated carbon steel of type OLC 45 was investigated by potentiostatic and potentiodynamic polarization, open circuit potential measurements and electrochemical impedance spectroscopy (EIS) techniques in 0.5M and 1 M H2SO4solutions. The results of the corrosion tests showed that PNEA/PPY-AOT coatings ensure good corrosion protection of carbon steel in aggressive media. Bilayer coatings revealed better corrosion protection efficiencies than monolayer coatings. The new complex nanostructured composite obtained from this process is promising and might lead to industrial applications in the protection of the carbon steel substrates against corrosion. Keywords: nanocomposite films, galvanostatic electrodeposition, corrosion protection, SEM, EIS, FT-IR