Protection Of Mild Steel Research Articles

Investigation on corrosion inhibition and adsorption mechanism of triazine-thiourea derivatives at mild steel / HCl solution interface: Electrochemical, XPS, DFT and Monte Carlo simulation approach

Abstract The corrosion inhibition behavior of synthesized triazine-thiourea compounds, namely, 1,3-bis(5,6-diphenyl-1,2,4-triazin-3-yl)thiourea (BTT) and 1,3-bis(5H-[1,2,4]triazino[5,6-b]indol-3-yl)thiourea (BTI) on mild steel in 15% HCl solution was investigated by using gravimetric and electrochemical corrosion testing methods at different experimental conditions. BTT was found more efficient corrosion inhibitor than BTI. It was observed from experimental outcomes that at optimum concentration (200 ppm) and 303 K temperature, BTT was 98.5% efficient towards the corrosion protection of mild steel in 15% HCl solution. The surface morphological study of uninhibited and inhibited samples was performed by FESEM and AFM analysis. Adsorption of both inhibitor molecules on the surface of mild steel obeyed Langmuir adsorption isotherm. XPS analysis was performed to determine the binding energy and elemental composition of adsorbed inhibitor molecules on the surface of mild steel. DFT and Monte Carlo simulation (MCS) was performed to get more insight into the protection mechanism adopted by inhibitor molecules.

Extended protection of mild steel in saline and acidic environment using stearic acid grafted chitosan preloaded with mesoporous-hydrophobic silica (mhSiO2)

This study produces an enhanced anti-corrosion property of chitosan-based film on mild steel (MS) in different aggressive media using surface modified SiO2. Mesoporous hydrophilic SiO2 is rendered hydrophobic by using silylating agent hexamethyl disilazane (HMDS). The incorporation of 3.0 weight percentage surface-modified silica into the chitosan matrix and further grafting with stearic acid (SA) through 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) mediated coupling reaction improve the anti-corrosion properties of the coating on mild steel. The resulting chitosan-based film was characterized by FTIR, TGA, AFM, FESEM, and EDX techniques. The film formed was applied for corrosion protection of mild steel in 0.5 M HCl and 3.5% NaCl and analyzed via non-electrochemical and electrochemical techniques.

Portulaca grandiflora as new green corrosion inhibitor for mild steel protection in hydrochloric acid: Quantitative, electrochemical, surface and spectroscopic investigations

The inhibition action of the Portulaca grandiflora leaf (PGL) extract against corrosion on N80 carbon steel was tested under 0.5 M HCl acidic conditions at variable temperatures and inhibitor concentrations. The performance behaviour of PGL was evaluated by weight loss and electrochemical techniques including polarisation measurement, open circuit potential, and electrochemical impedance spectroscopy. The analysis results of Fourier transform infrared spectroscopy, ultraviolet spectra, and surface morphology strongly support the corrosion rates results. The obtained outcomes show that the inhibitor can effectively inhibit the corrosion of carbon steel in acidic media with a maximum inhibition efficiency of 95% at high levels of temperature (60 °C) and inhibitor concentration (20 mL/L). The adsorption of PGL on the steel surface followed that according to the Langmuir isotherm model. The heat of adsorption values increased from -17.71 kJ mol-1 to -22.03 kJ mol-1 as the temperature increased from 30 to 60°C suggests a mixed-mode of adsorption on the metal surface.

Superior potentials of hydrazone Schiff bases for efficient corrosion protection of mild steel in 1.0 M HCl

Steel is usually cleaned by acid solutions before its application in various industries. Such a treatment increases the possibility of steel corrosion, making the use of inhibitors in the cleaning bath indispensable. On this basis, the introduction of novel, efficient corrosion inhibitors is always of great importance. In the present research, three series of hydrazone Schiff bases were synthesized and investigated as corrosion inhibitors for mild steel in 1.0 M HCl solution. Corrosion experiments included weight loss, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP), which were performed at different temperatures. SEM images provided the surface analysis of the steel sheets in the absence and presence of the inhibitors. The prepared Schiff bases exhibited inhibition efficiencies higher than 92% at an optimum concentration of 0.01 M. The quantitative structure–activity relationship (QSAR) was used to obtain a correlation between the inhibition efficiency and the quantum chemical parameters of the inhibitors.

Lemon seeds as green coating material for mitigation of mild steel corrosion in acid media: Molecular dynamics simulations, quantum chemical calculations and electrochemical studies

Natural materials are the subject of high priority for corrosion scientists, now a day. Various natural materials have been used to date for corrosion protection of metals. However, their utilizations have been done either in inhibition (mostly) or coating applications (only in composite form). In present work, lemon seed (alone) is used for inhibition as well as coating protection of mild steel (MS) corrosion in acid media. Aqueous extract of lemon seed (ALS) is used as inhibitor, whereas chloroform extract of lemon seed (CLS) is used to form wet (CLSW) and dry (CLSD) coating on MS substrate. Characterizations of ALS, CLSW and CLSD have been done by UV–visible spectroscopy, FTIR spectroscopy, HRSEM, EDAX and AFM analysis. Corrosion testing of both extracts has been performed in 1 M HCl by ac impedance measurements (AIM) and Tafel polarization curves (TPC). The results show that ALS gives very low inhibition of MS corrosion (~45%), while MS coated with CLSD/CLSW provide high efficiency protection (~98%) to the substrate. Theoretical analysis tools, i.e., molecular dynamics simulations and quantum chemical calculations, are also used to determine corrosion properties of lemon seed molecule, which suggest that lemon seed can be prominent material for prevention of MS corrosion.

Excellent protection of mild steel in sodium chloride solution for a substantial period of time using a hybrid nanocoating of poly vinyl alcohol and Titania

The production of eco-friendly hybrid sol–gel coatings for long term protection of metallic substrates from aggressive environments was one of the emerging areas, competing with conventional chromate and phosphate coatings. Herein, a nanocomposite has been synthesized from TiO2 and PVA through a novel sol-gel route and the structure and morphology of the same was characterized using X-ray diffraction, FTIR, UV–Vis spectroscopy, FESEM with EDAX, and AFM studies. The flower-like structured composite offers excellent corrosion protection properties in NaCl solution of sea water salinity. Impedance and polarization studies were carried out to monitor the anticorrosion performance of the materials coating. This coating on mild steel offers 98% inhibition efficiency in NaCl. The influence of loading PVA on TiO2 and its effect on corrosion efficiency have also been investigated. It is found that an optimum weight of 20 wt% PVA is required in the composite for beneficial corrosion resistance. 92% inhibition efficiency is registered by the coated MS in NaCl solution after 40 days of exposure and is quite encouraging compared to many of the recent reports. The Ti–O–Ti, and Fe-Ti-O linkage along with compactness and adherence of the material together contribute to better blocking of steel corrosion.

Green-based corrosion protection for mild steel in 3.5 % NaCl and distilled water medias: Jatropha curcas and Roselle extracts

In this study, the natural sources of Jatropha curcas and Hibiscus Sabdariffa calynx (Roselle) extracts as green corrosion inhibitors were employed to improve the corrosion resistance of mild steel in simulated (3.5% NaCl) and distilled water medias. The inhibiting performance of two types of extracts was studied by visual inspection, microscope analysis, and various electrochemical measurements and the data of corrosion rate were statistically analyzed. The main phenolic compounds of Jatropha and Roselle extracts were confirmed via a liquid chromatography-mass spectrometry. Meanwhile, the functional groups of active phytochemical compounds were characterized via attenuated total reflection spectroscopy (ATR). The results of different electrochemical tests were revealed that the additions of Jatropha and Roselle extracts into the corrosion solution have an efficient corrosion inhibitor in reducing the corrosion rate though forming an adsorptive protective film on the surface, which reduced contact between samples’ surfaces and solution medium and ultimately reduced corrosion attack. Practically, Jatropha extract showed the highest inhibitive efficiencies compared to Roselle extract in both simulated water and 3.5% NaCl solutions.

Extracts of curcumin-incorporated hybrid sol–gel coatings for the corrosion mitigation of mild steel in 0.5 M HCl

Curcumin was extracted from turmeric using two solvents (ethanol and water), doped with hybrid (TEOS-APTES) sol–gel coatings for the corrosion protection of mild steel. Characterization of curcumin extracts was carried out using integral analyses, namely FTIR, NMR, DSC, TGA, total phenolic content, and antioxidant assay. Corrosion-inhibitive ability of coatings doped with curcumin extracts (25, 50, 75, and 100 ppm) were evaluated via electrochemical impedance spectroscopy and potentiodynamic polarization measurements. It was evident that sol–gel incorporated with 100 ppm ethanol extract provided more than 90% of inhibition efficiency. Coated mild steel surfaces were characterized using FTIR, SEM/EDX, and water contact angle analysis where coatings incorporated with curcumin extracts were found to be hydrophobic (θ = 100.2°).

Polyethylenimine wrapped mesoporous silica loaded benzotriazole with high pH-sensitivity for assembling self-healing anti-corrosive coatings

The aim of this work is to develop a self-healing coating doped with pH-sensitive nanocontainers for the active corrosion protection of mild steel. A pH-sensitive carboxyl-functionalized mesoporous silica nanomaterials (MSNs-COOH) was prepared via chemical modification of mesoporous silica nanomaterials (MSNs) which was synthesized in a tetraethyl orthosilicate (TEOS) solution via base catalyzed sol-gel process. Benzotriazole (BTA) molecules were loaded into the internal pores of the prepared MSNs-COOH. Then the BTA-loaded MSNs-COOH were wrapped by the highly branched polyethylenimine (PEI) to obtain the nanocontainers of BTA@MSNs-COOH-PEI. SEM, TEM, DLS, XRD, nitrogen adsorption-desorption isotherms, TGA and FT-IR analyses were employed to characterize the as-prepared nanocontainers. The pH-sensitive releasing property of BTA@MSNs-COOH-PEI was studied using UV–vis spectroscopy, which indicates that the releasing rate of BTA from BTA@MSNs-COOH-PEI can be accelerated under alkaline conditions. Afterwards, a self-healing coating was fabricated based on the epoxy resin primer doped with BTA@MSNs-COOH-PEI which can release BTA inhibitor once localized corrosion occurs. Finally, the active anti-corrosion performance of the as-prepared coating was confirmed by EIS measurements and salt spray tests. The self-healing coating prepared in this work brings a new sight for elaborate design of active anti-corrosion coatings.

Impact of selected ionic liquids on corrosion protection of mild steel in acidic medium: Experimental and computational studies

The corrosion potential of three newly studied ionic liquids (ILs) namely, 5-(Trifluoromethyl) dibenzothiopheniumtetrafluoroborate (TDTB), 5-(Trifluoromethyl)dibenzothiopheniumtrifluoromethanesulfonate (TDTM) and 1-Ethyl-3-methylimidazolium ethyl sulfate (EMIM)(ESO4) were investigated for mild steel (MS) in 1 M hydrochloric acid using electrochemical, Fourier trans­form in­frared (FTIR) spec­troscopy and gravimetric tech­niques. The potentiodynamic polarization data shows that the three inhibitor molecules studied possess characteristics that correspond to mixed-type inhibitors but TDTM exhibits more anodic characteristics. Scan­ning electron microscopy (SEM) was used for the surface studies. Remarkable corrosion inhibition of mild steel was also predicted using energy dispersive spectroscopy (EDS). FTIR spectroscopy established the functional group interrelationship showing disappearance of characteristic absorption bands in the adsorption film FTIR spectra. Quantum chemical calculations and Monte Carlo mod­els were utilized to gain more in­sight into the electronic properties of the compounds in rela­tion to the corrosion inhibition effect and the binding and/or adsorption of ionic liquids on the surfaces of MS. The adsorption en­ergy adopts the order: TDTB ≈ TDTM >(EMIM)(ESO4). The numerical val­ues of adsorption energy is −3.72 kcal mol−1, −3.77 kcal mol−1 and −3.04 kcal mol−1 for TDTB, TDTM and (EMIM)(ESO4), respectively.

Investigation on corrosion protection behavior and adsorption of carbohydrazide-pyrazole compounds on mild steel in 15% HCl solution: Electrochemical and computational approach

The behavior of synthesized (E)-5-amino-3-(4-methoxyphenyl)-N′-(1-(4-methoxyphenyl)ethylidene)-1H-pyrazole-4-carbohydrazide [AMPC] and (E)-5-amino-N′-(4-chlorobenzylidene)-3-(4-chlorophenyl)-1H-pyrazole-4-carbohydrazide [ACPC] towards the corrosion protection of mild steel (MS) in 15% HCl solution was studied by gravimetric and electrochemical methods. The inhibitor AMPC and ACPC at an optimum concentration of 300 ppm showed 98.26% and 96.21% inhibition efficiency, respectively at 303 K temperature. Thermodynamic results conquer that both inhibitors followed mixed adsorption and results from polarization suggests the retardation of the cathodic as well as anodic reactions in presence of inhibitors. The Langmuir adsorption isotherm suggests the monolayer adsorption of inhibitors on the MS facet. The formation of protective layers of inhibitors on MS surface was confirmed by the outcomes of FESEM and AFM topographical details. The composition of adsorbed layers on the MS surface was studied by XPS analysis. The energy related to molecular orbital of inhibitors, and adsorption behavior was computationally examined by Density Functional Theory (DFT), calculation of Fukui functions and Monte-Carlo simulation (MCS) studies.

Corrosion Protection of Mild Steel by a New Phosphonated Pyridines Inhibitor System in HCl Solution

The adsorption behavior and inhibition mechanism of (1, 4, 7-Tris [hydrogen (6-methylpyridin-2-yl) phosphonate] -1, 4, 7-triazacyclononane) (TPP) on the corrosion of mild steel in 1 M HCl were investigated by weight loss technique, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) methods for different concentrations at 25°C. The results show that the inhibition efficiency values depend on the amount of immersion times and the concentration. A 90% efficiency is found at the highest concentration of the studied compound according to weight loss measurements. The adsorption of the investigated inhibitor on the mild steel surface was well supported using an AFM study. For the assignment of the absorption sites, we performed quantum chemical calculations with (DFT) method. The interaction between the inhibitor and iron surface were performed by molecular dynamic (MD) simulations. In this paper, experimental methods and results used to assess the efficiency of the studied compound are presented.

Development of self-assembled monolayer of stearic acid grafted chitosan on mild steel and inhibition of corrosion in hydrochloric acid

Abstract Chitosan (CS) based systems are extensively used as a green alternative for corrosion protection of mild steel (MS) possessing good film-forming properties, chelation with metal and nontoxic nature. In this study, a self-assembled monolayer of stearic acid grafted chitosan was developed via 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide mediated coupling reaction and casted on the MS surface. From the fluorescence intensity of the fluorescent probe pyrene, the critical micelle concentration (66 μg/mL) of self-aggregates in aqueous solution was determined. The purified chitosan grafted films were characterized by apposite analytical techniques. The film developed was employed for corrosion protection of MS in 0.5 and 1 N HCl via electrochemical and non-electrochemical techniques. The results showed that stearic acid grafted chitosan (CSA) films do offer better corrosion protection to MS than bare CS film.

Synergistic Study of Modified Sweet Potato Starch and KI for Corrosion Protection of Mild Steel in Acidic Media

Native starch (NS) extract from sweet potato was modified by alkaline treatment. The alkaline modified starch (AMS) and NS were characterized and assessed as corrosion inhibitor of mild steel under acidic conditions by gravimetric and potentiodynamic polarization techniques. Results obtained indicate that AMS exhibited higher inhibition efficacy that was stable over time. Synergistic use of potassium iodide improved the inhibitive efficacy of AMS. Polarization data propose that AMS operated via a mixed-inhibition mechanism and the experimental adsorption data followed Langmuir isotherm. The adsorption of AMS on the metals was established by Fourier transform infrared spectroscopy and Atomic force microscopy.

Fructan from Polygonatum cyrtonema Hua as an eco-friendly corrosion inhibitor for mild steel in HCl media

An effective and biodegradable polygonatum fructan (PF) from Polygonatum cyrtonema Hua was studied as an eco-friendly corrosion inhibitor for mild steel protection in 1 M HCl, whose inhibition performance was studied by weight loss tests, electrochemical techniques, and surface analysis techniques (SECM, FTIR). The experimental results showed that PF has outstanding inhibition performance for mild steel in hydrochloric acid, and the inhibition efficiency increased with the increase of its concentration and temperature. Polarization studies indicated that PF is a mixed-type corrosion inhibitor, and its adsorption mode conforms to Langmuir isotherm, mainly chemisorption. An adsorption-related protective inhibitor film formed on the surface of mild steel was verified and investigated based on its surface analysis and characterization. Quantum chemical analysis showed that the adsorption of PF on the surface of mild steel has obvious chemical properties.

Investigation of 2,2′-diaminodiethyl disulfide for mild steel protection in acid solution

Inhibition performance of 2,2′-diaminodiethyl disulfide (DA) was studied against mild steel (MS) corrosion in 0.5 M HCl. Electrochemical impedance spectroscopy (EIS), potentiodynamic (PD) polarization measurements were utilized to investigate the influence of inhibitor concentration and temperature on efficiency, as well as explanation of inhibition mechanism. Scanning electron microscopy (SEM) analysis was utilized to investigate the surface damages due to corrosion, in the absence and presence of inhibitor molecules. PD data revealed that the studied molecule exhibits mixed type inhibitor behavior on steel surface. Moreover, the calculated free adsorption energy (ΔGadso) value is 38.45 kJ mol−1, which indicates to strong adsorptive interaction by both physical and chemical means. UV–Visible study results supported the idea that there is strong interaction between the surface with the molecule, via its –S and –N atoms. As a consequence, 91.7% inhibition efficiency was determined in presence of 1.0 mM DA.

Aloe polysaccharide as an eco-friendly corrosion inhibitor for mild steel in simulated acidic oilfield water: Experimental and theoretical approaches

Abstract An effective and biodegradable aloe polysaccharide (APS) was studied as an eco-friendly corrosion inhibitor for mild steel protection in simulated acidic oilfield water (15% HCl), whose inhibition performance was studied by weight loss tests, electrochemical techniques, and surface analysis techniques (SEM, EDX, AFM). The experimental results showed that APS has an outstanding inhibition performance for mild steel in 15% HCl, and exhibited a good inhibitory activity over a wide temperature range. Polarization studies indicated that APS is a mixed-type corrosion inhibitor, and its adsorption mode conforms to Langmuir isotherm. An adsorption-related protective inhibitor film formed on the surface of mild steel was verified and investigated based on its surface analysis and characterization. Quantum chemical calculations and molecular dynamics (MD) simulations were performed for the major monosaccharide components of APS to detect structural adsorption behavior.

Sodium sulfite as an oxygen scavenger for the corrosion control of mild steel in petroleum refinery wastewater: optimization, mathematical modeling, surface morphology and reaction kinetics studies

Corrosion protection of mild steel in simulated refinery wastewater solution (2 wt% MgCl2) by sodium sulfite, as oxygen scavenger inhibitor type, was studied at different temperatures, inhibitor concentrations, rotational velocities and exposure times using weight loss and electrochemical techniques. Oxygen concentrations were also monitored at initial and final conditions. The corrosion inhibition process was optimized by 24 full factorial experimental designs. Optimum conditions of minimum corrosion rate were 40 °C, 40 ppm, 1250 rpm, and 6 h for temperature, inhibitor concentration, rotational velocity, and exposure time. Oxygen levels were reduced by the addition of the scavenger. The amount of oxygen reacted and removed during the corrosion process was evaluated and mathematical relationships were obtained. Electrochemical measurements showed that the corrosion potential shifted to the more active direction and corrosion current decreased with the addition of scavenger. Surface morphology investigations proved that the addition of SS prevents the steel surface damages.

Microstructure and Corrosion Behavior of Aluminum Coatings Prepared by High-Efficiency Supersonic Plasma Spraying and Oxygen–Acetylene Flame Spraying

Thermal spraying aluminum coatings have been widely used in the corrosion protection of mild steel in seawater. In this study, high-efficiency supersonic plasma spraying (HESP) and oxygen–acetylene flame spraying (FS) were used to prepare aluminum coatings. The micromorphology of the coatings was analyzed by a scanning electron microscope equipped with an energy-dispersive x-ray spectrometer. The phase identification of the coatings was conducted by an x-ray diffractometer. The Vickers hardness and bonding strength of the coatings were measured by an HMV-2000 Vickers hardness tester and MTS809 universal tensile tester. The corrosion resistance of the coatings was tested by an IM6ex electrochemical workstation. The results show that the aluminum coatings prepared by HESP have a denser structure, higher microhardness, higher bonding strength, and better corrosion resistance than those prepared by the traditional FS. After 480-h immersion in 3.5 wt.% NaCl solution, a dense corrosion product formed on the surface of aluminum coatings prepared by HESP prevents further corrosion of the coatings, but the aluminum coatings sprayed by FS demonstrate a serious pitting phenomenon.

Dardagan Fruit extract as eco-friendly corrosion inhibitor for mild steel in 1 M HCl: Electrochemical and surface morphological studies

Abstract In this study, Dardagan Fruit (DF) from Bingӧl - Turkey was tested as inhibitor corrosion for mild steel protection in 1 M HCl solution using electrochemical techniques. The surface of mild steel was examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Elemental composition of the surface after exposing to test solutions was analyzed with the help of energy dispersive X-ray spectroscopy (EDX). Contact angle measurements were also performed to get information about the surface properties. Spectroscopic studies were performed to determine major components, chemical structure and adsorption mechanism of the extract. The excess surface charge of mild steel was determined using electrochemical impedance spectroscopy (EIS) and an inhibition mechanism was proposed. It was found that DF has good corrosion protection ability. The inhibition of corrosion rate reduces when concentration of DF and exposure time are increased and reaches 92% after 1 h and 97% after 6 h immersion to 3000 ppm inhibitor containing corrosive media. The high protection ability was assigned to formation of a homogenously distributed protective film over the metal.