Corrosion Issues Research Articles

Unraveling the impact of pH, sodium concentration, and medium osmolality on Vibrio natriegens in batch processes

BackgroundVibrio natriegens, a halophilic marine γ-proteobacterium, holds immense biotechnological potential due to its remarkably short generation time of under ten minutes. However, the highest growth rates have been primarily observed on complex media, which often suffer from batch-to-batch variability affecting process stability and performance. Consistent bioprocesses necessitate the use of chemically defined media, which are usually optimized for fermenters with pH and dissolved oxygen tension (DOT) regulation, both of which are not applied during early-stage cultivations in shake flasks or microtiter plates. Existing studies on V. natriegens’ growth on mineral media report partially conflicting results, and a comprehensive study examining the combined effects of pH buffering, sodium concentration, and medium osmolality is lacking.ResultsThis study evaluates the influence of sodium concentration, pH buffering, and medium osmolality on the growth of V. natriegens under unregulated small-scale conditions. The maximum growth rate, time of glucose depletion, as well as the onset of stationary phase were observed through online-monitoring the oxygen transfer rate. The results revealed optimal growth conditions at an initial pH of 8.0 with a minimum of 300 mM MOPS buffer for media containing 20 g/L glucose or 180 mM MOPS for media with 10 g/L glucose. Optimal sodium chloride supplementation was found to be between 7.5 and 15 g/L, lower than previously reported ranges. This is advantageous for reducing industrial corrosion issues. Additionally, an osmolality range of 1 to 1.6 Osmol/kg was determined to be optimal for growth. Under these optimized conditions, V. natriegens achieved a growth rate of 1.97 ± 0.13 1/h over a period of 1 h at 37 °C, the highest reported rate for this organism on a mineral medium.ConclusionThis study provides guidelines for cultivating V. natriegens in early-stage laboratory settings without pH and DOT regulation. The findings suggest a lower optimal sodium chloride range than previously reported and establish an osmolality window for optimal growth, thereby advancing the understanding of V. natriegens’ physiology. In addition, this study offers a foundation for future research into the effects of different ions and carbon sources on V. natriegens.

تحديد العمر المتبقي لأوعية الضغط الأسطوانية باستخدام تقنية الفحص بالموجات فوق الصوتية: دراسة حالة

Pressurized pressure vessels utilized in the upstream sector of the oil and gas industry commonly experience in-service deterioration caused by factors such as corrosion and process-related issues. Most current research has emphasized the significance of calculating remaining lifetime (RLT) but with a little concentration on the Ultrasonic test (UT) for remaining life assessment. In this work, a case study of the pressure vessel unit (20-v-200) belonging to Basra Oil Company (BOC) at Hammar Mishrif Degassing Station (HM-DGS) is conducted. A nondestructive test (NDT) by UT technique was employed over the suspected area of the pressure vessel. Where it was identified the condition monitoring locations (CMLs) around the shell and heads of the pressure vessel, were marked twenty-one locations to obtain their wall thickness measurement. The results of the remaining lifetime showed that for shell and head were computed as 52.9 years and 56.8 years, respectively. Therefore, based on the present result, it can be deduced that the pressure vessel can remain in operation or continue to be in service for the next 52.9 years under the same process conditions. This assessment considers the existing condition of the vessel and indicates that it can meet the required safety and operational standards for an extended duration. However, as an experienced entrepreneur, I would advise that thickness measurement inspections should be conducted within a timeframe that does not exceed either half of the remaining life of the vessel or a maximum of 10 years, according to API 510. This recommendation ensures that regular assessments are performed to monitor the thickness and condition of the vessel. By adhering to this practice, timely maintenance and necessary repairs can be identified and carried out, contributing to the continued integrity and safety of the vessel throughout its operational lifespan.

A Low-Acidity Chloride Electrolyte Enables Exceptional Reversibility and Stability in Aqueous Tin Metal Batteries.

Tin (Sn) metal has emerged as a promising anode for aqueous batteries, due to its high capacity, non-toxicity, and cost-effectiveness. However, Sn metal has often been coupled with strong and corrosive sulfuric acids (2-3 M), leading to severe electrode corrosion and hydrogen evolution issues. Although high efficiency and long cycling were reported, the results were achieved using high currents to kinetically mask electrode-electrolyte side reactions. Herein, we introduce a low-acidity tin chloride electrolyte (pH=1.09) as a more viable option, which eliminates the need of strong acids and enables a reversible dendrite-free Sn plating chemistry. Remarkably, the plating efficiency approaches unity (99.97 %) under standard testing conditions (1 mA cm-2 for 1 mAh cm-2), which maintains high at 99.23-99.93 % across various aggressive conditions, including low current (0.1-0.25 mA cm-2), high capacity (5-10 mAh cm-2), and extended resting time (24-72 hours). The battery calendar life is further prolonged to 3064 hours, significantly surpassing literature reports. Additionally, we presented an effective method to mitigate the potential Sn2+ oxidization issue on the cathode, demonstrating long-cycling Sn||LiMn2O4 hybrid batteries. This work offers critical insights for developing highly reversible Sn metal batteries.

Effects of marine environment and fatigue pre-damage on the residual tensile properties of SFCBs

Steel-fiber reinforced polymer (FRP) composite bars (SFCBs) present a promising solution to corrosion issues associated with conventional reinforcement in marine environments, offering a viable alternative. While the performance of SFCBs under marine environments or fatigue loading is well understood, their behavior under combined conditions remains unreported. This study conducted tension-tension fatigue tests on seawater-immersed SFCBs to assess the effects of fatigue loading (at a stress level of 0.36), various aging temperatures (23°C, 40°C, and 60°C), and durations (30, 180, and 360 days) on their residual properties. Microscopic analysis was used to investigate the degradation mechanisms due to environmental aging. The results indicate that environmental aging deteriorates the GFRP matrix in the outer layer of SFCBs, with fatigue loading further causing matrix cracking and reducing the quasi-static tensile strength. The residual tensile strength of SFCBs decreases with increasing aging times or temperatures, while aging shows no significant effect on their fatigue life. Additionally, a model predicting the residual tensile strength of SFCBs based on damage accumulation was proposed. According to the model, tensile strength initially rapidly decreases with aging time and eventually stabilizes. These findings offer practical insights for the application of SFCBs in concrete structures.

In-Vitro Investigation on the Tribological Properties of Nickel-Titanium (NiTi) Alloy Used in Braided Vascular Stents

The integration of diverse weaving angles in vascular stent design proves beneficial for addressing complex applications such as bending, branching, and load-bearing. However, the weaving process may introduce frictional corrosion issues among threads, necessitating further investigation into frictional behaviors at different weaving angles. This study simplifies the contact between nickel-titanium (NiTi) alloy threads in woven stents as line-to-line contact between rods. A proposed in vitro experiment, based on weaving angles of 30°, 45°, 60°, 75°, and 90°, systematically analyzes friction and wear characteristics, including friction coefficients, wear parameters, and morphology. Findings indicate significant impacts of weaving angles on tribological behaviors, with 30° weaving angle stents exhibiting the lowest wear rate. The study identifies four developmental stages in the life cycle of line-to-line contact wear: breaking-in wear, steady wear, severe wear, and post-stable wear. Under 25% calf serum lubrication, lower friction coefficients and wear rates are observed, validating NiTi alloy suitability for lubricated human environments. The investigation reveals a nonlinear correlation between weaving angles, friction cycles, and wear rates, offering insights for the tribological design of woven instruments.

Electrochemical and corrosion behavior of steel rebars in concrete exposed to industrial SO2 and CO2 environment

Investigation into the corrosion mechanism of steel rebars in concrete under the combined influence of SO2 and CO2 is crucial for addressing the corrosion issues in reinforced concrete structures exposed to industrial environments. This study investigated the electrochemical and corrosion behavior of steel rebars in concrete under the combined influence of SO2 and CO2 using electrochemical methods, pH and SO42- concentration tests at the concrete/steel matrix interface, and surface analysis. During the corrosion process, a competitive chemical reaction between SO2 and CO2 occurs. The electrical resistance (Rc) of the concrete cover layer undergoes initial rapid growth, followed by slower increments, and then another period of rapid growth before eventually stabilizing. However, Rc sharply decreases over time, corrosion-induced damage in the concrete cover layer. CO2 diffuses to the vicinity of the rebar before SO2, inducing rebar depassivation. As rust severity increases, significant changes in the rust products are observed, with Fe(III) compounds transforming into Fe(II) compounds, and FeSO4·4H2O and FeSO4·7 H2O are prevalent in the rust products. Furthermore, the formation of ferrous sulfate compounds can lead to local acidification, thereby accelerating the corrosion rate, and hastening the aging and deterioration of the structure, posing a serious threat to the safety of the building structure.

Corrosion-Resistant Ultrathin Cu Film Deposited on N-Doped Amorphous Carbon Film Substrate and Its Use for Crumpleable Circuit Board.

Copper (Cu) is widely used as an industrial electrode due to its high electrical conductivity, mechanical properties, and cost-effectiveness. However, Cu is susceptible to corrosion, which degrades device performance over time. Although various methods (alloying, physical passivation, surface treatment, etc.) are introduced to address the corrosion issue, they can cause decreased conductivity or vertical insulation. Here, using the nitrogen-doped amorphous carbon (a-C:N) thin film is proposed as a substrate on which Cu is directly deposited. This simple method significantly inhibits corrosion of ultrathin Cu (<20nm) films in humid conditions, enabling the fabrication of ultrathin electronic circuit boards without corrosion under ambient conditions. This study investigates the origin of corrosion resistance through comprehensive microscopic/spectroscopic characterizations and density-functional theory (DFT) calculations: i) diffusion of Cu atoms into the a-C:N driven by stable C-Cu-N bond formation, ii) diffusion of N atoms from the a-C:N to the Cu layer heading the top surface, which is the thermodynamically preferred location for N, and iii) the doped N atoms in Cu layer suppress the inclusion of O into the Cu lattice. By leveraging the ultrathinness and deformability of the circuit board, a transparent electrode and a crumpleable LED lighting device are demonstrated.

Key Strategies for Continuous Seawater Splitting for Hydrogen Production: From Principles and Catalyst Materials to Electrolyzer Engineering

AbstractDue to the high cost of ultra‐pure water supply and the mismatch between water sources and renewable energy distribution, the large‐scale production of green hydrogen through seawater electrolysis has generated significant interest. This presents an attractive potential technology within the framework of carbon‐neutral energy production. However, owing to the complex composition of seawater, particularly the competitive oxidation reactions and corrosion issues involving Cl−, seawater electrolysis has suffered from low selectivity and poor stability in oxygen evolution reaction (OER), which severely impact the efficiency of hydrogen production and hinder the practical applications. To further promote in‐depth research and practical applications of seawater electrolysis, this review introduces the principles, key advantages, and challenges of seawater electrolysis. Specifically, the design strategies are categorized for highly active OER electrocatalysts for seawater electrolysis, including catalyst design, design of chemical reaction systems, and other special process design. To ensure long‐term operational stability of seawater electrolysis, various strategies such as employing self‐supporting materials, surface protection strategies, and electrolyzer design, are discussed. Finally, current challenges and future prospects for the industrialization of seawater electrolysis are proposed and discussed. It is expected that this review provides new insights for large‐scale seawater‐based hydrogen production in the future.

Enhancing tribological performance of high‐density polyethylene polymer with diamond‐like carbon coating and mollusk shells filler

AbstractThis study explores the tribological properties of mollusk‐shell‐high‐density polyethylene (MS‐HDPE) biocomposites and diamond‐like carbon (DLC)‐coated metal beads as potential substitutes for hip joint prostheses. HDPE biocomposites with 0, 5, and 10 wt% of MS were developed using hot compression molding. Coatings included pure DLC, DLC‐Si, and DLC W:H. Wear tests on a ball‐on‐disk tribometer examined friction and wear rates against coated and uncoated balls, along with wear morphology. MS‐HDPE demonstrated superior tribological performance against DLC, achieving a 67% reduction in specific wear rate compared to pure HDPE. The study suggests that 5 wt% MS‐HDPE coupled with a DLC‐coated counterpart coating could be a promising combination for orthopedic applications, presenting a potential solution to metal corrosion and wear debris issues in orthopedic implants.Highlights Tested coatings: DLC, DLC‐Si, and DLC W:H. Biocomposite wear versus coated balls. DLC coating improves wear with shell fillers. Mollusk shell strengthens biocomposites. Reduced wear rate by 63% and friction by 77%.

AlGaAs as an Alternative Solar Water Splitting Material: Insights into Performance, Stability, and Future Directions.

This study offers an in-depth examination of aluminum gallium arsenide (AlGaAs) as a high-performance and durable material for photoelectrochemical water splitting, a key method of cost-effective renewable hydrogen production. Purpose-designed pin-AlGaAs photocathodes are demonstrated to yield a remarkable photocurrent density of over 15 mA/cm2 and an impressive onset potential of 1.11 V vs RHE. These results significantly outperform those achieved with other materials, marking a considerable advancement in the field. Moreover, this work addresses the long-standing issue of AlGaAs corrosion in an aqueous electrolyte. An innovative approach using a 60 nm TiO2 protection layer is introduced, providing substantial corrosion resistance in acidic environments and thereby enhancing material durability. This research also provides valuable insights into the role of passivation layers on charge transfer. It was found that an n-GaAs passivation layer further enhances the onset potential, whereas an n-InGaP layer contributes to a decline in the overall performance. These findings pave the way for new applications of AlGaAs in solar water splitting technology, offering a promising pathway toward the development of efficient AlGaAs/Si tandem water splitting devices.

Thermally stable and anti-corrosive polydimethyl siloxane composite coatings based on nanoforms of boron nitride

Coating technology has been emerged as a recognized and cost-effective approach in regard to mitigating issues that are linked to corrosion. We employed in-house synthesized boron nitride nanosheets (BNNS-CVD) and commercially available nanosized boron nitride (BN-nano) as fillers in this study to fabricate composite coatings with enhanced thermal stability and corrosion resistance. These fillers were dispersed in polydimethylsiloxane (PDMS) resin to develop composite coatings. The Fourier-transform infrared spectroscopy (FTIR), UV–visible spectroscopy, field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), and electrochemical impedance spectroscopy (EIS) were employed to characterize the prepared composite coatings. The FTIR analysis revealed a prominent absorption band around 1350 cm−1 that is indication of the distinctive B-N in-plane bending vibrations characteristic of boron nitride (BN). The FESEM images simultaneously confirmed the sheet-like morphology of both BN-nano and BNNS-CVD, which both found to be uniformly dispersed in the PDMS matrix. The EIS revealed that the composite films based on BNNS-CVD exhibited superior corrosion resistance compared to those based on BN-nano when exposed to a 3.5 wt% NaCl solution. Further, TGA profiles indicated that the composite films maintained their structural integrity up to 200 ℃ without degradation. Therefore, thermally stable and corrosion resistant coatings can be valuable for various new technology applications that involve corrosion issues.

Guidance for Residents Addressing Copper Problems in Drinking Water: Opportunities and Challenges.

Residents and their pets may experience aesthetic or health concerns resulting from elevated copper in their drinking water. The United States Environmental Protection Agency Lead and Copper Rule focuses on addressing systemwide corrosion issues, but gaps in the rule leave some municipal water consumers and residents with private well water vulnerable to high cuprosolvency. We developed guidance to aid residents in understanding, detecting, and addressing cuprosolvency issues in their drinking water. Three types of at-home test kits for copper and one for pH were determined to be accurate enough (R 2 > 0.9 (lab, based on average values from n = 5 replicates each) and >0.7 (field)) to detect concerns related to high cuprosolvency and inform selection of intervention options. Case study results indicate that, although water treatments such as increasing pH on-site may be effective, long-term treatment (>36 weeks or permanently) may be needed to maintain reductions in cuprosolvency. A decision tree is provided to help residents and citizen scientists navigate these concerns for both public water systems and private wells.

Research on Acid Aging and Damage Pattern Recognition of Glass Fiber-Reinforced Plastic Oil and Gas Gathering Pipelines Based on Acoustic Emission.

Pipelines extend thousands of kilometers to transport and distribute oil and gas. Given the challenges often faced with corrosion, fatigue, and other issues in steel pipes, the demand for glass fiber-reinforced plastic (GFRP) pipes is increasing in oil and gas gathering and transmission systems. However, the medium that is transported through these pipelines contains multiple acid gases such as CO2 and H2S, as well as ions including Cl-, Ca2+, Mg2+, SO42-, CO32-, and HCO3-. These substances can cause a series of problems, such as aging, debonding, delamination, and fracture. In this study, a series of aging damage experiments were conducted on V-shaped defect GFRP pipes with depths of 2 mm and 5 mm. The aging and failure of GFRP were studied under the combined effects of external force and acidic solution using acoustic emission (AE) techniques. It was found that the acidic aging solution promoted matrix damage, fiber/matrix desorption, and delamination damage in GFRP pipes over a short period. However, the overall aging effect was relatively weak. Based on the experimental data, the SSA-LSSVM algorithm was proposed and applied to the damage pattern recognition of GFRP. An average recognition rate of up to 90% was achieved, indicating that this method is highly suitable for analyzing AE signals related to GFRP damage.

Model for the Failure Prediction Mechanism of In-Service Pipelines Based on IoT Technology

With the rapid increase in pipeline mileage in China, the accurate prediction of corrosion issues in in-service pipelines has become crucial for ensuring safe pipeline operation. Traditional pipeline leakage monitoring methods are significantly limited by human factors and equipment precision, making it challenging to predict and identify leakage points accurately. Therefore, aligned with the trend of intelligent pipeline development, this study aims to construct a failure pressure prediction mechanism model for corroded pipelines based on IoT technology. This model leverages intelligent sensing and prediction to assess the safety status of corroded pipeline sections. Ultrasonic phased array technology detects specific corrosion points and detailed defect parameters within pipeline sections. The parameters are then utilized in the Simdroid domestic finite element analysis model to simulate the ultimate burst pressure of the pipeline. A single-variable approach is employed to analyze the sensitivity of different parameters to the pipeline’s ultimate burst pressure, with the minimum burst pressure point of multi-point corroded sections selected as the overall segment failure pressure. Finite element simulation data are integrated into a neural network database to predict the pipeline failure pressure. The real-time operational data of the pipeline are monitored using negative-pressure wave sensing. The operational pressure of the corroded points is compared with the algorithm-predicted failure pressure; if the values approach a critical threshold, an alarm is triggered. Moreover, the remote control terminals evaluate the pipeline’s self-rescue time, providing a buffer for pipeline leakage self-rescue. The failure prediction mechanism model for in-service pipelines was applied to the Fujian–Guangdong branch of the West–East Gas Pipeline III to verify its accuracy and feasibility. The research results offer technical support for the maintenance and emergency repair of pipeline leakage scenarios, leveraging intelligent pipeline technology to reduce costs and increase the efficiency of pipeline operations, thereby supporting the sustainable development of China’s oil and gas pipelines with theoretical and technical backing.

N-vinylcaprolactam-acrylamide copolymer inhibition performance against 304L stainless steel corrosion in a simulated sweet-sour corrosive environment

Internal corrosion of oilfield pipes in the presence of CO2 and H2S is a significant problem in the oil and gas industry. The financial and material ramifications are immense, given that transportation pipelines are vital to the energy and gas industry. In typical oilfield industries, the prevailing approach to address corrosion issues affecting steel-based structural elements involves the incorporation of corrosion inhibitors into the corrosion system. In this study we evaluated the effectiveness of an N-vinylcaprolactam-acrylamide copolymer (NVAM) in inhibiting the corrosion of stainless steel in a 3.5% NaCl solution saturated with CO2 and containing 100 ppm H2S, which simulates a sweet/sour corrosive environment typical of oilfields Several experimental methods, such as weight loss, electrochemical techniques and surface characterization methodologies (SEM, EDS, & AFM) were used to assess the inhibitor's efficacy. The inhibitor demonstrated remarkable performance, attaining an approximately 90 % inhibition efficiency at a 100 ppm concentration. Adsorption of Poly(NVAM) adhered to the Langmuir adsorption model and functioned primarily as a cathodic inhibitor. The results obtained from the analysis of SEM, EDS, and AFM indicate that poly(NVAM) forms a protective film on the surface of the steel, thereby impeding the access of corrosive species. The protective film efficiently prevented corrosive chemicals from reaching the steel's surface.

Research Progress on Influencing Factors of Erosion Corrosion in Oil Pipelines

Original sentence: &amp;quot;Erosion corrosion is a significant factor contributing to the thinning and failure of oil pipelines. This paper addresses the issue of erosion corrosion of oil pipelines in oil fields under the action of multiphase flow, the main factors affecting the erosion corrosion are introduced, including the hydrodynamic factors, solid particle properties, fluid medium properties and temperature, It summarizes and analyzes the mechanisms through which these different factors affect the erosion corrosion of oil pipelines. The paper points out that increased fluid velocity in oil pipelines, sudden changes in flow patterns, and turbulent kinetic energy can accelerate erosion corrosion to some extent, With the increase of flow rate, erosion corrosion mechanism will change from electrochemical corrosion dominant to erosion accelerated corrosion, There is a maximum value for erosion corrosion based on the solid particle impact angle. The harder and sharper the solid particles are, the stronger their impact on the pipeline, especially the impact of low Angle impact is more significant; however, the diameter and quantity of particles can affect the development of erosion corrosion due to &amp;apos;particle size effect&amp;apos; and &amp;apos;shielding effect.&amp;apos; Additionally, lower pH values and higher temperatures of the fluid medium will increase pipeline erosion corrosion. Finally, future research directions for studying erosion corrosion in oilfield pipelines under multiphase flow conditions are discussed in light of existing research.&amp;quot;

Interfacial structure and properties of anodized 6061 Al alloy joints by ultrasonic-assisted hot dipping and soldering using a Sn–9Zn–2Al filler metal

Al alloy joints soldered with Sn-based filler metal are susceptible to corrosion and early failure when exposed to moisture, resulting in severe accidents and substantial economic losses. This study proposes a method to prevent galvanic corrosion by separating Al alloys and Sn-based filler metals with an insulating barrier layer of anodized aluminum oxide (AAO) composed of Al2O3. The successful joining of anodized aluminum alloy (AAA) with Sn–9Zn–2Al was achieved through ultrasonic-assisted hot dipping and soldering in air at 240 °C. Microstructural examination revealed strong bonding between the solder alloy and AAO, with the solder infiltrating the AAO nanotubes and a transition layer consisting of two sublayers at the interface: amorphous ZnO mixed with nanocrystals (ZnO and Al2O3) and amorphous Al2O3. The shear strength of the joints ranged from 31.8 to 32.8 MPa when subjected to ultrasonic hot dipping for 0.5–2.0 s, with no significant difference observed. Fracture initiation and propagation occur within the transition layer at the interface. The shear strength of joints subjected to dipping for more than 3.0 s decreased slightly to 27.9 MPa due to localized peeling off of AAO from the Al substrate. The formation of the interface involves the segregation of Al and Zn on the liquid filler metal surface, driven by differences in atomic activity. Due to the jet force from cavitation, an Al-rich liquid infiltrates the nanotube, resulting in the formation of Zn–O at the interface and Al–O both at the interface and within the nanotube. Throughout this process, the wetting model shifts from a Cassie state to a near-Wenzel state. Immersion tests of two types of joints, Al/SnZnAl/Al and AAA/SnZnAl/AAA, confirmed that galvanic corrosion of Sn/Al was completely inhibited by the latter. Consequently, AAA joints demonstrate excellent corrosion resistance, validating this approach as a promising solution to the Al/Sn galvanic corrosion issue.

Deep neural networks for external corrosion classification in industrial above-ground storage tanks

This paper uses transfer learning and fine-tuning approaches to explore EfficientNet smaller models for a multiclassification task of corrosion types in above-ground storage tanks. Data augmentation was used to increment the data an oil and gas company provided, reaching a dataset of around 5000 images. The images were stored in Google Drive and imported into Colab to train the models using TensorFlow and Keras. After the hyperparameters’ tuning a transfer learning model was selected and explored with fine-tuning. The EfficientNetB0 model delivered from fine-tuning accomplished 94 % performance. This work is the first attempt to deploy an artificial vision automatic tool for being implemented during tank inspection in the industrial sector. In further development, this model can be coupled with one based on object detection to remotely identify failures due to external corrosion issues, improving safety and reliability in oil and gas operations.

Dual-metal-based (Mo, Ni) MOFs nanoplates for enhanced corrosion resistance and frictional resistance of epoxy resin on magnesium alloy surfaces

Magnesium alloys face severe corrosion issues due to their high electrochemical activity. In recent years, polymer coatings containing metal-organic frameworks (MOFs) have shown great potential in improving the corrosion resistance of metals. In this study, nickel salts and molybdate were used as metal sources, and 4,4′-bipyridine was used as the organic ligand. For the first time, a nickel and molybdenum-based metal-organic framework (Mo-Ni-MOF) was synthesized via hydrothermal method. Mo-Ni-MOFs were then incorporated as nanofillers into epoxy resin and coated on AK61M magnesium alloy to enhance its long-term corrosion resistance. Characterization tests including FT-IR, FE-SEM, EDX, XRD and XPS confirmed the successful reaction between metal ions and organic ligands, indicating successful coordination. TEM analysis revealed that the MOFs consisted of nanosheets with diameters ranging from 20 to 100 nm. BET analysis demonstrated the porous structure of the synthesized nanoparticles, with a high specific surface area ranging from 6 to 44 m2.g−1 and an average pore size ranging from 9 to 32 nm. Salt spray tests demonstrated that MOFs synthesized under different conditions exhibited superior long-term corrosion resistance compared to pure epoxy coatings in artificial scratch coating performance. Electrochemical impedance spectroscopy (EIS) testing revealed a three-order-of-magnitude enhancement in |Z| at 0.01 Hz for the most effective MOF compared to pure epoxy resin. Tafel tests showed a significant decrease in corrosion current, with reductions of 2–3 orders of magnitude. Friction tests revealed a decrease in the coefficient of friction after the addition of MOFs, with reductions ranging from 0.1 to 0.4, indicating improved durability of the coating against friction.

Research on the manufacturing of nickel coatings by jet electrodeposition after laser pretreatment with different media

This study aims to address the corrosion issues faced by 45 steel to meet its usage requirements and propose a method combining liquid-phase assisted laser and jet electrodeposition. In this method, the sample surface was the first laser pretreated in different media, and then Ni was deposited on its surface using jet electrodeposition. This paper investigates in detail the effects of laser pretreatment on the surface quality of nickel coating after jet electrodeposition in four different media (Air, Water, Saturated NaHCO3, 95%C2H5OH+5%H2O2). The experimental results indicate that liquid-phase assisted laser pretreatment had improved the surface quality of Ni coating. Especially after laser pretreatment in saturated NaHCO3 medium, the adhesion of the deposited coating increased by 50% compared to air, and the roughness decreased from 20.945 μm in the air to 0.373 μm. The corrosion current density decreased from 120.2 μA·cm−2 on the substrate to 1.605 μA·cm−2.