Steel In Aqueous Solution Research Articles

Corrosion behavior of mild steel in aqueous solutions of ammonium nitrate and urea

Corrosion behavior of mild steel in aqueous solutions of ammonium nitrate and urea

Tribocorrosion Behaviour of SUS430 Stainless Steel in Aqueous Solutions with Different pH

To reveal the influence of passive film on the tribocorrosion behaviour of stainless steel, SUS430 was loaded at 2.0 N or 10.0 N in aqueous solutions with various pH from 1.0 to 10.0. The pure wear behaviour was investigated in the air for comparison. The polarization behaviour, the morphology of the worn or tribocorroded surface, and the depth profiles of the formed groove were measured to discuss the mechanism. The passive state was confirmed at pH = 7.0 and 10.0, but vanished at pH = 1.0 and 2.0. The pure wear in air depended on the applied loads, rather than the sliding time. On the other hand, the tribocorrosion in deionised water was much smaller than the pure wear in air. Under a load of 2.0 N, the tribocorrosion at pH = 1.0 was weaker than pH = 2.0. However, the situation reversed when increasing the load to 10.0 N. The tribocorrosion in neutral and alkaline solutions is considerably smaller than in acid solutions.

Kinetic Analysis on Hydrogen Entry into Steel in Aqueous Solutions by Alternating Current Method

Degradation of steels due to the hydrogen embrittlement, which is related to the hydrogen penetration reaction (HPR) into steel, is a serious problem from the standpoint of infrastructure preservation. A Devanathan-Stachurski permeation technique [1, 2] is a well-known method to determine a hydrogen penetration rate in metals. In this technique, two independent electrochemical cells are arranged on right across two surfaces of thin metal sheet and anodic and cathodic polarizations can be performed with each cell using the three-electrode system. The hydrogen penetration rate can be evaluated by measuring the oxidation current of hydrogen atoms diffused in the metal sheet at the anode side. The electrochemical impedance spectroscopy (EIS) was used for electrochemical measurement with the Devanathan cell to investigate HPR mechanisms because the time constants of hydrogen evolution and entry can be discriminated [3-5]. In this study, we used a complex hydrogen penetration ratio (CHPR), which is a transfer function related to hydrogen entry and diffusion in metal sheet, with the Devanathan cell to investigate kinetics of hydrogen entry into metals. The CHPRs of carbon steel sheet immersed in aqueous solution of different pH’s were measured in this study. The rate constant of hydrogen entry was determined by comparing experimental results with the simulated ones according to the theoretical equation, and influence of pH on hydrogen entry was discussed.

Electrochemical reduction of formic acid to diamond-like carbon films on stainless steel in aqueous solutions

Diamond-like carbon (DLC) films show attractive applications in surface modification of stainless steels (SS) owing to their high corrosion resistance and low friction coefficient. Electrodeposition is a cost-efficient method to prepare carbon films. DLC films were electrodeposited from formic acid solutions, however severe hydrogen evolution on stainless steel led to extremely low current efficiencies. Sodium formate was used to reduce the concentration of protons in the electrolyte and slightly improved the current efficiency. To further inhibit hydrogen evolution, dimethyl sulfoxide was added into the electrolyte as a proton acceptor. The current efficiency for carbon deposition increased more than 28 times, and the deposition rate reached as high as 1.6 μm h−1. The corrosion and wear resistance of DLC coated stainless steel were improved.

Chemical facets of environment-friendly corrosion impediment of low-carbon steel in aqueous solutions of inorganic mineral acid

Chemical facets of environment-friendly corrosion impediment of low-carbon steel in aqueous solutions of inorganic mineral acid

Cathodic Corrosion Inhibition of Steel by Musa Paradisiaca Leave Extract

It is reported here that the phytochemicals present on the surface of the Musa paradisiaca (MPL) prevent water and other corroding agents from having direct access to the surface of mild steel. These phytochemicals were extracted from the MPL using 70% Ethanol solution and Weight Loss experiment was carried out with variation of temperature, time and concentration HCl and that of the MPL extract in % v/v. The inhibition eFFect of M. paradisiaca leaves of mild steel in aqueous solutions of Hydrochloric acid were investigated at 25, 35, 45 and 60 oC being immersed simultaneously and independently in the acid medium over a period of 12, 24, 48, and 72 hours. A protecting film appeared on the metal surface by the MPL extract via electron donation, hence, acting as the cathode. The temperature and immersion time were inversely proportional to inhibition effciency while concentration of MPL is directly proportional. FT-IR of the extract showed oxygen and nitrogen containing functional groups which are the general characteristics of a typical corrosion inhibitor, while the Gas Chromatography–Mass Spectrometry (GC–MS) investigation revealed different biomolecules thus suggesting that the plant extract consists of different molecules.

Corrosion inhibition behavior of the synthesized pyrazoline-sulfonamide hybrid of mild steel in aqueous solutions: experimental and quantum investigations

Corrosion inhibition behavior of the synthesized pyrazoline-sulfonamide hybrid of mild steel in aqueous solutions: experimental and quantum investigations

Synthesis and Characterization of Polypyrrole Film Doped with Both Molybdate and Salicylate and Its Application in the Corrosion Protection for Low Carbon Steel.

Polypyrrole (PPy) films doped with molybdate and salicylate have been successfully electropolymerized on low carbon steel in aqueous solutions containing both molybdate and salicylate in a one-step process that did not require any pre-treatment of the steel substrate. Salicylate-doped PPy films were synthesized in the same way for comparison. The steel surface was rapidly inhibited and the PPy-based films were formed on it easily. The PPy-based films were characterized by Fourier transform infrared, scanning electron microscopy, energy dispersive X-ray, and thermal gravimetric analysis methods. The corrosion protection performance of the coatings was investigated with electrochemical impedance spectroscopy, open circuit potential (OCP), salt spray test, and Tafel polarization. It was found that in the presence of both molybdate and salicylate as dopants, the films on steel could present a better corrosion resistance than PPy film doped with only salicylate. The self-healing property of PPy-based films was observed on the OCP measurement with the fluctuation of rest potential. The salt spray test results showed that the PPy film doped with both salicylate and molybdate was more salt-resistant than the PPy film doped with only salicylate. The results suggest that the PPy coatings doped with both molybdate and salicylate are potential for application as metallic anti-corrosion coatings.

Understanding the synergistic effect of CO2, H2S and fluid flow towards carbon steel corrosion

The synergistic effect of CO2, H2S and fluid flow towards carbon steel pipelines was studied by systematically evaluating the corrosion response of AISI 1020 carbon steel in aqueous solutions containing CO2 and CO2/H2S at various contents under the static and dynamic conditions at 60 °C. The results have revealed that the dissolved H2S can impede the formation of FeCO3 crystals by the preferential adsorption process of FeHSads+ to form the porous iron sulfide scale, through which the corrosive species, especially in dissolved CO2, can easily reach the steel/scale interface and accelerate the dissolution of steel matrix. On the other hand, the limited adsorption process of FeHSads+, enhanced mass transport of corrosive species/Fe2+ along with easy spalling of iron sulfide scale with poor adhesion are expected under the action of fluid flow, ultimately aggravating the localized and general corrosion of carbon steel.

Experimental and computational chemical studies on the corrosion inhibitive properties of carbonitrile compounds for carbon steel in aqueous solutions

The present work aims to study 6-amino-4-aryl-2-oxo-1-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile derivatives namely: 6-Amino-2-oxo-1,4-diphenyl-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-H), 6-Amino-2-oxo-1-phenyl-4-(p-tolyl)-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-Me) and 6-Amino-4-(4-hydroxyphenyl)-2-oxo-1-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-OH) as corrosion inhibitors to provide protection for carbon steel in a molar hydrochloric acid medium. Chemical measurements such as (weight loss) and electrochemical techniques such as (Potentiodynamic polarization, electrochemical impedance spectroscopy, and Electron frequency modulation) were applied to characterize the inhibitory properties of the synthesized derivatives. The adsorption of these derivatives on the carbon steel surface was confirmed by Attenuated Total Refraction Infrared (ATR-IR), Atomic Force Microscope (AFM), and X-ray Photoelectron Spectroscopy (XPS). Our findings revealed that the tested derivatives have corrosion inhibition power, which increased significantly from 75.7 to 91.67% on the addition of KI (PdC-OH:KI = 1:1) to inhibited test solution with PdC-OH derivative at 25 °C. The adsorption process on the metal surface follows the Langmuir adsorption model. XPS analysis showed that the inhibitor layer consists of an iron oxide/hydroxide mixture in which the inhibitor molecules are incorporated. Computational chemical theories such as DFT calculations and Mont Carlo simulation have been performed to correlate the molecular properties of the investigated inhibitors with experimental efficiency. The theoretical speculation by Dmol3 corroborates with the results from the experimental findings.

Mesoscopic transformation at initial corrosion stage of 20# steel in aqueous solution under gas–liquid two-phase stratified flow condition

PurposeThis study aims to investigate the initial corrosion behavior in aqueous solution of 20# seamless steel under (CO2/aqueous solution) gas–liquid two-phase stratified flow conditions.Design/methodology/approachThe initial corrosion behavior was studied through the weight loss methods, scanning electron microscopy with energy-dispersive x-ray spectroscopy and x-ray diffraction.FindingsThe corrosion rate of 20# steel obviously increases with the increasing gas pressure at different corrosion time when the CO2 pressure is less than 0.11 MPa, and the increase of corrosion rate tends to be steady when the pressure exceeds 0.11 MPa. With the increase of CO2 pressure, the corrosion products changed from flocculent to acicular, granular and scaly. A four-stage model for the growth of the corrosion product layer was proposed, namely, the diffusion reaction stage, the local film formation stage, the complete film formation stage and the densification stage of the product film.Originality/valueA four-stage model for the growth of the corrosion product layer on the pipe wall surface under this condition was proposed, namely, the diffusion reaction stage, the local film formation stage, the complete film formation stage and the densification stage of the product film. The growing process and densification mechanism of corrosion products layer were discussed.

Effect of salinity on the corrosive wear behaviour of engineering steels in aqueous solutions

The effect of salinity is assessed on the corrosive wear behaviour of a low-alloy steel (UNS G43400) and three stainless steels (UNS S15500, UNS S31600 and UNS S32760). Erosion-corrosion testing was conducted using a submerged impingement slurry jet test-rig. Three salinities were evaluated; 0.05%NaCl, 3.5%NaCl and 10%NaCl. Total volume losses (TVL) and a volumetric analysis technique were used to assess the damage in the directly-impinged zone (DIZ) and outer area (OA). Under all measured parameters, material loss for the stainless steels increased marginally with increased salinity. In terms of TVL and OA volume loss, the low alloy steel exhibited significantly greater material loss from 0.05%NaCl to 3.5%NaCl conditions, however, no further increase was evident when the salinity was raised to 10%NaCl.

Synthesis and Characterization of new Ethoxylated Carbohydrate based Surfactants for Corrosion Inhibition of low LCS Steel in Aqueous Solutions

The heterocyclic compounds, mainly carbohydrate-based surfactant, 1, 4 Sorbitan, namely (Sorbitan Mono-stearate with 20 moles of Ethylene oxide SMS-20-EO, Sorbitan Mono-oleate SMO, and Sorbitan Mono-oleate ethoxylated with 20 moles of Ethylene oxide SMO-20-EO ) have been synthesized and characterized through different spectroscopic methods (FTIR, 1H NMR). Then estimated as corrosion inhibitors of low LCS (LCS) in the aggressive environment 1 M HCl utilizing a weight loss (WL), the destructive and destructive electrochemical techniques. The surface examination was tested using several techniques. The new ethoxylated carbohydrate-based surfactant gave an excellent inhibition performance (IE %). The adsorption of the inhibitors obeys the Langmuir adsorption model. The metal dissolution and inhibitor adsorption phenomena have been studied via the estimation of thermodynamic parameters, which describe the adsorption properties of SMO, SMO-20-EO, and SMS-20-EO.

Computational Study of Corrosion in Steel in Aqueous Solution: a Review

Corrosion affects most of the material strength and causes damages to the material and the structure. Corrosion has become a major problem of material stability and it is difficult to predict its phenomenon. It can happen in any environment and can deteriorate metallic material. Computational models have been implemented in order to study and predict the phenomenon and the evolution of the corrosion. This paper presents a critical review of the computational model from various softwares that have been developed to observe the growth and the behaviour of corrosion on the metallic material in aqueous solution. The metallic material undergoes redox reaction with the presence of oxygen and water to form corrosion. This paper reviews the corrosion model of steel at different pH, temperatures and types of ionic species. The pH of the aqueous solution is either acidic or alkaline which will determine the rate of corrosion by the ionic reaction in the electrolyte.

Comparative study of corrosion resistance between four non-commercial high manganese steel models and 9% nickel steel in aqueous solution of H2SO4

Abstract The present study aims to establish a comparison of corrosion resistance between four (non-commercial) high manganese steel models in relation to 9% nickel steel in an aqueous solution of H2SO4. High manganese steels have emerged as an alternative material for the manufacture of equipment for the storage and transportation of liquefied petroleum gas due to their mechanical properties and mainly for the lower cost compared to 9% nickel steel. The electrochemical techniques used were open circuit potential, linear polarization and electrochemical impedance spectroscopy. The results obtained by these techniques have helped to understand the phenomena that produce a lower corrosion resistance of high manganese steels when compared to 9% nickel steel in aqueous solutions.

Investigation of microstructure and corrosion behavior of weathering steel in aqueous solution containing different anions for simulating service environments

The microstructure and corrosion behavior of weathering steel in three solutions (S1: 3.5 wt.% NaCl, S2: 3.5 wt.% NaCl+0.052 wt.% NaHSO3, S3: 3.5 wt.% NaCl+0.907 wt.% NaHCO3) were investigated. A high proportion of random boundaries is responsible for strong corrosion sensitivity. The thickness of rust increases with immersion time and is in the order of S1＞S3＞S2. The rust formed in S1 and S2 solutions mainly consists of γ-FeOOH phase, but the latter is less protective. The rust formed in S1 solution is dense and thick resulting in its protection being similar to that in S3 solution.

A Comparative Study of Green Inhibitors for Galvanized Steel in Aqueous Solutions

This study investigates the morphology, composition and corrosion resistance of hot dip galvanized (HDG) steel bolts in fresh water, 1% NaCl saltwater in the presence of protective compounds L-Tryptophan and three conventional corrosion inhibitors: Inhibitor 1-VCI (amine-carboxylates-based), Inhibitor 2 (based on carboxylate acid), and Inhibitor 3 (water-based, carboxylate acid). Quantitative tests performed include gravimetric analysis and electrochemical techniques, such as linear polarization, Tafel extrapolation, and Electrochemical Impedance Spectroscopy (EIS). Electrochemical measurements determined the polarization resistance Rp, corrosion rate vcorr, and corrosion potential Ecorr. Furthermore, Scanning Electron Microscopy (SEM) and ATR-FTIR spectrometry were used to evaluate and characterize the formed layers on the surface of hot-dip galvanized steel samples. The results reveal that upon corrosion new compounds are formed onto the exposed areas of the treated bolts such as zinc-carbonates, zinc-hydroxides, etc. The presence of these compounds on the surface of the HDG steel bolts hinders the corrosion process by reducing the rate of the anodic and cathodic reactions. The gravimetric test showed that L-tryptophan in distilled water has mass increase, resulting from the formation of white deposits on the sample surface. In fresh water and distilled water, the best corrosion resistance was achieved with Inhibitor 1-VCI, while L-tryptophan showed best results in 1% NaCl solution.

Corrosion characteristics of carbon steel in solutions of synthetic detergents

Data of corrosion rate are obtained experimentally, values of braking coefficient, protection degree of steel 10 in 3 % aqueous solutions of detergents ML-52, MS-8 and Labomid-203 are calculated. It is found that when the composition of synthetic detergents diethylene tetraborate ammonium (DETA) composition (NH4)2B4O7·2C2H8N2·2H2O concentration of 0.5 % wt., the corrosion rate of carbon steel is significantly reduced, and the values of the braking coefficient and the protection degree increase and reach almost significant values. By removing the potentiodynamic polarization curves, it is shown that in the presence of DETA, the dissolution potentials of steel 10 are shifted to the positive side relative to the potential in the background solutions and the anode process is predominantly slowed down. Corrosion-fatigue tests indicate increase in the coefficient of cyclic strength reserve of carbon steel in aqueous solutions of synthetic detergents with the addition of DETA. The results allow us to recommend the compound diethylene tetraborate ammonium as effective anticorrosive additive to synthetic detergents used to clean parts from technological contaminants in the repair of process metallurgical plants machines.

Corrosion Failure of AISI4340 Steel in Oxygen-Containing Aqueous Chloride Solution

Stress corrosion cracking behavior of 4340 steel in oxygen-containing or chloride containing aqueous solution was researched, the tensile experiment results indicated 100°C deaerated distilled water, the rupture of 4340 steel mainly belongs to ductile fracture, the addition of oxygen or chloride would increase the SCC tendency of 4340 steel and transformed the rupture mechanism from ductile fracture to brittle rupture, the existence of oxygen or chloride would decreaseKISCCof 4340 steel in 100°C aqueous solution slightly, the simultaneous action of oxygen and chloride existed, and the simultaneous action would further increase the SCC tendency of 4340 steel in aqueous solution.

Opto-electrochemical Instruments; Detection of Crevise Corrosion

Background: Two techniques of laser optical interferometry have been reviewed for detection of crevice corrosion of low carbon steel samples in aqueous solutions. The first technique used an optical corrosion-meter to detect localized corrosion such as crevice corrosion, of the low carbon steel samples in seawater. The concept of the optical corrosion-meter was based on incorporating holographic interferometry and the cyclic polarization test. The second technique used a modified electrochemical noise technique based on holographic interferometry to detect crevice corrosion of the low carbon steel samples in 1 M of sodium hydroxide (NaOH) solution. Objective: Emphasis on the significant role of the optical techniques of detecting crevice corrosion of carbon steel in aqueous solutions alongside to the DC methods. Method: The optical corrosion-meter and the modified electrochemical noise technique were used in the present investigation. Results: Observations of crevice corrosion of the carbon steel samples in seawater by the optical corrosion-meter were found to be in agreement with the cyclic polarization test. In addition, the modified electrochemical noise technique was found to be very useful for quantitatively distinguishing of localized corrosion, passivation, and uniform corrosion of the carbon steel samples in 1 M NaOH solution. Conclusions: The optical techniques of detecting crevice corrosion of carbon steel in aqueous solutions were found efficient opto-electrochemical instruments for substantiating results of those DC methods. Keywords: Electronic instruments, electrochemical properties, electromagnetic field, optical corrosion-meter, holographic interferometry, electrochemical noise technique, and opto-electrochemistry.