Corrosion Inhibition Of Stainless Steel Research Articles

Electrochemical and Quantum Chemical Investigations of novel pyrazole derivatives as a Corrosion Inhibitor for Stainless Steel in 2M H2SO4 medium

Stainless steels play a crucial role in diverse industrial domains. However, due to their exposure to acidic environments, stainless steels undergo the corrosion phenomenon, leading to the deterioration of the material and its properties. Thus, the objective of this work is to study the corrosion inhibition of stainless steel in an H2SO4 2M medium by using two organic compounds, namely Py-3:{1-amino-5,10-dioxo-3-(p-tolyl)-5,10-dihydro-1H-pyrazolo[1,2-b] phthalazine-2-carbonitrile} and Py-4:{1-amino-3-(2-chlorophenyl)-5,10-dioxo-5,10-dihydro-1H-pyrazolo[1,2-b]phthalazine-2carbonitrile}. This study was conducted using transient electrochemical methods in conjunction with a theoretical approach. The obtained results demonstrate that the addition of pyrazole compounds in the corrosive medium H2SO4 exhibits excellent inhibitory power against steel corrosion, with an inhibitory efficiency reaching 98%. The tested inhibitors are adsorbed into the surface of the metal by chemical bonds, Moreover, the adsorption of these compounds follows the Langmuir adsorption model. Theoretical calculations based on the Density Functional Theory (DFT) provide a better understanding of the reactivity of tested inhibitor towards stainless steel which they are in good agreement with the experimental findings.

Corrosion Inhibition of Stainless Steel in 1.0 M Hydrochloric Acid Solution Using Novel Nonionic Surfactant: Electrochemical and Density Functional Theory/B3LYP/6-31G* Analysis

Corrosion Inhibition of Stainless Steel in 1.0 M Hydrochloric Acid Solution Using Novel Nonionic Surfactant: Electrochemical and Density Functional Theory/B3LYP/6-31G* Analysis

Beneficial Effects of Cerium Addition to Sulfide Inclusions on Pitting Corrosion Resistance of Stainless Steels

The pit initiation sites for commercial stainless steels have been attributed to sulfide inclusions such as MnS. The chemical composition of the inclusions affects the pitting corrosion resistance of stainless steels. It is known that the inclusion solubility in aqueous solutions affects pitting corrosion resistance. The dissolution of sulfide inclusions produces S species and exposes the bare surface of the steel matrix, resulting in high pitting susceptibility near the inclusions.1 Cerium is expected to be an additive element for insolubilizing water-soluble inclusions because Ce tends to form sulfides and Ce-sulfides exhibit low solubility in aqueous solutions. Additionally, Ce ions have been shown to be effective in the corrosion inhibition of stainless steel. In this study, a microelectrochemical technique was applied to analyze the effect of Ce addition to sulfide inclusions on the pitting corrosion resistance of stainless steels.2,3 To analyze the effect of Ce addition on water solubility of CaS inclusions, spark plasma sintering was used in the facile fabrication of stainless steel specimens containing artificial Ce-added and Ce-free inclusions.3,4,5 The pit initiation resistance at the Ce-added CaS inclusions was higher than that at the Ce-free CaS inclusions. The surface of the Ce-free CaS inclusions largely dissolved during immersion in 0.1 M NaCl, while a large part of the Ce-added CaS inclusions remained undissolved. Thermodynamic calculation showed that CeS is less soluble than CaS.To analyze the effect of Ce ions on pitting at sulfide inclusions, a type 304 stainless steel (Fe-18Cr-8Ni-1.5Mn-0.02S) was prepared by vacuum induction melting. Manganese sulfide inclusions existed in the specimens. Polarization curves were measured in 3 M NaCl and 2.97 M NaCl-0.01 M CeCl3. Pitting occurred at the MnS inclusions in the Ce3+-free solution, whereas no stable pit was generated in the Ce3+-containing solution even when metastable pitting events were observed.It was found that Ce addition inhibits the dissolution of water-soluble inclusions and improved pitting corrosion resistance. Moreover, the Ce3+ ions are expected to inhibit the pitting even after the dissolution of Ce-added inclusions.

Thermodynamic and Optimization Studies of Castor Leaf Extract as Corrosion Inhibitor on Stainless Steel (301)

Inhibition of stainless steel corrosion in acidic medium with castor leaf extract was studied using the Gravimetric measurement. The mechanisms of inhibition, influence of temperature on inhibition efficiency and weight loss were determined for temperature range 40 oC – 80 oC at 7 hours immersion time. An increased in temperature showed a decreased in the inhibition efficiency of the castor leaf extract which resulted to increase in weight loss of the stainless steel. The value of rate constant for the corrosion process ranges from 0.333 – 1.225 hr−1, this is seen to be directly relative to the inhibitor concentrations. Activation energy, enthalpy of activation, and entropy values ranges from 74.000 - 136.377 kJ/mol, 71.820 – 133.620 kJ/mol, and 9.860 – 178.110 J/molK respectively. Rise in activation energy with inhibitor concentration confirmed physisorption adsorption mechanism for stainless steel surface corrosion. In order to obtain the optimum weight loss, optimization of the process variables was carried out using the Box – Behnken Design plan and desirability function of response surface methodology (RSM). Four parameters were varied viz; time of immersion, HCl concentration, inhibitor’s concentration, and temperature alongside their effects on weight loss of the stainless steel were verified. The optimal conditions predicted from the second order quadratic model were time (9.10 hours), HCl concentration (3.97 M), concentration of inhibitor (240.90 ppm), and temperature (78.67 oC) with 2.978 g as the weight loss. Statistically, the results showed that 95.03% of the variation in total weight loss of stainless steel can be connected to the experimental variables examined.
 Keywords: Weight loss, activation parameters, adsorption, optimization, stainless steel, castor leaf

The corrosion inhibition of stainless steel by ferrocene–polyoxometalate hybrid molecular materials – experimental and first principles studies

The hybrid molecular materials [Fe(C5H5)2]3[PW12O40]·(H2O)4 and [Fe(C5H5)2]3[PMo12O40]·(H2O)6, denoted respectively as FcPW and FcPMo, are synthesized via a co-precipitation method under acidic conditions (pH: ∼2-3). The molecular properties of these compounds are investigated via various analytical methods. UV-vis diffuse reflectance and photoluminescence studies confirm that these compounds are charge-transfer salts. Stainless steel plates (SS, 316 grade) coated with these hybrid compounds and dipped in 0.5 M H2SO4 and Ringer's solutions show significantly inhibited corrosion. The corrosion inhibition properties of these materials are studied via weight loss, electrochemical impedance spectroscopy, and potentiodynamic polarization studies. The reproducibility of the corrosion inhibition results is ensured via repeat measurements, and error values are reported. The surfaces of the corroded steel plates are examined via scanning electron and atomic force microscopy techniques. It is found that the corrosion is of uniform type. The Tafel extrapolation method shows that the inhibition efficiency is 74% for SS@FcPMo and 65% for SS@FcPW. The corrosion inhibition mechanism is explained based on the redox nature of the hybrid materials. The experimental results are corroborated through computational studies carried out using a first principles approach with the optimized geometries and frontier molecular orbitals of the hybrid molecular materials.

Green approach to corrosion inhibition of stainless steel in phosphoric acid of Artemesia herba albamedium using plant extract

Essential oil from aerial parts of Artemisia herba-alba from Morocco was hydrodistilled and its chemical composition oil was investigated by capillary GC and GC/MS. The major components were 1,8-cineole (35.6%) and camphor (24.1%). Artemisia herba-alba essential oil AHAO was tested as corrosion inhibitor of stainless steel (SS) in 1M H3PO4 using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy measurements (EIS) and scanning electronically microscopy (SEM) studies. The results obtained showed that the essential oil of Artemisia reduces the corrosion rate. Tafel polarization method indicates that the plant extract behaves as a mixed type inhibitor. The inhibition efficiency increased with inhibitor concentration to attain 88% at 1g.L−1 of oil at 298K. Nyquist diagrams obtained from impedance studies provide results confirming the anti-corrosion effect of the studied plant. The temperature effect on the corrosion behavior of (SS) in 1M H3PO4 without and with AHAO at 1g.L−1 was studied in the temperature range from 298 to 353K. Thermodynamic parameters suggested that the adsorption is spontaneous and exothermic process and support physical adsorption mechanism. The experimental data fits well into the Langmuir adsorption isotherm model. SEM/EDS studies provide the confirmatory evidence for the protection of (SS) by the green inhibitor. The results obtained from these methods used are in good agreement.

Corrosion Inhibition of Stainless Steel in HCl Solution Using Newly Aniline and o-Anthranilic Acid Copolymer

This paper introduces copolymers of aniline and o-anthranilic acid with different ratio of aniline/o-anthranilic acid (r = 1, 2 and 3) as novel corrosion inhibitors for stainless steel in high-corrosive media. The synthesized polymers were characterized by Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–Vis) and X-ray diffraction (XRD) techniques. After optimization of the aniline/o-anthranilic acid ratio, the inhibition efficiency of the best copolymer was measured for stainless steel in 2 M HCl solution. Electrochemical methods including potentiodynamic polarization and electrochemical impedance spectroscopy were used in different concentrations of copolymer. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to study the surfaces of the steel after exposed to test solution. It was found that the aniline and o-anthranilic acid copolymer with r = 3 can prevent the penetration of corrosive species into metal surface as protective film on the metal surface by physical and chemical adsorption.

Corrosion inhibition of stainless steel in sulfuric acid solution containing sulfide ions

Purpose Although stainless steel (SS) has good corrosion resistance in most aqueous solutions, it suffers corrosion in some solutions which contain aggressive ions such as sulfide ions. This study aims to use some cephalosporins (cefotaxime, cephapirin and cefazolin) as corrosion inhibitors of commercial SS in 0.5 M H2SO4 solution containing sulfide ions at 30°C. Design/methodology/approach The study was carried out using weight loss method, potential-time, linear polarization, potentiodynamic polarization, electrochemical impedance measurements, scanning electron microscopy, Fourier transform infrared and energy dispersive X-ray analysis. Findings The presence of the cephalosporin compound in the corrosive medium shifted the corrosion potential of SS to much positive side, which enhances self-passivation of SS, and the shifting increased with increasing inhibitor concentration. The cephalosporin compounds worked as effective inhibitors with mainly anodic and the efficiency increase as cefotaxime < cephapirin < cefazolin. The inhibitors form a protective adsorbed layer, which enriches the surface content of Ni and Cr and thus assists the SS to be passive. Originality/value The antibiotics cephalosporins could be used as effective corrosion inhibitors for SS in acidic solutions containing sulfide ions. The inhibitors enhances the the passive oxide film of SS even in presence of aggressive ions such as sulfide ions.

Natural products for material protection: corrosion inhibition of stainless steel (aisi 316l) in hydrochloric acid solution by argemone mexicana

Corrosion inhibition of stainless steel (AISI 316L) by Argemone mexicana (AM) leaf extracts has been studied in hydrochloric acid solution using weight loss, gasometric, electrochemical and surface examination techniques. Results from weight loss measurements revealed an increase in inhibition efficiency with increasing temperature and inhibitor concentration which indicates that AM leaf extracts sufficiently inhibits corrosion of stainless steel through chemisorptions of its constituent molecules. Hydrogen evolution results show that the inhibitor appreciably reduced the volume of hydrogen evolved which implies an obstruction of the cathodic reaction and reduction of corrosion rate. Data obtained from the potentiodynamic polarization scan revealed that AM leaf extracts shifted corrosion potentials of AISI 316L to more positive potential with increasing inhibitor concentration indicating a predominant anodic protection with passivation enhancing capabilities. Surface elemental analysis revealed that the formed corrosion products on the steels’ surface included heteroatom from the leaf extract which confirms that inhibition action was through adsorption of AM leaf extracts’ constituent molecules on the surface of the metal via complex chelating ligands. Adsorption of the leaf extract was seen to obey Langmuir isotherm at high temperature and obtained thermodynamic parameters were discussed.

Influence of different counterions on gemini surfactants with polyamine platform as corrosion inhibitors for stainless steel AISI 304 in 3 M HCl

The corrosion inhibition efficiency of two cationic gemini surfactants with different counterions with polyamine platform on AISI 304 stainless steel in 3 M HCl was investigated by polarisation measurements and electrochemical impedance spectroscopy (EIS). The surface of the samples was characterised before and after the corrosion experiments using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The results showed that the effectiveness of corrosion inhibiton depends on counterion belongs to surfactant molecule. The dimeric surfactant with the iodine counterion out–performs its bromine counterpart with respect to providing corrosion inhibition of stainless steel, in 3 M HCl. In the present study, the Langmuir adsorption isotherm was found to be suitable parameter for the correlating the experimental results with a possible mechanism of protection. In the case of two tested compounds the highest inhibition efficiency was found around the critical micelle concentration. Critical micelle concentration was determined using conductometric titration.

Adsorption of L-Tryptophan-derived chiral Schiff bases on stainless steel surface for the prevention of corrosion in acidic environment: Experimental, theoretical and surface studies

The effect of Schiff bases derived from L-Tryptophan, methyl 2-((2-hydroxybenzylidene)amino-3-(1H-indol-3-yl)propanoate (S1) and 2-(((1-hydroxy-3-(1H-indol-3-yl)-1,1-diphenylpropan-2-yl)imino)methyl)phenol (S2), on the corrosion inhibition of stainless steel (SS) in 1 M hydrochloric acid (HCl) solution was investigated. Electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to understand the inhibition efficiency of the inhibitors. We found that the inhibitors S1 and S2 have good inhibition efficiency on corrosion of stainless steel in 1 M HCl. Polarization measurements confirmed mixed mode of inhibition of S1 and S2 with predominant control of cathodic reaction. SEM-EDX, FT-IR, UV–visible and X-Ray Diffraction (XRD) results revealed that the inhibitor molecules were adsorbed on SS surface and their adsorption on SS obeyed Langmuir's adsorption isotherm. Density functional theory (DFT) was employed to find out quantum chemical parameters (EHOMO, ELUMO and ΔE). The obtained theoretical results have been compared with the experimental results.

Protection of chromium-nickel steel in hydrochloric acid solution by a substituted triazole

The corrosion of chromium-nickel steel 12Kh18N10T in 2.0 M HCl (t = 20–100C) was studied using mass loss, potentiometric, and polarization methods. Efficient steel protection under these conditions can be achieved by inhibitors such as triazole derivative IFKhAN-92, alone or in combination with hexamethylenetetramine in a molar component ratio of 1 : 4. The proposed mixed inhibitor often protects steel 12Kh18N10T in HCl solutions in a broad temperature range, 20–100C, more efficiently than IFKhAN-92 alone at the same concentrations. The triazole in question and its blend with urotropine ensure metal protection in acid solutions for at least 8 h. Since for IFKhAN-92 alone and its blend with urotropine the corrosion inhibition coefficients grow with an increase in temperature, at least to t = 100°C, they should be attributed to so-called “high-temperature inhibitors of acid corrosion”. The presence of inhibitors of interest in the solution considerably increases the fraction of diffusion control in the corrosion process, as indicated by the significant decrease in effective activation energy in the presence of these compounds. Steel corrosion occurs in the active dissolution region both in background and inhibited acid solutions. The corrosion potential of steel is more positive in solutions containing inhibitors because they predominantly slow down the anodic reaction. Addition of IFKhAN-92 or its mixture with urotropine to an HCl solution hinders considerably the electrode reactions on steel in the entire temperature range studied. In this case, the cathodic and anodic current densities decrease with time, while the inhibition coefficients of electrode reactions either increase or remain nearly constant. The corrosion potentials decrease with time in the presence of the additives in question at t = 20–60C, which suggests that hindrance of the cathodic reaction is predominantly improved due to adsorption of inhibitors. It has been shown that the efficient inhibition of stainless steel corrosion in HCl solution by addition of IFKhAN92 or IFKhAN-92 + urotropine results from strong hindrance of both electrode reaction on the metal by these inhibitors, which becomes stronger in time and remains in effect as the temperature increases.

Polyaniline-dodecylbenzenesulfonic acid for corrosion inhibition of stainless steel

Corrosion behavior of stainless steel was investigated by using highly processable polyanilinedodecylbenzenesulfonic acid (PANI-DBSA) salt. An Electroactivity/redox property of the polymer was investigated by cyclic voltammetry. Conducting salt form of PANI-DBSA was studied by UV-Vis spectroscopy. A solution of PANI-DBSA was drop coated on stainless steel electrode. Corrosion performances of PANI-DBSA coated and un-coated electrodes were investigated in 3% sodium chloride (NaCl) by means of DC corrosion (E Tafel) technique. The results show that PANI coating increased the corrosion resistance of stainless steel in an aggressive sodium chloride medium.

Juglans regia L. extract as green inhibitor for stainless steel and aluminium in acidic media

Corrosion inhibition of stainless steel and aluminium with the promising green eco-friendly inhibitor Juglans regia L. was tested in 1 M HCl acidic solution by using various techniques such as gravimetric (weight loss), potentiodynamic polarization and electrochemical impedance spectroscopy. An increase in inhibition efficiency was identified with the increased concentration of the inhibitor, Juglans regia extract, both in water and in ethyl acetate solutions. The inhibition efficiency was found 88.8 % in water solvent for aluminium. For each experiment, water showed better efficiency as a solvent compared to ethyl acetate. It was also realized that the inhibitor molecule had a more positive inhibiting effect on aluminium metal. In addition, the effect of immersion time (2–8 h) was discussed and the adsorption mechanism was fitted with the Langmuir isotherm. Infrared spectra were also employed to discover the changes in functional groups of the organic molecules of the extract.

Corrosion inhibition of stainless steel by a sulfate-reducing bacteria biofilm in seawater

Corrosion inhibition of stainless steel due to a sulfate-reducing bacteria (SRB) biofilm in seawater was studied. By atomic force microscopy, a layer of fish-scale-like biofilm was found to form as stainless steel coupons were exposed to the culture media with SRB, and this biofilm grew more and more compact. As a result, coupons’ surface under the biofilm turned irregular less slowly than that exposed to the sterilized culture media. Then, physicoelectric characteristics of the electrode/biofilm/solution interface were investigated by electrochemical impedance spectroscopy (EIS), and the coverage of the biofilm as well as the relative irregularity of coupons’ surface was also recorded by EIS spectra. Finally, anodic cyclic polarization results further demonstrated the protective property of the biofilm. Therefore, in estimation of SRB-implicated corrosion of stainless steel, not only the detrimental SRB metabolites but also the protective SRB biofilm as well should be taken into account.

Biocorrosion of stainless steel 316 in seawater: inhibition using an azole type derivative

Corrosion inhibition of stainless steel 316 (SS316) by 2-methylbenzimidazole (MBI) in sterile enriched artificial seawater and seawater with sulphate reducing bacteria (SRB) was investigated using direct current polarisation, electrochemical impedance spectroscopy, confocal laser scanning microscopy and atomic force microscopy. It is shown that MBI is an effective inhibitor in controlling the abiotic corrosion of SS316 and as well as biocorrosion by two strains of SRB (i.e. Desulfovibrio desulfuricans and Desulfovibrio singaporenus). The MBI effectively inhibits biocorrosion of SS316 by both D. desulfuricans and D. singaporenus, with >90% inhibition efficiency.

Effect of nitrogen ion implantation on corrosion inhibition of nickel coated 316 stainless steel and correlation with nano-structure

The influence of implantation of N+ with 20keV energy and different fluences in the range of 1×1017 and 5×1018ions/cm2 in the nickel coated type 316 stainless steel (SS) on the corrosion inhibition of SS in 3.5wt% NaCl solution is investigated. The highest available N+ fluence showed highest corrosion inhibition. X-ray diffraction (XRD) analysis showed formation of nickel nitride phases that enhanced by increasing the N+ fluence. Surface morphology was studied by atomic force microscope (AFM) and scanning electron microscope (SEM) before and after corrosion test, respectively. AFM results showed that by increasing N+ fluence surface of the sample becomes smoother that may be the result of heat accumulation during implantation causing higher rate of diffusion in the sample.

Application of Ketone-Based Resins as Anticorrosive Coating

Effect of some newly synthesized modified ketonic resins on corrosion inhibition of stainless steel (SS) and copper (Cu) was investigated in acidic medium. Carboxyl, hydroxyl, and carbonyl functionalized resins have been coated on metal electrode as a thin film by dipping method. Corrosion characteristics of coating on SS (304 L) and Cu were investigated by polarization, open-circuit, and impedance measurement. These measurements performed at different time and the stability of polymeric coating were tested with time in acidic medium. The resin coating was able to protect both the SS and copper.

Corrosion Inhibition Effect of 4-(2-Diethylamino-Ethylsulfonyl)-Phthalonitrile and 4,5-Bis(Hexylsulfonyl)-Phthalonitrile

Inhibition of stainless steel corrosion in a 3.0 M NaCl solution by 4-(2-diethylamino-ethylsulfanyl)-phthalonitrile (DAESPN) and 4,5-bis(hexylsulfonyl)-phthalonitrile (Bis-HSPN) was investigated by polarization and electrochemical impedance spectroscopy (EIS) measurements. The values of cathodic (βc) and anodic (βa) Tafel slopes, , , corrosion rate (CR), and inhibition efficiences (IE%) obtained from polarization curves and polarization resistance (), double-layer capacitance (), specific capacitance () values were obtained from EIS. Double-layer capacitance differences in the presence and absence of inhibitors were also obtained from EIS measurements as suggested in the literature in order to investigate the interaction of them with metal surface. Results show that both DAESPN and Bis-HSPN are effective in cathodic reaction. Impedance measurements suggest higher surface coverage for DAESPN. The interaction between the inhibitor and the stainless steel was investigated by the adsorption isotherm. Langmuir adsorption isotherm was applied and values were obtained and found as , and 9.2 kJ, 12.5 kJ for DAESPN and Bis-HSPN, respectively, which suggests the electrostatic interaction between charged metal surface and charged organic molecules.

Surface Analysis of Inhibitor Film Formed by Poly(Vinyl Alcohol) on Stainless Steel in Sodium Chloride Solution

The corrosion inhibition of stainless steel in 0.9% NaCl solution in presence of poly(vinyl alcohol) (PVA) is discussed according to electrochemical measurements, such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS).The morphology of the surface was analyzed using Scanning Electron Microscopy (SEM). The composition of the layer formed on stainless steel surface was estimated using X-ray Photoelectron Spectroscopy (XPS) technique. Electrochemical measurements indicated that the presence of PVA in NaCl solution decreases the corrosion current and increases the polarization resistance. The values of inhibition efficiency obtained from polarization curves and EIS measurements are in good agreement. In absence and in presence of PVA, SEM images showed that the stainless steel surface was covered with a non-uniform layer and a uniform adsorbed film, respectively. XPS analysis indicated that the surface layer consists of PVA containing a small amount of other elements, such as Na and Cl.