Steel In Simulated Seawater Research Articles

Adhesion of different types of extracellular polymeric substances from Pseudomonas aeruginosa to enhance/inhibit corrosion of EH40 steel in simulated seawater

The corrosion behavior of three types of EPS of Pseudomonas aeruginosa, i.e., soluble, loosely bound, and tightly bound EPS (S-EPS, LB-EPS, and TB-EPS) on the surface of EH40 steel were studied. Results indicated that three EPS have distinct adhesion mechanisms and corrosion influence on EH40 steel. S-EPS with an inhibitory effect on corrosion interact with EH40 steel through electrostatic force, whereas LB-EPS and TB-EPS can promote corrosion due to their stronger adhesion forces provided by hydrogen and coordination bonds.

Carbon nitride interlayer-enhanced TiO2/WO3 nanorods with surface oxygen vacancies for durable photocathodic performance on 304 stainless steel in simulated seawater

To achieve a long-term photocathodic protective effect on metals in the marine environment, efficient charge mobility and electron storage are essential. Herein, we develop an oxygen vacancy (VO)-involved TiO2-wrapped WO3 nanorod composite by PPy-derived carbon nitride interlayer (TiO2/CNx/WO3) for the photoelectrochemical cathodic protection of 304SS in 3.5 % NaCl solution. The introduced CNx can serve not only as an electron channel to accelerate carrier migration but also as an efficient reductant to generate VO at the interfaces of TiO2 and WO3 during crystallization. The incorporated VO tunes the electronic structure and produces the mid-gap states, which lower the energy barrier for electron-hole separation. Meanwhile, WO3 nanorods as an electron self-storage pool make the photocathodic protection functional in darkness. Consequently, the as-prepared TiO2/CNx/WO3 photoanode yields a photocurrent density of 18.23 μA·cm−2 and a photoinduced cathodic polarization potential of −306 mV in simulated seawater. Even in the absence of light illustration, it can polarize 304SS to approximately −200 mV and continuously to 300 mV after 12h. This work will offer a universal strategy for the rational design and fabrication of highly efficient semiconductor composite materials in the field of photocathodic anticorrosion.

Critical role of slags in pitting corrosion of additively manufactured stainless steel in simulated seawater

Pitting corrosion in seawater is one of the most difficult forms of corrosion to identify and control. A workhorse material for marine applications, 316L stainless steel (316L SS) is known to balance resistance to pitting with good mechanical properties. The advent of additive manufacturing (AM), particularly laser powder bed fusion (LPBF), has prompted numerous microstructural and mechanical investigations of LPBF 316L SS; however, the origins of pitting corrosion on as-built surfaces is unknown, despite their utmost importance for certification of LPBF 316L SS prior to fielding. Here, we show that Mn-rich silicate slags are responsible for pitting of the as-built LPBF material in sodium chloride due to their introduction of deleterious defects such as cracks or surface oxide heterogeneities. In addition, we explain how slags are formed in the liquid metal and deposited at the as-built surfaces using high-fidelity melt pool simulations. Our work uncovers how LPBF changes surface oxides due to rapid solidification and high-temperature oxidation, leading to fundamentally different pitting corrosion mechanisms.

Unveiling the corrosion inhibition efficacy and stability of silver nanoparticles synthesized using Anacardium occidentale leaf extract for mild steel in a simulated seawater solution.

Plant extracts used as corrosion inhibitor for mild steel usually degrade as the temperature increases above room temperature. In this study, we used Anacardium occidentale (cashew leaf) extract to synthesize silver nanoparticles for improving mild steel's inhibition stability under salinized conditions. Cashew leaves were used as a reducing agent to synthesise silver nanoparticles. The functional group of the silver nanoparticles was determined using Fourier transform infrared spectroscopy. Electrochemical impedance spectroscopy and potentiodynamic polarisation were used to study the corrosion behaviour under simulated seawater by varying the silver nanoparticle concentration between 0.1 and 0.3 g L-1. Scanning electron microscopy and atomic force microscopy were used to obtain information about the surface of the corroded sample. The green silver nanoparticles reduced the corrosion of mild steel up to 90.5% at 40 °C and 90% at 80 °C. At 80 °C, the AgNPs are biochemically and thermally stable, exhibiting a 90% inhibition efficiency. It was established that silver nanoparticles from cashew leaves can be used to improve the stability of mild steel in simulated seawater.

Insights into the corrosion resistance of Thaumatococcus daniellii on carbon steel in simulated sea water: Experimental and machine learning prediction

The present work compared the predictive abilities of response surface methodology (RSM) and adaptive neuro fuzzy inference systems (ANFIS) in modeling of carbon steel corrosion inhibition by Thaumatococcus daniellii leaf extract (TDE). Thaumatococcus daniellii leaf extract was examined using Fourier Transform Infrared Spectroscopy (FTIR) methods which revealed that the phytochemical components present in TDE has high-value flavonoids, tannins, and dominating functional groups needed to support long-term corrosion inhibition. Error indices revealed the superiority of ANFIS (R2 = 0.99443) and RSM (R2 = 0.98932) in predicting the inhibition efficiency of carbon steel corrosion, while statistical metrics confirmed the application of RSM and ANFIS techniques in modeling the corrosion inhibition of carbon steel. Weight loss and electrochemical, methods were used to validate the predictive abilities of RSM and ANFIS. In addition, the carbon steel surface was examined post immersion using fourier transform infrared spectroscopy (FTIR), UV–Visible spectroscopy, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), and atomic force microscopy (AFM). According to the results, the optimal values of the percentage inhibition efficiencies (IE%) of TDE from weight loss, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) were found to be in close relationship as 88 %, 86 %, and 81 %, respectively, at a concentration of 2.0 g/L. TDE was confirmed to function as a mixed-type corrosion inhibitor according to potentiodynamic polarization results. The results of the machine learning are in line with the experimental findings.

Corrosion wear behavior of 30CrNi2MoVA steel in simulated seawater

This study investigates the corrosion wear behavior of 30CrNi2MoVA steel in a simulated seawater environment using an electrochemical workstation and a friction-wear testing machine. The results indicate that under dry friction conditions, an increase in load leads to an increase in friction coefficient and wear depth. In seawater, an increase in speed results in a decrease in friction coefficient and an increase in wear depth, while the effect of load on material loss is minimal, highlighting the crucial role of speed in corrosion-wear behavior. The synergistic effect of corrosion and wear causes more severe damage than dry friction. The corrosion wear behavior of 30CrNi2MoVA steel is a dynamic process of “mechanical deoxidation-chemical reoxidation,” as evidenced by the change in corrosion potential from −0.6502 V to −0.8646 V and increased material loss.

Binder-integrated Bi/BiOI/TiO2 as an anti-chloride corrosion coating for enhanced photocathodic protection of 304 stainless steel in simulated seawater

Preparing Bi/BiOI catalysts for efficient photocathodic protection of metals in the marine environment has been always a tricky problem because of Bi oxidation and I- ion release under Cl- ion corrosion. Herein, by integrating sodium carboxymethyl cellulose (CMC) into the composites, petal-like Bi/BiOI-modified TiO2 (TBB) p-n heterostructure coatings with a "truncated schema" were successfully fabricated. The as-prepared coatings (CTBB) provided stable photocathodic protection for 304 stainless steel (304SS) in simulated seawater. Compared with TiO2, CMC integrated Bi/BiOI/TiO2 p-n heterostructure coatings showed enhanced photocathodic protection performance with a large photocurrent response of 43 μA cm−2 and a stable potential drop of − 250 mV in simulated seawater without the participation of hole scavengers, which was attributed to the improvement of visible-light utilization and fast electron-hole pair migration at the p-n heterojunction interface. Furthermore, CMC effectively protected Bi nanoparticles against oxidation and BiOI from corrosion of Cl- ions in the electrolyte due to electron density redistribution in the vicinity of I- ions. The as-fabricated CTBB coatings showed great potential as photoanodes for photocathodic protection of 304SS in simulated seawater.

A Comparison of Vertical Electro-Gas Welding and Submerged arc Welding Methods on the Corrosion Behaviors of Crude Oil Storage Tank Steel in Simulated Seawater

A Comparison of Vertical Electro-Gas Welding and Submerged arc Welding Methods on the Corrosion Behaviors of Crude Oil Storage Tank Steel in Simulated Seawater

Coupling Effect of Hydrostatic Pressure and Erosion on Corrosion Behavior of X70 Steel in Simulated Seawater.

The corrosion behavior of X70 steel under the coupling effect of pressure and erosion in simulated seawater was investigated by using corrosion loss, electrochemical tests, SEM, AFM, XPS, and Raman spectroscopy. The coupling effect of pressure and erosion could induce changes in the amounts and compositions of the corrosion products and increase pitting. The rate of the combined corrosion of X70 steel represents a downtrend, which still displays a higher corrosion rate than only immersion at the same pressure. This means that the coupling of pressure and erosion will accelerate corrosion, but the effect of erosion is weakened by pressure. The larger the pressure is, the more erosion is weakened. The pressure reduces the water cutting force by increasing the liquid viscosity and reduces the surface hardness changes under high pressure by generating magnetite, which is closely bound to the substrate.

Accelerated deterioration mechanism of 316L stainless steel in NaCl solution under the intermittent tribocorrosion process

In this research, the tribocorrosion behavior of 316L stainless steel in simulated seawater was investigated under continuous and intermittent sliding at open circuit potential. The tribocorrosion mechanism was discussed in terms of wear morphologies, mechanical property as well as chemical composition. Meanwhile, microstructure evolution inside the wear track and open circuit potential recorded after sliding were analyzed to quantify the repassivation kinetics and evaluate the impact of the regenerated passive film on wear. The results showed that the wear rate increased under intermittent sliding when the pause time is long enough to repassivate after sliding. Repeated sliding promoted the refinement of the grain inside the sliding area, which was beneficial to the generation of the thicker and more compact passive film inside the wear track. The ruptured passive film often acted as abrasives during subsequent sliding. Therefore, the accelerated material loss under intermittent sliding was attributed to the periodic mechanical removal of the thickened passive film and the enhanced abrasive wear inside the wear track.

Rhamnolipid as an eco-friendly corrosion inhibitor for microbiologically influenced corrosion

The development of sustainable and non-toxic corrosion inhibitors attracts much attentions. Herein, the rhamnolipid (RH) produced by Pseudomonas aeruginosa was found to effectively inhibit the corrosion of X70 carbon steel in simulated seawater. Moreover, RH was verified to protect X70 carbon steel against the microbiologically influenced corrosion (MIC) caused by Bacillus licheniformis, a typical corrosive bacterium. The addition of 0.1% (m/v) RH reduced the corrosion current density by 68.4% in the presence of B. licheniformis compared with untreated condition. The growth of B. licheniformis was significantly inhibited with RH concentration higher than 125 mg/L. The antimicrobial and corrosion inhibition effects make RH suitable for MIC inhibition.

Effect of cathodic potential on stress corrosion cracking behavior of 21Cr2NiMo steel in simulated seawater

Effect of cathodic potential on stress corrosion cracking behavior of 21Cr2NiMo steel in simulated seawater

Corrosion Fatigue Mechanism of Welded Eh36 Steel in Simulated Seawater and Under Cathodic Protection

Corrosion Fatigue Mechanism of Welded Eh36 Steel in Simulated Seawater and Under Cathodic Protection

Corrosion Fatigue Mechanism of Welded Eh36 Steel in Simulated Seawater and Under Cathodic Protection

Corrosion Fatigue Mechanism of Welded Eh36 Steel in Simulated Seawater and Under Cathodic Protection

Fabrication, characterization and efficient surface protection mechanism of poly(trans-cinnamaldehyde) electropolymerized coatings for EH36 steel in simulated seawater

Heterogeneous poly( trans -cinnamaldehyde) (PTCA) coatings were electropolymerized on EH36 steel surface in ethanolic electrolyte for corrosion retardation toward the simulated seawater (SSW). The deposited coating was confirmed by morphology observation and wettability. A compact PTCA layer was fabricated with the water content of 0.3% and polymerization time of 600 s. The polymerized mechanism for PTCA was proposed through bonding analysis of coated steel. Open circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopy and surface analyses evidenced the superior protection performance of PTCA-coated steel in SSW for the decreased corrosion current density, increased charge transfer resistance and topography durability. Electrolyte penetration and partial reduction of PTCA during long-term immersion slightly impaired the anti-corrosion efficiency in the aspects of barrier effect and anodic protection. Synergistic analyses of electrochemical frequency modulation clearly distinguished the anodic protection as the dominant factor for the conducting PTCA coating in the long-term protection for steel substrate in SSW.

Crevice corrosion of X80 carbon steel induced by sulfate reducing bacteria in simulated seawater

Crevice corrosion of X80 carbon steel in simulated seawater with the presence of SRB was studied by surface analysis and electrochemical measurements. The electrode inside crevice was seriously corroded. Large amount of corrosion products accumulated along the crevice mouth. Galvanic current densities measurements confirmed that there was a galvanic effect between the carbon steel at the crevice interior and exterior during the crevice corrosion. The difference in the sessile SRB cells quantities and SRB biofilms developments inside and outside crevice caused the galvanic effect between the carbon steel inside and outside the crevice, which further induced crevice corrosion. Increased crevice width reduced the galvanic effect, resulting in less crevice corrosion in wider crevice.

Efficiency of Gemini surfactant containing semi-rigid spacer as microbial corrosion inhibitor for carbon steel in simulated seawater

SRB is one of the main bacteria causing marine microbial corrosion. In order to reduce the loss of microbial corrosion, a Gemini surfactant (12-B-12) containing semi-rigid spacer was used to investigate the anti-bacterial and anti-corrosion performances of carbon steel in simulated seawater by weight-loss test, electrochemical method and surface morphology analysis. The results showed that the inhibition efficiency of 0.01 mM 12-B-12 was as high as 98.3% after 30 days of incubation in simulated seawater with SRB, and the planktonic and sessile SRB on the carbon steel surface can be reduced to undetectable level. Quantum chemical calculation and molecular dynamics simulation were used to study the structure–activity relationship.

Effect of Hydrostatic Pressure on Corrosion Behavior of X70 Steel in Simulated Sea Water

Effect of Hydrostatic Pressure on Corrosion Behavior of X70 Steel in Simulated Sea Water

Corrosion fatigue behavior of Fe-16Mn-0.6C-1.68Al twinning-induced plasticity steel in simulated seawater

The nature of corrosion fatigue of twinning-induced plasticity (TWIP) steel in a simulated seawater environment was investigated through various tests. Results indicated that TWIP steel has high corrosion fatigue susceptibility, which is mainly caused by anodic dissolution at grain boundaries and twin boundaries. However, uniform plastic deformation tends to inhibit corrosion fatigue. The influence of plastic deformation on corrosion fatigue of TWIP steel was clarified through the aspects of microstructure evolution, mechano-electrochemical effect, fatigue damage, etc. Findings reveal that plastic deformation or metallurgical design for high grain boundary strength will improve the resistance of corrosion fatigue for TWIP steel.

Effect of corrosion on the fatigue behaviour of butt welds of G20Mn5QT cast steel and Q345D hot rolled steel in 3.5‐wt% NaCl solution

AbstractCorrosion fatigue experiments are carried out on butt welds of G20Mn5QT cast steel and Q345D hot rolled steel in simulated seawater. The cyclic stress versus number of cycles to failure (S‐N) curve was fitted. The mechanism of crack nucleation at different fracture locations and at different stress levels is analysed. The results show that compared with the S‐N curve of laboratory air, for the S‐N curve of simulated seawater, the number of fatigue failure cycles is significantly reduced when the maximum cyclic stress is less than 190 MPa. At higher stress levels, stress concentrations caused by internal defects near the surface of the weld zone and the heat‐affected zone of G20Mn5QT cast steel cause crack nucleation. At lower stress levels, the main reason for crack nucleation is the stress concentration caused by corrosion pitting. However, there are no obvious internal defects in the heat‐affected zone of the Q345D steel, and corrosion pitting is the main cause of crack nucleation. The stress concentrations caused by pitting lead to crack nucleation.