Search Results (132)

This study focuses on a group of scanning electrochemical probe microscopies used to reveal the early stages of galvanic coupling corrosion reactions, based on the use of microelectrochemical sensors for measuring local potentials and currents associated with chemical reactions occurring at anodic and cathodic sites, and their correlation with results obtained with conventional electrochemical techniques. Although galvanic corrosion between dissimilar metals is generally analyzed by assuming that the anodic and cathodic half-cell processes occur in different metals, the use of microelectrochemical techniques reveals that the corrosion process is actually more heterogeneous. Cathodic activity is present in both metals, but to very different degrees. Anodic activity is also localized, as the surface of the more reactive metal is not fully available to undergo anodic dissolution. Because galvanic corrosion processes are heterogeneously distributed over the surface of the coupled materials, even in model systems, the identification of cathodic sites and reactions is often insufficient when monitored by conventional electrochemical methods. These observations are particularly relevant when corrosion protection measures aim to minimize or eliminate the activity of cathodic reaction sites. Full article

In this study, cathodic arc deposition was employed to synthesize CrAlN/TiSiN nanostructured multilayer coatings on silicon wafer substrates. The effects of the multilayer architecture on the microstructure and corrosion resistance of the coatings were systematically investigated. The structural characteristics and performance of the deposited films were analyzed using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and electrochemical polarization measurements. The experimental results demonstrate that various CrAlN/TiSiN multilayer configurations were successfully deposited, forming dense multilayer coatings with a thickness of approximately 1–2 μm and a dominant FCC β₁-NaCl crystalline structure. The presence of nanostructured multilayer interfaces effectively inhibited columnar grain growth and contributed to microstructural refinement. XRD analysis revealed competitive growth between the (111) and (200) crystallographic orientations, indicating that the crystallization behavior is influenced by the interplay between surface energy minimization and strain energy accumulation. Contact angle measurements showed that all the coatings exhibited water contact angles exceeding 90°, indicating hydrophobic characteristics and potential anti-fouling capacity. In particular, the CrAlN outer layer structure presented lower surface free energy, which further enhances the coating system’s anti-fouling capacity. Electrochemical polarization results indicate that the corrosion current density of all the coatings remained in the order of 10⁻⁷ A/cm², demonstrating excellent chemical stability. Overall, the CrAlN/TiSiN nanostructured multilayer coatings exhibit pronounced interface strengthening and densification growth mechanisms, which effectively enhance the chemical stability of silicon-based material surfaces. These results could provide valuable insights for the structural design and optimization of high-performance protective coatings. Full article

The development of highly efficient and stable photoanodes is essential for advancing photoelectrochemical cathodic protection towards practical applications. Herein, a novel ternary sulfide heterojunction was engineered through the construction of a three-dimensional interlocked architecture of ZnIn₂S₄ on SnIn₄S₈ nanosheets via a sequential hydrothermal synthesis. This unique three-dimensional interlocked configuration creates an intimate interface and continuous charge transfer highways, effectively addressing the slow electron movement and poor interfacial contact that plague conventional photoelectrodes. Spectroscopic and electrochemical analyses verified the formation of a Type-II band alignment, which drives the directional migration of photogenerated electrons from ZnIn₂S₄ to SnIn₄S₈ under an intrinsic built-in electric field. Upon coupling with 304 stainless steel, the ZnIn₂S₄/SnIn₄S₃ heterojunction exhibited outstanding photoelectrochemical cathodic protection performance. It delivered impressive photocurrent densities of 15.22, 19.76, and 72.27 μA·cm⁻² in 3.5 wt% NaCl, 0.1 M Na₂S₂O₃, and 0.1 M Na₂S/NaOH electrolytes, respectively, along with a prominent 720 mV cathodic potential shift in the Na₂S/NaOH system. Most importantly, its good activity and stability in the scavenger-free 3.5 wt% NaCl solution and natural seawater highlight the strong practical potential of this 3D interlocked photoanode for sustainable marine metal corrosion control. Through a strategic multi-electrolyte assessment, the underlying protection mechanisms were decoupled, revealing that the synergy between the heterojunction-induced charge separation enabled by the three-dimensional interlocked structure and electrolyte-specific hole scavenging is key to the enhanced performance. Full article

Corrosion and scaling critically threaten the safety and efficiency of oil–gas gathering stations. Through field inspections, water chemistry analysis, scale characterization, and corrosion simulation in Yanchang oilfield, this study identifies severe localized damage in key components—such as valves, bends, and injection pipelines—with service lives of only 1–2 years. Analysis of over 200 scale samples revealed that CaCO₃ (42 wt%) and CaSO₄ (23 wt%) were the predominant scale types. High salinity >56,000 mg/L, Cl⁻ >31,000 mg/L, and Ca²⁺ promote under-deposit pitting, galvanic corrosion (e.g., Cu–steel couples), and erosion-corrosion at high-velocity zones. Simulations based on OLI Analyzer Studio (a professional thermodynamic simulation software for electrolyte solution and high-salinity brine systems) reveal that the carbon steel (the primary material for the process pipelines and water injection pipelines in the studied oil–gas gathering and transportation stations) has a corrosion rate rising from 0.078 mm/year at 25 °C to 1.94 mm/year at 90 °C. Despite common use of coatings and cathodic protection, these measures often fail to address site-specific failure mechanisms. The study advocates a tailored mitigation strategy combining material compatibility, real-time water monitoring, optimized filtration, and component-level design. This integrated approach enhances asset reliability and operational safety in onshore oilfields. Full article

In nuclear power, marine engineering, and other fields, a matching system composed of duplex steel and copper alloy is a common combination for rotating components in a seawater environment. However, this system is susceptible to galvanic corrosion that seriously threatens its service safety and service life, with ZCuAl10Fe5Ni5 being the main component corroded. Additionally, current corrosion research on this system has evident gaps. Specifically, the influence of area ratio on galvanic corrosion remains insufficiently understood, and the action mechanism of Cl⁻ on the ZCuAl10Fe5Ni5-based corrosion product film in seawater, as well as the product evolution path, has not been fully revealed, which restricts the development of targeted protection technologies. This study explores the degradation mechanism of ZCuAl10Fe5Ni5 in a specific high-salinity environment (20,000 mg/L Cl⁻), characteristic of nuclear power plant service conditions. The results show that due to the significant electrode potential difference between the SAF2507 duplex steel and ZCuAl10Fe5Ni5 copper alloy, a stable galvanic couple is formed, with ZCuAl10Fe5Ni5 acting as the anode and undergoing dissolution corrosion. When the area ratio of ZCuAl10Fe5Ni5 (anode) to SAF2507 duplex steel (cathode) is 1:50, a significantly stronger galvanic effect is observed. The high concentration of Cl⁻ in seawater can damage the surface of the ZCuAl10Fe5Ni5-based corrosion product film, leading to intensified local corrosion. The ZCuAl10Fe5Ni5-derived corrosion products have a layered structure mainly comprising a mixed system of Cu-Al-Mg oxides/hydroxides, and the corrosion process is accompanied by selective aluminum depletion corrosion. This study provides insight into the corrosion mechanism and key influencing factors of ZCuAl10Fe5Ni5 in the matching system, as well as a theoretical basis and technical support for the design of compatibility metal materials in a seawater environment and the control of corrosion in ZCuAl10Fe5Ni5. Full article

Carbon dots (CDs) have demonstrated promising application prospects in the field of corrosion protection due to their small size, excellent dispersibility, abundant and tunable surface functional groups, low cost, environmental friendliness, and unique fluorescence properties. However, existing reviews have predominantly focused on the synthesis and photoluminescence properties of CDs, lacking systematic integration and in-depth mechanistic analysis of their diverse applications in corrosion protection. This review systematically summarizes the recent research progress and underlying mechanisms of CDs in five key areas: corrosion inhibitors, anticorrosive coatings, photogenerated cathodic protection, chloride binding, and corrosion monitoring. As corrosion inhibitors, CDs form compact protective films on metal surfaces through synergistic physical and chemical adsorption. In anticorrosive coatings, CDs not only enhance the physical barrier effect but also impart intelligent functionalities such as self-healing and corrosion monitoring. In the field of photogenerated cathodic protection, CDs broaden the light absorption range of semiconductors and facilitate the separation of photogenerated carriers. As chloride binding promoters, CDs promote the formation of cement hydration products, thereby improving the durability of reinforced concrete structures. As sensing platforms, CDs enable early visual detection of corrosion through their specific fluorescence response to ions such as Fe³⁺. Despite significant progress, challenges remain in scalable preparation, practical application performance in complex environments, and multifunctional integration. This review systematically outlines the research advancements of CDs in corrosion protection, providing a practical reference for subsequent studies and engineering applications. Future research should focus on scalable synthesis, machine learning-assisted design, and the development of integrated multifunctional protection systems to promote the practical application of CDs in the field of corrosion protection. Full article

Aqueous zinc-ion batteries (AZIBs) are promising for large-scale grid storage due to inherent safety, low cost, environmental compatibility, high theoretical capacity (820 mAhg⁻¹), and suitable redox potential (−0.763 V vs. SHE). However, practical deployment is hindered by coupled challenges at the zinc anode–hydrogen evolution, dendrite growth, and corrosion/passivation, which severely limit cycle life and coulombic efficiency. This review systematically summarizes key advances in AZIB research. It first elucidates working principles and four cathode energy storage mechanisms: Zn²⁺ insertion/extraction, H⁺/Zn²⁺ co-insertion, chemical conversion, and dissolution/deposition. Second, it examines four mainstream cathodes (manganese-based, vanadium-based, Prussian blue analogs, and organic compounds), analyzing performance bottlenecks and corresponding optimization via structural modification. Third, it explores functional mechanisms of advanced separators (polymer, inorganic/ceramic composite, MOF-based, and cellulose-based) in regulating uniform Zn²⁺ deposition and suppressing dendrites. Fourth, it summarizes anode optimization strategies: artificial protective layers for interface stabilization, electrolyte additives to modulate Zn²⁺ solvation/deposition, and 3D porous structures to reduce local current density and provide nucleation sites. Finally, key scientific challenges and future directions are discussed—multi-strategy synergy, in situ characterization, practical battery construction, and sustainable technological development, offering theoretical guidance for advancing AZIBs toward large-scale applications. This review aims to provide a comprehensive perspective spanning from materials to systems, and from mechanisms to applications. Its core objective is not merely to list the types of cathode materials, but to establish a logical bridge directly connecting “key challenges” to “optimization strategies,” with a particular emphasis on the issues and solutions related to the cathode side. Full article

The growing demand for higher-energy lithium-ion batteries, encompassing consumer electronics, stationary grid storage, and electric mobility to specialized sectors like aerospace, medical devices, and industrial robotics, requires cathode materials that offer higher capacity while remaining cost-effective. This trend has intensified the development of nickel-rich LiNi_1−x−yMn_xCo_yO₂ (NMC) systems. However, high-Ni NMCs such as LiNi_0.9Mn_0.05Co_0.05O₂ (NMC90) suffer from limited thermal and cycling stability. Core–shell architectures using LiNi_0.6Mn_0.2Co_0.2O₂ (NMC622) as a shell can partially alleviate these drawbacks, but structural degradation caused by interdiffusion between the core and shell persists as a major challenge. This study investigates whether a tungsten oxide interlayer can act as a protective barrier that suppresses interdiffusion, stabilizes the crystal structure, and improves long-term electrochemical performance. In this work, NMC cathode powders were synthesized via a one-pot oxalate co-precipitation route, followed by structural characterization using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and ion scattering spectroscopy (ISS). Electrochemical performance, including capacity retention, cycling stability, and internal resistance, was evaluated through galvanostatic charge–discharge (GCD) testing and electrochemical impedance spectroscopy (EIS). The core–shell configuration delivered higher specific discharge capacity compared to the individually synthesized core-only and shell-only reference materials, and the incorporation of a tungsten oxide interlayer resulted in a twofold increase in cycle life. These results demonstrate that tungsten oxide effectively enhances cycling stability by inhibiting core–shell interdiffusion, offering a promising pathway toward more durable high-Ni NMC cathodes. Full article

Reinforced concrete is currently the most widely used system in the construction industry due to its excellent properties, including its durability, workability, lifetime, and compressive strength. However, reinforced concrete structures have disadvantages, such as corrosion, that affect their performance and may even lead to unexpected and/or premature failures. The main cause of this type of failure is the presence of chlorides, mostly from seawater. In this context, cathodic protection is one of the most efficient methods for protecting reinforced steel from corrosion. However, it is very expensive due to the high resistivity of concrete. In this research work, it is proposed to modify concrete by partially replacing the fine aggregate with rPET and CBF, thus exploiting the mechanical properties of rPET to promote energy dissipation, mitigating the stresses to which the reinforced concrete system is exposed and increasing its compressive strength. Furthermore, due to its hygroscopicity, CBF is used to promote moisture retention and reduce the resistivity of the concrete, thus facilitating cathodic protection of the reinforcing steel through the impressed current. The results indicate that the presence of rPET increases the compressive strength of concrete by approximately 8% in comparison with the reference sample after 28 days of curing, while the presence of CBF reduces the resistivity of concrete, ultimately increasing the cathodic protection efficiency of the reinforcing steel. Full article

Spinel LiNi_0.5Mn_1.5O₄ (LNMO) has emerged as a highly competitive cobalt-free cathode material for higher-energy-density lithium-ion batteries. However, its practical application is hindered by severe capacity degradation, particularly under high-voltage operation. To solve this problem, we put forward a surface modification strategy employing a Li_0.4La_0.54TiO₃ (LLTO) coating. The LLTO coating forms a protective cathode–electrolyte interphase that helps to inhibit interfacial side reactions, enabling enhanced electrochemical performance up to 5 V. As a result, the optimized 1 wt% LLTO-coated LNMO exhibits a remarkable capacity retention of 96.5% after 200 cycles at 0.1 C and delivers a high-rate capacity of 103.5 mAh g⁻¹ at 2 C, significantly outperforming its pristine counterpart (86.8% and 89.6 mAh g⁻¹, respectively). This work provides a viable and efficient surface modification approach for achieving robust high-voltage LNMO cathode material, underscoring its great potential for next-generation energy storage systems. Full article

Chlorinated solvents such as vinyl chloride (VC) and trichloroethylene (TCE) represent a persistent threat to groundwater-derived drinking-water supplies, including riverbank filtration well fields in alluvial aquifers. This work presents a laboratory-scale evaluation of an electrochemical barrier concept for targeted VC and TCE removal performed using synthetic groundwater representative of a riverbank filtration setting in the Danube River basin. Experiments were conducted in a covered batch reactor equipped with Ti/IrO₂–RuO₂ mixed-metal-oxide anodes and Ti cathodes, systematically varying current intensity (10–60 mA), treatment time (0–60 min), active anode surface area (12–48 cm²), and inter-electrode distance (0.5–2.5 cm). At 60 mA, VC and TCE removals of 97% and 95%, respectively, were achieved within 20 min, while prolonged treatment to 60 min increased removal to about 99% for VC and 98.5% for TCE. Multivariate analysis (PCA) and correlation assessment identified applied current as the dominant control parameter, particularly for TCE removal, whereas electrode configuration and spacing played secondary roles within the investigated range. For the most cost-effective treatments meeting Serbian drinking-water criteria, estimated electricity costs were 0.39 €/m³ for VC and 0.10 €/m³ for TCE. Overall, the results demonstrate the technical feasibility and promising cost-effectiveness of electrochemical barriers as a proactive measure to protect riverbank filtration systems from future VC and TCE contamination n urban environments, while highlighting the need for follow-up studies on by-product formation and long-term performance. Full article

In order to explore the influence of different current forms on the protection effect of cathodic protection systems for intelligent test piles of oil and gas gathering and transportation pipelines, X80 steel was taken as the research object to simulate the soil corrosion environment, and cathodic protection performance test experiments were carried out under three current forms: direct current (DC), conventional pulse (P) and high-frequency pulse (HP). Through a polarization curve test, electrochemical impedance spectroscopy (EIS) analysis, surface morphology observation and corrosion rate test, the effects of three current forms on cathodic polarization effect, polarization resistance, corrosion product composition and protection efficiency were compared. The results show that high-frequency pulse current can make the pipeline steel reach the protection potential in a shorter time, and under the same average current density, its polarization resistance is 23.6% and 15.8% higher than that of DC and conventional pulse, respectively. The anti-interference ability of conventional pulse current is better than that of DC. In the presence of stray current, the fluctuation amplitude of protection potential is only 21.1% of DC. The protection stability of DC is good, but the polarization speed is slow, and the phenomenon of “over protection” easily occurs in the process of long-term protection. Combined with economic analysis, high-frequency pulse current has significant advantages in high-corrosion-risk environments. Conventional pulse is suitable for stray current interference areas, while DC is more suitable for long-distance pipeline protection with low corrosion risk. The research results can provide a theoretical basis and technical support for the selection of the current form of pipeline cathodic protection systems. Full article

This study investigated the degradation of aluminum-based sacrificial anodes caused by sulfate-reducing bacteria (SRB) in marine mud. Through self-discharge tests simulating real cathodic protection conditions, alongside macroscopic observations, electrochemical analysis, and microscopic characterization, we systematically elucidated the corrosion behavior and mechanisms of the anodes with and without SRB. The results showed that the electrochemical capacity of anodes in SRB-inoculated mud was only 1281.28 Ah·kg⁻¹ (efficiency: 44.82%), failing to meet the design requirement of ≥1500 Ah·kg⁻¹. In contrast, in sterile mud, the capacity was 1972.84 Ah·kg⁻¹ (efficiency: 69.01%), which met the standard. SRB promoted the formation of discrete corrosion pits with depths reaching up to 0.43 mm, 3.07 times deeper than those observed under sterile conditions. The local pH within the pits dropped to 3–4, accelerating the selective dissolution of active elements such as Al and Zn. Mechanistic analysis revealed that the sulfides produced by SRB not only disrupt the passive film but also exacerbate the inefficient consumption of the anode through a positive feedback loop involving “acidic corrosion and electron consumption”. This led to a reduction in the protective current density, accompanied by significant fluctuations. This study provides the underlying mechanisms by which SRB degrade the performance of sacrificial anodes and valuable insights for optimizing the design of cathodic protection systems for steel structures in marine mud environments. Full article

Impressed current cathodic protection (ICCP) systems can experience acidification, which deteriorates the interface between the anode and the anode backfill mortar. This deterioration may necessitate premature intervention to remove and reinstate the backfill and, in some cases, replace the anode. If left unaddressed, acidification ultimately leads to debonding between the anode and the backfill mortar, resulting in the failure of the ICCP system. This paper presents the development of a specialised acid-resistant hybrid mortar designed for ICCP systems used to protect reinforced concrete bridges in marine environments. It also investigates the effects of acidification on the physical and mechanical properties of the proposed anode backfill mortars. Additionally, the study characterises acidification products from both field-extracted ICCP systems and laboratory-based accelerated testing, providing deeper insights into the acidification mechanisms. Novel mortar samples were subjected to varying concentrations of hydrochloric acid (HCl) under accelerated testing conditions. The incorporation of supplementary cementitious materials (SCMs), calcium sulfoaluminate (CSA) cement and zeolite significantly enhanced the strength and durability of the backfill mortars in acidic environments, while maintaining compliance with the electrical resistivity requirements (20–100 kΩ·cm) for ICCP systems. The lowest compressive strength loss observed in the developed hybrid mortar was 54% after 28 days of immersion in 5% HCl and 83% in 15% HCl. Microstructural analyses revealed that gypsum formation and chloride–sulphate competitive binding interactions are key mechanisms contributing to the improved acid resistance, particularly in CSA cement-containing formulations. Full article

The promise of lithium–oxygen batteries lie not merely in their record-breaking theoretical energy density, but in the challenge of making such energy truly reversible. Rising as the key obstacle is the lithium metal anode, whose remarkable capacity and low potential come at the cost of dendritic growth, unstable solid electrolyte interphases, and relentless reactions with oxygen species. These instabilities, once overshadowed by cathode-related limitations, now define the frontier of research as current densities and energy demands approach practical levels. This review highlights recent progress in two complementary directions for anode protection: physical approaches, such as artificial protective layers, solid or functional separators, and oxygen-blocking interlayers that isolate and stabilize the surface; and chemical strategies, including electrolyte and additive design that enable in situ formation of LiF- and Li₃N-rich interfaces with high ionic conductivity and chemical robustness. Together, these approaches establish a unified framework for achieving dendrite-free and oxygen-resistant lithium interfaces. Mastering solid electrolyte interfacial stability rather than only cathode catalysis will ultimately determine whether lithium oxygen battery can evolve from laboratory prototypes to truly viable high-energy systems. Full article