Search Results (513)

The presented research delivers a comprehensive evaluation of anticorrosive cathodic electrodeposition (CED) coatings through an integrated performance and process capability analysis—an approach that remains extremely limited in the literature, particularly in the context of statistically designed experiments (DoEs) applied to CED systems. This study therefore addresses a notable gap by focusing on the role of polymerization variables in determining coating quality through DoE to quantify the influence on coating thickness uniformity, adhesion integrity and impact resistance, while all other deposition parameters were rigorously controlled. Prior to coating application, all specimens were prepared and conditioned in accordance with ISO 1513:2010. Coating thickness was determined in compliance with ISO 2808:2019, adhesion was characterized by cross-cut methodology according to ISO 2409:2020 and dynamic mechanical resistance was evaluated using a falling-weight apparatus in accordance with ISO 6272-1:2011. The obtained datasets were subjected to statistical capability analysis within the PalstatCAQ environment, providing Cp, Cpk, Pp and Ppk indices in line with ISO 22514-7:2021 and IATF 16949:2016 requirements. Results evidenced non-linear dependencies of thickness formation on curing parameters, with potential capability indices (Cp > 1.8; Pp ≈ 1.4) indicating favorable process dispersion, while performance indices (Cpk < 0.5; Ppk < 0.4) revealed systematic mean shifts and deviations from normality confirmed by Shapiro–Wilk and Anderson–Darling tests. Adhesion testing demonstrated a direct correlation between curing conditions and interfacial bonding, reaching ISO Grade 0 classification. Complementary impact resistance assessments corroborated these findings, showing that insufficient curing induced extensive cracking and delamination. Furthermore, SEM–EDX analysis performed on Sample n.3 of X₂ variable confirmed the chemical integrity and multilayered structure of the CED coating. 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

Pipeline anticorrosion patch spray coating is a critical process in pipeline construction and maintenance. It directly affects the adhesion between the pipe exterior and the heat-shrink sleeve and indirectly determines the quality of the coating bond. This study employs ANSYS FLUENT numerical simulations, complemented by on-site automated spray-gun experiments, to systematically investigate the influence of two key parameters—spray distance and gun traverse speed—on coating thickness distribution and uniformity. For both flat and cylindrical specimens, response surface methodology (RSM) applies to construct mathematical deposition models and to optimize process parameters. Simulation results indicate that increasing spray distance leads to edge thinning, while excessive traverse speed causes non-uniform thickness. Optimization improves coating uniformity by 18% on flat specimens and up to 15% on cylindrical specimens. Field validation demonstrates that the optimized process reduces process deviation from the target thickness to within ±10%. At the same time, the maximum relative error between simulation and experiment remains within 13.5%, and the deviation from the standard thickness is 12.25%. These findings provide solid theoretical foundations and practical guidance for automated spray-coating optimization, thereby enhancing the anticorrosion performance of pipeline joints. 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 work, low-zinc epoxy powder coating primers with anticorrosive properties were developed. For this purpose, single-walled carbon nanotubes (SWCNTs) were introduced into powder coatings. The obtained coatings were evaluated by performing the following tests: adhesion to steel, roughness, gloss, color, water contact angle, salt spray, electrochemical impendance spectroscopy (EIS), and transmission scanning microscopy (TEM). The anticorrosion resistance of the powder coating primers obtained depends on the zinc and SWCNT content, as well as the degree of dispersion in the paint. The mechanism of anticorrosion activity was proposed. Full article

In response to the challenges of metal corrosion detection and anti-corrosion coating performance evaluation in the marine environment of Zhoushan, this study proposes an improved object detection model, YOLO v5-EfficientViT-NWD-CCA, to enhance the recognition accuracy and detection efficiency of corrosion images on marine structures. Based on YOLO v5, the model incorporates the EfficientViT backbone network, NWD (Normalized Wasserstein Distance) loss function, and CCA (Criss-Cross Attention) attention mechanism, outperforming comparative models across multiple key metrics. Experimental results show that the proposed model increases precision from 0.73 to 0.76 (approximately 4% improvement) and raises the True Positive rate from 0.66 to 0.70 (approximately 6% improvement) according to the confusion matrix, demonstrating more stable overall detection performance. Building on this, the study combines the model’s detection results to conduct a quantitative analysis of the corrosion area of eight types of anti-corrosion coatings in two typical marine environments—tidal zones and fully immersed zones—across different exposure periods (24, 60, and 96 months). The results indicate that the tidal zone presents a harsher corrosion environment, with corrosion severity significantly increasing over time. Fusion-bonded epoxy coatings, powder epoxy coatings, and fluorocarbon coatings exhibit good corrosion resistance, whereas chlorinated rubber coatings and conventional epoxy coatings perform poorly. This study not only achieves intelligent identification and precise quantification of corrosion areas but also provides a scientific basis for the selection and evaluation of anti-corrosion coatings in different marine environments. 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

Superhydrophobic surfaces, characterized by water contact angles greater than 150°, have attracted widespread interest due to their exceptional water repellency and multifunctional applications. However, traditional fabrication methods often rely on fluorinated compounds and petroleum-based polymers, raising environmental and health concerns. In response to growing environmental and health problems, recent research has increasingly focused on developing green superhydrophobic surfaces, employing eco-friendly materials, energy-efficient processes, and non-toxic modifiers. This review systematically summarizes recent progress in the development of green superhydrophobic materials, focusing on the use of natural substrates such as cellulose, chitosan, starch, lignin, and silk fibroin. Sustainable fabrication techniques, including spray coating, dip coating, sol–gel processing, electrospinning, laser texturing, and self-assembly, are critically discussed with regards to their environmental compatibility, scalability, and integration with biodegradable components. Furthermore, the functional performance of these coatings is explored in diverse application fields, including self-cleaning, oil–water separation, anti-corrosion, anti-icing, food packaging, and biomedical devices. Key challenges such as mechanical durability, substrate adhesion, and large-scale processing are addressed, alongside emerging strategies that combine green chemistry with surface engineering. This review provides a comprehensive perspective on the design and deployment of eco-friendly superhydrophobic surfaces, aiming to accelerate their practical implementation across sustainable technologies. Full article

Cold gas dynamic spraying (CGDS) enables the production of protective coatings without melting or oxidation. In this study, Al–Zn–TiO₂ composite powders were prepared by wet agglomeration with binders and by dry mechanical mixing, and deposited onto mild steel substrates. COMSOL simulations of gas dynamics and particle acceleration identified optimal parameters (0.6 MPa, 600 °C, 15 mm, 90°), which were then validated experimentally. Coatings formed under these conditions exhibited dense microstructures, minimal porosity (~0.5%), and continuous, defect-free interfaces with the substrate. SEM and XRD confirmed solid-state bonding without new phase formation. Corrosion tests in 3.5% NaCl revealed a tenfold reduction in corrosion current density compared to bare steel, resulting from synergistic sacrificial (Zn), barrier (Al), and reinforcing/passivating (TiO₂) effects. Tribological tests demonstrated reduced friction (CoF ≈ 0.4–0.5) and wear volume. Compared with reported Al- or Zn-based cold- and thermal-sprayed coatings, the optimized Al–Zn–TiO₂ system shows superior performance, highlighting its potential for industrial anti-corrosion and wear-resistant applications. Full article

This study presents an in situ and laboratory evaluation of an innovative biocide-free nanocomposite coating designed to provide dual anti-corrosion and anti-fouling protection for EH36 naval steel in marine environments. The coating, comprising polyaniline nanorods, titanium dioxide nanoparticles, and Fe₃O₄-functionalized multiwalled carbon nanotubes embedded in a robust resin matrix, was systematically assessed through electrochemical, microscopic, and field-based methods. Laboratory immersion tests and extended exposures at two Mediterranean sea sites (Thessaloniki and Heraklion) revealed substantial improvements in corrosion resistance and significant suppression of marine biofouling over periods of up to 24 months. Electrochemical measurements demonstrated that coated specimens maintained a corrosion inhibition efficiency exceeding 93% throughout the study, exhibiting markedly lower corrosion current densities and higher charge transfer resistances than uncoated controls. Impedance spectroscopy and equivalent circuit modeling confirmed sustained barrier properties, while digital imaging and qualitative biological assessments showed reduced colonization by both micro- and macrofouling organisms. Comparative analysis with conventional biocidal and alternative eco-friendly coatings underscored the superior durability, environmental compatibility, and anti-fouling efficacy of the developed system. The results highlight the coating’s promise as a sustainable, high-performance solution for long-term protection of naval steels against the combined challenges of corrosion and biofouling in harsh marine settings. Full article

In order to enhance the anti-corrosion property of epoxy coatings on 7N01 aluminum alloy, cerium nitrate and zeolite particles were incorporated into a bis-(triethoxysilylpropyl)tetrasulfide (BTESPT) silane solution to pretreat the substrate. Scanning electron microscopy (SEM) and an electronic probe microanalyzer (EPMA) were used to characterize the morphology and chemical composition of the composite silane film. The corrosion performances of the epoxy coatings were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) and based on the morphology and chemical composition of the interfacial region after salt spray tests. The thickness of the composite silane film at 5% BTESPT doped with 5 × 10⁻³ M cerium nitrate and 0.5 g/L zeolite particles was about 2.1 μm. The composite silane film can provide active protection to the substrate surface beneath the epoxy coating. It promotes the impedance value of the coating at 10⁻² Hz by two to three orders of magnitude and greatly lessens the interfacial region corrosion between the coating and the substrate. This effect can be ascribed to the strong barrier effect of the composite silane film and cerium ions released from the silane network and the zeolite particles. Full article

An activation reaction sintering process was utilized to produce Cr-Cu-Mo-Ni porous alloys. Subsequently, weight loss measurements and electrochemical methods were applied to investigate the effect of Cr content ranging from 10wt% to 30wt% on the corrosive properties of Cr-Cu-Mo-Ni alloys in a 0.5 mol/L HF solution. Scanning electron microscopy (SEM) and X-ray diffraction analyses (XRD) were performed to assess the structural morphology and phase composition. As the results illustrated, Cr-Cu-Mo-Ni porous alloys possess good corrosion resistance, which is significantly higher than that of dense Ni and Cu alloys. The anti-corrosion performance of porous alloys is not proportional to the Cr content when the Cr concentration is gradually increased. When the chromium content is 20%, it exhibits the best corrosion resistance. Electrochemical measurements yielded similar results to weight loss measurements. With an increasing Cr content, double capacitive loops in electrochemical impedance spectroscopy (EIS) tests for Cr-Cu-Mo-Ni porous alloys first increased and then decreased, indicating that the corrosion process can be regulated by an electrochemical reaction. Meanwhile, after analysis, the results show that the corrosion products on the material surface adhere to the inner surface of the pores, thus improving the corrosion resistance. Full article

The response of titanium (Ti) thin films is closely related to their microstructure, which is extremely sensitive to the selected deposition parameters and geometrical configurations. The present study investigates the impact of geometrical factors on the growth of Ti thin films, focusing on how variations in growth geometry influence film microstructure, surface morphology, and corrosion resistance. Three Ti thin films were prepared using Glancing Angle Deposition (GLAD) in a custom-built DC reactive magnetron sputtering system. For the first sample, the target was positioned perpendicular to the substrate surface (α = 0°); for the second and third samples, the substrate holder was positioned at an angle of 85° regarding the target direction (α = 85°), incorporating a 180° azimuthal rotation for the last (to obtain a zigzag-like deposition). The thickness and morphological features of the thin films were investigated by SEM, while the surface morphology, specifically roughness, and crystallinity of the thin films were assessed by AFM and XRD, respectively. Continuous and alternating current techniques were used for electrochemical characterization of behavior in simulated body fluid. The obtained results show a clear tendency to an improvement in anticorrosion performances varying the nanoarchitecture of the films in comparison to the conventional-grown sample, with the inclined sample presenting a slight enhancement in corrosion resistance and the zigzag-grown sample having the best corrosion resistance properties of the three. Full article

The coupled factors of high temperature, high humidity, and high salinity in tropical marine atmospheres severely threaten the long-term service performance of power transmission and transformation infrastructure. This paper establishes an accelerated cyclic testing protocol (salt spray → drying → damp heat → drying) to evaluate performance and elucidate the dynamic corrosion failure mechanisms of the organic Zn14Al1.4 composite coating. By integrating multiphysical characterization techniques (SEM, EDS, XPS) with electrochemical analysis, this study for the first time elucidates the dynamic transformation of corrosion products: initially dominated by Zn(OH)₂, progressing to complex passive phases such as Zn₅(OH)₈Cl₂·H₂O, Zn₅(OH)₆(CO₃)₂, and Zn₆Al₂(OH)₁₆CO₃ in the mid-term, and ultimately dominated by Fe-based products (FeO, Fe₂O₃, Fe₃O₄, FeOOH) that drive interfacial failure. And a four-stage corrosion evolution model was defined: incubation period, accelerated degradation phase, substrate nucleation stage, and catastrophic failure phase. The investigation reveals a shift in the coating/substrate interface failure mechanism from purely physical barrier effects to electrochemical synergy, providing a theoretical framework for the optimized design and service-life prediction of anticorrosive coatings for transmission and transformation equipment in tropical environments. Full article

We present a straightforward emulsion-induced interfacial anisotropic assembly method for in- situ synthesis of bowl-shaped, self-encapsulated mesoporous polydopamine (BMPDA) nanocontainers (M-M@P) loaded with 2-mercaptobenzimidazole (2-MBI). Results showed that the loading capacity of the bowl-shaped mesoporous polydopamine reaches 24 wt.%. The M-M@P exhibits a cumulative MBI release of 91.61% after immersion in a 3.5 wt.% NaCl solution at pH = 2 for 24 h, accompanied by a corrosion inhibition efficiency of 95.54%. Additionally, the acid-responsive M-M@P not only enables controlled release of MBI but also synergistically promotes the formation of a protective film on the carbon steel substrate via the chelation of PDA-Fe³⁺, thereby enhancing the self-healing performance of waterborne epoxy coatings. Full article