Corrosion Prevention Research Articles

Study of Mechanical and Thermal Properties for Epoxy Grouts Subjected to Seawater Conditioning at Elevated Temperature: Tensile Test and Compressive Test

Pipelines and risers are major transportation of oil and gas. These components are often exposed to extreme marine environmental conditions that can cause pipelines to fail due to corrosion. Hence, epoxy grouts are used as a coating material on the surface of pipelines and risers for supporting the pipe structure and corrosion prevention. In this case, the efficiency of epoxy grout is important in pipeline rehabilitation. Research on the adaptation of seawater, temperature, and epoxy grouts is carried out to determine the changes in mechanical and thermal properties of the material. The preparation of epoxy grouts was prepared with a mixture of epoxy resins, epoxy hardeners, and aggregates. After the sample compounds have been flattened, the mixture will be put into the mold. The seawater aging process was performed for seven days before conducting laboratory experiments. After the seawater aging process, there were physical changes on the surface of the epoxy grouts which are the epoxy grout become harder and there were voids that can act as stress concentration points that may cause micro-crack on the specimen. Next, tensile (ASTM 638) experiments were performed at different temperatures of 27°C, 40°C, 52°C, 72°C, 80°C and 100°C while the result of compression experiment is based on the literature critique of past journals. Based on the result, the young modulus and ultimate tensile strength of the epoxy grouts are decreased with increasing temperature. The increment of temperature causes the epoxy grouts to become weaker due to the changes in the polymer matrix structure of the epoxy grouts which lead to the failure at low load and shortens the life of the material. In addition, epoxy grouts are amorphous materials where the glass transition temperature determine the mechanical and physical properties of epoxy grouts. Therefore, the results of the study found that the epoxy grouts changed its mechanical properties from brittle to ductile when the temperature is at 72°C. From the comparison between samples immersed and not immersed in seawater, there is a decrease in Young’s modulus, ultimate tensile stress and strain due to the effect of seawater reaction. In conclusion, the increment in temperature and seawater adaptation factors affect the strength and durability of epoxy grouts.

Improving the Corrosion Resistance of TNTZ in Hanks’ Solution after Thermomechanical Treatment

Ti-29Nb-13Ta-4.6Zr (TNTZ) is a new titanium alloy potentially to be used as bone implant material because of its advantages in terms of strength, ductility, non-toxicity, corrosion resistance, and biocompatibility. Its mechanical properties are suitable for bone applications; however, there are still problems related to its corrosion behavior when used for a long time. Therefore, this research aims to determine the corrosion rate and types, and provide corrosion prevention by applying the thermomechanical treatment on TNTZ in Hanks’ solution. The limitation of this research was in not conducting the TNTZ biocompatibility tests. This research was conducted using the potentiodynamic polarization method in Hanks’ solution as the corrosive medium at a temperature of 37°C and a pH of 6.8. Before corrosion testing, a TNTZ sample was treated with thermomechanical treatment combined with solution treatment at a temperature of 850°C and a holding time of 45 minutes, followed by rapid cooling (water quenching), and plastic deformation with deformation variations of 10%, 15%, and 20%, and it was ended with aging heat treatment at a temperature of 300°C and holding time for 1 hour. The novelties of this research are the valid data of corrosion rate and type of TNTZ, which were unavailable before, and corrosion prevention through thermomechanical treatment of TNTZ in Hanks’ solution. The thermomechanical treatment is proved to reduce the pitting corrosion in TNTZ. The results show that thermomechanical treatment and increased plastic deformation can reduce the value of the corrosion rate, as evidenced by the pre-thermomechanical and thermomechanical TNTZ corrosion rates with deformation variations of 10%, 15%, and 20%, respectively, which were 5.522 x 10-4 mmpy; 2.754 x 10-4 mmpy; 2.290 x 10-4 mmpy; and 2.064 x 10-4 mmpy, respectively. TNTZ, after thermomechanical treatment, had the lowest corrosion rate, i.e., 2.064 x 10-4 mmpy, while Ti-6Al-7Nb had the highest one, i.e., 3.05 x10-2 mmpy. The type of TNTZ corrosion is pitting corrosion, as shown by the loss of zirconium that reduced the volume, causing pits to occur. Meanwhile, after thermomechanical treatment, pitting corrosion happened on TNTZ because of the loss or release of zirconium. This research shows that after thermomechanical treatment, TNTZ is the best material compared to other materials for biomedical applications based on corrosion resistance.

Is the Pd Aerogel Assembled by Nanosheets as an Advanced Three-Dimensional Support-less Electrocatalyst in Renewable Energy?

The design and synthesis of efficient electrocatalysts for renewable energy-related processes have emerged as hot topics in the scientific community. This report introduces a valuable and facile way to make a palladium aerogel assembled by nanosheets. A three-dimensional (3D) palladium aerogel is assembled by reducing the palladium(II) acetylacetonate [Pd(acac)2] in the presence of cetyltrimethylammonium bromide and butyric acid, followed by supercritical drying conditions. On the basis of recorded analyses, the expansion and connection of nanosheets generate a beautiful 3D superstructure with a tremendous surface area and large open interconnected pores. The density and thickness of the nanosheets are estimated to be 0.018 g cm–3 and 2.78 nm, respectively. This 3D self-supported advanced electrocatalyst exhibits outstanding efficiency for catalyzing ethanol in direct ethanol fuel cells at 298 K. These exceptional results are due to the fantastic morphology of the aerogel. An inorganic superstructure with open interconnected pores significantly facilitates the accessibility of ethanol molecules to inner active sites. As such, the macroscale nature of the constructed nanoarchitecture will guarantee the interaction of ethanol molecules with the surface of a palladium aerogel. Furthermore, the self-supporting property of the constructed aerogel can help to greatly sustain the durability (relative to the Pd/C) due to the prevention of carbon corrosion.

Microbiologically influenced corrosion of the ST-37 carbon steel tank by Bacillus licheniformis present in biodiesel blends

Microbiologically influenced corrosion (MIC), commonly known as biocorrosion, is a destructive phenomenon that can be initiated by the bioactivities of microbes. It can occur in the diesel mixture storage tank, especially due to the presence of biodiesel, because the biodegradability characteristic of biodiesel results in the enhancement of microbial growth and also the MIC process. The Bacillus genus, such as B. licheniformis, is one of the microbes that is detected in the diesel storage tank and can contribute to MIC pitting phenomena. This study examined biocorrosion in ST-37 carbon steel by B. licheniformis, with variation of biodiesel concentrations (B0, B15, B20, B30, and B100). The results showed that the bioactivity of B. licheniformis increased in all biodiesel concentration cultures compared to the sterile medium. Then the highest corrosion rate was found for samples dipped in the B15-blend. However, the corrosion rate decreased on the specimen immersed in the equal and higher than B20-blend, due to thicker and more uniform biofilm formation. In addition, B. licheniformis can produce γ-polyglutamate, which acts as a corrosion inhibitor. This shows that B. licheniformis-mediated biocorrosion may promote the use of the B100 product as an environmentally friendly biofuel. However, it is important to consider the effects of B. licheniformis on diesel blend medium, especially biodegradation. Furthermore, the study of the production, extraction and implementation of γ-polyglutamate as a green corrosion inhibitor may be very useful in the future as a corrosion prevention solution.

Abrasion and Cavitation Erosion Resistance of Multi-Layer Dip Coated Sol-Gel Coatings on AA2024-T3

AA2024-T3 are widely used in various applications because of their exceptional physical properties. However, they are susceptible to corrosion and cavitation erosion in aggressive environments due to high concentration of copper. Sol-gel coatings in the field of corrosion prevention are emerging. Improved thickness of coatings significantly improves the barrier effect of the coatings, thereby improving their operational-life in industrial applications. To date, a limited amount of work has been carried out in determining the effect of hybrid sol-gel coatings on abrasion and cavitation erosion of AA2024-T3. The present study investigates the effect of thickness of the coatings on morphology, corrosion, abrasion and cavitation erosion properties of the prepared hybrid sol-gel coatings deposited on AA2024-T3 surfaces. The hybrid sol-gels have been synthesized from 3-trimethoxysilylpropylmethacrylate (MAPTMS), and a zirconium complex prepared from the chelation of zirconium n-propoxide (ZPO), and methacrylic acid (MAAH). AA-2024 T3 were coated using single-dip, double-dip and triple-dip. Abrasion and cavitation erosion tests were performed according to the relevant standards. Structural damage caused by corrosion, abrasion and cavitation erosion was studied by Optical Microscope and Scanning Electron Microscope (SEM). Corrosion protection performance of the coatings was tested using Open Circuit Potential (OCP) and Potentiodynamic polarization (PDS). Results indicated that the multilayer coated samples improved the corrosion, cavitation erosion and abrasion resistance of AA2024-T3. Hence, the prepared silica-based coatings can be proposed as a potential choice for marine renewable energy applications.

Mechanical behavior of multi-scale fiber-reinforced concrete for secondary tunnel lining: Field test and numerical simulation

The application of polypropylene fiber in the secondary tunnel lining can provide theoretical guidance for preventing and controlling tunnel lining problems from the perspective of concrete materials. The field tests and long-term observations were carried out to study the inhibitory effect of multi-scale polypropylene fiber-reinforced concrete (MPFRC) on tunnel lining problems and the mechanical characteristics of MPFRC for secondary tunnel lining. The tunnel appearance, concrete lining strength, the contact pressure between the primary and secondary linings and concrete strain were investigated. Besides, the influences of thickness and reinforcement ratio on the stress of MPFRC for secondary tunnel lining under external load were analyzed based on numerical simulation. The results show that: (1) The re-casting of the secondary lining will cause the stress redistribution of the surrounding rock of the primary support. (2) Compared with ordinary concrete, the time-strain curve of MPFRC is flatter and the variation range of the strain value is smaller, with a reduced rate of 45.45 %. (3) MPFRC can reduce the secondary tunnel lining's thickness and hoop reinforcement rate by about 22 % and 25 %, respectively. The research results can provide a reference for the prevention and treatment of lining cracking, water leakage, corrosion and other problems, and provide a theoretical basis for the optimal design of secondary tunnel lining.

Water-Repellent Coatings on Corrosion Resistance by Femtosecond Laser Processing

Metal corrosion causes huge economic losses and major disasters every year. Inspired by the lotus leaf and nepenthes pitcher, the superhydrophobic surfaces (SHS) and the slippery liquid-infused porous surfaces (SLIPS) were produced as a potential strategy to prevent metal corrosion. However, how to prepare stable water-repellent coatings that can prevent the intrusion of corrosive ions remains to investigate. In this work, we first fabricated a micro/nano hierarchical structure on the aluminum surface by femtosecond laser processing. Then, the SHS was prepared on the above structure by fluorosilane modification. Finally, the SLIPS was fabricated on the SHS by coating lubricant. The morphology and wettability of the fabricated samples were evaluated by scanning electron microscopy and contact angle measurements. Furthermore, the corrosion resistance properties of SHS and SLIPS in simulated seawater were characterized by electrochemical measurements. From the comparison of the electrochemical parameters of different immersion times, both water-repellent coatings are effective in protecting the aluminum alloy from corrosion in simulated seawater due to reduced contact area between the metal substrate and corrosive solution. In comparison with the SHS, the SLIPS has a corrosion inhibition efficiency of up to 99.95% and it maintains long-term stability in the corrosive solution. This work also provides a promising method for the water-repellent coatings by femtosecond laser processing for metal corrosion prevention in practical industrial applications.

INHIBTOR KOROSI DARI EKSTRAKSI DAUN TEMBAKAU DENGAN METODE MICROWAVE ASSISTED EXTRACTION (MAE) PADA BERBAGAI LINGKUNGAN

Corrosion is a metal material damage due to environmental interaction and affect to human life. If corrosion not handled well it can cause industry component broken and also cause great environmental damage. Corrosion prevention can be done with adding natural based corrosion inhibitor to corrosion environment. One of natural based material for corrosion inhibitor is tobacco leaf because it contains flavonoid and nitrogen base to inhibit corrosion rate. Tobacco leaf extraction can he done using microwave-assisted extraction (MAE) method that means micro wave base extraction process. This research vary micro wave power, time extraction, rasio feed to solvent and heating temperature to produce tobacco leaf corrosion inhibitor. Implementation of this research can be done by literature study, decide, independent variable, and dependent variable. Independent variables are corrosive environment (HCl 0,5 M; NaOH 1M, and tap water), extraction time (10 menit, 12 menit, 14 menit, 16 menit, dan 18 menit), microwave power (150 Watt dan 300 Watt), and metal plat Fe . Beside that, dependent variable is 60 mesh solid size tobacco leaf that dissolved using ethanol with 0,275 gram sample/mL rasio feed to solvent. This research begins with raw materials and tools preparation, tobacco leaf extraction process, and corrosion inhibitor test. The result results of this research are the biggest efficiency occurred in Sodium Hydroxide environment with corrosion rate 0,09268 mpy and 98,5003& efficiency. Sample test with mayer reagent, wagner reagent, and dragendorf reagent indicate that there is alcoloid exist.

Competitive growth between the top and bottom layers of few-layer graphene at the domain boundary merging stage

Compared with monolayer graphene, few-layer graphene (FLG) also has a broader application prospect in the fields of composite materials, conductive coatings, metal corrosion prevention and electronic devices requiring tunable electronic structures. Herein, FLG is grown on Cu foil by chemical vapor deposition (CVD) and the merging of graphene domain boundary (GDB) network is directly observed by optical microscope (OM). Raman spectra and energy dispersive spectroscopy (EDS) results show that the defect degree of graphene at GDBs is lower than that at domain interior. Raman mapping results indicate that the structure of FLG grown at 980 °C is inhomogeneous and there exist a terraced structure at the GDBs. The atomic force microscopy (AFM) results show that the FLG grown at 980 °C has about ∼7 layers at the GDBs and ∼13 layers at domain interior, respectively. In addition, the Raman spectra results also disclose an unusual phenomenon that graphene at GDBs grown at 980 °C has lower ID/IG ratios than that grown at 1000 °C. A competitive growth mechanism of the top and bottom layers of FLG is proposed to shed light on the synergistic effect of catalysis of Cu and temperature on the late growth stage of FLG.

Choline amino acid ionic liquids as green corrosion inhibitors of mild steel in acidic medium

The corrosion inhibition performance of three choline amino acid ionic liquids ([Ch][AA]ILs) for mild steel in 1 M HCl solution was evaluated by electrochemical analysis, gravimetric measurement, and surface morphological characterization in the temperature range of 298–328 K in this paper. The results of the polarization experiments show that [Ch][AA]ILs affect the cathode and anode reaction processes, proving that [Ch][AA]ILs are mixed corrosion inhibitors. Choline phenylalanine ionic liquids ([Ch][Phe]) exhibit the highest corrosion prevention efficiency among the three chosen corrosion inhibitors, as proven by SEM/EDS scanning, XPS analysis, and molecular dynamics simulation. The values of standard free energy of adsorption ΔGads range between − 20 kJ·mol-1 and − 40 kJ·mol-1, showing that inhibitor molecule adsorption on the metal surface involves both physical and chemical adsorption. According to the results of XPS research and quantum chemical calculations, the adsorption of corrosion inhibitor molecules on the metal surface is strongly related to the anions. The corrosion inhibitor molecules form a thick monolayer adsorption layer on the metal surface, preventing metal-corrosive media interaction. The molecular dynamics simulation findings reveal that the corrosion inhibitor molecules replace the solvent water or any other ions pre-adsorbed on the metal surface during the adsorption process, protecting the metal from corrosion.

An eco-friendly corrosion inhibitor Cuscuta reflexa extract and PEG400 for mild steel inhibition in acidic medium: computational and experimental investigations.

Herein, the mechanism of corrosion prevention of mild steel (MS) by extract of Cuscuta reflexa/Amarbel (AME) as green inhibitor is explained by gravitational, electrochemical measurements. The viability of neat extract and after adding an intensifier was investigated as corrosion inhibitor for MS in hydrochloric acid. The presence of electron-rich moieties in AME was characterized through Fourier-transform infrared spectroscopy (FTIR). Furthermore, polarization measurements showed that AME acted as a mixed type inhibitor against corrosion. The formulation of 100ppm AME with 50ppm polyethylene glycol 400 (PEG400) as an intensifier showed inhibition efficiency of 97.51% for MS in 0.5M HCl. The protection of MS in (AME + PEG) formulation was also assessed through the Langmuir, Freundlich, and Flory-Huggins adsorption isotherm model. The surface studies of the MS were examined by atomic force microscopy (AFM) and scanning electron microscopy (SEM) that indicated a smoothened surface of the metal in the presence of the studied compounds. XPS study was executed to analyze the interaction of the inhibitor with the metal surface. In addition, computational quantum study provides the molecular structural relationship with corrosion inhibitive competence of the extract.

Fabrication of Hierarchical Patterned Surfaces Using a Functionalized CeO2-EPDM Composite for Crevice Corrosion Prevention on High-Voltage Insulators.

Crevice corrosion accounts for 62% of the recorded breakdown of insulators utilized in transmission lines, which may interfere with the reliability of power utilities. To address these challenges, sustainable and resilient slippery lubricant-infused porous surfaces (SLIPS) are developed on insulators to prevent electrochemically/biochemically induced crevice corrosion especially occurring in tropical and coastal environments. The conventional way of developing SLIPS by chemical and physical etching might interfere with the mechanical stability of insulators composed of pin (galvanized steel), cement, and shell (porcelain). The current study proposes a noble concept of developing hierarchical patterned textured surfaces on insulators to fabricate a resilient SLIPS coating without physical/chemical etching. The proposed coating exhibits 99% antiadhesion performance against a mixed culture of bacterial strains, superior hydrophobicity (contact angle: 160°, contact angle hysteresis: 4°), and crevice corrosion resistance performance at elevated temperatures (25-75 °C) and humidity. This study could facilitate a new route for the development of sustainable and highly reliable SLIPS coatings in the future.

The new trends in corrosion control using superhydrophobic surfaces: a review

Abstract Superhydrophobic surface (SHS) fabrication has gained popularity as a corrosion prevention method for metals in recent years. Because of the vast range of sectors that are interested in and using nature-inspired biomimetic SHS, this field of advanced materials science is experiencing rapid growth. Corrosion prevention can be achieved with SHS because it effectively blocks moisture from entering. By generating an air layer between the metal and the coating, SHS provides corrosion prevention. Corrosion-inducing ions are less likely to adhere to metal surfaces with low surface energy and high surface roughness. Combining the right materials and fabrication methods allows you to fine-tune SHS’s many unique features. This review article provides a survey of the superhydrophobic coatings’ performances as metallic protection. Then, various models were utilized to assess the wettability of the rough surface, and the relations governing the contact angle (CA) were reported. Lastly, various methods utilized to prepare the superhydrophobic coatings and their effects on the corrosion processes for metals were also discussed.

STUDY ON DETECTION OF THIN WATER FILM ON STEEL SURFACE USING A HYPERSPECTRAL CAMERA

Steel corrosion is caused by the presence of water. Therefore, it is important to identify the areas where water is supplied, which will lead to efficient corrosion prevention and repair. Previous studies have proposed methods for detecting water on steel, but these studies used attach-type or contact-type measurement devices, making it impossible to detect water in inaccessible locations. The objective of this study is to detect a thin water film on corroded steel using a hyperspectral camera that can acquire visible and near-infrared spectra in a non-contact manner. First, the spectral characteristics of the thin water film detected by the HSC is confirmed by measuring the spectra of water in a petri dish at varying depths. Subsequently, the spectra of corroded steel specimens in dry and wet conditions were measured. As the results, it is indicated that water on steel could be detected by examining the spectra at wavelengths of 435 and 960 nm.

Silver nanoparticles doped poly(3, 4-ethylene dioxythiophene) on titania nanotubes for orthopaedic application

This research is focused on analysing the behaviour of electropolymerized PEDOT doped with AgNPs on TNTA surface (AgNPs-PEDOT/TNTA) to improve corrosion resistance, antibacterial activity and biocompatibility that suits the orthopaedic field of research. Electrochemical anodization was performed to develop a uniformly ordered TNTA in a fluoride-based electrolyte. AgNPs-PEDOT was evenly incorporated on anodized TNTA surface using electropolymerization process. The morphological images of anodized TNTA and AgNPs-PEDOT/TNTA were captured using HR-SEM analysis. XRD, XPS and ATR-FTIR spectroscopic analyses were performed to determine the crystallinity, chemical entities and functional groups of AgNPs-PEDOT/TNTA. The corrosion prevention of AgNPs-PEDOT/TNTA was examined by electrochemical impedance spectroscopy (EIS), scanning electrochemical microscopy (SCEM) and potentiodynamic polarization studies. In vitro immersion studies of AgNPs-PEDOT/TNTA were systematically carried out for 7, 14 and 21 days in Hanks’ solution. The viability and proliferation of MG63 cells with and without silver nanoparticles doped PEDOT were assessed using the MTT assay. The involvement of silver nanoparticles in the antibacterial performance of PEDOT electropolymerized TNTA was examined using gram-positive and gram-negative bacteria. The presence of AgNPs in PEDOT plays a favourable role in long term implantation with excellent antibacterial and biochemical activity.

Effect of Zinc Oxide Concentrations on Anodic Coated AZ91D Mg Alloy for Surface Modification Applications

The AZ91D Magnesium (Mg) Alloy is broadly known as an attractive material with many applications ranging from military goods and aerospace to automobile applications due to its excellent properties in lightweight, machinability, and castability. Unfortunately, Mg Alloys are also prone to corrosion resulting in degradation of the components, which can lead to severe component failure and injuries. Thus, corrosion prevention is required for the AZ91D Mg alloy to increase its performance in the environment. This paper uses the anodising method to study the influence of Zinc Nitrate’s electrolyte concentrations on anodic coated AZ91D Mg Alloys. This method formed a thin film layer on the AZ91D Mg Alloy’s samples known as an anodic film, which can potentially reduce the corrosion activity on the surface of the substrate. To investigate the corrosion activity of the anodised samples, the corrosion rate value was calculated by immersion of coated samples in a salt solution. The coated and corroded surfaces' morphology, structure, and thickness are observed using a Scanning Electron Microscope (SEM). At the same time, the element content of the material will be determined using X-ray diffraction (XRD). Thus, the resulting influence of Zinc Nitrate electrolyte concentration by anodising method shows which concentration value successfully formed the best Zinc Oxide (ZnO) coating layer on AZ91D Mg Alloy samples. Furthermore, an anodisation method using suitable concentrations of Zinc Nitrate electrolyte can be further developed to form an appropriate surface treatment for automotive applications in resisting corrosion in its environment.

Poly Acrylic-Chitosan Co-Polymer as Corrosion Inhibitor for Mild Steel in 0.5 M Hydrochloric Acid Solutions

Corrosion prevention has been one of the major concerns these days various methods have been adopted for corrosion prevention. However, the use of corrosion inhibitors has proven to be the easiest and cheapest method for corrosion prevention. But then most of the conventional inhibitors are expensive and toxic. Therefore the recent focus has been turned to developing non-toxic and cheap corrosion inhibitors. To achieve that a Polyacrylic acid was successfully grafted on chitosan by the thermal method using a reflux condenser. This copolymer was characterized by FTIR, TGA, and XPS. The corrosion inhibition performance of the grafted polymer was tested on mild steel in 0.5 M HCl under different conditions by gravimetric method. Mild steel coupon was analyzed using SEM to understand the effect of the inhibitor on the mild steel corrosion. The results were subjected to various adsorption isotherm models to understand the corrosion mechanism. The weight loss results show high inhibition efficiency of 86.50432 % for 24 hrs. Immersion time at 300 °C conditions. Data best fitted with Langmuir adsorption model with a good correlation coefficient of 0.9933.

Chitosan coating fabricated through nanotopography and alkylation for the prevention of bacterial attachment and corrosion

Although metallic materials are widely used in biomedical devices, most of them have no antibacterial property and exhibit corrosion-related problems in physiological environments. This study aimed to develop a biocide-free chitosan coating to inhibit bacterial adhesion and corrosion. First, a chitosan coating fabricated through nanotopography was formed on the surface of carbon steel by using soft imprinting technology. Next, hexanal was grafted onto the chitosan by using a Schiff base reaction. Nanomorphological assessments using scanning electron microscopy, confocal laser scanning microscopy, and cross-sectional transmission electron microscopy confirmed a concave width, depth, and bottom thickness of approximately 666, 242, and 208 nm, respectively. Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy confirmed that hexanal was successfully grafted to chitosan. Finally, the surface hydrophobic properties, antibacterial adhesion, and electrochemical corrosion resistance of chitosan coatings with and without nanopatterning and hexanal grafting were investigated. The results indicated that the hydrophobic angle of chitosan with both nanopatterning and hexanal grafting exceeded 120° and that the hysteresis angle was only 20°, which may help inhibit the attachment of Staphylococcus aureus and Escherichia coli. During an electrochemical corrosion test, chitosan with both nanopatterning and hexanal grafting exhibited the highest corrosion potential and the lowest corrosion current density, indicating improved corrosion resistance. These results suggest that imparting nanopatterning and alkylation properties to chitosan solves not only the problem of bacterial attachment to bare metal substrates but also the problem of corrosion.

Designing a Ti3C2Tx MXene with long-term antioxidant stability for high-performance anti-corrosion coatings

Two-dimensional titanium carbide (Ti3C2Tx) MXene has many distinctive advantages, including high conductivity, energy-storing, catalysis, etc. In particular, its accordion-like lamellar structure could provide excellent barrier properties to corrosive agents, which exhibit potential application value for anti-corrosion coatings. However, the problem that MXenes are susceptible to oxidative degradation in an aggressive environment limits its further application in the field of corrosion prevention. Herein, in our work for the first time, an effective method was developed for protecting sensitive Ti3C2Tx MXene against oxidation by imidazolium salt modification (I-Ti3C2Tx), which considerably increased MXene antioxidant stability. The crystalline structure of I-Ti3C2Tx remained unaltered in an aqueous solution for 30 days and kept the lamellar structure for a long period. Simultaneously, 1.0 wt% I-Ti3C2Tx/EP could provide excellent anti-corrosion protection. A new synergistic mechanism for improving antioxidant stability and anti-corrosion property of I-Ti3C2Tx/EP coatings was developed and clarified based on the free radical scavenging ability of imidazolium ions and the chemical characteristics of MXene.

Enhancement of the corrosion resistance of mild steel with femtosecond laser- nanostructuring and CrCoNi medium entropy alloy coating

In this work, the corrosion resistance of mild steel surface nanostructured with a femtosecond laser and coated with high corrosion resistant CrCoNi (CCN) medium entropy alloy through magnetron sputtering is studied. Substantial improvement in corrosion protection was achieved by applying a combination of high-power femtosecond laser surface nano-structuring at ambient conditions and thin-film coating with (CCN) medium entropy alloy. XRD analysis revealed that femtosecond laser structuring increases the susceptibility of the surfaces to Fe2O3 nucleation through oxidation. The surface wettability measurements and electrochemical polarization tests revealed that the combined approach of femtosecond laser structuring and magnetron sputter coating is the best for desired high corrosion resistance. Through this novel method, the resulting corrosion resistance of mild steel was improved by more than one-fold. The results are explained considering the detailed microstructural analysis. The presented findings open new possibilities for corrosion prevention using a combination of new powerful technologies that yield to unprecedented corrosion-inhibition efficacy.