Corrosion Rate Research Articles

Hybrid Intelligent Model for Predicting Corrosion Rate of Carbon Steel in CO2 Environments

ABSTRACTThis study aims to construct a prediction model for the internal corrosion rate of offshore pipelines in CO2 environments, with the intention of providing effective corrosion prediction and protection strategies for the oil and gas industry. By conducting investigative analysis and integrating CO2 corrosion experimental data, principal component analysis (PCA) was employed to extract the primary influencing factors, which were used as input variables for the support vector regression (SVR) model with corrosion rate as the output variable. The particle swarm optimization (PSO) algorithm was utilized to optimize the hyperparameters of the model, enhancing prediction accuracy. The results indicate that the first eight principal components account for 95.9% of the cumulative contribution, and the optimized SVR model achieved a correlation coefficient (R2) exceeding 0.90. Compared to other models and optimization methods, the SVR model optimized with PCA and PSO effectively predicts the corrosion rate of offshore pipelines, offering theoretical support for corrosion protection.

Insights into the Corrosion Behavior of Pure Magnesium and Magnesium–Calcium Alloy (Mg-1.8 at.% Ca) in Thin-Film and Bulk Forms

This study investigates the microstructural and corrosion properties of pure magnesium (Mg) and Mg-1.8Ca (at.%) alloy in both bulk and thin-film forms. Microstructure investigations showed that the addition of calcium (Ca) to Mg resulted in significant differences in microstructures. The bulk pure Mg exhibited coarse and elongated α-Mg grains, which were refined by Ca addition, together with the formation of a Mg2Ca intermetallic phase distributed throughout the microstructure. In contrast, thin-film Mg-1.8Ca alloys displayed a refined single-phase microstructure with uniform nm-scale grains and no intermetallic formation. The electrochemical corrosion tests revealed that the bulk and thin-film pure Mg exhibited comparable corrosion rates, while a substantial difference between the corrosion resistance of bulk and thin-film Mg-1.8Ca (at.%) alloy was observed. The thin-film Mg-1.8Ca (at.%) alloy showed an exceptionally better corrosion resistance, attributed to the formation of a more stable surface film and the absence of a less noble Mg2Ca intermetallic phase, ensuring a single-phase microstructure. This study highlights the importance of different manufacturing techniques and microstructural control in improving the performance of Mg alloys for high-tech applications.

Biodegradable Mg-1%Ca alloy inhibits the growth of cervical cancer

The traditional treatment for cervical cancer involves aggressive surgery combined with radiotherapy and chemotherapy. Nevertheless, these treatments have certain limitations and side effects, thus breakthroughs and advances are required in cervical cancer therapy. Magnesium alloy is a promising antitumor biomaterial with excellent biocompatibility and biodegradability. However, the potential effects of magnesium alloy on cervical tumors have not been extensively explored. Recent studies have demonstrated that adding a small amount of calcium to the magnesium matrix can reduce grain size and corrosion rate while providing good biocompatibility. We conductedin vivoandin vitroexperiments to test the antitumor properties of Mg-1%Ca alloys. The results indicated that the Mg-1%Ca alloy released Mg2+and OH-more slowly, inhibited the proliferation of SiHa and HeLa cells, induced apoptosis in tumor cells, disrupted the cytoskeleton, and inhibited cell migration and invasion. At the molecular level, Mg-1%Ca alloy significantly activated the mitochondrial apoptosis pathway and inhibited the MAPK/ERK signaling pathway. In the future, Mg-1%Ca may be employed in the treatment of cervical cancer as a novel adjuvant therapeutic material with anticancer function to prevent the occurrence and progression of cancer proliferation and metastasis.

In Situ Repair and Reconstruction of Copper Surface Enhanced Its Anti-Oxidation Properties and Stability for Deep Learning-Powered Anti-Counterfeiting Labels.

The in situ repair of oxidized copper (Cu) surfaces while constructing a superior protective layer is critical for sustainable development and the efficient utilization of metallic materials. Here, a simple solvothermal treatment is presented to repair oxidized Cu surfaces (Cu foils, nanowires, and nanocubes) and reconstruct an antioxidant layer with an ordered (111) crystal-plane (Cu-SC) in situ. Electrochemical measurements reveal that the corrosion rate of Cu-SC in 0.1m NaOH is reduced to 1.99 × 10-3mm yr-¹, a fivefold improvement over pristine Cu (1.00 × 10- 2 mm yr-¹). Density functional theory calculations confirm that the reconstructed (111) surface reduces oxygen molecule adsorption, significantly hinders oxygen atom diffusion into the bulk and continuous adsorption on surface. Anti-counterfeiting labels fabricated from Cu-SC nanowires exhibit exceptional durability, retaining reliable authentication accuracy after 144h at 85°C/85% relative humidity and 2000 bending cycles. The enhanced anti-oxidation properties of Cu-SC ensure the stability of its microstructures, which are critical for deep learning-based authentication, allowing precise feature extraction and accurate label verification even under extreme conditions. These results highlight the potential of (111) surface reconstruction for enhancing material stability, enabling advanced anti-counterfeiting applications, and promoting the sustainable utilization of metallic materials.

Behavior of compounds on the corrosion of ZK61-xCe magnesium alloys

Abstract The corrosion kinetics and the influence of Ce content on the corrosion performance of ZK61-xCe (x=0, 0.5, 1.0, 1.5, wt.%) magnesium alloys in NaCl (0.1mol/L) solution were investigated using hydrogen evolution tests combined with observations of corrosion morphology. The role of compound on the corrosion of the alloy was analyzed based on changes in the microstructure, electrode potentials of compounds and matrix, and electrochemical properties of the corrosion product film. The results show that the corrosion rate of the experimental alloy is faster in the first 3 hours, then the corrosion rate is gradually reduced, and the corrosion process fits the power-exponential dynamics equation. The corrosion rate constants k and exponential n in the corrosion kinetic equations first decrease and then increase with the increase of Ce content, with the Ce content is 0.5wt.%, the alloy has the slowest corrosion rate and the best corrosion resistance. The corrosion rate of the alloy is controlled by the micro-galvanic corrosion. After adding Ce to the ZK61 alloy, the MgZn2 in the alloy is converted to (Mg,Zn)12Ce with more negative electrode potential, and the electrode potential decreases from -0.811V to -1.002V. The electrode potential of the α-Mg matrix in the alloy is about -1.451V, and the potential difference between the compounds and the α-Mg matrix decreases, the corrosion driving force of micro-galvanic corrosion decreases, and the corrosion resistance increases. With the increase of Ce content, the amount of (Mg,Zn)12Ce compounds increases, resulting in an increased number of micro-galvanic couples, increased migration charge density, and decreased corrosion resistance. As the corrosion proceeds, the number of (Mg,Zn)12Ce exposed on the surface of the substrate increases, blocking the contact between the substrate and the corrosion medium, himpeded lateral corrosion propagation and longitudinal corrosion extension of the α-Mg matrix. 

Effect of Si Content on Phase Structure, Microstructure, and Corrosion Resistance of FeCrNiAl0.7Cu0.3Six High-Entropy Alloys in 3.5% NaCl Solution

This study examines the microstructure and corrosion resistance of FeCrNiAl0.7Cu0.3Six (x = 0, 0.1, 0.3, and 0.5) high-entropy alloys (HEAs) in a 3.5% NaCl solution. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and electrochemical testing were employed to systematically analyze the alloys’ microstructures and corrosion behavior. The XRD results indicate that the addition of Si affects the phase structure of the alloy. At Si = 0, the alloy exhibits a single BCC phase. By increasing the Si content to 0.1 and 0.3, a BCC2 phase appears. At Si = 0.5, Si-containing intermetallic compounds form. SEM observations reveal that as the Si content increases, the alloy develops a distinct dendritic structure. Polarization tests in the 3.5% NaCl solution show that the corrosion current density first decreases and then increases with increasing Si content. At Si contents of 0.1, 0.3, and 0.5, the corrosion current densities are 4.275 × 10−6 A·cm−2, 4.841 × 10−7 A·cm−2, and 2.137 × 10−6 A·cm−2, respectively. FeCrNiAl0.7Cu0.3S0.3 HEA exhibits the lowest corrosion current density, indicating a lower corrosion rate. Electrochemical impedance spectroscopy (EIS) tests show that at Si = 0.3, the alloy has the largest capacitive arc radius. The charge-transfer resistance (RCT) for the alloys with the Si contents of 0.1, 0.3, and 0.5 are 2.532 × 105 Ω·cm2, 4.088 × 105 Ω·cm2, 4.484 × 105 Ω·cm2, and 2.083 × 105 Ω·cm2, respectively. FeCrNiAl0.7Cu0.3Si0.3 HEA has the highest RCT, which indicates a more stable passivation film and better resistance to chloride ion intrusion. The corrosion morphology observed after polarization testing shows that all alloys exhibit intergranular corrosion characteristics. The Si content alters the distribution of passivation film-forming elements, Cr and Ni. Compared to other alloys, the corrosion morphology of FeCrNiAl0.7Cu0.3Si0.3 HEA is more complete. Combining the polarization, EIS, and corrosion morphology results, it can be concluded that FeCrNiAl0.7Cu0.3Si0.3 HEA exhibits the best corrosion resistance in the 3.5% NaCl solution.

Effect of Mn content on the corrosion behavior and biocompatibility of biodegradable Zn-Mn alloys

Zinc-based alloys have attracted increasing attention as biodegradable metals by virtue of their excellent mechanical, degradable and biocompatible properties. By introducing different levels of manganese (0.1, 0.3, 0.5 and 0.8 wt%), the properties of pure zinc were improved. The obtained zinc-manganese alloys consisted mainly of a zinc matrix and a MnZn13 phase, which led to a significant improvement of the mechanical properties with ultimate tensile strength (UTS), yield strength (YS) and elongation up to 117.3 MPa, 110.4 MPa, and 14%, respectively, and a Vickers hardness of 78 HV. After immersion in simulated body fluid (SBF), the addition of manganese slightly slowed down the corrosion rate of pure zinc, with an average corrosion rate of approximately 0.12 mm/y. Subsequent electrochemical tests and scanning Kelvin probe tests further confirmed this observation. In addition, the zinc-manganese alloys showed better resistance to E. coli and Staphylococcus aureus than pure zinc according to antimicrobial and in vitro cytotoxicity tests. Cell viability in the alloy extraction solution was higher than that of pure zinc and remained within acceptable limits (> 75%). In summary, Zn-Mn alloy has excellent performance, the promoting effect of Mn element on osteogenesis, and the excellent mechanical properties of the alloy itself, making it a potential biodegradable material for orthopedics.

Negative mixing enthalpy medium-entropy Ti-Zr-Nb-Al alloys with ultrahigh elastic admissible strain, strength-elongation product, and biocompatibility for bone implant applications.

Negative mixing enthalpy medium-entropy Ti-Zr-Nb-Al alloys with ultrahigh elastic admissible strain, strength-elongation product, and biocompatibility for bone implant applications.

A Comprehensive Assessment of Dissolved Oxygen Fluctuations and Biocorrosion Trends in the Sea of Marmara

Izmit Bay (IZ17) and Cınarcık Basin (45C) are the important points where low dissolved oxygen (DO) is observed in the Sea of Marmara. Investigating oxygen levels is essential regarding the sustainability of marine environments and evaluating possible microbiologically influenced corrosion (MIC) risks. Sulfate-reducing bacteria (SRB) play a pivotal role in the biogeochemical cycle, and they are the most aggressive group for MIC. In this study, suboxic and anoxic conditions in the Sea of Marmara were evaluated for the first time with SRB and other heterotrophic bacteria. The physicochemical parameters of seawater, nutrient analysis, hydrogen sulfide (H2S), and sulfate measurements were performed. Total SRB and aerobic heterotrophic bacteria (AHB) cells were determined along the water column. Also, the MIC tests were performed. Results showed that the corrosion rate of Al7075 alloy was increased by SRB biofilm in real seawater. Also, suboxic conditions were observed in the bottom waters of IZ17 and 45C stations and the transition zone from suboxic to anoxic conditions at deeper depths was detected in IZ17. It indicated that the suboxic and anoxic conditions exhibit a variable profile in the Sea of Marmara. This study highlights the supportive role of examining microorganisms to better understand the biogeochemical cycles.

Study on the Corrosion Resistance Mechanism of Nitric Acid Passivation on 316L and SUS329J3L Duplex Stainless Steels in a Denitrification Agent.

316L and DSS 2205 suffer from pitting corrosion in a denitrification agent, NaClO2 solution, despite their excellent corrosion resistance and widespread utilization in plants. Herein, nitric acid passivation was successfully employed to enhance the corrosion resistance of 316L and DSS 2205 in 3% NaClO2 solution. The 3% NaClO2 solution, in which 316L and DSS showed the lowest corrosion rate, was chosen by electrochemically studying the effect of NaClO2 concentration on the steel's corrosion from a series of solutions containing 1%, 3%, 6%, and 10% NaClO2. The passive films with and without nitric passivation were investigated by chemical composition, electrochemical property, semiconductor behavior, and morphology observation analyses. The enhanced corrosion resistance of both 316L and DSS 2205 after nitric passivation was attributed to the Cr enrichment and decreased active area on the steel surface. The semiconductor property test and point defect model showed that both the reduced doping density and the decreased diffusivity contributed better resistance against ClO2- and Cl-. The passivated 316L showed better corrosion resistance according to electrochemical tests and potentially is an option to replace high-cost DSS 2205.

Effect of diffusion in the model tissue on biocorrosion of Mg alloys.

Effect of diffusion in the model tissue on biocorrosion of Mg alloys.

Effect of MICP on reinforcement corrosion of cement concrete exposed to the marine environment

Reinforcement corrosion in marine environments poses a significant threat to the durability of concrete structures. This study investigates the effects of microbial-induced carbonation precipitation on reinforcement corrosion of concrete exposed to the marine environment. The investigation involved a comprehensive evaluation of the mechanical properties, chloride penetration, corrosion performance, self-healing ability, and microstructural analysis of concrete samples treated with microbial-induced carbonate precipitation (MICP) exposed to seawater (SW) and sodium chloride (NaCl) solutions. The study was conducted through compressive, flexural strength, and chloride concentration tests, self-healing cracks analysis, linear polarisation LPR, scanning electron microscopy (SEM), and X-ray diffraction. The experiments used an environmentally friendly, broad-spectrum bacteria, Bacillus subtilis, to perform MICP. The results revealed that Bacillus subtilis through MICP had a negative impact on mechanical strength; after 28d, the compressive strength decreased up to 49.22% and 51.04% for 6% and 2% Bacillus subtilis dosage, respectively. Bacterial concrete had a higher chloride concentration than the concrete without bacteria; an increase of up to 123.28% was observed in 4% bacterial replacement at 84 days of curing. MICP-concrete samples immersed in seawater and sodium chloride solutions showed no healing capability. During the exposure setup for 98 days, LPR decreased over time, indicating an increase in corrosion rate.

Corrosion analysis of stainless steel exposed to Karanja oil biodiesel: a comparative study with commercial diesel fuel, surface morphology analysis, and long-term immersion effects in alternative fuels

Abstract The ever-growing energy demand necessitates the deployment of renewable alternatives as fossil fuel reserves diminish. The biodiesel generated from these non-edible feedstocks, such as Karanja, and Jatropha oils, offers an environmental alternative without affecting food security. Transesterification process (using methanol as solvent and sodium hydroxide (NaOH) catalyst) was used to prepare biodiesel. The stainless steel, mild steel, and cast iron materials were immersed in Karanja oil biodiesel blends (B80 and B90) and commercial diesel for 1872 h at 37 °C to critically examine the corrosion behavior with their comparison analysis. It was unveiled that biodiesel is more prone to corrosion than diesel fuel under comparable identical conditions. The corrosion rates determined by weight loss measurements in biodiesel were found to range from 0.0173 mm/year to 0.0194 mm/year for stainless steel, 0.03076 mm/year to 0.03232 mm/year for mild steel, and from 0.0505 mm/year to 0.0528 mm/year for cast iron, as compared to 0.009 mm/year for stainless steel, 0.015 mm/year for mild steel, and 0.017 mm/year respectively for cast iron in diesel. The intense severe melting of biodiesel as compared to diesel samples can be determined by employing the SEM analysis at 200X and 400X magnification scales. Hence, this study has underscored the significance of selecting the appropriate corrosion resistant materials that are suitable for the continued prolonged storage and utilization or application biodiesel.

Evaluating of indium corrosion in sodium borate solutions: a Taguchi method approach

The oxide film formed on an indium electrode immersed in a sodium borate (Na2B4O7) solution is influenced by the solution’s concentration, pH, and temperature, as revealed by open-circuit potential (OCP) and polarization techniques. The rate of oxide film growth decreases with increasing pH and rising solution temperature. In this study, we employed Taguchi’s design of experiments (DOE) to minimize the number of experimental trials while identifying the optimal conditions for reducing indium corrosion. The primary objective was to lower the corrosion rate (CR) by optimizing process parameters using the “smaller is better” approach for the signal-to-noise (S/N) ratio. This optimization was based on CR values derived from OCP and potentiodynamic polarization data. An L25 (5³) orthogonal array (OA) was used to evaluate three key factors: Na2B4O7 concentration, pH, and solution temperature. The optimal factor combination was determined to be (A1 B2 C1), corresponding to a Na2B4O7 concentration of 0.100 ± 0.05 mol/L, a pH of 10.51 ± 0.002, and a solution temperature of 15 ± 0.4 °C. These conditions were identified as the most effective for minimizing CR of indium under the studied conditions.

Performance of Salak <i>(Salacca zalacca)</i> Seed Extract to Green Corrosion Inhibitor on AISI 1040 Steel

This study aimed to determine the effect of concentration and immersion time of Salak (Salacca zalacca) Seed extract as a green inhibitor on the corrosion inhibition efficiency and corrosion rate of AISI 1040 steel in a 1M HCl environment. The chemical composition of AISI 1040 steel was confirmed using OES testing to verify its compliance with AISI 1040 chemical standards. The antioxidant activity of the salak (Salacca zalacca) seed extract was determined through the 1,1-Diphenyl-2-Picrylhydrazyl (DPPH) test yielding an IC50 value of 192.55 ppm, indicating weak antioxidant activity. Qualitative phytochemical analysis confirmed the presence of flavonoids and tannins in the extract, as verified by Fourier Transform Infrared (FTIR) testing. The study explored concentration variations ranging from 100 to 500 ppm and immersion time variations of 10 to 30 days were used. The highest inhibition efficiency was obtained at 500 ppm concentration, while the lowest was at 100 ppm, with values of 40.26% and 18.90% respectively. Additionally, the corrosion rate was reduced to 0.035 mm/year at the highest concentration of 500 ppm. These findings demonstrated the potential of salak (Salacca zalacca) seed extract as an eco-friendly, effective corrosion inhibitor for AISI 1040 steel.

Investigation on the Corrosion Behavior of Reinforced Recycled Aluminium Cans by Leadwood Particles

Corrosion refers to the deterioration of both metal and non-metal objects caused by their electrochemical reactions with the environment around them. The objective of this study work is to investigate the corrosion characteristics of Aluminium that has been strengthened with leadwood particles. Aluminium and organic leadwood particles were combined through the process of smelting and stir-casting, using various weight ratios. Linear politization method was used to determine the corrosion rate. Taffel plots were used to determine the polarization potential and the corrosion current. The results indicated that Leadwood can be successfully used to reinforce and enhance the corrosion resistance of Aluminium. 2% leadwood reinforced sample was corroding at a rate of 1.3366mm/yr, an improvement of 37.5% to the parent Aluminium sample (2.1416mm/yr), while the 3% pulverized leadwood reinforce sample’s corrosion rate was 1.9053mm/yr (10.9% corrosion improvement).

Promising Organic Inhibitor of Salak <i>(Salacca zalacca) </i>Peel Extract on AISI 1040

This study investigates the corrosion inhibition properties of Salak (Salacca zalacca) peel extract as a green inhibitor on AISI 1040 steel in a 1M HCl acidic environment and focusing on secondary metabolites such as flavonoids and tannins. The qualitative phytochemical analysis showed antioxidant activity of the inhibitor extract was categorized as moderate with an IC50 value of 105.219 ppm. Functional group analysis using FTIR indicated that the flavonoids and tannins in the extract acted as antioxidants and inhibited corrosion growth. The weight loss test revealed the highest inhibition efficiency 11.13% was achieved at a concentration of 200 ppm after 20 days of immersion. In the potentiodynamic polarization test, the corrosion rate was 0.025 mm/year at the same concentration and immersion time. These results suggest that Salak (Salacca zalacca) peel extract can effectively inhibit corrosion at spesific concentrations but its efficiency diminishes at higher concentrations.

Inhibition Mechanism of Corrosion of Aluminium Alloy in Ordinary Portland Cement Paste by Polyaluminium Sulphate

The expansion, cracking and deterioration of properties during utilisation and solidification of municipal solid waste incineration bottom ash are key problems that are caused by the reaction of metallic aluminium in the bottom ash in the highly alkaline environment of hardened Portland cement. In this study, polyaluminium sulphate (PAS) was introduced into ordinary Portland cement (OPC) to inhibit the corrosion of aluminium alloy. The results indicate that PAS successfully inhibited the corrosion of Al in hardened OPC paste, prevented the expansion and cracking, reduced the amount of hydrogen gas release and formed a thinner and dense corrosion layer on the Al plate surface. The mechanism of corrosion inhibition of Al by PAS was the increase of initial Al(OH)4− concentration by hydrolysis, which expanded the pH range of passivation and transformed the porous loose bayerite layer to a dense homogeneous one around the Al plate without modification of the corrosion product (bayerite). The corrosion rate of the Al alloy in hardened OPC paste was reduced by 213 times by the addition of PAS, from 288.30 mm a−1 without PAS addition to 1.35 mm a−1 with PAS addition. This study casts light on the effective inhibition of corrosion of the Al alloy in OPC.

Effect of Surface Finish on CO2 Corrosion of Low-Alloy Steel in Simulated Sea Water and Well Environments

The study investigates the influence of surface finish on corrosion of a grade API L80 low-alloy steel. Samples of this steel with different surface finishes produced by rough mechanical grinding (RG sample) or by finer polishing (FP sample) have been studied after exposure to corrosive environments. It is found that the dissolution rate is one to two orders of magnitude higher for the RG sample with a rougher surface than for the FP samples with a smoother surface. Scanning electrochemical microscopy shows selective corrosion of the RG sample, while the FP sample undergoes slow uniform corrosion, followed by localized corrosion after long exposure. A detailed analysis of the corrosion process indicates that in a simulated well environment containing Fe2+ and Ca2+ ions, fast precipitation of CaCO3 on the rougher surface initially reduces the corrosion rate. However, once a protective scale starts forming on the surface, the effect of surface finish on corrosion resistance becomes less significant. The scale morphology and phase composition vary between the samples with the different surface finishes.

Effect of High Potential on Carbon Corrosion of Cathode Catalyst Layer in Proton Exchange Membrane Fuel Cells

Abstract The degradation of the catalyst layer is the main reason for the performance reduction of the proton exchange membrane fuel cells. The effects of high potential holding time, cell temperature, and relative humidity (RH) on carbon corrosion of cathode catalyst layer are studied in the present paper. The fuel cell was maintained at 1.4 V under three conditions (80°C and 100% RH, 60°C and 100% RH, 80°C and 40% RH) and at different durations. The carbon corrosion rate was faster under high temperature and high RH. After high-potential holding test, the membrane electrode assembly (MEA) showed a decrease in performance, electrochemical active surface area (ECSA), and proton conduction resistance within the catalyst layer, as well as an increase in charge transfer resistance. After maintaining 1.4 V for 180 min, the ECSA retention rate of MEAs are only about 30%. The changes in the ECSA and the proton conduction impedance precede the performance degradation, which could more quickly reflect the degradation of carbon materials. Furthermore, this work investigated the evolution process of carbon corrosion under high potential based on duration and proposed a three-stage degradation mechanism of the cathode catalyst layer.