Steel In Sulfuric Acid Research Articles

Allium sativum as Corrosion Inhibitor for Carbon Steel in Sulfuric Acid

Allium sativum as Corrosion Inhibitor for Carbon Steel in Sulfuric Acid

Salvia Hispanica as Eco-Friendly Inhibitor for Mild Steel in Sulfuric Acid

Salvia hispánica seeds extract has been investigated as a carbon Steel corrosion inhibitor in 0.5 M sulfuric acid by using polarization curves, electrochemical impedance spectroscopy, electrochemical noise and weight-loss, tests at different concentrations (0, 100, 200, 400, 600, 800 and 1000 ppm) and temperatures, namely 25, 40 and 60 °C. Results show that inhibition efficiency increases as the inhibitor concentration increases, decreases with temperature. The extract inhibit corrosion mainly by an adsorption mechanism. Potentiodynamic polarization studies show that extract is mixed-type inhibitors.

Effect of W, Mo, and Ti on the Corrosion Behavior of Low-Alloy Steel in Sulfuric Acid

The effects of W (0.05 wt% W), Mo (0.05 wt% Mo), and Ti (0.05 wt% Ti) addition on the corrosion resistance of low-alloy steel used in flue gas desulfurization systems were examined using electrochemical measurements in a 10 wt% sulfuric acid (H2SO4) solution. The corrosion rate increased in the following order: W steel < Mo steel << Ti steel. The surface analysis indicated that the type and quantity of inclusions by steel are as follows: W steel (manganese sulfide [MnS]) < Mo steel (MnS, molybdenum disulfide [MoS2]) << Ti steel (MoS2, titanium sulfide [TiS]). The corrosion rate was influenced by sulfide inclusions in the steels. In particular, the corrosion rate of Ti-containing steel was the highest due to a large number of TiS inclusions formed during the steel manufacturing or corrosion processes.

On the Origin of the Second Anodic Peak During the Polarization of Stainless Steel in Sulfuric Acid

The origins of the second anodic current peak in polarization curves of AISI 430 (UNS S43000) stainless steel in deaerated 0.1 M sulfuric acid (H2SO4) have been investigated by potentiodynamic polarization and atomic emission spectroelectrochemistry (AESEC). The elemental dissolution rates of Fe, Cr, Ni, Cu, and Mn were measured in real time during linear potential sweep voltammetry, revealing the formation and dissolution of a copper-rich corrosion product layer. The deposition and subsequent dissolution of this copper layer is proposed to be the main cause of the second anodic current peak. The negative current loop observed after the first anodic peak is attributed to the cathodic reduction of H+ ion on the copper-enriched layer. Other factors such as the oxidation of the adsorbed H atoms on the copper-enriched layer and the presence of chromium-impoverished grain boundaries are shown to have a negligible effect on the second anodic current peak.

Effect of molybdenum and tungsten polyoxometalates on the composition of surface layers and electrochemical behavior of stainless steel in sulfuric acid

The composition and thickness of the surface layers formed on ferrite steel at various applied potentials in pure 1 N H2SO4 and in the presence of polyoxometalate (POM) anions ( in cationic composition are observed near the passivation potential. At anodic potentials the surface oxide layer is enriched by chromium oxide. The thickness of this layer does not exceed 2-3 nm. If polymolybdate or polytungstate anions are added to sulfuric acid, they are located mostly in the uppermost oxide layer. The anodic currents decrease notably with an increase in POM concentration. At the passivation potential the oxide layer thickness exceeds 3-4 nm and it is substantially enriched by molybdenum. On the samples kept for 1 h in 1 N H2SO4, a protective layer is formed in the presence of POM and an after-affect is achieved. This layer remains stable upon transfer into pure 1 N H2SO4, especially in the case of

Inhibition of acid corrosion of mild steel by Anacyclus pyrethrum L. extracts

Inhibition of the corrosion of mild steel in sulfuric acid by extracts of Anacyclus pyrethrum L. (leaves and stems, AP-LS; flowers AP-F; roots, AP-R) has been studied by use of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. Anacyclus pyrethrum L. inhibited the corrosion of mild steel in 0.5 M H2SO4 solution. Polarization curves show that the different parts of plants act as anodic type inhibitors. Changes in impedance data (charge transfer resistance, Rt, and double layer capacitance, Cdl) were indicative of adsorption of the extracts on the metal surface, leading to the formation of protective films. The extent of surface coverage by the inhibitors was determined by measurement of ac impedance; it was found that adsorption of these inhibitors on the mild steel surface obeys the Langmuir adsorption isotherm. Activation energies in the presence and absence of AP-LS and AP-F were obtained by measuring the temperature dependence of the corrosion current.

Effect of chromium on the corrosion behavior of low alloy steel in sulfuric acid

The effects of a chromium (Cr) addition on the corrosion resistance of low alloy steel used in flue gas desulfurization systems were examined by electrochemical (potentiodynamic polarization tests, linear polarization measurements and electrochemical impedance spectroscopy) and weight loss measurements in a 10 wt% H2SO4 solution at room temperature. All measurements revealed a decrease in corrosion rate with increasing Cr content. SEM, EPMA and XPS examinations of the corroded surfaces after the immersion test indicated that 0.6% Cr addition decreased corrosion damage to the steels because protective Cr oxides formed in all the rust layers and Fe oxides dominated over Fe sulphate compounds in the inner rust layers.

Corrosion Protection Properties of 4-[(E)-[(2,4-Dihydroxy phenyl)methylidene] amino]-6-methyl-3-sulfanylidene-2,3,4,5-tetrahydro-1,2,4-triazin-5-one [DMSTT] Toward Mild Steel in Sulfuric Acid

The inhibition of mild steel corrosion in aerated 0.5 N H2SO4 solution was investigated using potentiodynamic polarization studies (Tafel), linear polarization studies, electrochemical impedance spectroscopy studies, adsorption studies, and surface morphological studies. The effect of inhibitor concentration on corrosion rate, the effect of temperature, degree of surface coverage, adsorption kinetics, and surface morphology are investigated. The inhibition efficiency increased markedly with increase in the additive concentration and decreased slightly with increasing temperature. The presence of DMSTT decrease the double-layer capacitance and increase the charge transfer resistance. The value of activation energy (Ea) of metal corrosion, adsorption equilibrium constant (Kads), and free energy of adsorption (ΔGads) were calculated from the temperature dependence of corrosion current. The adsorption of inhibitor molecule on mild steel surface follow Langmuir isotherm. DMSTT offers excellent inhibition properties and acts as a mixed-type inhibitor.

Techniques for In Situ Corrosion Studies of 316L Stainless Steel in Sulfuric Acid Solutions

An in situ optical microscopy and simultaneous electrochemical analysis method is presented for studying 316L stainless steel in sulfuric acid based solutions. The electrochemical methods involved potentiostatic and potentiodynamic analysis of 316L stainless steel surface in aerated and deaerated 1M-3.39M H2SO4 while varying Ni+ and Cl-. This technique is reviewed along with several other in situ surface analytical probes and patents such as scanning tunneling microscopy (STM), scanning electrochemical microscopy (SECM) and variations on SECM (near fieldalternating current) and the results are discussed in conjunction with various theories and applications. The results when compared to SECM data indicate that the SECM resolution, control and performance are improved. The results also illustrate the wide variety of corrosion behaviors possible for 316L stainless steel under potentiostatic and potentiodynamic test conditions. Analysis of these samples provides both a detailed visual account of the corrosion process in addition to standard electrochemical analysis regarding pitting potentials, corrosion potential and corrosion rate. Polarization data and analysis regarding the corrosion patterns observed is presented including in situ images of etching, surface layer changes and pitting. Images and analysis of chromium carbide and sulfide inclusion behaviors in sulfuric acid were performed showing the tendency of inclusions to dissolve and act as nucleation sites for pits. Keywords: Aerated, dearated, etching, grain boundaries, inclusions, in situ, optical, pitting, potentiostatic, potentiodynamic, polarization, SEM-EDS, 316L, 1M-3.39M H2SO4

Corrosion Inhibition of Carbon Steel in Sulfuric Acid by [BMIm] [Lys] Amino Acid Ionic Liquids

The corrosion inhibition effect and mechanism of the amino acid ionic liquids—1-butyl-3-methylimidazolium Lysine ([BMIm][Lys]) for carbon steel in 5% H2SO4solution are investigated by electrochemical tests. The results indicate that the [BMIm][Lys] has a good inhibition performance for the carbon steel in 5% H2SO4solution. The corrosion inhibition efficiency improves with the increase of the concentration, which arrives at 95% ultimately. The study also shows that the inhibitors are mixed-type ones. The adsorption of the inhibitor molecules on the carbon steel surface obeys Langmuir adsorption isotherm.

Effect of Copper Addition on the Active Corrosion Behavior of Hyper Duplex Stainless Steels in Sulfuric Acid

The effect of copper (Cu) addition on the active corrosion behavior of hyper duplex stainless steels in sulfuric acid was investigated. The addition of Cu in the base alloy enhanced the resistance to general corrosion by decreasing the critical and corrosion current densities, and increasing the polarization resistance. There are two primary reasons for the considerable enhancement of the corrosion resistance of the experimental alloys containing Cu. First, the protective surface film was enriched with the noble metallic copper (Cu) due to the selective dissolution of the active metallic Cr, Fe, and Ni, and the electrochemical dissolution of the corrosion products such as iron-sulfide (FeS2), iron sulfate (FeSO4), ferrous oxide (FeO) and hydrous iron sulfate (FeSO4·7H2O). Second, chromium oxide (Cr2O3), chromium trioxide (CrO3), nickel oxide (NiO), molybdenum dioxide (MoO2), molybdenum trioxide (MoO3), and tungsten trioxide (WO3) in an oxide state, molybdenum oxy-hydroxide (MoO[OH]2) and chromium hydroxide (Cr[OH]3) in a hydro-oxide state, molybdate (MoO4 2¹ ) and tungstate (WO4 2¹ )a s corrosion inhibitors in an ion state, and ammonium (NH4 + ) elevating the pH in an ion state were increased and assisted in improving the corrosion resistance. [doi:10.2320/matertrans.M2012008]

Electrochemical Measurements of Corrosion Inhibition of Mild Steel in Sulfuric Acid by BIMGCS12-3

Gemini benzimidazole cationic surfactant, propanediyl-α, ω-bis-(N-dodecyl benzimidazole ammonium bromide), referred as BIMGCS12-3, was synthesized from the raw materials of benzimidazole, dodecane bromide and dibromopropane. The structure of the target compound was confirmed by HNMR and elemental analysis. Electrochemical behaviors of BIMGCS12-3 for protecting mild steel from sulfuric acid corrosion were issued. Changes in impedance parameters (charge transfer resistance, Rct, and double layer capacitance, Cdl) were indicative of the feasibility of BIMGCS12-3 as excellent mild steel corrosion inhibitor in sulfuric acid.

Effect of Phosphorus on the Corrosion Behavior of Carbon Steel in Sulfuric Acid

Abstract This study examined the influence of phosphorus addition on the corrosion resistance of carbon steel for a flue gas desulfurization (FGD) system using electrochemical methods, such as pote...

Tribocorrosion of stainless steel in sulfuric acid: Identification of corrosion–wear components and effect of contact area

Electrochemical and friction measurements during unidirectional sliding tests are used to monitor and to evaluate the tribocorrosion behavior of a passivating material. Tribocorrosion is the interplay between chemical, electrochemical, and mechanical processes leading to a degradation of materials immersed in a corrosive environment. The tribocorrosion of AISI 316 stainless steel immersed in a diluted sulfuric acid solution at 25 °C was investigated. A modification of the surface characteristics and material loss result from the combined periodic mechanical removal of the surface film during sliding, and the subsequent (electro)chemical re-growth of that surface film in-between two successive sliding contact events. This phenomenon is addressed in this paper as a latency time effect, and its influence on the wear volume and the coefficient of friction is reported. Furthermore, the effect of galvanic coupling between areas without and covered with surface films, on the open-circuit potential is analyzed in terms of Hertzian contact area. Finally a new approach of the concept of synergism in tribocorrosion is presented and validated for AISI 316 immersed in 0.5 M H 2SO 4 under sliding against zirconia.

Inhibition action of tween‐80 on the corrosion of cold rolled steel in sulfuric acid

AbstractThe inhibition action of a nonionic surfactant of tween‐80 on the corrosion of cold rolled steel (CRS) in sulfuric acid (H2SO4) has been investigated by weight loss and potentiodynamic polarization methods. Atomic force microscope (AFM) provided the CRS surface conditions. The results show that tween‐80 is a good inhibitor in 1.0 M H2SO4, and its adsorption obeys Langmuir adsorption isotherm. Effects of temperature (20–50 °C) and acid concentration (0.5–7.0 M) on the inhibition action were investigated. Polarization curves show that tween‐80 is a mixed‐type inhibitor in sulfuric acid, but prominently inhibits the cathodic reaction. The results obtained from weight loss and potentiodynamic polarization are consistent, and the inhibition action could also be evidenced by AFM images.

Raphia hookeri gum as a potential eco-friendly inhibitor for mild steel in sulfuric acid

Exudate gum from Raphia hookeri (RH) was tested as corrosion inhibitor for mild steel in H2SO4 using weight loss and hydrogen evolution techniques at 30–60 °C. Results obtained revealed that RH act as corrosion inhibitor for mild steel in sulfuric acid medium. The corrosion rates in all concentrations studied increased with rise in temperature. The inhibition efficiency was observed to increase with increase in RH concentration but decreased with rise in temperature, which is suggestive of physical adsorption mechanism. The inhibitive action of RH is discussed in view of the adsorption of its phytochemical components onto steel surface, which protects the metal surface and thus do not permit the corrosion process to take place. The adsorption of the exudate gum onto the steel surface was found to follow the Langmuir adsorption isotherm. The free energies for the adsorption process and the apparent activation energies, enthalpies and entropies of the dissolution process were determined. The fundamental thermodynamic functions were used to glean important information about the RH inhibitory behavior. The results were explained in terms of chemical thermodynamics.

Application of the Modified Electrochemical Potentiokinetic Reactivation Test to Study Passivity and Corrosion of Metals in Aqueous Solutions

Abstract To apply the electrochemical potentiokinetic reactivation (EPR) test to study corrosion phenomena other than sensitization and intergranular corrosion in Fe-Cr-Ni alloys, the mechanism of the EPR test is discussed, and examples of its broad applicability are given. More complete insight into the active-passive transition process is provided by the EPR test compared to traditional anodic polarization measurements. A modified EPR test was used to study passivity and corrosion of 1018 steel, chromium, nickel, and AISI 321 (UNS S32100) stainless steels in sulfuric acid (H2SO4) and nitric acid (HNO3) solutions. The test results show that electrochemical information measured in the breakdown of anodic passivity of a metal-aqueous solution system is important in understanding the nature of passivity and corrosion. The test results show that the anodic reactivation is a common phenomenon, and chemical activators like potassium thiocyanate (KSCN) are often not required; thus, a modified EPR test can provi...

Apparent Inversion of the Effect of Alloyed Molybdenum for Corrosion of Ordinary and Enhanced 316L Stainless Steel in Sulfuric Acid

AbstractAn aging assessment of the OPG waste resin storage system predicted the potential for premature failure of the carbon steel resin liners. Consequently, resin liners made of 316L stainless steel with a minimum content of 2.5% molybdenum were selected to replace the carbon steel liners. The 2.5% Mo 316L stainless steel was specified to enhance pitting resistance in the spent resin environment. With the additional Mo, one would expect that a brief electrochemical corrosion test will reveal the superiority of such alloy over conventional 316L steel. This study reports a contrary experience

Studies on preparing and corrosion inhibition behaviour of quaternized polyethyleneimine for low carbon steel in sulfuric acid

Quaternized polyethyleneimine (QPEI) was prepared via two procedures of macromolecular reactions, tertiary amination reaction and quaterisation, and its chemical structure was characterized with infrared and UV spectra. In this paper, the corrosion inhibition property of QPEI for low carbon steel (A 3 steel) in H 2SO 4 solution was mainly investigated by using weight loss method, electrochemical technique (potentiodynamic polarization curves) and scanning electron microscopy (SEM) investigation. Meanwhile, the corrosion inhibition mechanism of QPEI was also fully explored. The experiment results show that as a polymeric quaternary ammonium salt, QPEI is quite an excellent corrosive inhibitor, it possesses outstanding inhibition action for low carbon steel, and only with 5 mg L −1 of QPEI concentration, the inhibition efficiency of A 3 steel can reach to 92% in 0.5 M H 2SO 4 solution for 72 h of immersing time. The inhibition efficiency increases with the increase of QPEI concentration, and the inhibition efficiency also increases with the enhancement of the cationic degree (quaternized agree) of QPEI. QPEI acted as a mixed type inhibitor with anodic predominance. QPEI possesses functions of double filming, adsorption filming and polymer filming, so with the cooperation of the two filming effects, QPEI can form a compact barrier film on A 3 steel surface, and prevent metal dissolution and retard H + discharging. The adsorption of QPEI on A 3 steel surface was found to follow the Langmuir isotherm equation.

Interpretation of EIS data on passive steel surfaces in aqueous sulfuric acid solution in terms of carrier migration and recombination

A model is proposed for the description of the interplay of charge carrier migration, effected by external voltage and combination within very thin passive oxide layers. This theory is used to describe the electrochemical impedance spectra of passive stainless steel in sulfuric acid, a prototype of such surfaces. A simple R s − Z mr | | R p circuit is considered with Z mr accounting for dispersion and R p for the Faraday process. Z mr is based on a continuous time random walk (CTRW) expression and it is seen to be independent of voltage. R p shows a strong voltage dependence which can be understood in the negative voltage range as a Butler-Volmer-Erdey-Grúz process, whereas in the positive range it can be described in terms of tunneling across the oxide. Curve fitting results in parameters characteristic to oxide structure and process kinetics. All fitted quantities are seen to be realistic with the exception of charge carrier density which turned out to be much too high, indicating that mobility might not obey the classical, frequency-independent law.