Corrosive Media Research Articles

Polarization-Accelerated Seawater Splash Simulation for Rapid Evaluation of Protection Performance of an Epoxy Coating on Carbon Steel.

The application of organic coatings is the most cost-effective and common method for metallic equipment toward corrosion, whose anti-corrosion property needs to be improved and evaluated in a short time. To rapidly and rationally assess the anti-corrosion property of organic coatings in the ocean splash zone, a new accelerated test was proposed. In the study, the corrosion protection property of the coating samples was measured by an improved AC-DC-AC test in a simulated seawater of 3.5 wt.% NaCl solution, a simulated ocean splash zone test and a new accelerated test combining the above two tests. The results showed that the corrosion rate of the coating samples was high in the improved AC-DC-AC test, which lost its anti-corrosion property after 24 cycles equal to 96 h. The main rapid failure reason was that the time of the water and corrosive media arriving at the carbon steel substrate under the alternating cathodic and anodic polarization with symmetrical positive and negative electric charges was shortened. The entire impedance of the coating samples was improved by about 1.6 times more than that in the initial early time in the simulated ocean splash zone test, which was caused by the damage effect from the salt spraying, drying, humidifying, salt immersion, high temperature and UVA irradiation being weaker than the enhancement effect from the post-curing process by the UVA irradiation. In the new accelerated test, the samples lost their corrosion resistance after 12 cycles equal to 288 h with the fastest failure rate. On account of the coupling process of the salt spraying, drying, humidifying, salt immersion, high temperature combined with the cathodic and anodic polarization and the UVA irradiation, the penetration and transmission rate of water and corrosive media in the coating were further accelerated, the corrosion rate on the carbon steel substrate was reinforced even larger and the destruction of the top polymer molecules was more serious. The new accelerated test showed the strongest damage-acceleration effect than that in the other two tests.

Superhydrophobic Waterborne Epoxy Composite Coating with Good Mechanical Properties, Icing Resistance, Self-Cleaning Properties, and Corrosion Resistance.

Epoxy resins with higher corrosion resistance typically employ environmentally harmful organic solvents such as xylene, while the corrosion resistance of waterborne epoxy resins, which are relatively environmentally friendly, is not as good as that of oil-based epoxy resins. In this study, by coating the surface of waterborne epoxy resin with a superhydrophobic zinc oxide coating, the corrosion resistance of waterborne epoxy resin was enhanced. During the initial immersion, its impedance value can reach 1010 Ω·cm2. The superhydrophobic nature of the coating itself also ensures the surface's resistance to immersion, delaying the intrusion of corrosive media into the coating. Furthermore, this coating exhibits good mechanical properties, self-cleaning performance, anti-icing performance, and so on. The introduction of superhydrophobic surfaces greatly optimizes the performance of traditional waterborne epoxy resin coatings, opening up directions for the metal anticorrosion field of coatings. Meanwhile, during the EIS testing of the superhydrophobic coating, we observed the occurrence of negative impedance in the results. After studying, we speculated that this phenomenon might be related to the degree of wetting of the superhydrophobic coating. Based on this conjecture, we can evaluate the basic properties of the superhydrophobic coating through this phenomenon.

+Improving the corrosion protection properties of epoxy resin coating by using HKUST-1-BTA@e-Mica two-dimensional nanocomposites

In order to enhance the performance of epoxy coatings to cope with more severe working environments, we develop a convenient energy-saving and fast method to develop an eco-friendly pH-responsive smart coating with long-term corrosion protection. In this paper, HKUST-1 crystals were rapidly synthesised on mica nanosheets (e-Mica) using hydroxyl complex salt (HDS) as an intermediate at room temperature and loaded with the corrosion inhibitor BTA to obtain the composite material HBeM. The use of e-Mica in coatings offers numerous benefits, including extended resistance to corrosive media and the ability to adjust mechanical properties. It is important to note, however, that e-Mica is less compatible with epoxy resin. HKUST-1 can not only be used as a pH-responsive nanocontainer to load a large amount of corrosion inhibitor, but also to regulate the compatibility between mica nanosheets and epoxy resin with a large number of functional groups on HKUST-1. The results of electrochemical impedance spectroscopy showed that HKUST-1-BTA@e-Mica (HBeM) composite enables the coating to provide long-term corrosion protection. The low frequency impedance of the HBeM/EP composite coating, |Z|f=0.01 Hz, was improved by almost three orders of magnitude and remained higher than that of the pure epoxy coating after 30 days of immersion, and the addition of fillers enhances the mechanical properties of the coating. In conclusion, this paper provides a simple, energy-efficient and rapid method for the preparation of smart corrosion-resistant coatings, which has great potential for industrial use.

Water accelerates parabolic oxidation of Pu-Ga alloy: from mechanism to model

The moisture accelerated oxidation can endanger the safety storage of plutonium, but experiments haven’t provided a complete mechanism explanation, let alone a prediction model. Based on first principles calculations, this work reveals the acceleration mechanism of water on Pu-Ga alloy oxidation in moist air and interprets available experimental findings. Specifically, the OH adsorption after H2O dissociation can promote the O-vacancy formation in PuO2 by the polaron interaction mechanism, and then facilitate the vacancy diffusion of the actual corrosion medium O after O2 dissociation. Therefore, the diffusion kinetics of O in Pu-oxide is decisive, which is correlated to the relative humidity (RH) and temperature (T). Based on the micro mechanisms and the available experiments, we propose a method to modify the oxidation kinetic model by taking into account the coupling effects of RH and T, this model provides a new way to evaluate and predicts the acceleration ratio of RH and T on the oxidation kinetics of Pu-Ga alloy. This work comprehensively reveals the acceleration mechanism of moisture and then proposes the oxidation kinetic model, which is significant to the storage and protective of nuclear materials.

Unveiling the anti-corrosion Potential of seaweed macroalga Codium tomentosum: A multifaceted investigation into its mechanisms of copper protection

The seaweed macroalga Codium tomentosum (GAE) was extracted by the maceration method, and it was used as an eco-friendly, nontoxic inhibitor of copper in 1 M H2SO4 corrosion media. To evaluate the composition and protective capacity of the GAE, several methods were employed, gravimetric measurements, electrochemical testing include polarization curves and electrochemical impedance spectroscopy, Fourier infrared spectroscopy, UV–visible spectroscopy, and scanning electron microscopy. The findings indicate the green algae extract successfully prevents copper corrosion when immersed in a corrosive medium. The inhibition efficiency demonstrates an increase with rising inhibitor concentration, reaching its peak at 82 % at concentration of 1 g/L. Operating solely through adsorption and inhibiting active sites on the copper surface, the inhibitor has a mixed inhibition characteristic. Temperature sensitivity is observed, resulting in a decrease in efficiency. The hypothesis of physisorption nature and adherence to the Langmuir isotherm type is supported by the alignment of thermodynamic and kinetic research. In addition, the inhibition mechanism of GAE was studied by quantum chemical calculations and molecular Monte Carlo simulation. This work provides a useful insight into the anti–corrosion of copper during industrial pickling or descaling processes.

PSF@PAO40 microcapsules enhanced epoxy resin coating toward anti-wear/corrosion performance

Microcapsules-enhanced coating emerges as the times require since the traditional organic coating hardly realizes the long-term protection of metal materials. Herein, PSF@PAO40 microcapsules (PPs) were prepared via Poly α-olefin 40 (PAO40) encapsulated within Polysulfone (PSF) shell using solvent evaporation method. Then self-lubricating composite coatings were fabricated by introducing PPs into epoxy resin (EP). The coating structure was characterized using X-ray microtomography (CT), and its relationship with anti-wear/corrosion performance was explored. Compared to pure EP coating, the composite coatings with 10 wt% PPs demonstrated an 87.9 % reduction in friction coefficient and 84.5 % reduction in wear rate. Additionally, the lowest frequency impedance (|Z|0.01 Hz) increased by 1 order of magnitude. Superior anti-wear/corrosion performance of the composite coatings is primarily attributed to the three-dimensional network distribution structure of PPs, which facilitate continuous lubrication and provide a physical barrier against corrosive media.

A device for dynamic testing of the refractory ceramic resistance to biomass ash

The corrosive effects of biomass ash on refractory materials in combustion chambers pose challenges. Development of new castable refractory materials which are more resistant to corrosion requires tests that accurately reflect the conditions occurring in real devices. This article describes the Computational Fluid Dynamics (CFD) design and construction of a device for evaluating the corrosion of refractory materials in dynamic regime. The device allows to simulate combustion chamber conditions accurately, to regulate an injection of corrosive medium on the tested material surface under the specified conditions (temperature, time, and flow). In the present investigation the conventional refractory material was exposed to attack of biomass ash at the temperature of 1300 °C for 3 h to test the functionality of the device. A burner with technology oxygen–enriched combustion was used to heat the device. The corrosion tests were conducted in accordance with the standard P CEN/TS 15,418 and the standard STN EN ISO 21404. The operational state required for corrosion tests at 1300 °C was achieved within 1.12 h. The extent of refractory material degradation in the dynamic corrosion regime was evaluated using electron microscopy-energy dispersive spectroscopy (EM-EDS) and compared with the results of a static crucible test (3 h at 1300 °C). The dynamic test provided sufficient information on the interactions of corrosion medium with the refractories. Its main advantages are the maintenance of non-equilibrium conditions by controlled deposition of the corrosion medium in quantity from 1 to −100 g/h, fast heating rate to operating temperature (20 °C/min), and the possibility of conditions variability during tests (temperature, ox-red. atmosphere, fuel gas flow etc.).

A novel strategy to improve the corrosion resistance of SiCf/SiC composites in high-temperature combustion environments by cooperation of self-healing SiBCN and high-stability Yb2Si2O7

How to improve the resistance to water-oxygen-salt corrosion of SiCf/SiC composites is vital to their long-term service in the advanced aero-engines or gas turbines. SiCf/SiC-SiBCN-Yb2Si2O7 (SSY) self-healing composites were exposed to combustion environments at 1200–1350 °C for a long time up to 100 h. The dissolution of solid Yb2Si2O7 into low-viscosity glassy oxides derived mainly from oxidation of SiBCN leads to the formation of stable Yb2Si2O7-contianing multi-phase silicate which can inhibit the diffusion of corrosive media and alleviate corrosive damage of composites. After corrosion in H2O/O2/Na2SO4 at 1200 °C and 1350 °C, the strength retention rates of SSY are 96 % and 88 %, respectively, (6.4 ± 0.9)% higher than those of SiCf/SiC-SiBCN (SS), due to the good cooperative protective effect of SiBCN-Yb2Si2O7. However, the insufficient dissolution of Yb2Si2O7 causes the formation of plenty of solid/liquid interfaces conductive to the diffusion of corrosive media in H2O/O2 at 1200 °C and 1350 °C. As a result, the retention rates of flexural strengths of SSY are 100 % and 91 %, respectively, (2.5 ± 0.5)% lower than those of SS.

A sensorless centrifugal pump operation states estimation method based on HSSA-BPNN

As a liquid transportation equipment, centrifugal pumps find extensive use in industrial process control. Certain environments involving high temperature, high pressure, and highly corrosive media may not permit the installation of flow and pressure sensors. Consequently, accurately estimating the operating status of centrifugal pumps in the absence of sensors has become a prominent research focus. However, the precision of existing sensorless estimation methods remains a concern. This study introduces a HSSA-BPNN model utilizing valve opening degree, motor rotational speed and shaft power as input variables. A hybrid strategy improved sparrow search algorithm (HSSA) is developed to optimize the back propagation neural network (BPNN). Experimental results demonstrate a low mean absolute percentage error (MAPE) of the test data, which are 2.2741% and 1.6502%, respectively. The absolute errors of flow rate and head are below 0.3 m3/h and 0.5 m, respectively, with relative errors less than 4% and 3%, meeting practical applications.

A methodology to evaluate seawater corrosion on quasi-static tensile properties of a structural steel

With the wind turbine industry growing and increasingly turning its focus to the offshore sector, it is important to grasp the challenges that come with it: the logistic challenges related to transport and maintenance, the exposure to wave and wind action and also the vulnerability to corrosion. The marine environment is a complex and aggressively corrosive environment. The S690 steel, as a structural steel of high mechanical strength, offers weight reduction advantages that are of interest to the sector. However, its behaviour in a corrosive medium is still not well known. As such, this work is part of an effort to characterize S690 steel under marine environment conditions. A methodology for inducing accelerated pre-corrosion on quasi-static tensile specimens of S690 steel, while simulating the environment, has been developed and applied. The effect of this pre-corrosion on the tensile mechanical properties is evaluated through testing in accordance with the ASTM E8 standard. It was found that the induced surface pre-corrosion, equivalent to six months of exposure, did not have a significant effect on the investigated mechanical behaviour.

Effect of electrochemical hydrogen charging in corrosion medium on microstructural evolution and mechanical behavior of an as-forged Ti–6Al–4V (in wt.%) alloy

Effect of electrochemical hydrogen charging in corrosion medium on microstructural evolution and mechanical behavior of an as-forged Ti–6Al–4V (in wt.%) alloy

The impact of oxygen availability on steel corrosion considering the self-balance between anodic and cathodic corrosion cells

An advanced model is developed to elucidate relationship between availability of oxygen and active corrosion, considering the equilibrium between gaseous and dissolved oxygen, as well as the equilibrium of oxygen diffusion and consumption. This research notably incorporates self-regulation mechanisms of cathodes and anodes in both macrocell and microcell corrosion. Accelerated corrosion experiments were performed under simulated marine environment, monitoring variations in corrosive medium concentration and electrochemical corrosion processes. Results indicate significant reduction in oxygen concentration following the activation of rebar. Potential inaccuracies in predicting corrosion rate arise from the adoption of a static cathodic to anodic area ratio was highlighted.

A new facile strategy for addressing the localized corrosion issue at damaged coating via a wind-driven triboelectric nanogenerator

Metal substrate at the damaged coating, exposed directly to the corrosive medium, is susceptible to the localized corrosion, due to the formation of occluded corrosion cells. Herein, a new facile strategy for addressing the localized corrosion issue at damaged coating using a triboelectric nanogenerator (TENG) was proposed. The wind-driven TENG with a simple double-layer structure was designed. The output performance of the TENG can be controlled by adjusting structural parameters and the wind speeds, with the maximum short circuit current, output voltage and corresponding power reaching approximately 102.5 μA, 814 V and 7.6 mW, respectively, at a wind speed of 7.5 m/s. The electrons generated by the TENG can be transferred to the metal substrate at the damaged coating, inducing the cathodic polarization of the metal and providing effective cathodic protection. The reduction reaction, with the consumption of O2 and the formation of OH-, occurs at the metal substrate at the damaged coating. A protective local environment is created by the combination of increased pH and removal of Cl- under the electric field of the TENG. To evaluate the corrosion behavior, immersion experiments and electrochemical measurements were conducted in 3.5 wt% NaCl when the Q235 steels covered the damaged coating were coupled with and without the wind-driven TENG at different wind speeds. Meanwhile, the influence of TENG’s output performance on the cathodic protection effect for the metal substrate at the damaged coating is discussed. This study expands the application of the TENG in the field of corrosion resistance.

Experimental accompanied with computational (atomic/electronic)-level simulation investigations of Polygonum cuspidatum root extract as sustainable corrosion inhibitor for mild steel in aggressive corrosive media.

This study investigates the corrosion inhibition potential of Polygonum cuspidatum root extract (PCRE) on mild steel in a 0.5M HCl acidic environment. Herein, various techniques including electrochemical and gravimetric measurements were employed, along with scanning electron microscopy (SEM) and contact angle (CA) measurements for surface morphology analysis. The impedance study revealed a concentration-dependent enhancement in corrosion resistance, classifying PCRE as a mixed-type inhibitor (i.e., inhibits both anodic and cathodic reactions). The highest efficiency, 96.71% at 298K, was observed at a 1000-ppm PCRE concentration. Langmuir model computations suggested chemisorption and physisorption of PCRE on the electrode substrate. Increased Rp (from 28.648 to 174.01 Ω) and Rct (185.74 Ω cm2) at 1000ppm demonstrated improved corrosion resistance. Additionally, SEM analysis displayed a uniform, protective surface, reducing metal degradation. Theoretical calculations highlighted strong interactions between PCRE and mild steel, with a low energy gap (ΔE), as follows: 1-O-methylemodin (2.267eV) < emodin (2.288eV) < emodin-1-O-glucoside (2.343eV) < piceid (2.931eV) < resveratrol (2.952eV), confirming PCRE's excellent micro-level anti-corrosion capabilities. This eco-benign corrosion inhibitor offers sustainable, low-toxicity protection, cost-effectiveness, and versatile performance, surpassing commercial counterparts while aligning with sustainability goals.

Effect of V2O7 4− anion intercalation on the microstructure and corrosion resistance of MgAl Layered Double Hydroxides films on LA43M Mg-Li alloy

ABSTRACT To improve the corrosion resistance of LA43M alloy, MgAl-NO3 −-Layered Double Hydroxides (LDH) was prepared on the surface of the alloy by an in situ hydrothermal method, and uniform and dense MgAl-V2O7 4−-LDH films were successfully obtained by ion-exchange over different times. SEM, XRD, EDS, electrochemical polarisation, EIS and hydrogen evolution experiments were conducted to analyse microstructure and corrosion resistance of these films. The results verified that with increase of the ion-exchange reaction time, the nanosheets of the MgAl-V2O7 4−-LDH film are larger in size, uniformly distributed, and slightly increased in thickness. The surface of the modified MgAl-V2O7 4−-LDH film grown for 4 h on the surface had a staggered and tilted manner, and the gaps between the nanosheets were small, making it more effective in blocking the corrosive medium. The MgAl-NO3 −-LDH film modified by V2O7 4− anion intercalation can further improve the corrosion resistance of the LA43M alloy.

Study of the corrosion protection effect of the new composition based on gossypol resin in the hydrogen sulfide formation water

We investigated the impact of a new composition (HS-1) composed of gossypol resin and IB-1 reagent taken in the ratio of 3:1 on the corrosion rate in the hydrogen sulfide formation water under laboratory conditions. Concentrations of 20, 40, 60 and 80 mg/l of the new composition were used. The formation water sample taken from well No. 1082 of "Bibiheybatneft" OGPD, SOCAR was used as an corrosion medium. The corrosion effects were also investigated at the concentrations of 50, 100, 150 and 200 mg/l of gossypol resin and 10, 15, 20 and 25 mg/l of IB-1 inhibitor. When the concentration of gossypol resin in the formation water increased by 50–200 mg/l, the corrosion protection effect took a value in the range of 60–82%. When the concentration of IB-1 inhibitor varied between 10–25 mg/l in a hydrogen sulfide medium, the protection effect was between 65–90%. Increasing the concentration of new HS-1 composition in the range of 30–80 mg/l resulted in an increase in its corrosion protection effect between 74–98%. It was found that the optimal consumption rate of gossypol resin, IB-1 inhibitor and HS-1 composition for corrosion protection in an aggressive medium with hydrogen sulfide was 200 mg/l, 25 mg/l and 80 mg/l, respectively.

Influence of riboflavin on the corrosion of X80 pipeline steel by Sulfate reducing bacteria

The sulfate reducing bacteria(SRB) is commonly attached to the surface of buried pipeline steel, and the electron shuttle in the corrosion medium can promote the release of electrons from iron oxidation through the bacterial cell wall into the cytoplasm to accelerate the corrosion of anode iron. This study investigated the impact of riboflavin (RF) as an endogenous electron shuttle on the corrosion behavior of X80 pipeline steel in SRB system. The findings indicated that while the type of corrosion products remains unchanged in samples under SRB+10 mg l−1 RF system, there was an expansion in both area and depth of corrosion pits on the sample surface, resulting in a corrosion loss rate approximately 3 times higher than that observed in SRB system. Furthermore, the polarization resistance (Rp) value of the sample in SRB system is about 2 ∼ 5 times that of the sample in SRB+10 mg l−1 RF system. Additionally, the corrosion current density of X80 pipeline steel samples soaked in SRB and SRB +10 mg l−1 RF system for 14 days is 9.31 × 10-6 A·cm−2 and 1.28 × 10−5 A·cm−2, and the addition of 10 mg l−1 RF increases the corrosion current density of SRB system by about 37.49%. These results indicated that the reaction resistance of SRB-induced MIC in X80 pipeline steel was significantly reduced due to the presence of RF.

INVESTIGATION OF STRUCTURAL AND MECHANICAL PROPERTIES OF TUBING STEELS

The study of the structural and mechanical properties of tubing steels used in wells at oil and gas condensate fields is of particular interest due to the resource intensity of these systems and the high cost of their repair and restoration. Tubing is operated under conditions of increased loads under the influence of its own weight, internal pressure and constant contact with highly aggressive media. As a result of simultaneous exposure to corrosive media and operational loads, tubing is the most consumable downhole material. The destruction and, as a result, the breakage of the tubing suspension occurs as a result of mechanical abrasion and cracking of the pipe body, the development of fatigue cracks in the thread, etc. Contact with aggressive agents of the extracted fluid and reservoir waters leads to various types of corrosion damage: ulcerative, pitting, corrosion fatigue, corrosion cracking, meza corrosion, biocorrosion, etc. Corrosion foci are localized on the inner and outer surfaces of pipes. The problem is complicated by the increased content of carbon dioxide (CO2), hydrogen sulfide (H2S), as well as the presence of various bacteria in oil and gas fields.This article is devoted to the study of the mechanical characteristics and microstructure of tubing steels that were in operation under conditions of complicating factors and highly aggressive corrosive environment. Tubing pipes Ø73x5.5 of strength group E. were tested. The following research methods were carried out: visual inspection; determination of the chemical composition of steel; determination of hardness; uniaxial tensile test; optical microscopy.As a result of the tests, quantitative characteristics of the mechanical properties of the steels were obtained. A significant decrease in the hardness, tensile strength and yield strength of steel has been established under prolonged exposure to complicated operating conditions. Metallographic studies have established the contamination of steels with silicates of various shapes, amounting to 3 and 2 points according to GOST 1778. Microstructural studies have been carried out. The fine-grained ferrite-carbide structure of steels has been revealed. This structure corresponds to the heat treatment mode: quenching followed by tempering.

Effect of Corrosion Media on Biofilm Detachment and the Corrosion Mechanism of Serratia marcescens on Carbon Steel in River Water

Effect of Corrosion Media on Biofilm Detachment and the Corrosion Mechanism of Serratia marcescens on Carbon Steel in River Water

Study the Corrosion Behavior of Low Carbon Steel Weldments Immersed in Tap Water

Corrosion is one of the main sources of failure for metals and alloys, thus it is a major engineering problem. Engineers must consider the corrosion of metals in different environments when designing engineering parts. Metals tend to corrode in different media; they show different behaviors due to differences in chemical composition and the severity of the corrosive medium. In tap water, the corrosion of mild steel products is an electrochemical phenomenon that includes two reactions: the dissolving of iron (anodic) and the reduction of oxygen (cathodic). This work observes the corrosion behavior of welded low-carbon steel by Friction Welding (FW), Shielded Metal Arc Welding (SMAW) , and MIG welding techniques using immersion tests in tap water at different periods. The results revealed that while the corrosion rate of Base Metal (BM) increases, it reaches a nearly steady state in the friction-welded and SMAW-welded samples. The difference in the corrosion rate of the welded samples can be attributed to changes in the concentrations of Cl– and CaCO3 ,as well as the pH values of the corrosive mediums. Pits could be observed in the microstructure of the nugget zone for all weldments.