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Highlights Excellent impedance matching through component modulation engineering. Rich heterogeneous interfaces are constructed to realize excellent electromagnetic wave (EMW) absorption performance. Long-term corrosion protection and excellent EMW absorption properties.

Magnesium (Mg) and its alloys possess many outstanding properties, showing great potential to be extensively applied in different fields. Unfortunately, they are highly susceptible to corrosion, especially to corrosive chloride ions. This causes huge economic loss and has restricted their applications in industry. Among different strategies, protective coatings/surface modifications attract considerable attention because they can reduce or even restrain corrosion by preventing contact with the external environment. This review focuses on the recent advances in various protective coating/surface modification technologies pertinent to Mg alloys to offer a clear picture for researchers and engineers in the relevant research area. The topics covered include anodic oxidation, plasma electrolytic oxidation, chemical conversion coating, sol-gel coating, laser cladding, cold spray, electrophoretic deposited coating, layered double hydroxide coating and superhydrophobic coating. In addition, the industrial applications of electrochemical (anodic oxidation and plasma electrolytic oxidation) and chemical conversion coatings are briefly presented. The existing issues and future perspectives are discussed to accelerate the broad applications of Mg alloys.

This study presents the design and experimental evaluation of advanced corrosion protection coatings for application on prestressing strands which are the core constituents of prestressed concrete structures such as bridges. Variety of self-heal coatings embodying corrective and protective phenomena in response to the degrading effects of corrosion have been designed and tested in simulated aggressive weathering conditions. Standard 7-wire prestressing strands coated with self-heal epoxy, self-heal toughened epoxy and hybrid epoxy coating systems were subjected to salt fog spray up to a duration of 2500 h, and 3M CalCl2, 3M NaOH, saturated Ca(OH)2 solutions and distilled water up to 45 days duration. Furthermore, rust creepage of the coated prestressing strands was measured after extended exposure to aggressive corrosive environment. Bond strength of the self-heal epoxy coated prestressing strands was evaluated through pullout test using high-strength concrete.Significant improvement in corrosion resistance, hydrolytic stability, marked reduction in rust creepage, and improved bond strength, brought about by the innovative self-heal epoxy coatings were recorded in laboratory tests. Furthermore, electrochemical impedance spectroscopy (EIS) data proved excellent corrosion protection qualities of self-healing coatings. The ATR-FTIR spectra of various self-heal epoxy coating systems and optic microscopic images of the coatings further verified these findings.

This research aimed to establish prevention guidelines and mitigate the effects of chloride penetration in micro-cracked concrete by enhancing the quality of additive materials or fly ash and employing galvanic cathodic protection to guard against steel corrosion. The effects of micro-crack deterioration in reinforced concrete beams on the corrosion of reinforcing steel bars were investigated. Fly ash (FA) was replaced ordinary Portland cement (OPC) at rates of 0 %, 15 %, 30 %, and 45 % by weight of binder, with a water-to-binder (W/B) ratio of 0.45. Prevention measures included removing large particle sizes of the fly ash, and grinding to achieve high fineness, ensuring that particles retained on a sieve No.325 were less than 5 %. The test results showed that increasing the replacement of OPC with FA improved the chloride penetration resistance of the concrete, with lower detected chloride content compared to OPC concrete, and reduced the weight loss of the reinforcing steel bars. Additionally, the improvement of fly ash (IPF concrete) reduced the electric current to less than 20 mA, whereas the control concrete (PC) exhibited electric currents of about 80–100 mA. Another effective method for protecting against steel corrosion is the use of galvanic cathodic protection (GCP) in concrete, which can help reduce the electric current to 10 mA. Guidelines and preventive measures are suggested to ensure that structures can withstand environmental over time, maintaining their reliability and safety throughout their service life.

This review examines recent advancements in surface treatment technologies for aluminum alloys used in sports equipment. We discuss conventional methods like chemical conversion coatings and anodizing, as well as emerging techniques such as plasma electrolytic oxidation, physical vapor deposition, and laser surface modification. The replacement of toxic hexavalent chromium with eco-friendly alternatives is highlighted as a key development. We also explore the potential of smart, self-healing coatings to extend equipment lifespan. Our analysis reveals that while significant progress has been made in enhancing corrosion resistance and mechanical properties, challenges remain in scaling up advanced treatments for industrial implementation. The review concludes that continued innovation in surface treatments will be crucial for improving the performance, safety, and sustainability of aluminum alloys in sports applications, ultimately benefiting athletes and manufacturers alike.

Storing the main material for additive technologies, i. e. metal powder compositions made from steels and alloys with low corrosion resistance, is a challenge. We studied the protective ability of coatings applied by chemical heat treatment (CHT) to the surface of a steel powder, which has low resistance against atmospheric corrosion. Long-term two-year tests of powder samples with various coating compositions were carried out at natural atmospheric humidity and ambient temperature in the Northwestern Federal District of the Russian Federation. The chemical composition of the samples was evaluated before and after the test. The chemical composition and morphology of the particles were determined by electron microprobe (EMP) using a scanning electron microscope (SEM). It is shown that coatings applied by the CHT method do not create continuous protection and accelerate corrosion processes in comparison with the heat-treated powder of the initial steel.

Traditional rivets have been a longstanding choice for securing aircraft components as permanent fasteners. A new technique called friction stir spot welding (FSSW) is gaining popularity as a rivet replacement. Despite its advantages, dissimilar FSSW joints are susceptible to corrosion, which can lead to property degradation. This study explored the potential of superhydrophobic (SH) coating as a corrosion inhibitor for FSSW joint aerospace alloys, particularly aluminum alloy (AA). The study involved a comparison of the corrosion resistance between SH-coated dissimilar (AA2024-T3 and AA7075-T6) and similar (AA2024-T3 and AA2024-T3) FSSW joint specimens. Notably, SH-coated dissimilar FSSW joint specimens demonstrated an exceptional average water contact angle (WCA) of 156°, confirming their SH nature. The study further incorporated the design of experiments (DOE) and statistical analysis to optimize constituent parameters and enhance the performance of SH coating. Durability testing indicated that SH-coated dissimilar FSSW joint specimens exhibited high resistance to acetone without influencing the WCA of 148°. Only a slight decrease in the WCA was observed when specimens were submerged in an acidic solution, where the WCA reduced to 142° from the original WCA of 158°. Also, specimens were stable and maintained the WCA of 154° when heat-treated at the temperature of 230 ℃. Moreover, a cross-cut adhesion test revealed that less than 5 % of the coating material was lost in SH-coated dissimilar FSSW joint specimens. Additionally, the electrochemical study evaluated the anti-corrosion performance of SH-coated dissimilar FSSW joint specimens, where the specimens were immersed for 6 days in 3.5 wt% NaCl solution. After 6 days in 3.5 wt% NaCl solution, specimens remained very close to SH, maintaining the WCA above 140°. Also, the electrochemical results demonstrated that the anti-corrosion performance of the SH-coated dissimilar FSSW joint specimens was enhanced with a lower corrosion rate of 37.56 mpy and current density of 0.428 µA/cm² as compared to the uncoated specimens. The variations in corrosion rates and current densities of the SH-coated dissimilar and similar FSSW joint specimens were very minimal, which proves that the application of SH coating on the FSSW joint specimens is suitable to alleviate corrosion-related problems in FSSW joints.

The corrosion of metals is very important, both economically and environmentally, and is a serious concern. Since the past decades, traditional (chemical) corrosion inhibitors to prevent corrosion have been and are still being used. Although these inhibitors can be said to be a good choice among other protection techniques because of their good efficiency, the toxicity of many of them causes environmental problems, and, due to the change in the laws on the use of chemicals, many of them are no longer allowed. Hence, during the past years, research on green corrosion inhibitors (GCIs) increased and very favorable results were obtained, and now they are very popular. It can be said that biodegradability and easy preparation are their most important factors. Meanwhile, the use of plants, especially their extracts, has been studied a lot. Plant extracts contain compounds that have anti-corrosion properties. In this review, the use of plants as GCIs is investigated, focusing on recent advances in their use. Also, the phenomenon of corrosion, corrosion protection (including coatings, nanoparticles, and chemical inhibitors), and other GCIs are briefly reviewed.

Black oxide coatings on 6061 Al alloy were produced by plasma electrolytic oxidation (PEO) process in silicate- and phosphate-rich base electrolytes with addition of ammonium metavanadate (NH4VO3), respectively. The characteristics of PEO processes and resulting coatings were investigated. The thermal control properties of the coatings were measured. The corrosion protection performances of the coatings in an acidic environment were evaluated. Results show that the base electrolytes have significant influence on the PEO discharge behavior, coating characteristics and properties. There are more intensive discharges in silicate-rich electrolyte with addition of NH4VO3 (denoted as “Si–V″) than that in phosphate-rich electrolyte with addition of NH4VO3 (denoted as “P–V”), leading to higher thickness and more defects for the Si–V coating. Both Si–V and P–V coatings are characterized by black color in appearance due to the formation of V-containing compounds. However, the P–V coating has higher contents of V-containing compounds and therefore lower lightness and higher solar absorptance (αs) than the Si–V coating. In addition, the P–V coating exhibits better corrosion protection performance and color durability compared with the Si–V coating in acidic NaCl solution (pH = 3.1⁓3.3) due to the formation of AlPO4 in the coating. It is demonstrated that phosphate-rich base electrolyte with addition of NH4VO3 is a good candidate for getting stable black therm control coatings on Al alloy for practical applications in harsh environment.

Through the analysis of typical corrosion cases and the distribution of corrosion media, the corrosion patterns of petrochemical hydrogenation units were summarized. The main types of corrosion were identified as: crystallization of NH4Cl and under-deposit corrosion in the reaction effluent system, erosion corrosion by NH4HS, dew point corrosion by HCl and wet H2S corrosion in the circulating hydrogen desulfurization tower and stripping tower. The key influencing factors of various typical corrosion mechanisms in hydrogenation units were identified, and targeted corrosion protection measures were proposed, encompassing the selection of equipment and pipeline materials, optimization of operation and enhancement of corrosion monitoring and detection. This paper offered significant guidance for reducing the risk of equipment and pipeline corrosion and ensuring the long-term safe operation of hydrogenation units.

Steel structures are exposed to multiple environmental impacts that lead to reduced durability. Organic paint systems are a resilient mechanism to protect hydraulic steel structures from corrosion. Coatings lead to a decreased corrosion progress at damaged areas. In this work, we investigated the time dependency of undercoating corrosion in the neutral salt spray test in detail by conducting a long-term experiment. Thereby, the fundamental model of corrosion progress was investigated, leading to an increased reliability in approval procedures of coatings and in the choice of test parameters.Additionally, repair materials for on-site repair of damaged coatings were investigated in weathering tests to compare their performance with conventional coatings. These materials are used for short-term repairs of small damaged areas in order to postpone replacement of ailing structures, thus enhancing the durability of steel structures.

In this work, chitosan and chitosan/salicylate coatings were prepared by EPD on AZ91D Mg alloy to improve the corrosion resistance of the substrate in a simulated physiological solution. The effect of two concentrations of salicylate on the morphology and anticorrosive behaviour of the coatings was evaluated. The results showed that the addition of 0.50 g/L sodium salicylate to the chitosan formulation decreased the corrosion rate of the chitosan coating from 0.0025 ± 0.0003 to 0.0007 ± 0.0004 mA cm−2. From the results of electrochemical impedance spectroscopy (EIS) and Fourier Transform Infrared (FTIR) analysis, it can be concluded that the presence of salicylate in the coating leads to a self-healing effect that contributes to an improved corrosion protection. In addition, the presence of salicylate in the coating has been shown to increase antibacterial activity against both Gram-positive and Gram-negative bacteria. It has been demonstrated that salicylate can be released from the coating, which has an anti-inflammatory effect. In this way, a novel chitosan/salicylate coating was developed for the first time on a Mg alloy for bactericidal effect, release of salicylate and corrosion protection in simulated physiological solution. So far, chitosan and salicylate have not been investigated as a combination for the development of multifunctional coatings on Mg alloys. In addition, the self-healing effect of salicylate ions in a chitosan coating was established for the first time.

This study focuses on the evaluation of the influence of NaAlO2 content in the phosphate electrolyte on the properties of the plasma electrolytic oxidation coating formed on magnesium alloy EV31. The additions of NaAlO2 used were 4, 8, 12 and 16 g. The PEO coating was applied using a pulse regime with a frequency of 100 Hz, a duty cycle of 10 % and a current density of 0.05 A cm−2 for 10 min. The time to reach the initial dielectric breakdown was shortened by the addition of NaAlO2. The incorporation of NaAlO2 resulted in diminished porosity, reaching a minimum at an addition of 8 g/l NaAlO2. At the same time, the presence and extent of microcracks in the coating were enhanced. Based on elemental mapping and phase composition analysis by XRD, it can be concluded that the coatings without the addition of NaAlO2 are composed mainly of MgO and Mg3(PO4)2. After the addition of NaAlO2, the spinel phase MgAl2O4 was present in the coating, the ratio of which increased with increasing aluminate content. The highest polarisation resistance after 168 h was achieved by the samples with the addition of 4 g/l NaAlO2 after 10 min of PEO process time.

Magnesium (Mg) alloys are lightweight materials with excellent mechanical properties, making them attractive for various applications, including aerospace, automotive, and biomedical industries. However, the practical application of Mg alloys is limited due to their high susceptibility to corrosion. Plasma electrolytic oxidation (PEO), or micro-arc oxidation (MAO), is a coating method that boosts Mg alloys’ corrosion resistance. However, despite the benefits of PEO coatings, they can still exhibit certain limitations, such as failing to maintain long-term protection as a result of their inherent porosity. To address these challenges, researchers have suggested the use of inhibitors in combination with PEO coatings on Mg alloys. Inhibitors are chemical compounds that can be incorporated into the coating or applied as a post-treatment to further boost the corrosion resistance of the PEO-coated Mg alloys. Corrosion inhibitors, whether organic or inorganic, can act by forming a protective barrier, hindering the corrosion process, or modifying the surface properties to reduce susceptibility to corrosion. Containers can be made of various materials, including polyelectrolyte shells, layered double hydroxides, polymer shells, and mesoporous inorganic materials. Encapsulating corrosion inhibitors in containers fully compatible with the coating matrix and substrate is a promising approach for their incorporation. Laboratory studies of the combination of inhibitors with PEO coatings on Mg alloys have shown promising results, demonstrating significant corrosion mitigation, extending the service life of Mg alloy components in aggressive environments, and providing self-healing properties. In general, this review presents available information on the incorporation of inhibitors with PEO coatings, which can lead to improved performance of Mg alloy components in demanding environments.

This study aimed to prepare a facile hierarchical aluminium surface using a two-step process consisting of chemical etching in selected concentrations of CuCl2 solution and surface grafting through immersion in an ethanol solution containing 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane. The goal was to achieve superhydrophobic characteristics on the aluminium surface, including enhanced corrosion resistance, efficient self-cleaning ability, and improved anti-icing performance. The surface characterisation of the untreated aluminium and treated in CuCl2 solutions of different concentrations was performed using contact profilometry, optical tensiometry, and scanning electron microscopy coupled with energy dispersive spectroscopy to determine the surface topography, wettability, morphology, and surface composition. The corrosion properties were evaluated using potentiodynamic measurements in simulated acid rain solution and salt-spray test according to ASTM B117-22. In addition, self-cleaning and anti-icing tests were performed on superhydrophobic surfaces prepared under optimal conditions. The results showed that the nano-/micro-structured etched aluminium surface with an optimal 0.5 M concentration of CuCl2 grafted with a perfluoroalkyl silane film achieved superhydrophobic characteristics, with water droplets exhibiting efficient corrosion protection, self-cleaning ability, and improved anti-icing performance with decreased ice nucleation temperature and up to 545% increased freezing delay.

In this research, nickel oxide (NiO) nanoparticles with different concentrations of 1, 2, 3, and 4 wt% were added to a zinc-rich ethyl silicate (ZRES) coating containing 90 wt% zinc dust particles to promote the cathodic and barrier performance of coating systems. FTIR, XRD, and EDX analysis indicated the chemical composition and created bonds in ZRES coatings. SEM, AFM and TEM images showed the surface roughness and particle size in ZRES structure. Also, TEM confirmed the uniform dispersion of NiO nanoparticles in the coating matrix loaded with 3 wt% NiO particles. The effect of NiO content and the anticorrosion behavior of nanocomposite coatings were investigated by different techniques, including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP) and salt spray tests. Results revealed that ZRES coatings containing 3 wt% NiO nanoparticles had boosted sacrificial anode and barrier protection during 120 days of immersion in a 3.5 wt% NaCl solution. The addition of 3 wt% NiO into the coating system significantly reduced corrosion products and blisters while increasing corrosion resistances from 3069 Ω cm2 to 16482 Ω cm2 compared with the control ZRES sample. This high-performance anticorrosion behavior of the nanocomposite coatings is mostly due to the NiO nanoparticles, which have the capability to moderate the zinc dissolution rate in addition to improving the barrier by filling porosity and creating tortuous paths.

Smart micro-arc oxidation (MAO)/epoxy resin (EP) composite coatings were formed on AZ31 magnesium (Mg) alloy. Mesoporous silica nanocontainers (MSN) encapsulated with sodium benzoate (SB) corrosion inhibitors were strategically incorporated in the MAO micropores and in the top EP layer. The influence of the strategic positioning of the nanocontainers on the corrosion protective performance of coating was investigated. The experimental results and analysis indicated that the superior corrosion resistance of the hybrid coating is ascribed to the protection mechanisms of the nanocontainers. This involves two phenomena: (1) the presence of the nanocontainers in the MAO micropores decreased the distance between MSN@SB and the substrate, demonstrating a low admittance value (∼ 5.18 × 10−8 Ω−1), and thus exhibiting significant corrosion inhibition and self-healing function; and (2) the addition of nanocontainers in the top EP layer densified the coating via sealing of the inherent defects, and hence the coating maintained higher resistance even after 90 days of immersion (1.13 × 1010 Ω cm2). However, the possibility of corrosion inhibitors located away from the substrate transport to the substrate is reduced, reducing its effective utilization rate. This work demonstrates the importance of the positioning of nanocontainers in the coating for enhanced corrosion resistance, and thereby providing a novel perspective for the design of smart protective coatings through regulating the distribution of nanocontainers in the coatings.

In this work, polypyrrole-based nanocomposites doped with graphene oxide, molybdate, and salicylate (PPy/GO/Mo/Sal) were synthesized via in situ electrochemical polymerization to enhance the anti-corrosion protection performance of polymer coatings. The morphology and structures of the coatings were characterized by SEM, EDX, FTIR, Raman spectroscopy, and XRD. The protection abilities of coatings against corrosion were investigated in 0.1 M NaCl solution with EIS potentiodynamic polarization, salt spray test, and open-circuit potential (OCP) measurements. The results showed that with the presence of both molybdate/salicylate and GO in the PPy matrix, the nanocomposite coating exhibited an excellent protection ability against corrosion for low-carbon steel, better than that with only GO as filler. Compared to the nanocomposites doped with only salicylate or salicylate/GO, the one doped with both molybdate/salicylate and GO exhibited the longest protection plateau (ca. 100 h) on the OCP-time curves with some fluctuation points known as the self-healing action of molybdate dopant. It also resulted in a decrease in the corrosion current (Tafel plots), a higher impedance (Bode plot), and a better protection performance in salt spray tests. In this case, the anti-corrosion ability of the coatings was provided through a barrier and self-healing mechanism.

Featuring low density and high specific strength, magnesium (Mg) alloys have attracted wide interests in the fields of portable devices and automotive industry. However, the active chemical and electrochemical properties make them susceptible to corrosion in humid, seawater, soil, and chemical medium. Various strategies have revealed certain merits of protecting Mg alloys. Therein, engineering self-repairing coatings is considered as an effective strategy, because they can enable the timely repair for damaged areas, which brings about long-term protection for Mg alloys. In this review, self-repairing coatings on Mg alloys are summarized from two aspects, namely shape restoring coatings and function restoring coatings. Shape restoring coatings benefit for swelling, shrinking, or reassociating reversible chemical bonds to return to the original state and morphology when coatings broken; function self-repairing coatings depend on the release of inhibitors to generate new passive layers on the damaged areas. With the advancement of coating research and to fulfill the demanding requirements of applications, it is an inevitable trend to develop coatings that can integrate multiple functions (such as stimulus response, self-repairing, corrosion warning, and so on). As a novel carrier and barrier, porous solids, especially covalent organic frameworks (COFs), have been respected as the future development of self-repairing coatings on Mg alloys, due to their unique, diverse structures and adjustable functions.

The purpose of this study is to investigate the indirect effects on the properties of ZrO2 films deposited by atomic layer deposition (ALD) when an Mg-Ca alloy is modified through equal-channel angular pressing (ECAP) following extrusion. The study aims to understand how the increase in CaO content in the native oxide layer of the Mg-Ca alloy influences the crystallinity and defect density of the ZrO2 film. Consequently, the corrosion protection performance of the ZrO2 film is enhanced by 1.2 to 1.5 times. A reduction in the anti-scratch property of the ZrO2 film was also observed, with a critical load reduction of 34 μN. This research provides a detailed analysis of the modifications induced by ECAP on the as-extruded Mg-Ca alloy and its subsequent impact on the properties of the ZrO2 film.

Introduction. The article deals with the actual issues of application of traditional and innovative technologies in teaching students of construction specialities in Priazovsk State Technical University (PSTU). The peculiarities of integration of specialized civil engineering education and a wide range of directions of university education are analyzed. The infrastructure of competence-based approach to motivate professional, scientific and career development of construction personnel is proposed. The necessity of expanding the interaction of educational, industry, scientific and public organizations and business for successful implementation of the tasks of technological development of the building industry is shown.Materials and methods. The epistemological essence of modern technological development in the conditions of post-industrial society is analyzed. On the basis of the historical-systemic method, the interdependence of traditions and innovations in the sphere of technical and economic interaction between education, architecture and construction is considered. Spatial and temporal characteristics of continuity conditions in the process of personally oriented education in the field of construction are presented. The tasks of programme-targeted management of creative and innovative potential in the interests of restoration, technological modernization and reconstruction of the industrial complex of Donbass are formulated.Results. Practical results of the research and development carried out on the basis of scientific, educational and industrial cooperation on the problem of technological safety and corrosion protection of industrial facilities are systematized. The priorities of interaction between the elements of the “science – education – business” infrastructure model, as well as transformation of corporate knowledge into educational programmes and postgraduate continuing education are revealed. The prospect of activity of “Tekhnoresurs” Scientific and Educational Centre in the development of pilot projects to promote of digital technologies of technological safety management of industrial facilities is substantiated.Conclusions. It is proposed to implement educational programmes and scientific research in the field of construction based on the principles of programme-targeted management. The problem of resource, reliability and safety of construction facilities requires the analysis of regional conditions of industrial and technological development of Donbass. The infrastructure model, balanced on the basis of interrelation of traditions and innovations, provides the competence approach of personality-oriented continuing education in the field of construction. The directions of deepening the knowledge of PSTU students in the field of construction, with account for the existing practice of managing technological safety of industrial facilities.

Recently, new surface treatments for the corrosion protection of Al alloys by forming self-healing layers have attracted the attention of many researchers. The authors of this paper have previously developed self-healing polyurethane coatings with micro-capsules containing healing agents and porous anodic oxide films filled with healing agents. In this study, self-healing coatings consisting of an outer electrodeposited epoxy resin layer and an inner porous anodic oxide layer with healing agents were developed for the corrosion protection of Al alloys. The corrosion protection abilities of the self-healing coating were shown in Cu2+/Cl− solutions after damaging with indenters and were affected by freezing treatments and the tip angles of the indenter.

Sulphuric acid (H2SO4) is widely used in various industrial processes, including fertilizer production. However, its highly corrosive nature poses a significant challenge to the materials used for transport and storage, particularly metals and alloys. This review provides an overview of corrosion types in iron and nickel-based alloys, commonly employed for handling sulphuric acid. The paper discusses alloy selection based on their corrosion behavior in different H2SO4 concentrations, temperatures, and harsh conditions such as erosion-corrosion and presence of contaminants. Additionally, it highlights the use of inhibitors and polymeric coatings for corrosion protection. Finally, the paper outlines future research directions for corrosion protection of alloys in sulphuric acid environments.

The poor anticorrosion property of magnesium alloys is one of main concerns prior to their various applications. In this study, an anticorrosive hydrogen phosphate coating was fabricated via the ultrasound-assisted chemical conversion treatment on AZ41 Mg alloy for concrete formwork. The coatings prepared by the conventional chemical conversion and hydrothermal treatment were also obtained as a comparison. Surface characterizations and electrochemical methods were carried out. Results show that the ultrasound-assisted coating obtained possesses a thickness more than 3 μm, which is thicker than the other two coatings. Moreover, the ultrasound-assisted coating presents a more homogeneous structure on the second phases, while the surface qualities of the other two coatings were significantly reduced due to the inhomogeneous CaHPO4·2H2O (DCPD) formed on the second phases in AZ41 Mg alloy. The ultrasound-assisted chemical conversion coating exhibits a good corrosion resistance even comparable to the hydrothermal coating. It exhibits a corrosion current density on the order of magnitude of 10−7 A·cm−2 even after the embedment of 96 h in the Portland cement (PC) system containing 3.5 wt% NaCl.

Coating technologies are a commonly used way to protect metals against corrosion. However, with more and more severe service environments of materials, many protective coating systems often are not environmentally friendly or toxic as in the case of chromates. Based on the world's abundant ideal magnesium (Mg) and its alloy, the smart self-healing anticorrosive coating can autonomously restore the damaged part of the coating according to the environmental changes, strengthen the corrosion protection ability, and prolong its service life. This paper reviews the research progress of smart self-healing coatings on Mg alloys. These coatings mostly contain suitable corrosion inhibitors encapsulated into micro/nano containers. Moreover, the different self-healing mechanisms and functionalities of micro/nano containers are discussed. The micro/nano containers range from inorganic nanocontainers such as mesoporous nanoparticles (silica (SiO2), titanium dioxide (TiO2), etc.), over inorganic clays (halloysite, hydrotalcite-like, zeolite), to organic nanocontainers such as polymer microcapsules, nanofibers, chitosan (CS) and cyclodextrin (CD), as well as, carbon materials such as graphene and carbon nanotubes and hybrids such as metal organic frameworks. The functioning of micro/nano containers can be divided in two principal groups: autonomous (based on defect filling and corrosion inhibition) and non-autonomous (based on dynamic bonds and shape memory polymers). Moreover, multi functionalities and composite applications of various micro/nano containers are summarized. At present, significant progress has been made in the preparation methods and technologies of micro/nano containers. Achieving long-term self-healing properties of coatings sensing of coating failure and early warning after self-healing function failure can be expected as the main development direction of self-healing corrosion protection coatings in the future.

An anticorrosive CaCO3/MgO coating was obtained on AZ41 Mg alloy via rapid electrochemical deposition for the application of concrete formwork. Surface characterizations were carried out to obtain the morphology and chemical composition of the coating. Afterwards, long-term anticorrosion performance was investigated via electrochemical methods in the chloride-containing Portland cement system. Results show that the electrochemical deposited coating consists of an outer CaCO3 layer and a compact inner MgO layer. Pre-immersion in the electrochemical deposition electrolyte contributed to the formation of a dense coating. The pretreatment plays an active role in the formation of an inner MgO layer, which significantly enhanced the binding between outer CaCO3 layer and Mg substrate. The electrochemical deposited CaCO3/MgO coating with pretreatment shows improved anticorrosion property than the coating without pretreatment, which could be ascribed to the formation of the dual-layer structure. Additionally, corrosion mechanism is suggested and discussed for the CaCO3/MgO coating.

In this study, a simple in-situ preparation method for coating on Mg-Zn alloy in a carbonic acid solution was investigated. The formation of a precursor carbonate layer on the alloy surface was observed. As the soaking time increased, the solution gradually turned alkaline, leading to the transformation of the precursor into a basic carbonate coating with a layered hydroxide structure. The corrosion potential (Ecorr) of the coated samples initially decreased and then increased with increasing the soaking time. After 2 h of soaking, the lowest corrosion potential observed was approximately −1.5105 V. At 12 h, the corrosion potential reached around −1.4645 V, which was comparable to that of the ZK61M magnesium alloy. After 48 h, the corrosion potential was measured to be approximately −1.3507 V.

The failure of a titanium implant is often attributed to inflammatory reactions following implantation. This study focuses on the synthesis of a polyethylene glycol (PEG) layer on porous titanium dioxide (TiO2) coatings using plasma electrolytic oxidation (PEO). This PEG layer serves as a foundation for a drug-eluting platform designed to respond to pH stimuli during inflammation. Betamethasone (BET), a widely used anti-inflammatory drug, was loaded onto the pH-responsive functional PEG layers. The application of the PEG-BET layer onto TiO2 coatings through the vacuum dip coating method resulted in a pH-sensitive sustained release of BET over a 30-day period. Notably, the release rates were 81% at pH 5.0 and 55% at pH 7.2. Electrochemical corrosion tests conducted in both normal and acidic inflammatory solutions demonstrated that duplex composite coatings offer superior protection compared to simple oxide coatings. In a pH 5.0 solution, corrosion current density measurements revealed values of 1.75 μA cm−2 (PEO/PEG-BET), 8.87 μA cm−2 (PEO), and 49.17 μA cm−2 (bare titanium). These results highlight the effectiveness of the PEO/PEG-BET layer in sealing pores within PEO coatings, subsequently reducing the infiltration of corrosive ions in inflammatory environments.

This study investigates the potential of utilizing reduced graphene nanosheets to enhance the anticorrosion properties of MnO2 coatings. Specifically, the study focuses on the incorporation of reduced graphene oxide (rGO) into MnO2 coatings to improve their anticorrosion performance. The MnO2-decorated graphene oxide nanocomposite (MnO2@rGO) was thoroughly characterized using various analytical techniques, including Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). These analyses elucidated the morphological and structural features of both rGO and MnO2, highlighting the chemical bonding between MnO2 and rGO. Furthermore, the MnO2@rGO nanocomposite underwent additional modification with glycidoxypropyltrimethoxysilane (GTA) before integration into the epoxy resin, resulting in the formation of the epoxy coating (MnO2@rGO/EP-GTA) on steel plates. Electrochemical and potentiometric measurements demonstrated that the inclusion of rGO significantly prolonged the cathodic protection duration of MnO2 within the coatings. This enhancement can be attributed to rGO acting as an impermeable barrier within the coating matrix, thereby enhancing electrical conductivity and facilitating efficient electrical connection between manganese oxide particles and the steel substrate. Additionally, the incorporation of MnO2@rGO and GTA modification led to improved performance of the MnO2@rGO/EP nanocoating, including enhanced resistance to UV aging and salt spraying, effective dispersion of the MnO2@rGO nanocomposite within the epoxy resin, and increased cross-linking density and adhesion strength of the epoxy coating.

Introduction. A review of studies on the protection of threaded connections from corrosion shows that they have leaks that contribute to the development of crevice corrosion, which leads to a decrease in the mechanical strength of threaded connections and complicates dismantling. Modern lubricants and chemical thread fixatives do not provide corrosion protection and disassembly of threaded connections over a long service life, so the development of a more effective lubricant composition is an urgent task. Aim of the Article. Is to develop an effective lubricant composition to protect against corrosion and improve the disassembly of threaded connections. Materials and Methods. The parts of the M10 threaded pair with a thread pitch of 1.5 mm made of St3 steel, connecting two products, (prototypes) were lubricated with grease Zh-SKa 2/6-2, lithol-24, grease + oligomer D-10TM 5% by weight, composition of litol-24 + oligomer D-10TM 5% by weight, tightened to the moment of tightening force 80 N‧m, immersed in a 3% hydrochloric acid solution at a temperature of 22‒24°С. After 8 hours, the samples were removed from the solution and left in the air for 16 hours, which represented one cycle. According to the lubrication options, the number of parallel experiments was 5. Exposure duration – 24; 48; 96; 240; 480; 720 hours, after the expiration of which 5 samples of each lubricant option were disassembled, the value of the moment of the release force was recorded, the corrosion damage was assessed, and the coefficient of friction was calculated. Results An effective lubricant composition has been developed for processing parts of threaded connections, which increases their corrosion resistance and improves dismantling. Discussion and Conclusion. When adding oligomer D-10TM 5% by weight in litol-24, there is a significant increase in the length of time before the appearance of foci of corrosion on the details of threaded connections and an improvement in their dismantling. Implementation of the obtained results allows to increase the reliability of threaded connections.

Halloysite nanotubes (HNTs) and their modifications with either NH2 (HNT-NH2) or NH2/Polypyrrole (HNT–NH2–PPy) were electroless-deposited into the NiP matrix for the first time to form NiP/HNT, NiP/HNT-NH2 and NiP/HNT–NH2–PPy nanocomposite coatings. The as-prepared nanocomposite coatings were heat-treated at 400 °C for 1 h. The transformation in microstructure, nanoindentation, Vicker's micro-hardness, surface morphology, and anti-corrosive properties of all prepared composite coatings were compared to the HNT-free (NiP) coating. Incorporating HNTs in the NiP coating made an appreciable enhancement in the hardness and corrosion resistance. Using the electrochemical impedance spectroscopy technique (EIS), the NiP/HNT-NH2 and NiP/HNT–NH2–PPy coatings showed more significant levels of enhancement in anticorrosion performance, offering about 16.5% and 25.4%, respectively, an increase in the inhibition efficiency of unmodified one (NiP/HNT), reached to 73 and 82%. Moreover, the modified HNT coatings revealed slightly high levels of betterment in microhardness, about 9% and 5.4% for HNT modification with NH2 and NH2-PPy, respectively. In addition, the heat treatment extra improved the hardness and the corrosion resistance of all HNTs nanocomposite coatings compared to HNT-free coating. Furthermore, the heat-treated NiP/HNT has the highest protection efficiency reached to about 95%, based on the polarization measurements. This momentous improvement in the hardness and electrochemical properties reflects the effect of adding the pristine and the modified HNTs into the NiP matrix, resulting in the development of high-performance NiP/HNT-NH2 and NiP/HNT–NH2–PPy composite coatings facilitating their use in various industries.

Hydrophobic coatings from chitosan–surfactant composites (ca. 400 nm thick by UV-Vis spectroscopy) for possible corrosion protection were developed on glass and zinc substrates. The surfactants (sodium dodecyl sulfate, SDS or sodium dodecylbenzenesulfonate, and SDBS) were added to the chitosan by two methods: mixing the surfactants with the aqueous chitosan solutions before film deposition or impregnating the deposited chitosan films with surfactants from their aqueous solutions. For the mixed coatings, it was found that the lower surface tension of solutions (40–45 mN/m) corresponded to more hydrophobic (80–90°) coatings in every case. The hydrophobicity of the impregnated coatings was especially significant (88° for SDS and 100° for SDBS). Atomic force microscopy studies revealed a slight increase in roughness (max 1.005) for the most hydrophobic coatings. The accumulation of surfactants in the layer was only significant (0.8–1.0 sulfur atomic %) in the impregnated samples according to X-ray photoelectron spectroscopy. Polarization and electron impedance spectroscopy tests confirmed better barrier properties for these samples (40–50% pseudo-porosity instead of 94%). The degree of swelling in a water vapor atmosphere was significantly lower in the case of the impregnated coatings (ca. 25%) than that of the native ones (ca. 75%), measured by spectroscopic ellipsometry. Accordingly, good barrier layer properties require advantageous bulk properties in addition to surface hydrophobicity.

Magnesium alloys, because of their excellent strength-to-weight ratio, are increasingly used in many industries. When used in external elements, the key factor is to provide adequate anticorrosion protection. High-temperature, cured-powder coatings are widely used to protect most metals, but their use on magnesium alloys is difficult as a result of the instability of the magnesium substrate at elevated temperatures. Another problem is ensuring the proper adhesion of the organic coating to the magnesium substrate. This paper presents the procedure for the synthesis of a duplex coating on AZ91 magnesium alloy. The topcoat was a powder coating based on acrylic resin, the main ingredient of which was glycidyl methacrylate. Because of the presence of epoxy groups, the coating was cured using ultraviolet (UV) radiation (low-temperature technology). The conversion subcoating was produced by plasma electrolytic oxidation (PEO) in an alkaline silicate electrolyte. The synthesized coating system was tested, among others, for microscopic (SEM), adhesive (mesh of cuts), and anticorrosion (EIS). The duplex PEO/UV-curable powder coating showed very good adhesion to the metal and increased the anticorrosion properties of the magnesium substrate, compared to the powder coating produced directly on the magnesium alloy and on an alternative conversion coating (synthesized in the process of chemical zircon phosphating).

In our previous work, the effect of Gd alloying on the oxidation resistance of AZ80 alloy was revealed briefly. However, a comprehensive understanding of the oxidation and corrosion resistance of the oxide layer formed on the Gd alloying AZ80 alloy surface needs to be developed. Thus, in this research, the high-temperature oxidation behaviors, oxidation products, and oxide layer characteristics of AZ80, AZ80-0.47Gd, and AZ80-0.75Gd (wt%) alloys were investigated at 420 °C. The corrosion protection of the oxide layer formed on the alloy surface was evaluated. The results showed that Gd alloying eliminated the content of the low melting point phase of β-Mg17Al12 and promoted the generation of a high melting point phase of Al2Gd. Gd2O3 appeared in the oxide layer and facilitated the propagation of homogeneous oxidation as well as densification of the oxide layer. In addition, the firm oxide layer showed characteristics of a blurred boundary with the magnesium matrix. After immersion of the oxide layer containing gadolinium oxide, the products of corrosion were massively nodulated, leading to the passivation of corrosion. This research provides new ideas for magnesium alloy protective layer preparation via a high-temperature oxidation technique.

Waterborne epoxy coating is an environmentally friendly anticorrosion coating that are gradually attracting people's attention. However, the anticorrosion performance of waterborne epoxy coatings is unsatisfactory. It is found that the incorporation of some nanomaterials can remarkably improve the anticorrosion properties of waterborne epoxy coatings. This study reports an environmental-friendly waterborne epoxy (EP) coating with enhanced corrosion protection performance by embedding prepared octadecylamine-attapulgite-graphene (ODA-ATP-G) nanocomposite. By the analysis of electrochemical impedance spectroscopy (EIS), it is found that ODA-ATP-G nanocomposites can significantly improve the corrosion resistance of waterborne epoxy coating and provide long-time corrosion protection for the steel substrate. Through the analysis of UV–Visible Near Infrared Spectrophotometer, SEM, EDS and Raman, it is demonstrated that the reinforcement effect of ODA-ATP-G nanocomposites should be attributed to the barrier effect of ODA-ATP-G nanocomposite, the formation of hydrophobic protective film on the steel surface with the adsorption and deposition of ODA.

Herein, novel microcapsules were designed and synthesized by emulsion polymerization and used for self-healing coating for magnesium alloy. Polyaniline (PANI) was used directly as a capsule shell, and thermoplastic acrylic resin was used as the core material. Polymerization processes of microcapsules were observed by optical microscopy, and some key polymerization parameters were discussed. Composite microcapsules were analyzed by scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis. The corrosion protection performance of microcapsule and epoxy varnish coatings with defect was tested by electrochemical impedance spectroscopy. Results showed that the microcapsule coating had a higher corrosion protection than epoxy varnish coating because capsule core acrylic resin could significantly improve the shield performance of the defect coating and capsule shell PANI could inhibit the corrosion reaction of magnesium alloy.

In order to explore the corrosion mechanism of galvanized Al-Mg steel plate coated with chromium-free passive solution and anti-rust oil in the transportation environment，XPS and EDS were used to analyze the element differences in the color-difference zone.The microstructure of chromium-free passive film of the galvanized sheet before and after corrosion was investigated by atomic force microscope.Raman spectroscopy was used to analyze the curing mechanism and protection process of coated chromium-free passivator.Results showed that the reaction between the components of antirust oil and passive film affected the antirust performance of the coating film.Raman spectrum revealed that the cured plate could be cured more completely by increasing the temperature to 90 ℃，and the anti-rust ability was obviously enhanced.

Organic inhibitors provide advantages for corrosion protection through formation of chelation layers. However, individual inhibitors have weak inhibition efficiency when they are exposed to neutral media containing chloride ions. In this study, corrosion resistance of Mg alloy AZ91D is synergistically enhanced by combining green chicory (CA) extracts with metal cations (Ca2+, Fe3+, Fe2+, and Ni2+). The Mg(OH)2 and MgO corrosion products are porous in the early stages of immersion. The main organic compounds in CA including caffeic acid (Caf) and chicoric acid (Chi), which combine with inorganic cations via chelation reaction, are adsorbed on the corroded area. The large Bader charge and adsorption energies of Chi-Calcium-Chi (CaChi) complexes determined through density functional theory calculations suggest that CaChi interacts strongly with inorganic cations. The combined organic–inorganic inhibitors can therefore be absorbed firmly on the Mg substrate to form an active inhibitory layer. Among the various investigated CA-cation mixtures, CA-Ca2+ exhibited the highest anti-corrosion effect after immersion for 120 h and a corrosion current density (icorr), corrosion potential (Ecorr), and inhibition efficiency (η) of 0.09 ± 0.03 μA·cm−2, –0.87 ± 0.03 V (vs. SCE), and 92%, respectively. This work provides an effective approach for corrosion protection through combination of organic and inorganic inhibitors.

Finding new cost-effective and environmentally friendly anti-corrosion materials is a never-ending task. Herein, the main objective is to prepare a new formulation based on piroxicam-cyclodextrin inclusion complex (PX@β-CD) as an efficient green inhibitor to protect mild steel against corrosion in 1 M HCl. The inhibition performance of PX@β-CD was determined by electrochemical tests coupled with theoretical study like as DFT calculation to assess the reactivity and interaction mechanisms between PX@β-CD and Fe. The obtained results revealed that PX@β-CD performs excellently inhibition performance where its inhibition efficiency reached 98.65% at 0.4 mM, and it acted as a mixed type inhibitor with anodic predominance. SEM and contact angle analysis showed the formation of compact PX@β-CD film on steel surface. The adsorption of PX@β-CD inhibitor followed the Langmuir adsorption model according to the gravimetric corrosion measurement. Thermodynamic analysis and DFT calculations revealed the chemisorption of the inhibitors on the steel surface.

Due to its numerous potential applications, molybdenum disulfide (MoS2; moly), one of the newly developing transition metals dichalcogenides (TMDCs), has exceptionally drawn high interest. Particularly in solution-based applications, MoS2 has potential that has not yet been completely realized. The structural and morphological characteristics of MoS2 films prepared by two diverse approaches for example chemical vapor deposition (moly/CVD) and autoclave (moly/AC) methods were investigated by scanning electron microscopy supported by energy dispersive X-ray spectroscopy (SEM/EDX), FTIR, transmission scanning microscopy (TEM) and X-ray diffraction (XRD). The anti-corrosive performance of the uncoated and coated steel was investigated in 1.0 M HCl. Electrochemical tools such as electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) were completed to measure the corrosion protection properties. The moly/CVD and moly/AC coated 5-layer steel substrates showed a protection capability of 94.2 and 98.2%, respectively. The effect of the synthetic strategy and the film thickness on the corrosion characteristics was examined. Before and after exposure to the corrosive solution, the surface morphology of the uncoated and coated steel specimens was described using SEM. These MoS2 thin films are a new and cost-effective alternative to improve steel corrosion resistance and could be used to protect steel in environments with chloride acidic medium due to their unique physicochemical properties.

Carbon and oxygen-rich corrosion barrier layer formed on Mg by a simple and scalable CO2 atmospheric plasma (CO2-AP) process. The reactive CO2-AP interacts with the Mg surface and forms a unique layered structure with the top MgCO3/MgO-intermixed particulates pillars and the bottom dense layer. The surface features were simultaneously formed on the nano-/micro-structured MgO layer by carbonate molecules, plasma-active CO2 molecules, and/or other volatile organic compounds on the nano-/micro-structured MgO particle layer. The resulting surfaces after CO2-AP were either hydrophobic or hydrophilic and exhibited lower anodic current or high resistance for Mg corrosion. For the hydrophobic surfaces of CO2-AP treated Mg, molecular dynamic simulations were performed to understand the origin of hydrophobicity and identified that the amorphous carbon layers formed on the Mg surface are the source. The environmentally benign abundant-gas-based process enables the cost reduction associated with waste treatment, generation of by-product, and supply of raw material.

In this article, environmentally friendly alkyd coatings with different nanosilica content (0-2.0 weight percent (wt%) were prepared for improving some properties as mechanical properties, corrosion protection, thermal resistance, etc. Nanosilica in coating was characterized by FT-IR. Effects of nanosilica on mechanical properties of environmentally friendly alkyd coatings with and without nanosilica such as adhesion, flexural strength and relative hardness and thermal stability were investigated. Coatings with and without nanosilica was also investigated with salt mist testing. Nanosilica with content of 1.5 wt% significantly improved mechanical properties, corrosion resistance, thermal oxidation resistance of environmentally friendly alkyd coatings.

The problem of selecting a method for ensuring the reliability of the unprepared fluid transport facilities of an unprepared fluid in the presence of carbon dioxide is considered. Carbon dioxide corrosion is one of the dangerous types of damage to field and main pipelines. It has been shown that dynamic autoclave tests should be carried out during staged laboratory tests in order to determine the intensity of carbon dioxide corrosion and to select the optimal method of protection. A hypothesis about the imperfection of the existing generally accepted approaches to dynamic corrosion testing has been put forward and confirmed. A test procedure based on the use of an autoclave with an overhead stirrer, developed using elements of mathematical modeling, is proposed. The flows created in the autoclave provide corrosive wear of the sample surface similar to the internal surfaces elements wear of the pipelines piping of gas condensate wells. The autoclave makes it possible to simulate the effect of the organic phase on the flow rate and the nature of corrosion damage to the metal surface, as well as the effect of the stirrer rotation speed and, accordingly, the shear stress of the cross section on the corrosion rate in the presence/absence of a corrosion inhibitor. The given results of staged tests make it possible to judge the high efficiency of the developed test procedure.

Layered double hydroxide (LDH) coatings emerge as a sound strategy to mitigate corrosion of magnesium (Mg) alloys owing to their unique anion-exchange capability to entrapping aggressive anions, such as chloride. The most common approach for fabricating protective LDH coatings upon the surface of Mg alloys is hydrothermal treatment, which is ascribed to their simple manipulation, rich diversity in chemistry and structure of resultants, and high coating adhesion via chemical bonding. This article reviews the roles of key processing variables of hydrothermal manufacturing of LDH coatings to provide insights for design and optimising LDH coatings with satisfactory corrosion protection to Mg alloys. The selected key variables include chemistry and microstructure of Mg alloy substrate, components of LDH solution, hydrothermal operational conditions (mainly involving solution pH, reaction temperature and reaction time duration), and anionic types used in post anion-exchange treatment. The contributions of those variables to the growth behavior of LDH coatings are discussed. The relationships between LDH coating structure and its corrosion mitigation are also established. Finally, the strength and limitations of existing work are critically articulated and future research directions are proposed accordingly.

In the present work, we studied whether the exposure of synthetic seawater with anaerobic sulphate-reducing bacteria (SRB) on some steel samples generates a bacterial biofilm in their surfaces. Bare steel belonging to a mooring chain as well as two coating systems applied on the steel surface were studied: polyurethane (PU) and thermally sprayed aluminium (TSA) with and without an epoxy-based sealant. After 30 days of immersion in SRB-inoculated synthetic seawater, a bacterial count was attained, and the samples were observed using scanning electron microscopy (SEM) and locally analysed using X-ray scattered energy spectroscopy (EDS). A biofilm developed on every tested surface (continuous or in the form of pustules), with evidence of metabolic activity of the SRB. Finally, a mechanism of degradation for TSA in the presence of SRB is proposed for environments with a high concentration of bacteria.

In this work, phytic acid (PA) and 3-mercaptopropyltrimethoxysilane (MPTS) underwent a condensation process to produce a phytic acid–silane (abbreviated PAS) passivation solution. Additionally, it was applied to the surface of cold-rolled steel to create a composite phytic acid–silane film. The functional groups of the passivation solution were analyzed by Fourier transform infrared spectroscopy (FT-IR). The composite film was evaluated using an electrochemical workstation, scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS) and pull-off test. These techniques allowed for the characterization of the film’s micromorphology, oxidation, chemical composition and adhesion strength. The results show that the PAS composite film provides higher protection efficiency compared to cold-rolled steel substrates, low phosphorus passivation films, single phytate passivation films and commercial phosphate films. This composite film also has a higher adhesion strength, which is beneficial for subsequent coating, and a possible corrosion resistance mechanism was proposed as well. The PAS layer successfully prevents the penetration of corrosive media into the cold-rolled steel surface utilizing P–O–Fe bonds, thus improving the corrosion barrier effect of the substrate.

This study introduces a novel nanocomposite coating composed of PANI/CeO2 nanocomposite films, aimed at addressing corrosion protection needs. Analysis through FTIR spectra and XRD patterns confirms the successful formation of the nanocomposite films. Notably, the PANI/CeO2 nanocomposite films exhibit a hydrophilic nature. The bandgap energy of the PANI composite film is measured to be 3.74 eV, while the introduction of CeO2 NPs into the PANI matrix reduces the bandgap energy to 3.67 eV. Furthermore, the electrical conductivity of the PANI composite film is observed to be 0.40 S·cm−1, with the incorporation of CeO2 NPs leading to an increase in electrical conductivity to 1.07 S·cm−1. To evaluate its efficacy, electrochemical measurements were conducted to assess the corrosion protection performance. Results indicate a high protection efficiency of 92.25% for the PANI/CeO2 nanocomposite film.

Novel modified Zn-Al LDH/epoxy coatings are synthesized and applied to steel substrates, providing active corrosion protection and improved barrier properties. This protective coating is made by combining Epon 828 as a polymer matrix with modified layered-double-hydroxy (LDH) nanoparticles acting as corrosion inhibitor containers. To synthesize the coatings, nitrate was intercalated into Zn-Al-LDH layers through an aqueous co-precipitation method to obtain Zn-Al LDH-NO3, and decavanadate replaced nitrate within the LDH layers through an anion exchange process to obtain Zn-Al LDH-(V10O28)6−. The intercalated LDH was functionalized by silanization with (3-aminopropyl)triethoxysilane (APTES) to increase the compatibility of the LDH inhibitor nanocontainers with epoxy resin and produce a protective coating. To protect the mild steel substrate, functionalized LDH nanopowders were dispersed into the epoxy resin, mixed with a polyamide hardener (Epikure 3571), and applied and cured to the metal surface. Surface morphology, structure, and chemical composition were determined for the modified LDH nanopowders using scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Corrosion protection of the coating system was studied using long-term immersion testing and potentiodynamic polarization studies in a 3.5 wt.% NaCl solution.