Atmospheric Corrosion Research Articles

Plasma in Situ Reduction of GO: Used to Improve the Atmospheric Corrosion Stability of Ag Mesh Flexible Transparent Conductive Electrodes

Plasma in Situ Reduction of GO: Used to Improve the Atmospheric Corrosion Stability of Ag Mesh Flexible Transparent Conductive Electrodes

Technology of production of aluminosilicate refractories for units processing fluorinated waste

The aluminium production process through the electrolysis of cryolite-alumina melts involves a series of interconnected, sequential, and parallel technological operations, each defined by a specific level of engineering and technological advancement. The development of the modern aluminum industry is closely tied to the adoption of resource-efficient and environmentally friendly technologies, which focus on recycling secondary materials and industrial waste. Fluorinated carbon-based materials release fluorine into the gas phase at relatively low temperatures when heated, and in thermal units processing fluorinated waste, this fluorine, along with alkali metals, will remain in the gas phase. To enhance the durability of furnace linings against the corrosive atmosphere, refractories with the highest possible density (low porosity) and a high concentration of mullite in the matrix (the finely ground component of the batch) are required. These properties can only be achieved in refractory products produced by the semi-dry pressing method, which ensures high grain packing density and leads to the formation of a ceramic mullite bond after firing.

Monitoring the anticorrosion performance of developed epoxy-based paint formulations on metallic surfaces by electrochemical impedance spectroscopy

Purpose This study aims to investigate the impact of varying solid ratios in epoxy-based formulations on their corrosion resistance. The amounts of epoxy resin in the formulations were kept constant, and the behavior of paints with varying filler ratios was compared. It also examines the tensiometric and rheological properties of these formulations. Design/methodology/approach Three distinct epoxy-based formulations cured with amine compounds were prepared. The formulations underwent various testing protocols to evaluate their performance: coating tests: coated panels with cross lines were exposed to humidity and corrosive atmospheres. Tensiometric Measurements: Conducted using pendant and sessile drop methods. Rheological characterizations: ıncluded flow tests, oscillatory amplitude sweeps and three-interval thixotropy tests. Corrosion resistance assessment: after the panels were immersed in methanol for one week, measurements were taken using electrochemical impedance spectroscopy. Additional tests: neutral salt spray (NSS) and humidity testing. Findings The study observed that the coated panels, after exposure to NSS and humidity testing, demonstrated corrosion resistance within acceptable limits as defined by the ISO 12944-6 standard. Results indicate that the epoxy-based formulations show potential for improvements in paints and coatings, suggesting promising advancements in their anticorrosion performance. Originality/value This research provides insights into how the solid ratios in epoxy-based formulations influence their performance, particularly in terms of corrosion resistance, tensiometric and rheological properties. The findings contribute to the development of more effective epoxy resin-based coatings for industrial applications.

Insights into the degradation mechanism of Fe-40Ni-15Co superalloy exposed to marine atmospheric and high-temperature conditions

This study investigated the corrosion and oxidation mechanism of the Cr-free Fe-40Ni-15Co superalloy with exposure to a tropical marine atmosphere for one year and a subsequent high temperature of 650 °C for 300 h. The degradation behavior of the samples was evaluated based on surface characterization and analysis. In the tropical marine atmospheres, the corrosion process of the Fe-40Ni-15Co superalloy presented an initial localized type after one month of exposure and gradually developed into uniform. The corrosion products were mainly comprised of Fe2O3 and NiO, suppressing the pitting process. During the high-temperature oxidation process, all samples presented super-parabolic oxidation kinetics. Except for the initial active oxidation due to salt deposits, the corrosion products after atmospheric exposure could significantly enhance the oxidation resistance at 650 °C. An explanation for the degradation mechanism of the Fe-40Ni-15Co superalloy was developed based on the synergistic effects of atmospheric corrosion and high-temperature oxidation.

ЦИНКНАПОЛНЕННЫЕ ПОКРЫТИЯ ДЛЯ ЗАЩИТЫ СЕЛЬСКОХОЗЯЙСТВЕННОЙ ТЕХНИКИ ОТ АТМОСФЕРНОЙ КОРРОЗИИ

Application of zinc-filled coatings (ZFC) on oil base is possible for protection of agricultural machinery from atmospheric corrosion. Analysis of literature has shown that anti-corrosion efficiency of ZFC largely depends on the size of zinc particles included in their composition. Zinc powders of different sizes PCR-1 (up to 40 μm) and PC-1 (up to 9 μm) in the amount of 40-60 wt.% were used for research. Oils were used: used motor oil (MMO), industrial oil I-20A, refined rapeseed oil and drying oil were used as a binder. It was determined that the corrosion potential (Ecor) of St3 steel with ZFC in 0.5 M NaCl solution occupies an intermediate value between the Ecor of steel and the Ecor of compact zinc. The concentration of Zn in the oil film as a result of its oxidation and transition to 0.5 M NaCl solution decreases over time from 40-60%, reaching almost the minimum value after 20 days. It was found that the introduction of zinc powder into oils increases their protective efficiency (Z) the more significantly, the smaller the particle size. The introduction of 40% PCR-1 powder increases Z MMO by 5%, and zinc PC-1 - by 48% in a saline solution. These trends are also preserved during tests in the G-4 heat and moisture chamber, but the difference when using different CNP is not as significant as during tests in a saline solution. The maximum Z = 93% was obtained for drying oil with 50% PCR-1; Z = 94- 95% for compositions with 50-60 wt.% PC-1 in rapeseed oil, Z = 94-95%. Coatings with PC-1 in MMO and rapeseed oil provide Z = 91% during full-scale bench tests over 12 months.

Research on mechanical property degradation model of equipment compartment floor under atmospheric corrosion condition

A mechanical property degradation model of material fatigue life varying with stress level and corrosion time was developed in this study. An acidified NaCl solution was used to accelerate the corrosion of stainless-steel samples, and the relationship between laboratory-accelerated corrosion and atmospheric corrosion was established using corrosion thickness loss parameters. Based on the results of a pre-corroded fatigue test, lgN–S–T surface models and a modified version of Miner’s rule for calculating nonlinear mechanical damage accumulation were proposed. Taking a real part of a high-speed train as an example, critical operating mileages considering material fatigue performance degradation under corrosion conditions were calculated, which were consistent with failure mileages of the census results.

Corrosion Properties of the Composite Coatings Formed on PEO Pretreated AlMg3 Aluminum Alloy by Dip-Coating in Polyvinylidene Fluoride-Polytetrafluoroethylene Suspension.

This paper presents the results of an evaluation of corrosion properties of PEO pretreated AlMg3 aluminum alloy samples with polymer coatings obtained by dip-coating in a suspension of superdispersed polytetrafluoroethylene (SPTFE) in a solution of polyvinylidene fluoride (PVDF) in N-methyl-2-pyrrolidone at different PVDF:SPTFE ratios (1:1, 1:3, 1:5, and 1:10). The electrochemical tests showed that samples with a coating formed at a ratio of PVDF to SPTFE of 1:5 possessed the best corrosion properties. The corrosion current density of these samples was more than five orders of magnitude lower than this parameter for bare aluminum alloy. During the 40-day salt spray test (SST) for samples prepared in a suspension at a PVDF:SPTFE ratio of 1:1-1:5, the formation of any pittings or defects was not detected. The PVDF:SPTFE 1:5 sample demonstrated, as a result of the 40-day SST, an increase in corrosion current density of less than an order of magnitude. The evolution of the protective properties of the studied samples was assessed by a two-year field atmospheric corrosion test on the coast of the Sea of Japan. It was revealed that the samples with the PVDF:SPTFE 1:5 coating had electrochemical parameters that remained consistently high throughout the one year of exposure. After this period, the polymer layer was destroyed, which led to a deterioration in the protective characteristics of the coatings.

Research Progress on Environmental Corrosion Resistance of Thermal Barrier Coatings: A Review

With the development of marine science and technology, marine construction is entering a new period of modern ocean development and utilization. The scale of marine development is expanding constantly. The lifespan of aircraft engines faces new challenges in marine environments. This paper reviews recent progress in the development of high-temperature coatings for aero-engines designed to resist marine atmospheric corrosion, with a focus on corrosion mechanisms, detection technologies, current research on marine atmospheric corrosion, standards for evaluating coating resistance, and novel advancements in coating materials.

Corrosion Behavior of 700L Automotive Beam Steel in Marine Atmospheric Environment.

The marine atmospheric corrosion behavior of 700L high-strength automotive beam steel exposed for 36 months was investigated by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and electrochemical technology. The corrosion kinetics of 700L steel followed the exponential function: D = 4.85t1.23. The rust layers were mainly composited of γ-FeOOH, α-FeOOH, γ-Fe2O3, and Fe3O4, regardless of the exposure duration. With an extended exposure time, the porosity, cracking, and spalling of the rust layers increased, and the densification and thickness uniformity decreased. Electrochemical measurements displayed that the corrosion resistance of the rusted 700L steel gradually decreased with increasing exposure time. A good correlation was found between rust layer composition, microstructure, and corrosion resistance.

Water vapor corrosion behavior of SiC-Al40Y ceramics fabricated by reactive melt infiltration and thermal diffusion

The corrosion resistance of Y-Al diffused SiC ceramics (SiC-Al40Y) at 1100-1300 °C was investigated. The results show that the weight gain curves comply with the parabolic fitting formula, then the oxidation rate constant and the activation energy were calculated to be 1.653×10-5 (1100 °C), 3.704×10-5 (1200 °C), 9.306×10-5 (1300 °C) mg2/cm4s and 154.7 kJ/mol. Compared with reported SiC (41-147 kJ/mol), the higher activation energy indicates the better corrosion-resistant performance. And it is found that the Y-Al diffusion layers can be transformed to corrosion-resistant YAlSixOy layers under corrosive atmosphere. Eventually, based on experimental results, the corrosion-resistant mechanism is analyzed: chemical potential gradient caused by preferential oxidation of Y-Al prompts the immigration of Y-Al from matrix to surface, gradually forming a continuous Y/Al-silicate layer on the surface and thus can hinder the further corrosion of H2O, O2.

Passivation of low-carbon steel with sodium dodecylphosphonate for protection against atmospheric corrosion

Passivation of low-carbon steel with sodium dodecylphosphonate for protection against atmospheric corrosion

Geo-mapping atmospheric corrosion in Mauritius

The complexity of atmospheric corrosion prediction in Mauritius, due to the influence of trade winds and mountainous landscapes, presents a hurdle in building a more resilient infrastructural system. In the absence of a corrosion map, the corrosion rate at a specific location is difficult to estimate. To achieve the UN Sustainable Development Goal 9 (Industry, Innovation and Infrastructure), an attempt is made to map the corrosivity of the whole country through regression modelling techniques and consideration of the factors affecting corrosion behaviour in the region. Previous field tests have recently been complemented with additional outdoor exposures to give a whole picture of the corrosivity of the Mauritian atmosphere. In this study, the relevant environmental data and known corrosion rates of carbon steel in specific locations are used to develop a corrosion map of the island as a vector data model depicting zones of specific ISO 9223 corrosivity categories.

Understanding the impact of alloying elements on weathering steel's atmospheric corrosion – A ten-year bridge exposure evaluation

This study assessed the atmospheric corrosion resistance of seven steel alloys, four custom-made and three commercially available, installed on a sheltered location on a bridge in Ontario-Canada. Visual inspection, SEM/EDS, thickness and weight gain measurement and electrochemical techniques were employed to investigate the protectiveness of patina. Results showed that small quantities of Cr, Mo, and P did not significantly improve the patina. Ni was effective, but the combination of Nb and B was crucial for enhancing it. Additionally, a linear correlation of average patina thickness and weight gain was observed for the alloys in this study.

Boosting corrosion resistance of Mg-Li alloy: Implanting bioinspired superhydrophobic surfaces into MAO matrix for enhanced protection

The corrosion problem has significantly impeded the practical application of Mg-Li alloys. In this report, a method that combines micro-arc oxidation (MAO) with electrochemical deposition is developed to create a superhydrophobic matrix on Mg-Li substrate. The combination approach harnesses the superiority of both coverages, including MAO as the dense, firmly bonded ceramic oxide layer on the metal substrate and the superhydrophobic surface (SHS) implanted into MAO matrix. The MAO-SHS coating exhibits high mechanical stability, maintaining the superhydrophobicity due to the “implanting effect” even after a long distance of friction effect. For corrosion inhibition, compared to the bare Mg-Li with icorr of 9.26 × 10−5 A/cm2, the icorr for MAO and MAO-SHS is 7.83 × 10−6 A/cm2 and 7.50 × 10−9 A/cm2, respectively, representing the reduction of approximately one and four orders of magnitude. Focusing the atmospheric corrosion inhibition, MAO-SHS proves to manipulate the dynamic evolution of saline solution evaporation and salt particle deliquation. The salt particle crystalized from saline solution on MAO-SHS is found to have significantly smaller contact area than that of the bare Mg-Li and MAO. By employing atomic force microscopy, the adhesion force of salt particle is revealed as ca. 45 nN, 13 nN, and 2 nN for salt particle on Mg-Li, MAO, and MAO-SHS, respectively. This suggests that the salt can be more easily removed from the MAO-SHS surface, thereby reducing the susceptibility to corrosion. The in situ deliquation is conducted to understand the formation of the droplet on different surfaces. The air in the SHS layer hinders chloride ingress and the SHS layer seals the pores in MAO layer, proving the synergistic effect afforded by MAO-SHS to achieve superior corrosion resistance.

Investigation of Corrosion Behavior of Cenosphere reinforced Iron Based Composite Coatings

In the present study cenopshere was reinforced with FeCrNiC (Metco 42C) as matrix material and prepared four different feedstock powders such as FeCrNiC+0%Cenosphere, FeCrNiC+5%Cenosphere, FeCrNiC+10%Cenosphere and FeCrNiC+15%Cenosphere were coated by plasma spray technique on T22 substrate. Evaluation of the substrate and coatings potential under salt spray test was performed. Dense fog of 5% NaCl salt water was used to create a corrosive atmosphere within the chamber. The salt water's pH was kept constant at 6.5-7. The materials that underwent corrosion were examined using X-ray diffraction (XRD), and scanning electron microscopy (SEM). The FeCrNiC+15%Cenosphere and FeCrNiC+10%Cenosphere coatings exhibited reduced weight loss during a 168-hour corrosion test compared to the FeCrNiC+5%Cenosphere, FeCrNiC coatings, and substrate. The excellent chemical stability and corrosion resistance of Cr23C6, SiO2, NiO, and Cr2O particles contribute to gradually avoid the formation of red rust on Fe-based coated samples with exposure approaches to 52 and 130 hours.

Thermodynamic evaluation of the aerial and aqueous oxidation of Al – Mg, Al – Si and Al – Mg – Si system alloys at 298 K

Aluminum and magnesium are the lightest structural metals, and therefore, various alloys based on them are widely used in both, automotive and aerospace industries. However, aluminum and magnesium are very easily affected by atmospheric and aqueous corrosion, and, therefore, the alloying elements should enhance their corrosion stability. In this work, the thermodynamic analysis of phase and chemical equilibria involving aluminum and magnesium alloys doped with silicon in oxygen–containing air environments, as well as the analysis of chemical and electrochemical equilibria involving these alloys in aqueous environments is conducted. The phase and chemical equiliibria in the Al–Mg, Al–Si, Mg–Si, and Al–Mg–Si systems at 298 K are considered, and the thermodynamic activities of the components of common Al–Mg–Si system alloys are calculated. The invariant chemical equilibria in the systems Al–Mg–O, Al–Si–O, Mg–Si–O at 298 K are considered, the isothermal section of the state diagrams of these systems are plotted, and the oxidation scheme of the Al–Mg–Si system alloys in excess oxygen is proposed. The chemical and electrochemical equilibria in the Al–Mg–Si–H2O system at 298 K are considered and presented in form of the activity – pH and the potential – pH diagrams, and the oxidation of the Al–Mg–Si system alloys in aqueous environments is discussed.

Structural frequency-based maintenance management method for steel truss bridges under atmospheric corrosion

Deterioration of steel truss bridges due to atmospheric corrosion can result in a degradation of performance that fails to meet basic safety requirements before the structure has fulfilled its design life. In order to prevent unexpected costs and premature structural damages caused by deterioration in steel truss bridges, cost-effective corrosion protection and maintenance strategies are required. In this study, a novel maintenance management method was proposed to keep the structural frequencies of steel truss bridges in between predefined boundaries throughout the service life. To pursue this aim, preventive and essential maintenance techniques were applied to provide appropriate atmospheric corrosion protection to steel truss bridges in a cost-effective way. Different repetitive repainting intervals were used for preventive maintenance, and member replacement alternatives with different ratios of total members were applied for essential maintenance approaches. Moreover, the replacement of members using conventional carbon steel, or A709-50CR was investigated separately. For the illustration of the proposed maintenance management method, a planar and a spatial steel truss bridge were selected from the literature, and maintenance strategies were applied considering two different corrosion classes. Life cycle cost analyses of steel truss bridges were conducted to evaluate different maintenance alternatives. Consequently, a cost-effective maintenance strategy was determined for each steel truss bridge in different corrosion environments.

Effect of Mo and Sn co-regulation on low alloy steel corrosion in tropical marine atmosphere

The influence of co-regulating Mo and Sn on the corrosion resistance of low alloy steel in tropical marine atmospheric was investigated. The combined addition of Mo and Sn has been found to significantly improve the corrosion resistance of low alloy steel, augmenting the protective capabilities of the rust layer. This combined addition promotes the formation of protective compounds like α-FeOOH and FeCr2O4 within the alloy rust layer. Furthermore, it facilitates the conversion of Cr, Ni and Cu into corrosion-resistant oxides such as Cr2O3, NiFe2O4 and CuO, thereby enhancing the density of the rust layer. Additionally, as corrosion progresses over time, higher levels of Sn addition lead to increased Sn content within the inner rust layer, consequently bolstering the protective qualities of the rust layer. This comprehensive understanding sheds light on the synergistic effects of Mo and Sn in fortifying the corrosion resistance of low alloy steel, offering insights for the development of advanced corrosion-resistant materials in marine environments.

Recent Progress on Atmospheric Corrosion of Field-Exposed Magnesium Alloys

It is well known that the poor corrosion resistance of magnesium alloys is a key factor limiting their application. Field exposure is the most reliable means to evaluate the atmospheric corrosion performance of magnesium alloys. This article reviews the field exposure corrosion behavior of magnesium alloys in typical atmospheric environments (including the marine atmosphere, industrial atmosphere, etc.) in recent years. According to the literature review, it was found that there are significant regional differences in the atmospheric corrosion behavior of magnesium alloys, which is the result of the coupling of multiple factors in the atmospheric environment. By investigating the corrosion rate and corrosion products of different types of magnesium alloys in different environments, the corrosion mechanism of magnesium alloys in different environments was summarized. Specifically, environmental parameters such as atmospheric temperature, relative humidity, CO2, and chloride ion deposition rates in the marine atmospheric environment can affect the corrosion behavior of magnesium alloys. The corrosion of magnesium alloys in different industrial atmospheric environments is mainly affected by atmospheric temperature and relative humidity, as well as atmospheric pollutants (such as SO2, CO2, NO2) and dust. This review provides assistance to the development of new corrosion-resistant magnesium alloys.

Analysis and Estimation of Atmospheric Corrosivity of Zinc Protective Coating on Steel Substrate

Analysis and Estimation of Atmospheric Corrosivity of Zinc Protective Coating on Steel Substrate