The use of electronics in many climates and high- and low-voltage applications elevates the propensity for humidity-driven failure mechanisms like leak current (LC) and electrochemical migration due to water film formation on printed circuit board assembly (PCBA) surfaces. Therefore, optimizing creepage in critical areas of PCBA layouts is critical to mitigate high-voltage-related issues. This study combines two types of simulations providing a predictive methodology simulating effects of different layout designs and parameters like water film electrolyte properties and voltage levels. The first uses ‘secondary current distribution’ physics in COMSOL on a three-dimensional two-electrode PCB layout with multi-parameter variability (water layer thickness, conductivity, electrode dimensions, pitch distance and supply voltage), outputting LC data. Physical testing using test PCBs serves as validation. The second is numerical simulation using the multivariate adaptive regression splines (MARS) algorithm. LC data from COMSOL trains the MARS model to understand parametric interactions. A correction factor derived from comparing COMSOL and physical test data corrects the MARS model, creating an ML model connecting PCBA design parameters with water film characteristics.
Marine Cu-Ni alloys suffer sulfide and flow-induced corrosion, and fluctuating nickel prices drive the demand for nickel-free alternatives. Despite good mechanical properties, the seawater corrosion behaviour of nanocrystalline Cu–Ta alloys remains unclear. This work computationally explores 0–20 at% Ta Cu–Ta alloys and reveals a dual anti-corrosion mechanism. Ta 2 O 5 -coated nanoparticles significantly inhibit oxygen reduction via cathodic blocking. Compared with Cu 2 O films (0.41 V passivity margin), Ta 2 O 5 offers superior seawater stability with a 1.63 V margin. High-throughput screening determines the optimal composition (5–13 at% Ta) and microstructure (3–10 nm particles). The optimized Cu–Ta alloys exhibit a corrosion rate of 0.015–0.025 mm·y −1 , comparable to commercial Cu–10Ni alloys while avoiding nickel-related drawbacks. Grain boundary enrichment and oxygen reduction current density ratio dominate corrosion performance. The preliminarily identified cathodic feature of Cu–Ta galvanic coupling needs experimental validation. This method enables efficient corrosion screening for immiscible alloys.
This study investigated the influence of sizing materials on the corrosion resistance of basalt fibers exposed to 16 controlled environments combining pH 4–13 and salinity from 0 to 20,000 ppm as chloride. Fibers were exposed to 60°C for 600 days in an environmental chamber, and degradation mechanisms were evaluated using SEM-EDX (scanning electron microscopy and energy-dispersive X-ray spectroscopy) analysis and chemical analysis of exposure solutions. Sized fibers consistently exhibited less degradation than unsized fibers due to the protective sizing layer. Fiber deterioration intensified under highly alkaline and saline conditions, with seawater causing the most damage because of the combined effects of chloride and sulphate ions. Sulphate, together with multivalent cations (Mg 2+ , Ca 2+ , Fe 2+ , Al 3+ ), promoted thicker corrosive layers via insoluble precipitates (e.g., gypsum) and adsorption on Fe-Al hydroxide crusts. Solution chemistry indicated leaching of Al, Ca, Fe and K from the fibers, while Mg and Na showed inverse trends. Hydroxide and chloride attack on the silica network further accelerated deterioration. Although the sizing layer gradually dissolved through salt precipitation and organic leaching, it provided measurable early-stage protection in aggressive environments which emphasised the need for more durable coatings to ensure long-term performance in harsh marine and alkaline environments.
Southwestern China features a subtropical monsoon humid climate that induces severe corrosion of railway infrastructure, yet long-term field data and systematic material evaluation for railway steels remain scarce in this region. This work established a multi-method validation system integrating 365-day field online monitoring, 365-day natural exposure, and 96- h indoor accelerated cyclic immersion testing, to systematically investigate the atmospheric corrosion behaviour of U71Mn, U75 V, and Q500NH steels in the subtropical humid climate of China. The three steels exhibit distinct seasonal fluctuations in corrosion rate. Their annual average corrosion rates measured by online monitoring and 12-month natural exposure test are 5.13–6.00 μm/a and 6.36–8.55 μm/a, respectively, both classified as mild–moderate corrosion. Q500NH weathering steel exhibits a 23%–25.6% lower corrosion rate than the two rail steels, and temperature is identified as the dominant environmental factor. This study provides field-based data support and engineering guidance for material selection and corrosion protection of railway infrastructure in subtropical humid regions.
This study investigates pH-driven mechanistic transitions in the pitting corrosion of selective laser melted (SLMed) AlSi10Mg alloy in 3.5 wt.% NaCl solution at pH 2, 6, and 12. The alloy was produced by laser powder bed fusion and examined using SEM/EDS and XRD before and after electrochemical exposure. Corrosion performance was evaluated using OCP, PDP, CPP, EIS, and CA. The electrochemical response followed the order pH 6 > pH 2 > pH 12. At pH 6, the alloy showed the most noble E corr (−754.4 mV), the lowest i corr (5.97 µA cm −2 ), and the lowest corrosion rate (0.065 mm year −1 ), indicating the highest passive-film stability. Acidic chloride solution (pH 2) increased i corr to 27.78 µA cm −2 and the corrosion rate to 0.303 mm year −1 because of chloride-assisted oxide dissolution and metastable pit activity. In contrast, alkaline exposure (pH 12) produced the most active E corr (−1062 mV), i corr of 7.45 µA cm −2 , and severe surface activation due to hydroxide-driven amphoteric dissolution through soluble aluminate formation. CPP analysis further confirmed pH-dependent pit stability, with narrower hysteresis at pH 6 and delayed repassivation under alkaline conditions. EIS showed the highest interfacial resistance at pH 6 and the weakest passive-film protection at pH 12.
Understanding the impact of elevated temperatures on chloride-induced corrosion of reinforcing steel is critical for assessing the long-term durability of concrete structures in hot climates. In this study, concrete prisms reinforced with carbon–manganese steel rebars and cast with varying chloride concentrations were exposed to four temperatures (20 °C, 35 °C, 50 °C and 65 °C) for a period of 730 days. The results revealed a substantial increase in corrosion rates at temperatures above 50 °C. Detailed analysis of the corrosion products provided key insights into the mechanisms driving this accelerated degradation. X-ray diffraction analysis revealed that the akaganeite phase (β-FeOOH), present in corrosion products at lower exposure temperatures (20 °C, 35 °C and 50 °C), was absent at 65 °C. This disappearance is attributed to the transformation of akaganeite into the lepidocrocite phase (γ-FeOOH), which is believed to promote the corrosion process. Scanning electron microscopy examination further indicated exfoliation of the corrosion product layer formed at 65 °C, suggesting a breakdown in the protective barrier and an increased vulnerability to corrosion. These findings highlight the detrimental synergy between high temperature and chloride ingress on rebar corrosion in concrete structures.
This study reports the fabrication and evaluation of an innovative anti-corrosive agent composed of ternary nanoparticles of metals like iron (Fe), zinc (Zn), and cerium (Ce) into a copolymer matrix of oxy-carboxymethylated chitosan-graft-polyaniline (O-CMCs-g-PANi) for corrosion inhibition of carbon steel in acidic conditions. Four nanostructures, FeNPs@O-CMCs-g-PANi, ZnNPs@O-CMCs-g-PANi, CeNPs@O-CMCs-g-PANi, and Fe/Zn/CeNPs@O-CMCs were prepared through the carboxymethylation of chitosan, followed by graft polymerization of polyaniline and subsequent incorporation of Fe, Zn, and Ce nanoparticles. Characterization of the prepared nanocomposites was conducted through Fourier transform infrared spectroscopy, scanning electron microscopy paired with energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, selected area electron diffraction, and Brunauer–Emmett–Teller methods, showing that there was effective functionalization of the polymer network and uniform distribution of the metallic nanoparticles. As the concentration of the inhibitors increased, the corrosion inhibition efficiency increased to achieve values of 88.1%, 93.1%, and 98.6% at 200 ppm for ZnNPs@O-CMCs-g-PANi, CeNPs@O-CMCs-g-PANi, and Fe/Zn/CeNPs@O-CMCs-g-PANi, respectively. The electrochemical studies revealed that the ternary nanocomposite had better anti-corrosion properties than the mono-metal and bimetal systems. This is because the synergistic effect of Fe, Zn, and Ce oxides leads to a higher specific surface area and adsorption capability. In addition, the interfacial stability is increased, which gives rise to the formation of a protective film layer on the steel surface. Furthermore, the calculated standard free energy of adsorption values were more negative than −40 kJ mol −1 , indicating that corrosion inhibition predominantly occurs through chemisorption. These findings demonstrate that Fe/Zn/CeNPs@O-CMCs-g-PANi is a highly efficient and sustainable nanocomposite inhibitor with excellent potential for protecting carbon steel in aggressive acidic environments.
This review focuses on the advancements in eco-friendly corrosion inhibitors derived from biomass-mediated nanoparticles, specifically aimed at mitigating mild steel corrosion in acidic environments. It provides insight into where bio-wastes come from, how they are collected, their environmental benefits, how they compare to semi-synthetic inhibitors, and how well they work in corrosive conditions. Along with inhibitory methods like adsorption and the creation of protective layers, the use of nanotechnology to make inhibitors work better is also being looked into. Evaluation techniques such as spectroscopic analyses (Fourier transform infrared spectroscopy, UV-vis spectroscopy), surface analysis (scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy), electrochemical methods (e.g., Electrochemical impedance spectroscopy, potentiodynamic polarisation), gravimetric measurements and adsorption isotherms are summarised to show how they work to test inhibitor performance. For mechanistic insights, computational techniques like density functional theory and molecular dynamics simulations have been added. The review also discusses microbiologically influenced corrosion (MIC) and suggests novel remedies, including biosurfactants and bio-nanohybrids. Its unique synthesis of biomass wastes as scalable, environmentally friendly substitutes for traditional inhibitors makes a significant contribution by connecting lab results with real-world issues such as thermal stability and MIC and promoting hybrid nanomaterials for improved, long-lasting corrosion protection.
Hydrogen embrittlement remains a critical damage mechanism for structural materials commonly used in oil and gas pipeline and well, particularly under H 2 S-containing sour conditions. Nickel coatings can enhance corrosion resistance for structural carbon steels avoiding the selection of corrosion resistant alloys. In this study, Ni-based composite coatings containing silicon carbide (SiC) and multi-walled carbon nanotubes (MWCNT-COOH) were co-electrodeposited to improve hydrogen barrier performance by limiting hydrogen ingress. The influence of deposition current density on microstructure and hydrogen permeation was investigated under identical deposition time and charging conditions. Hydrogen permeation was assessed using the Devanathan–Stachurski cell as a comparative electrochemical method relevant to aqueous H 2 S-related environments. Results indicate that the composite coating deposited at 5 A/dm 2 exhibited the most compact and homogeneous morphology, with well-dispersed SiC and MWCNT-COOH within the nickel matrix. The modified microstructure was associated with reduced surface defects and lowered hydrogen permeation. Compared to conventional nickel coating, the composite coating achieved a 75% reduction in effective hydrogen permeation coefficient, demonstrating that hydrogen permeation resistance is governed by microstructure-controlled transport rather than coating thickness alone. These findings highlight the potential of Ni-based composite coatings as hydrogen barrier layers for oil and gas pipeline steels in sour environments.
Repurposing natural gas pipelines for hydrogen transport is a cost-efficient strategy to accelerate the hydrogen economy. However, beyond the well-established risk of hydrogen embrittlement, hydrogen permeation may increase the intrinsic corrosion susceptibility of steel and create subsurface conditions that favour microbiologically influenced corrosion by enriching hydrogen-utilising microbial communities along buried pipelines. We exposed hydrogen-charged steel in a soil-inoculated medium containing a field-relevant microbial community and observed severe corrosion. The combined effects of hydrogen effusing and microbial activity led to excessive rust, carbonate, and carbonaceous compounds, intensifying localised attack. Pronounced microbial shifts were observed in response to hydrogen-charged specimens, favouring hydrogen-metabolising bacteria, indicating that hydrogen permeation stimulates metabolic activity and corrosion, revealing a corrosion mechanism currently overlooked in pipeline risk assessments.
Internal localized corrosion of carbon steel pipelines severely threatens the service safety of oil and gas transportation facilities in CO 2 -containing aqueous environments. In this work, the corrosion evolution and localized corrosion initiation mechanisms of carbon steel in CO 2 –Cl − –HCO 3 − coexisting environments were systematically investigated under varying temperatures and HCO 3 − concentrations. The results demonstrate that the initiation of localized corrosion is primarily attributed to the formation of loose and porous FeCO 3 films, which fail to block the permeation of aggressive Cl − and expose the steel substrate to continuous corrosion. In contrast, the synergistic effect of elevated temperature and appropriate HCO 3 − concentration significantly improves FeCO 3 supersaturation and promotes the formation of dense, uniform, and protective FeCO 3 films, which effectively isolate the substrate from corrosive media and inhibit localized corrosion. Furthermore, this study quantitatively clarifies the optimal matching relationship between temperature and HCO 3 − concentration for the growth of high-quality protective FeCO 3 films. The findings provide fundamental mechanistic insights and practical guidance for the targeted regulation of HCO 3 − to mitigate localized corrosion of carbon steel in CO 2 -saturated oil and gas production systems.
This study comparatively evaluates the corrosion behaviour of binary magnesium–titanium (MgTi) and aluminium–vanadium (AlV) alloys recovered from automotive scrap in dilute H 2 SO 4 (0.000625–0.1 M), NaCl (0.5–4.5 wt%) and mixed H 2 SO 4 /NaCl environments. Corrosion performance was assessed using gravimetric weight-loss, potentiodynamic and cyclic polarisation, open-circuit potential monitoring, electrochemical impedance spectroscopy (EIS) and post-exposure optical microscopy. AlV alloy exhibited markedly superior corrosion resistance in all tested media, forming a compact, self-healing oxide film that conferred high polarisation resistance and partial passivation capability. In contrast, MgTi alloy underwent rapid active dissolution, displaying very high corrosion rates, low impedance, unstable open-circuit potentials and severe surface degradation dominated by pitting and general attack. The presence of vanadium in the aluminium matrix was responsible for the stable passive layer, whereas the MgTi system formed only porous and non-protective corrosion products. The results demonstrate that, among the two lightweight binary alloys examined, AlV possesses significantly greater resistance to acidic, chloride-containing and mixed corrosive environments, making it considerably more suitable for structural applications where exposure to de-icing salts, acidic condensation or marine atmospheres is anticipated. MgTi, however, requires additional protective measures (coatings, inhibitors or further alloying) for practical use in aggressive service conditions.
In recent years, computer technology has advanced to the point that cellular automata models are widely used in corrosion research. Cellular automata models can simulate the spatial–temporal evolution of complex systems using simple local rules and are useful for describing micro-mechanisms and macro-phenomena in corrosion processes. This paper first describes the usefulness of cellular automata models in corrosion simulation and then organises a general framework for constructing corrosion-based cellular automata. Then, it analyses research hot spots, technology development and challenges, as well as future development trends in cellular automata simulation of corrosion. Cellular automata models have achieved remarkable results in simulating various corrosion types, including uniform corrosion, pitting corrosion, intergranular corrosion and fatigue corrosion. They have also been widely adopted in materials science, engineering and biomedicine. However, challenges remain in multiphysics field coupling, model validation, parameter optimisation and integration with other simulation methods. Future trends of cellular automata models will focus on multidisciplinary collaboration, close integration of experiments and simulations, integration of real-time monitoring technology and expansion of application scenarios. This will improve model accuracy and practicality and provide theoretical and technical support for solving and controlling corrosion problems.
The low-temperature toughness and corrosion resistance of a novel weathering bridge steel were investigated through low-temperature Charpy impact tests and salt spray corrosion experiments. It was demonstrated that the experimental steel exhibits exceptional ultra-low-temperature toughness, achieving a maximum impact absorption energy of 53 J at −196 °C. The superior low-temperature performance originates from its refined grain structure, high proportion of high-angle grain boundaries, granular bainite microstructure with packet boundaries, and uniform dislocation distribution induced by recrystallization behavior. The enhanced corrosion resistance of the tested steel mainly arises from the cooperative interaction among Cu, Ni, and Mo. Mechanistically, CuFeO 2 and NiFe 2 O 4 phases absorb Mo oxides, generating a composite protective film that stabilizes within the corrosion product layer. This unique mechanism enhances the rust layer's compactness, reduces electrochemical activity, modifies the ion-selective permeability of the oxide layer and mitigate the pitting corrosion behavior.
In carbon capture utilisation and storage systems, impurities in captured CO 2 streams can strongly alter corrosion behaviour, yet their interactive mechanisms remain poorly understood. This study investigated the corrosion behaviour of API L80-1Cr carbon steel under impurities – H 2 S, SO 2 and HNO 3 present in aqueous CO 2 in simulated conditions relevant to carbon capture utilisation and storage systems but at ambient pressure and temperatures of 5 °C and 30 °C. The individual and combined effects of these impurities on corrosion rates of carbon steel and its morphology were examined by using potentiodynamic polarisation, linear polarisation resistance, scanning electron microscopy and X-ray diffraction. The results showed key novel findings: (i) corrosion in HNO 3 environments that proceeds by pit initiation followed by pseudo-passivation, and (ii) antagonistic effects in multi-impurity systems, where simultaneous presence of H 2 S, SO 2 and HNO 3 produces corrosion rates comparable to or lower than HNO 3 alone, contradicting the prevailing assumption of additive aggressiveness. (iii) Sequential impurity exposure further revealed that H 2 S can stabilise surfaces pre-corroded by HNO 3 through the formation of protective sulphide layers, while SO 2 consistently destabilises both sulphide and nitrate modified surfaces. Collectively, these findings provide essential mechanistic insights, refine the understanding of impurity interactions in CO 2 transport environments and highlight the importance of considering impurity interplay, not only single-species effects, in the design of resilient carbon capture utilisation and storage infrastructure.
This study investigates recurrent leakage failures that occurred at nearly identical locations in 1Cr18Ni9Ti stainless steel pipes from multiple aircraft. Surface analyses reveal characteristic damage features: an inner-surface 'valley' with honeycomb-like craters and facets, contrasting with a single outer-surface perforation. The failure process involves progressive pit initiation, followed by the nucleation and multidirectional growth of fatigue cracks. Cavitation erosion is identified as the primary failure mode, whereby cumulative bubble collapse progressively reduces wall thickness. Simulations using AMESim and oil-gas two-phase flow models demonstrate that a sudden pressure drop creates low-pressure regions and promotes gas accumulation on the inner side of the pipe bend. These findings are consistent with the observed failure location and mode. Optimized design modifications are proposed and validated to enhance cavitation resistance of the pipe and prevent such failures.
Adoption of product innovation via development of coatings from solid wastes can boost the socio-economic development of a nation and facilitate climate action by reducing over-reliance on petroleum-based polymers. In this study, corrosion of A36 steel in 1 M HCl solution was protected using epoxy coatings enhanced with FeSO4/FeCl3 and silane-functionalised rice husk nanosilica. Inhibition efficiencies of synthesised organic epoxy coatings were evaluated using weight loss and electrochemical methods. At optimum conditions (100 degrees C, 3 days, 6 wt% and 120 rpm), the enhanced epoxy coating exhibited inhibition efficiency of 98.71%. The corrosion potential (Ecorr) and corrosion current density (Icorr) reduced from -0.6 V to -0.44 V; and 1.11 mu A/cm2 to 0.46 mu A/cm2, respectively, while the inhibition efficiency increased from 97.64% to 99.02% when the enhancer concentration was increased from 2 wt% to 6 wt%. Impedance spectra revealed an increase in the capacitive arc radius with increasing the enhancer concentration. The value of Rct for the blank, epoxy and enhanced epoxy was observed to be 28.86 +/- 0.29 Omega cm2, 44.88 +/- 1.81 Omega cm2 and 129.55 +/- 3.35 Omega cm2, respectively. As the epoxy was enhanced further, epsilon EIS increased from 35.70% to 77.72% while Cdl increased from 0.006 to 2.185 & micro;F cm-2.
Reliably predicting and characterising corrosion is a fundamental requirement for effective corrosion control in petrochemical plants, particularly for process pipelines that frequently experience corrosion leaks due to corrosive environmental influences. Traditional corrosion monitoring and detection methods have certain limitations in terms of timeliness and scope when identifying pipeline corrosion conditions. This paper proposes a data mining-based approach for predicting the corrosion state of process pipelines in petrochemical plants and further characterises the correlation relationships of key influencing factors. By analysing the characteristics of multi-source corrosion-related data from different types of petrochemical process pipelines and performing data preprocessing, a corrosion rate prediction model was established using genetic algorithm-optimised Gradient Boosting Regression Tree. The model achieved an RMSE of 0.0125, MAE of 0.0090 and R 2 of 0.940. Subsequently, through the Spearman correlation coefficient method and Apriori association rule mining algorithm, pressure, chloride ion concentration, temperature, flow rate, sulphide ion concentration and iron ion concentration were identified as key factors influencing the corrosion rate. Based on the proposed association rule construction method, quantitative patterns were revealed, such as a significant increase in corrosion rate (>0.3 mm/a) when the sulphide ion concentration exceeds 120 mg/L, the flow rate exceeds 80 m 3 /h or the pressure exceeds 0.8 MPa. This paper provides a scientific basis and guidance for identifying potential safety hazards and implementing precise corrosion control in petrochemical plants.
