Excellent Anti-corrosion Performance Research Articles

Superhydrophobic concrete coating with excellent mechanical robustness and anti-corrosion performances

In this study, an environmentally friendly superhydrophobic surface for concrete (S-concrete) with excellent mechanical robustness and anti-corrosion performances was put forward. By introducing geopolymer material, a novel inorganic gelling material act as binders to enhance the stability of the S-concrete, the suspension based on stearic acid (STA) modified by micro diatomaceous earth (DE) and nano alumina (Al2O3) were intensely attached to the substrate. The structure morphologies, chemical compositions, surface wetting behavior of this S-concrete were systematically investigated by SEM, XRD, FT-IR and wettability measurements. The results showed that the S-concrete coating was successfully constructed by achieving a desirable static contact angle of 159.1° and a small slide angle 4.5°. The S-concrete features Cassie-Baxter phase contacts, liquids repellency, anti-fouling and self-cleaning properties. The S-concrete exhibited excellent resistance to chloride corrosion, which was reduced by about 2 orders of magnitude compared to ordinary concrete. What is more, this S-concrete coating showed remarkable robustness against sandpaper abrasion and tape-peeling, while retaining its superhydrophobicity even suffering 200 abrasion cycles and 60 tape-peeling. The improved durable mechanical robustness and interfacial bonding force can be attributed to the cross-linked three-dimensional hierarchical structures formed by the combination of geopolymer material and embedded DE/Al2O3@STA micro-nanoparticles.

Polypyrrole/NiFe-layered double hydroxide composite as an anticorrosive microwave absorber

Polypyrrole/NiFe-layered double hydroxide composite with excellent microwave absorption capability and anti-corrosion performance that can be used in marine environments.

Triboelectric nanogenerators with groove textures and carbon fillers for self-powered cathodic protection.

Contact-separation mode triboelectric nanogenerators (CS-TENG) have received widespread attention in self-powered cathodic corrosion protection, but their relatively low output limits the application. This paper introduced both groove textures and carbon-fillers into CS-TENG and investigated the influences and mechanism of textures and filler parameters on the output of CS-TENG. Through the external connection to the protected metal, the CS-TENG with optimal textures and fillers established the power supply of the self-powered cathodic protection. It is shown that for CS-TENG with groove textures, a texture size of 10 μm-10 μm exhibits the maximum lateral deformation, which generates the largest contact area and lateral deformation, and thus outputs the highest voltage. Among the three selected carbon-fillers (carbon fibers, hard carbon particles, graphene oxide), carbon fibers with 0.5 wt% mass fraction provide the highest charge storage capacity and thus the largest electrical output. Compared to the CS-TENG without textures and fillers, the open-circuit voltage of CS-TENG with optimal textures and fillers increased by 165.08%. Cathode anti-corrosion experiments and EIS (electrochemical impedance spectroscopy) tests indicate that CS-TENG with optimal textures and fillers significantly reduce the electron transfer rate on the metal surface, exhibiting excellent anti-corrosion performance.

Design of a smart protective coating with molybdate-loaded halloysite nanotubes towards corrosion protection in reinforced concrete

Using protective coatings is widely acknowledged as an effective strategy for preventing the corrosion of reinforcing steel and improving the durability of reinforced concrete structures. Nevertheless, a common challenge faced by the traditional coatings lies in the significantly reduced corrosion resistance due to its damage and cracking during the service life. Accordingly, a smart protective coating with active anti-corrosion performance was successfully designed and synthesised in this study, including a PA-polyvinyl alcohol (PVA) pretreatment layer and the molybdate-loaded etched halloysite nanotube (EHNT@MO). The PA-PVA grafting solution could fix EHNT@MO on the steel surface due to its strong chelating ability, resulting in an increased thickness of the pretreatment layer (∼5 μm) and exceptional barrier properties. Moreover, the release of molybdate from EHNT enables the smart protective coating to actively repair corrosion pits, thereby exhibiting excellent anti-corrosion performance. As a newly developed smart protective coating, it is expected to confer multifunctional properties to reinforcing steel in cementitious materials when subjected to aggressive environments.

A double-layer multifunctional superhydrophobic coating with excellent anti-corrosion performance based on fluorine-free chemicals

Superhydrophobic coatings with micro and nano structures have great potential in a wide spectrum of fields due to their multifunctionality. However, some disadvantages, such as poor wear resistance and containing toxic fluorine substances, greatly limit the practical application of superhydrophobic coatings. To overcome these shortcomings, herein we have prepared a double-layer coating without fluorine which demonstrates superhydrophobicity with a contact angle of 159.5°. The bottom layer of KH560-graphene oxide (GO)/epoxy (EP) and the surface layer of hydrophobic hexadecyltrimethoxysilane modified SiO2 (HDTMS-SiO2) is prepared by scraping and spraying, respectively. The bottom layer of KH560-GO/EP effectively promotes the adhesion of the top SiO2 layer and the coating maintains a superhydrophobic state even after sandpaper sanding, compressive studies and sand impact. In addition, the coating also has superior self-cleaning, anti-fouling, and anti-icing abilities, and it takes 157 s for it to ice up. More importantly, the superhydrophobic coating also exhibits outstanding corrosion resistance due to the synergistic effect of well-dispersed GO and hydrophobic surfaces. This work has demonstrated the great potential of fabricating composite superhydrophobic coatings via artificial architecture design for diversified applications.

Superhydrophobic and corrosion-resistant of 2-methylimidazolezincsalt-based coating enhanced with silane modification

Developing eco-friendly coatings is crucial for protecting the surface of carbon steel, and particularly important is the development of chemically stable, durable, and highly stable superhydrophobic coatings which have become a growing trend. In this study, a hydrophobic nano-composite coating was synthesized, which consists of 2-methylimidazolezincsalt (ZIF-8) particles stabilized in cross-linked TEOS and coated with micro/nano-sized silica. Electrochemical experiments and surface analysis were conducted to evaluate the electrochemical behavior and interaction mechanism between ZIF-8 @SiO2/APTES/EP and Fe. The results showed that ZIF-8 @SiO2/APTES/EP has excellent inhibition performance in 3.5 wt% NaCl solution with inhibition efficiency up to 99.99%. Even after soaking for 72 h, the impedance modulus remains at 6 orders of magnitude, demonstrating excellent anti-corrosion performance. SEM and contact angle analysis demonstrated that a dense ZIF-8 @SiO2/APTES/EP film was formed on the mild steel surface, which has good corrosion resistance and chemical stability. This study is of great significance for guiding the design of high-performance hydrophobic coatings and meets the requirements of various industries for corrosion protection of mild steel surfaces.

Effect of partial substitution of Cr with Co on the properties of Fe35Ni20Cr20-xCoxMo5P12C4B4 high-entropy bulk metallic glasses

Novel Fe35Ni20Cr20-xCoxMo5P12C4B4 (x = 0, 4,8, 12, 16 in at.%, denoted as Cr20-xCoxMo5) high-entropy bulk metallic glasses (HE-BMGs) with excellent comprehensive performance were successfully fabricated using Fluxing and J-quenching methods. The focus was on studying the influences of different Co content on the glass-forming ability (GFA), mechanical performances, magnetic properties, and anti-corrosion performance. It was found that adding an appropriate amount of Co to replace Cr in Cr20-xCoxMo5 alloys can improve GFA. The Cr12Co8Mo5 specimen displays the maximum critical diameter of 3.5 mm and maximum super-cooled liquid phase of 51 K. The compression tests show that the plasticity was enhanced from 0.2 % for the Co-free alloy to 2.5 % for the 12 at.% Co-added alloy. The saturation magnetization (Js) of Cr20-xCoxMo5 alloys gradually increased from 0.04 to 0.68 T with the increase of Co. Electrochemical tests indicate that in 3.5 wt.% NaCl solution at room-temperature (RT), the anti-corrosion performance of Cr20-xCoxMo5 alloys expresses a trend of first increasing and then decreasing with the increase of Co, and all samples show a remarkably higher anti-corrosion performance than 316 L and 304 L stainless steel. The Cr16Co4Mo5 sample exhibits the highest anti-corrosion performance with the self-corrosion current density (Icorr) and the self-corrosion potential (Ecorr) are 9.5 × 10−9 A/cm2 and -0.270 V, respectively. The X-ray photoelectron spectroscopy (XPS) analysis of the Cr16Co4Mo5 shows that there is a higher content of metal kation oxides of Fe2+, Cr3+ and Mo4+ in the passive films compared to Cr20Mo5 and Cr4Co16Mo5. It is indicated that the Cr16Co4Mo5 specimen has the optimal corrosion resistance in this current research. The present HE-BMGs have high GFA, high plastic strain,and excellent anti-corrosion performance, which have potential application value in the engineering field.

A novel fabrication method of slippery lubricant-infused porous surface by thiol-ene click chemistry reaction for anti-fouling and anti-corrosion applications

Abstract A novel and simple way for efficiently preparing stable and non-toxic slippery lubricant-infused porous surface (SLIPS) will expand its anti-fouling and anti-corrosion applications in marine environments. Herein, vinyl-terminated polydimethylsiloxane was covalently grafted on the surface of nano-SiO2 by a thiol-ene click chemistry reaction. After that, SLIPS was efficiently prepared at room temperature via the spraying method on various substrate surfaces. Surface wettability results showed that a water droplet (10 μL) can slip on the surface with an inclination of 10° and a stained water droplet can slip without stain during the slide process, which proved that SLIPS displayed excellent slippery performance. The existence of molecular-level slippery silicone oil film on the rough surface. Anti-fouling and anti-corrosion tests showed that the prepared SLIPS exhibited stable and excellent anti-fouling and anti-corrosion performance after immersion in Pseudoalteromonas sp. culture solution for 14 days. The SLIPS exhibited a value of more than 98% of bacterial attachment inhibition efficiency and a value of 99.9% of corrosion inhibition efficiency. This facile method provides guidance to fabricate SLIPS for its anti-fouling and anti-corrosion applications in marine environments.

A smart acid-responsive GO/MS/BTA hybrid epoxy-based anti-corrosion coating for Mg alloy

Conventional surface coatings exhibit poor self-healing ability, especially under the acid corrosion conditions, which is regarded as a huge challenge for the effective protection of Mg alloy. In this study, a smart self-healing hybrid coating is facilely fabricated, providing an excellent long-term anti-corrosion performance for Mg alloys within the harsh environments. Mesoporous silica (MS) loaded with corrosion inhibitor benzotriazole (BTA) is grafted onto the surface of graphene oxide (GO), to synthesize GO-based nanomaterials, which can be uniformly dispersed in the epoxy (EP) coating through ring opening reaction and form the covalent bonds. Electrochemical Impedance Spectroscopy (EIS) results show that the modulus of the EP-GO-MS-BTA hybrid coating remains at 2.57 × 1011 Ω cm2 after immersion in 3.5 wt% NaCl solution for 15 days. In contrast to previously reported works that achieved the self-healing ability in acidity, the current EP-GO-MS-BTA coating represents an ultra-high self-healing efficiency of 1.2 × 108 Ω cm2 h−1 under acid 3.5 wt% NaCl condition (pH = 3). Due to the labyrinth effect, the impermeability of epoxy coating is enhanced by the ameliorative dispersity of GO sheet. In addition, the as-prepared GO-based nanomaterial can be used to load corrosion inhibitor BTA and possess H+ ion-responsive release property, leading to an improved corrosion protection. Combining the dual effects of superior GO dispersion and smart self-healing, it will provide a green and convenient synthetic method for constructing self-healing coatings with the excellent anticorrosion resistance.

Developing core-shell silica nanoparticles to create multifunctional coating with excellent antireflection, enhanced antifogging and anticorrosion performances

How to fabricate a multifunctional coating with controllable ultralow refractive index (RI), high antifogging and anticorrosion performances by a facile method is still one of the great challenges. In this work, a simple and time-saving approach involving a microwave-assisted sol-sel process was developed to fabricate a novel core-shell structured silica nanoparticle sol by co-condensation of perfluorodecyltriethoxysilane (F-DTOS) and tetraethoxysilane (TEOS) and self-condensation of F-DTOS. Results suggest that both the co-condensations and self-condensations not only give a layer of low surface energy –C10H4F17 groups on the silica particles but also enlarge the hybrid silica particle size, providing more and larger voids to form the high porosity. After spinning the silica nanoparticles on the substrate, the obtained optical coating exhibits the controllable ultralow refractive index (RI) and outstanding transparency. The minimum RI and maximum transmittance of our developed coating is up to ~1.04 and ~100 %, respectively. Moreover, because of the high porosity and the presence of low surface energy –C10H4F17 groups in the coating, the coating has the high hydrophobicity (water contact angle ~108.8°), which not only makes it excellent antifogging performance but also affords it high-efficient anticorrosion property. After immersion in a 3.5 wt% NaCl solution for 7 days, the Rct value of the coating could be higher than 7.3 × 104 Ω cm2. It is believed that our developed method used to fabricate such multifunctional coating does not need any costly equipments, complex steps and time-consuming, making it well suited for industrial application.

The potency of spores and biosurfactant of Bacillus clausii as a new biobased sol-gel coatings for corrosion protection of carbon steel ST 37 in water cooling systems

The structures of water cooling systems are prone to microbially-influenced corrosion (MIC) due to the favorable conditions for microbial growth. Biofilm formation accelerates corrosion, leading to reduced system efficiency, structural damage, and significant financial losses. Encapsulating viable bacterial spores and biosurfactant within a silica-based sol-gel coating offers an eco-friendly approach to prevent this type of corrosion. Bacillus clausii, known for its antimicrobial biosurfactant production capability, was utilized in this study to investigate the impact of spores and biosurfactant addition to silica-based sol-gel coatings in inhibiting biofilm formation and preventing corrosion in water cooling systems. Microbiological analysis of the biofilm was conducted using the total plate count method, while the corrosion process was analyzed through electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The viability of B. clausii spores within the sol-gel matrix was determined to be 20.8 %. The presence of bacterial spores and biosurfactant significantly increased the hydrophobicity of the sol-gel coating. Incorporating spores within the sol-gel matrix delayed biofilm formation for up to 12 days, while biosurfactant addition showed the smallest biofilm abundance (2.23×105 CFU/mL) at its maturation phase compare to others. After 180 days of incubation, analysis of Bode and Tafel plots demonstrated that the sol-gel coating containing biosurfactant maintained excellent anti-corrosion performance, exhibiting an impedance of 104 Ω cm2, Ecorr of -0.398 V vs SCE, and icorr of 0.51 µA/cm2. SEM-EDS analysis of the surface sample revealed a comparably smooth and uniform surface with a minimal abundance of exposed Fe atoms at 0.12 %. In conclusion, this study demonstrated the high potency of the sol-gel coating supplemented with biosurfactant in inhibiting biofilm formation and corrosion on metals in water cooling systems.

The new insights towards smart pH-responsive anticorrosion coating based on HNTs carrying synergistic inhibitors: Experimental and molecular simulation

Corrosion of steel structures in reinforced concrete structures in coastal areas has long been an urgent concern. In this study, a combined corrosion inhibitor, consisting of benzotriazole (BTA) and sodium D-gluconate (SD), was loaded onto halloysite nanotubes (HNTs) using the vacuum negative pressure method. Then, the HNTs were encapsulated with biomass polyelectrolytes sodium alginate (SA) and chitosan (CS) by layer-by-layer self-assembly technique to prepare BTA/SD-HNTs@CS/SA (FHNTs) composite. Furtherly, a functional epoxy coating (FEP) with pH-responsive and long-term service ability was successfully fabricated. It is found that BTA/SD was released in large quantities under alkaline (pH = 11) and acidic (pH = 2) conditions, while essentially no release under neutral condition. The electrochemical impedance spectroscopy (EIS) measurements demonstrate that the corrosion protection ability of FEP was significantly stronger than pure epoxy coating (EP), and the addition of 2 % FHNTs having the most excellent anticorrosion performance with the maximum charge transfer resistance (Rct) value (4.8 × 106 Ω cm2) after 4 weeks of immersion, which was 2 orders of magnitude greater than the pure EP coating. Particularly, molecular dynamics (MD) simulations indicate that FEP coating has better barrier properties than EP, while the fractional free volume (FFV) value of H2O and Cl− in EP was 9.1 % and 5.1 %, respectively, whereas this value decreased by about 15 % to 7.7 % and 4.4 % in FEP. The results of density functional theory (DFT) calculations suggest that the released BTA and SD molecules have a synergistic adsorption effect on the surface, which can form a compact film to hinder the invasion of corrosive species. Overall, this study provides new insights for developing smart pH-responsive and superior anticorrosion coatings.

Synergistic effect of water solubility sulfhydryl compound and rare-earth ions on the microstructure, composition, and corrosion resistance of brass

The aim of the present research is to develop one new strategy to modify the brass surface with well anticorrosion performance. Here, utilizing the synergistic effect between thioglycolic acid (TGA) and Y(III), one organic–inorganic hybrid film composed of a self-assembled film at the top and an oxide film at the bottom was fabricated on brass surface. The formation process of the hybrid film contained the parallel adsorption of TGA molecules, surface oxidation of copper accompanied by zinc dissolution, interface deposition of Y2O3 and assembly of Cu-TGA chelates. Electrochemical results indicated that the protection efficiency was 99.2% under the optimum conditions and the value remained at 92.1% after 12 h immersion in 3.5 wt% NaCl solution. Due to the good water solubility of the film-forming substance and excellent anticorrosion performance of the fabricated film, this strategy has important application potential in the field of surface functionalization of copper alloys.

Inter- and intra-molecular synergism in designing MgO-MCC composite-based coating: An efficient inhibitor for excellent anticorrosion performance

Polymer-based corrosion inhibitors are characterized by high efficiency, low cost, and eco-friendliness; however, their underlying mechanisms and modes of action remain poorly understood, presenting a significant challenge in optimizing their performance and effectiveness in practical applications. In this study, we successfully synthesized and thoroughly characterized a novel nanocomposite, combining magnesium oxide (MgO) nanoparticles with microcrystalline cellulose (MCC), and assessed its potential as a corrosion inhibitor for XC18 steel in an HCl 1.0 mol/L environment. The anticorrosive performance of the MgO-MCC composite for XC18 steel under harsh acidic conditions were investigated via electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and surface characterization with a scanning electron microscope (SEM). Morphological analysis suggested the formation of a protective barrier with a fiber-like architecture on the XC18 surface that hindered corrosion. The electrochemical results revealed an increased inhibition performance of MgO-MCC with increasing concentrations reaching a higher efficiency of 87% at 700 ppm. Also, EIS results displayed maximum corrosion resistance achievement in the presence of MgO-MCC-based material (about 147.50 Ω cm2) along with mixed protection mechanism. Advanced theoretical calculations based on density functional theory (DFT) and first-principles density-functional tight-binding (DFTB) were performed to understand the MgO-MCC behavior at metal interface as well as to explore the inter- and intra- molecular interactions involved in the hybrid material formation, complementing the experimental findings. The interfacial mechanism and structure engineering of MgO-MCC composite for functionalizing the surface of metal alloy were also investigated and discussed. MgO-MCC benefits from essential inter and intra-molecular interactions, leading to a robust adsorption layer. The parallel adsorption configuration and mutual interaction establish a stable hierarchical self-assembly structure and stabilize the Fe―O bonds, thus improving the chemical and physical bonding with XC18 steel surface. The results suggest that the synergistic combination of MgO nanoparticles and polar-rich MCC is a valuable approach for designing novel hybrid materials.

Preparation of PVDF-PDMS-SiO2 multi-stage rough superhydrophobic coating with excellent anti-corrosion and drag reduction performance via one-step cold spraying

Suitable superhydrophobic surface micromorphology, which can capture air underwater to form an air film, was used to decrease the solid-liquid contact area between the substrate and water, and thus reduce the intrusion of corrosive media and the resistance of movement. In this research, PVDF-PDMS-PF@μ/nSiO2 (PPPSS) multi-stage rough superhydrophobic coating was prepared on aluminum alloy by one-step cold spraying. Perfluorodecyltrimethoxysilane (PFDT) modified dual-scale SiO2 microparticles were used to provide the desired roughness. Low surface energy polymers polyvinylidene fluoride (PVDF) and polydimethylsiloxane (PDMS) were introduced as the polymer skeleton. The water contact angle of the PPPSS coating was 162.6°, with good superhydrophobicity. The coating exhibited excellent anti-corrosion that |Z|0.01 Hz was still three orders of magnitude higher than the bare substrate after 10 days of immersion. The flow experiment results showed that a maximum of 35 % drag reduction was achieved in Reynolds from 6 × 103 to 4 × 104. The equivalent circuit and drag reduction mechanism of the coatings were further investigated by combining surface morphology and material composition. Besides, the PPPSS coating demonstrated good stability and self-cleaning performance. The large-area superhydrophobic surface made by simple and convenient one-step cold spraying, is expected to have practical applications in marine transportation, underwater mapping, and pipeline transportation.

Significant promotion of the anti-corrosive performance of epoxy zinc-containing coating via in situ reduction of graphene oxide and simultaneous graft it with polyamide curing agent

Two different reduced graphene oxide, i.e. the chemical reduced GO grafted with the polyamide (PGO) and common thermal reduced graphene oxide (RGO), had been used to modify epoxy/Zn composite coatings and their anticorrosive behavior was studied and compared. PGO was innovatively incorporated into the epoxy composite coating during preparing the paint via the solve-thermal treatment of GO in polyamide-651 at 90 °C. Various analyses revealed that GO was reduced in situ and simultaneously grafted with polyamide macromolecules during the solve-thermal treatment. Compared to pristine GO and RGO, PGO displayed improved dispersibility in the resin diluent and its superior effect on improving the anti-corrosive performance of epoxy/Zn coating was confirmed by different corrosion test and surface analysis technique. Moreover, its optimum content in the composite paint was only 0.3 wt%. The excellent anti-corrosion performance of the composite coating could be attributed to the great barrier properties of PGO in the epoxy coating, as well as its good dispersion and compatibility to epoxy matrix.

Application of Organic Coating in Marine Anticorrosion

The development of navigation technology has increased maritime trade and the corrosion problem of ships has received more and more attention. Marine corrosions are mainly electrochemical, mechanical and biological corrosion. Normally, the countermeasures for marine corrosion include sacrificial anode protection, applied current cathodic protection and anti-corrosion coating. However, the first two still have great shortcomings. The sacrificial anode protection is limited by the potential difference between the metal electrodes, and the protection range is small. The applied current cathodic protection requires continuous external batteries, and the cost of detection and maintenance is high. The anticorrosive coating not only has excellent anticorrosive performance, but also has the advantages of simple operation process and low cost. Hence, anticorrosive coatings have been gradually applied to ship anticorrosion. Finally, this paper reviews the application of organic coating method in ship mooring corrosion protection, and introduces three kinds of epoxy anticorrosive coatings, polyurethane anticorrosive coatings and graphene anticorrosive coatings to meet the increasingly stringent development requirements of marine anticorrosive coatings.

Fabrication of branch-like Aph@LDH-MgO material through organic-inorganic hybrid conjugation for excellent anti-corrosion performance

Layered double hydroxides (LDH) frameworks have shown significant enhancement in stability and reusability, and their tailorable architecture brings new insight into the development of the next generation of hybrid materials, which attracted considerable attention in many fields over the years. One of the factors contributing to the widespread applicability of layered double hydroxides is their adaptable composition, which can accommodate a wide spectrum of potential anionic guests. This exceptional property makes the LDH system simple to adjust for various applications. However, most LDH systems are synthesized in situ in an autoclave at high temperatures and pressures that severely restrict the industrial use of such coating systems. In this study, LDH was directly synthesized on a magnesium alloy that had undergone plasma electrolytic oxidation (PEO) treatment in the presence of ethylenediaminetetraacetic acid, thereby avoiding the use of hydrothermal autoclave conditions. This LDH system was compared with a hybrid architecture consisting of organic-inorganic self-assembly. An organic layer was fabricated on top of the LDH film using 4-Aminophenol (Aph) compound, resulting in a smart hierarchical structure that can provide a robust Aph@LDH film with excellent anti-corrosion performance. At the molecular level, the conjugation characteristics and adsorption mechanism of Aph molecule were studied using two levels of theory as follows. First, Localized orbit locator (LOL)-π isosurface, electrostatic potential (ESP) distribution, and average local ionization energy (ALIE) on the molecular surface were used to highlight localization region, reveal the favorable electrophilic and nucleophilic attacks, and clearly explore the type of interactions that occurred around interesting regions. Second, first-principles based on density functional theory (DFT) was applied to study the hybrid mechanism of Aph on LDH system and elucidate their mutual interactions. The experimental and computational analyses suggest that the high π-electron density and delocalization characteristics of the functional groups and benzene ring in the Aph molecule played a leading role in the synergistic effects arising from the combination of organic and inorganic coatings. This work provides a promising approach to design advanced hybrid materials with exceptional electrochemical performance.

Anticorrosive superhydrophobic high-entropy alloy coating on 3D iron foam for efficient oil/water separation

Oil-spill remediation requires low-cost, high-efficiency, and operationally flexible oil-water separators, particularly those with superior corrosion resistance to extend their service life. Superhydrophobic 3D metallic foams are increasingly attracting tremendous attention due to their excellent mechanical stability and promising applications for continuous in-situ separation. Hence, superhydrophobic iron foams were fabricated via cyanide-free electrodeposition of a ZnFeCoNiMn high-entropy alloy (HEA) coating followed by non‑fluorine surface modification with tetradecanoic acid. Fluffy microspheres with hierarchical micro/nanostructure on the superhydrophobic HEA coating contributed to the superhydrophobicity of 3D iron foam. These foams exhibited highly efficient separation of oil and water even under violent stirring (700 rpm). Moreover, they achieved excellent anti-corrosion performance, with a decline in corrosion rate from 14.95 to 0.27 mm·a−1 in a 3.5 wt% NaCl solution, making it perfect for the harsh sea environment.

Halloysite@Polyaniline Nanoparticles Loaded with the Praseodymium (III) Cation for Improving Active Corrosion Protection of Waterborne Epoxy Coating.

The corrosion resistance of the waterborne epoxy coating is poor during long-term service, which greatly limits its widespread application. In this paper, the halloysite nanotubes (HNTs) were modified by polyaniline (PANI) and then used as nanocontainers to encapsulate the green corrosion inhibitor praseodymium (III) cations (Pr3+), obtaining HNTs@PANI@Pr3+ nanoparticles. A scanning electron microscope, transmission electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis were applied to characterize the formation of PANI and the absorption of Pr3+ cations. The corrosion-inhibiting ability of the HNTs@PANI@Pr3+ nanoparticles for iron sheets and the anticorrosion properties of the nanocomposite coatings were evaluated by the electrochemical impedance spectroscopy technique. The results indicated that the coating containing HNTs@PANI@Pr3+ nanoparticles exhibited excellent anticorrosion performance. After immersion in 3.5 wt % NaCl solution for 50 days, its Zf=0.01Hz value was still as high as 9.4 × 108 Ω cm2. The icorr value was 3 orders of magnitude lower than that of the pure WEP coating. The excellent anticorrosion property of the HNTs@PANI@Pr3+ coating could be attributed to the synergy of three beneficial factors, including evenly distributed nanoparticles, PANI, and Pr3+ cations. This research will provide theoretical and technical support for the development of waterborne coatings with high corrosion resistance.