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Galvanized steel is a cost-effective and corrosion-resistant material with high strength, making it a popular choice for various engineering applications. In order to investigate the effects of ambient temperature and galvanized layer state on the corrosion of galvanized steel in a high-humidity neutral atmosphere environment, we placed three types of specimens (Q235 steel, undamaged galvanized steel, damaged galvanized steel) in a neutral atmosphere environment with a humidity of 95% at three different temperatures (50 °C, 70 °C, and 90 °C) for testing. The corrosion behavior of specimens under simulated high-temperature and high-humidity conditions was studied using weight changes, macroscopic and microscopic observations, and analysis of the corrosion products of the specimens before and after corrosion. Emphasis was placed on examining the effects of temperature and damage to the galvanized layer on the corrosion rate of the specimens. The findings indicated that damaged galvanized steel retains good corrosion resistance at 50 °C. However, at 70 °C and 90 °C, the damage to the galvanized layer will accelerate the corrosion of the base metal.

Chamber protection is a promising and quickly developing method of vapor-phase protection of metals against atmospheric corrosion by inhibitors. It was shown that chamber treatment with 2-ethylhexanoic acid (EHA) efficiently inhibits the initiation of zinc corrosion. The optimum conditions (temperature and duration) of zinc treatment with vapors of this compound were determined. If these conditions are met, adsorption films of EHA with thicknesses up to 100 nm are formed on the metal surface. It was found that their protective properties increase during the first day as zinc is exposed to air after chamber treatment. The anticorrosive action of adsorption films is due both to the surface being shielded from the corrosive environment and to the inhibition of corrosion processes on the active surface of the metal. Corrosion inhibition was caused by the ability of EHA to convert zinc to the passive state and inhibit its local anionic depassivation.

The atmospheric corrosion of copper exposed in Martinique (Caribbean Sea) for 1 year was reported. This island suffered the stranding of sargassum algae, which decompose and release toxic gases such as hydrogen sulfide (H2S) or ammonia (NH3). Four sites in Martinique (France) more or less impacted by sargassum algae strandings were selected. The corrosion rate was studied via mass loss determination. The morphology and properties of the corrosion products were determined using Scanning Electron Microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The samples were exposed for up to 12 months. The mass loss results after 1-year exposure were from 4.8 µm for the least impacted site to 325 µm for the site most affected by sargassum algae. This very high value proves that the presence of sargassum algae caused a significant degradation of copper. The morphological structures and properties of the corrosion products obtained at the impacted and non-impacted sites differed significantly. In the absence of sargassum algae, classical corrosion products of copper were reported such as Cu2O and Cu2Cl(OH)3. In the sites near the stranding of the sargassum algae, the CuS product is the main corrosion product obtained, but copper hydroxylsulfate is created.

Flexible barriers mitigate geological hazards, relying crucially on wire-ring nets to intercept rockfalls and debris. However, constant exposure to natural environments renders their metal components susceptible to corrosion, affecting the protective efficacy. To investigate the changes in mechanical properties of wire-ring nets resulting from corrosion, the neutral salt spray tests followed by quasi-static tests on uncoated, Zinc-coated, and Galfan-coated high-strength steel wires and wire-rings were conducted. These tests established the correlation between the steel wire's breaking force and its weight loss rate, ultimately facilitating the creation of a pertinent mathematical model. The decline in the breaking force of various types of wire-rings due to corrosion was compared, indicating the influence of corrosion duration, number of winding turns, winding techniques, and coating types on the wire-ring's mechanical performance. Subsequently, the formula for calculating the breaking force of wire-rings in relation to the weight loss rate of the steel wire was derived. Finally, based on the linear relationship between the capacity of single wire-rings and wire-ring nets, a formula was established to estimate the puncturing force of wire-ring nets under different atmospheric corrosion periods. This predictive model provides a basis for the durability design of flexible barrier with different anti-corrosion measures under various atmospheric conditions, and also offers specific insights into maintenance strategy for the existing flexible barriers. • Indoor accelerated corrosion tests and tensile tests on wire-ring were conducted. • Corrosion effect on mechanical performance of the wire-ring net was investigated. • Predictive formulas for capacity decay under atmospheric environment were proposed. • Specific insights into duration design and maintenance strategy were offered. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach to investigate atmospheric corrosion kinetics of carbon steel under multi-droplet conditions. A homemade climate chamber has been developed to accurately control and monitor environmental conditions, including temperature (T) and relative humidity (RH), during exposure. Carbon steel corrosion kinetics are monitored with a custom-designed Electrical Resistance (ER) sensor pair. Savitzky-Golay (S-G) based filtering technique has been used for the corrosion signal processing. In parallel, top-view droplet temporal evolution has been recorded by microscopic imaging and analyzed for both droplet size distribution and the solid-liquid contact angle. The droplet size distribution can typically be described with a power-law form curve. The curve shows a decrease in height and a concurrent expansion in width with progressive drying. The introduction of NaCl into the electrolyte and surface roughness variations have also been identified to substantially influence the carbon steel corrosion rate. A strong correlation between the corrosion rate derived from the ER monitoring method and the RH can be observed. This correlation is further analyzed to incorporate the impact of droplet-based electrolyte conditions. This study offers valuable insights into the development of mechanistic and kinetic prediction models for atmospheric corrosion. [Display omitted] • Atmospheric corrosion of carbon steel is studied under multi-droplet conditions. • Corrosion rate is monitored with a custom-designed electrical resistance track pair. • Droplet-based electrolyte temporal evolution and environmental conditions are monitored. • A strong correlation exists between corrosion rate evolution and relative humidity (RH). • Small variations between corrosion rate evolution and RH relate to droplet distribution. [ABSTRACT FROM AUTHOR]

• Wavelength and intensity of light impact the cathodic current on passive zinc. • The ocp of primer-coated, galvanised steel positively shifts under light exposure. • The flatband-potential controls the photo-contribution to oxygen reduction. • Photo-generated charge-carriers in ZnO may contribute to cathodic delamination. The influence of sunlight on cathodic delamination of polymer-coated, galvanised steel is considered regarding the semiconductor properties of zinc passive layers. Zinc and galvanised steel were studied potentiostatically in O 2 -rich, moderate alkaline electrolyte under UV-, violet and green light. Currents increased instantaneously, intensity- and wavelength-dependant according to the photoeffect. After electrolyte preconditioning of galvanised, pre-treated and coated (6 µm) steel, light positively shifted the open-circuit-potentials (ocp). Mechanistic considerations are provided using Mott-Schottky-plots and Chopped Linear Sweep Voltammetry (CLSV). Under certain conditions, oxygen reduction reaction (ORR) intensification is found and should be considered in future studies of paint adhesion on zinc. [Display omitted] [ABSTRACT FROM AUTHOR]

Utilizing a dedicated micro-sized three-electrode cell, this study systematically investigates early-stage electrochemical properties and corrosion behavior of pure iron under single droplets. Various volumes and NaCl concentrations were considered during the evaporation-driven shape and concentration evolution of single droplets. The measurements disclosed that reducing the droplet size from 5 µL to 1.5 µL at 0.01 M NaCl concentration, increased noise resistance (R n) and polarization resistance (R p) values. However, at 0.1 M and 0.2 M NaCl concentrations, reducing droplet size led to the domination of relatively high chloride ion concentration over oxygen diffusion, resulting in a very low R n and R p, and hence enhanced localized corrosion. [Display omitted] • A new micro-sized three-electrode cell was proposed for atmospheric corrosion monitoring. • Electrochemical noise represented the early-stage corrosion process of iron under various saline single droplets. • Reducing droplet size from 5 µL to 1.5 µL at 0.01 M diminished uniform corrosion detected by increasing all resistance values. • Reducing the droplet size from 5 µL to 1.5 µL at 0.1 M and 0.2 M changed the type of corrosion from uniform to more localized. [ABSTRACT FROM AUTHOR]

Anti-rust oils (ARO) are widely used to inhibit atmospheric corrosion of metal structures, but their degradation mechanisms are unclear, particularly in coastal environments. In this work, we first prepared a kind of ARO made of sodium petroleum sulfonate (SPS) and white oil, then coated the ARO on a mild steel plate to investigate its deterioration process beneath saline water droplets by Quartz crystal microbalance (QCM) and electrochemical mapping techniques. It shows that the SPS concentration is crucial to the ARO inhibition property. When the SPS content is lower than its critical micelle concentration (CMC), saline droplets may intrude the barrier formed by the nonpolar paraffin groups of SPS and then adsorb on the steel surface, resulting in localised corrosion. However, once the SPS content exceeds its CMC, the saline droplets will be emulsified and captured in the oil phase by the reverse micelle effect, thus inhibiting the corrosion of steel substrates. Moreover, the atmospheric corrosion rate of mild steel obeys a power decaying under ARO film. Finally, a capacitive sensor was invented to evaluate the degree of degradation of ARO in situ by dielectric constant measurement. [Display omitted] • EIS and QCM evidenced the emulsification and capture of saline droplets in anti-rust oils. • An electrochemical capacitive sensor was invented to monitor the degradation of ARO. • DFT shows that water molecules reduce the interaction between surfactant and steel surfaces. [ABSTRACT FROM AUTHOR]

[Display omitted] • Developed a system to measure corrosion potential and hydrogen penetration. • It is based on double head scanning Kelvin probe. • Hydrogen penetration by corrosion is likely enhanced in rust layer under wetting conditions. High-strength steels, such as high-strength bolts or steel plates are considerably sensitive to hydrogen embrittlement. Serious safety problems in steel structures are possible, because they are exposed to atmospheric condition containing chloride ions. Embrittlement is induced by hydrogen penetration during atmospheric corrosion. We developed Double-Head Scanning Kelvin Probe (DHSKP) equipment to clarify the relationship between the corrosion process and hydrogen permeation. Each probe can simultaneously measure the corrosion potential on the corroded side and surface potential on the hydrogen-detecting side at the same time. In this study, we investigated the correlation between the corrosion potential and hydrogen permeation under changing conditions from wet to dry processes on the surface of a steel sample. During the drying process, the corrosion potential at the rust layer that precipitated in the early wetting condition showed a less noble potential locally, whereas the surface potential of the Pd film on the hydrogen detection side showed a less noble potential locally. The hydrogen permeation sites were limited to small spots in the opposite area, where the corrosion potential showed a less noble local-potential during the drying process. Hydrogen penetration by corrosion likely occurs in acidic liquids under the rust layer during the drying process. [ABSTRACT FROM AUTHOR]

This study investigates the impact of Ca and Sb elements on the corrosion resistance of E690 steel in a simulated marine environment. Electrochemical testing and dry/wet cyclic corrosion testing were conducted on prepared E690 steel specimens. The eroded specimens’ microstructure was observed under a scanning electron microscope, and the inclusion morphology was analyzed using an energy-dispersive spectrometer (EDS). The simulating liquid was designed to emulate the severe marine atmospheric environment in Xisha. Results showed that the addition of Ca and Sb elements effectively enhances the corrosion resistance of E690 steel in the simulated marine environment. The corrosion rates of E690 steel specimens with Ca and Sb additions were lower than those without, and the corrosion morphology was more uniform. These findings suggest that the addition of Ca and Sb elements can improve the corrosion resistance of E690 steel in simulated marine environments and have potential for use in marine engineering applications.

The automobile industry commonly uses cyclic corrosion tests (CCTs) to evaluate the durability of materials. However, the extended evaluation period required by CCTs can pose challenges in this fast-paced industry. To address this issue, a new approach that combines a CCT with an electrochemically accelerated corrosion test has been explored, to shorten the evaluation period. This method involves the formation of a corrosion product layer through a CCT, which leads to localized corrosion, followed by applying an electrochemically accelerated corrosion test using an agar gel electrolyte to preserve the corrosion product layer as much as possible. The results indicate that this approach can achieve comparable localized corrosion resistance, with similar localized corrosion area ratios and maximum localized corrosion depths to those obtained through a conventional CCT in half the time.

The corrosion mechanism and characteristics of steel in typical atmospheric environments directly affect the rationality of corrosion protection methods. This study investigates the corrosion evolution law of Q235 steel that has been exposed to the urban industrial atmosphere for seven years. The mass loss is used for corrosion dynamics analysis. The rust layers have been characterized by SEM, EDS, and XRD. Finally, the corrosion mechanism was analyzed through a combination of electrochemical methods, corrosion kinetics, and rust layer characteristics. The mass loss results indicate that a two-stage corrosion power function law can still effectively describe the corrosion rate of a seven-year exposure that complies with the power function law. The short-term corrosion results fail to fully reflect the corrosion performance of Q235 steel. The typical morphological structures of γ-FeOOH and α-FeOOH are identified, and the rust layers change from a loose and flat form to a granular and, finally, compact into a smooth surface. The crystalline phases of the rust layers include α-FeOOH, γ-FeOOH, Fe3O4/γ-Fe2O3 and α-Fe2O3. Corrosion products in the initial period are mainly γ-FeOOH, followed by α-FeOOH, and a small amount of Fe3O4/γ-Fe2O3. With the increase in exposure time, α-FeOOH and Fe3O4/γ-Fe2O3 in the rust layer increase. SO2 and Fe3O4/γ-Fe2O3 are the primary factors accelerating steel corrosion. During the first three years of atmospheric corrosion, the primary corrosion mechanism was governed by the acid cycle reaction mechanism. However, from the fifth year of atmospheric corrosion, oxygen-absorbing corrosion began to gradually dominate, specifically oxygen-absorbing corrosion.

In order to study the metal corrosion characteristics of Sichuan power transmission and transformation equipment in typical industrial environment, so as to provide theoretical guidance for differentiated anti-corrosion measures for transmission and transformation equipment, carbon steel was selected as the research object and aimed at Zigong, a typical salt chemical city in Sichuan Province. A one, year atmospheric corrosion test was carried out in rural environment and heavy industry polluted areas, respectively. Through macroscopic morphology observation, corrosion rate testing, scanning electron microscope (SEM), energy spectrum analysis (EDS), X-ray diffraction (XRD) and electrochemical testing, the atmospheric corrosion behavior of carbon steel in these two environments were comprehensively studied. The results show that the corrosion degree of carbon steel in Zigong area is relatively serious, and the atmospheric corrosion rate of heavy industry polluted environment is 32. 14 µm/a, even in the rural environment, it is seriously corroded, and the corrosion rate reaches 21. 92 µm/ a. The atmospheric corrosion behavior of carbon steel in the two environments is significantly different. In heavy industry polluted environment with higher chloride ion content, the surface of carbon steel is more likely to generate needle-like corrosion products, and the rust layer has poor protection and corrosion will further accelerate. In order to improve the corrosion protection effect of power transmission and transformation equipment in Zigong area, differentiated anti-corrosion measures can be adopted to appropriately increase the protection level in heavy industry polluted areas. [ABSTRACT FROM AUTHOR]

To reduce the losses caused by the atmospheric corrosion of carbon steels, it is important to establish a prediction model to determine the corrosion rate of carbon steels in natural environments. In this study, a prediction model of atmospheric corrosion of Q235 carbon steel (PMACC-Q235) in China was established by coupling the mean impact value algorithm and back propagation artificial neural network. Tempo-spatial patterns of corrosion rates in five long-exposure time categories across China were analyzed. Ten main factors affecting the atmospheric corrosion of Q235 were identified. The corrosion rates in a single year were similar (approximately 30 μm/a) and larger than those for 2 (25.30 μm/a) and 3 years (21.66 μm/a). The spatial corrosion rates in the northwestern areas were primarily lower than those in southeastern coastal areas. This could be influenced by climatic factors, such as temperature, humidity, and precipitation. All corrosion rates reached the C2 level (>1.3 μm/a), and there was some possibility that they reached higher corrosion levels. The largest probability for the C3 level in all periods was an average of 0.91, and that for the C4 level was 0.83. Spatially, higher probabilities were mainly located in the southern area, especially in Hainan, located in the south and surrounded by sea. Corrosion rates largely varied among climatic zones, and mean corrosion rates in the tropical monsoon climate zone were the largest (average of three periods 33.39 μm/a). SO2 and soluble-dust fall had the largest impact on the variations in the corrosion rates among different climatic zones. [ABSTRACT FROM AUTHOR]

The Wet Candle technique quantifies the dry deposition flux of atmospheric species onto a gauze wick. Salt deposition flux is used to rate the corrosion severity of outdoor test sites. It is important to quantify the precision of the Wet Candle method if the results are used to compare the atmospheric corrosivity of various sites. An analysis of Wet Candle precision is conducted in terms of repeatability and reproducibility. The percent deviation is 3.2% for chloride repeatability and 3.3% for chloride reproducibility. Interval testing is conducted to determine if weekly intervals added together yield a deposition flux similar to a month-long interval. Weekly results are assessed alongside meteorological data to correlate atmospheric conditions to dry deposition. Finally, the erroneous contribution of chloride from various types of gloves to deposition flux is quantified. Based on these findings, recommendations are made on how to avoid various sources of error. [ABSTRACT FROM AUTHOR]

Atmospheric corrosion is one of the major sources of hydrogen in a high-strength-steel product in service. Even low concentrations of absorbed hydrogen can cause a hydrogen embrittlement-related material degradation. The extent of atmospheric corrosion and thus the related hydrogen entry is highly dependent on the environmental parameters, such as the relative humidity. The present work focused on the hydrogen entry at low relative humidity, where atmospheric corrosion rates are expected to be low. Hydrogen insertion and distribution in CP1000 steel induced by corrosion under dried and rewetted single droplets of aqueous NaCl and MgCl2 solution were studied using the Scanning Kelvin Probe (SKP) and the resulting amounts of diffusible hydrogen were analyzed using thermal desorption mass spectrometry (TDMS). Corrosion product analyses were carried out with SEM/EDX, XRD, and Mössbauer spectroscopy. The results revealed the strong impact of salt type and concentration on the hydrogen entry into steel. The hygroscopic effect of MgCl2 and the formed corrosion products were responsible for the prolonged insertion of hydrogen into the steel even at very low levels of relative humidity. [ABSTRACT FROM AUTHOR]

The corrosion control of ductile cast irons becomes a technological challenge when supplying castings to customers due to the high reactivity of this alloy in contact with air. An interesting alternative to the protective systems such as coatings or corrosion inhibitors included in packaging processes is the chemical modification of the cast alloys by means of alloying elements addition which are able to improve the corrosion resistance of ductile cast irons. Ni, Cr and Al added to the cast alloys significantly affect their structure and properties, among them their corrosion response, when exposed to air. It has been observed that Ni and Al improve the corrosion behaviour while Cr additionally promoted pearlite and carbides formation. The results from the corrosion tests performed on ductile cast iron alloys which contain these three elements are discussed in the present work.

This work investigates the previously unexplored impact of tensile stress on oxygen reduction reaction (ORR) kinetics of a precipitation-hardened, stainless-steel fastener material, UNS S13800. ORR is known to drive localized and galvanic corrosion in aircraft assemblies and greater understanding of this reaction on structural alloys is important in forecasting component lifetime and service requirements. The mechano-electrochemical behavior of UNSS13800 was examined using amperometry to measure the reduction current response to tensile stress. Mechanical load cycles within the elastic regime demonstrated reversible electrochemical current shifts under chloride electrolyte droplets that exhibited a clear potential dependence. Strain ramping produced current peaks with a strain rate dependence, which was distinct from the chronoamperometric shifts during static tensile load conditions. Finally, mechanistic insight into the dynamic and static responses was obtained by deoxygenation, which demonstrated ORR contributions that were distinct from other reductive processes.

Air pollution, particularly in urban areas, puts human health in danger and has adverse impacts on the built environment. It can accelerate the natural corrosion rate of cultural heritages and monuments, leading to premature aging and lowering their aesthetic value. Globally, at the beginning of 2020, to tackle the spread of novel COVID-19, the lockdown was enforced in the most hard-hit countries. Therefore, this study assesses, as a first time, the plausible benefits of traffic and urban mobility reductions on the natural process of deterioration of materials during COVID-19 lockdown in twenty-four major cities on five continents. The potential risk is estimated based on exceeding the tolerable degradation limits for each material. The notable impact of COVID-19 mobility restrictions on air quality was evidenced in 2020 compared to 2019. The introduced mobility restrictions in 2020 could decrease the surface recession rate of materials. Extremely randomized trees analysis showed that PM10 was the main influencing factor for corrosion of portland, copper, cast bronze, and carbon steel with a relative importance of 0.60, 0.32, 0.90, and 0.64, respectively, while SO2 and HNO3 were mainly responsible for corrosion of sandstone and zinc with a relative importance of 0.60 and 0.40, respectively. The globally adverse governed meteorological conditions in 2020 could not positively influence the movement restrictions around the world in air quality improvements. Our findings can highlight the need for additional policies and measures for reducing ambient pollution in cities and the proximity of sensitive cultural heritage to avoid further damage. [ABSTRACT FROM AUTHOR]

Abstract—A mixed corrosion inhibitor (CI), which is an equimolar composition of sodium oleyl sarcosinate (SOS) and sodium flufenaminate (SFF), to protect the D16 aluminum alloy from atmospheric corrosion has been studied here. Polarization measurements used to assess the efficiency of preliminary passivation of the alloy with solutions of SOS, SFF, and their composition showed significant advantages of mixed CI. The features of CI adsorption on the surface of the D16 alloy are studied by XPS. It has been established that the adsorption of SOS and SFF separately results in the formation of monolayer coatings firmly bound to the alloy surface with a thickness of no more than 2.6–3.2 nm. When these CIs are adsorbed together, the layer thickness reaches 12–20 nm. This layer contains significant amounts of Al3+ ions (~20%) related to compounds with SFF and SOS, as well as aluminum hydroxides. A possible mechanism for the formation of such a protective layer is proposed. The results of corrosion tests in a humid atmosphere with daily condensation of moisture on D16 alloy samples confirm the high protective ability of the mixed CI. [ABSTRACT FROM AUTHOR]

This study reports the characteristics of atmosphere corrosivity parameters on the sea coasts of Russia, namely, on the Arctic and Pacific Oceans and the Black Sea. It gives the results of predictions of long-term corrosion losses for standard metals on the sea coasts of Russia. Experimental data on the first-year corrosion losses found in 19 representative locations on the sea coasts were used for long-term predictions. Long-term corrosion losses of metals were calculated using a power-linear function. Two variants were used to estimate the values contained in the model: the n coefficient characterising the protective properties of corrosion products, and the time of stabilisation of the corrosion process (τstab). Ranges of possible long-term corrosion losses on the sea coasts of Russia are given for the two variants of predictions. An analysis of the results thus obtained is also given. [ABSTRACT FROM AUTHOR]

A new methodology to calculate and visualize the amount of airborne sea salt with a 100m mesh resolution in high definition has been proposed in this study. A transport calculation module for airborne sea salt is implemented to the atmospheric component of the multi-scale atmosphereocean coupled model. The computational fluid dynamics model (NuWiCC-ST) results that can calculate the generation and transport of sea salt particles are incorporated to the transport calculation. The coupled methodology has been applied to create a corrosion environment map for Choshi City. The reliability of the developed method was confirmed by comparing airborne sea salt data measured using the dry gauze method with the calculated data. [ABSTRACT FROM AUTHOR]

Corrosion and stress corrosion cracking (SCC) behavior of some low-alloy high-strength steels microalloyed with Nb and Sb were in detail studied in a simulated polluted marine atmosphere. The results indicated that the high-strength steel without Nb and Sb was badly damaged by corrosion and very susceptive to SCC in a SO2-containing marine atmosphere, which was characterized by high corrosion rate and a large number of potential initiation sites for SCC cracks. By contrast, Nb addition affected little on atmospheric corrosion rate, but weakened the role of hydrogen at the boundaries of prior austenite grain and lath bainite. Sb addition significantly reduced the corrosion rate by optimizing the properties of rust layer through its synergy with Cu, and inhibited the localized anodic dissolution and acidification effect underneath. Thus, the combined addition of Nb and Sb increased the resistance to atmospheric corrosion and substantially inhibited SCC initiation.

The investigation of corrosion for carbon steel and galvanized steel has been conducted in the marine atmosphere of Eretan and Ciwaringin Districts, West Java Province. The exposure time of the field test was up to 200 days, and their corrosion rates are determined according to weight loss method. The objective of the work is to elucidate the corrosion behavior of those alloys which is affected by distances from coastline and environmental condition. The magnitude of corrosion rate for carbon steel was 20 times as high as that for galvanized steel in both districts The distance from coastline has significantly affected for the magnitude of corrosion rate, where that both alloys in Ciwaringin is lower than that in Eretan. The deposition of chloride ion in Eretan and Ciwaringin Districts were 4.305 mg/m2 day and 1.863 mg/m2 day, respectively, where the higher chloride ion can tend to increase the corrosion rates. Relative humidity (RH) which is over 60% has essential role for corrosion process as well as rainfall. The uniform corrosion attack was observed both alloys after exposure. The corrosion product phases of galvanized steel exhibits as zincite, hydrozincite and simonkolleite in Eretan as the typical coastline atmosphere phases but not in Ciwaringin. The formation of rust product for both metals lead the decrease of further corrosion attack due to the barrier between metal and environment. The usage of galvanized steel is remarkable to minimize corrosion attack compared to that of carbon steel in tropical coastline.

Weathering steels (WS) have been widely used due to the protective rust formed on the surface of the bare metal exposed to the atmosphere. They have been studied attending to specifications and characteristics in engineering, but in cultural heritage the use of this material does not follow the same criteria and has different needs which must be addressed. Among them, the design and the location of the sculpture may have an impact on the rust formed and may not be as protective as it was supposed to be. This work presents the study of the weathering steel sculpture Once Módulo which shows areas with different exposure to rainwater and different surface heterogeneities. The results obtained by Electrochemical Impedance Spectroscopy (EIS) have shown that the protective ability of the rust depends on the previous differences and that design and location of the artwork play an important role for its conservation.

The empirical modeling methods are widely used in corrosion behavior analysis. But due to the limited regression ability of conventional algorithms, modeling objects are often limited to individual factors and specific environments. This study proposed a modeling method based on machine learning to simulate the marine atmospheric corrosion behavior of low-alloy steels. The correlations between material, environmental factors and corrosion rate were evaluated, and their influences on the corrosion behavior of steels were analyzed intuitively. By using the selected dominating factors as input variables, an optimized random forest model was established with a high prediction accuracy of corrosion rate (R2 values, 0.94 and 0.73 to the training set and testing set) to different low-alloy steel samples in several typical marine atmospheric environments. The results demonstrated that machine learning was efficient in corrosion behavior analysis, which usually involves a regression analysis of multiple factors.

One of the important tasks is to deliver to the consumer a calibrated high-quality metal in a saleable condition, which requires protection from atmospheric corrosion and adverse climatic factors, protection from contamination and mechanical damage for the period of transportation to the consumer by motor transport, and storage at intermediate warehouses before going into production. A comprehensive system approach is needed to preserve the quality and appearance of the products on the way from the manufacturer to the consumer. The use of modern packaging materials, such as paper with corrosion inhibitor and polypropylene fabric reinforcement, will allow to obtain permanent guaranteed protection of the rolled surface and expands the possibilities of transportation and sales markets of metal products. The testing stage of the corrosion inhibitor included the determination of its protective properties. It is established that the advantage of packaging of rolled products in anticorrosive paper is that it, combining the functions of packaging means and means of preservation, allows you to completely abandon the expensive and time-consuming preservation of metal products with oils and greases. The use of a volatile corrosion inhibitor in the composition of the paper provides full protection of rolled products.

Bio-inspired superhydrophobic coatings have been demonstrated to be promising anticorrosion materials. However, developing robust superhydrophobic coatings through simple one-step fluorine-free procedures to meet various functional requirements remains a major challenge. In this study, we fabricated an eco-friendly superhydrophobic Al2O3@PDMS composite coating with mechanical robustness based on Al2O3 NPs, PDMS, and spray coating technique. To characterize surface morphologies, chemical compositions, surface wettability, and anticorrosion properties, FE-SEM, EDS, XPS, contact angle meter, electrochemical impendence spectroscopy, and potentiodynamic polarization techniques were employed. The electrochemical results show that |Z|0.01 Hz and Rct values of the superhydrophobic Al2O3@PDMS coating were four orders of magnitude higher than bare Q235 carbon steel, indicating a significant improvement in corrosion resistance. Furthermore, the deliquescence behaviors of NaCl salt particles and the instantaneous self-coalescence phenomenon were recorded under high atmospheric humidity to suggest that a superhydrophobic surface with Cassie–Baxter interfacial contacts can serve as an efficient barrier to suppress the formation of saline liquid thin films and protect the underlying substrate from corrosion. This robust superhydrophobic Al2O3@PDMS coating is expected to be easily applied to a variety of substrates and to find potential applications for liquid repellency, self-cleaning, corrosion resistance, and other properties.

The durability and safety of steel structures during their life cycle are affected by steel corrosion. Limited test conditions and time hinder the reproduction of actual atmospheric steel corrosion. Most test studies have focused on the effect of pitting or uniform corrosion of steel structures, leading to the development of vague engineering methods that make it difficult to design steel structures with excellent corrosion resistance. In this study, a method involving three-dimensional cellular automata and a genetic algorithm was developed for predicting the corrosion behavior of structural steel. The calculation efficiency of three-dimensional cellular automata was improved by small iterative steps and adaptive activation for potential corrosion. Furthermore, the proposed method was tested with published tests, and the results showed that the method can simulate atmospheric corrosion with excellent accuracy and efficiency. The simulation results were used to calculate the structural steel cross-sectional performance with greater accuracy than that of the method of assuming uniform corrosion. Meanwhile, with accurate material parameters, the proposed method can also simulate the atmospheric corrosion of high-performance steel of different strengths and properties.

Atmospheric corrosion of copper, exposed on a tropical island in the South-Central Pacific Ocean, was reported and compared with those of a very similar study at the same site conducted 20 years earlier. The new measurements—taken over three years of exposure, from 2010 to 2013—quantified corrosion by mass loss, characterized corrosion products by X-ray diffraction (DRX) and Raman techniques, observed the attack morphology by Scanning Electron Microscope (SEM), and evaluated the patina resistance using electrochemical techniques. The results showed a copper corrosivity category of C4, and the main copper patina compound, cuprite, was porous, nonhomogeneous, and thin. Electrochemical measurements showed cuprite layer growth as a function of the exposure time, and the morphology did not favor corrosion protection. Finally, when comparing the results to those of a study 22 years previous, the copper corrosion rates increased only slightly, even with increased contaminants associated with growing local populations and continuous tourism on the island.

Atmospheric corrosion of aluminum aircraft structures occurs due to a variety of reasons. A typical phenomenon leading to corrosion during aircraft operation is the deliquescence of salt contaminants due to changes in the ambient relative humidity (RH). Currently, the corrosion of aircraft is controlled through scheduled inspections. In contrast, the present contribution aims to continuously monitor atmospheric corrosion using the acoustic emission (AE) method, which could lead to a structural health monitoring application for aircraft. The AE method is frequently used for corrosion detection under immersion-like conditions or for corrosion where stress-induced cracking is involved. However, the applicability of the AE method to the detection of atmospheric corrosion in unloaded aluminum structures has not yet been demonstrated. To address this issue, the present investigation uses small droplets of a sodium chloride solution to induce atmospheric corrosion of uncladded aluminum alloy AA2024-T351. The operating conditions of an aircraft are simulated by controlled variations in the RH. The AE signals are measured while the corrosion site is visually observed through video recordings. A clear correlation between the formation and growth of pits, the AE and hydrogen bubble activity, and the RH is found. Thus, the findings demonstrate the applicability of the AE method to the monitoring of the atmospheric corrosion of aluminum aircraft structures using current measurement equipment. Numerous potential effects that can affect the measurable AE signals are discussed. Among these, bubble activity is considered to cause the most emissions.

The influence that the composition of coatings based on a cycloaliphatic epoxy resin exerts on their physicomechanical and electrochemical properties was studied with the aim of improving the protective effect of the coatings. Three coating formulations were chosen as investigation objects: without fillers (formulation I), with highly dispersed fillers (muscovite and titanium dioxide, formulation II), and with the same fillers and an organic modifier (epoxy rubber, formulation III). The hardness, adhesion (cross-cut test), contact angle, impact and bending strength, and heat resistance of the materials obtained were determined. Electrochemical trials of the coatings were performed using potentiodynamic polarization. Based on the results of the studies, formulation III containing highly dispersed fillers and epoxy rubber was chosen for further field trials under the conditions of humid tropical climate. [ABSTRACT FROM AUTHOR]

• Long term corrosion of a high-tin bronze bell in a steeple under marine atmosphere. • A corroded high-tin α/δ alloy Cu-Sn-Pb: comparaison with ancient buried artefacts. • Complex alteration due to environment, shocks and vibrations of bells. • Particular pitting corrosion of α/δ alloy. • Hypothesis of a micro-infiltrating alteration scenario of the α/δ bronze bell. α/δ bronze bells are heritage materials subject to corrosion. The alteration of a high-tin bronze bell casted in the 1930s and exposed to a marine environment in a steeple was studied. The ternary bronze (Cu-Sn-Pb) alloy displays inclusions and a porosity due to micro-shrinkages and poor gas evacuation. This altered bronze is characterized to (1) assess the influence of the manufacturing techniques and (2) hypothesize a micro-infiltration scenario of its alteration. After exposure to the atmosphere, a transformed superficial medium overlaying layers of atacamite-paratacamite-cassiterite appears. Under them, the corrosion of the α dendritic structure and α/δ eutectoid characteristic of bronze bell is evidenced. The α pitting has a pronounced multilayered structure of cassiterite and cuprite-copper chloride, whereas the δ corrosion is composed of cassiterite and traces of cuprite. To understand better the lead impact on corrosion process, samples of the alloy were exposed in the laboratory to a synthetic marine solution. The long-term corrosion behavior of the studied bell shows some similarities to those of other high tin bronze artefacts. The hypothesis of a corrosion scenario emphasizes the importance of the bells manufacturing techniques, α/δ structure of the ternary Cu-Sn-Pb alloy, and infiltrating networks of environmental fluids. [Display omitted] [ABSTRACT FROM AUTHOR]

The corrosion behavior of carbon steel coated with a zinc‐rich paint containing two metallic compounds, Al2(SO4)3 and CaO, as anticorrosive additives was examined under wet and dry cyclic corrosion test conditions. The zinc‐rich paint coating without the two metallic compounds formed a white corrosion product and red iron rust on the surface after the corrosion test, whereas the coating with the metallic compounds showed reduced surface corrosion products. The corrosion current density of the painted steel substrate decreased drastically due to the incorporation of metallic compounds in the paint. The zinc‐rich paint coating modified with the metallic compounds contained dispersed simonkolleite (Zn5(OH)8Cl2·H2O) phase and possibly very fine CaSO4 particles, which remarkably improved the protectiveness of the zinc‐rich paint coating. [ABSTRACT FROM AUTHOR]

As a part of Corrosion Map of Sichuan project, atmospheric corrosion behavior of carbon steel was investigated in the subtropical atmospheric environment by weight loss method at five exposure stations. Results indicated that an annual corrosion rate of carbon steel was between 0.66 and 23.6 μm/y. The morphology and composition of corrosion products formed on the exposed steels were identified by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS) and Raman spectroscopy. Subtropical atmospheric corrosion rate of the steel increases in high-rainfall and temperature environment. Bigger and deeper pits are preferred to form in a humid atmosphere. The corrosion products exhibited an uneven distribution and consisted mainly of goethite (α-FeOOH), lepidocrocite (γ-FeOOH), magnetite (Fe3O4) and hematite (Fe2O3). The electrochemical corrosion of carbon steel in solution is an activation-controlled process, and a stable passive region was not observed for the steel. Electrochemical measurements showed that deposits on carbon steel decreased the corrosion resistance. [ABSTRACT FROM AUTHOR]

This study evaluates environmental aggressiveness and atmospheric galvanic corrosivity categories in Chile (Classification of Industrial and Marine ATmospheres test) by installing bolts in electrical transmission towers in the Valparaiso region across four exposure sites: Playa Ancha, San Sebastián, Las Vegas, and San Felipe. Classifications of marine corrosion index (MCI), industrial corrosion index (ICI), and atmospheric corrosion index (ACI) used different galvanic couples: aluminum/steel for MCI, aluminum/copper for ICI, and aluminum/polyethylene for ACI. Corrosion indices varied by season (summer, autumn, winter, and spring), for which couples were exchanged every 3 months. Intraseason variation depended mainly on the meteorochemical variables of the zone, the Cl−/SO2 ratio, and the presence of general and pitting corrosion in the aluminum. The results indicate that, regardless of environmental condition, the aluminum in Al/steel (MCI) and Al/copper (ICI) couples presented a higher corrosion rate than when not forming a galvanic couple (ACI). Moreover, under higher environmental chloride, these differences increase. The Playa Ancha station presented the highest ACI. [ABSTRACT FROM AUTHOR]

To simulate the atmospheric corrosion of Mo-alloying steels in salinity environment, artificial β-FeOOH rust particles were synthesized by aerial oxidation of a mixture of aqueous FeCl2 and MoCl5 solutions at different Mo/Fe molar ratios. Increasing Mo/Fe ratio suppressed the β-FeOOH formation to generate amorphous materials. Added Mo5+ was easily incorporated in the products and remarkably inhibited the crystallization and particle growth of β-FeOOH. Specific surface area of the Mo5+-doped β-FeOOH steeply decreased with an increment of Mo/Fe ratio, meaning the strong aggregation of β-FeOOH particles by adding Mo5+. It is likely, therefore, that atmospheric corrosion of Moalloying steels in salinity environment forms the dense, compact and stable rust layer consisting of fine β-FeOOH rust particles on the steel to prevent further corrosion of the steel. [ABSTRACT FROM AUTHOR]

The investigation of atmospheric corrosion of mild carbon steel as representative of offshore infrastructure has been carried out in the marine tropical of Pelabuhan Ratu, West Java, Indonesia. They are exposed up to 76 days of periods, and their corrosion rates are determined according to ASTM G1-03. The surface morphology, the elemental compositions and compounds were observed using a scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The environmental parameters of the test site are monitored during exposure, such as air temperature, relative humidity (RH), airborne salinity and dew temperature. Based on the results, the corrosion rates of steels were 2.79 and 2.8 mpy within the 27 and 76 days exposures, respectively. The presence of chloride deposition on the surface of steel can increase the severity of corrosion. Moreover, the detrimental effect of chloride was observed in rust product, which was covered by an oxygen element. The main phases of rust products present were magnetite (Fe3O4) and hematite (á-Fe2O3.H2O). Several cracks were observed in the rust layer, which tended to exfoliate and lose adherence and protectiveness from further corrosion attack. [ABSTRACT FROM AUTHOR]

The mild carbon steel (CS) A-36 and weathering steel A-588 were exposed to the outdoor atmosphere at two different locations in tropical Panama. After a 10-year exposure, the results indicate that the chloride deposition rate and the type of steel play an important role in the corrosion behaviour of tested steels. Both types of steel mainly contain lepidocrocite and goethite as corrosion products at the urban site, while the corrosion products of steels exposed to a moderate marine atmosphere consisted of lepidocrocite, goethite and maghemite. The large fractions of maghemite in the corrosion products of steel A-36 suggest that this phase is interrelated to the higher corrosion rate of CS in the moderate atmospheric environment. [ABSTRACT FROM AUTHOR]

Carbon steel AISI 1020 was exposed to environmental conditions along a transect of the Atacama Desert to gather experimental evidence to identify the local atmospheric mechanism that triggers corrosion through a buildup of water layer formation on the metal surface in addition to corrosion evolution. Coupons initially left in selected sites were periodically collected to determine weight loss and surface attributes by scanning electron microscopy and X-ray diffraction. In addition, meteorological conditions were measured in addition to a fog water collector in one site. During the study period, the predominant conditions were the absence of rain, clear skies, and large daily oscillations in temperature and relative humidity. The evidence indicates a water film formation on a metal surface either from a vertical water flux as fog water droplets and/or by the dew water harvesting mechanism. The uptakes of oxygen and chlorides during the corrosion process were highest in the coastal site P0 and gradually decreased with the increasing distance from the coast. This is attributed to both humidity and saline marine fog intrusion from the coast. The oxide layer evolved to form a compact layer with main constituents of lepidocrocite, goethite, and lesser amounts of akageneite. The corrosion depth can be modelled by a simple power function d=AtB with B < 1, indicating a deceleration process.

The seismic performance of four different kinds of steel plate shear walls (SPSWs) before and after corrosion are investigated in this paper, including flat steel plate shear walls (FSPSWs), SPSWs with vertical slots in the middle (VSSPSWs), SPSWs with orthogonal stiffeners (OSPSWs) and SPSWs with silts on both sides (BSPSWs). A numerical model that can be validated by existing quasi-static cyclic tests is developed by ABAQUS 6.13. The seismic performance of SPSWs under cyclic loading and atmospheric corrosion is investigated. The results show that (1) compared with FSPSWs, the ultimate shearing strength, initial stiffness, energy dissipation, and ductility of OSPSWs are significantly improved under cyclic loads when both VSSPSWs and BSPSWs are reduced in ultimate shearing strength and energy dissipation. (2) The performance of the FSPSW is most affected by atmospheric corrosion but setting stiffeners can significantly improve the hysteretic performance after corrosion. Meanwhile, the effect of the VSSPSW is better than that of the BSPSW in decreasing the ultimate shearing strength, although both decrease more tardily than that of the FSPSW. (3) The relationships between the ultimate shearing strength and corrosion time of SPSWs are fitted into four equations in this paper, which can be used in practical situations.

Based on peridynamics, an atmospheric stress corrosion model was proposed. In this model, the role of hydrogen and stress in anodic-dissolution-dominated stress corrosion cracking was considered, and atmospheric corrosion was characterized by the change in liquid film thickness on the metal surface in the atmospheric environment. The near-field kinetic anodic dissolution model and the atmospheric corrosion model were coupled by varying the liquid film thickness. The thickness of the liquid film depended on factors such as the temperature, relative humidity, and hygroscopic salts. We validated the model using stress corrosion behavior from the literature for 304 stainless steel in a simulated atmospheric environment. The results of the model captured the crack expansion process. The obtained crack expansion direction and branching behavior agreed well with the experimental results in the literature.

Chamberprotection of metals from atmospheric corrosion is a variety of vapor-phase inhibition. It is based on the effect of adsorption films formed in the vapors of low-volatile corrosion inhibitors at elevated temperatures. The paper analyzes the specific features of the chamber protection of a magnesium alloy with chlorobenzotriazole. It has been found that the protective properties of surface films formed in hot vapors of this compound increase upon exposure of the metal to air. The processes of structuring of protective films that occur in this case have been studied by a set of corrosion, electrochemical and physical methods. It has been shown that chamber treatment of the alloy is accompanied by chlorobenzotriazole adsorption and uniform thickening of the surface oxide-hydroxide layer. In this case, the corrosion processes slow down by a factor of up to 10. Prolonged exposure of the samples in air after the chamber treatment results in additional oxidation of magnesium and hydroxylation of the oxide. However, the oxide-hydroxide layer does not grow on the entire surface, but as separate islets. Such a change in the structure of the surface films results in an additional 10-fold increase in the corrosion resistance of the magnesium alloy.