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The characterization and evolution of corrosion products deposited on/around MnSs, a typical kind of inclusive particle embedded in AISI 304 stainless steel, was analyzed using a quasi-in-situ method in a 3.5 wt.% NaCl solution. On/around the MnS inclusion, a corrosion product layer with spinel Fe3−xCrxO4 as the main component was formed, with a thickness of several hundred nanometers. Below the layer, there was a cavity layer in which part of the MnS remained, forming secondary pitting along the MnS/matrix boundary. The mechanism of corrosion product deposition and evolution accompanied by MnS dissolution, as well as the characteristics of the corrosion products, are discussed. [ABSTRACT FROM AUTHOR]

The work examines the state of 106Ru in solutions simulating technological media and liquid radioactive waste from nuclear power plants with a VVER reactor, as well as the influence of the physicochemical state of the radionuclide on the efficiency of ion exchange and ultrafiltration treatment methods. During the study, the regions of existence of ionic and nonionic states of the radionuclide were explored in solutions of complex composition. In addition, the size distribution of particles containing 106Ru were established. The formation of complex compounds of 106Ru with polyborate ions in the neutral and slightly alkaline pH region has been shown, which leads to a decrease in the efficiency of decontamination of liquid radioactive waste from ruthenium radionuclides. [ABSTRACT FROM AUTHOR]

The paper presents the results of cobalt corrosion tests in air at different temperature and humidity values. It was demonstrated that corrosion losses in cobalt at temperatures of 20 and 30 °C and relative humidity of 70, 80, and 95% are insignificant. However, the rate of cobalt corrosion sharply increases at an air temperature of 50 °C, especially at 95% relative humidity. A conclusion about the intensity of the cobalt corrosion processes under these conditions can also be derived from the sample appearance: after testing at 50 °C and 70% humidity, the samples turn black, while at 50 °C and 95% humidity they become covered with black, oily, and easily crumbling flakes, which represent the products of cobalt corrosion. It was found that corrosion film formed on the cobalt surface consists of the eutectic Co–CoO mixture of variable composition and CoO·Co(OH)2·H2O complex oxide. At increased corrosion test temperatures, the surface film of hydrated cobalt oxide becomes thicker, develops microcracks, and leads to the formation of cobalt hydroxide flakes, which exhibit weak adhesion to the substrate and crumble. [ABSTRACT FROM AUTHOR]

Rare earth silicates are promising environmental/thermal barrier coating (E/TBC) materials facing severe CMAS (CaO‐MgO‐Al2O3‐SiO2) corrosion. Previous studies mainly focused on the intrinsic properties of precorrosion coatings, but there were few studies on their CMAS corrosion products that play a crucial role in the performance of coatings in postservice stage. In this work, the mechanical and thermal properties of nine corrosion products between lutetium silicates and CMAS are studied using first‐principles calculations. Their differences of elastic stiffness are attributed to the different crystal structures and bonding strength. The T:O ratio is identified as a factor of the crystal structure for silicate products, and it has a good correlation with their elastic stiffness. Moreover, the divergences of thermal conductivity are dominated by three essential factors, that is, atomic vibration intensity, lattice vibrational anharmonicity, and complexity of crystal structure. Compared with rare earth silicates, six products, that is, the α‐CaSiO3, β‐CaSiO3, Ca2MgSi2O7, Ca2Al2SiO7, CaAl2Si2O8, and Ca2Lu8(SiO4)6O2, showing good damage tolerance and low thermal conductivities, are predicted to be advantageous to E/TBCs. These discoveries reveal the mechanical/thermal properties of corrosion products between lutetium silicates and CMAS and are expected to support the future researches on the performance of E/TBC in the postservice stage. [ABSTRACT FROM AUTHOR]

Reinforced concrete structures play a key role in modern infrastructure, however, corrosion of reinforcement poses a serious threat to their durability and safety. In this study, the sensitivity of a portable X-ray fluorescence analyzer (XRF) to corrosion products on the concrete surface is considered. The experiment was conducted using concrete samples containing varying amounts of iron hydroxide. The results showed that the FRA demonstrates high accuracy and reliability in detecting corrosion, which contributes to the improvement of diagnostic methods and maintenance of reinforced concrete structures.

Autoclave corrosion testing has been used for many years; however, few have studied the effect of its shortcomings on the formation of corrosion products and corrosion behaviour. In particular, understanding of these effects under high temperature and high pressure (HTHP) is rare. In this study, we highlighted the important parameters such as heating periods, flow rates and volume-to-surface ratios influencing carbon steel corrosion in the early stages. Especially, characterisation and protection behaviour of corrosion products associated with corrosion behaviour in the heating stage under the geothermal CO2-containing environment were systematically studied via mass loss, in-situ electrochemistry and surface analysis techniques. The roles of pCO2, volume-to-surface ratio and flow rate influence the formation of the corrosion products in the early stage are also evaluated.

The findings of this study indicate that Cr-advanced steels exhibit increased corrosion resistance when Ni is incorporated into the alloy. To investigate this phenomenon, the corrosion products and corrosion behavior of Cr-advanced steels with varying Ni contents were evaluated in CO2-saturated NaCl solutions at 90 and 180 °C. The underlying corrosion resistance mechanism can be elucidated from two distinct perspectives. At 90 °C, the addition of Ni into Cr-advanced steels causes the transformation of Fe oxides to NiFe2O4, and it offers superior protection for steel. In addition, the NiFe2O4 phase generated with electronegative properties can enhance the adsorption of Fe2+, thereby promoting the precipitation of FeCO3 crystals. Furthermore, the residual Ni in the inner film continues to serve a pivotal role in the filling of a considerable number of pores and cracks. Upon comprehensive evaluation of the associated costs, the Cr-advanced steel with enhanced corrosion resistance through the incorporation of 1.0 wt% Ni content provides a potential alternative to a conventional 3Cr steel in a CO2 environment. On the other hand, at 180 °C, the concentrations of Fe2+ and CO32− are significantly higher than the solubility of FeCO3 in initial corrosion, which is conducive to generate a denser nanometer-size FeCO3 layer with a better protectiveness, and thus, the effect of Ni is significantly weakened.

Abstract HRB500E rebar is a low-alloy high-strength steel with excellent mechanical properties and good plasticity but suffers from deficient corrosion resistance. This can be solved by adding trace elements, including rare earth elements. Herein, the corrosion-resistant behavior of rebar was evaluated by weightlessness testing and electrochemical measurements, and the effects of Ce on the structural evolution of the corrosion product layer were investigated by scanning electron microscopy (SEM), Electron Probe X-ray Micro-Analyzer (EPMA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results showed that adding Ce to the rebar improved the densification of the reinforcing surface corrosion products, as well as reduced the corrosion rate of the experimental rebar. Compared to C0 sample without Ce, the rebar sample containing 0.044 wt.% Ce displayed increased Ecorr by 0.051 V, decreased Icorr by 15.573 mA cm−2, enhanced Rc of the corrosion product layer by 112.71 Ω cm2, incremented α-FeOOH content in the corrosion product layer, and boosted ratio of α/γ* in the corrosion product layer by 10.11%. Furthermore, the oxide (CeO2) formed by Ce in the corrosion layer of the rebar bar surface existed in the rust layer, resulting in a stable corrosion product layer with improved blocking ability of the corrosive medium. Overall, the addition of Ce at certain ratios looks promising to produce HRB500E rebar with excellent corrosion resistance and extended service life under harsh conditions.

HRB500E rebar is a low-alloy high-strength steel with excellent mechanical properties and good plasticity but suffers from deficient corrosion resistance. This can be solved by adding trace elements, including rare earth elements. Herein, the corrosion-resistant behavior of rebar was evaluated by weightlessness testing and electrochemical measurements, and the effects of Ce on the structural evolution of the corrosion product layer were investigated by scanning electron microscopy (SEM), Electron Probe X-ray Micro-Analyzer (EPMA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results showed that adding Ce to the rebar improved the densification of the reinforcing surface corrosion products, as well as reduced the corrosion rate of the experimental rebar. Compared to C0 sample without Ce, the rebar sample containing 0.044 wt.% Ce displayed increased Ecorr by 0.051 V, decreased Icorr by 15.573 mA cm−2, enhanced Rc of the corrosion product layer by 112.71 Ω cm2, incremented α-FeOOH content in the corrosion product layer, and boosted ratio of α/γ* in the corrosion product layer by 10.11%. Furthermore, the oxide (CeO2) formed by Ce in the corrosion layer of the rebar bar surface existed in the rust layer, resulting in a stable corrosion product layer with improved blocking ability of the corrosive medium. Overall, the addition of Ce at certain ratios looks promising to produce HRB500E rebar with excellent corrosion resistance and extended service life under harsh conditions. [ABSTRACT FROM AUTHOR]

The current work assessed the corrosion inhibitory efficacy of three ligands, namely methyl 2-((2-hydroxynaphthalen-1-yl)diazenyl)benzoate(MDN), 1-((3,4-dimethylphenyl)diazenyl)naphthalen-2-ol (DDN), and 3-((2-hydroxynaphthalen-1-yl)diazenyl)benzonitrile (HDN). Electrochemical and quantum methodologies, along with UV–Vis, SEM, and EDX, were employed. The anticorrosion process was comprehensively investigated. Potentiodynamic polarization validated the mixed type nature of inhibitors by demonstrating a drop in the cathodic hydrogen evolution reaction and the anodic metal dissolution, resulting to a significant decrease in corrosion current densities. Enhanced rates of effectiveness are achieved with higher inhibitor doses. Electrochemical impedance spectroscopy investigations confirmed the formation of a protective layer at the metal/solution interface, demonstrating that charge transfer was the primary cause of mild steel corrosion. The inhibitory potencies of the studied inhibitors at 10−3 M were 94.65, 94.56, and 93.63% for MDN, DDN, and HDN, respectively. The presence of several attributes in the molecular skeleton, such as nitrogen heteroatoms, aromatic rings, and the ester substituent group (CO2CH3), enhanced the availability of non-bonded and π-electrons and created stable covalent bonds by donating electrons to the iron surface. The inhibitory efficiency was better than 89% across all temperature ranges, suggesting the potential benefits of inhibitors at elevated temperatures. Adsorption trials revealed high effectiveness in corrosion control on mild steel, with Langmuir-based physisorption and chemisorption. The impact of electronegative O and N atoms, along with aromatic rings, in forming protective coatings was demonstrated by quantum chemistry computations which linked molecular structure and charge density patterns to the inhibition potency of MDN, DDN, and HDN, highlighting MDN's strong adsorption capacity. [ABSTRACT FROM AUTHOR]

Concentrated solar power (CSP) photothermal power generation technology utilizes renewable clean energy solar energy to convert thermal energy into electrical energy, offering promising application prospects. In CSP technology, molten salt serves as the medium for heat absorption and storage. Thus, the research and development of molten salt and salt storage materials are key. In this paper, the corrosion behaviors of different salt storage materials in molten salt media such as molten nitrate, carbonate, chlorine and fluoride salts were analyzed from the perspectives of corrosion kinetics, corrosion products and molten salt intrinsic properties. Finally, molten salt and salt storage materials for solar photothermal power generation were summarized, and the prospects were discussed.

Sacrificial metallic coatings are an effective strategy for mitigating corrosion in steel operating in industrial environments. This review article focuses on examining the protection mechanism of zinc-aluminum-magnesium (Zn-Al-Mg) coatings on steel substrates. Specifically, it investigates the effects of various elements and their corrosion products on the corrosion resistance of Zn-Al-Mg coatings. Furthermore, this review summarizes the formation mechanisms of various specialized corrosion modes that occur following the corrosion of Zn-Al-Mg coatings, based on previous experimental findings. It also includes suggestions for further research areas that could contribute to the development of highly corrosion-resistant and long-lasting coatings. These suggestions are based on published laboratory and field test results available in literature.

Corrosion has always been an important factor affecting the life of steel, which causes huge economic losses every year. How to improve the corrosion resistance of steel has always been a research focus. Adding rare earth elements into steel is an important method to improve the corrosion resistance of steel. In this paper, the effects of rare earth elements on steel are summarized, including the purification of molten steel, modification and modification of inclusions, improvement of grain boundaries by solid solution strengthening, the influence of phase transformation and the refinement of microstructure, and reduction in C and N desolubilization. On this basis, the progress of research on the corrosion resistance mechanisms of rare earth steel is summarized, focusing on rare earth-modified inclusions. This includes the changes in composition and sizes of inclusions by rare earth addition, promoting the transformation of MnS and Al2O3 in rare earth inclusions with regular shapes, smaller sizes and better performance, or composite rare earth inclusions. The corrosion pits that form in the early stages of corrosion are shallow in depth, fewer in number and light in corrosion degree. The effects of rare earth materials on the rust layer include: rare earth promotes the formation of a more stable corrosion product α-FeOOH, and rare earth promotes the formation of a dense rust layer, which covers the surface of the matrix and hinders the transmission of corrosion ions. The protective effect of the rare earth atomic layer on the substrate and the corrosion inhibition effect of rare earth ions are formed by the segregation of rare earth at the interface. In the end, the existing problems in the research into rare earth steel and future research directions are briefly put forward, including improving the addition process of rare earth steel, theoretical guidance on enhancing the corrosion resistance mechanism of rare earth steel, and extending the research from La, Ce, and Y steel to more rare earth steels. [ABSTRACT FROM AUTHOR]

For corrosive chloride solution, an excellent corrosion-resistant coating is required. In this view, introducing graphene oxide-modified Al 2 O 3 , TiO 2 , and MnO 2 in a nickel matrix is a novel strategy for achieving this goal. Electrodeposition is used for manufacturing these nanocomposite coatings. The microstructure, electrochemical corrosion resistance, composition, and contact angle are then thoroughly investigated. Electrochemical results revealed that Ni-GO-TiO 2 nanocomposite coating has a low corrosion current density of 10.86 μA/cm2 and a high charge transfer resistance of 2328 Ω cm2. Furthermore, the Ni-GO-TiO 2 nanocomposite coating outlasts pure nickel films. The mechanism of GO-TiO 2 -promoted nickel corrosion resistance turns out to be that GO-TiO 2 may impede the growth of nickel crystals and make them finer. Furthermore, this coating improves smoothness and reduces pores and cracks, resulting in less damage by chloride ions. Based on these findings, incorporating GO-TiO 2 into nickel coatings may provide insights into preventing corrosion of steel pipelines exposed to chloride ions. [Display omitted] • Nickel coating was reinforced with graphene oxide doped Al 2 O 3 , TiO 2 , and MnO 2. • Composition, crystal size, morphology, and hydrophobicity were compared. • Electrochemical and immersion tests were performed on all coatings. • Ni-GO-TiO 2 exhibited superior barrier performance due to improved properties. [ABSTRACT FROM AUTHOR]

In this work, two methods were used to accelerate the corrosion of concrete. In the first method, chloride ions were injected into the concrete using the migration method. The moment of the initiation of the corrosion process was monitored using an electrochemical method of measuring polarization resistance. In the next step, the corrosion process was accelerated by the electrolysis process. Changes on the sample surface were also monitored using a camera. In the second method, the corrosion process of the reinforcing bar was initiated by the use of the electrolysis process only. Here, changes occurring on the surfaces of the tested sample were recorded using two web cameras placed on planes perpendicular to each other. Continuous measurement of the current flowing through the system was carried out in both cases. It was assumed that in conditions of natural corrosion, a crack would occur when the sum of the mass loss of the reinforcing bar due to corrosion reached the same value in t c r (r e a l) (real time) as it reached in the t c r (time of cracking) during the accelerated corrosion test. The real time value was estimated for C1 concrete with cement CEM I. The estimated value was t c r (r e a l) = 1.1 years and for C2 concrete with cement CEM III, t c r (r e a l) = 11.2 years. However, the main difference that was observed during the tests was the nature of the concrete cracks. In the case of the C1 concrete sample, these occurred along the reinforcing bar, while in the C2 concrete, the failures occurred on a perpendicular plane transverse to the direction of the reinforcing bar. [ABSTRACT FROM AUTHOR]

This article discusses five bronze vessels from the funds of the Regional History Museum in Burgas dated to the 1st-3rd centuries AD. The aim of the analyses was the determination of the alloy used for manufacturing and the type of the corrosion products. The results were applied to some technological aspects regarding the manufacturing and the corrosion processes that occur in the vessels afterwards. The data gathered was later used to assign a proper conservation treatment and helpful to the restoration interventions. Unfortunately, the vessels were accidental finds therefore the interpretation of the results and the comparative analyses are not complete. [ABSTRACT FROM AUTHOR]

The characterization and evolution of corrosion products deposited on/around MnSs, a typical kind of inclusive particle embedded in AISI 304 stainless steel, was analyzed using a quasi-in-situ method in a 3.5 wt.% NaCl solution. On/around the MnS inclusion, a corrosion product layer with spinel Fe3−xCrxO4 as the main component was formed, with a thickness of several hundred nanometers. Below the layer, there was a cavity layer in which part of the MnS remained, forming secondary pitting along the MnS/matrix boundary. The mechanism of corrosion product deposition and evolution accompanied by MnS dissolution, as well as the characteristics of the corrosion products, are discussed.

An important method that coal-fired power plants use to realise low-cost zero discharge of desulfurisation wastewater (FGD wastewater) is to utilise wet slag removal systems. However, the high Cl− content of FGD wastewater in wet slag removal systems causes environmental damage. In this study, the corrosion behaviour of the inner guide wheel material, 20CrMnTi, was studied using dynamic weight loss and electrochemical methods. X-ray diffraction, scanning electron microscopy, and energy spectroscopy were used to analyse the organisational and phase changes on the surfaces and cross sections of the samples at different Cl− concentrations. The corrosion rate increased with the Cl− concentration up to 20 g/L, but it decreased slightly when the Cl− concentration exceeded 20 g/L. In all the cases, the corrosion rate exceeded 0.8 mm/a. The corrosion product film density initially increased and then decreased as the Cl− concentration increased. The corrosion products comprised mainly α-FeOOH, γ-FeOOH, β-FeOOH, Fe3O4, and γ-Fe2O3. [ABSTRACT FROM AUTHOR]

In this study, metal disks with different chemical composition (two Ag-based alloys and three Cu-based alloys) were buried in the soil of coastal archaeological sites for a period of 15 years. The aim was to naturally induce the growth of corrosion patinas to obtain a deeper insight into the role of alloying elements in the formation of the patinas and into the degradation mechanisms occurring in the very early stages of burial. To reach the aim, the morphological, compositional and structural features of the patinas grown over 15 years were extensively characterized by optical microscopy, field emission scanning electron microscopy coupled with energy dispersive spectrometry, X-ray diffraction and micro-Raman spectroscopy. Results showed that the Cu amount in Ag-based alloys strongly affected the final appearance, as well as the composition and structure of the patinas. Corrosion mechanisms typical of archaeological finds, such as the selective dissolution of Cu, Pb and Zn and internal oxidation of Sn, occurred in the Cu-based alloys, even if areas enriched in Zn and Pb compounds were also detected and attributed to an early stage of degradation. In addition, some unusual and rare compounds were detected in the patinas developed on the Cu-based disks. [ABSTRACT FROM AUTHOR]

The results of studies of the corrosion resistance of aircraft-grade aluminum alloys after two years of exposure to the coastal atmosphere of the moderately warm climate of Gelendzhik and the tropical climate of Wanning (Hainan Island, China) are presented. It is shown that the corrosive aggressiveness of the Gelendzhik atmosphere due to the location of the test beds in close proximity to the coastline and the more active influence of marine chlorides and sulfates is comparable to the corrosive aggressiveness of a tropical station. The emerging corrosion damage does not affect the tensile strength and yield strength of the materials under study, but reduce the relative uniform elongation of some of the studied alloys. [ABSTRACT FROM AUTHOR]

Internal carbon dioxide corrosion is one of the most common types of corrosion in gas field development. The results of studying the composition of carbon dioxide corrosion products by X-ray diffraction are presented. FeCO3 is the main product resulting from dissolution of steel upon carbon dioxide corrosion. Siderite is characterized by the phenomenon of isomorphism in the crystal structure (a change in the chemical composition of the phase at the same crystal structure). Here, some iron ions in FeCO3 can be replaced by manganese, calcium, and magnesium ions. It is found out that the phases of the formed precipitates with a nonstoichiometric composition (CaxMgyMnzFe)CO3 have poor crystallinity. This is associated with the presence of defects in the crystal structure. They will exhibit poorer protective properties when compared to stoichiometric FeCO3, the film of which is packed, uniformly distributed, and tightly adheres to the steel surface. An analysis of the diffraction patterns evidences good crystallinity of FeCO3, the shape of the particles of which tends to a regular hexagonal habitus. The results obtained can be used in studying the resistance of corrosion products formed on the internal surfaces of gas production equipment under aggressive conditions in the presence of CO2 in produced and transported hydrocarbons. [ABSTRACT FROM AUTHOR]

• Raman mapping is a powerful tool for analyzing iron corrosion products. • PLS, PCR and spectral fitting methods all show good accuracy on reference samples. • The spectral fitting method is more suitable for studying archeological iron corrosion due to the capability of identifying additional compounds. • This method is successfully applied in the conservation of iron artefacts from a shipwreck. The quantitative determination of corrosion products is essential for evaluating the corrosion state of archeological iron artifacts. This study explored two semiquantitative approaches using Raman mapping technique combined with chemometrics to quantify a binary mixture of magnetite and goethite. The first approach involved establishing quantification models using Raman spectra treated with Principal Components Regression (PCR) and Partial Least Squares (PLS) algorithms. Both the PCR and PLS model showed good predictive ability as indicated by correlation coefficients and root mean square errors (PLS: R c 2=0.9979, R p 2=0.9970, RMSEC=1.93, RMSEP =2.68, RMSECV=3.25). The second approach was based on spectral fitting using non-negative least squares (NNLS) algorithm. This method demonstrated a fair accuracy between the calculated and actual compositions. The absolute value of relative errors was 0.99%∼10.08% for Fe 3 O 4 and 0.81%∼9.71% for α-FeOOH respectively, for compositions greater than 20%. These methods were then applied to quantify the corrosion products on an iron bar excavated from the Nanhai (South China Sea) No. I shipwreck. Compared with XRD quantitative results, Raman results showed that the spectral fitting method was superior to the established PCA and PLS quantification models in both qualitative determination and quantitative accuracy. Compositional maps depicting the distribution of different phases were also generated using spectral fitting method. It was concluded that Raman mapping has significant potential as an accurate quantitative method for the detection of iron corrosion products, and that the spectral fitting method is more suitable for determining iron corrosion compared to the PCR and PLS quantification models in this study. [ABSTRACT FROM AUTHOR]

In France, deep geological disposal is considered for the storage of high and intermediate‐level long‐lived radioactive wastes. For aluminium, the possibility to encapsulate the wastes in a cement‐based matrix is studied. However, cement being an alkaline environment, aluminium can lose its passivity, starts to corrode leading to hydrogen evolution in the infrastructures and generate a possible explosive hazard after decades of storage if hydrogen can accumulate somewhere in the facility. It is therefore necessary to study the corrosion behaviour of aluminium in the different cements considered for the encapsulation to estimate the possible amount of hydrogen that could be generated through corrosion and design the cement capsules accordingly. This work mainly focused on the reaction occurring at the aluminium‐cement interface. Raman spectroscopy did not highlight significant differences in the nature of the corrosion products forming at the cement/aluminium interface, leading to the conclusion that it is not the chemistry of the cement that is the key factor controlling the corrosion rate but rather the physical properties of the cement matrix. [ABSTRACT FROM AUTHOR]

In order to control the radiation source term and reduce the collective dose during overhaul， the characterization methods such as scanning electron microscopy，focused ion beam transmission electron microscopy and positron annihilation were employed to study the effects of the oxidation operation process on the deposition behavior of corrosion products on the surface of the 690TT alloy in the steam generator of typical equipment.Results showed that a double-layer oxide film structure was formed on the surface of the 690TT alloy sample after pretreatment.The outer oxide layer was composed of nickel ferrite NixFe3－x O4， and the inner oxide layer was composed of chromium rich spinel NixFeyCr3－x－yO4.After short-term acid shutdown and oxidation operation， the sample exhibited a cross-sectional structure of the substrate， inner oxide film， outer oxide film and sediments.The inner oxide layer was chromium-rich， the outer oxide layer was partially dissolved， and the sediments were metallic nickel.During the oxidation operation stage， the solubility and redox status of metal elements on the sample surface were changed， promoting the dissolution of nickel ions on the sample surface， inhibiting the deposition of nickel elements on the sample surface， and significantly reducing the amount of sediments.Based on the experimental results， a dissolution deposition model on the surface of nickel-chromium-iron alloy was established.

To determine the composition of inhomogeneous samples using the method of laser-spark emission spectrometry, calibration dependences are used, which can have significant systematic errors that significantly affect the determination of the quantitative composition of elements. Sample inhomogeneity also causes inaccuracies in replicate measurements. To reduce errors, multi-signal calibration and internal standard methods are used, which can significantly improve accuracy when changing experimental conditions and eliminate the need to purchase ex-pensive standard samples.

In order to study the corrosion resistance and mechanism of a new type of acid resistant steel (LGNS-P) in sulfuric acid containing environments, Q345B carbon steel was used as a comparative material, and the corrosion behavior of two types of steels before and after the full immersion test was observed and tested through sulfuric acid accelerated corrosion test, corrosion weight loss analysis, SEM observation of corrosion morphology, and electrochemical potentiodynamic polarization tests. Results showed that the corrosion degree of LGNS-P was obviously less than Q345B, and the corrosion rate was gradually decreased during the test cycles. By contrast, the corrosion rate of Q345B increased first and then decreased, reaching its maximum after 240 h of testing. Compared to Q345B, the corrosion product layer of LGNS-P was more uniform and denser, which blocked the direct contact between corrosive ions and the substrate to some extent. In addition, there were some Fe oxides on the surface of both steels, but Sb oxides were also found on the surface of LGNS-P, which had certain acid resistance and could enhance the bonding ability of the corrosion product layer and the substrate. Overall, the above differences caused the significant improvement of acid corrosion resistance of LGNS-P

The effects of marine Streptomyces on the corrosion process of X65 steel were investigated by a complete characterization of metabolites using untargeted metabolomics, combined with surface analysis and electrochemical measurements. The results showed that the organic acid produced by Streptomyces accelerated the average corrosion rate of X65 steel in the early stage, but the formation of special “honeycomb” corrosion product structure promoted the enrichment of protein/polysaccharide in metabolites on the metal surface in the middle stage, and the biomineralized film was denser, which slowed down the corrosion especially localized corrosion. In the later stage, the corrosion was intensified due to the shedding of the protective film layer, but no obvious pitting corrosion was observed. In addition, the unique antimicrobial-like metabolites have potential applications in the field of microbiologically influenced corrosion inhibition by microbial control methods.

One of the main corrosive environments in gas processing is the moisture condensation condition in the vapor phase and variable wetting on the inner surface of equipment. In this case, steel microstructure and non-metallic inclusion content affect formation and development of corrosion defects of carbon and low alloy steels. It is shown that localization of carbon dioxide corrosion within a welded seam of X65 steel proceeds more intensively than within basic metal. Tests conducted in a specially designed stand under variable wetting conditions show that at the surface of 09Mn2Si steel local defects in the form of corrosion pitting occur in places where corrosion products are carried away. The morphology (density, continuity, etc.) of corrosion products (FeCO3) formed affects their potential barrier properties with respect to carbon dioxide corrosion of steel. Use of corrosion inhibitors prevents generation of local damage on steel under the action of media containing CO2. [ABSTRACT FROM AUTHOR]

One of the main corrosive environments in gas processing is the moisture condensation condition in the vapor phase and variable wetting on the inner surface of equipment. In this case, steel microstructure and non-metallic inclusion content affect formation and development of corrosion defects of carbon and low alloy steels. It is shown that localization of carbon dioxide corrosion within a welded seam of X65 steel proceeds more intensively than within basic metal. Tests conducted in a specially designed stand under variable wetting conditions show that at the surface of 09Mn2Si steel local defects in the form of corrosion pitting occur in places where corrosion products are carried away. The morphology (density, continuity, etc.) of corrosion products (FeCO3) formed affects their potential barrier properties with respect to carbon dioxide corrosion of steel. Use of corrosion inhibitors prevents generation of local damage on steel under the action of media containing CO2. [ABSTRACT FROM AUTHOR]

An effective strategy for achieving cost-effective and environmentally friendly desulfurization wastewater in coal-fired power plants involves the incorporation of desulfurization wastewater into the slag water system. The objective of this study was to analyze the corrosion behavior of Q235-A slag-picker shell material upon the introduction of FGD wastewater into the slag water system. The dynamic weight loss method, electrochemical testing method and microscopic phase characterization were employed to investigate the impact of varying chloride ion concentrations (ranging from 1000 mg/L to 30,000 mg/L) of flue gas desulfurization wastewater (FGD wastewater) on the corrosion of Q235-A slag-picker shell material. The test results indicate that as the concentration of chloride ions increases, the corrosion rate increases from 1.1487 mm/a to 1.5590 mm/a when the concentration is less than 10,000 mg/L. However, when the concentration exceeds 10,000 mg/L, the corrosion rate decreases from 1.559 mm/a to 1.0393 mm/a. The corrosion rate is above 1 mm/a at all concentrations. As the Cl− concentration, the quality of the corrosion product film initially increases and then decreases. The primary components of the corrosion product are α- FeOOH, γ-FeOOH, β-FeOOH, Fe3O4 and γ-Fe2O3. [ABSTRACT FROM AUTHOR]

The purpose of this research is to characterize and evaluate the corrosion behavior of zinc coatings used for corrosion protection, with a special focus on the S235 steel material. The introduction highlights the need for corrosion protection in industrial settings, as well as the importance of understanding corrosion processes and the development of corrosion products to develop more effective solutions. The study's goals are to undertake an extensive analysis of corrosion products formed on the zinc coating's surface, to evaluate the performance of these coatings under atmospheric circumstances, and to investigate the effect of deposition parameters on coating quality. The essential message provided to readers is the critical significance of knowing corrosion product formation mechanisms and zinc coating corrosion behavior in developing long-lasting and effective protection measures. The study methodology includes cycle testing, morphological and chemical examination of corrosion products, as well as optical and electron microscopy and energy-dispersive spectroscopy. Corrosion resistance is assessed using accurate measurements. The results show that zinc coatings have exceptional corrosion resistance under air settings, with the produced corrosion products offering further protection to the underlying material. Furthermore, the study demonstrates that the surface roughness of S235 steel has a substantial impact on the quality and corrosion behavior of hot-dip galvanized coatings. The findings emphasize the necessity of detailed characterization of corrosion products, the effect of depositional factors on zinc coating performance, and the need for novel corrosion protection methods. These discoveries have significant implications for the corrosion protection sector, providing the potential to improve the longevity and efficiency of protective systems used in industrial applications. [ABSTRACT FROM AUTHOR]

The corrosion behavior of Ni-Cr-Mo-V high strength steel in the simulated deep-sea environment under different hydrostatic pressure and immersion time is investigated using electrochemical techniques, microscopic morphology observation and Raman spectrometer. During the first 10 days immersion, the corrosion rate presents wave-like changes. The corrosion rate under different hydrostatic pressure tends to be stable after 10 days immersion. The area with uneven composition will preferentially dissolve and form corrosion pits. The local corrosion takes the corrosion pit as the center, expands and fuses around, and finally forms uniform corrosion. High hydrostatic pressure promotes β-FeOOH transforming into other corrosion products. The anode of the steel tends to active dissolution and the cathode show oxygen diffusion control characteristics at the initial stage of corrosion. Under 20 MPa, step-shape passivation appears in the anode region. Due to the rapid reaction, the corrosion product film has poor protection performance and dissolves, which resulting in not obvious passivation phenomenon.

In this work, two methods were used to accelerate the corrosion of concrete. In the first method, chloride ions were injected into the concrete using the migration method. The moment of the initiation of the corrosion process was monitored using an electrochemical method of measuring polarization resistance. In the next step, the corrosion process was accelerated by the electrolysis process. Changes on the sample surface were also monitored using a camera. In the second method, the corrosion process of the reinforcing bar was initiated by the use of the electrolysis process only. Here, changes occurring on the surfaces of the tested sample were recorded using two web cameras placed on planes perpendicular to each other. Continuous measurement of the current flowing through the system was carried out in both cases. It was assumed that in conditions of natural corrosion, a crack would occur when the sum of the mass loss of the reinforcing bar due to corrosion reached the same value in tcr(real) (real time) as it reached in the tcr (time of cracking) during the accelerated corrosion test. The real time value was estimated for C1 concrete with cement CEM I. The estimated value was tcr(real) = 1.1 years and for C2 concrete with cement CEM III, tcr(real) = 11.2 years. However, the main difference that was observed during the tests was the nature of the concrete cracks. In the case of the C1 concrete sample, these occurred along the reinforcing bar, while in the C2 concrete, the failures occurred on a perpendicular plane transverse to the direction of the reinforcing bar.

During the power operation of nuclear reactors, the corrosion products in the secondary circuit will deposit on the inside of Helical-coiled One-Through Steam Generator (H-OTSG) heat transfer tubes and form fouling. The main component of fouling is iron-based oxide, which generates from the heat exchangers made of cast iron. Fouling may change the local heat transfer characteristics of heat transfer tubes, and then affect the safety and economy of reactors. In order to obtain the distribution of fouling thickness and its action mechanism on helical tubes heat transfer characteristics, the heat transfer experiment under small pressurized reactors service environment was conducted. The experimental results indicate: corrosion products mainly deposit on onset of saturated boiling point with the maximum fouling thickness of 50 μm, and induce local wall temperature elevating about 773 K; fouling will increase the thermal equilibrium void fraction and hinder the heat transfer of helical tube, but has little impact on the onset position of saturated boiling point; corrosion products will release and re-deposit near dry-out point because of the flush of high speed vapor, causing the periodic fluctuation of thermal resistance of helical tube.

The reproduction of archaeological corrosion patinas is a key issue for the reliable validation of conservation materials before their use on cultural objects. In this study, bronze disks were intentionally buried for 15 years in the soil of the archaeological site of Tharros, both in laboratory and in situ, with the aim of reproducing corrosion patinas typical of archaeological artifacts to be used as representative surfaces for testing novel cleaning gels. The microstructural, microchemical and mineralogical features of the patinas were analyzed by a multianalytical approach, based on optical microscopy (OM), field emission scanning electron microscopy coupled with energy dispersive spectrometry (FE-SEM-EDS) and X-ray diffraction (XRD). The patinas developed in 15 years were compared with an archaeological bronze recovered from the same site after about two thousand years of burial (referred as short-term and long-term interaction, respectively). Results revealed a similar corrosion behavior, especially in terms of chemical composition and corrosion mechanisms. XRD detected the ubiquitous presence of cuprite, copper hydroxychlorides and terrigenous minerals, while OM and FE-SEM-EDS analyses of cross-sections evidenced similar patinas’ stratigraphy, identifying decuprification as driving corrosion mechanism. However, some differences related to the type of local environment and to the time spent in soil were evidenced. In particular, patinas developed in situ are more heterogeneous and rougher, while the archaeological one is thicker and presents a major amount of cuprite, terrigenous deposits and uncommon corrosion compounds. Based on our findings, the disks buried in situ were selected and used as disposable substrates to study the cleaning effect of a novel polyvinyl alcohol (PVA)-based gel loaded with a chelating agent (Na2EDTA · 2H2O). Results show that the gel is effective in removing disfiguring degradation compounds and preserving the stable and protective patina. Based on the conservation needs, the time of application can be properly tuned. It is worth noticing that after a few minutes the green corrosion products can be selectively removed. The EDS analysis performed on the gels after cleaning reveals that they are highly selective for the removal of copper(II) compounds rather than Cu(I) oxide or Cu(0) from bronze substrates.

Hyperbaric oxygen-accelerated corrosion testing (HOACT) is a newly developed method to study in the labor the corrosion behavior of steel bars in concrete. This work aimed to intensively investigate the mechanical properties and microstructures of HOACT-generated corrosion products by means of nano-indentation tests, Raman micro-spectrometry, and scanning electron microscopy. The local elastic modulus and nanohardness varied over wide ranges of 6.8–75.2 GPa and 0.38–4.44 GPa, respectively. Goethite, lepidocrocite, maghemite, magnetite, and akageneite phases were identified in the corrosion products. Most regions of the rust layer were composed of a complex and heterogeneous mix of different phases, while some regions were composed of maghemite or akageneite only. The relationship between the micromechanical properties and typical microstructural features is finally discussed at the micro-scale level. It was found that the porosity of corrosion products can significantly influence their micromechanical properties. [ABSTRACT FROM AUTHOR]

Corrosion is known as a breakdown effect that causes the deterioration of substances in enriched petroleum/gas conditions. This reaction occurs in all materials, which is highlighted in alloys. In the present study, the morphological properties, as well as the corrosion resistance behavior of the AISI1045 steel substrate coated with 321 austenitic stainless steel metal particulate fillers, were investigated. The electro-explosive spraying technique was employed to achieve a homogenous coating on the substrate surface. According to the results, the grain size of the 321 austenitic stainless steel coating layer was shrunk and reduced to 1–3 μm after the coating procedure. The coated layer also showed a homogenous and uniform thickness with an average value of 137 μm. Also, the average adhesion strength of 49.21 MPa was obtained between the sprayed coating and the substrate. The analytical analysis found the presence of Fe-Cr and Fe-Ni phases in the coating layer. The hardness of the original metal wire is 186 HV, and the microhardness of the coating after spraying is 232 HV. After subjecting the specimen to the corrosion examination, a 0.1961 mm/a corrosion rate was obtained for up to 120 h. Moreover, the corrosion products of CaCO3, Fe3O4, and MgFe2O4 were determined by XRD analysis. Furthermore, the observed results were further confirmed by the data obtained from EPMA and EDS evaluations. Hence, this study implies the beneficial role of electro-explosive sprayed alloy 321 austenitic stainless steel in creating a protective layer against corrosion on 45 steel substrate in an enriched oil/water environment. [ABSTRACT FROM AUTHOR]

The stability of drinking water distribution systems and the management of disinfection by-products are critical to ensuring public health safety. In this paper, the interrelationships between corrosion products in the network, microbes, and drinking water quality are elucidated. This review also discusses the mechanisms through which corrosive by-products from the piping network influence the decay of disinfectants and the formation of harmful disinfection by-products. Factors such as copper corrosion by-products, CuO, Cu2O, and Cu2+ play a significant role in accelerating disinfectant decay and catalyzing the production of by-products. Biofilms on pipe walls react with residual chlorine, leading to the formation of disinfection by-products (DBPs) that also amplify health risks. Finally, this paper finally highlights the potential of peroxymonosulfate (PMS), an industrial oxidant, as a disinfectant that can reduce DBP formation, while acknowledging the risks associated with its corrosive nature. Overall, the impact of the corrosive by-products of pipe scale and microbial communities on water quality in pipe networks is discussed, and recommendations for removing DBPs are presented. [ABSTRACT FROM AUTHOR]

The corrosion behavior and corrosion products of three zinc alloy‐coated steel substrates with different Al and Mg contents such as hot‐dip galvanized steel (HDG), Zn–Al‐coated steel (ZA), and Zn–Al–Mg‐coated steel (ZM) substrates were investigated during 168 h of immersion in 0.1 M NaCl solution. The characteristics and morphology of corrosion products on all the substrates formed during exposure to electrolyte solution were observed by X‐ray diffraction, X‐ray photoelectron spectroscopy, and scanning electron microscopy/energy‐dispersive X‐ray spectroscopy. Their electrochemical behavior was investigated by open‐circuit potential, polarization curves, and electrochemical impedance spectroscopy. The addition of Al and Mg alloying elements affected the corrosion mechanism as well as the anticorrosion properties. The main crystalline corrosion products on the HDG surface were simonkolleite and zincite, while the ZnAl hydrotalcite was identified as the main corrosion product on ZA and ZM surfaces. The corrosion resistance of ZA and ZM substrates was improved compared to the HDG substrate due to the enhanced adhesion of the corrosion product layer. [ABSTRACT FROM AUTHOR]

In this study, the formation and evolution of a corrosion product film on a 304 stainless steel exposed to an HCl pickling solution containing H2O2 were evaluated. Electrochemical polarization, spectroscopy, and characterization techniques including scanning electron microscopy, energy-dispersive x-ray spectroscopy, confocal laser scanning microscopy, and x-ray photoelectron spectroscopy were employed to investigate the characteristics of the corrosion product film and its effect on the corrosion of the stainless steel. The composition and structure of the corrosion product films were governed by the chemical oxidation of H2O2, which was dependent on the H2O2 concentration. The formation of a loosened CrCl3, FeCl2, and FeCl3 salt film occurs in the presence of 0.05-M H2O2. With a higher H2O2 concentration (0.15–0.60 M), the Fenton's reaction creates an environment for the production of chromium oxides and hydroxides. A compact film consisting of Cr(OH)3 and Cr2O3 covers the stainless steel. The dissolution of metal is then governed by the random availability of cation vacancies at the metal/film interface rather than the lattice structure of the metal, which contributes to the anodic brightening of the stainless steel. The compact film can dissolve in the HCl–H2O2 solution and transform into chloride salts again. Once the compact film breaks without self-repair, it causes a local attack at grain boundaries of the stainless steel. [ABSTRACT FROM AUTHOR]

In this study, thermal barrier coatings (TBC) consisting of 3.5 mol% Yb2O3-stabilized ZrO2 co-doped with 1 mol% Gd2O3 and 1 mol% Yb2O3 (referred to as GdYb-YSZ) were fabricated by means of air plasma spraying. The as-fabricated coatings exhibited a metastable tetragonal (t′) structure. The hot-corrosion behavior of the GdYb–YSZ TBCs was investigated at 700, 800, 900, and 1000 °C for 10 h in the presence of V2O5 molten salt. During the corrosion tests, the t′ phase transformed into a monoclinic (m) phase; nevertheless, it was still detected on the corroded surfaces. The amount of t′ phase decreased with increasing corrosion temperature. The corrosion products formed on the GdYb-YSZ TBCs in V2O5 comprised Yb, Gd-doped YVO4, and m-ZrO2, irrespective of the temperature of corrosion. However, higher temperatures changed the morphologies of the Yb- and Gd-doped YVO4 corrosion products. The GdYb–YSZ TBCs exhibited improved corrosion resistance to V2O5 molten salt when compared to YSZ TBCs, and the related mechanism is discussed in detail in this paper. [ABSTRACT FROM AUTHOR]

The effects of solute cerium (Ce) on the electrochemical performance of magnesium (Mg) alloy anodes are investigated by the weight loss test, electrochemical measurement, and surface analysis methods. It is found that the added Ce with the content of 0.174 wt.% enhances the corrosion resistance of Mg in seawater through forming the compact corrosion products layer and reducing the grain size of Mg alloys. Moreover, Mg-Ce alloys were applied in Mg-seawater batteries, which obtained a high energy density of 627.53 mWh g−1 with an anode efficiency of 43.49%, around 11 times than that of casting pure Mg. [ABSTRACT FROM AUTHOR]

Thirteen Late Roman copper alloy coins with a dark concretion layer from the Early Islamic period Ma‘agan Mikhael B shipwreck were chosen to undergo an experimental chemical cleaning and polishing procedure for removing the concretion while limiting the damage to the surviving metal. These coins, and two more without concretion discovered on the beach nearby, were then subjected to a series of non-destructive analyses–visual testing, XRF, multi-focal light microscopy, and Raman spectroscopy–to determine their state of preservation, identify their corrosion products, and acquire information regarding their core material. An additional coin was examined by destructive metallographic light microscopy and SEM-EDS analyses to gain further information concerning the concretion cover. Preservation varied: For some chemically cleaned coins, a shiny orange-coloured metallic surface was exposed, while others were poorly preserved. Moreover, evidence of the stamping process was also observed. The results show that the suggested chemical cleaning treatment could be useful for processing other copper alloy objects retrieved from underwater environments; we propose a 12-step methodology to this effect.

Chloride ion is an important corrosion factor in marine environment. Chloride ion has a small radius and strong permeability, which can destroy the oxide film on the surface of marine structural steel. The uneven adsorption of chloride ion on the metal surface will cause pitting corrosion. The effect of chloride ion content on pitting corrosion of the as-cast and heat-treated Dispersion-Strengthened-High-Strength (DSHS) steel was studied by electrochemical test, composition analysis and surface analysis. The results showed that high content of chloride ion reduced the content of dissolved oxygen in the solution, and the corrosion rate of DSHS steel was the slowest in 5.0 wt.% NaCl solution. In high content chloride ion solution, the formation of α-FeOOH was inhibited and the protection of corrosion products was weakened. Pitting corrosion of DSHS steel before and after heat treatment was the most serious in 2.0 wt.% NaCl solution. After heat treatment, grain size of DSHS steel decreased, and more dense and stable protective corrosion products were produced. Therefore, the induction and development of pitting corrosion of heat-treated DSHS steel were inhibited.