CO2-saturated NaCl Solution Research Articles

A Comprehensive Investigation into the Corrosion Mechanism of an Electroless Ni–P Coating in CO2-Saturated NaCl Solution: Degradation or Penetration?

A Comprehensive Investigation into the Corrosion Mechanism of an Electroless Ni–P Coating in CO2-Saturated NaCl Solution: Degradation or Penetration?

Corrosion inhibition properties of sweet crude oil for carbon steel 1018 in NaCl solution

Abstract Aged oil pipeline production systems, historically designed without corrosion protection due to predominantly oil-wetted conditions, now face significant changes as increased water content in produced oil arises from field maturation. This work investigates the corrosion inhibition properties of sweet crude oil on carbon steel 1018 in a CO2-saturated NaCl solution using electrochemical testing (open circuit potential, polarization resistance, electrochemical impedance, potentiodynamic polarization) and surface characterization (SEM, EDS) techniques at 50 °C and pH 6. Carbon steel specimens were immersed in crude oil for durations ranging from 0 to 144 h before undergoing corrosion testing. Results showed that a 144-h immersion in crude oil led to an 88 % reduction in corrosion rate, comparable to the efficiency of standard quaternary ammonium-based inhibitors. Furthermore, a semi-empirical model predicting uniform CO2 corrosion rates for varying oil immersion durations is proposed and validated by comparing its predictions with experimental data from the electrochemical tests.

The corrosion and tribological behaviors of DLC film in CO2 saturated NaCl solution with high Cl− concentration

The failure of pipelines during oil and gas exploitation is a pressing issue in the oil and gas industry. The high permeability of chloride ions (Cl−) alters the corrosion morphology of the N80 substrate and diminishes its ability to impede the penetration of corrosive substances. This study aims to deposit DLC films on the inner surface of N80 pipeline using plasma enhanced chemical vapor deposition (PECVD), and investigate the corrosion and friction behavior of DLC films in CO2 saturated NaCl solutions with varying Cl− concentrations. The results indicate that the change in Cl− concentration possess minimal impact on the DLC film. The corrosion current density of DLC films in CO2 saturated NaCl solution with three different Cl− concentrations is one order of magnitude lower than that of the N80 substrate. Moreover, a transfer film can still form in high-concentration CO2-saturated NaCl solutions, reducing wear. DLC film demonstrates exceptional stability, corrosion resistance, and wear resistance, making it an ideal material for safeguarding pipelines during oil and gas exploitation.

Enhancing wear and corrosion resistance of electroless Ni-P coatings in CO2-saturated NaCl solution through polytetrafluoroethylene incorporation

In the realm of oil and natural gas, material durability is compromised by sand particle abrasion, corrosive media, and hydrogen-induced cracking. This study investigates the impact of PTFE on wear and corrosion resistance of Ni-P coatings in a CO2 environment. Hydrogen barrier properties of the substrate, Ni-P, and PTFE are evaluated using the Devanathan-Stachursky cell. Results show that incorporating PTFE enhances the coating's wear and corrosion resistance, and hydrogen barrier performance compared to substrate and Ni-P alone. The coating effectively hinders corrosive media transmission. A comprehensive analysis of the Ni-P-PTFE corrosion mechanism is provided, along with a robust corrosion model.

Interaction between crevice and galvanic corrosion of X65 carbon steel in the CO2-saturated NaCl solution under the coupling of crevice and galvanic effects

• Crevice corrosion could occur in X65 carbon steel (CS) in CO 2 aqueous environment. • Severe corrosion of X65 CS occurs in the X65 CS-316 stainless steel (SS) couple. • The X65 CS-316 SS galvanic effect inside crevice promotes the corrosion of X65 CS. • Crevice effect inhibits the galvanic corrosion of X65 CS in X65 CS-316 SS couple. In this work, with the self-designed setup, the corrosion of X65 carbon steel (CS) in the CO 2 -saturated NaCl solution containing 600 mg/L HAc under the coupling of crevice and galvanic effects was studied by electrochemical tests, weight loss measurement and surface analysis, and the interaction between the crevice and galvanic effects was quantified. It is found that X65 CS undergoes severe corrosion under individual crevice effect or galvanic effect. The accelerated corrosion by galvanic effect is more significant than that by crevice effect. Under the coupling of crevice and galvanic effects, the galvanic effect between X65 CS and 316 stainless steel (SS) promotes the crevice corrosion of X65 CS because of the anodic polarization, while the crevice effect inhibits the galvanic corrosion between X65 CS and 316 SS because their potential difference is significantly reduced in the presence of crevice effect.

N, S Co-doped carbon coated MnS/MnO/Mn nanoparticles as a novel corrosion inhibitor for carbon steel in CO2-saturated NaCl solution

As the scientific problems aroused in the aspects of interface behavior, colloidal properties and material structures, the novel nano-inhibitors have attracted a lot of attention gradually. Given the diversity of nanomaterials and their structures, the investigations about the inhibition mechanisms of nano-inhibitors besides the traditional adsorption are conducive to improving the basic research of inhibitors discipline system. In this study, N, S co-doped carbon coated MnS/MnO/Mn nanoparticles (MnS/MnO/[email protected]) were synthetized via the sol-gel method and later pyrolysis-sulfurization/oxidation. Diversified measurements have been adopted to investigate the inhibition performance of MnS/MnO/[email protected] for carbon steel in CO2-saturated 3 wt% NaCl solution, and the results confirmed that MnS/MnO/[email protected] can effectively inhibit corrosion, while the inhibition efficiency was more than 90% at 200 mg/L. The various immersion time and addition concentration have been applied to analyze the differences of inhibition effect. From the observation and analysis of surface, lamellar nanomaterials containing the simple substance of Mn have accumulated at interface along with the transformation from MnS to FeS, which were respectively served as anode material and dense corrosion product to protect the carbon steel. Besides that, the accumulations of carbon complex material have formed a hydrophobic film with special micro-nano structures. The probable model of MnS/MnO/[email protected] on metal surface was established to discuss the actual inhibition mechanism.

Electrochemical Corrosion Behavior of API X120 Steel at Different Temperatures in CO2 saturated NaCl solution in presence of 2-[2-(dimethylamino)ethoxy]ethanol as inhibitor

Electrochemical Corrosion Behavior of API X120 Steel at Different Temperatures in CO2 saturated NaCl solution in presence of 2-[2-(dimethylamino)ethoxy]ethanol as inhibitor

Amide functionalized graphene oxide as novel and effective corrosion inhibitor of carbon steel in CO2-saturated NaCl solution

Functionalized graphene oxide (FGO) were synthesized and investigated as corrosion inhibitors of carbon steel in this research. The inhibition behavior of FGO in CO2-saturated NaCl solution was studied via weight loss, surface characterizations, and electrochemical measurements. Results confirm that FGO could protect metal effectively and the inhibition efficiency showed the extreme effect as the increase of FGO concentration, reaching a maximum of 83.4% at 20 mg/L. FGO can adsorb on carbon steel via the functionalized groups and form the hydrophobic cover layer on the metal surface by the lamellar nanoparticles.

Effect of stress on the crevice corrosion of P110 steel in the CO2-saturated NaCl solution containing thiosulphate/H2S

ABSTRACT The effect of stress on the crevice corrosion of P110 carbon steel in the CO2-saturated 3.5 wt-% NaCl solution with a small amount of thiosulphate/H2S was investigated. The results showed that the composition of corrosion products on the steel surface did not change with elastic stress while the mackinawite film formed at the crevice mouth was more easily spalled off under higher stresses. Further, the elastic stress likely promoted localised corrosion but inhibited uniform corrosion both inside and outside crevice. Increasing the applied stress led to a deeper and sharper corrosion groove covering with corrosion products at the crevice mouth, suggesting the crevice corrosion was promoted by the applied stress. This is likely due to the peeling of mackinawite film and stress concentration at the crevice mouth.

Adsorption and corrosion inhibition characteristics of 2–(chloromethyl)benzimidazole for C1018 carbon steel in a typical sweet corrosion environment: Effect of chloride ion concentration and temperature

Benzimidazole derivatives are emerging as promising corrosion inhibitors for oil and gas application because they exhibit high efficiency and very good environmental profile. Although long alkyl and phenyl chains enhance their efficiency, they also increase their toxicity. Finding benzimidazole derivatives devoid of long hydrocarbon chains and with lower toxicity has become a priority. 2–(chloromethyl)benzimidazole (CMB), with log Po/w = 2.2, has been investigated as a promising low-toxic sweet corrosion inhibitor for C1018 carbon steel in CO2–saturated NaCl solution under static condition using experimental and theoretical approaches. At 25 °C, Open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) techniques confirm that CMB is an anodic-type sweet corrosion inhibitor which is able to form a protective layer on the steel surface and provide inhibition efficiency of 97.54% at 10 ppm. The efficiency increased to 98.40% and 98.58% upon increasing the temperature to 40 °C and 60 °C, respectively but decreased to 96.32% and 94.76% as the salt concentration was raised to 5.0% and 7.0% NaCl, respectively. The latter was attributed to the antagonistic competition between Cl– ions and CMB for anodic adsorption. The CMB–steel interaction is facilitated by the free electrons around N heteroatoms and C = C bonds, based on FTIR analysis and computational calculations. This eventually ameliorates the surface degradation of the steel during the sweet corrosion at 25 and 60 °C. CMB performance is highly comparable with reported sweet corrosion inhibitors with higher toxicity values.

Functionalized carbon nanotubes as a novel inhibitor to enhance the anticorrosion performance of carbon steel in CO2-saturated NaCl solution

Functionalized carbon nanotubes (FCNTs) were synthesized by hydrothermal method and adopted as a corrosion inhibitor of carbon steel in CO2-saturated NaCl solution. Results revealed that FCNTs can effectively inhibit carbon steel corrosion, and their inhibition efficiency is close to 90 % at the concentration of 100 mg L−1. FCNTs can adsorb on carbon steel via functionalized groups and make up the hydrophobic layer on the metal surface, which also inhibits the diffusion migration of corrosive mediums as confirmed by molecular dynamics simulation. Adsorption kinetic and thermodynamic isotherm were studied to discuss the difference of FCNTs with traditional inhibitors.

Synergistic Inhibition Effect of Imidazoline and Thiourea: Evidence from Experiments and Molecular Dynamics Simulation

The mass loss method, electrochemical tests, scanning electron microscopy morphology analysis, and molecular dynamics simulation were used to study the synergistic mechanism of imidazoline (IM) and thiourea (TU) on ASTM A106B steel in CO2-saturated NaCl solution. The experimental results clearly revealed that IM and TU had good synergistic corrosion inhibition effect, and the combination of 5 mg/L IM and 5 mg/L TU exhibited the highest inhibition efficiency of 95.1%. Inhibitor molecules replaced the water molecules originally adsorbed on the metal surface and led to inhibition effects. The adsorption of the inhibitor mixtures had a better inhibition effect than individual inhibitors. The adsorption configuration and inhibition performance of the inhibitors demonstrated that the TU molecules first adsorbed on the metal surface to form the first layer, and then the IM adsorbed on TU to form the second layer. The number of water molecules originally adsorbed on the Fe surface decreased, and the diffusion of water molecules in the inhibitor film slowed down, thereby having a synergistic inhibition effect on metal corrosion.

N, S co-doped carbon dots as effective corrosion inhibitor for carbon steel in CO2-saturated 3.5% NaCl solution

Abstract N and S co-doped carbon dots (N, S-CDs) were synthesized and used as corrosion inhibitors for the first time in this study. The inhibition performance of N, S-CDs for carbon steel in CO2-saturated NaCl solution was investigated. Results showed that N, S-CDs can effectively protect carbon steel from corrosion and the inhibition efficiency increases as the concentration of N, S-CDs increases, reaching 93% at 50 mg/L. Even at the low concentration, such as 10 mg/L N, S-CDs, the corrosion current density reduces from 1.472 × 10−4 A·cm−2 in the blank condition to 2.99 × 10−5 A·cm−2 after 12 h immersion. N, S-CDs can adsorb on carbon steel through their functional groups and nanoparticles made up of N, S-CDs can form a hydrophobic film on the metal surface, whose thickness was about 40 nm. A theoretical model is established to describe the inhibition mechanism of N, S-CDs.

Electrochemical Investigation of Corrosion of X80 Steel under Elastic and Plastic Tensile Stress in CO2 Environment

An investigation into the electrochemical corrosion behavior of X80 pipeline steel under different elastic and plastic tensile stress in a CO2-saturated NaCl solution has been carried out by using open-circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopy, and surface analysis techniques. The results show that the corrosion rate of X80 steel first increases and then slightly decreases with the increase of elastic tensile stress, whereas the corrosion rate sharply increases with the increase of plastic tensile stress. Both elastic and plastic tensile stress can enhance steel corrosion by improving the electrochemical activity of both anodic and cathodic reactions. Moreover, compared with elastic tensile stress, plastic tensile stress has a more significant effect. Furthermore, electrochemical reactions for CO2 corrosion and mechanoelectrochemical effect are used to reasonably explain the corrosion behavior of stressed X80 steel in CO2 environment.

Effect of defect on corrosion behavior of electroless Ni-P coating in CO2-saturated NaCl solution

The effects of defect on the localized corrosion and disbonding behavior of electroless Ni-P coating in CO2 environment were investigated using electrochemical methods and surface characterization techniques. The results show that the Ni-P coating has a good resistance to corrosion disbonding at open circuit potential, even with an artificial defect in the coating. The localized corrosion and the disbonding of the coating occur after the acceleration by cathodic polarization because the coating defects provide effective pathways for the electrolyte to transport through the coating and along the coating/substrate interface laterally. A corrosion model is proposed to well interpret this phenomenon.

The role of acetic acid or H+ in initiating crevice corrosion of N80 carbon steel in CO2-saturated NaCl solution

The role of acetic acid (HAc) or H+ in initiating the crevice corrosion of N80 carbon steel in CO2-saturated NaCl solution was studied by weight loss and electrochemical measurements. It is demonstrated that crevice corrosion could be initiated by the concentration difference either HAc or H+ between outside and inside the crevice. The corrosion rate inside the crevice becomes higher than that outside the crevice and the total corrosion rate inside and outside the crevice decreases after connection. Crevice corrosion is more severe in the solution with HAc than that in the solution with H2SO4 at the same pH value.

Inhibition effect of imidazoline inhibitor on the crevice corrosion of N80 carbon steel in the CO2-saturated NaCl solution containing acetic acid

Inhibition effect of imidazoline (IM) inhibitor on the crevice corrosion of N80 carbon steel in CO2-saturated NaCl solution containing acetic acid (HAc) was investigated by weight loss and electrochemical measurements, and surface analysis. The inhibition effect in the solution with 3g/L HAc, where IM as a mixed-type inhibitor with predominant cathodic effectiveness, is more prominent than that in the solution with 1g/L HAc, where IM as a mixed-type inhibitor with predominant anodic effectiveness. IM can inhibit the crevice corrosion of the steel when added at the beginning, but not when added after corrosion for a period of time.

Formation of Nano-Scale FeCO<sub>3</sub> Protective Corrosion Product in Carbon Dioxide-Saturated 3% Sodium Chloride Solution

Corrosion of carbon steel in CO2 saturated NaCl solution contains the formation of FeCO3, as a corrosion product. The protective property of the formed FeCO3 scale layer to corrosion in brine solutions containing CO2 was established as the possible cause of the corrosion rate decrease above 60 °C. In this study, formation of nanoscale FeCO3 film as a corrosion product of X52 carbon steel in CO2-Saturated 3% NaCl solution was investigated. Result showed that corrosion rate decreased after precipitation and formation of protective FeCO3 film in high temperature and high bulk solution pH.

Synergistic effect of stress and crevice on the corrosion of N80 carbon steel in the CO2-saturated NaCl solution containing acetic acid

The corrosion behaviour of N80 carbon steel under the coexistence of stress and crevice in the CO2-saturated NaCl solution containing acetic acid (HAc) was studied by electrochemical measurements, surface analysis, and stress analysis. It is demonstrated that the corrosion potential of steel shifts negatively and corrosion activity is enhanced with increasing stress. A deep corrosion groove is formed at crevice mouth, which causes stress concentration, increasing the susceptibility to stress corrosion cracking (SCC). The stress concentration also results in larger driving force for crevice corrosion. Therefore, there is a synergistic effect of stress and crevice on the corrosion of steel.

Effect of Cl<sup>-</sup> Content, pH Value and CO<sub>2</sub> on Electrochemical Corrosion Features of Cr15 Super Martensitic Stainless Steel

The corrosion behavior of a Cr15 super martensitic stainless steel (Cr15 SMSS) was investigated in NaCl solutions by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Effects of Cl-content, pH value and saturated CO2on corrosion were sdudied. It was found that the parameters of maintaining passivity current density (ip), the critical pitting potential (Eb) and charge transfer resistance (Rt) of Cr15 SMSS varied widely under different conditions. The corrosion resistance of Cr15 SMSS decrease with increasing Cl-concentration and lowering pH value. BothipandEbincrease for Cr15 SMSS in CO2-saturated NaCl solution, which verified that the CO2in NaCl solution can result in lower pitting sensitivity and higher uniform corrosion rate to Cr15 SMSS.