Atmospheric Corrosion Of Metals Research Articles

Influence of preliminary surface modification with organosilanes on atmospheric corrosion of metals

Influence of preliminary surface modification with organosilanes on atmospheric corrosion of metals

Effect of intermittent and continuous direct current electric fields on the initial corrosion of steel in simulated marine environment

Increasing cases of accidents caused by the corrosion of new energy power equipment have appeared in coastal areas. The corrosion of coastal power equipment is not only influenced by temperature, humidity, and corrosive ions, but also by strong electric fields. To further understand the effect of electric fields on the atmospheric corrosion of metals in the context of new energy, the effect of an intermittent direct current electric field and a continuous direct current electric field on the corrosion of carbon steel was investigated using weight loss curves, polarisation curves, X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS) techniques. The main corrosion products include Fe3O4, γ-FeOOH, and α-FeOOH in the Cl− solution. The results demonstrate that the continuous electric field (CEF) promotes the growth of γ-FeOOH and inhibits the transformation from γ-FeOOH to α-FeOOH, leading to the formation of a loose corrosion layer. This layer is conducive to the diffusion of dissolved oxygen and accelerates steel corrosion. Due to the short action time of the electric field in the intermittent electric field (IEF), γ-FeOOH cannot crystallise continuously and gradually transforms to α-FeOOH, which leads to poor penetration of the rust layer. Additionally, the time with no electric field is short; therefore, the precipitation and adsorption of chloride ions cannot be realised, and the IEF slows the corrosion rate.

Comparing Modelling and Experiments for Prediction of Atmospheric Corrosion Under Controlled Dynamic Thin Film and Droplet Electrolytes

Corrosion prediction by multiscale modelling aims to achieve the required paradigm shift in the lifetime prediction of metals. Modelling of atmospheric corrosion, for example, based on Finite Element Modelling (FEM) requires an exact description of the boundary region between metal and electrolyte. This requires a radically different research approach for the electrolyte in contact with the metal surface. The critical issue is that most corrosion experiments in fundamental research are performed “in solution” under the assumption that the electrolyte layer is thick enough to approximate it as “infinite”, ignoring significant local effects introduced by dynamic electrolyte dimensions caused by droplets and puddles. In other words, a major part of the research in academia is not relevant to mimic the actual conditions encountered on the metal surface. To create accurate numerical models, we first and foremost needed to abandon this "infinite" and “stationary” approximation and consider dynamic and finite electrolyte dimensions. During atmospheric corrosion of metals, the evolution of the thin-film electrolyte thickness is the primary factor determining the corrosion rate. A full understanding the evolution of the electrolyte thickness and properties as a function of the key environmental parameters is yet to be achieved. A novel methodology has been developed to conduct experiments under a regulated environment to measure the film thickness evolution or individual droplets on an undisturbed metal surface [1]. Experimental results are compared with FEM models predicting both the electrolyte formation as well as the related corrosion. The heat transfer coefficient is noted as a critical parameter influencing both the film characteristics and the resulting corrosion rate. This model was tested in case of cut-edge corrosion of galvanized steel. Combining the in-house MiTReM (Multi ion Transfer Reaction electrochemical model) with the electrolyte film thickness model, we could see that the corrosion rates become very critical in the range of 20 µm [2]. The next step was to go into the dimension of droplets. A thorough literature review [3] was made and published around modelling of droplet formation and corrosion, forming a base for further progress and improvements. The literature study also highlighted that the topic of droplet formation is relatively new within the corrosion research community. A new approach [4] was proposed to numerically predict and study atmospheric corrosion under droplet size distributions. The proposed methodology allows for a corrosion prediction based on observed droplet size distributions and droplet contact angles. A mechanistic finite element model, including oxygen transport and Butler-Volmer kinetics, is solved to obtain the current density for the droplet geometry. This is done for a range of both droplet radii and contact angles. The computed corrosion current densities are then adapted onto imposed droplet distributions for a calculation of overall corrosion current. This allows for a calculated material loss estimation for different distributions and electrolyte configurations and shows the extent of the impact of the droplet distribution on atmospheric corrosion. This model is validated by comparing with experiments introducing droplet-induced corrosion in a lab scale reactor that allows monitoring in parallel droplet geometry and corrosion as function of induced thermal cycles in a controlled atmosphere. Keywords: Atmospheric corrosion, FEM modelling, thin electrolyte films, droplets

Investigation of the importance of heat transfer during thin electrolyte formation in atmospheric corrosion using a novel experimental approach

During atmospheric corrosion of metals, the evolution of thin-film electrolyte thickness is the primary factor that determines corrosion rate. Understanding the evolution of the electrolyte thickness as a function of the key environmental parameters is yet to be achieved. Therefore, in the present article, a novel methodology has been developed to conduct experiments under regulated environment to measure the evolution of the film thickness on an undisturbed metal surface using an interferometer. Experimental results are compared with the previously developed simulation model. The heat transfer coefficient is noted as a critical parameter influencing the film characteristics and resulting corrosion rate.

Reliability assessment of strength resistance of circular steel - reinforce concrete conjugate column considering metal atmospheric corrosion

The bearing capacity of steel - reinforced concrete composite column depends on the geometrical dimensions, structural composition and mechanical properties of the material. In fact, these factors are random, especially when considering the atmospheric corrosion of metals. This paper presents the reliability assessment of strength resistance of circular steel - reinforced concrete composite column considering metal atmospheric corrosion. An uncertainty model is constructed based on the combination of deterministic design model according to Eurocode-4 with the input parameters and the corrosion model being random. The reliability of the column was assessed using Monte Carlo simulation method. The calculation program is built on Matlab platform allows the authors to conduct numerical surveys and draws conclusions and recommendations from the calculations results.

Influence of Coastal Atmosphere in the Corrosion of Components in Metallic Structures of Cuban Telecommunications Company (ETECSA) in Ciego de Avila, Cuba

Atmospheric corrosion of metals is an electrochemistry discontinuous process, which occurs only when the metal surface is wet or damp with various weather phenomena as rain, condensation, fog and other. NaCl is identified as one of the most aggressive pollutants for atmospheric corrosion to occur in coastal environments. Weather conditions in Cuba, together with its configuration and geographic location allow that the influence of the marine aerosol arrived to almost all the national territory favoring notably the deterioration of materials, especially the metallic ones. For this reason, it was decided to carry out a preliminary study of the effect of the coastal atmosphere on the corrosion of the components in metallic structures AT-60 and Najasa models of the Cuban Telecommunications Company (ETECSA) in Ciego de Ávila, Cuba. The selected components were subjected to micro and macro analysis. The coexistence of the loss of the paint layer with the onset of pitting corrosion was evidenced in the images observed by microscopy, while the results of the macro analyzes, only for components of the AT-60 model showed affectations, after one year of exposure, with decreases in the thickness of the metal between 50 and 100%, a loss of mass of 18.3% and perforations due to pitting corrosion that reached a diameter of up to 17 mm These reasons justified the need of a particular maintenance management in these zones.

Evaluation of the protective efficiency of a volatile corrosion inhibitor of atmospheric corrosion of metals in the presence of aggressive micro impurities of air by impedance spectroscopy method

The protective efficiency of the volatile IFHAN-114 corrosion inhibitor (VCI) was determined by impedance spectroscopy under atmospheric corrosion of St3 steel and copper in livestock buildings containing trace amounts of carbon dioxide, ammonia and hydrogen sulfide in the regulatory allowable concentrations. A 0.1 M NaCl solution was used as the background electrolyte. The effect of the combined presence of NH3 and CO2 corrosion stimulants of metals in the air was modeled by introducing (NH4)2CO3 in concentrations of 10 and 100 mg/L into the background solution. To simulate the combined presence of NH3 and H2S in air, equivalent amounts of Na2S and NH4Cl were introduced into the background electrolyte solution to obtain (NH4)2S (10 and 100 mg/L) at specified concentrations. This resulted in the hydrolysis of NH4+ and S2- ions to form NH4OH and H2S, which are stable in the surface phase film. According to impedance spectroscopy, (NH4)2CO3 at a concentration of 10 mg/L acts as an corrosion inhibitor of steel in a 0.1 M NaCl solution, and IFKHAN-114 (nonequivalent mixture of polyaniline with benzoic acid), introduced into the solution along with this amount of ammonium carbonate, plays the role of a corrosion stimulator. However, with an increase in the concentration of ammonium carbonate, its inhibitory effect is decreased, and for IFKHAN-114, introduced along with the salt, on the contrary, is appeared. A similar pattern is observed for the copper electrode. In the presence of (NH4)2S, almost the same effect of salt and VCI is observed for steel and copper, but with some variation. A comparison of the data obtained by gravimetric tests and impedance measurements showed that in the latter case only qualitative results can be obtained, although they undoubtedly confirm the presence of the inhibitory ability of IFKHAN-114 in a chloride neutral solution.

Corrosion Behavior of Q235 Steel in Atmospheres Containing SO2 and NaCl

The atmospheric corrosion of metals is a severe problem in marine environments. However, the effects of SO2 and NaCl on the atmospheric corrosion of Q235 steel have not been widely studied. In the present work, electrochemical impedance spectroscopy was conducted to exploit the initial corrosion properties of Q235 in simulated atmospheric environments containing different contents of SO2 and NaCl. The solution resistance (Rs) and polarization resistance (Rp) of electrodes covered with pre-deposited NaCl were continuously monitored. The results showed that both SO2 and NaCl promoted the corrosion rate of Q235 steel. The pre-deposited NaCl maintained the moisture of the metal surface to ensure continued corrosion. The thickness of the electrolyte layer on the metal surface decreased with increasing SO2 content. A thin electrolyte layer could increase the Cl− concentration and reduce the pH value of the layer. The thin electrolyte layer could also promote the mass transfer of oxygen, thereby accelerating the cathodic reduction reaction. However, the NaCl content played a more important role than that of SO2 in the simulated environments.

(Corrosion Division Morris Cohen Graduate Student Award) In-situ Monitoring of Ultra-slow Oxide Growth on Copper

The atmospheric corrosion of metals and alloys is a very complex process, which involves a wide range of chemical, electrochemical, and physical processes occurring in gas, liquid, and solid phases, as well as at the interfaces between them. Essentially all metals and alloys undergo corrosion in indoor or outdoor atmospheric conditions due to the presence of gaseous corrosion stimulators. However, the rate of the atmospheric corrosion might vary significantly depending on the nature of the metals or alloys, the concentration of corrosive species, as well as the exposure conditions. In some applications such as electrical contacts in microelectronics, military equipment or nuclear waste containers, even ultra-slow oxidation/corrosion may result in catastrophic consequences. In order to study such slow oxidation/corrosion processes, techniques involving ultra-high vacuum (UHV) are commonly used. Despite a very high surface sensitivity of these techniques they suffer from the drawback that the experiments are not performed under normal ambient conditions, but rather under vacuum. This has the consequence that the water adlayer which always exists on metal surfaces in atmospheric environments is removed under UHV conditions. Furthermore, in the case of ex-situ UHV studies, the structure of the oxidation/corrosion products might undergo vacuum induced changes. Hence, in-situ and highly surface sensitive techniques capable of working under atmospheric pressures are desired to monitor very slow oxidation and corrosion processes on metals and alloys at a molecular level. In the present study, several analytical techniques have been used to obtain a picture as complete as possible of an atmospheric corrosion process, focusing on both the formation of corrosion products and the evolution of the protective layer. Copper surfaces covered with protective organic monolayers have been exposed to various atmospheric environments with the aim of simulating typical indoor atmospheric corrosion processes. Infrared reflection/absorption spectroscopy (IRAS) was used to determine the nature of the corrosion products, quartz crystal microbalance (QCM) to measure the mass of them, and nano plasmonic sensing (NPS) to determine the corrosion rate as well as to evaluate how homogeneous the formation of the corrosion products was. In addition, an inherently surface sensitive technique, vibrational sum frequency spectroscopy (VSFS) was used to study induced changes in the molecular structure of the protective monolayers. VSFS studies of octadecanethiol (ODT) covered copper surfaces exposed to dry air allowed the detection of the formation of thin copper oxide layers and the observation of accompanying changes in the molecular structure of the hydrocarbon chains of ODT. VSFS was combined with QCM to quantify the amount of copper oxide formed on the surface. Since oxidation and corrosion processes often occur heterogeneously, the VSFS-QCM setup was integrated with NPS, which enabled us to distinguish homogeneous and heterogeneous corrosion under in-situ conditions with a time resolution on the order of seconds. This unique combination of three in-situ techniques facilitates the study of different corrosion processes where interfacial changes in electronic and optical properties as well as changes in mass occur. The sensitivity of the techniques under current exposure conditions corresponds to 5% of an oxide monolayer for VSFS, 2.5% for QCM, and 1.2% for NPS. As an extension of the above mentioned studies a combination of VSFS and IRAS was used to compare the corrosion protection efficiency of alkanethiol SAMs with different chain lengths and to compare SAMs with –S or –Se as their anchoring group when the samples were exposed to humidified air (HA) containing formic acid (FA). It was found that the corrosion inhibition efficiency of alkanethiol SAMs on copper was enhanced with an increased chain length. Furthermore, alkanethiol SAMs feature “selective hindrance” properties, i.e. they selectively allow the penetration of formic acid and oxygen and hinder the penetration of water resulting in the formation of copper formate and copper hydroxide. Interestingly, no formation of copper oxide was observed, which was in contrast to unprotected copper. VSFS revealed that SAMs of alkanethiols get more disordered over the course of sample exposure to HA+FA but remain attached to the substrate. Alkaneselenol SAMs initially behave similarly to their alkanethiol counterparts. However, after prolonged exposure to HA+FA they are partially removed from the surface, resulting in an accelerated corrosion of the copper substrate. Eventually, the corrosion products formed on alkaneselenol SAM covered samples consists of copper formate, copper hydroxide, and copper oxide. Figure 1

Atmospheric corrosion of metals in industrial city environment.

Atmospheric corrosion is a significant problem given destruction of various materials, especially metals. The corrosion investigation in the industrial city environment was carried out during one year exposure. Corrosion potential was determined using the potentiometric method. The highest effect of corrosion processes was observed during the winter season due to increased air pollution. Corrosion of samples pre-treated in tannic acid before the exposure was more difficult compared with the samples without pretreatment. The corrosion products determined with the SEM/EDS method prove that the most corrosive pollutants present in the industrial city air are SO2, CO2, chlorides and dust.

Effect of γ-FeOOH and γ-Fe2O3 on the Corrosion of Q235 Carbon Steel under Visible Light

In the present work, the influence of the photovoltaic effect of the corrosion products of γ-FeOOH and γ-Fe2O3 on the corrosion of Q235 carbon steel (CS) under visible light was qualitatively and quantitatively studied. The photo-voltages and photoinduced current density were simultaneously measured. The photoinduced holes generated by γ-FeOOH and γ-Fe2O3 capture the electrons from the anodic dissolution of the coupled Q235 CS, leading to the acceleration of the corrosion of the coupled Q235 CS. Although this work was performed in NaCl solution, the experimental results are useful to understand the influencing mechanism of light illumination on the atmospheric corrosion of metals.

Steel Corrosion Map of Vietnam

In the framework of an International cooperation program in Australia-Asia, the atmospheric corrosion of metals in five nations located in this tropical zone: Australia, Vietnam, Thailand, Philippines and Indonesia was investigated. In this program, mild steel, zinc and copper were tested on a set of sites, representative for different climatic conditions: severe marine, marine, industrial, urban and rural, simultaneously with the collection of climatic parameters and pollutants. Based on the data obtained in the Program and referring to the bank of data collected in the Vietnam National Projects, modeling was used to construct a corrosion map of steel for Vietnam. The correlation of the data derived from the map compared with those from National Projects is very high, in most cases, differing by less than 2-3%.

Corrosion Study of some Metals in an Urban Atmosphere

This study essentially deals with atmospheric corrosion of metals like Iron, Copper, Steel and Aluminium. Eight different locations based on various activities were selected. The results are discussed as functions of the type of location, test material, and exposure time. The results indicate that iron and copper were prone to elevated corrosion, while steel recorded medium level and aluminum the least corroded. Among the locations, Maddilapalem emerged as the site with the highest effect on metals in terms of corrosion. Furthermore, greater corrosion rates were observed in the Rushikonda area, close to the coast followed by Gajuwaka and Kancharapalem sites. The results of the study can be used to obtain a corrosion fingerprint of the locations included in the study. The study provides an insight into the pollution effects on metals and their location specific activities with reference to corrosion which can be applied for suggesting alternatives or control methods.

Atmospheric Corrosion of Metals in Ichihara Area

Atmospheric Corrosion of Metals in Ichihara Area

Prediction of Atmospheric Corrosion of Carbon Steel Using Artificial Neural Network Model in Local Geographical Regions

Abstract Atmospheric corrosion of metals is a complex, nonlinear process. It involves a large number of interacting and varying factors governed by material composition, form, size, testing procedu...

The Roles of the Width of Gas/Liquid/Solid Three-Phase Boundary Zone of Dispersion Water Films in Atmospheric Corrosion of Metals

The Roles of the Width of Gas/Liquid/Solid Three-Phase Boundary Zone of Dispersion Water Films in Atmospheric Corrosion of Metals

PREVENTION OF METALLIC CORROSION BY THIOCARBOHYDRAZIDES AND THEIR SALTS IN VAPOR PHASE ENVIRONMENT

There are several ways to prevent atmospheric corrosion of metals and alloys. The use of vapor phase corrosion inhibitors (VCIs) has advantages over classical methods of corrosion prevention due to its low cost, practicability, accessibility, and reliability. Few vapor phase corrosion inhibitors have been synthesized by the reaction of thiocarbohydrazides and organic acids. The VCIs inhibiting action on mild steel was investigated by weight loss and potentiodynamic polarization methods. Sodium chloride inoculation and sulfur dioxide (SO2) were also carried out. The corrosion-inhibiting properties of these compounds have been found to depend on the nature of organic acids and thiocarbohydrazides. Thiocarbohydrazide cinnamate salt exhibited >90% inhibition efficiency even at a concentration of 250 ppm. All the compounds investigated brought down the corrosion current significantly and showed predominantly anodic behavior.

Effect of Width of Gas/Liquid/Solid Three-Phase Boundary Zone of Discrete Water Film on Atmospheric Corrosion of Metals~!2009-10-12~!2010-05-01~!2010-08-09~!

Effect of Width of Gas/Liquid/Solid Three-Phase Boundary Zone of Discrete Water Film on Atmospheric Corrosion of Metals~!2009-10-12~!2010-05-01~!2010-08-09~!

Effect of low-molecular carbon acids on atmospheric corrosion of metals

A short review of studies on the atmospheric corrosion of metals in the presence of low-molecular carbon acids, as well as electrochemical studies aimed at elucidating the mechanism of acceleration of metal corrosion by low-molecular carbon acids are presented.

Atmospheric corrosion of metals in regions of cold and extremely cold climate (a review)

The results of atmospheric corrosion tests on a series of metals and alloys in marine and industrial atmospheres of the Earth’s regions with cold and very cold climate (Antarctic, sub-Arctic, Russian Far East) are considered. The class of most dangerous corrosive damage includes special types such as pitting, exfoliation corrosion, crevice corrosion and corrosion-induced cracking. Long-term prognosis is made concerning the influence of global warming on the atmospheric corrosion in cold climate regions.