Search

Potassium silicate coatings cured by calcium hydrogen phosphate and modified by fillers of Ti and SiO 2 powders were prepared on K447A alloy at 120 °C. The influences of Ti, SiO 2 and both powders on the oxidation behavior of the coated specimens were investigated at 1000 °C for 100 h in static air by thermogravimetry, SEM, XRD and EPMA. The bare K447A alloy suffered severe oxidation at 1000 °C, and the TGO was found to be composited of an outer layer of mixtures of NiCr 2 O 4 , CoAl 2 O 4 and rutile TiO 2 , and an inner α-Al 2 O 3 layer. The potassium silicate coating without filler showed local damages where formation and rapid rupture of bubbles occurred and consequently the local substrate was oxidized. The SiO 2 powder in the coatings is more capable of reducing O diffusion thru the coatings than the Ti powder, while the latter is more effective in getting rid of bubble rupture than the former. Thus, the coating modified by 10 wt% Ti and 20 wt% SiO 2 showed the best protective performance. [ABSTRACT FROM AUTHOR]

Several studies on progressively inhibiting aluminum elements have been conducted in recent years to combat corrosion issues. Aluminum in the HCl medium may also be updated in the coming years. The key to promoting this technology is achieving a reliable inhibitor for aluminum corrosion in the HCl medium. In this study, different electrochemical methods (EIS and polarization) were used on sumac extract to investigate the inhibitory effect of sumac extract (SE) on aluminum corrosion in a 1 M HCl medium at different temperatures. FTIR analysis reveals the presence of nitrogen and oxygen atoms and aromatic rings, which are responsible for the inhibitory effect of SE. The protection of aluminum surface due to SE presence is supported by the study of sample surfaces (FE-SEM and AFM). Surface studies confirmed corroded surfaces with higher roughness in the absence of SE, while SE caused smooth surfaces. The adsorption of this inhibitor on the sample surface follows the Langmuir isotherm. SE adsorption is enhanced with increasing temperature to 308 K, resulting in higher inhibitory effect at this temperature, approved by EIS and polarization test. The highest inhibition of 99% was recorded by both EIS and polarization methods at 308 K in the presence of 200 mg/L SE. [ABSTRACT FROM AUTHOR]

This work shows the utilization of glycyrrhizic acid (GLA) as a corrosion inhibitor for steel within acidic environments. Employing a multifaceted approach, the investigation integrates spectral analysis, thermal testing, electrochemical assessments, surface characterization techniques, and computational modeling to elucidate GLA's mechanisms of corrosion protection. A pivotal finding of this research underscores GLA's capacity to engage with metal surfaces through both physisorption and chemisorption mechanisms, facilitated by its inherent functional groups. Moreover, thermal analysis reveals GLA's robust stability up to temperatures of 170°C, rendering it well suited for applications within moderate-temperature environments. Electrochemical analyses unveil a notable augmentation in charge transfer resistance, escalating from 5.18 to 90.64Ω/cm2, alongside a concomitant reduction in corrosion current density from 15.64 to 0.83μA/cm2, particularly evident at 200mg/L. Surface examinations corroborate the ameliorated state of surfaces treated with GLA, with discernible compositional alterations indicative of efficacious corrosion inhibition. Adsorption studies align with the Langmuir model, suggesting monomolecular adsorption behavior. Thermodynamic scrutiny reveals a spontaneous and endothermic process, with heightened efficacy observed at elevated temperatures. Lastly, the computational model unveils robust interactions between GLA and the metal surface, characterized by interaction energies reaching as low as −2033.91kJ/mol, thus underscoring the stability inherent in the protective layer formed by GLA. [ABSTRACT FROM AUTHOR]

Due to the increase in severe consequences of mild steel corrosion, the development of coatings with improvement in corrosion-resistant properties has become very essential. In this work, benzotriazole (BTA) was encapsulated into halloysite nanotubes (HNTs) for inhibiting the corrosion of mild steel surface. The BTA-encapsulated HNT exhibits pH-responsive properties over a wide range of pH. It was found that a large amount of BTA was released at pH 3 (48 %), followed by pH 7 (30 %) and least in the case of pH 10 (20 %). At neutral pH, a rapid release of BTA was observed during initial exposure, reaching a steady-state later, with no significant release further. A salt immersion test was carried out after immersing mild steel (MS) substrates in BTA-HNT nanopowder dispersion in 3.5 wt% NaCl at different pH. SEM images and EDS maps confirmed that corrosion product formation on MS surface at pH 3 was significantly more with corrosion pits along with HNTs throughout the surface. At pH 7 and 10, corrosion pits were observed with very few halloysite nanotubes on the surface. An optimum amount of BTA is required to inhibit corrosion, excessive release may cause more Cl− ions to penetrate, leading to more corrosion. Electrochemical data also reveals the same trend, where the i corr value was maximum for pH 3 (1.09 × 10−5 A/cm2) > pH 7 (4.74 × 10−6 A/cm2) > pH 10 (3.43 × 10−6 A/cm2). Therefore, results suggest that BTA-encapsulated HNT can be efficiently incorporated into the coating matrix for their controlled release to provide corrosion protection under varying neutral and alkaline marine environments. [Display omitted] [ABSTRACT FROM AUTHOR]

This study investigates a novel solvent-free, UV LED-curable coating as a robust corrosion protection solution for the inner surface of steel pipelines. The properties of the UV-cured film were characterized in terms of reactivity, thermomechanical properties, and adhesion to metal substrates. The coating was applied to the inside steel pipelines and cured using a patented UV LED lamp designed to fit in confined spaces. Finally, electrochemical impedance spectroscopy characterization and an accelerated cyclic electrochemical technique were performed on the coated pipes to study the corrosion protection properties of the coating, both with and without the addition of inorganic fillers. The results were compared to a commercially available thermally cured coating. It was found that the UV-cured coating confers high barrier properties, effectively preventing liquid penetration even under elevated temperature conditions. Furthermore, the corrosion protection performance in harsh environments was comparable to and, in some cases, higher than standard epoxy linings. [ABSTRACT FROM AUTHOR]

The microstructure of the Pb-Ag alloy is vital to its mechanical, corrosion, and electrochemical properties. In this paper, heat preservation mold is used to control the temperature of cast lead alloy, realizing the regulation of the microstructure of Pb-Ag alloy. The effects of the surface microstructure and the Ag distribution on the mechanical, corrosion-resistant, and electrochemical properties of lead alloy are investigated. The results show that the heat preservation treatment effectively enhances the longitudinal tissue uniformity of the alloy and optimizes the distribution of Ag in the alloy. The alloy shows the best comprehensive performance as the heat preservation temperature reaches 50℃ due to the uniform size of the metallographic structure and the most uniformly distributed Ag. The low-temperature heat preservation treatment (12℃) refines the middle and bottom grains of the alloy and enhances the mechanical properties of the alloy. However, the increased uniform grain size and Ag distribution at the longitudinal level of the alloy led to a decrease in the electrochemical properties and corrosion resistance. [ABSTRACT FROM AUTHOR]

Translation abstract Mattensteg, rehabilitation and relocation of a 150 year old frame bridgeAt the existing Mattensteg – a 150 year old riveted truss‐girder steelbridge, a condition survey in 2005 revealed that the local concrete bridge deck was in poor condition. Based on this assessment and the bridge‘s previous service life, it was decided to carry out a comprehensive renovation of the bridge. At the same time, the AWEL (Amt für Abfall, Wasser, Energie und Luft des Kantons Zürich) planned to renew the Platzspitzwehr. In recent years, access for maintenance work on the weir has been via the Platzspitz, as the Mattensteg cannot be used by heavy vehicles. This is unsatisfactory for the park with its protected plane trees. It was therefore decided to build a new service bridge at the site of the Mattensteg for the construction and future maintenance work. However, as the existing Mattensteg is a listed building, the existing old truss bridge was to be retained, moved some 80 m upstream and rebuilt. The reinforcements were riveted analogously to the existing construction. Due to the protected status of the building, the new piers will be built in the original style with stairs. As a result, the footbridge is no longer accessible to cyclists, wheelchair users or maintenance vehicles. The construction costs for the relocation, the construction of the new supports and piers as well as the restoration of the bridge amount to CHF 2.5 mio. [ABSTRACT FROM AUTHOR]

Iron microparticles were coated with polypyrrole in situ during the chemical oxidation of pyrrole with ammonium peroxydisulfate in aqueous medium. A series of hybrid organic/inorganic core–shell materials were prepared with 30–76 wt% iron content. Polypyrrole coating was revealed by scanning electron microscopy, and its molecular structure and completeness were proved by FTIR and Raman spectroscopies. The composites of polypyrrole/carbonyl iron were obtained as powders and characterized with respect to their electrical properties. Their resistivity was monitored by the four-point van der Pauw method under 0.01–10 MPa pressure. In an apparent paradox, the resistivity of composites increased from the units Ω cm for neat polypyrrole to thousands Ω cm for the highest iron content despite the high conductivity of iron. This means that composite conductivity is controlled by the electrical properties of the polypyrrole matrix. The change of sample size during the compression was also recorded and provides a parameter reflecting the mechanical properties of composites. In addition to conductivity, the composites displayed magnetic properties afforded by the presence of iron. The study also illustrates the feasibility of the polypyrrole coating on macroscopic objects, demonstrated by an iron nail, and offers potential application in the corrosion protection of iron. The differences in the morphology of micro- and macroscopic polypyrrole objects are described. [ABSTRACT FROM AUTHOR]

Innovative powder coating system for hydraulic steel construction Unprotected steel corrodes in the atmosphere, water and soil. In order to ensure structural safety and maintain fatigue strength, steel structures of all kinds must be protected from corrosion. Hydraulic steel structures such as locks, gates, canal bridges, ship lifts and water power plants largely characterize our waterways, coastal fortifications and port facilities. They are exposed to a particularly high level of corrosive attack because, in addition to atmospheric influences such as wind and weather, they are particularly affected by water, constant water changes and aggressive substances such as salts and minerals. Since such constructions and buildings usually represent investments of the century, their preservation, use and operational safety over generations is an economic necessity. But it′s not just corrosion that poses a problem for hydraulic steel construction; the formation of biofilms and the growth of algae and mussels can also lead to problems that can even lead to a restriction in the functionality of the systems. The newly developed powder coating system prevents both and thus helps to extend maintenance intervals, increase the lifecycle of steel components in hydraulic steel construction and reduces the lifecycle costs. The new powder coating system thus makes an innovative and sustainable contribution to the preservation of structures in hydraulic steel construction. [ABSTRACT FROM AUTHOR]

In this work, cerium conversion coating (CeCC) was deposited on AZ91D Mg alloy using potentiostatic polarization method combined with phosphate pore‐sealing treatment. Initially, the optimum deposition parameters to obtain a crack‐free surface were found. The characterization of coating revealed the presence of a nodular morphology of cerium oxide deposits. Next, the electrochemical behavior of the coated surface was assessed using potentiodynamic polarization and electrochemical impedance spectroscopy in 3.5 wt% NaCl solution. Based on electrochemical characterization, the coating exhibited a fivefold increase in the charge transfer resistance and a corresponding 76% reduction in corrosion rate, when compared to the bare surface. Furthermore, the conversion coating exhibited improved corrosion resistance when evaluated using the immersion test. Therefore, these findings demonstrate the feasibility of the potentiostatic method for creating nearly crack‐free CeCC on Mg alloys, unlike conventional conversion coatings. Moreover, this approach holds great potential for effectively mitigating the corrosion issues in Mg alloys. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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. [ABSTRACT FROM AUTHOR]

Copyright of Paint & Coatings Industry (0253-4312) is the property of Paint & Coatings Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, a comparative study of the tribological performance of two hard coatings, CrN/TiBN, was conducted for research purposes and industrial applications in food products, particularly for food packaging into cans using the double hermetic sealing process. CrN and TiBN coatings were successfully deposited on a base-cobalt metal substrate of a CoCrW commercial alloy using physical vapor deposition by arc evaporation (AEPVD) technology to improve the tribological properties of the commercial alloy, including wear and corrosion resistance, lower coefficient of friction, and overall durability. This research focuses on conducting scratch and abrasion wear resistance tests in dry conditions; specifically, it pursues to evaluate the wear corrosion properties, known as tribocorrosion performance, on CrN/TiBN hard coatings. The experimental results show that the CrN coating (2.9 μm) is slightly thicker than the TiBN coating (2.7 μm), with a 47 N critical load. It also shows a lower coefficient of friction (CoF) in a dry environment, while the TiBN coating showed total detachment and a high coefficient of friction in a dry environment condition. Tribocorrosion testing in brine aqueous solution indicated that CrN coating shows a high friction coefficient with a higher open circuit potential value (Ecorr), and TiBN shows the lowest corrosion potential (Ecorr) and the lowest friction coefficient. This suggests that CrN could provide better corrosion protection for commercial cobalt alloys and improve tool performance during the food canning process in brine environments. [ABSTRACT FROM AUTHOR]

[Display omitted] • A direct-to-metal (DTM) coating was prepared with long-lasting anti-corrosion performance. • The synergistic effect of dopamine methacrylate and fluorine compounds on corrosion protection was studied. • PUA coatings had great water-repellency, anti-contamination, and transparency properties based on NP-GLIDE structures. Aluminum and its alloys have been widely used in our lives. However, Aluminum and its alloys is prone to corrosion, especially in harsh environment. In recent years, hydrophobic coatings were used in the corrosion protection of metal. But, the low surface tension of resins made them have a worse wettability on metal which had high surface tension, resulting in a worse adhesion of these coatings. Herein, we developed a long-lasting anti-corrosion direct-to-metal polyurethane NP-Glide coating based on the coordination effect of polyphenol and dual cross-linking. In comparative evaluation, the corrosion protection and anti-contamination performances of direct-to-metal polyurethane NP-Glide coating are significantly improved by the introduction of functional monomer dopamine methacrylamide (DMA) and TEMAc-8. The PU coatings with 10 wt% TEMAc-8 possesses high impedance value (|Z| 0.01Hz > 109 Ω•cm2) after 40 days of immersion in 3.5 wt% NaCl solution, exhibiting a great pull-off adhesion both in dry and wet coating, and a long-term anti-corrosion performance for aluminum alloy protection. [ABSTRACT FROM AUTHOR]

The atmospheric corrosion monitoring (ACM) technique has been widely employed to track the real-time corrosion behavior of metal materials. However, limited studies have applied ACM to the corrosion protection properties of organic coatings. This study compared a bare epoxy coating with one containing zinc phosphate corrosion inhibitors, both applied on ACM sensors, to observe their corrosion protection properties over time. Coatings with artificial damage via scratches were exposed to immersion and alternating dry and wet environments, which allowed for monitoring galvanic corrosion currents in real-time. Throughout the corrosion tests, the ACM currents of the zinc phosphate/epoxy coating were considerably lower than those of the blank epoxy coating. The trend in ACM current variations closely matched the results obtained from regular electrochemical tests and surface analysis. This alignment highlights the potential of the ACM technique in evaluating the corrosion protection capabilities of organic coatings. Compared with the blank epoxy coating, the zinc phosphate/epoxy coating showed much-decreased ACM current values that confirmed the effective inhibition of zinc phosphate against steel corrosion beneath the damaged coating. [ABSTRACT FROM AUTHOR]

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.

[Display omitted] • The self-healing and self-sensing coatings were developed based on pH stimuli. • The coating system shows excellent self-healing and self-sensing properties. • The cooperative effect of two inhibitors protects against steel corrosion. • The corrosion sensing ability is from the color change of Phen adsorbed on steel. Polyelectrolyte-encapsulated nanocontainers can effectively respond to changes of pH and thus control the on-demand release of corrosion inhibitors. A pH-responsive release system (Phen-Tpp@MTNs-PDDA) was developed based on the cationic polyelectrolyte poly dimethyl diallyl ammonium chloride (PDDA) encapsulated mesoporous TiO 2 nanocontainers (MTNs) loaded with 1,10-phenanthroline (Phen) and tripolyphosphate ions (Tpp) corrosion inhibitors. The epoxy coating (EP) embedded with Phen-Tpp@MTNs-PDDA (Phen-Tpp@MTNs-PDDA/EP) demonstrates superior self-healing properties and confers long-term protection on the metal substrate through the cooperative effect of Phen and Tpp. Simultaneously, this hybrid coating is endowed with corrosion sensing capability based on the color development originating from the interaction of Phen and carbon steel. This self-healing and corrosion-sensing multifunctional coating provides an effective strategy for the corrosion protection of metals. [ABSTRACT FROM AUTHOR]

Copyright of Paint & Coatings Industry (0253-4312) is the property of Paint & Coatings Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study reports a combined electrochemical method for preparation of a titanium dioxide–suboxide composite with an electrochemically deposited non-continuous platinum layer on the surface, which can be used for cathodic protection of metal structures. Platinum significantly modifies the properties of TiO2, stabilizes the surface, and prevents the formation of a passive non-conductive layer. The coating has significant advantages compared to Ti/Pt, traditionally used for electrochemical protection, as the platinum content in the composite is significantly reduced. Unlike a continuous precious metal layer, this method of composite formation, particularly thermal treatment in an air atmosphere at 5000 C, allows protecting the platinum, which is encapsulated in titanium oxides, and avoiding the creeping passivation typical of traditionally used materials. The surface of the coatings was investigated using X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, and X-ray microanalysis. Studies of the electrocatalytic properties, especially concerning the oxygen evolution reaction, revealed deviations of the Tafel slope from the theoretical value, which is explained by structural heterogeneity and the presence of a semiconductor component. The stability and corrosion resistance of the composites were studied. It was found that the properties remain unchanged even after prolonged exposure to a corrosive environment. [ABSTRACT FROM AUTHOR]

In this study, a series of photocured epoxied films (SAU-0, SAU-5, SAU-10 and SAU-15) were prepared and applied to the galvanized steel surface for corrosion prevention. These photopolymers were synthesized via cationic photopolymerization using Doublecure®1172 as a cationic photoinitiator. To discuss the crosslinking effect in these photopolymers, various amounts of multifunctional epoxy resin (SU-8) were added into the photoinitiating formulations. The photoreactivity, thermal, mechanical, and morphology properties of all photopolymers were investigated. The results demonstrated that the inclusion of SU-8 epoxy resin not only increased the crosslinking density but also did not sacrifice the interfacial interaction with steel. Finally, the potential dynamic polarization curve of the coated film was studied to realize its corrosion protection performance. As a result, the SAU-15 based photopolymer film, containing the highest amount of SU-8, exhibits the best corrosion protection value (PI = 99.2%) under testing with a 3 M NaCl solution. Furthermore, the SAU-15 based sample demonstrated good long-term storage stability, retaining over 96% of its original corrosion protection value under ambient air atmosphere and room temperature conditions after 28 days. Additionally, all the samples were immersed in 3 M NaCl solution and seawater for long-term stability testing. Once again, the SAU-15 based sample exhibited the best stability after being immersed in the testing solution for 28 days. This paper introduces a concept of SU-8 based photopolymer for corrosion protection and aims to provide a comprehensive understanding of the organic photocured layer technique and its potential for anticorrosion performance. [ABSTRACT FROM AUTHOR]

This study aims to quantify the effect of process parameters on the anodizing of Al6061 aluminum. To achieve this, studies on layer thickness, the porosity of the anodized surface, electrochemical techniques, X-ray diffraction, grain size estimation, and statistical analysis were conducted for three different atmospheres (without air, air, and oxygen). Parameter levels were established as follows: temperature (30 °C, 45 °C, and 60 °C), time (20 min, 40 min, and 60 min), electrolyte concentration (0.5 M), voltage (9 V), and current intensity (0.600 A). A 33 experimental design (three factors, three levels) was proposed, and mathematical models were obtained using general factorial design. The experimental design was used to determine the three most important variables in the optimal condition. A total of 27 tests were conducted using sulfuric acid electrolytic solutions, of which 12 samples were selected by the factorial design method, which simultaneously evaluates the effects of factors and their interactions in a single experiment. Measurement of porosity and oxide layer thickness was performed using scanning electron microscopy. The purity of the anodic layer formed was characterized using X-ray diffraction techniques with a vertical goniometer X-ray diffractometer. The electrochemical behavior is presented through potentiodynamic polarization curves for the anodic layer. A general factorial design and an analysis of variance (ANOVA) were conducted to establish the significant factors for layer thickness, grain size, and reaction rate. Finally, the best results and their parameters for each response are presented. [ABSTRACT FROM AUTHOR]

Relevant aspects in the design of modular expansion joints are the high fatigue stress caused by heavy load traffic and the corrosion protection. Currently, corrosion damage is often not limited to the traversable surface. Therefore, more durable expansion joints are highly desirable to extend their service life. The FOSTA research project P1574 resulted from the need for durable expansion joints and thus is aimed at hot‐dip galvanized structures. In this project about 14.000 individual damages on 6.300 modular expansion joints were evaluated, relevant hot‐dip‐galvanizing parameters were investigated and recommendations for hot‐dip galvanizing‐compatible constructions were made. In addition, the fatigue strength of existing constructions has been evaluated with regard to the current and upcoming version of Eurocode 1993‐1‐9. This evaluation will be verified in the course of cyclic tests and numerical investigations. A monitoring concept is to be designed according to the requirements of the modular expansion joints and the corresponding neuralgic points. [ABSTRACT FROM AUTHOR]

This work covers the formation of a passive state for two different alloys used in the aeronautical industry. The aim of this study is to investigate the effectiveness of passivation treatments on 17-7PH and 410 SS (stainless steel) samples, specifically when performed with citric and nitric acid solutions at 49 °C using an immersion time of 90 min and subsequent exposure in 3.5 wt.% NaCl solution. Employing the cyclic potentiodynamic polarization (CPP) technique, the corrosion properties of the passivated material were evaluated according to the ASTM G65-11 standard. A microstructural analysis was performed using scanning electron microscopy (SEM). The passivated layer was characterized via X-ray photoelectron spectroscopy. In the results, the CPP curves showed positive hysteresis, indicating pitting localized corrosion, and 17-7PH steel passivated at 49 °C for 90 min in citric acid exhibited lower corrosion rate values equivalent to ×10−3 mm/year. [ABSTRACT FROM AUTHOR]

Currently used organic coatings for the protection of bronze sculptures have a relatively short lifespan as a consequence of strict requirements of conservation ethics, which limit the selection of coatings. For that reason, enhancement of the corrosion protection level and durability of appropriate coatings is needed. The aim of this work was to examine if corrosion protection of bronze by selected acrylic and polyurethane coatings could be improved by using two phosphonic acids, 16-phosphonohexadecanoic acid (COOH-PA) and 12-aminododecylphosphonic acid (NH2-PA). Electrochemical measurements (linear polarization and electrochemical impedance spectroscopy, EIS) were performed to gain an insight into the influence of these phosphonic acids on the performance of the coatings during a two-week exposure to artificial acid rain and a three-month outdoor exposure. Besides the influence on the corrosion protection level, the influence on the coating adhesion was examined as well. A pull-off test clearly confirmed that the studied phosphonic acids act as adhesion promoters of both polyurethane and acrylic coatings, while electrochemical studies revealed improvements in corrosion protection levels, especially in the case of the acrylic coating Paraloid B72. [ABSTRACT FROM AUTHOR]

The behavior of two polymeric protective paint coatings (epoxy and polyurethane) applied over an epoxy primer coating on steel plates was investigated in this study, focusing on their role in providing anticorrosive protection against various climatic stress factors. Among the numerous climatic factors that can affect the lifetime of anticorrosive coatings, the following were selected for this work: dry heat, UV radiation, humidity, and extreme conditions such as salt fog, marine atmosphere, and alpine atmosphere. The objective was to determine the remaining lifetime of these protective coatings before replacement is needed to prevent damage to the equipment they protect. The behavior of these polymeric materials under the mentioned factors was analyzed based on the variation in the tangent of the dielectric loss angle (tg δ) with frequency. From the interpretation of the experimental results, it was found that the polyurethane paint coating (P2) exhibits superior resistance to climatic degradation compared to the epoxy paint coating (P1). Furthermore, a comparison of tg δ values for the P1 and P2 coatings revealed that the initial (unaged) P2 coating performs better as an insulator (dielectric) than the P1 coating. Comprehensive information is provided to the users of polymeric anticorrosive protection materials, highlighting the extent to which climatic factors can affect the performance of the equipment they protect and determining the appropriate timing for replacing the coatings. [ABSTRACT FROM AUTHOR]

Damages to multilayer organic coating systems due to impact loads can deteriorate the corrosion protection performance of the coatings under offshore exposure. The contribution is concerned with statistical investigations into the effects of load-based and coating-based factors on the protection performance of impinged coating systems for offshore wind power structures. Accelerated cyclic laboratory tests were performed on damaged multilayer coating systems, and the results were statistically analysed. Results of analysis of variance revealed that the effects on the integral corrosion protection performance of the coatings (anticorrosive effect, AE) were dominated by the factor 'load intensity' (impact energy). This factor could explain 34% of all effects. It also was the only significant factor. The load-based factor 'damage area' affected the coating delamination and was extremely significant, but it did not affect the AE. Coating-based factors, namely 'coating system', 'total dry film thickness' and 'pull-off strength', did not deliver effects to AE and were statistically insignificant. The factor 'coating system' was statistically insignificant for delamination and for AE. 'Unknown' effects, not considered in this study, delivered the highest contributions to the regression models (50% to 68%), indicating that additional parameters/factors of the coating systems must be considered when developing impact-resistant coatings. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

CO2 geological utilization and storage (CGUS) is a key technology to achieve carbon neutrality goals. To apply CGUS on a larger scale, the issue of steel corrosion during the process must be addressed to mitigate technological risks. This paper provides an overview of CO2-induced steel corrosion mechanisms and identifies factors that influence corrosion. The impact of CO2 partial pressure, temperature, salinity, pH, impurities, and fluid flow on steel corrosion behavior are also discussed. With the presence of water, the corrosive effect of supercritical CO2 on steel is stronger than that of dissolved CO2 or gaseous CO2. As the temperature increases, the corrosion rate of steel first increases and then decreases. Increasing salinity and decreasing pH lead to an accelerated corrosion rate of steel. Corrosion inhibitors, coatings, and corrosion-resistant alloys are recommended protective measures against CO2-induced corrosion. Compared with coatings, corrosion inhibitors and corrosion-resistant alloys are more commonly used in CGUS projects. Future research directions include further exploration of the mechanisms underlying CO2-induced steel corrosion, clarifying the coupled effects of various environmental factors, and developing corrosion protection technologies under high-pressure and high-concentration CO2 conditions. [ABSTRACT FROM AUTHOR]

Numerous strategies have been developed for the corrosion protection of steel; however, most of them have a significant environmental impact and employ toxic compounds. Tannins are a green and promising solution for sustainable corrosion protection strategies. In this context, this work was focused on natural (condensed and hydrolysable) tannin layers as a possible corrosion protection strategy for carbon steel. The impact of the tannins' dissolution medium (ultrapure water or Phosphate-Buffered Saline), surface pre-treatment (acid pickling or plasma), and deposition technology (dipping or spin coating) on layer homogeneity and adhesion has been evaluated. The effects of these parameters on coating formation, homogeneity, and adhesion have been investigated by means of visual inspections, swabbing, Fourier Transformed Infrared spectroscopy (FTIR), Scanning Electron Microscopy equipped with Energy Dispersive Spectroscopy (SEM-EDS) and tape adhesion tests. Preliminary electrochemical corrosion tests have been performed on the most promising material (carbon steel acid pickled and coated with a hydrolysable tannin solved in water by spin coating) to estimate the protective ability of the developed layers and highlight the main criticisms to be overcome. [ABSTRACT FROM AUTHOR]

Multifunctional composite coatings have been extensively used to protect metal substrates from corrosion. However, the use of ionic liquids (ILs) to modify the micro-arc oxidation/layered double hydroxides (MAO/LDHs) composite coating, to our best knowledge, has not been reported for the corrosion protection on metal substrates. It is thus necessary to prepare the ILs-modified MAO/LDHs composite coatings and understand in depth their corrosion resistance and active anticorrosive mechanism. Herein, a composite coating is constructed by introducing the MgAl-LDH modified by a choline 3-morpholinopropanesulfonate [Ch][MOPS] ionic liquid on an MAO film (CM-LDH/MAO). It is found that the CM-LDH/MAO composite coating shows the optimal corrosion protection on magnesium alloy, with a corrosion current density of 8.38 × 10−10 A cm−2, clearly lower than those of the MAO and LDH/MAO coatings. More importantly, a small pitting appears at the edge of the CM-LDH/MAO film only after long-term exposure of 216 h in 3.5 wt% NaCl solution. Such an improvement of corrosion resistance can be ascribed to the synergetic mechanism including the physical barrier of the composite coating, the self-repairing ability of the LDH nanosheets on the microporous flaws of the MAO film, as well as the formation effect of the Mg-based chelates by the adsorption of the [Ch]+ cations and the re-adsorption of the [MOPS]– anions released from the LDH interlayers. [ABSTRACT FROM AUTHOR]

AbstractIn this study, two 8-hydroxyquinoline derivatives, HAPAQ and EAPAQ, were first synthesized, and their molecular structures were confirmed by 1H and 13C NMR. The effects of HAPAQ and EAPAQ on corrosion processes were investigated using weight loss, electrochemical, and theoretical methods. Overall, the data unmistakably demonstrate that the inhibition performance (η %) increases with an increase as HAPAQ and EAPAQ concentrations rise, peaking at 96.08% (HAPAQ) and 94.37% (EAPAQ) at the optimal concentration (10−3 M) for PPD technology. The two 8-hydroxyquinoline derivatives exhibit inhibitory behavior, as seen by the polarization curve impedance tests; however, they demonstrate that adsorption promotes protective action on metal surfaces, creating a geometric blocking effect and a protective coating that impedes metal breakdown. HAPAQ and EAPAQ's inhibitory efficacy may be reduced by the rising temperature. Furthermore, it adheres to Langmuir’s single-layer adsorption isotherm, and the physisorption and chemisorption mechanisms are linked to the corresponding value of the adsorption energy (ΔGads). Additionally, the MS scanning electron microscope (SEM) has been studied and discussed. The possibility of complex organization between the inhibitor molecules, 8-hydroxyquinoline derivatives (HAPAQ and HAPAQ), and the Fe2+ ions generated during the oxidation process was established by examining the test solutions using UV–visible spectroscopy. Consequently, it is evident from DFT simulations that the surface recovery is dependent on the local reactivity descriptors. The theoretical outcomes derived from DFT are aligned with the findings of the experimental studies. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Anodizing is a well-documented surface treatment that is inserted in a complex protection system against corrosion applied to Al alloys. In the scientific literature, there are many works about this topic, which are concentrated on: (1) anodic aluminum oxide (AAO) growth mechanism; (2) anodized alloys corrosion behavior, or (3) the influence of anodizing parameters on the following steps of corrosion protection of the anodized layer. However, the effect of the microstructure on the AAO formation is not yet well established. This paper aims to review the effect of the microstructure of Al and its alloys on the anodizing process by a historical, statistical, and electrochemical approach, considering the advantages in understanding the influence of intermetallics in this process. Besides, this review brings a comparison among the number of publications and the types of alloys studied by statistical analyses. Finally, it emphasizes the importance of anodizing in the aeronautical industry, in which a great number of studied alloys are applied, mainly the 2XXX (Al-Cu) and 7XXX (Al-Zn) series alloys. [ABSTRACT FROM AUTHOR]

Two bio‐based polybenzoxazine coatings, cardanol/3‐aminopropyltriethoxysilane‐based polybenzoxazine (PC‐aptes) and cardanol/stearylamine‐based polybenzoxazine (PC‐s), were prepared for corrosion protection on mild steel. The structures of polybenzoxazines were characterized by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT‐IR). Due to the presence of long hydrocarbon chains and hydrogen bond networks, the PC‐aptes and PC‐s coatings showed high hydrophobicity, with static water contact angles of 106.0 ± 0.6° and 104.8 ± 1.6°, respectively. It was noted that the silane‐functionalized PC‐aptes coating had a dual‐crosslinked network of polybenzoxazine and polysiloxane, which could effectively inhibit the penetration of corrosive media. The results of electrochemical impedance spectroscopy (EIS) indicated that the PC‐aptes coating with higher crosslinking density exhibited superior corrosion resistance compared to the PC‐s coating. [ABSTRACT FROM AUTHOR]

In this study, we investigated the efficacy of SiOx-doped diamond-like carbon (DLC) films for enhancing the corrosion resistance of raster steel linear scales. The research work highlights the significant role of DLC film materials in enhancing corrosion resistance, making them a promising solution for various industrial applications. The Raman spectroscopy analysis of SiOx-doped DLC films, synthesized via a direct ion beam technique with HMDSO vapor, revealed prominent D and G bands characteristic of amorphous carbon materials, with a high degree of disorder indicated by an ID/IG ratio of 1.85. X-ray diffraction patterns confirmed the amorphous nature of the SiOx-doped DLC films and the minimal impact of the DLC deposition process on the underlying crystalline structure of steel. UV–Vis-NIR reflectance spectra of SiOx-doped DLC on stainless steel demonstrated improvements in the blue wavelength region compared to stainless steel with ripples alone, which is beneficial for applications utilizing blue light. Corrosion tests, including immersion in a 5% salt solution and salt spray testing, showed that SiOx-doped DLC-coated stainless steel exhibited superior corrosion resistance compared to uncoated steel, with no significant signs of corrosion observed after extended exposure. These findings underscore the potential of SiOx-doped DLC coatings to provide long-term corrosion protection and maintain the structural integrity and surface quality of steel components in harsh environments. [ABSTRACT FROM AUTHOR]

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.