Steel In Seawater Research Articles

Influence of temperature on the cathodic polarization behavior and calcareous deposit properties of X65 steel in sea water

PurposeThis paper aims to investigate how cathodic polarization behavior significantly affects the selection of cathodic protection parameters and the effectiveness of protecting underwater metal structures. Factors such as water depth and operating conditions impact seawater temperature, making it crucial to understand the effects of temperature on cathodic protection parameters for underwater pipelines.Design/methodology/approachIn this paper, potentiostatic polarization was carried out by three-electrode method, and morphology, X-ray diffraction and electrochemical analysis.FindingsIt was determined that the stable current densities at the minimum negative potential (−0.8 VSSC) for pipeline steel varied at different temperatures: 7°C, room temperature and 60°C. The cathodic protection potential corresponding to the lowest stable current density was observed to be −1.0 VSSC at 7°C and −0.95 VSSC at room temperature and 60°C.Originality/valueThis study elucidates the mechanisms by which different temperatures affect the protective performance of calcareous deposits and current densities.

Influence of Carboxymethyl Chitosan and Sodium Humate Composite Corrosion Inhibitor on the Corrosion Resistance of EH40 Steel in Seawater.

In this study, corrosion weight loss experiments were conducted to explore the corrosion-inhibiting properties of a composite inhibitor consisting of carboxymethyl chitosan (CMCS) and sodium humate (SH) at varying concentrations on EH40 steel in seawater. An investigation was conducted into the electrochemical behavior of EH40 steel in seawater and the mechanism of composite inhibitor consisting of carboxymethyl chitosan (CMCS) and sodium humate (SH) at varying concentrations on EH40 steel in seawater through an electrochemical test. X-ray photoelectron spectroscopy (XPS), scanning electron microscopy and energy-dispersion spectroscopy (SEM-EDS), Fourier transform infrared absorption spectroscopy (FTIR), and contact angle measurements were performed to confirm the mechanism of CMCS and SH as well as their composite corrosion inhibitors at the interface between seawater and EH40 steel. Furthermore, density functional theory (DFT) calculation supports the experimental findings. The results show that CMCS, SH, and their composite inhibitor are a mixed type of corrosion inhibitor that mainly inhibits cathodic reactions and corrosion through the active site blocking mechanisms. Their corrosion inhibition effect increases with the increase of mass concentration, and the composite inhibitor performs better in corrosion inhibition and scale inhibition than the individual inhibitor. When the CMCS mass concentration reaches 100 mg/L and the SH mass concentration reaches 50 mg/L, the corrosion inhibition rate is 74.65%, the corrosion potential shifts by about 47.39 mV, the Rp value increases from 358.6 to 1102.4 Ω·cm2, and the Ydl value decreases from 177.31 Sn Ω-1cm-2 × 10-6 to 92.672 Sn Ω-1cm-2 × 10-6. CMCS and SH are adsorbed onto the surface of EH40 steel, forming a protective film through the complexation of carboxyl, amino, and other functional groups to inhibit corrosion and prevent the further formation of scale. In addition, synergistic coadsorption occurs between CMCS and SH, and the composite corrosion inhibitor exerts a better effect than the individual corrosion inhibitor.

Performance of Acetone Extract of Anthocleista grandiflora as a Potential Bioinhibitor on Corrosion Behavior of Carbon Steel in Seawater Environment

In this study, we evaluated the potential of Anthocleista grandiflora leaf (AGL) plant extract as an environmentally friendly and cost-effective corrosion inhibitor for carbon steel in seawater. We employed various experimental methods, including gravimetric analysis, potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometry (FTIR). Our findings indicate that increasing the concentrations of the AGL extract results in higher charge transfer resistance (Rct ) and reduced double-layer capacitance (Cdl ), suggesting the effective adsorption of AGL extract on the surface of carbon steel. The inhibition efficiencies were notably high, 98.7%, 92.40%, and 90.7% determined with gravimetric analysis, potentiodynamic polarization, and electrochemical impedance spectroscopy, respectively. Polarization analysis revealed that the AGL extract acted as a mixed-type inhibitor. Moreover, the results obtained from different techniques exhibited a consistent agreement. The SEM images revealed that the surface layer formed by the AGL extract on the mild steel surface further devoids the surface from pitting as the extract concentration increases. Comparative analysis with similar bio-based inhibitors suggested that the tested AGL extract holds a significant promise as a corrosion inhibitor for carbon steel in seawater. Therefore, our findings support the recommendation of utilizing this AGL extract as an effective anti-corrosion agent in marine industries, owing to its green, low-cost, and efficient characteristics.

Numerical Analysis of Stainless Steel of Crevice Corrosion Initiation Behavior with Varying External Potentials and Initial Crevice Gaps

The potential, current density, pH, and crevice profile distribution within the crevice structure of stainless steel in seawater were numerically analyzed. The crevice corrosion phenomena were mathematically modeled with the initial boundary value problem of diffusion and static electrical field, respectively. This initial boundary value problem was discretized using a finite difference method. The predicts of the crevice corrosion behaviors, set for various external potentials and initial crevice gaps, were classified into three categories: the pitting type, the active type, and no corrosion. The pitting type crevice corrosion was predicted to occur in conditions where the external potentials were noble and the initial crevice gaps were narrow. The active type crevice corrosion was predicted to occur in conditions where the external potentials were less noble and the initial crevice gaps were narrow. The range of external potential conditions where crevice corrosion was predicted not to occur increased in conditions with wide initial crevice gaps. Crevice corrosion was predicted to occur at all external potentials in conditions where the initial crevice gaps were 2 μm or less.

Corrosion Resistance of Cr10Mo1 Alloy Corrosion-Resistant Steel in Seawater–Sea Sand Concrete Pore Solution

Corrosion Resistance of Cr10Mo1 Alloy Corrosion-Resistant Steel in Seawater–Sea Sand Concrete Pore Solution

Humic acid as eco‐friendly corrosion inhibitor for EH40 ship plate steel

In this study, a new type of green corrosion inhibitor, namely, sodium humate (SH), was extracted from humus soil, which is a natural humus plant, by dissolution‐neutralization, and then used for corrosion inhibition of low carbon steel in seawater. The corrosion inhibition performance of SH on low carbon steel EH40 in seawater was tested by weight loss method and electrochemical technology. The surface and corrosion products of low carbon steel were observed and analyzed by scanning electron microscope (SEM), atomic force microscope (AFM), contact angle and X‐ray photoelectron spectroscopy (XPS). The results show that SH is a mixed corrosion inhibitor, and the optimum concentration is 2 g L−1. At this concentration, the inhibition rate can reach 93.6%. It mainly affects the semi‐reaction of cathodic corrosion. By forming a corrosion protection layer with uniform adsorption on the surface of EH40 steel, EH40 steel becomes more resistant to seawater corrosion.

The Corrosion Behaviors of X70 Steel Under the Effect of Alternating Current and Sulfate-Reducing Bacteria in Seawater

The influence of alternating current (AC) and sulfate-reducing bacteria (SRB) on the corrosion behaviors of X70 steel in seawater was investigated by different electrochemical tests and surface examination methods. It was found that the activity of SRB was affected by AC. When the AC current density sustains at the low level of 0 A/m2 and 50 A/m2, the activity of SRB is not high enough to produce a significant impact on the AC-induced corrosion process. As the current density increases to 80 A/m2 and 100 A/m2, SRB could alter the corrosion kinetics by forming a more intact film on the corrosion surface. However, the activity of SRB is inhibited by AC with the current density up to 200 A/m2. The intact corrosion product formed by SRB in high activity could influence the AC corrosion kinetics, but the product film can not prevent AC-induced corrosion. The localized corrosion was more significant under the effect of AC and SRB probably because the biofilm formed by SRB produced uneven electrochemical properties on the corrosion surface.

REASON OF PITTING CORROSION OF MARTENSITIC STEELIN SEA WATER

Abstract. The assumption that corrosion of products from X17 martensitic stainless steel in seawater occurs due to incomplete oxidation of chromium atoms in cells on the surface of the products is made in the presented work. Incomplete oxidation of chromium atoms occurs in the cells of X17 steel. This is due to the fact that oxygen molecules at temperatures up to 350 °C not having enough energy for chemical interaction with trivalent chromium atoms entering the cubic body-centeredcells of martensitic stainless steel. There is a significant decrease in the corrosion rate after placing X17 stainless steel products in 5% iodine solution in ethanol after pre-treatment of the product surface with active forms of oxygen. The treatment was carried out during 12 hours with chemically active forms of oxygen (ozone and singlet oxygen) at a temperature of 350 °С. Most of the chromium atoms on the surface of X17 steel samples were completely oxidized as a result of 12 hours exposure to highly active forms of oxygen. The density of the oxide passivation layer on the surface of the products increased significantly as a result of the formation of new bonds CHROMIUM -OXYGEN -CHROMIUM. This resulted in increased corrosion resistance. The rate of interaction with an alcohol solution containing halogen ions was reduced by 71% for the samples with the oxide passivation layer compared to samples of untreated X17 steel.

EFFECT OF MICRO-TEXTURES AND CrAlSiN COATINGS ON THE FRICTION AND WEAR PROPERTIES OF 316L STAINLESS STEELS IN SEAWATER

This paper aims to provide a method for improving the tribological properties of 316L stainless steels in seawater. During the experimental process, laser texturing technology was used to create biomimetic micro-textures inspired by turtle shell patterns on the 316L stainless steel surfaces. Then, CrAlSiN coating was deposited on the textured surface using the physical vapor deposition (PVD) technique, allowing us to study the frictional properties of the samples in both atmospheric and seawater environments. The results showed that, compared to polished 316L stainless steel, the specimens treated with micro-texture and CrAlSiN coating exhibited a reduction in wear rate by 52.1% and 71.8% under atmospheric and seawater friction conditions, respectively. Under atmospheric friction conditions, the micro-textures had a limited effect on reducing the friction of the 316L stainless steel substrate. However, the CrAlSiN coating, due to its excellent mechanical properties, significantly improved the wear resistance of the 316L stainless steel. Under seawater friction conditions, the continuous CrAlSiN coating played a role in reducing 316L stainless steel wear and seawater corrosion. At the same time, the micro-textures acted as reservoirs for wear debris and seawater, forming a more stable seawater lubricating film and reducing the friction coefficient. Therefore, the synergistic effect of the CrAlSiN coating and biomimetic micro-textures demonstrated remarkable improvement in the tribological performance of 316L stainless steel in seawater environments.

Impact of Co3O4 nanoparticles on epoxy's mechanical and corrosion-resistance properties for carbon steel in seawater

Co3O4 nanoparticles (Co3O4-NPs) are synthesized using the facile solvothermal method. FT-IR and XRD spectroscopic analyses verify the creation of cobalt oxide nanoparticles with an average size of 13.20 nm. Furthermore, Zeta potential assessments were carried out to identify the electrical charge of the surface of the produced Co3O4-NPs, which was found to be -20.5 mV. In addition, the average pore size of Co3O4-NPs is 19.8 nm, and their BET surface area is 92.4 m/g. The study also concerned the effect of Co3O4-NPs on epoxy's improvement of mechanical and corrosion protection for carbon steel in salt solution. By including Co3O4-NPs in an epoxy (EP) coating, corrosion is effectively prevented by non-permeable protective coatings that effectively reduce the transfer of corrosion ions and oxygen.

Corrosion film breakdown of galvanized steel in seawater below 25 °C

Corrosion film breakdown of galvanized steel in seawater below 25 °C

Examining the ability of palm kernel shell extract to control corrosion and assess its economic value on thermo-mechanically treated steel in artificial seawater: a sustainable and environmentally friendly approach.

Each year, the rising demand for palm oil generates large amounts of palm kernel shell waste. Discarded palm kernel shells can produce activated carbon, crushed shells, liquified fumes, and other derivatives; however, their indiscriminate disposal persists, raising issues related to the environment and economy. Therefore, the purpose of this study is to investigate the use of palm kernel shell as a corrosion inhibitor for thermo-mechanically treated steel in a seawater environment using gravimetric and electrochemical techniques, as well as surface tests at varying concentrations. The findings demonstrated that the palm kernel shell inhibited the cathodic and anodic processes by adsorption on the steel surface, which followed the Langmuir adsorption isotherm. The inhibitor exhibited a 98% inhibitory efficiency at 500ppm concentration. Scanning electron microscopy analysis verified the thin films of the inhibitor on steel surface in seawater solution. Fourier transform infrared spectroscopy results show that the extract's components prevent the steel corrosion through an adsorptive mechanism. According to the inhibitor economic evaluation, employing the palm kernel shell extract is less expensive than utilizing conventional inhibitors.

Development of Al-Mg Alloy for the Protection of Steel Structure in 3.5% Nacl

Aluminium (Al) is thoroughly used as a sacrificial metal for the protection of steel in seawater. Aluminium is rarely used as a sacrificial anode without being alloyed due to its built-in properties to get passivates and form a passive layer and the continuity of its layer depends on the chemical composition and microstructure. In this paper, Aluminium-Magnesium(5xxx) system is considered because magnesium remarkably affects the chemical properties by changing the microstructure of Aluminium from a homogeneous solid solution to a complex structure with multiple intermetallic phases. In this research work developing Aluminium-Magnesium alloys containing 2.5 and 4.5 weight percent magnesium. The microstructures of pure aluminium and developed alloys were studied and the effect of the distribution of magnesium whether as a second phase particle, intermetallic compound or precipitates on the performance of aluminium sacrificial anode was discussed. Standard weight loss method and potentiodynamic tests are used to evaluate the performance of alloy sacrificial anode. The result shows that as the magnesium content increases corrosion rate of developed alloy increases and corrosion potential shifts in more negative directions. Corrosion potential is increased by 250 mV at 4.5% magnesium because of the formation of an intermetallic compound of aluminium& Magnesium (β phase - Al3Mg2) at the grain boundary. Magnesium improves the corrosion rate of developed alloy,it acts as a depassivators for the passive film of Aluminium by forming intermetallic compound and this compound has different electrochemical properties that leads to corrosion of aluminium and improves the performance of aluminium sacrificial anode.

Crevice Corrosion of High-Grade Stainless Steels in Seawater: A Comparison Between Temperate and Tropical Locations

The corrosion risk for stainless steel components is not the same in all seawaters, with more failures generally reported in tropical seas. In this study, the influence of biofilm on electrochemical behavior and corrosion resistance of passive films of high-grade alloys was studied in different seawaters, including temperate seawater (France-Brest, North Atlantic Ocean), tropical seawater (Malaysia-Kelatan, Meridional China Sea), and intermediate conditions in terms of temperature (Brazil-Arraial do Cabo, South Atlantic Ocean). The stabilized open-circuit potentials and the polarization behavior of high-grade stainless steels were measured as a function of temperature in all of the tested field marine stations, providing quantified data and direct comparison of the biofilm-enhanced corrosion risks. Significant differences were measured in tropical and in temperate seawaters in heated conditions. Above 37°C, the biofilm activity was much more pronounced in tropical seawater compared to Atlantic Ocean sites, leading to much higher localized corrosion risk. Crevice corrosion of eight high-grades passive alloys was also studied with the use of crevice formers specifically developed for tube geometries. Duplex UNS S32205, superduplex UNS S32750, hyperduplex UNS S33207 and S32707, and 6Mo stainless steels UNS S31266 have been evaluated together with Ni-based alloys UNS N06845 and N06625. In the more severe conditions, the high-grade alloys UNS S32707 and the 6%Mo UNS S31266, both with pitting resistant equivalent number (PREN) around 50, showed better performance than commonly used superduplex UNS S32750 and UNS S39274 (PREN 40). The corrosion results are discussed regarding the monitored biofilm-induced depolarization measured in the different test conditions.

Effects of Lorentz Force and Gradient Force of Magnetic Field on the Seawater Corrosion Behavior of Carbon Steels

With the rapid development of modern civilization, the development of marine resources has become imminent, but seawater corrosion has become one of the most important factors hindering development. In order to overcome this problem, an environmentally friendly physical anticorrosion scheme based on a magnetic field () has been proposed. In this context, we investigate the effect of the Lorentz force and gradient force of a magnetic field on the corrosion behavior of carbon steel in seawater. The experimental results show that the gradient force of a magnetic field inhibits corrosion while the Lorentz force promotes corrosion. Especially in the (corrosion electrical field) case, the Lorentz force influence on the corrosion behavior is greater than the gradient force, while in case gradient force dominates. In addition, the effect mechanism of magnetic field on the corrosion behavior of carbon steel in seawater was revealed by comparison of corrosion product composition in different reaction regions and electrochemical impedance spectrum analysis, which will provide an experimental basis for the application of environmentally friendly marine anticorrosion technology based on a magnetic field.

Corrosion Behavior of Stainless Steel in Seawater in the Presence of Sulfide

The effect of temperature (from 288 to 308 K) and concentration of sulfide ions (up to 40 ppm) on the corrosion behavior of AISI 304L and AISI 316L stainless steels in seawater was studied with measurements of open-circuit potential, linear and potentiodynamic polarization, and electrochemical impedance spectroscopy. An increase in temperature and pollutant concentration negatively affects the corrosion stability of stainless steels at the open circuit (the resistance, compactness, and thickness of the surface layer decrease and the corrosion current increases), in the passive region (the passivation current increases, the depassivation potential decreases, and the passive potential region narrows), and in the transpassive potential region (the rate of metal dissolution increases). The occurrence of pitting corrosion on the surface of the samples was confirmed with optical microscopy and a non-contact 3D profilometer. A few large pits (depth 80–100 μm and width 100 μm) were formed on the surface of AISI 304L steel, while several smaller pits (depth 40–50 μm and width 50 μm) were formed on the surface of AISI 316L steel. With increasing temperature and sulfide ion concentration, the width, depth, and density of the pits increased on both steel samples. In the studied temperature and concentration range of sulfide ions, the AISI 316L steels exhibited higher corrosion resistance. Overall, the influence of sulfide ions on steel corrosion was more pronounced than the influence of temperature.

Effects of AC interference on the corrosion behavior of X70 steel in seawater and acidic solutions

Effects of AC interference on the corrosion behavior of X70 steel in seawater and acidic solutions

Fretting Wear Characteristics of SLM-Formed 316L Stainless Steel in Seawater

The fretting wear characteristics of two different energy density 316L stainless steels formed by selective laser melting (SLM) under different friction conditions are studied. The image method was used to study the porosity of two samples with different energy densities (46.88 J/mm3, 98.96 J/mm3) formed by SLM. The dynamic wear test, respectively, evaluates its wear morphology and wear depth under three conditions: dry friction, distilled water, and an 3.5% NaCl solution. The porosity of the samples with SLM forming an energy density of 46.88 J/mm3 and 98.96 J/mm3 are 7.66% and 1.00%, respectively. Under the three conditions, the friction coefficient and wear depth of the samples with high energy density are smaller than those of the samples with low energy density; the friction of the samples with two energy densities in aqueous solution is faster than dry friction in air and tends to be stable. The friction coefficient in 3.5% NaCl solution is the smallest; when the energy density is constant, the wear depth of the fretting wear is the largest under dry friction and the smallest in distilled water. Under dry-friction conditions, the wear mechanisms of fretting wear are mainly oxidative wear and adhesive wear. In the fretting wear in the distilled water and the 3.5% NaCl solution, both wear mechanisms are abrasive wear and fatigue wear.

Effect of Pseudomonas sp. on simulated tidal corrosion of X80 pipeline steel

Microbiologically influenced corrosion of pipeline steel in seawater has long been concerned by scholars all over the world, but there were few reports on the microorganism effect on marine tidal corrosion of steels. In this work, the effect of Pseudomonas sp. on static tidal corrosion of X80 pipeline steel were systematically studied using weight-loss, Fourier transform infrared spectroscopy (FTIR), electrochemical measurements, scanning electron microscopy (SEM) and ultra-deep field 3D microscope. The results manifested that after 720 h exposure to the marine tidal environment, the sessile Pseudomonas sp. counts multiplied with the elevation increase. The corrosion style of the steel in the inoculated environment was mainly localized corrosion. As a consequence of the higher bacteria number, the corrosion rate, pit depth and corrosion product thickness collectively enhanced. Pseudomonas sp. significantly accelerated uniform and localized corrosion of the steel in the marine tidal zone, and the acceleration role enhanced with the steel elevation in the tidal zones.

Mechanistic investigations of corrosion and localized corrosion of X80 steel in seawater comprising sulfate-reducing bacteria under continuous carbon starvation

Sulfate-reducing bacteria (SRB) corrosion is one of the main reasons leading to the service failure of engineering materials in the marine environment. An understanding of SRB corrosion especially under continuous organic carbon starvation is required. In this work, SRB corrosion of X80 pipeline steel under continuous organic carbon starvation was studied using mass loss, electrochemical measurements, and surface analysis. The effects of initial SRB concentrations on steel corrosion were also studied and discussed. The results indicated that more than 99% population of SRB die after 21 d of testing in various conditions, but there are still amounts of SRB survivors. SRB survivors with continued organic carbon starvation have a better adaptive ability and accelerated steel corrosion. Both the uniform and localized corrosion rates are also proportional to the initial SRB concentration as well as SRB survivors. The localized corrosion rate and density of corrosion pits of specimen corresponding to an initial SRB count of 108 cells/mL reach bigger values of (0.693 ± 0.114) mm/y and (1.94 ± 0.39)×104 pits/cm2, respectively, which are induced by the combination of the sessile and planktonic SRB.