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Single-layer isophorone diisocyanate (IPDI) are one of the most popular self-healing microcapsules but suffers from low shell strength, poor heat resistance, stability and aging properties. In this paper, IPDI microcapsules were encapsulated into double-layer phenolic (PF)/polyurethane (PU) by a two-step process involving interfacial polymerization and in-situ polymerization. The prepared microcapsule composites were comprehensively characterized for their physical and chemical properties using optical microanalysis, scanning electron microscope, Fourier transform infrared spectroscopy, thermal gravimetric analysis and depth-sensing indentation analysis. Compared with the single-layer PU-IPDI microcapsule counterpart, the mechanical performance, thermal resistance, aging property and environmental stability of double-layer PF/PU-IPDI microcapsules were significantly improved. The epoxy coating was enhanced with the incorporation of 10 wt.% PF/PU-IPDI microcapsules, whose self-healing performance was evaluated by scratch corrosion test. The results demonstrated successful repair of coating scratches, along with the absence of corrosion on the coated steel substrate soaked in a 10 wt.% NaCl solution for 7 days. By comparing the tensile strength of epoxy coating before and after crack formation, it could be found that the self-healing efficiency was 57.9% when loaded with 10 wt.% of PF/PU-IPDI microcapsules in coating. This study highlights that the rational design of double-layer microcapsules integrated into the epoxy coating matrix could provide excellent anti-corrosion and self-healing properties.

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The pursuit of carbon-neutral energy has intensified the interest in green hydrogen production from direct seawater electrolysis, given the scarcity of freshwater resources. While Ni-based catalysts are known for their robust activity in alkaline water oxidation, their catalytic sites are prone to rapid degradation in the chlorine-rich environments of seawater, leading to limited operation time. Herein, we report a Ni(OH)2 catalyst interfaced with laser-ablated LiFePO4 (Ni(OH)2/L-LFP), derived from spent Li-ion batteries (LIBs), as an effective and stable electrocatalyst for direct seawater oxidation. Our comprehensive analyses reveal that the PO43- species, formed around L-LFP, effectively repels Cl- ions during seawater oxidation, mitigating corrosion. Simultaneously, the interface between in situ generated NiOOH and Fe3(PO4)2 enhances OH- adsorption and electron transfer during the oxygen evolution reaction. This synergistic effect leads to a low overpotential of 237 mV to attain a current density of 10 mA cm-2 and remarkable durability, with only a 3.3 % activity loss after 600 h at 100 mA cm-2 in alkaline seawater. Our findings present a viable strategy for repurposing spent LIBs into high-performance catalysts for sustainable seawater electrolysis, contributing to the advancement of green hydrogen production technologies.

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The conducted research focused on anti-corrosion systems applied for the protection of structural parts used in public transport vehicles. Detailed tests were carried out on samples taken from the brackets supporting the doors of a public transport bus. This work includes the results of the chemical analysis of the composition of snow-mud samples taken from the selected bus route and the results of laboratory tests performed on samples with various anti-corrosion coatings. Four types of samples made of S235JR steel with a zinc coating deposited by thermo-diffusion, electroplating, hot-dip zinc galvanization, and the cataphoresis method were tested. Both non-destructive tests-NDTs (the measurement of coating thickness and roughness, microscopic observations)-and destructive tests-DTs (scratch tests, salt chamber tests)-were performed. The conducted tests proved that the most effective method is the use of anti-corrosive hot-dip zinc coating.

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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 (<20 nm) 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.

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Plant-mediated synthesis of silver nanoparticles (AgNPs) is an eco-friendly and convenient alternative to conventional methods. Brassaiopsis hainla (B. hainla) leaf extract (BHE) was used in this study to reduce metal salts and cap and stabilize nanoparticles (NPs), which were characterized and tested for antibacterial and anti-corrosion properties. Stirring the B. hainla extract with AgNO3 led to a color change, indicating nanoparticle formation. The absorption peak at 428 nm in the UV-visible spectrum further validated its formation. The AgNPs were characterized using various techniques such as FTIR, UV-visible, PXRD, HRTEM, SEM, and EDX. Powder X-ray diffraction analysis confirmed its nanocrystalline nature, with an average crystallite size of 17.92 nm. The FTIR spectrum showed hydroxyl, amine, amide, and carbonyl groups as capping and reducing agents for the AgNPs. SEM analysis revealed poly-dispersed NPs of various sizes, while EDX showed an intense peak for Ag, and TEM images revealed mostly hexagonal and triangular NPs. Antibacterial activity was tested against three human pathogens: Staphylococcus aureus (S. aureus), Pseudomonas, and Klebsiella oxytoca (K. oxytoca). Significant antibacterial activity was observed specifically against K. oxytoca, with an 11 mm inhibition zone. Both plant extracts and AgNPs inhibited acid-induced corrosion, with the highest inhibition efficiencies of 81.69 % and 69.54 % at 1000 ppm, respectively. With rising concerns over bacterial resistance and metal corrosion, this study addresses global challenges related to new antimicrobial agents, which are crucial for combating antibiotic resistance and protecting metals in various industries.

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The corrosion protection of tool steel surfaces is of significant importance for ensuring cutting precision and cost savings. However, conventional surface protection measures usually rely on toxic organic solvents, posing threats to the environment and human health. In this regard, an integrated process of laser texturing and electrostatic flocking is introduced as a green anti-corrosion method on a high-speed steel (HSS) surface. Drawing from the principles of textured surface energy barrier reduction and fiber array capillary water evaporation enhancement, a flocking surface with a synergistic optimization of surface wettability and evaporation performance was achieved. Then, contact corrosion tests using 0.1 mol/L of NaCl droplets were performed. Contact angles representing wettability and change in droplet mass representing evaporation properties were collected. The elements and chemical bonds presented on the corroded surfaces were characterized by X-ray photoelectron spectroscopy (XPS). The results revealed that the flocking surface exhibited the lowest degree of corrosion when compared with smooth and textured surfaces. Corrosion resistance of the flocking surface was achieved through the rapid spread and evaporation of droplets, which reduced the reaction time and mitigated electrochemical corrosion. This innovative flocking surface holds promise as an effective treatment in anti-corrosion strategies for cutting tools.

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Improving the electrical performance of copper, the most widely used electrical conductor in the world is of vital importance to the progress of key technologies, including electric vehicles, portable devices, renewable energy, and power grids. Copper-graphene composite (CGC) stands out as the most promising candidate for high-performance electrical conductor applications. This can be attributed to the superior properties of graphene fillers embedded in CGC, including excellent electrical and thermal conductivity, corrosion resistance, and high mechanical strength. This review highlights the recent progress of CGC conductors, including their fabrication processes, electrical performances, mechanisms of copper-graphene interplay, and potential applications.

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This paper presents the methodology developed for underwater measurements using electrochemical impedance spectroscopy (EIS) technique, aimed at determining the resistance of an epoxy coating applied in seawater to the legs of an oil production platform. Performing such underwater tests in an offshore environment was technically challenging. The results of measurements obtained on the platform were confronted with comparative results obtained in the laboratory, where the properties of the coating applied in water collected from the Baltic Sea (thickness, hardness, adhesion, and electrical resistance) were examined. This made it possible to conclude about the correctness of the paint coating application by divers on the legs of the platform. The single-layer epoxy coating applied by brush to the platform legs had a resistance above 10 kΩ∙cm2 and thus met the assumed minimum resistance of the protective coating cooperating with cathodic protection as the anti-corrosion protection system of the platform legs. The synergy of these two technologies ensures full protection of offshore structures against corrosion. Measurements of the potential of the platform legs confirmed this. Before painting, the potential value at a depth of 0-15 m was 310 ÷ 320 mV versus the zinc reference electrode, while after painting the potential value decreased to 220 ÷ 240 mV, which means that the effect of full cathodic protection was achieved and the platform legs were protected from corrosion. The developed methodology for underwater EIS measurements on the high seas can be applied to any underwater metal structure to assess the quality of protective coatings.

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Epoxy resins were reinforced with different ZnO nanofillers (commercial ZnO nanoparticles (ZnO NPs), recycled ZnO and functionalized ZnO NPs) in order to obtain ZnO-epoxy composites with suitable mechanical properties, high adhesion strength, and good resistance to corrosion. The final properties of ZnO-epoxy composites depend on several factors, such as the type and contents of nanofillers, the epoxy resin type, curing agent, and preparation methods. This paper aims to review the preparation methods, mechanical and anti-corrosion performance, and applications of ZnO-epoxy composites. The epoxy-ZnO composites are demonstrated to be valuable materials for a wide range of applications, including the development of anti-corrosion and UV-protective coatings, for adhesives and the chemical industry, or for use in building materials or electronics.

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Reinforced concrete structures are prone to the corrosion of steel bars when exposed to chloride-rich environments, which can severely impact their durability. To address this issue, a comprehensive understanding of the factors influencing chloride ion diffusion in concrete is essential. This paper provides a summary of recent domestic and foreign research on chloride ion transport in concrete, focusing on six key factors: water-binder ratio, additive content, crack width, ambient temperature, relative humidity, and dry-wet cycles. The findings show that the diffusion coefficient of chloride ions in concrete increases with a higher water-binder ratio and decreases with increased additive content. Additionally, wider cracks result in a greater diffusion of chloride ions. The permeability resistance of concrete to chloride ions decreases with rising temperature and humidity, and dry-wet cycles further accelerate the diffusion of chloride ions. The article concludes by discussing various anti-corrosion measures, such as the use of corrosion inhibitors, surface coatings, and electrochemical treatments, to ensure the longevity of the structure. Finally, directions for future research are proposed.

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Researchers face significant challenges because of the inadequate corrosion resistance and weak adherence of epoxy (EP) coatings. We deal with these issues here by means of a novel nano-composite coating (EP/nano-CoS2). In order to create a composite coating (EP/nano-CoS2), CoS2 nanoparticles (nano-CoS2) were prepared and incorporated to an epoxy (EP) resin. The synthesized CoS2 was characterized using XRD and FT-IR spectroscopic techniques. The mean particle size was determined using Scherer equation and found to be 19.38 nm. The zeta potential was also determined (- 9.78 mV). Electrochemical impedance spectroscopies (EIS) as well as pull-off assessments were used to quantify the EP/nano-CoS2 coating's anti-corrosion capabilities and adhesive power. The findings demonstrate that the EIS variables of the EP/nano-CoS2 composite coating are markedly improved when compared to raw EP coating. The corrosion resistance or even adhesion of EP protective layer can be markedly increased by using the synthesized nanoparticles as nano-fillers.

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In this study, a series of amine-modified mesoporous silica (AMS)-based epoxy composites with superhydrophobic biomimetic structure surface of Xanthosoma sagittifolium leaves (XSLs) were prepared and applied as anti-corrosion and anti-biofilm coatings. Initially, the AMS was synthesized by the base-catalyzed sol-gel reaction of tetraethoxysilane (TEOS) and triethoxysilane (APTES) through a non-surfactant templating route. Subsequently, a series of AMS-based epoxy composites were prepared by performing the ring-opening polymerization of DGEBA with T-403 in the presence of AMS spheres, followed by characterization through FTIR, TEM, and CA. Furthermore, a nano-casting technique with polydimethylsiloxane (PDMS) as the soft template was utilized to transfer the surface pattern of natural XSLs to AMS-based epoxy composites, leading to the formation of AMS-based epoxy composites with biomimetic structure. From a hydrophilic CA of 69°, the surface of non-biomimetic epoxy significantly increased to 152° upon introducing XSL surface structure to the AMS-based epoxy composites. Based on the standard electrochemical anti-corrosion and anti-biofilm measurements, the superhydrophobic BEAMS3 composite was found to exhibit a remarkable anti-corrosion efficiency of ~99% and antimicrobial efficacy of 82% as compared to that of hydrophilic epoxy coatings.

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Recently, the scientific community's main goal is the long-term sustainability. Vegetable oils are easily accessible, non-depletable, and cost-effective materials. Vegetable oils are used to prepare polymeric alkyd surfaces. Novel and exciting designs of alkyd/graphene nanocomposites have provided eco-friendly thermal stability and protective coating surfaces. This review has briefly described important graphene-based alkyd nanocomposites along with their applications as protective coatings. These alkyd composites have high hydrophobicity, corrosion resistance, and durability. Graphene-based alkyd nanocoatings have many industrial and research interests because of their exceptional thermal and chemical properties. This work introduces an advanced horizon for developing protective nanocomposite coatings. The anti-corrosion properties and coatings' longevity may be improved by combining the synergistic effects of hybrid nanofillers introduced in this work.

Asunto(s)

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4,6-Bis(3,5-dimethyl-1H-pyrazol-1-yl)-N-phenyl-1,3,5-triazin-2-amine (PTA-1), N-(4-bromophenyl)-4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazin-2-amine (PTA-2) and 4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-N-(4-methoxyphenyl)-1,3,5-triazin-2-amine (PTA-3) were synthesized and characterized. Their corrosion inhibition of carbon C-steel in 0.25 M H2SO4 was studied by electrochemical impedance. The inhibition efficiency (IE%) of triazine was superior due to the cumulative inhibition of triazine core structure and pyrazole motif. Potentiodynamic polarizations suggested that s-triazine derivatives behave as mixed type inhibitors. The IE% values were 96.5% and 93.4% at 120 ppm for inhibitor PTA-2 and PTA-3 bearing -Br and -OCH3 groups on aniline, respectively. While PTA-1 without an electron donating group showed only 79.0% inhibition at 175 ppm. The adsorption of triazine derivatives followed Langmuir and Frumkin models. The values of adsorption equilibrium constant K°ads and free energy change ΔG°ads revealed that adsorption of inhibitor onto steel surface was favoured. A corrosion inhibition mechanism was proposed suggesting the presence of physical and chemical interactions. Density functional theory computational investigation corroborated nicely with the experimental results. Monte Carlo simulation revealed that the energy associated with the metal/adsorbate arrangement dE ads/dN i, for both forms of PTA-2 and PTA-3 with electron donating groups (-439.73 and -436.62 kcal mol-1) is higher than that of PTA-1 molecule (-428.73 kcal mol-1). This aligned with experimental inhibition efficiency results.

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The influence of polymer emulsion, pigment filler, and dispersant on the corrosion resistance of polymer cement-based composite anti-corrosion coatings were investigated in this study. Adhesion loss rate tests and electrochemical tests were conducted on samples. The research results show that optimal corrosion resistance can be achieved with a 45 wt% dosage of emulsion, a 6 wt% dosage of pigment filler, and a 0.30 wt% dosage of dispersant. The bonding properties of bare steel bars, epoxy-coated steel bars, and polymer cement-based composite anti-corrosion coated steel bars with grout were compared. The results show that the polymer cement-based composite anti-corrosion coating can enhance the bonding properties of the samples. Furthermore, the microscopic analysis was conducted on the samples. The results demonstrate that the appropriate addition of emulsion can fill internal pores of the coating, tightly bonding hydration products with unhydrated cement particles. Moreover, incorporating a suitable dosage of functional additives enhances the stability of the coating system and leads to a denser microstructure.

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Under damp or aquatic conditions, the corrosion products deposited on micro-cracks/pore sites bring about the failure of intrinsically healable organic coatings. Inspired by mussels, a composite coating of poly (methyl methacrylate-co-butyl acylate-co-dopamine acrylamide)/phenylalanine-functionalized boron nitride (PMBD/BN-Phe) is successfully prepared on the reinforcing steel, which exhibits excellent anti-corrosion and underwater self-healing capabilities. The self-healing property of PMBD is derived from the synergistic effect of hydrogen bonding and metal-ligand coordination bonding, and thereby the continuous generation of corrosion products can be significantly suppressed through in situ capture of cations by the catechol group. Furthermore, the corrosion protection ability can be remarkably improved by the labyrinth effect of BN and the inhibition role of Phe, and the desired interfacial compatibility can be formed by the hydrogen bonds between BN-Phe and PMBD matrix. The corrosion current density (icorr) of PMBD/BN-Phe coating is determined as 7.95 × 10-11 A cm-2. The low-frequency impedance modulus (|Z|f  =  0.0 1 Hz is remained at 3.47 × 109 Ω cm2, indicating an ultra-high self-healing efficiency (≈89.5%). It is anticipated to provide a unique strategy for development of an underwater self-healing coating and robust durability for application in anti-corrosion engineering of marine buildings.

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The exceptional corrosion resistance and combined physical and chemical self-cleaning capabilities of superhydrophobic photocatalytic coatings have sparked significant interest among researchers. In this paper, we propose an economical and eco-friendly superhydrophobic epoxy resin coating that incorporates SiO2@CuO/HDTMS nanoparticles modified with Hexadecyltrimethoxysilane (HDTMS). The application of superhydrophobic coatings effectively reduces the contact area between the metal surface and corrosive media, leading to a decreased corrosion rate. Additionally, the incorporation of nanomaterials, exemplified by SiO2@CuO core-shell nanoparticles, improves the adhesion and durability of the coatings on aluminum alloy substrates. Experimental data from Tafel curve analysis and electrochemical impedance spectroscopy (EIS) confirm the superior corrosion resistance of the superhydrophobic modified aluminum alloy surface compared to untreated surfaces. Estimations indicate a significant reduction in corrosion rate after superhydrophobic treatment. Furthermore, an optical absorption spectra analysis of the core-shell nanoparticles demonstrates their suitability for photocatalytic applications, showcasing their potential contribution to enhancing the overall performance of the coated surfaces. This research underscores the promising approach of combining superhydrophobic properties with photocatalytic capabilities to develop advanced surface modification techniques for enhanced corrosion resistance and functional properties in diverse industrial settings.

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In this study, the efficacy of the combined effect of borate and silicate alkali metal salts added to mortars for controlling the chloride-induced uniform and localized corrosion of embedded steel rebars is examined. The individually added salts in mortars are found to have insignificant effects in terms of reducing the uniform corrosion rate and localized damage. However, their combination (0.50% sodium tetra borate + 0.10% sodium silicate added with respect to the weight of the binder) provides complete protection to reinforcements tested for long durations under wet/dry treatments with mortars in saline water and laboratory atmospheres. Electrochemical impedance spectroscopy, direct current cyclic polarization, polarization resistance, and visual observations are used for quantitative and qualitative evaluations of the protective effects of the tested additives. X-ray diffraction analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis of the corrosion products formed on the embedded steel surfaces help explain the possible mechanisms behind the considerable improvement in the inhibitive effects of a mixed composition of borate and silicate. This combination also improves the compressive strength and workability of the mixed concrete. The results reveal that the synergistic protection provided by a mixture of borate and silicate can be attributed to the co-deposition of an iron-boron + ferrosilicate + cortensitite (an iron-silicon phase) film on the rebar surface.

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Waterborne epoxy (WEP) coatings with enhanced corrosion resistance were prepared using graphene oxide (GO) that was obtained from kish graphite, and amino-functionalized graphene oxide (AGO) was modified by 2-aminomalonamide. The structural characteristics of the GO and AGO were analyzed using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). And the anti-corrosive performance of waterborne epoxy-cased composite coatings with different addition amounts of AGO was investigated using electrochemical measurements, pull-off adhesion tests, and salt spray tests. The results indicate that AGO15/WEP with 0.15 wt.% of AGO has the best anti-corrosive performance, and the lowest frequency impedance modulus increased from 1.03 × 108 to 1.63 × 1010 ohm·cm-2 compared to that of WEP. Furthermore, AGO15/WEP also demonstrates the minimal corrosion products or bubbles in the salt spray test for 200 h, affirming its exceptional long-term corrosion protection capability.

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In this research, a self-healing nano-coating with excellent photo-thermal response to near-infrared (NIR) laser is prepared. This coating incorporates silver sulfide anchored bismuth molybdate (Ag2S@Bi2MoO6) into a shape memory epoxy resin to achieve for a good photo-thermal conversion capability. The Ag2S@Bi2MoO6 p-n heterojunction could photo-generate more electron-holes pairs under the NIR laser irradiation. Also, it shows a wider absorption range of visible light, leading to effectively absorb the light energy, generate enough heat to induce the shape memory recovery in the coating, and seal the scratch. The results indicate that the temperature of EP-1 % Ag2S@Bi2MoO6 coating has reached about 88 °C, while good self-healing and anti-corrosion properties with a self-healing rate of 88.41 % have been achieved. Furthermore, calculations based on Density Functional Theory and Finite Element Method pointed out that the formation of p-n heterojunction effectively has enhanced the photo-thermal effect. This research opens a new way for developing self-healing coatings with an ultra-fast response time and high self-healing efficiency.