Steel In Chloride Media Research Articles

Dissolution and redistribution behavior of Cu-rich phase: Implications for corrosion resistance in Cu-bearing duplex stainless steel in chloride media

In this study, the dissolution and redistribution behaviors of the Cu-rich phases were investigated to determine their effect on the corrosion resistance of Cu-bearing 2205 duplex stainless steels. This investigation revealed the presence of Cu-rich phases with varying precipitation modes in ferrite and austenite, as well as a decrease in corrosion resistance as their size increased. The Cu-rich precipitate was preferentially dissolved compared to the steel matrix. A corrosion-product layer was formed on the surface of the alloy. The Volta potential difference between the Cu-bearing corrosion products and the matrix was lower than that between the Cu-rich phase and the matrix. This reduction in the potential difference enhanced the corrosion/passive film stability and improved the corrosion resistance of the alloy.

Comparative Study of Cetyl Trimethyl Ammonium Bromide, Formaldehyde, and Isobutanol Against Corrosion and Microbial Corrosion of Mild Steel in Chloride Media

Comparative Study of Cetyl Trimethyl Ammonium Bromide, Formaldehyde, and Isobutanol Against Corrosion and Microbial Corrosion of Mild Steel in Chloride Media

Inhibitive Characteristics of Cefalexin Drug Addition on Corrosion Evolution of Mild Steel in Chloride Medium

The inhibition effect of Cefalexin on the corrosion of mild steel in sodium chloride has been examined with the use of weight loss and potentiodynamic polarization methods at ambient temperature. Cefalexin showed good protection ability by adsorbing on the mild steel surface. The mixed inhibition characteristics of Cefalexin were revealed by the Potentiodynamic polarization results. The inhibitor efficiency was found to be above 65% obeying the Langmuir and Freundlich isotherm law with correlation regression coefficients of R2 = 0.9984 and R2 = 0.9488, respectively. The closeness of these R2 values to unity established the reliability of Cefalexin as an inhibitor.

Electrochemical and Mechanical Investigation of Newly Synthesized NiO-ZrO2 Nanoparticle–Grafted Polyurethane Nanocomposite Coating on Mild Steel in Chloride Media

NiO-ZrO2 nanoparticles were prepared and characterized by Fourier transformed infrared spectroscopy (FTIR) and x-ray diffractometer (XRD) analysis. The NiO-ZrO2 nanoparticles were incorporated into polyurethane (PU) and the resultant polyurethane (PU)/NiO-ZrO2 nanocomposite was coated on the steel sample. The anticorrosion behavior of the PU/NiO-ZrO2 nanocomposite coating was electrochemically studied and compared with pure polyurethane coating by scanning electrochemical microscopy (SECM), potentiodynamic polarization studies and electrochemical impedance spectroscopy (EIS). EIS studies showed a pronounced protection performance for PU/NiO-ZrO2 coating in natural seawater. SECM analysis measured lower current for the PU/NiO-ZrO2 at the scratch of the coated surface compared to PU coating. The surface characterization and elemental composition of the coated samples were examined by surface morphological studies (SEM/EDX). Dynamic mechanical analysis (DMA) test was also carried out to examine the coated nanocomposite. The results provided valuable information about the protective performance and failure analysis of PU/NIO-ZrO2 nanocomposite coated surface. Field emission-scanning electron microscopy/energy-dispersive x-ray (FE-SEM/EDX) analysis was used to examine the corrosion products formed on the surface of coated sample. The formation of thin films of oxides and chlorides of Ni and Zr blocks the penetration of corrosive ion in the coating/metal interface. It was revealed from the mechanical properties of the nanocomposite and pure PU coatings that mixed metal oxide nanoparticles (NiO-ZrO2) enhanced mechanical as well as protection properties of the polyurethane coating against corrosion. A possible protection mechanism is also proposed.

Ethanol extract of waste potato peels for corrosion inhibition of low carbon steel in chloride medium

Abstract Corrosion of low carbon steels is a big constraint in their smooth use for engineering applications. Corrosion not only destroys their designed properties but also harms their physical appearance. Several researchers are working to minimize the effect of corrosion on low carbon steel. In this regard, they have consumed a lot of synthetic and natural materials till date. Nowadays, researchers are showing their trust on natural materials for corrosion inhibition application due to their easy availability, negligible toxicity and easy synthesis process as well as eco-friendly nature. It is an established fact that waste natural materials (WNMs) like banana peels have very high potential for being used in corrosion inhibition application due to their bioactive contents. However, WNMs have not been explored frequently by the researches despite their supreme technical and economical importance in corrosion inhibition. In this work, ethanol extract of waste potato peels is used for corrosion inhibition of low carbon steel in 0.5 M NaCl. The inhibition properties of the extract are determined by weight loss measurements, open circuit potential (OCP) curves, electrochemical impedance spectroscopy (EIS), Tafel polarization curves and linear polarization resistance (LPR) techniques. Results show that maximum corrosion inhibition efficiency of 70% has been achieved using 1000 mg L−1 of the extract. Scanning electron microscopy (SEM) and energy dispersive X-RD Spectroscopy (EDX) has also shown that the extract has successfully protected low carbon steel in 0.5 NaCl.

5-(4-methoxyphenyl)-3h-1, 2-dithiole-3-thione as an Effective Inhibitor for Corrosion of Bridge Steel in Chloride media

5-(4-methoxyphenyl)-3h-1, 2-dithiole-3-thione as an Effective Inhibitor for Corrosion of Bridge Steel in Chloride media

Surface morphological and quantum chemical studies of some expired drug molecules as potential corrosion inhibitors for mild steel in chloride medium

Three anti-diabetic drug based biomolecules (Acarbose, Voglibose and Miglitol) were investigated for their corrosion inhibitive effect on mild steel in 700 ppm NaCl solution. Corrosion tests were conducted using weight loss measurements, electrochemical measurements, surface morphologies, quantum chemical studies and molecular dynamics simulation techniques. The results showed increasing corrosion inhibition efficiency with increasing concentrations of all studied biomolecules. The addition of Zn ion (synergistic effect) increased the inhibition of Acarbose, Voglibose and Miglitol on mild steel to a considerable extent. The anodic mode of inhibition mechanism was proposed for the effect of examined inhibitors, as revealed by Tafel polarization technique. Adsorption process of all the investigated inhibitors on the mild steel surface obeys the Langmuir adsorption isotherm. The surface morphologies of the mild steel were studied using SEM and EDXA. The experimental results are well correlate with the quantum chemical and molecular dynamics simulation results. The trend of corrosion protection efficiency of the drug based biomolecule is Ac > Vo > Mi as observed from experimental, theoretical and simulation studies.

Oxidation of AISI 304 Steel in Al- and Ti-Containing Solutions

The present work was devoted to a study of the effect of the electrolyte composition on the anodic behavior of stainless steel. Morphology and X-ray phase composition of oxide coatings formed in Al- and Ti-containing electrolytes have been investigated. Electrical conductivity and defects of the coatings have been studied by the method of impedance spectroscopy. It has been established that the introduction of aluminum or titanium oxides into the coating composition reduces the corrosion rate of steel in chloride media.

Effect of TiN addition on corrosion behavior of spark plasma sintered 304L austenitic stainless steel in chloride media

The corrosion hazards emanating from industries where the use of stainless steel is inevitable has led to the development of materials which are capable of withstanding corrosive environments. In addition to specimen sectioned from a hot rolled austenitic stainless-steel plate, the effect of different weight percentages (2, 4 and 6%) of titanium nitride (TiN) reinforcement addition on the corrosion property of sintered austenitic stainless steel were investigated in 3.5 wt% NaCl electrolyte. Chronopotentiometry and potentiodynamic polarization techniques were used in analysing the corrosion resistance of specimens in the electrolyte. Optical micrographs from a high-resolution microscope showed the formation of more pits on the substrate surfaces of hot rolled and unreinforced sintered specimens, while fewer or no pits were observed on specimens with TiN addition. The corrosion potentials and current densities of specimens obtained from chronoamperometry and potentiodynamic polarization plots further confirmed an improvement in the corrosion resistance of specimens with 2 and 4 wt% TiN reinforcement.

Corrosion Inhibition of Martensitic Stainless Steel in Chloride Medium by Calcium Gluconate-Solanum Tuberosum Extract as Surfactant

Corrosion inhibition of martensitic stainless steel (MSS) in magnesium chloride was investigated in the absence and presence of calcium gluconate as corrosion inhibitor at ambient temperature. The effects of inhibitor concentration were studied using weight loss and polarization method. The results obtained showed that calcium gluconate acts as an inhibitor for martensitic stainless steel in MgCl and decreases the corrosion rate. The inhibition performance was found to increase with the increase in inhibitor concentration. The maximum inhibition efficiency obtained was 99 % at 2g/v inhibitor concentration, the adsorption of calcium gluconate on the surface of Martensitic stainless steel was found to obey Langmuir adsorption isotherm. However, the addition of solanum tuberosum extract in the inhibitor decreases the corrosion rate of martesitic steel significantly in chloride solution.

Inhibitory Effect of Ethanolic Extract of Propolis on Corrosion of Ferritic Stainless Steel in Chloride Media

This work evaluates the inhibitory effect of ethanolic extract of propolis (EEP) on the corrosion of AISI 409 stainless steel (SS) in chloride media. Additions of 100, 200, and 500 μL of EEP in an aqueous sodium chloride solution were performed. The inhibitory effect on the SS was evaluated using electrochemical impedance spectroscopy (EIS) measurements up to 720 hours in immersion. EEP additions of 200 μL and 500 μL increased the polarization resistance of the SS. After 720 hours of immersion, the highest impedance was identified for the SS in solution with 500 μL of EEP. The maximum inhibition efficiency observed for addition of 500 μL of EEP in solution was 98.1 %, after 360 h of immersion.

Corrosion protection of steel cut‐edges by hot‐dip galvanized Al(Zn,Mg) coatings in 1 wt% NaCl: Part I. Experimental study

Corrosion of AlZnMg coated steel in chloride media is a complicated process, which progress is determined not only by the electrode reactions but also by the local pH and formation of soluble and insoluble corrosion products. In order to adequately describe and predict the corrosion behavior of steel/AlZnMg cut‐edge, a multi‐ion transport, and reaction model (MITReM) is built. Such model takes into account the transport of species in the solution together with their production/consumption in electrochemical and chemical reactions. The main aim of this work is the validation of a numerical model for describing and predicting corrosion of steel/AlZnMg cut‐edge in immersed conditions. This first part describes the experimental work done to obtain model input parameters and validation measurements. The metallic coatings are characterized experimentally with respect to their composition and microstructure, global and local electrochemical behavior (polarization curves, AESEC, and SVET). Local distribution of corrosion products and local pH are also characterized. No blocking effect of the precipitated corrosion products has been observed and dedicated measurements are performed to validate this observation. Based on the experimental input from this part, numerical models of cut‐edge corrosion with different levels of details are developed in Part II.

Corrosion behavior and surface analysis of 690 MPa-grade offshore steels in chloride media

High-strength low-alloy steels have been used prevalently in marine engineering and the defense industry because of their superior yield strength, toughness, and weldability. Although these materials have excellent mechanical properties, the corrosion resistance of high-strength low-alloy steels is a crucial problem, particularly when they are used in a marine environment. In this study, the corrosion behavior of a newly designed NiCu-containing low-carbon steel (NiCu steel) and conventional S690Q alloy steel (S690Q steel) was investigated and compared. Potentiodynamic polarization results indicated that for NiCu steel, current densities are apparently reduced in the anodic region. Surface analyses indicated that NiCu steel created a thick and uniform inner rust layer after it was immersed in NaCl solution for 7 days. Furthermore, a high-density Cr-rich region was observed in the NiCu inner rust layer after an immersion test. Electrochemical impedance spectroscopy results suggested that NiCu steel exhibits higher corrosion resistance than S690Q steel in NaCl solution.

Electrochemical and Surface Studies of Thiourea-formaldehyde as corrosion Inhibitor for N80 Steel in Chloride Media

Electrochemical and Surface Studies of Thiourea-formaldehyde as corrosion Inhibitor for N80 Steel in Chloride Media

Properties and performance of spin-on-glass coatings for the corrosion protection of stainless steels in chloride media

Spin-on-glass deposition was investigated as viable alternative to increase the durability and performance of 316L steel in chloride environment. The buildup of a detrimental interface oxide was prevented by non-oxidative thermal curing of the coatings, which leads to a transformation to an inorganic, SiO2-like material. The degree of polymerization was found dependent on the curing temperature; however, even curing at the maximum investigated curing temperature of 800 °C led to still incomplete transformation, showing less SiO2-like character with respect to thermally grown oxide or fused silica. Electrochemical analysis by cyclic polarization indicated that the coatings behave as imperfect barrier coatings, which may enhance the passive properties of the substrates; however, there is still some statistical scatter in the quality of the coatings. While there is a tendency for an increase of the upper limit of the breakdown potential, there is also a decrease of the lower limit. It was found that such lower quality coatings showed, in association with substrate defects, unevenly distributed coating flaws, which may act as initiation points of pitting corrosion and decrease the corrosion resistance of coated substrates. Further, the films showed instability in aqueous environment due to imperfect polymerization.

Corrosion of bare and silane-coated mild steel in chloride medium with and without sulphate reducing bacteria

Abstract Influence of Bis[triethoxysilyl]ethane (BTSE) silane coating on the corrosion resistance of a mild steel in an aerobic chloride medium and an anaerobic microbial medium containing sulphate reducing bacteria (SRB) was analysed using a comprehensive electrochemical and chemical analyses. The Silane coating acted as a physical barrier and significantly improved the corrosion resistance of mild steel in an aerobic chloride medium. However, the improvement was limited in the anaerobic microbial medium. Surface morphology examination and chemical analysis using Fourier transformed infrared spectroscopy confirm the formation of a dense biofilm on BTSE-coated surface after pre-exposure to biotic media, which can be attributed to the absence of any antimicrobial functional group in this silane. This study is first of its kind to indicate the limitations of established coating systems in retarding microbial corrosion and emphasizes the importance of the modification of current coating systems with anti-microbial functional groups to impede the formation of biofilms and effectively hinder microbial corrosion.

The Effect of Cations on Carbon Steel Corrosion in Chloride Media

The corrosion of carbon steel in chloride media has been investigated extensively in literature [1, 2]. However, the role of cations in carbon steel corrosion behavior is not widely reported. In the present work, the effect of Na+, K+ and NH4 +cations on the corrosion of carbon steel in chloride media is investigated via. potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and field emission scanning electron microscopy (FESEM) measurements. All the electrochemical measurements were carried out using a three electrode system, and after open circuit potential reaches a stable value. The carbon steel was used as working electrode. The reference and counter electrode were Ag/AgCl (3M KCl) and platinum wire respectively. The concentration of chloride is 10 wt.% for all the solutions. The polarization curves were obtained by scanning the electrode potential from -250 mV to 500 mV w.r.t OCP at a scan rate of 1 mV/s. The impedance spectra were obtained by applying an AC perturbation signal of 10 mV in the frequency range 100 kHz to 10 mHz. The polarization measurements (Fig. 1) reveals that the corrosion rate is higher in case of ammonium chloride (NH4Cl) solution following the order NH4 +> K+ > Na+. Further, the polarization measurements, in case of chloride solutions containing Na+ and K+ cation shows the formation of passive layer on the carbon steel surface (the regime of insignificant current increase with potential) followed by breakdown of the same (the regime of increase in current) indicating susceptibility to pitting corrosion. While the anodic polarization curve in the presence of NH4 +cation does not show any sign of passivation. This implies that the carbon steel is more prone to uniform corrosion. These results suggest the formation of passive layer on the carbon steel surface and the mechanistic reaction pathway of carbon steel dissolution in chloride media is strongly influenced by the cations present in the solution. The EIS measurements performed at open circuit potential, shows two time constant for all the cations (Fig.2). However, for NaCl and KCl system, the two time constants are merged and appears to be a single capacitive loop. The impedance data is analysed by an appropriate electrical equivalent circuit (EEC) and the EEC parameters are retrieved. Impedance results also confirms that the corrosion rate is higher in NH4Cl solution while lower in NaCl solution. So the presence of cations affect both the corrosion rate and the corrosion mechanism. Keywords: Carbon steel, cations, chloride media, polarization, EIS

Corrosion inhibition and surface analysis of amines on mild steel in chloride medium

In this study, the corrosion inhibition effectiveness of eight amines, i.e. 2-ethylhexyl amine, aniline, benzylamine, butylamine, ethylamine, isopropylamine, octylamine, and triethanolamine, on C15 grade mild steel in 3 wt% NaCl solution is reported. The corrosion inhibition performance of the amines was studied using immersion tests at 25 and 70 °C, with and without the addition of KI as a possible intensifier. Among the inhibitors tested at 0.1 wt% concentration, the lowest corrosion rates were obtained for specimens immersed in solutions containing 2-ethylhexyl amine at 25 °C and triethanolamine at 70 °C. The highest inhibition effectiveness at 25 °C among all amines tested was obtained for 1.0 wt% butylamine with the addition of 0.5 wt% KI, while at 70 °C the lowest corrosion rate was obtained for specimens inhibited with 1.0 wt% isopropylamine. Surface analysis was subsequently performed on specimens inhibited by the most effective inhibitors. Adsorption of the selected amines on the C15 grade mild steel surface was confirmed by ATR-FTIR. 3D-profilometry showed a reduction in the surface roughness (less corroded) for the specimens inhibited with these inhibitors compared to the non-inhibited specimens. Contact angle measurements showed that all of the tested specimens were hydrophilic.

Impact of hybrid self-assembled nanophase particle-based sol–gel coatings on the localized corrosion behavior of modified 9Cr–1Mo steel in chloride medium

Corrosion protection coatings were developed based on a hybrid self-assembled nanophase particle process (HSNAP) for the localized corrosion resistance of modified 9Cr–1Mo steel in 0.05 M NaCl solution. The coating sol was prepared using silane-zirconia precursors and a polymeric crosslinking agent. Scanning electron microscopy and X-ray photoelectron spectroscopy were used to study the morphology and composition of the coated specimens, respectively. The thickness of the coatings was determined by a thickness gauge meter and Raman imaging analysis. The corrosion resistance of coated specimens was analyzed using electrochemical impedance spectroscopy, and it was observed that HSNAP-coated specimens showed superior resistance to localized corrosion than the as-received specimens in chloride medium.

The corrosion inhibition of certain azoles on steel in chloride media: Electrochemistry and surface analysis

This study analyses the corrosion inhibition efficiency of certain azoles for C15 grade mild steel in 3wt.% NaCl solution by employing immersion tests and different electrochemical techniques. The possible synergistic effect of azole inhibitors and metal salts was also investigated. It was found that tolyltriazole is the most effective corrosion inhibitor. Additional surface analyses were performed for specimens inhibited with tolyltriazole. ATR-FTIR analysis confirmed the adsorption of tolyltriazole on the steel surface and 3D⿿profilometry and AFM showed that tolyltriazole reduces surface roughness compared with non⿿inhibited solution. Contact angle analysis showed that tolyltriazole-inhibited steel specimens evidenced a hydrophilic character.