Steel In Sulfuric Acid Medium Research Articles

Investigation of Some Nonionic Surfactants as Corrosion Inhibitors for Carbon Steel in Sulfuric Acid Medium

Investigation of Some Nonionic Surfactants as Corrosion Inhibitors for Carbon Steel in Sulfuric Acid Medium

Effect of Immersion Time and Cooling Mode on the Electrochemical Behavior of Hot-Dip Galvanized Steel in Sulfuric Acid Medium

In this work, we investigated the influence of galvanizing immersion time and cooling modes environments on the electrochemical corrosion behavior of hot-dip galvanized steel, in 1 M sulfuric acid electrolyte at room temperature using potentiodynamic polarization technique. In addition, the evolution of thickness, structure and microstructure of zinc coatings for different immersion times and two cooling modes (air and water) is characterized, respectively, by using of Elcometer scan probe, x-ray diffraction and metallography analysis. The analysis of the behavior of steel and galvanized steel, vis-a-vis corrosion, by means of corrosion characteristic parameters as anodic (βa) and cathodic (βc) Tafel slopes, corrosion potential (Ecorr), corrosion current density (icorr), corrosion rate (CR) and polarization resistance (Rp), reveals that the galvanized steel has anticorrosion properties much better than that of steel. More the immersion time increases, more the zinc coatings thickness increases, and more these properties become better. The comparison between the two cooling modes shows that the coatings of zinc produced by hot-dip galvanization and air-cooled provides a much better protection to steel against corrosion than those cooled by quenching in water which exhibit a brittle corrosive behavior due to the presence of cracks.

The inhibitory action of Bauhinia purpurea extracts on the corrosion of carbon steel in sulfuric acid medium

The inhibitory effect of Bauhinia purpurea (Fabaceae) extract was studied in the corrosion of carbon steel in 1.0 mol∙L-1 sulfuric acid solution. This plant was collected from the Brazilian rainforest. The carbon steel protection was observed by varying the extract concentration from 50 to 500 mg∙L-1. Polarization curves revealed that this extract acted as an adsorption inhibitor decreasing both anodic and cathodic density currents. Weight loss measurements showed that the extract remains stable for at least 72 hours. The adsorption process of this extract obeyed the Langmuir adsorption isotherm. Lastly, Arrhenius plot suggested the physical adsorption of the extract.

Theoretical and experimental studies of the corrosion behavior of some thiazole derivatives toward mild steel in sulfuric acid media

<p>The corrosion behavior of iron in diluted aqueous sulfuric acid medium has been studied in the presence and absence of 6-ethoxybenzo[<em>d</em>]thiazol-2-amine (EBT), 5-bromothiazol-2-amine (BTA) and 4,5-dimethylthiazol-2-amine (DTA). Potentiodynamic measurements showed the shift of corrosion potential towards a more negative potential indicating that these compounds mostly act as cathodic inhibitors due to their adsorption on the iron surface. The adsorbed film of these molecules hinders the transport of metal ions from the metal to the solution and also retards hydrogen evolution reaction by acting as a physical barrier. The molecules were also studied by density functional theory (DFT), using the B3LYP functional in order to determine the relationship between molecular structure and the corrosion inhibition efficiencies.</p>

Investigation of Inhibition Effect and Determination of Some Quantum Chemical Parameters of an Organic Compound on the Carbon Steel in Sulfuric Acid Medium

The inhibition ability of [3-(4-methyl-pyridin-2-y1)-4-oxo-2-phenylimino-thiazolidin-5-ylidene]-acetic acid ethyl ester (MOTAE) on the corrosion behavior of carbon steel in 0.5 M sulfuric acid solution was investigated using weight loss and potentiodynamic polarization techniques. The inhibition efficiencies increased as the concentration of the compound was increased. The calculated inhibition efficiencies from the investigated methods were in good agreement. Potentiodynamic polarization measurements indicate that MOTAE acts as a mixed type inhibitor. The adsorption of inhibitor on the steel surface obeys Langmuir adsorption isotherm. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM)‎ were used to characterize the surface of the alloy. The structure of inhibitor was optimized using three quantum chemical levels. Some quantum chemical parameters as well as Mulliken charge densities for this molecule were computed and discussed.

Experimental and computational studies of Nicotiana tabacum leaves extract as green corrosion inhibitor for mild steel in acidic medium

In the present work corrosion inhibition of mild steel in 2M H2SO4 solution by Nicotiana tabacum extract was studied by weight loss method. It has been found that the extract acts as an effective corrosion inhibitor for mild steel in Sulfuric acid medium. The inhibition process is attributed to the formation of an adsorbed film of inhibitor on the metal surface which protects the metal against corrosion. The inhibition efficiency (%IE) and surface coverage (θ) of N. tabacum extract increased with increase in inhibitor concentration but decreased with increasing the temperature. The adsorption of extract on the mild steel surface was found to obey Langmuir’s adsorption isotherm. The free energy value (ΔGads) indicated that the adsorption of inhibitor molecules was typical of physisorption. The results obtained show that N. tabacum Extract could serve as an excellent eco-friendly green corrosion inhibitor. Quantum chemical parameters such as highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), energy gap (ΔE), dipole moment (μ) and Mulliken charges were calculated. Quantum chemical calculations also supported experimental data and the adsorption of inhibitor molecules onto the metal surface.

Green corrosion inhibitor for carbon steel in sulfuric acid medium from “Calotropis Gigantiea” latex

Calotropis Gigantiea latex (CGL) was used for adsorptive inhibition of corrosion of carbon steel in 0.5 M H2SO4 solution. Inhibition was studied through potentiodynamic polarization and electrochemical impedance spectroscopy. Adsorption isotherm data was recorded at different temperature settings to reveal characteristics of adsorptive inhibition and to determine energetic features of adsorption. Results indicated that CGL is a suitable green inhibitor for the corrosion of carbon steel in solutions of H2SO4 , with efficiency reaching up to 97 %. The inhibition efficiency of CGL was found to increase with increasing inhibitor concentration, but to decrease with increasing temperature. The adsorption of CGL on the carbon steel surface was found to be spontaneous and exothermic, and it was fitted with the Langmuir isotherm and found to obey the physisorption mechanism. Scanning electron microscope was employed to examine changes in the metal surface in the presence and absence of the inhibitor.

Experimental and Theoretical Investigation of 1- hydroxybenzotriazole as a Corrosion Inhibitor for Mild Steel in Sulfuric Acid Medium

Experimental and Theoretical Investigation of 1- hydroxybenzotriazole as a Corrosion Inhibitor for Mild Steel in Sulfuric Acid Medium

Covalent grafting of chitosan onto stainless steel through aryldiazonium self-adhesive layers.

Although the conventional methods for strong attachment of chitosan onto stainless steel require many steps in different solvents, it has been demonstrated in this work that covalent grafting of chitosan on a steel surface can be easily achieved through the formation of a self-adhesive surface based on aryldiazonium seed layers. Initially, a polyaminophenyl layer is grafted on a stainless steel surface by means of the one-step GraftFast(TM) process (diazonium induced anchoring process). The grafted aminophenyl groups are then converted to an aryldiazonium seed layer by simply dipping the substrate in a sodium nitrite acidic solution. That diazonium-rich grafted layer can be used as a self-adhesive surface for subsequent spontaneous coating of chitosan onto the steel surface. X-ray photoelectron and impedance electrochemical spectroscopies were used to characterize the pristine and modified steel samples. As evidenced from impedance and linear polarization results, the primary polyaminophenyl layer characterized by a high charge transfer resistance contributed to better protection against corrosion of the resulting chitosan-coated steel in sulfuric acid medium.

Corrosion Inhibition Effects of Some New Synthesized N-Aroyl-N\ -Aryl thiourea Derivatives for Carbon Steel in Sulfuric Acid Media

This research includes the synthesis of some new N-Aroyl-N -Aryl thiourea derivatives namely: N-benzoyl-N -(p-aminophenyl) thiourea (STU1), N-benzoyl-N -(thiazole) thiourea (STU2), N-acetyl-N ` -(dibenzyl) thiourea (STU3). The series substituted thiourea derivatives were prepared from reaction of acids with thionyl chloride then treating the resulted with potassium thiocyanate to affored the corresponding N-Aroyl isothiocyanates which direct reaction with primary and secondary aryl amines, The purity of the synthesized compounds were checked by measuring the melting point and Thin Layer Chromatography (TLC) and their structure, were identified by spectral methods [FTIR, 1 H-NMR and 13 C-NMR].These compounds were investigated as a corrosion inhibitor for carbon steel in 1M H2SO4 solution using weight loss, potentiostatic polarization methods; the obtained results showed that the substituted thioureas retard both cathodic and anodic reactions in acid media, by virtue of adsorption on the carbon steel surface. This adsorption obeyed Langmuir’s adsorption isotherm. The inhibition efficiency of (STU1-3) is ranging between (60-95)%. By using different (STU3) derivative concentration and temperature, the carbon steel corrosion rate was decreased with increasing (STU3) concentration and the highest inhibition efficiency reach to 98.5% by using 5×10 -4 M (STU3) concentration at 338 K, the inhibition efficiency increases with increasing temperature in the range of (308-338)K.

Investigation of the Inhibiting Effect of Cerium Ions on the Corrosion Behavior of OC404 Stainless Steel in Sulfuric Acid Medium

Investigation of the Inhibiting Effect of Cerium Ions on the Corrosion Behavior of OC404 Stainless Steel in Sulfuric Acid Medium

Experimental and theoretical investigation of organic compounds as inhibitors for mild steel corrosion in sulfuric acid medium

Three synthesized organic compounds were tested as corrosion inhibitors for mild steel in sulfuric acid medium by potentiostatic polarization, FTIR spectroscopy and SEM techniques. Quantum chemical parameters were also calculated to characterize adsorption mechanism. Acceptable correlations were obtained between inhibition efficiency and the calculated quantum chemical parameters. It was found that the investigated compounds exhibit a good inhibition effect especially at 8–10 ppm range concentration, which makes them commercially important. The adsorption of inhibitors on the surface obeys Langmuir adsorption isotherm. The values of activation energy and the thermodynamic parameters, such as K ads, Δ G ads ° , Δ H ads ° and Δ S ads ° were calculated.

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.

Thermodynamic properties of 2,5-bis(4-methoxyphenyl)-1,3,4-oxadiazole as a corrosion inhibitor for mild steel in normal sulfuric acid medium

The corrosion rates in the presence of 2,5-bis(4-methoxyphenyl)-1,3,4-oxadiazole (4-MOX) as a steel corrosion inhibitor in 0.5 M sulfuric acid, were measured by the weight loss method, in the range of temperatures from 303 to 343 K. Results obtained revealed that 4-MOX performed excellently as a corrosion inhibitor for mild steel in sulfuric acid media and its efficiency attains more than 96.19% at 8 × 10 −4 M at 333 K. The inhibition was assumed to occur via adsorption of the oxadiazole molecules on the metal surface. The Langmuir adsorption isotherm was tested for their fit to the experimental data. The apparent activation energies, enthalpies and entropies of the dissolution process and the free energies and enthalpies for the adsorption process were determined and discussed. The fundamental thermodynamic functions were used to glean important information about 4-MOX inhibitory behaviour.

The inhibition effects of benzoic acid and salicylic acid on the corrosion of steel in sulfuric acid medium

The inhibitor effect of benzoic acid and salicylic acid in sulfuric acid medium on the steel with known composition has been investigated. It has been determined that the corrosion rates decrease and that percentage inhibition efficiencies and surface coverage degrees increase with increasing acid concentration in all cases. However, benzoic acid acts as a better inhibitor compared to salicylic acid with equal concentration. It has been determined that the adsorption for both organic acids on the steel complies with the Langmuir isotherm.

Kinetic‐Thermodynamic and Adsorption Isotherms Analyses for the Inhibition of the Acid Corrosion of Steel by Cyclic and Open‐Chain Amines

The corrosion inhibition characteristics of the quadridentate macrocycle 1, 4, 8, 11 tetra‐azacyclotetradecane (cyclam) on steel in sulfuric acid media are investigated at 25, 35, 45, and 55°C, and the thermodynamic energy parameters calculated. In addition the inhibition characteristics of the open‐chain polydentate amines, ethylenediamine (en), diethylenetriamine (dien), triethylenetetraamine (trien), and tetraethylenepentamine (tetren) were investigated at 25°C. Activation‐free energies, enthalpies, and entropies for the inhibition process of both cyclam and tetren were determined from the rate constants data measured at four temperatures viz., 25, 35, 45, and 55°C at one or two fixed inhibitor concentrations. All data were compared and fitted to a previously published kinetic‐thermoydnamic model in terms of an active site occupancy parameter and a binding constant of the inhibitor to the active site. The results obtained are compared with fits obtained from the application of Fumkin and Flory‐Huggins adsorption isotherms. The first isotherm attempts to treat the deviations from the ideal Langmuir isotherm by the use of a lateral interaction parameter while the second uses a relative‐size parameter which is a measure of the relative size of the inhibitor molecule to the surface‐adsorbed water molecule. Good agreement was obtained between the kinetic‐thermodynamic and Flory‐Huggins models. The Frumkin isotherm model, however, agreed only in cases where the active site occupancy, or the relative‐size parameters were equal to or close to unity. A discussion of the strengths and weaknesses of each treatment is given. In addition, the results obtained are correlated to the chemical structure of the inhibitors, the number of donor atoms, and the macrocyclic effect.

Effect of ozonization and some additions on the corrosion and electrochemical behavior of steel 12Kh18N10T in sulfuric acid

The corrosion and electrochemical behavior of stainless steel in sulfuric acid media has been studied previously [i, 2]. The effect of ozone on the electrochemical behavior of a number of metals and steels in 2% and 70% sulfuric acid has also been studied [3, 4]. Data are given in the present communication for the effect of additions of benzimidazole (BIA) and manganese sulfate on the course of polarization curves for austenitic stainless steel 12KhI8NIOT in aerated and ozonized 20% H~SO~.