Search Results (422)

The development of hybrid organic coatings for corrosion protection remains a key research priority. This study focuses on synthesising Layered Double Hydroxide (ZnGa-LDHs) intercalated with environmentally friendly disodium sebacate (SB) corrosion inhibitor, forming ZnGa-SB. To overcome the challenge of limited dispersibility in organic coatings, ZnGa-SB was combined with Graphene Nanoribbons (GNR), produced through the oxidative unzipping of multi-walled carbon nanotubes (MWCNT). The resulting composite, ZnGa-SB/GNR, was synthesised using an in situ hydrothermal method and incorporated into polyurethane (PU) enamel. The synergy between high-barrier GNRs and active ZnGa-SB creates a “labyrinth effect” that effectively inhibits the diffusion of corrosive species. Microstructural analysis, including XRD, FT-IR, Raman, TGA, FE-SEM, and EDS, confirmed the nanofiller structure. The nanofillers were embedded into acrylic resin (AC) for short-term anticorrosive testing in a 0.1 M NaCl solution and then into PU for long-term evaluation in a 3.5 wt% NaCl solution, using electrochemical impedance spectroscopy (EIS). The PU/ZnGa-SB/GNR coating exhibited a high impedance modulus of 5.90 × 10⁷ Ω cm² at |Z|_0.01 Hz, even after 2688 hours of immersion, indicating enhanced corrosion resistance. This coating demonstrated superior performance in cross-cut and pencil hardness tests and sustained less damage in salt spray analysis compared to other coatings. The synergistic effect offers a promising approach for developing next-generation hybrid anti-corrosive coatings. Full article

The bioinspired superhydrophobic surfaces have demonstrated many fascinating performances in fields such as self-cleaning, anti-corrosion, anti-icing, energy-harvesting devices, and antibacterial coatings. However, developing a low-cost, feasible, and scalable production approach to fabricate robust superhydrophobic surfaces has remained one of the main challenges in the past decades. In this paper, we propose an uncommon method for the fabrication of a durable superhydrophobic coating on the surface of the glass slide (GS). By utilizing the screen printing method and high-temperature curing, the epoxy resin grid (ERG) coating was uniformly and densely loaded on the surface of GS (ERG@GS). Subsequently, the hydrophobic silica (H-SiO₂) was deposited on the surface of ERG@GS by the impregnation method, thereby obtaining a superhydrophobic surface (H-SiO₂@ERG@GS). It is demonstrated that the micro-grooves in ERG can provide a large specific surface area for the deposition of low surface energy materials, while the micro-columns can offer excellent protection for the superhydrophobic coating when it is subjected to mechanical wear. It is important to note that micro-columns, micro-grooves, and nano H-SiO₂ jointly form the micro–nano structure, providing a uniform and robust rough structure for the superhydrophobic surface. Therefore, the combination of a micro–nano rough structure, low surface energy material, and air cushion effect endow the material with excellent durability and superhydrophobic property. The results show that H-SiO₂@ERG@GS possesses excellent self-cleaning property, mechanical durability, and chemical stability, indicating that this preparation method of the robust superhydrophobic coating has significant practical application value. Full article

To evaluate the slip resistance of high-strength bolted friction-type connections subjected to different corrosion-protection treatments, calibration tests were performed on six representative faying-surface conditions: sand-blasted (uncoated), epoxy zinc-rich primer, waterborne inorganic zinc-rich coating, alcohol-soluble inorganic anti-corrosion anti-slip primer, a complete multi-layer protective coating system, and cold galvanizing. Fifteen test groups comprising 45 tensile specimens were examined to determine slip factors, which were then compared with values recommended in domestic and international design standards. The results show that sand-blasted surfaces (W type) exhibit stable slip factors of μ = 0.43–0.45; alcohol-soluble inorganic primer surfaces (S type) provide the highest slip resistance with μ = 0.49–0.51, representing an increase of approximately 13%–18% compared with sand-blasted surfaces; and cold-galvanized surfaces (D type) achieve favourable performance with μ ≈ 0.44. Waterborne inorganic zinc-rich surfaces (A type) yield μ ≈ 0.33, corresponding to a reduction of about 25%, and are suitable for non-slip-critical connections. In contrast, epoxy zinc-rich primers (C type) and complete multi-layer coating systems (X type) present lower slip factors of μ = 0.26–0.28 and μ ≈ 0.23, corresponding to reductions of approximately 35%–45% and about 50%, respectively, indicating that the X-type treatment is unsuitable for slip-critical applications. The influence of bolt diameter is limited, with slip-factor variations within 5%–8% under the same surface condition, and no statistically significant effect confirmed by two-way ANOVA. These findings provide a quantitative experimental basis for the design, classification, and future standardization of friction-type bolted connections with coated faying surfaces. Full article

This study evaluates the performance of a semi-synthetic emulsifiable fluid with anticorrosive properties, tested as a potential substitute for temporary corrosion protection during the production of thrust bearings. Samples were exposed to 48 h in a condensation chamber in accordance with ČSN 03 8131. The fluid provided partial protection; however, initial signs of pitting corrosion were observed. Although the emulsion reduced the extent of corrosion, it was not fully effective under the tested conditions, indicating the need for further formulation improvements or alternative protective measures. Full article

Smart self-healing polymer materials are breaking open new pathways in industry, minimizing waste, and enhancing the long-term reliability of applications. Moreover, when they possess anti-corrosive properties, they effectively protect surfaces from wear and corrosion, leading to improved and more robust products. In the present work, we develop a series of new self-healing polyurethane coatings activated by temperature, through the encapsulation of vegetable oils (VO), namely olive, soybean, and castor oil, in the core of polyurea microcapsules (VO-MCs). Using a green method, water-dispersible microcapsules were embedded in water-based polyurethane matrices. Both the self-healing ability and the anti-corrosive properties of the respective films were evaluated after mechanical damage. Encapsulation allowed for the direct release of VOs into the damaged area; subsequently, the temperature increase reduced the viscosity of the oils, facilitating their flow and diffusion into the damaged area and accelerating the healing process. Soybean oil and olive oil showed remarkable performance in terms of self-healing and high anti-corrosion ability for the polyurethane coatings, while castor oil showed a limited anti-corrosion effect but quite satisfactory effectiveness in terms of self-healing. Overall, the study highlights the potential of using encapsulated oils in environmentally friendly, active coatings with dual action: corrosion protection and self-repair of damage. Full article

This study investigated the electrochemical deposition of a novel composite polymer, 3-methylpyrrole–sodium dioctyl sulfosuccinate/3-methylthiophene (P3MPY–AOT/P3MTP), as protective coatings on OL 37 steel for anticorrosion applications. The anionic surfactant sodium dioctyl sulfosuccinate used in the deposition process enhances the protective efficiency of the coating. The coating films were characterized by CV (cyclic voltammetry), FT-IR (Fourier-transform infrared spectroscopy), and SEM (scanning electron microscopy). The anticorrosive properties of OL 37 steel coated with P3MPY-AOT/P3MTP were investigated in 1 M HCl using potentiostatic and potentiodynamic polarization, as well as electrochemical impedance spectroscopy (EIS). The coated samples exhibited a corrosion rate nearly ninefold lower than the bare substrate, with protection efficiencies exceeding 90%. Optimal performance was obtained for electrochemical deposition of P3MPY-AOT/P3MTP at potentials of 1.0, 1.2, and 1.4 V, current densities of 3 and 5 mA/cm², and a molar ratio of 5:3 for 20 min. The influence of electrochemical polymerization parameters—including applied potential, current density, scan rate, cycle number, and monomer ratio—on the anticorrosion efficiency of the coatings was systematically evaluated, allowing the identification of optimal synthesis conditions. Overall, the results confirm that P3MPY-AOT/P3MTP coatings provide highly effective corrosion protection for OL 37 steel in acidic environments. Full article

This study evaluated locust bean gum (LBG), a polysaccharide thickening agent, as an anti-corrosion active compound against sweet corrosion for N80 carbon steel used in the oil and gas sector. The assessment involved weight loss and electrochemical measurements at different temperatures (e.g., 25 °C and 80 °C) and immersion durations (up to 168 h) in a CO₂-saturated 2 wt.% KCl solution. The electrochemical results showed that LBG effectively inhibited sweet corrosion at both temperatures, and its efficacy increased with its concentration, reaching maximum inhibition efficiency of 84.11% at 25 °C and 55.81% at 80 °C, using 0.3 g L⁻¹ of LBG after 24 h of immersion. At 25 °C, and with 0.3 g L⁻¹ of LBG, the inhibition action of LBG did not change, even after 168 h of immersion (e.g., 83.97%). At 80 °C, LBG showed a good inhibition up to 72 h (e.g., 47.04%), after which LBG had no additional protective effect. This result is attributed to the formation of a FeCO₃ layer that covered the entire metal surface, blocking the adsorption of LBG. Potentiodynamic tests revealed that LBG’s inhibitory effect is of a mixed type. The Temkin adsorption isotherm model accurately described the data, indicating that LBG adsorption involves primarily physical interactions, with some chemical contributions. Activation energy and heat of adsorption calculations support the physical nature of LBG’s adhesion. FTIR analysis confirmed the interaction between LBG and N80 carbon steel, while SEM-EDS provided visual evidence of LBG’s influence on the metal surface. Full article

An effective approach to maintaining uninterrupted coolant flow in heat supply systems—and thereby reducing energy consumption—is to prevent the formation of corrosion-scale deposits on the inner surfaces of metal pipes. This is typically achieved by performing anti-corrosion treatment on the coolant. However, the efficiency of this method depends on several factors, including pipe conditions, water flow rate, and water composition. To inhibit corrosion and scale formation on the internal surfaces of pipelines, specific inhibitors are used to create protective films on the metal surface. For strong adhesion of these films, preliminary chemical cleaning of the metal surface with low-concentration acid solutions is essential. This cleaning is usually performed in circulation mode for several hours. The activated surface enhances inhibitor adhesion, leading to the formation of films with improved protective properties. The quality of the anticorrosive films was evaluated using a JSM-6490LV scanning electron microscope equipped with INCAEnergy energy-dispersive microanalysis systems, HKL-Basic structural analysis, ContrAA-300 atomic adsorption spectrometer, and potentiostat IPC-Pro MF. Full article

In this study, nitrogen-doped graphene (NG) films were synthesized on copper foil sur-faces by chemical vapor deposition (CVD), and their anti-corrosion properties were comprehensively investigated. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) results showed that the graphene layer was uniformly formed and nitrogen atoms were successfully incorporated. Raman spectroscopy revealed that the sample obtained on a 30 μm thick copper foil had a high structural quality (low ID/IG value). Electrochemical measurements showed that the NG coatings significantly reduced the corrosion current density and rate compared to pure copper. In short-term tests, the highest inhibition efficiency (91.5%) was observed for the sample synthesized on a 200 μm thick copper foil. In long-term (up to 2 months) seawater immersion tests, the inhibition efficiency decreased slightly over time, but the NG coatings showed much higher anti-corrosion properties than pure copper at all times. Overall results proved that nitrogen-doped graphene is a potential material in protecting metals from long-term corrosion, not only in seawater but also in harsh environments. Full article

This article investigates the anticorrosive properties of Zr-ZrN coatings, including Zr-(Zr,Hf)N, Zr-(Zr,Ti)N, Zr,Hf-(Zr,Hf,Nb)N, and Zr,Nb-(Zr,Nb)N, deposited on AISI 321 stainless steel substrates. The hardness and elasticity modulus of these coatings, as well as their scratch test strength, were measured. Corrosion current densities were calculated using the polarisation resistance method and by extrapolating the linear sections of the cathodic and anodic curves under electrode polarisation. The structure and composition of the sample surfaces were analysed by transmission electron microscopy. Notably, the nitride coatings reduced the corrosion current density in a 3% aqueous NaCl solution at 25 °C by more than 10 times, from 6.96 for the uncoated substrate to 0.17 μA/cm² for the Zr-(Zr,Ti)N-coated sample. The addition of Ti nitride to Zr-ZrN led to the most significant decrease in the corrosion current density. However, the introduction of Nb caused an increase in the corrosion rate and a decrease in the polarisation resistance, and Hf did not affect the corrosion-protective properties of the studied nitride coatings. Full article

This study systematically investigates the corrosion inhibition mechanism of imidazoline (IM) and gallic acid (GA) within boron nitride-reinforced epoxy-phenolic composite coatings (GIBE) for subsea crude oil pipelines. Microstructural characterization via field emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS) confirms the formation of a molecularly dispersed system in acetone, wherein IM promotes interfacial passivation through amino-metal coordination bonding with the substrate. Electrochemical impedance spectroscopy (EIS) demonstrates a strong positive correlation between IM content and corrosion resistance. GA facilitates self-healing capacity by forming Fe³⁺-chelated barriers at localized defects (as verified by X-Ray photoelectron spectroscopy (XPS) analysis of Fe³⁺–GA complexes); however, its inherent hydrophilicity introduces microchannels, as evidenced by a 28.6% reduction in the water contact angle, which ultimately compromises the barrier performance at elevated concentrations. The optimized formulation (5 wt.% IM with 2 wt.% GA) exhibits protective performance in simulated seawater at 60 °C: after 7 days of immersion, the low-frequency impedance modulus (|Z|_0.01Hz) reaches 6.28 × 10¹⁰ Ω·cm² with no visible corrosion at scribed regions; after 28 days, |Z|_0.01Hz remains above 10¹⁰ Ω·cm², surpassing the service durability threshold of conventional epoxy coatings under high-temperature saline conditions. This work proposes a novel engineering approach for designing anti-corrosion coatings tailored to marine extreme environments. Full article

With the development of prefabricated buildings, the challenge of integrating fireproofing and anti-corrosion in steel structures has become increasingly prominent. Based on epoxy resin, we developed a multifunctional coating with high-flame retardant efficiency and corrosion resistance, which can be employed in the key parts of modular integrated construction (MiC), thereby enhancing the safety of the prefabricated buildings. Experimental data showed that the fire resistance limitation reached 124 min, the salt spray resistance 2540 h, and the adhesion grade 1. The limiting oxygen index (LOI) of the cured coating was 45%, corresponding to the V-0 classification in the vertical burning test from Underwriters Laboratories Inc. (Northbrook, IL, USA) (UL 94). Compared with the latest studies, the integrated formulation exhibits simultaneous gains in fire and corrosion protection, offering a promising single-layer solution for MiC. Full article

The aim of present study is to deposit protective coatings with various surface chemical states on AZ91D Mg alloy. Hydrothermal bioactive ceramic coatings are performed with a surface modification by the chemical bonding of self-assembled monolayers (SAM). The electrochemical corrosion behaviors of various surface-coated AZ91D alloy within DMEM cell culture medium related to their surface chemical states are evaluated through microstructure observations, XPS surface chemical bonding analysis, static contact angles measurements, potentiodynamic polarization curves, and immersion tests. XRD and high resolution XPS of F 1s analysis results show that the hydrothermal FHA coating with a phase composition of Ca₁₀(PO₄)₆(OH)F can be effectively and uniformly deposited on the AZ91D alloy. FHA-coated AZ91D displays better anti-corrosion performances and lower degradation rates than those of uncoated AZ91D alloy in the DMEM solution. Through the high resolution XPS analysis of O 1s and P 2p spectra, it is demonstrated that 1-butylphosphonic acid (BP), 1 octylphosphonic acid (OP), and dodecylphosphonic acid (DP) molecules can be effectively bonded on the FHA surface by a covalent bond to form SAM. BP/OP/DP-SAM specimens display increased static contact angles to show a hydrophobic surface. It demonstrates that the SAM surface treatment can further enhance the corrosion resistance of FHA-coated AZ91D in the DMEM solution. After 2–16 days in vitro immersion tests in the DMEM, the surface SAM-bonded hydrophobic BP/OP/DP-SAM layers can effectively inhibit and reduce the penetration of DMEM into FHA coating. Long alkyl chains of the dodecylphosphonic acid (DP) SAM represents superior enhancing effects on the reduction of corrosion properties and weight loss. Full article

In this study, polysaccharide xanthan gum (XG), used in the oil and gas industry as a thickening agent, was evaluated as an active anti-corrosion component against sweet corrosion at high temperatures and pressures in a saline environment for N80 carbon steel in the oil and gas industry. The evaluation involved measuring weight loss and conducting electrochemical assessments at 5 bar CO₂ partial pressure, different temperatures (e.g., 30 °C and 90 °C), and immersion times (up to 72 h). The electrochemical results indicated that XG effectively mitigated CO₂ corrosion at both low and high temperatures, demonstrating inhibition efficiencies of 70.10% at 30 °C and 61.41% at 90 °C using 1.0 g L⁻¹ of XG, after 24 h. The good inhibition efficiency observed even at high temperatures is likely due to the denaturation process that XG undergoes at high temperatures, where a rigid double-stranded helical structure transitions into two single-stranded, more flexible, worm-like macromolecular conformations. This increases the number and mobility of XG macromolecules available for adsorption on the metal surface. EIS measurements have shown that XG was capable of protecting the metal surface even after prolonged exposure. Potentiodynamic measurements indicated that the inhibitive action of XG is of a mixed type. The Temkin adsorption isotherm model provided a good fit for the observed data, and the calculated parameters suggested that the adsorption of XG primarily occurred through physical adsorption processes, with a contribution from chemical processes. The associated activation energy and the heat of adsorption further supported the physical nature of XG’s adsorption. FTIR analysis was employed to elucidate the interaction between the XG and the N80 carbon steel surface, while SEM-EDS analysis provided visual confirmation of the XG’s impact on the metal surface. Full article

Polyaspartic ester polyurea (PEP) elastomers are highly promising for self-healable protective coatings in industrial applications, yet their broader adoption is limited by insufficient mechanical and corrosion resistance. Herein, we develop a multifunctional PEP nanocomposite by incorporating Jeffamine D2000-functionalized graphene nanoplatelets (F-GNPs), prepared through a one-step mechanochemical process. This strategy promotes strong interfacial bonding and uniform dispersion, yielding synergistic property enhancements. At an optimal loading of 0.3 wt%, the PEP/F-GNP nanocomposite exhibited a substantial performance enhancement, with its tensile and tear strengths augmented by 263.0% and 64.2%, respectively. Moreover, the resulting coating delivered an 84.0% boost in impact resistance on aluminum alloy, along with enhanced substrate adhesion. Electrochemical and salt spray tests further confirmed its exceptional anti-corrosion performance. While the reinforcement strategy presented a classic trade-off with self-healing, it is critical to note that the nanocomposite preserved a high healing efficiency of 83.3% after impact damage. Overall, this scalable interfacial engineering strategy simultaneously enhances the material’s mechanical robustness and protective performance, while striking a favorable balance with its intrinsic self-healing capability, paving the way for next-generation coatings. Full article