Corrosion Behavior Of Carbon Steel Research Articles

Experiments and Molecular Simulations to Study the Effect of Surface-Active Compounds in Mixtures of Model Oils on CO2 Corrosion during Intermittent Oil-Water Wetting.

Intermittent oil-water wetting can have a significant effect on the internal corrosion of steel pipelines. This paper presents a combined experimental and molecular modeling study of several influential factors on the surface properties and corrosion behavior of mild steel in CO2 environments. The influence of different model oils (LVT-200 and Aromatic-200) and select surface-active compounds (myristic acid, cyclohexane butyric acid, and oleic acid) on the corrosion behavior of carbon steel during intermittent oil-water wetting was determined by measuring the corrosion rate after intermittent wetting cycles. The interfacial tension measurements were performed to study the incorporation of the oil phase along with surface-active molecules in the protective layer formed on the specimen surface. Results showed that the interfacial tension for an aromatic oil-water interface is lower than that for an aliphatic oil-water interface. To understand this result, molecular dynamics simulations of oil-water interfaces were performed in the presence of surface-active molecules and different oils to analyze the structure of the layer formed at the interface. The simulations supported the hypothesis that aromatic molecules are less structured at the interface, which results in the incorporation of more water molecules into the protective layer formed at the steel surface, causing a higher corrosion rate. On the other hand, the simulations revealed that myristic acid in an aliphatic oil forms a well-aligned structure at the interface, devoid of any water molecules. This is in agreement with the hypothesis that the linear molecular structure of myristic acid favors the alignment of molecules at an aliphatic oil-water interface, resulting in a lower interfacial tension and more effective corrosion mitigation as compared to the other two nonlinear compounds tested. It is concluded that an important factor controlling the corrosion behavior is the molecular structure of the oil-water interface, which is adopted by the steel surface layer through the Langmuir-Blodgett process.

Suitability of using simulated porous‐like solutions to evaluate the steel corrosion in carbonated concrete

AbstractThe use of simulated solutions is a common practice in corrosion studies to assess easily and quickly the corrosion behaviour of materials in real situations. In this context, it is frequent to substitute tests performed in concrete or mortar with tests performed in porous‐like solutions. Particularly, to simulate carbonated concrete, different carbonated porous‐like solutions (CPS) are found in the literature. However, it is not known whether the use of these solutions accurately predicts the behaviour of steel bars embedded in carbonated concrete. In the present work, a comparison between the corrosion behaviour of carbon steel in carbonated mortar and in different CPS was performed. It was found that none of the CPS studied in the present work adequately simulate the corrosion behaviour of the steel in carbonated mortar, but the CPS containing high concentrations of carbonates/bicarbonates is the only one that provides corrosion rates close to those obtained in carbonated concrete.

Corrosion Behavior of Carbon Steel in LiCl/H2O Mixtures

The corrosion behavior of 1018 carbon steel in LiCl/H2O mixtures has been evaluated by using potentiodynamic polarization curves, electrochemical noise and electrochemical impedance spectroscopy techniques. Two different concentrations of LiCl were employed, namely 35 and 40 wt. %, and the testing temperatures included 25, 35 and 70 °C. It was found that the steel showed a passive zone; the corrosion current density value increased with an increase in the solution temperature and concentration. The pitting potential value decreased with an increase in the testing temperature and the solution concentration. The corrosion process was under charge transfer control. This mechanism was unaltered either by the solution temperature or concentration. The charge transfer resistance value decreased with an increase in both the solution temperature and concentration. A localized, pitting type of corrosion dominated the corrosion morphology at 25 and 35 °C, whereas at 70 °C, the main type of attack was a mixed type of corrosion.

Effect of SO42− in aerobic/anaerobic environment and its interaction with HCO3− on corrosion behavior of carbon steel

Effect of SO42− in aerobic/anaerobic environment and its interaction with HCO3− on corrosion behavior of carbon steel

Corrosion Behavior of Carbon Steel in Diethylenetriamine Solution for Post-combustion CO2 Capture.

In the realm of postcombustion carbon capture, diethylenetriamine (DETA), recognized for its substantial CO2 absorption capacity, presents a formidable challenge due to its corrosive impact on equipment. This study delves into the corrosion behavior of 20# carbon steel immersed in DETA solutions under varying conditions, employing weight loss and electrochemical methods. The investigation incorporates scanning electron microscopy/energy-dispersive spectroscopy and X-ray diffraction analyses for characterization. Corrosion experiments were also conducted in monoethanolamine (MEA) solutions for a comparative analysis. Results from the corrosion tests in DETA solutions mirror the temperature-dependent corrosion rate (CR) observed in MEA. However, a distinctive trend emerges as the CO2 loading of DETA increases from 0.2 mol CO2/mol amine to 1.2 mol CO2/mol amine, leading to a continuous decrease in the CR of carbon steel-contrary to MEA solutions. This anomaly is attributed to DETA's robust complexing ability with metal ions and its elevated solubility of Fe2+ in solution. Additionally, an examination of the corrosion mechanism in the presence of oxygen was conducted through characterizing the specimen surface and solution precipitates postexperiment. The absence of a protective FeCO3 layer can be attributed to insufficient concentrations of free Fe2+ and CO32- in the solution, failing to achieve the minimum saturation required for protective film formation. The insights gained from studying the corrosion behavior of carbon steel in DETA solutions lay the groundwork for subsequent developments in corrosion inhibitors.

Corrosion Investigation of Carbon Steel in Different Amine-Based CO2 Removal System

The steel industry is a major source of CO2 emissions, which is affecting the corrosion behavior of carbon steel. The corrosion behavior of carbon steel (C1018) absorbed for CO2 removal is examined in different blends of amine solution by adding a heat-stable salt neutralizer and increasing amine concentration. Corrosion of carbon steel using different methyldiethanolamine (MDEA)/ (5% piperazine amine solution) which had 26% amine solution that contained heat stable amine salts treated with neutralizer at 80 °C and CO2 loading was investigated. The effect of the treated solutions on the corrosion behavior was observed using either the K2CO3 treatment solution to reach 30% amine or increasing the concentration to 33% amine solution using weight loss, potentiodynamic polarization, cyclic voltammetry, and impedance measurements. A visual examination of the corroded samples of the different amine solutions was performed. XRD for phase identification and SEM for microstructure examination were used to describe the corroded surfaces and analyze the corrosion products on the specimen surfaces under different conditions. After nine days in the 30% amine solution, these analyses showed the formation of the FeCO3 protective layer. The carbon steel in 30% amine solution provides better protection, and the lowest corrosion resistance (39.9 µm/Y).

The influence of chlorides on corrosion behavior of carbon steel in slag-based geopolymer pore solution

The electrochemical behavior and surface characteristics of carbon steel are investigated to clarify the influence of Cl− on its corrosion resistance in simulated slag-based geopolymer pore (SSGP) solution in this study. Adsorption layer (about 40–60 nm) forms in Cl−-containing SSGP solution, thus maintaining the passivity of the reinforcement in SSGP solution with 3.5 wt % and 7 wt % Cl−. The passive film contains FeO/FeS internal film and FeOOH/Fe2O3 external film, exhibiting slightly reduced passive film resistance in Cl−-containing SSGP solution. Further, the critical Cl− content in SSGP solution is dramatically larger than that in simulated cement pore solution, which is associated with the existence of adsorption layer and subsequently competitive adsorption of silicates.

Effect of formic acid (HCOOH) on the corrosion protectiveness of magnetite (Fe3O4) at elevated temperature

The corrosion behavior of carbon steel in an aqueous solution containing dissolved CO2, H2S, and HCOOH at high temperature was investigated by conducting a series of systematic experiments. The influence of each (possible) corrosive species (CO2, H2S, and HCOOH) on corrosion mechanisms were explored through detailed analysis of corrosion rates and corrosion product layers. The results showed that the formation and integrity of the Fe3O4 layer was compromised in the presence of HCOOH, probably due to the formation of Fe(COOH)+which impedes the formation of Fe3O4 at the initial stage of the corrosion process.

Analysis of Beibu Gulf tidal zone exposure on properties of carbon steel

Marine tidal zone is a corrosive environment that has a negative impact on carbon steel. This research investigates the change of mechanical properties and corrosion behaviour of carbon steel specimens subjected to field exposure test and simulation test for 12 and 6 months, respectively. The corrosion behaviour of carbon steel exposed to real marine tidal zone and simulation environment was discussed through morphological observation and corrosion kinetics analysis, in order to reveal the essential reason for the degradation of its mechanical properties. Then the tensile test was performed on the corroded specimens and true stress–strain curves were obtained. In addition, regression equations were derived for the mechanical properties as a function of the degree of corrosion degradation and a constitutive model with time factor for corroded carbon steel is proposed.

Comparative evaluation of corrosion behaviour of carbon steel (C1020) in different biodiesels: Synthesis, characterization and electrochemical investigations

The environmental concerns and government regulations have led to a surge in preparation of biodiesels as one of the main components for renewable and alternative fuels from cost effective biowastes. The degradation of biodiesel during storage produces organic acids that could lead to the corrosion of component parts of the engine thus it is imperative to define the rate of corrosivity of this golden alternative before its application. The current study utilizes electrochemical methods (OCP, EIS and PDP) in addition to advanced techniques such as SEM, UV–vis and FTIR to investigate the comparative corrosion behaviour of three biodiesels namely; jatropha oil biodiesel (JOB), neem oil biodiesel (NOB) and waste cooking oil biodiesel (WCOB) on carbon steel. The surface morphology of the post corrosion steel samples as characterized by SEM revealed differences in surface damage due to corrosion in the various systems. The study further inferred that the investigated biodiesel requires specific carbon steel component type for compatibility and effectiveness in fuel delivery and storage systems of automobile engines which were evident by the different corrosion degradation rates (103, 74 and 51 mpy) for JOB, NOB and WCOB respectively. The overall results showed differential corrosion rates of the order JOB > NOB > WCOB on carbon steel under similar experimental conditions.

A comparative study on the corrosion behavior of Q235 steel in saturated acidic red and yellow soils

Purpose The purpose of this paper is to study the corrosion behavior of Q235 steel in saturated acidic red and yellow soils. Design/methodology/approach The corrosion behavior of Q235 steel in saturated red and yellow soils was compared by weight-loss, SEM/EDS, 3D ultra-depth microscopy and electrochemical measurements. Findings Rp of the steel gradually increases and icorr gradually decreases in both the red and yellow soils with time. The Rp of the steel in the red soil is lower, but its icorr is higher than that in the yellow soil. The uniform corrosion rate, diameter and density of the corrosion pit on the steel surface in the red soil are greater than those in the yellow soil. Lower pH, higher contents of corrosive anions and high-valence Fe oxides in the red soil are responsible for its higher corrosion rates and local corrosion susceptibility. Originality/value This paper investigates the difference in corrosion behavior of carbon steel in saturated acidic red and yellow soils, which can help to understand the mechanism of soil corrosion.

Electrochemical investigation of the “double-edged” effect of low-dose biocide and exogenous electron shuttle on microbial corrosion behavior of carbon steel and copper in enriched seawater

The microbiologically influenced corrosion (MIC) behavior of carbon steel and copper induced by SRB was investigated by low levels of the biocide tetrakis hydroxymethyl phosphonium sulphate (THPS) and the environmental electron shuttle riboflavin in early incubation and harsh conditions. After 7 days of incubation, riboflavin weakened the inhibition for SRB by THPS in the carbon steel system, but did not apply to the copper. Thirty ppm THPS inhibited planktonic cell proliferation, but still formed visual biofilms on carbon steel and copper surfaces. In the co-existence of THPS and riboflavin, higher corrosion rates were obtained in carbon steel, while the MIC of copper was mitigated. For the harsh biotic systems, thirty ppm THPS was ineffective against the SRB-MIC of the harsh systems. Riboflavin was the icing on the cake for carbon steel under this condition, accelerating the SRB-MIC process. Electrochemical noise currents were used to monitor the effects of chemical injection in harsh conditions.

Corrosion behavior and mechanism of carbon steel in industrial circulating cooling water system operated by electrochemical descaling technology

Electrochemical descaling technology (EDT) can significantly increase the concentration ratio of industrial circulating cooling water systems (CCWSs), thereby reducing water, capital, and energy consumption. However, our understanding of the impact of EDT on carbon steel corrosion in CCWSs is limited, which increases the risk of long-term operation. In this study, the influence of the EDT on the corrosion characteristics of carbon steel was comprehensively investigated in field CCWSs (E-CCWSs) and compared with a system using traditional chemical processes (C-CCWSs). The corrosion characteristics, corrosion products, and corrosion mechanism of carbon steel have been studied using various testing methods, including the weight loss method, electrochemical testing, Confocal Laser Scanning Microscopy (CLSM), Advanced Mineral Identification and Characterization System (AMICS), etc. The research showed that the corrosion behavior of carbon steel in a circulating water system was similar and could be divided into three stages: the initial stage (corrosion rate increased), middle stage (corrosion rate slowed down gradually), and later stage (corrosion rate was stable). Owing to the lack of the corrosion inhibitor film, the corrosion rate of carbon steel in the electrochemical circulating water system was faster in the initial stage. However, the rapidly thickened corrosion product layer had a protective effect on the carbon steel. The corrosion of carbon steel entered the middle and late stages faster, and the corrosion rate decreased rapidly and tended to stabilize. In the long term, the corrosion rate of carbon steel in the electrochemical system was slightly lower than that in the chemical system. E-CCWS encounter serious pitting problems. At 120 days, the pitting depth in electrochemical systems was 108.22 μm, almost twice as deep as that in chemicals (54.79 μm). This research has important reference value for corrosion prevention and risk assessment of EDT for practical applications.

Waterline corrosion behaviors of carbon steel covered by organic coating with artificial defects in seawater

The waterline corrosion behaviors of carbon steel covered by organic coating with artificial defects at and under the waterline simultaneously in simulated artificial seawater were studied by the wire beam electrode (WBE) and electrochemical impedance spectroscopy (EIS) technologies. It was first proposed that the corrosion process of the metal substrate covered by organic coating under the waterline was mainly divided into three stages: no significant corrosion reactions of the metal substrate occurred; the cathodic reaction occurred with relatively slight corrosion on the metal substrate; cathodic delamination of the coating occurred, and the metal substrate was further corroded. Due to the different concentrations of dissolved oxygen, the corrosion reactions of the two exposed electrodes at the waterline and under the waterline were dominated by cathodic and anodic reactions, respectively. For the electrodes under the waterline, on account of the anodic dissolution reaction of the metal substrate, the cathode to anode polarity reversal occurred. In addition, for the yellow corrosion products, the main components were α − Fe2O3, β − FeOOH and γ − FeOOH, while α − Fe2O3 and Fe3O4 were the main components of the black corrosion products. γ − FeOOH participated in the cathodic reaction to form Fe3O4, which resulted in the reduction of the anodic current density at the electrode surface.

Effect of free radicals generated by UV and semiconductor corrosion products on the inhibition behaviour of Ce3+

The effect of free radicals generated by photocatalysis on the inhibition behaviour of Ce3+ was investigated. Inhibition behaviour of Ce3+ was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy and the concentration of Ce3+ is detected by inductively coupled plasma-optical emission spectroscopy. Results confirmed that free radicals have no evident effect on the corrosion behaviour of carbon steel or zinc, but the corrosion inhibition efficiency of Ce3+ gradually decreases with the extension of ultraviolet (UV) irradiation time and increasing UV light intensity. Studies showed that the free radicals generated under photocatalysis gradually convert Ce3+ into Ce4+, which quickly form precipitation in the medium, thereby reducing the corrosion inhibition performance of Ce3+.

A new perspective on the corrosion of carbon steels in H2SO4 acid environments: Statistical analysis of corrosion mechanisms by response surface modeling

This study investigated synergistic effect of temperature, solution velocity, and sulphuric acid concentration on corrosion behaviour of carbon steel using response surface methodology. Electrochemical and surface characterisation techniques were employed. A statistically significant mathematical model was obtained, correlating corrosion rate to the environmental parameters. Temperature affected anodic reactions, while solution velocity influenced cathodic reactions. Acid concentration profoundly influenced corrosion mechanisms by altering deposition, dissolution, and properties of FeSO4 surface layer. The lowest corrosion rate was 0.546 mm/year at 35 °C, 98.5 wt%, 0 rpm, and the highest was 368.223 mm/year under 70 °C, 49 wt% and 500 rpm.

Corrosion behavior of carbon steel covered with a coating film containing metallic compounds under a sulfuric acid mist environment containing chloride

AbstractThe corrosion behavior of carbon steel covered with coating films containing Al2(SO4)3, CaO, and BaO was examined under a sulfuric acid mist environment containing chloride. CaSO4･2H2O and BaSO4 were formed as the corrosion products in the coating film and prevented the penetration of corrosives, in particular BaSO4 was highly effective. Furthermore, the rust layer containing CaCO3 adhered to the carbon steel substrate suppressed the penetration of chloride. The formation of these corrosion products suppressed the anodic reaction, resulting in higher corrosion resistance of the carbon steel in the chloride‐containing acid environment.

Interaction between silty sand and temperature towards corrosion behavior of carbon steel in CO2 environment

The interaction between silty sand and temperature towards corrosion of carbon steel in CO2 environment is investigated. The effect of silty sand is more complicated, while the effect of temperature is more remarkable. High temperature causes a more protective corrosion products layer. Silty sand physically adsorbs on the surface and embeds in the porous Fe3C layer at 40 ℃ to slightly reduce corrosion. At 80 ℃, silty sand delays FeCO3 precipitation and significantly increases the porosity of corrosion products layer, thus promoting corrosion. At 120 ℃, silty sand increases the porosity and hinders the formation of Fe3O4 to accelerate corrosion.

Effects of Different Fouling Organisms on Corrosion Behavior of Carbon Steel in Dalian Seawater

Carbon steels are widely used in ocean engineering due to their cost effectiveness, ease of manufacture, and excellent weldability. However, the attachment of macro-fouling organisms in seawater poses a serious threat to the integrity of carbon steel structures. In this experiment, carbon steel plates were immersed in the Dalian Sea area from January to October to investigate the effects of macro-fouling on corrosion propagation. The electrochemical measurement indicated that the propensity for the corrosion of Q235B is ranked as ascidians > mussels > barnacles. The characterization results indicated that various marine organisms significantly influenced the corrosion behavior of Q235B carbon steel immersed in natural seawater. The colonization of barnacles inhibited corrosion at the barnacle central area, and the presence of barnacle covering caused crevice corrosion at the edges of the barnacle due to oxygen concentration cells. The presence of ascidians resulted in general corrosion due to the locally high conductivity and ion diffusion rate. A relatively compact rust layer, which exhibited localized defects, was observed beneath the mussels. Seawater had the ability to penetrate the rust layer through these defects, leading to the formation of pitting corrosion on the metal substrate.

Understanding the intrinsic effect of fly ash on passivity and chloride-induced corrosion of carbon steel and stainless steel in cement extract solutions

Compared with the ordinary Portland cement extract solution (OPC solution), the passivation capability and chloride-induced corrosion behavior of carbon steel (Q235) and 316 stainless steel (316ss) in fly ash modified cement extract solution (FA solution) were intensively investigated in this study. The composition and electrochemical properties of steel passive films were studied using XPS technique and a series of electrochemical measurements including M − S, EIS and CPP. Moreover, FT-IR, AFM and SEM/EDS were employed to analyze the corrosion products and morphology on the steel surface. After 10 d of passivation, the film resistance of Q235 in OPC solution was 1.42 times that in FA solution, but an opposite result was observed for 316ss, which is consistent with the subsequent chloride-induced corrosion behavior. Steel passive films of different thicknesses and protective characteristics for Q235 and 316ss formed in alkaline solutions were confirmed to be the dominating reason for the distinct passivity and corrosion resistance to chloride attack. Accordingly, the intrinsic impact mechanisms of fly ash on passivation capability and chloride-induced corrosion of Q235 and 316ss in extract solutions were proposed.