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• Protectiveness of fluoropolymer coating (FA-MS) on patinated bronze was assessed. • FA-MS coating covered the patinated bronze with a transparent layer few μm thick. • Good durability of FA-MS on bronze artwork was observed in real outdoor exposure. • Brushing was an efficient method for removing FA-MS without altering bronze patina. The application of protective coatings for the conservation of outdoor metallic artworks is currently considered the best approach actively employed. This paper focuses on the evaluation of the protectiveness of an optimised fluorosilane (FA-MS) coating with low occupational hazard impact and high inhibition efficiency. FA-MS coating was applied on a typical historical as-cast bronze (Cu-Sn-Zn-Pb), artificially patinated by synthetic acid rain dropping, to simulate natural unsheltered patinas. Subsequently, the patinated bronze was coated by brushing and then artificially aged by synthetic rain dropping. In order to investigate the coating-patina system, a multi-analytical approach was applied including scanning electron microscopy coupled with elemental analysis (FEG-SEM with EDS), microstructural analysis of cross-sections produced by Focused Ion Beam milling (FIB) and X-ray Photoelectron Spectroscopy (XPS). The coating homogenously covered the whole patinated surface producing a transparent layer few μms thick. The weathering solutions were also analysed for the assessment of metallic cations release. FA-MS showed excellent protective performances for the patinated bronze exposed to simulated outdoor conditions. Very high values of inhibiting efficiency in terms of metal release in the weathering solutions (up to 99%) were measured. In order to investigate all the necessary requirements for application in conservation field, the durability of FA-MS was also tested on a real bronze artistic casting, in terms of limiting the alloy composition changes (measured by in situ XRF) over time. A good durability of the coating was observed during the ongoing field exposure test. Lastly, reversibility of FA-MS was investigated by applying different mechanical cleaning methods, such as brushing and blasting. The reversibility was assessed by the evaluation of the morphology (colour change, surface roughness and optical microscopy) and the composition (SEM-EDS and Py-GC-MS chromatography) of the cleaned surfaces. Cleaning by brushing proved to be an efficient method for removing this coating without significantly altering the bronze patina. [ABSTRACT FROM AUTHOR]

Q235 and Q345 carbon steels were exposed for up to 24 months at three test sites of tropical and subtropical climate. The atmospheric corrosion kinetics of Q235 and Q345 was studied by weight‐loss measurement. The results show that the ranking of the atmospheric corrosivity from weak to strong of the three test sites is Xishuangbanna, Guangzhou, and Wanning. The kinetics of the atmospheric corrosion process presents two stages with an accelerated second stage in marine environments of high chloride ion content and high relative humidity, whereas no second stage appears in the kinetics curves in rural and industrial urban environments. The corrosion acceleration stage in the marine environment of the Wanning site is attributed mainly to the high chloride ion concentration and loose rust layer structure. [ABSTRACT FROM AUTHOR]

Atmospheric corrosion is a natural surface deterioration process of the ferrous metal (steel) owing to electrochemical process with the variation of highly sensitive atmospheric parameters surrounding the metal. A global empirical model developed for estimating short-and long-term atmospheric corrosion rates by establishing empirical coefficients statistically (with R2 = 0.99) having 95% confidence limit. It predicts atmospheric corrosion, based on the corrosion formation mechanisms and the combined impact of the environmental parameters and further abates the location and time limitations. Corrosion studies are performed for 39 years of atmospheric data collected in the study area. Environmental parameters changes in the study area over the four decades (1979–2018) are observed and corrosion map for each decade in total 39 years data based corrosion map prepared using the developed empirical equation. The developed empirical equation closely predicts atmospheric corrosion for the experimental datasets collected at 88 different continental locations while the ISO exhibits uncertainty. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology 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.)

The atmospheric corrosion of metallic materials causes great economic loss every year worldwide. Thus, it is meaningful to predict the corrosion loss in different field environments. Generally, the corrosion prediction method includes three parts of work: the modelling of the corrosive environment, the calibration of the corrosion effects, and the establishment of the corrosion kinetics. This paper gives an overview of the existing methods as well as promising tools and technologies which can be used in corrosion prediction. The basic corrosion kinetic model is the power function model and it is accurate for short-term corrosion process. As for the long-term corrosion process, the general linear models are more appropriate as they consider the protective effect of the corrosion products. Most corrosion effect models correlate the environmental variables, which are characterized by the annual average value in most cases, with corrosion parameters by linear equations which is known as the dose-response function. Apart from these conventional methods, some mathematical and numerical methods are also appropriate for corrosion prediction. The corrosive environment can be described by statistical distributions, time-varying functions and even geographic information system (GIS), while the corrosion effect can be captured via response surface models and statistical learning methods. [ABSTRACT FROM AUTHOR]

This article introduces differential evolution fitting-based optical step-phase thermography for fast, contactless, and high-accurate measurement of micrometer thickness, which is widely needed in industrial applications. In this process, frequency-domain characteristics of thermal wave propagation are extracted to estimate micrometer thickness. The quantitative relationships between the frequency-domain thermal characteristics and different thicknesses of micrometer structures are precisely discussed. The effect of sampling frequency is emphasized for measuring micrometer thickness and improving the sensitivity of the frequency-domain features as measurement tools of thickness. In particular, differential evolution is introduced to implement adaptive global optimization of transient thermal responses fitting and to eliminate the frequency aliasing in micrometer thickness measurement when the sampling frequency is not satisfactory. Finally, experimental studies have been conducted to compare the effectiveness of principle component analysis, independent component analysis, and the proposed method for quantitative evaluation of atmospheric corrosion. It can be seen that the frequency-domain features imaging is capable of quantitatively characterizing micrometer thickness in a visualized way, and the influences of abnormal surface states and nonuniform heating are completely eliminated. [ABSTRACT FROM AUTHOR]

Atmospheric corrosion of carbon steel AISI-1018 was studied in a coastal zone of tropical climate of Cuba with the presence of technologies aimed at the oil extraction and refining in operation. Two outdoor exposure sites were placed in the study zone. Wooden racks with device for determination of aggressiveness agent's monthly and averages annual, a sensor for the measurement of relative humidity-temperature complex, as well as fifteen specimens of carbon steel AISI-1018 for determination of corrosion rate monthly and annual, were installed in each exposure site placed at distance from the sea of 70 and 50 m without shielding effect. Corrosivity category of the atmosphere estimated from the typical characterization of the atmospheric environment and from the indirect values of corrosion ratewas similarity to determine from the annual values of corrosion rate determined directly for carbon steel at the two exposure sites in the study zone. Corrosivity categories of the atmosphere determined was high (C4). The atmospheric corrosion of carbon steel is influenced not only by the wet deposition of sulfate ions, but also by the wet deposition of chloride ions at both exposure sites. The relative humidity-temperature complex had a higher influence on the atmospheric corrosion of carbon steel at the exposure site placed at a higher altitude on sea level in the study area. The effect of height on sea level also influenced in a different classification of the types of atmosphere between the two exposure sites. [ABSTRACT FROM AUTHOR]

Biomarkers are complex molecules derived from formerly living organisms such as bacteria, fungi, algae, plankton, lichens, mosses, ferns and other higher plants. Biomarker concentrations are relatively low in oil and due to the high stability of its chemical structures, they are archaeological witnesses to its formation and transformation process. Based on the qualitative and quantitative composition of the molecules, it is possible to know the degree of oil biodegradation, determination of depositional environmental conditions (such as marine, terrestrial, deltaic, or hypersaline environments) and the type of precursor organic matter in the source rock. In addition, it is possible to carry out environmental, forensic and behavioral studies of hydrocarbon reservoirs. The objective of the present work is to develop an analytical methodology to obtain the distribution of saturated terpanes and steranes biomarkers using combined gas chromatography-mass spectrometry. From the extracted ion chromatograms, the peaks of 37 compounds from the group of terpanes and 19 compounds from that of the steranes were identified and integrated. The distribution was determined with their characteristic fragment ions of m/z 191, m/z 217 and m/z 218. Repeatability, intermediate precision and relative standard deviations were lower than 5%, which shows that the results are in agreement with the quality criteria established for analogous chromatographic methods. [ABSTRACT FROM AUTHOR]

Atmospheric corrosion of carbon steel was studied in the oil refinery of Havana, Cuba. Four exposure sites, three in outdoor exposure condition and one in indoor exposure condition were placed in the refinery during one year of study. Corrosivity categories of the atmosphere higher, C5 very high and CX extreme, were expected for atmosphere classified as industrialcoastal, industrial and industrial highly polluted, due to high deposition of sulfate ions. Equivalence between two ways of estimation of corrosivity categories of the atmosphere was demonstrated for the atmospheres classified in the outdoor exposure condition. The high deposition of sulfate ions higher than chlorides, bring as results difference between the category of estimation and determination for atmosphere classified as industrial and industrial highly polluted. The category high (C4) was estimated and medium (C3) was determined. However, for an atmosphere classified as industrial-coastal, where the deposition of chloride ions is higher without being higher than sulphate ions, there was equivalence between the two ways of estimation and determination high (C4) of aggressivity corrosion for outdoor exposure condition. The chloride deposition salts remain as the most influential factor in the atmospheric corrosion of carbon steel, demonstrated in this study, for an atmosphere classified as industrial highly polluted. For the indoor exposure condition, there was equivalence between the estimation and determination of aggressivity corrosion of the atmosphere high (IC4) in the refinery. The increase in RH is the most influential factor in the atmospheric corrosion of carbon steel. [ABSTRACT FROM AUTHOR]

There are many potential causes of corrosion in animal buildings. Animals exhale large quantities of moisture into the air creating high relative humidity in the building if the moisture is not properly vented. High humidity increases the potential for condensation. In addition, ammonia may be found in large quantities in animal buildings. Ammonia is released from manure and urine. In addition, ammonium chloride is used as a nitrogen source in fertilisers. In this study, the atmospheric corrosion of hot‐dip‐galvanised steel and zinc alloy‐coated steel such as zinc–aluminium and zinc–aluminium–magnesium has been studied in atmospheres containing different levels of ammonia. Investigations have also been conducted at different levels of ammonium chloride. The results are discussed in view of the mechanisms of corrosion of zinc and zinc alloy‐coated steel in ammonia and ammonium chloride‐containing environments. [ABSTRACT FROM AUTHOR]

Iron objects are among the most abundant type of metal artefacts in the archaeological record and help to deepen our understanding of past societies and their technologies. However, sampling of them is often problematic due to the destructive character of most analytical methods. In this study, iron and oxygen isotope compositions of iron artefacts from marine and water under-saturated oxidising environments were analysed in a first attempt to gather artefact information from the corrosion layer without sampling the object directly. No Fe isotope fractionation between artefact and its corrosion products was recognised for both environments but cannot be excluded for marine environments. Hence, the artefact’s Fe isotope composition can be determined from the corrosion layer. This allows the characterisation of artefacts which cannot be sampled directly. Because the available data precluded a clear identification of the underlying processes, possible fractionation mechanisms resulting in this situation are presented. Furthermore, the results of this study indicate that corrosion products have the same oxygen isotope composition as their source water. As for marine corrosion, general absence of oxygen isotope fractionation could not be manifested here, because only a small sample size was available for the present study. However, a complex interplay of many parameters governs the oxygen isotope compositions of corrosion products on metallic iron. Especially oxidising environments above the water table have a strong impact on the oxygen isotope composition of the corrosion layer. The first-order controlling mechanisms, such as evaporation, are set by the local environment and cannot be reconstructed. Therefore, the oxygen isotope composition of corrosion products seems to bear no valuable potential for archaeometallurgical research. [ABSTRACT FROM AUTHOR]

This study focuses on atmospheric corrosion of carbon steel and weathering steel exposed at two different locations with dissimilar meteorological parameters and airborne pollutants in Thailand. The samples are subjected to an outdoor atmosphere for up to 36 months at Rayong, close to the Gulf of Thailand, and Phangnga, near the Andaman Sea. Thickness loss (µm), corrosion rate (µm/year) together with corrosion product morphology and composition are systematically analyzed using X‐ray diffraction and a scanning electron microscope. Corrosion resistance of the tested steels exposed at both locations is discussed based on the above‐mentioned parameters and calculated corrosion kinetics. The results indicate that the total time of wetness, amount of rainfall and chloride deposition rate play an important role in corrosion behavior of the tested steels. Alloying elements, copper, chromium and nickel, are shown to improve corrosion resistance of the samples when exposed at the location with a higher chloride concentration. [ABSTRACT FROM AUTHOR]

Stainless steel (SS) is one of the most widely used engineering materials in marine engineering. However, its corrosion in the marine atmospheric environment due to the high concentration of Cl− is a problem. The SS corrosion is a threat to the development and security of marine industry; therefore, evaluating the corrosion resistance of SSs is necessary. In this work, atmospheric corrosion detection probes based on a symmetrical electrode system were used to study the corrosion behaviors of 304 SS and 2205 duplex stainless steel (DSS) in a simulated marine atmosphere. A theoretical model for electrochemical noise (EN) data analysis based on the Thevenin electrochemical equivalent circuit (EEC) model was established. The relationship between the EN characteristic parameters and the corrosion rate was obtained. The Thevenin EEC model analysis showed that the relationship between the noise resistance (Rn), the noise impedance [Rsn(f)], and the impedance modulus (|Z(f)|) was R n ≈ R sn = 3 Z (f) . Thus, Rn and Rsn can be used as indicators for quantitative corrosion evaluation. The results of EN detection for the 304 SS and 2205 DSS showed that in a simulated marine atmospheric environment, the passive films on the two SSs were relatively intact at the initial exposure stage, and their dissolution rates were slow. The corrosion resistance of the 2205 DSS was higher than that of the 304 SS. With the deposition of Cl− on the SS surface, pitting was initiated and the dissolution rate increased. The pitting initiation process on the SS surface was random, and part of the active pores could be repassivated. [ABSTRACT FROM AUTHOR]

The cleaning of metallic artworks is a crucial step for their preservation. Cleaning operations generally aim at removing deposits and corrosion layers, and all the non-stable and potentially reactive phases formed as a consequence of the interaction of the metal with the environment. Thus, all secondary-formed compounds and layers that can undermine the overall preservation of the artwork, both from the esthetic and the corrosion point of view, should be removed. On the other hand, superficial stable patinas contributing to the artistic and historic value of the objects and that may provide protection to the metallic surface should be preserved. The optimal cleaning procedure should be able to promote a long-term improvement of the corrosion resistance of the surfaces. Therefore, the long-term monitoring of the corrosion behavior of the cleaned surfaces with electrochemical techniques could provide valuable information for the selection of the optimal methodology. In this work, five cleaning procedures have been applied to five bronze sculptures. The cleaned surfaces have been characterized following a multi-analytical and non-invasive approach, and the long-term evolution of their corrosion behavior has been monitored by means of on-site non-invasive linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) measurements for more than 2 years. [ABSTRACT FROM AUTHOR]

Coloured enamels from the materials used in Modernist workshops from Barcelona were produced and compared to those found in the buildings to explore the reason for the reduced stability of the blue and green enamels. They were made of a lead-zinc borosilicate glass with a low softening point, reasonable stability to corrosion and matching thermal expansion coefficient with the blown base glass, mixed with colourants and pigment particles. The historical enamels show a lead, boron and zinc depleted silica rich amorphous glass, with precipitated lead and calcium sulphates or carbonates, characteristic of extensive atmospheric corrosion. The blue and green enamels show a heterogeneous layered microstructure more prone to degradation which is augmented by a greater heating and thermal stress affectation produced by the enhanced Infrared absorbance of blue tetrahedral cobalt colour centres and copper ions dissolved in the glass and, in particular, of the cobalt spinel particles. [ABSTRACT FROM AUTHOR]

Electronic components are often susceptible to deterioration by environmental effects. Several studies have been reported on atmospheric corrosion of electronic devices with focus on functionality, storage capacity, and their miniaturization. However, there is a lack of studies focused on identifying the components most susceptible to atmospheric corrosion, the corrosion products generated in them, and the possible variables that have a greater impact on deterioration. The present study is focused on linking the deterioration of electronic boards with temperature and humidity cycles. This was accomplished through accelerated tests inside an atmospheric chamber, where the concentrations of pollutant gases (NO2 and SO2) are kept constant. Each trapezoidal cycle within the accelerated tests equals one day of field exposure. The results show that the NO2 and SO2 gasses reduced the life of the electronic components by 49.8%. The SO2 gas was found to be the contaminant gas that most influenced the deterioration of electronic devices. Energy-dispersive spectroscopy (EDS) show the formation of CuSO4. The development of protective coating against these pollutant gasses could improve the operation of electronic components. [ABSTRACT FROM AUTHOR]

The effect of Sb on the corrosion resistance of low-alloy steels in a simulated polluted marine atmosphere was studied by electrochemical testing and weight loss measurements. The results showed that the addition of Sb could improve the corrosion resistance, which was confirmed by the increased polarization resistance of the steels that contained Sb. X-ray photoelectron spectroscopy analysis of the surfaces indicated that Sb participated in the formation of corrosion products and formed Sb2O5 in the rust layers. In addition, the precipitation of Sb2O5 with iron oxyhydroxides made the rust layers more uniform and compact, which provided the Sb-containing steels with better corrosion resistance than the Sb-free Steel. [ABSTRACT FROM AUTHOR]

The flagship congress of the European Federation of Corrosion (EFC), EUROCORR 2019, was held under the theme of 'New Times, New Materials, New Corrosion Challenges' at the Barcelo Sevilla Renacimiento, Seville, Spain, from the 9th to 13th September. This major corrosion event will be reviewed in four parts over four issues, with the present instalment summarising the opening sessions, plenary lectures and technical sessions on corrosion in oil and gas production, the refinery and petrochemistry industry, archaeological and historical artefacts and atmospheric corrosion. [ABSTRACT FROM AUTHOR]

The corrosion behavior of steel exposed to a simulated marine atmosphere at different temperatures (from 30 to 60 °C) has been investigated. The corroded specimens were analyzed gravimetrically and by scanning electron microscopy, x-ray diffraction and electrochemical techniques. The results revealed that the morphology of volcanic bulge can be observed on the sample surface at 60 °C, which can be attributed to the effect of temperature on the diffusion rate of ions. As the exposure temperature is increased, the relative content of the main corrosion products changed greatly. The increase in temperature not only promoted the transport of aggressive ions Cl− and the formation of local corrosion, but also affected the solubility of oxygen gas in the thin film, leading to the increase in the relative content of Fe3O4 and the acceleration of corrosion. [ABSTRACT FROM AUTHOR]

The atmospheric corrosion behavior of Zn was studied in laboratory environments containing constituents that have not previously received much attention, in particular, humidity, SO2, NH 3, and O 3, along with ultraviolet (UV) light irradiation and a preloading of NaCl. After exposure, corrosion rates were measured using mass loss, and corrosion products were identified by X‐ray diffraction, Fourier transform‐infrared spectroscopy, and energy dispersive spectroscopy. In this study, UV light and O 3 did not significantly affect the Zn corrosion rate in the absence of Cl −. However, when NaCl was present, UV light inhibited the Zn corrosion rate below 90% relative humidity (RH) and accelerated the Zn corrosion rate at 99% RH. The presence of UV light also increased the formation of zinc hydroxyl sulfate and gordaite when exposed to 120 parts per billion (ppb) SO 2 and NaCl. The combination of SO 2 and O 3 with the preloading of NaCl increased the corrosion rate of Zn compared with NaCl alone. NH 3 at a concentration of 550 ppb did not have a significant effect on the Zn corrosion rate. [ABSTRACT FROM AUTHOR]

Zn coated steel (Z) and ZnAlMg coated steel (ZM3.7/3 = Zn–Al (3.7 wt.%)‐Mg (3.0 wt.%)) have been exposed for 6 years at twelve different weathering sites world wide. The mass loss of the coatings have been measured after 1, 2, 4, and 6 years exposure. From the results, it is shown that ZM3.7/3 had always a better corrosion performance compared to Z. The ratio of performance after 6 years of exposure varied from about 1.4 to 4.4 with a mean value of 2.8. At temperate marine sites (e.g., temperature between 9–20°C) with low to moderate SO 2 pollution a good relationship was observed between the relative performance of ZM3.7/3 and the corrosion rate of Z. It was thus concluded that ZM3.7/3 has a better relative performance in harsh environments. The corrosion performance of ZM3.7/3 was shown to be connected to the formation of protective corrosion products. [ABSTRACT FROM AUTHOR]

The atmospheric corrosion resistance of metals can be reached by the formation of ultrathin protective films on their surface. Over recent years, a fundamentally new feasibility of the nanodimension films on metals capable of ensuring high atmospheric corrosion resistance of metals at least for the period of transportation and in-process storage of the metals was studied. The method of formation of such films by semivolatile nontoxic compounds capable of being adsorbed on metal surface from gas phase at increased temperature (chamber inhibitors) was proposed for this purpose. It is based on the use of such low-volatile organic inhibitors, which are prone to chemisorption on protected metal, and, as a consequence, can provide the stability of the adsorbed layers and long protection after-effect. It was shown by the complex of accelerated corrosion, electrochemical, and optical techniques that the treatment of zinc by vapors of low-volatile corrosion inhibitors at increased temperature and suitable compilation of the reagents results in the formation of the adsorption film with the effect of the long protection after-effect. [ABSTRACT FROM AUTHOR]

The influence of storage locations of two grades of rutile flux cored welding wires on their surface condition and the strength of the welds made with them were studied. Wires were stored in real urban conditions (Gdańsk and Katowice) for 1 month, simultaneously recording changes in conditions: temperature and relative humidity of the environment. Visual tests of wires in the delivered and stored condition as well as visual and tensile strength tests of welds made with them were carried out. It was found that the surface of the wires underwent more intense degradation (atmospheric corrosion) during storage in Katowice than in Gdańsk. Significant difference in tensile strength was observed only for padding welds made using Gdańsk stored wires. The lowest recorded tensile strength value was not lower than the standard requirements for the wires. [ABSTRACT FROM AUTHOR]

A finite element method (FEM) model was used to determine the potential, current, and current density distributions for a multi-material fastener/hole-in-plate configuration in an atmospheric environment. The plate consisted of bare Pyrowear 675 with or without a ZnNi coating, and the fastener consisted of Ti-6Al-4V with or without an anodization surface treatment. The potential distribution within the fastener hole was the focus of this work, as this region would represent the location of highest stress within the fastener/panel geometry. Separately, existing literature data were augmented by fracture mechanics-based evaluations of the environment-assisted cracking behavior of Pyrowear 675 as a function of electrode potential Pyrowear 675 in 3.0 M NaCl. Combining the fracture mechanics and FEM results allowed for a unified framework which was able to narrow a material selection matrix of 13 total scenarios to three scenarios, in an atmospheric environment of 0.6 M NaCl, specifically. The delayed drying out of occluded regions after the surface electrolyte has been evaporated was accounted for, with only one of the studied material selection combinations able to reduce the crack susceptibility under those conditions. A single pit within the fastener hole was also considered, and it was determined that the size of the pit had a larger impact on the potential than the location of the pit, which will aid in future computational assumptions. • A coupled methodology for material design and coating degradation was expanded to atmospheric conditions. • Selective plating and material selection enabled mitigation of environmentally assisted cracking in two environments. • The possible pitfalls of over- or under-polarization through galvanic couples is discussed. • In the presence of a pit inside of the fastener hole, the galvanic potential is dominated by pit size rather than location. [ABSTRACT FROM AUTHOR]

The corrosion interaction mechanism of carbon steel was studied to address the mutual interference of carbon steels under coating defects in the atmospheric environment. The findings revealed that the electrochemical interactions between the carbon steels were primarily influenced by the solution resistance, cathode area, and cathode-to-anode area ratio. In addition, the upper limit of the accelerating effect of the macrocell current on the anodic corrosion rate was determined by theoretical deduction. Finally, the corrosion-accelerating effect of the macrocell current was determined to assess the corrosion rate of carbon steels with electrochemical interactions under defects. • The variation of macrocell current with electrolyte film thickness was monitored. • i corr of carbon steel was obtained by fitting the potentiodynamic polarization curve. • Solution resistance and area ratio on macrocell current were theoretically analysed. • The mechanism of macrocell current on carbon steel corrosion in the atmosphere was studied. [ABSTRACT FROM AUTHOR]

Corrosion of aluminium alloy 6063-T6 with exposure to simulated steel corrosion products using ferric chloride droplets was investigated. Focus of these experiments was to understand the role of oxygen in the redox process; therefore, samples were exposed to standard atmospheric conditions as well as to oxygen-derived conditions. Respirometric measurements indicate that the hydrogen evolution reaction (HER) is the dominant cathodic reaction. Especially in the initial stages when the corrosion rates are the highest, the HER occurs almost exclusively. At the later stages the oxygen reduction reaction (ORR) barely takes over as the main cathodic reaction. The dissolved volumes and maximum corrosion depths determined with X-ray Computed Tomography (XCT) were more significant for those samples deprived of oxygen. The composition of iron-rich deposits formed consisted of magnetite and maghemite, supporting exposure conditions where reactions were deprived of oxygen. • Respirometric measurements highlight the critical role of the hydrogen evolution reaction (HER) in the studied process. • The HER emerges as the primary cathodic reaction during the initial exposure stages, leading to the highest corrosion rates. • Utilising XCT and Respirometric measurements; researchers uncover valuable insights into the role of O 2 in the redox process. • O 2 deprived conditions exhibit amplified dissolved volumes and corrosion depths, indicating the HER's dominance. [ABSTRACT FROM AUTHOR]

• Find out the exact cracking cause of the stator vane- a corrosion pit assisted fatigue. • The FE analysis showed the large von-Mises stress in the crack origin area under the wake excitation. • Pitting corrosion products, including the K 3 Al (SO 4) 3 , (Al 2 O 3)5(H 2 O), were characterized by XRD. • The stator vane had suffered from atmospheric corrosion during the aircraft downtime. A cracked third stage stator vane of the low-pressure compressor was found during a major overhaul of an aeroengine. The crack originated from a corrosion pit located on the arc transition between the leading edge and the upper edge plate. The finite element analysis results demonstrated the arc transition was the region with the large von-Mises stress under the wake excitation. The cleavage-like fracture and fatigue striations predominated throughout the fracture surface, indicating it was a pit-related fatigue crack. Meanwhile, Metallographic examination discovered most of corrosion pits beneath the bulging or peeling of the paint layer were distributed on the leading edge and the concave side. Moreover, the composition and phase identification results showed that the corrosion products included sulfate and alumina. Considering the pitting corrosion products and outdoor environment of the aircraft downtime, it was inferred that the cracked stator vane suffered from atmospheric corrosion. [ABSTRACT FROM AUTHOR]

In this paper, an environmentally friendly volatile corrosion inhibitor, lysine salts (LA), was prepared between graphene oxide (GO) layers by in situ intercalation technique and its corrosion inhibition effect was evaluated. The results indicated that the pore structure of GO facilitated the dispersion of LA molecules and improved the volatility. LA-GO2 achieved a 99.3% corrosion inhibition efficiency after composition optimization, mainly due to its significant inhibition of the electrochemical anodic process on the surface of mild steel. Moreover, the properties of the surface film on the corroded steel were also characterized in detail to reveal the corrosion inhibition mechanism of LA-GO2. • An effective and environmentally friendly volatile corrosion inhibitor is prepared by GO interlayer in situ modulation. • LA-GO2 has an excellent corrosion inhibition effect with a corrosion inhibition efficiency of 99.3%. • The porous flakes of GO better disperse the LA and improve its volatilization performance. [ABSTRACT FROM AUTHOR]

This study utilizes transfer learning (TL) to enhance long-term atmospheric corrosion predictions. Using a Fe/Cu galvanic-type sensor, we gathered data in a controlled SAE J2334 salt spray setting and transferred this to an uncontrolled outdoor environment. Among TL methods tested, freezing the initial layer and fine-tuning others at a lower rate was most effective. The approach excelled at forecasting outdoor corrosion behaviour using a limited dataset. This approach could provide a solution to extrapolate results from controlled corrosion tests to unpredictable outdoor conditions and addressing data scarcity in machine learning modelling in the context of atmospheric corrosion. • TL to extrapolate SAE J2334 data to outdoor settings using Fe/Cu ACM corrosion sensor. • Performance assessed by accuracy in predicting split I ACM intervals. • Optimal TL: freeze initial layer; fine-tune at 1 × 10−5 learning rate. • TL superior to benchmark models in cases of scarce outdoor training data. • TL model excels in detecting I ACM peaks vs. base model for a 1-week outdoor training data case study. [ABSTRACT FROM AUTHOR]

An electrical resistance sensor-based atmospheric corrosion monitor was employed to study the carbon steel corrosion in outdoor atmospheric environments by recording dynamic corrosion data in real-time. Data mining of collected data contributes to uncovering the underlying mechanism of atmospheric corrosion. In this study, it was found that most statistical correlation coefficients do not adapt to outdoor coupled corrosion data. In order to deal with online coupled data, a new machine learning model is proposed from the viewpoint of information fusion. It aims to quantify the contribution of different environmental factors to atmospheric corrosion in different exposure periods. Compared to the commonly used machine learning models of artificial neural networks and support vector machines in the corrosion research field, the experimental results demonstrated the efficiency and superiority of the proposed model on online corrosion data in terms of measuring the importance of atmospheric factors and corrosion prediction accuracy.

In this work, we used a combination of corrosion, electrochemical, and physical methods to determine the properties of nanoscale films obtained by treatment with octadecylamine (ODA), benzotriazole (BTA) vapors, and their mixtures at elevated temperatures. The mixture of ODA + BTA surpasses its components in protective aftereffect, but an analysis of their mutual effects shows that there is antagonism between them. Electrochemical impedance spectroscopy data indicate that the protection of steel by a mixture of ODA + BTA and its components is characterized by a mixed blocking activation mechanism. The processing of steel in hot vapors of the ODA + BTA mixture leads to hydrophobization of the surface and super-hydrophobization if a polymodal surface is created on the steel before processing in vapors.

Atmospheric corrosion can seriously affect the performance of steel structures over long periods of time; thus, it is essential to evaluate the rate of corrosion and subsequent modification of dynamic properties of a structure over different time periods. Standards and codes represent the general guidelines and suggest general protection techniques to prevent structures from corrosion damage. The available models in the literature propose the thickness reduction method that accounts for the exposure time of structures in corrosive environments. The purpose of this study is to review the existing corrosion models in the literature and report as well as compare their effectiveness in low (C2 level), medium (C3 level) and high (C4 level) corrosivity class in accordance with the ISO standard. Furthermore, the influence of corrosion loss during the lifetime of a structure is studied through a realistic case study model using FEM (finite element method) in both linear and nonlinear regions. The results showed that the corrosion can considerably affect the dynamic characteristics of the structure. For instance, the vibration period rose up to 15% for the C4 class and 100-year lifespan. Additionally, the corroded structure presented higher acceleration and drift demand, and the base reaction forces were reduced up to 60% for the same class and time period.