Anticorrosion Performance Research Articles

Effect of Sn on the micro-structure, composition and anti-corrosion performance of reduced glutathione film on copper

An organic-inorganic hybrid film was successfully constructed via reduced glutathione (GSH) and SnSO4 on copper surface. The adsorption of sulfhydryl groups (-SH) on copper was the prerequisite for the synergistic effect of GSH and SnSO4. The addition of Sn (II) into the film formation system could improve the corrosion protection efficiency of GSH film from 90.52% to 99.89%. SEM results demonstrated that the synergistic effect between GSH and Sn (II) can improve the connection of the film and substrate. The XPS results indicated that Sn elements participated in the formation of the film with Sn (II), Sn (IV) and Sn (0). The excellent corrosion resistance of the film was attributed to the close connection between the film and the substrate and the doping of Sn with three valence states.

Surface wettability control and electron transport regulation in zerovalent iron for enhanced removal of emerging polystyrene microplastics-heavy metal contaminants

Emerging microplastics-heavy metal (MPs-HM) contaminants in wastewaters pose an emerging health and environmental risk due to their persistence and increasing ecological risks (e.g., “Trojan horse” effect). Hence, removing MPs in solution and preventing secondary releases of HM has become a key challenge when tackling with MPs pollution. Leveraging the hydrophobic nature of MPs and the electron transfer efficiency from Fe0 to HM, we demonstrate an alkylated and sulfidated nanoscale zerovalent iron (AS-nZVI) featuring a delicate “core-shell-hydrophobic film” nanostructure. Exemplified by polystyrene (PS) MPs-Pb(II) removal, the three nanocomponents offer synergistic functions for the rapid separation of MPs, as well as the reduction and stabilization of Pb(II). The outmost hydrophobic film of AS-nZVI greatly improves the anticorrosion performance of nanoscale zerovalent iron and the enrichment abilities of hydrophobic MPs, achieving a maximum removal capacity of MPs to 2725.87 mgMPs·gFe−1. This MPs enrichment promotes the subsequent reductive removal of Pb(II) through the electron transfer from the iron core of AS-nZVI to Pb(II), a process further strengthened by the introduced sulfur. When considering the inevitable aging of MPs in wastewaters due to mechanical wear or microbial degradation, our study concurrently examines the efficiencies and behaviors of AS-nZVI in removing virgin-MPs-Pb(II) and aged-MPs-Pb(II). The batch results reveal that AS-nZVI has an exceptional ability to remove above 99.6 % Pb(II) for all reaction systems. Overall, this work marks a pioneering effort in highlighting the importance of MPs-toxin combinations in dealing with MPs contamination and in demonstrating the utility of nZVI techniques for MPs-contaminated water purification.

Corrosion Protection of Q235 Steel Using Epoxy Coatings Based on Polyaniline Loaded with Benzotriazole

Polyaniline (PANI) doped with hydrochloric acid and phytic acid are prepared as benzotriazole (BTA) inhibitor carriers, and their anticorrosion properties are studied on epoxy resin-coated Q235 steel. The structure and morphology of the prepared PANI materials are investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The thermal stability of PANI and its release rate of corrosion inhibitor are measured, and the test results indicate that hydrochloric acid-doped PANI can accommodate a larger amount of corrosion inhibitor. The results of contact angle and water absorption tests show that the PANI loaded with BTA can improve the hydrophobicity and reduce the water absorption of the coating. The anticorrosion performances of epoxy coatings with 0.6 wt% PANI are investigated in 3.5 wt% NaCl solution using electrochemical tests. The experimental results reveal that PANI loaded with BTA shows a good anticorrosion effect in the epoxy coating. Particularly, phytic acid-doped PANI loaded with BTA has a better inhibition efficiency (93.6%), which is superior to hydrochloric acid-doped PANI loaded with BTA (86.4%).

Effects of spraying power on Fe-based amorphous coatings

To avoid the corrosion damage caused by cavitation and sediment erosion on the turbine blades, Fe-based amorphous coatings were deposited on steel of hydraulic turbine blades using plasma spraying with various spraying power. The effects of spraying power on the microstructure, electrochemical corrosion and wear resistance were systematically studied. Results show that the coatings have remarkable corrosion resistance and wear resistance compared with the substrate. Porosity is the most critical factor influencing the corrosion resistance of coatings. The anti-corrosion performance increases and the wear rate decreases as the spraying power increases. The coatings prepared at 25 kW has excellent corrosion resistance and wear resistance, with a corrosion rate of 0.011 mm·a−1, and a wear rate of only 5.91 mm3·N−1·m−1.

The metal anti-corrosion performance of light cured epoxy resin modified by zeolitic imidazolate frameworks (ZIF-8) with a core of polyaniline

In this paper, polyaniline (PANI) material was prepared by in-situ polymerization and mixed with zeolitic imidazolate frameworks (ZIF-8) to prepare PANI/ZIF-8 by surface modification. The light cured epoxy resin (RJ313) was modified by PANI/ZIF-8, and the PANI/ZIF-8/RJ313 anticorrosive coating was prepared. The chemical cross-linking of ZIF-8 with the epoxy resin can improve the cross-linking density and barrier property of the epoxy coating, thus improving the corrosion resistance of the coating. The encapsulation of PANI in ZIF-8 not only maintains the corrosion resistance of PANI, but also strengthens the dispersion of PANI under the action of ZIF-8 and improves the mechanical strength of the coating. A series of tests, such as the polarization test and electrochemical impedance test, proved that PANI/ZIF-8/RJ313 coating strongly affects 304SS acid corrosion resistance compared with RJ313, ZIF-8/RJ313 and PANI/RJ313. In 0.5 mol L−1 sulfuric acid solution, the corrosion current Icorr of this coating attached to 304SS was as low as 0.0308 μA·cm−2, and the impedance value can reach 37971.00 Ω·cm2. This provides a new idea for improving the dispersibility and corrosion resistance of other anti-corrosion materials.

Co-electrodeposition of superhydrophobic NiCo/CeO2 coating with hierarchical nano/micro structure for corrosion protection of plain carbon steel

This study aimed to develop an effective corrosion protection strategy for carbon steel by employing a superhydrophobic NiCo coating modified with CeO2 nanoparticles through the co-electrodeposition method. The superhydrophobicity was achieved by adjusting the composite coating's morphology and surface roughness. The synergistic impact of CeO2 and EDA crystal modifier on the coating's morphology, composition, topography, corrosion protection performance, and wetting properties was systematically investigated. The SEM results revealed the formation of a flower-like nano/micro morphology in the presence of EDA, and this morphology was preserved with the addition of 4 g/L CeO2 into the electrolyte. Surface wettability was significantly influenced by the hierarchical nano/micro structure of the deposited coating, with an enhanced superhydrophobicity observed in the presence of CeO2. The increase in surface roughness and compaction, achieved by incorporating CeO2 nanoparticles into the hierarchical structure of the NiCo coating, played a pivotal role in creating a superhydrophobic surface. Furthermore, polarization and EIS tests demonstrated that the superhydrophobic NiCo-EDA/CeO2 coating exhibited excellent anti-corrosion performance for the carbon steel substrate. In this case, Ecorr shifted towards positive values, icorr decreased, and both charge transfer resistance and coating resistance showed a considerable increase compared to other studied coatings. The alteration of metal wettability to a superhydrophobic state, combined with the barrier role of the coating and the presence of ceramic reinforcements (CeO2), offers comprehensive protection to the steel substrate. This approach holds great promise for effectively controlling the corrosion rate of widely used engineering metals.

Corrosion behavior and mechanism of FeCoNi high-entropy alloy compared with X100 pipeline steel in a simulated alkaline soil environment

In this work, the corrosion behavior of FeCoNi HEA and X100 pipeline steel in a simulated Golmud soil environment was systematically studied utilizing electrochemical tests, surface analysis techniques and immersion measurement. The results indicate that FeCoNi HEA possesses superior anti-corrosion property than X100 steel by comparing the charge transfer resistance (Rct), passive current density (ip) and corrosion morphology. The microstructure and surface film are the principal factors causing the difference in corrosion resistance of the two alloys. More intact, uniform and dense passive film enhances the anti-corrosion performance of the HEA, while the nonprotective, loose and defective corrosion product film covering the surface of X100 steel is not conducive to inhibiting the corrosion of the steel substrate. The appearance of inclusions within the HEA can generate the micro-galvanic corrosion effect with the matrix, which promotes the substrate as an anode to induce pitting. Furthermore, multiple phases of X100 steel exhibits higher electrochemical activity compared to the HEA with a single Face Center Cubic (FCC) phase, which accelerates the corrosion of the steel. Moreover, the matrix of the HEA primarily experiences selected dissolution of Ni element.

Efficient self-healing coatings embedded with polydopamine modified BTA@DMSNs for corrosion protection

Dendritic mesoporous silica nanoparticles (DMSNs) were successfully prepared with a specific surface area of 608.8 m2/g and an average pore size of 24.2 nm, providing a strong support for the successful loading of benzotriazole (BTA). BTA@DMSNs were prepared using the vacuum impregnation method. A pH-responsive polydopamine (PDA) outer layer was self-polymerized on the surface to obtain BTA@DMSNs/PDA microcapsules. The pH-responsive BTA@DMSNs/PDA microcapsules were prepared with the high BTA content of 20.1 wt%. Mean diameter of microcapsules was 210 ± 25 nm. The release profiles under different pH conditions confirmed the pH-responsive behavior of BTA/DMSNs@PDA microcapsules. The coatings with 1 wt% BTA@DMSNs/PDA microcapsules exhibited optimal anti-corrosion and self-healing performance. The |Z|0.01Hz of EP/1 wt%/BTA/DMSNs@PDA remained the highest among all coatings even after being immersed in 3.5 wt% NaCl solution for 50 d through the EIS measurement. It only had a slight change from 3.8 × 1010 Ω·cm2 to 6.8 × 109 Ω·cm2, which was 80 times that of the EP for 50 d, indicating that the coatings had excellent long-term anti-corrosion effect and good shielding performance. Furthermore, the |Z|0.01Hz of the artificially cross-scratched coatings that were immersed for 30 d remained at 6.9 × 104 Ω·cm2, which was one order of magnitude higher than EP (6.3 × 103 Ω·cm2), and the surface of coatings remained intact, showing that the scratched coatings had outstanding self-healing performance.

Evaluation of microstructure, corrosion resistance performance, and mechanical properties of 316L austenitic stainless steel FCAW welded joints: a comparative study

ABSTRACT This research aims to not only examine the effect of different mixtures of Ar and CO2 on microstructural features and corrosion behavior of double-pass FCAW of 316L SS but also compare these characteristics with gas tungsten arc welding (GTAW) and self-shielded FCAW. Different shielding gas mixtures, namely 100%Ar, 100%CO2, 82%Ar+18%CO2 were used to make the specimens. All specimens represent biphasic microstructures containing austenite (Ɣ) and delta-ferrite (δ-ferrite). Based on the potentiodynamic (PD) test results, the anti-corrosion protection performance of the welded region was enhanced when using GTAW compared to self-shielded FCAW. Additionally, the impedance value of the GTAW joint was higher than that of the FCAW-welded specimens. The ductility of welded joints was ranked as GTAW > CO2 +Ar shielded FCAW > self-shielded FCAW > CO2 shielded FCAW. The ranking of transverse tensile strength was as follows: CO2 shielded FCAW> self-shielded FCAW > CO2+ Ar shielded FCAW> GTAW.

Dense Amorphous Passivation Layer Formed on Aluminum Alloy Surfaces by Femtosecond Laser-Assisted Oxygen-Rich Doping.

Aluminum (Al) alloy surfaces are prone to serious corrosion in humid and salt-laden environments, which promotes the development of numerous protective approaches. Although the amorphous state is more conducive to improve corrosion resistance compared with the crystalline state, it still faces coating design problems like insufficient adhesive strength and flaking-off tendency. Here, we propose a strategy of femtosecond laser-assisted oxygen-rich doping to in situ create a dense high-quality passivation layer on Al alloy surfaces. With respect to the femtosecond laser processing in traditional air ambience, the material surface modifications within the oxygen-rich environment demonstrate some distinctiveness. For the ridge area of the laser ablation grooves, the oxidation surface is separated into two layers: the outer region presents a loose and porous appearance similar to the observations in the air ambience, while the inner region exhibits complete and homogeneous oxidation, especially associated with the continuous distribution of the amorphous substance, in sharp contrast to the nanoscale discrete amorphous formation in the air case. Simultaneously, the high degree of material oxidization with the amorphous phase is also developed on the wallside area of the groove valleys, which is much different from the incomplete oxidation in the air ambience. As a result, the measured corrosion current decreases by 49 times to a value of Icorr = 1.19 × 10-10 A/cm2 relative to the laser treatment in the air environment. Such a method offers the prospect for elevating the anticorrosion performance of metal surfaces.

Enhancing flame retardancy, anti‐impact, and corrosive resistance of TPU nanocomposites using surface decoration of α‐ZrP

AbstractThe development of polyurethane composites with significant flame retardancy and corrosion resistance for widening its practical application is a great importance. In this study, supramolecular wrapped α‐ZrP (MCP@ZrP) was prepared via self‐assembly of melamine, cobalt ions (Co2+) and phytic acid (PA) on the surfaces of α‐zirconium phosphate (α‐ZrP). It was found that both compatibility and dispersion of α‐ZrP sheets in thermoplastic polyurethane (TPU) matrices were improved with the incorporation of organic supramolecular components in TPU/MCP@ZrP nanocomposites. Moreover, their fire‐retardant characteristic was significantly enhanced, along with effective suppression of smoke and toxic gas emission. By adding 5 wt% MCP@ZrP, peak heat release rate, total heat release, total smoke production, and total CO production of such nanocomposites were reduced by 35.66%, 18.01%, 15.52%, and 41.42%, respectively. The generation of a continuous and dense char layer benefited from well‐dispersed MCP@ZrP nanohybrids, which resulted in tortuous effect to impede heat diffusion and prevent the evaporation of volatile gasses. By means of the barrier effect of ZrP, TPU/MCP@ZrP composite films also showed improved anticorrosion performance. Effective interfacial adhesion, achieved by combining MCP supermolecules and α‐ZrP sheets, offers a viable approach to improve protective properties of TPU nanocomposites.Highlights Supramolecular‐wrapped α‐ZrP was prepared via self‐assembly strategy. MCP@ZrP showed good dispersion and interface adhesion within TPU matrices. MCP@ZrP enhanced the flame retardancy and mechanical performance of TPU. MCP@ZrP preventing smoke and toxic gas evaporation.

Double-layer with electroactive and superhydrophobicity based on polymer nanotubes to improve robustness and anti-corrosion performances

The phenomena of corrosion in metals have resulted in significant damage to the day-to-day lives of humans, the routine maintenance of engineering metal materials, and catastrophic corrosion damage has also triggered huge economic losses. Herein, we propose a double-layer PDVB/FSiO2-PDVB@PPy/EP sprayable coating with excellent robust superhydrophobicity and electroactive based on mass-producible polydivinylbenzene nanotubes (PDVB NTs) to apply in anti-corrosion of Q235 steel plate. On one hand, the electroactive base layer of PDVB@PPy/EP can constitute a physical barrier against corrosive media; On the other hand, cross-linked PDVB NTs containing FSiO2 NPs (PDVB/FSiO2 NTs) can form a superhydrophobic surface structure to avoid substrate corrosion from corrosive liquid. The water contact angle (WCA) of the composite coating is 163.9° and the sliding angle (SA) is 3.6°, indicating that the coating possesses excellent superhydrophobic properties. Remarkably, Cross-cut scratch, tape peel, and Taber abrasion tests confirm that the composite coating exhibits excellent robust performance. The pitting pit depth after 30 days of salt spray test is 4 μm, and following 60 days of immersion in a solution containing 3.5 wt% NaCl, the protection efficiency (P.E.%) reaches 94.79 %. These results suggest that the double-layer electroactive superhydrophobic coating exhibits excellent corrosion resistance.

Constructing PANI@CF hybrids enhanced epoxy coatings with integrated functionalities of interfacial enhancement, erosion wear resistance and anti-corrosion

Factors such as sediment erosion and diffusion of corrosive ions in the splash zone result in a serious decrease in the protective performance of organic coatings. Carbon fiber (CF) reinforced polymer coatings have attracted much attention due to the impressive high mechanical strength and reliable chemical stability, but their protection period for steel structures is usually limited by the surface inertness and poor interfacial compatibility of the original CF. Herein, we created a composite coating with excellent erosion and wear resistance and corrosion resistance through simple self-polymerization of polyaniline on carbon fibers. The PANI layer not only helped to improve the interfacial compatibility between fibers/resin, but also exerted its corrosion inhibition effect. The interfacial shear strength (IFSS) value of the modified PANI4@CF monofilament and resin (60.63 MPa) was 46.73 % larger than that of the unmodified CF monofilament. In the simulated splash zone, PANI4@CF5/EP composite coating showed the best erosion resistance and corrosion resistance, and the mass loss and volume loss after erosion test were reduced by 53.39 % and 50.10 %, respectively, compared with pure epoxy coating. The local electrochemical impedance spectroscopy (LEIS) value of PANI4@CF5/EP coating with artificial defect was one order of magnitude higher than the epoxy coating after 48 h immersion. Finally, the environmental conditions of the splash zone were simulated to evaluate the anti-corrosion performance and erosion resistance of the CF reinforced composite coatings, and the protective mechanism was discussed in depth, which has great significance to the development of protective coatings for the splash zone under extreme marine environments.

Superhydrophobic surface of biomass carbon-based PANI composite coatings with the biomimetic structure of goose feather for anticorrosion/antibiofilm applications

Biomass carbon (BMC)-based polyaniline (PANI) composite coatings with superhydrophobic biomimetic surfaces were fabricated through nanocasting to transfer the surface of natural goose feather (GF) to the polymer surface for anticorrosion and antibiofilm applications. First, the as-synthesized PANI powder without/with 1 wt% BMC was dissolved/dispersed in N-methyl-2-pyrrolidone and then dropwise added onto the negative soft template of polydimethylsiloxane, successfully transferring the pattern of natural GF surface to a series of biomimetic PANI coating surfaces (denoted by Bio-PANI and Bio-PANI-1). Scanning electron microscopy (SEM) investigated the surface morphology of biomimetic coatings and revealed the presence of micron-sized rachis decorated with many nanoscaled barbules. Compared with that for non-Bio-PANI coating, the contact angle (CA) increased from 92.88° ± 0.81° to 144.94° ± 0.87° for Bio-PANI and 152.46° ± 1.95°for Bio-PANI-1. For anticorrosion application, the electrochemical corrosion potential (Ecorr)/impedance (Z’) of PANI coating increased significantly (from −633.62 mV/7.41 × 105 Ω to −319.87 mV/1.05 × 107 Ω) compared with that of Bio-PANI-1 coating, indicating that the Bio-PANI composite superhydrophobic coating exhibited the best anticorrosion performance. For antibiofilm application, three types of bacteria (i.e., Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) were used to study long-term antibiofilm formation. The findings revealed that the superhydrophobic Bio-PANI-1 coated surface inhibited bacterial growth and hindered biofilm development. Furthermore, the inherent hydrophobicity of this surface played a crucial role in warding off bacterial adhesion, ensuring impressive sustained antibiofilm efficacy.

Study on physicochemical and anti-corrosion performance of methylsiloxane-based hydrophobic powder modified mortar

The porous hydrophilic nature of cement-based material is susceptible to water and corrosive media, severely reducing the durability. In this paper, methyl siloxane-based hydrophobic powder was prepared, and its effect on the physicochemical and anti-corrosion properties of mortar with different water-cement ratios were investigated. The results show that the addition of hydrophobic powder significantly improved the hydrophobic properties of mortars. Especially for the mortars with w/c ratios of 0.2 and 0.4, it showed superhydrophobicity with a water contact angle up to 156.5 ° and 152.3 ° respectively. Lower w/c ratio mortar has a denser microstructure, which reduces the water absorption rate of the mortar, and the hydrophobic powder enhances the hydrophobic effect of low w/c ratio mortar more significantly. The methyl siloxane groups in the hydrophobic powders will bind to the C-S-H gel in the mortar through Si-O bonding, preventing the C-S-H gel connections from forming a continuous network structure. This increased the pore volume and reduced the compressive strength by 14.6%-22.7%, but the total hydration degree was increased, and significant corrosion protection of the steel rebar was demonstrated.

Preparation and anticorrosion performance of graphene composited waterborne coatings

Waterborne coatings are safe and environmentally friendly and widely used in automobile, construction and other fields. The low hardness of films formed by water-based anticorrosion coatings and their poor anticorrosion effect can be resulted from the addition of hydrophilic substances, which make it easy for water penetration. In this experiment, glycidyl methacrylate (GMA), butyl acrylate (BA), methyl methacrylate (MMA), and acrylic acid (AA) were used as the polymerization monomers to enhance the hardness, adhesion, and film-forming properties of the coatings by introducing the epoxy bond of GMA in the synthesis. The appropriate formula ratios for the waterborne coatings were determined by conditioning the content of wetting agent, thickener, levelling agent, defoamer, and modified acrylic-based resin. Based on this formula, suitable additive ratios of graphene were determined by condition experiments. When the addition ratio of graphene was 0.6wt% - 0.8wt%, the obtained coatings exhibited satisfactory hardness, film-forming properties, strong adhesion and anticorrosive properties. The results of salt spray tests and potentiodynamic polarization experiments verified that graphene in a certain proportion can effectively block the penetration of water, so that the coating presented excellent properties.

Effect of Al3+ on the surface microstructure and film formation mechanism of Zr-based conversion coatings with improved corrosion resistance performance on cold rolled steel

Most Zr conversion coatings are prepared on Al alloys, with Al3+ from the substrate contributing significantly to the film growth process. Thus, the effect of Al3+ on the electrochemical characteristics, surface microstructure and film-formation mechanism of Zr-based conversion coatings on old- rolled steel (CRS) substrates was investigated by growing the coatings with and without Al3+ as an additive. Electrochemical tests indicated that the anticorrosion performance of the Zr-Al coatings prepared in the presence of Al3+ was greatly superior to that of Zr conversion coatings obtained in the absence of Al3+. Field-emission scanning electron microscopy and X-ray photoelectron spectroscopy analysis indicated that adding of Al3+ in the conversion bath changed the surface microstructure of the Zr coating, greatly promoted the deposition of Zr and F on the CRS substrate and increased the film thickness and density. Both coatings were embedded into the etched CRS substrates. The presence of Al3+ additive induced the formation of different coating components. The Zr coating mainly consisted of ZrO2 and some FeFx, whereas the Zr-Al coatings comprised of ZrO2, ZrOxFy, Al2O3, AlFx and some FeFx. The present study results confirm the key role of Al3+ as an additive in the film formation and growth process of Zr coatings and its effect on enhancing the anticorrosion performance of CRS substrates in NaCl solutions.

H-BN base triple-functional filler enhances the anti-corrosion performance of epoxy coating

The dispersion of hexagonal boron nitride (h-BN) in resin to prepare anti-corrosion coating has only a single physical shielding function, and does not inhibit the electrochemical reaction process, which significantly reduces the durability of anti-corrosion coating. In this paper, polyaniline with anodic passivating function was synthesized on the surface of h-BN by in-situ polymerization, and Ce3+ cation with corrosion inhibition was loaded into polyaniline/h-BN. Thus, a triple functional anti-corrosion filler Ce3+&PANI/h-BN with physical shielding - anode passivation - cathode corrosion inhibition was prepared. The microstructure, crystal form, element distribution, thermal stability and corrosion inhibition ability of the composite filler were characterized. The anti-corrosion, anti-friction and adhesion properties of EP/Ce3+&PANI/h-BN composite coating was investigated. EIS and Tafel test results show that the corrosion inhibition efficiency of Ce3+&PANI/h-BN is 55.5% and 89.67%, respectively. The low-frequency impedance modulus of the composite coating after 40 days of exposure is 13 times that of the pure EP coating, up to 9.79 × 109 ·cm2. The results of salt spray test also show that the barrier ability and anti-corrosion effect of the composite coating are significantly improved compared with the pure EP coating. The wear mass loss of the composite coating is reduced by 43.69% compared with the pure EP coating. This research provides a way to prepare multi-functional, high shielding, wear resistance anti-corrosion fillers to achieve long-term protection of coatings.

Enhancing anticorrosive performance of epoxy-based coatings using magnetite/graphene hybrids modified with ionic liquids

Hybrid materials based on magnetite (Fe3O4) and graphene nanoplatelets (GNP) were prepared by the in situ co-precipitation synthesis of Fe3O4 in the presence of GNP aqueous dispersion. Alkyl-phosphonium–based ionic liquids bearing bromide (IL102) and diethyl phosphate (IL169) as the counter-anions were used for the first time to improve the dispersion of GNP. The successful preparation of the hybrids and the final incorporation of the ILs in the hybrids were confirmed by thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. The exfoliation of the GNP sheets and the incorporation of Fe3O4 particles on the GNP surface were confirmed by transmission electron microscopy. The effect of different hybrids on the corrosion resistance of the epoxy coatings was evaluated in saline medium using by electrochemical impedance spectroscopy (EIS). Hybrids prepared by the in situ synthesis of magnetite (Mag@GNP) promoted better corrosion resistance than pure magnetite or those hybrids introduced into the epoxy coatings by physical blends, due to better dispersion of the former fillers into the epoxy matrix. The best anti-corrosion response was achieved using 5 % of Mag@GNP 102 due to the better filler dispersion and higher amount of incorporated ionic liquid in the system, which can act as inhibition agent for the corrosion process.

Fabrication and anti-corrosion performances of robust superhydrophobic surface on NAB via solution-etching

A labyrinth microstructure interconnected by micron and submicron acicular structures was successfully prepared by immersing nickel-aluminum bronze in 9 wt% FeCl3·6H2O solution at room temperature for 40 min. After being modified with 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (FAS-17), the microstructure surface displays robustly low-adhesion superhydrophobicity, and the water contact angle is above 160 ° on it. In addition, the superhydrophobic surface exhibits excellent corrosion resistance and stability in 3.5wt % NaCl aqueous solution and corrosion solution with different pH values.