scholarly journals Controlling Atmospheric Corrosion of Weathering Steel Using Anodic Polarization Protection Technique

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1469
Author(s):  
Hany S. Abdo ◽  
Asiful H. Seikh ◽  
Ahmed Fouly ◽  
Faraz H. Hashmi

The atmospheric corrosion of weathering steels varies as a function of geographic zone, season, and other environmental variables related to that region which the experiments have been done. Meanwhile, rusting is a continuous process, and it is the main corrosion product of atmospheric corrosion. The current study investigates the effects of rust on weathering steel in the localized region of Digha, a sea resort of West Bengal, India. The investigations have been performed by purposely accelerating the rusting of weathering steel in a laboratory within one week in order to simulate approximately 18 months of actual rusting that can be achieved at field exposure. Anodic polarization of weathering steel comparable to potentiostatic passivation is obtained by shorting weathering steel with nobler metals, such as copper or graphite. The effect of rust formation on corrosion resistance after being immersed in 0.01 M KCl solutions for polished and unpolished samples has been investigated using electrochemical techniques, such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The rusted surfaces’ morphology and composition were characterized using field emission scanning electron microscope (FE-SEM) and energy dispersive X-ray analysis (EDX). Based on the obtained results, it is concluded that the progressive rusting of weathering steel leads to a decrease in corrosion rate.

2020 ◽  
Vol 98 (4) ◽  
pp. 169-178 ◽  
Author(s):  
M. Shehata ◽  
S.M. Azab ◽  
A.M. Fekry

The analysis and detection of caffeine (Caf) is very useful due to its widespread usage in several daily consumed beverages, food products, and pharmacological preparations with various physiological effects. The preparation of a newly electrodeposited Ag nanoparticles – cellulose acetate phthalate (CAP) – chitosan (Chit) modified carbon paste (ACCMCP) sensor for sensitive determination of Caf in 0.01 mol L−1 H3PO4 solution (pH 1.0–5.0) both in aqueous and micellar media (0.5 mmol L−1 SDS) was achieved. The interaction of Caf was monitored using electrochemical techniques such as cyclic voltammetry, differential pulse voltammetry, electrochemical impedance spectroscopy, and chronoamperometry, and surface characterization was carried out using X-ray diffraction, scanning electron microscope, and energy dispersive X-ray techniques. The linear detection range of Caf was between 4 and 500 μmol L−1 (r2 = 0.955) and the limit of detection obtained from the calibration plot was 0.252 μmol L−1. The sensor was applicable for detecting Caf in numerous real samples with recoveries from 98.03% to 101.60% without interference of any accompanying species, which ensures high method selectivity.


Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 591
Author(s):  
Ana Crespo ◽  
Iván Díaz ◽  
Delphine Neff ◽  
Irene Llorente ◽  
Sagrario Martínez-Ramírez ◽  
...  

The requirements for the formation of a protective patina on conventional weathering steels (WS) are well known in the scientific literature related to civil structures. However, these criteria are not always given due consideration when WS is used in cultural heritage, as in the case of sculptural work. An artificial patina was produced simulating artists’ working procedures using a direct patination technique, applying a solution of 10% H2SO4 on WS specimens. These were exposed for two years in the urban atmosphere of Madrid along with weathering steel specimens without artificial patina, called natural patina. The patinas generated have been analyzed using colorimetry, micro-Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and thickness measurements.The artificial patina color formed hardly differs from the color that the natural patina acquires from practically the beginning of its formation in the atmosphere of Madrid. After two years, the atmospheric corrosion rate of patinated WS is lower than 6 µm/year. The sulfuric acid treatment accelerates the protective ability of the patina with respect to the natural patina according to the ratio goethite to lepidocrocite (α/γ). Chromium-rich goethite is located in the inner part of the artificial patina as well as chromium-rich ferrihydrite. Ferrihydrite may act as a precursor of nanophasic goethite.


Author(s):  
Soyoung Jung ◽  
Thomas M. Devine

Two electrochemical techniques were used to investigate the corrosion of DLC coated magnetic hard disks: (1) potentiodynamic and potentiostatic anodic polarization and (2) electrochemical impedance spectroscopy. The objective was to determine the ability of DC polarization and AC polarization to detect the presence of porosity in the DLC. The results indicate that anodic polarization at high potentials (≈ +1.0V vs SCE) to cause pitting corrosion of the metal layers underneath the DLC might provide a rapid and quantitative estimate of the amount of porosity in the DLC. Measurement of the low frequency electrochemical impedance at intermediate potentials (≈ +0.5V vs SCE) appears to indicate the presence of porosity but further work is required to establish a quantitative relationship between the amount of porosity and the value of the low frequency impedance.


2009 ◽  
Vol 56 (6) ◽  
pp. 299-305 ◽  
Author(s):  
Xia Cao ◽  
Ning Wang ◽  
Ning Liu

PurposeThe purpose of this paper is to investigate the effect of chloride along with NO2 on the atmospheric corrosion of bronze using exposure tests.Design/methodology/approachSurface tension tests and electrochemical impedance measurements together with scanning electron microscopy (SEM) with energy dispersive atomic X‐ray, and X‐ray diffraction are used to characterize the corrosion behavior.FindingsThe results of the weight loss measurements show that the whole corrosion kinetics can be described approximately by: ΔW=atb; the synergistic effect of chloride and NO2 is observed clearly, though no nitrate existed in the corrosion products.Originality/valueA new catalyst theory has been suggested in this paper, i.e. that NO2 acts as a catalyst during the corrosion process when significant quantities of chloride also are present.


Author(s):  
R. T. Vashi

Corrosion is the deterioration of metal by chemical attack or reaction with its environment. It is a constant and continuous problem, often difficult to eliminate completely. Prevention would be more practical and achievable than complete elimination. Recently, a huge interested for the use of naturally occurring inhibitors extracted from plants have been emerged. Most of the natural products are non-toxic, biodegradable and readily available due to environmental concerns. The inhibitor is chemically adsorbed on the surface of the metal and forms a protective thin film with inhibitor effect or by combination between inhibitor ions and metallic surface. Corrosion of copper and its inhibition was analyzed by weight loss (Gravimetric), effect of temperature and time of immersion methods. Electrochemical methods such as, Potentiodynamic polarization and Electrochemical Impedance Spectra (EIS) were employed. The protective films formed on metal surface have been analyzed by various techniques such as Scanning Electron Microscope (SEM), Energy dispersive X-ray spectrometry (EDS) and. Atomic Force Microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), UV-Visible spectra, X-ray Diffraction spectroscopy (XRD), Energy Dispersive X-ray Spectroscopy (EDX), electrochemical frequency modulation (EFM) techniques. The results obtained from weight loss and electrochemical techniques were in good agreement. In this review paper, research works produced over the past background on the corrosion of copper in various medium and their corrosion inhibition by using a various green inhibitors were presented.


2015 ◽  
Vol 6 (1) ◽  
pp. 33 ◽  
Author(s):  
L. J. Reyes Jaimes ◽  
H. A. González Romero ◽  
A. Sandoval Amadora ◽  
D. Y. Peña Ballesteros ◽  
H. A. Estupiñán Durán

ResumenSe evaluó el efecto del pH de fluido corporal simulado en la formación de apatitas y en la degradación de superficies de la aleación Ti6Al4V recubiertas con Fosfato de Calcio mediante la técnica de lectrodeposición catódica. Como variables de estudio se tomaron el pH del fluido corporal simulado y el tiempo de inmersión de los recubrimientos. Mediante microscopia electrónica de barrido, espectroscopia de energía dispersiva, difracción de rayos X y absorción atómica se pudo corroborar la formación de apatitas, y la degradación de los recubrimientos se evaluó mediante Espectroscopia de impedancia electroquímica y curvas de polarización potenciodinámicas. Los resultados obtenidos muestran que los recubrimientos tenían altas concentraciones de Fluorapatita (Ca5(PO4)3F) y que su formación se ve favorecida a medida que el pH del fluido corporal simulado y el tiempo de inmersión aumenta. Por otra parte, se obtuvo que las muestras evaluadas a pH de 7,2 son menos estables termodinámicamente, sin embargo, las evaluadas a 7,6 presentan una superficie más activa, por lo que se obtiene una mayor velocidad de degradación. AbstractThe pH eect of a Simulated Body Fluid in the apatite formation and the degradation of the Ti6Al4V alloy surfaces, coated by calcium phosphate obtained through cathodic electrodeposition was evaluated. The simulated body fluid pH and the coating immersion time were taken as variables. The formation of apatite was corroborated by Scanning Electron Microscopy, Energy Dispersive Spectroscopy, X Ray Diraction and Atomic Absorption Techniques. The coating degradation was assessed by the Electrochemical Impedance Spectroscopy and the Potential Dynamic Polarization Curves. The results have shown that the coatings had high concentrations of fluorapatite (Ca5(PO4)3F) and its formation was favored as the simulated body fluid pH and the immersion time increases. Moreover, it was found that the coatings samples evaluated at pH 7.2 were less thermodynamically steady, however, the evaluated coating at pH 7.6 exhibited a more active surface, so that a higher rate of degradation is obtained.


2019 ◽  
Vol 965 ◽  
pp. 133-141
Author(s):  
Rayane Z.C. Demoner ◽  
Alexandre R.P. Castro ◽  
Adriana L. Barros ◽  
J.P. Quintela ◽  
Jefferson R. de Oliveira ◽  
...  

Two types of polymeric coating were applied on an AISI 1020 steel, where one of them was reinforced by carbon nanotubes, with the objective of protection against corrosion in a medium containing saline solution, NaCl 3% wt satured with CO2, at 75 bar and tested at 50oC and 75oC for 360 hours. Electrochemical techniques, such as Linear Polarization Resistance, (LPR), Electrochemical Impedance Spectroscopy (EIS), Tafel curves and weight loss method, were used for coating evaluation performance. Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) were used to determine both the morphology and chemical composition of the layer formed on the analyzed surfaces. The coating adhesion to metallic surface was evaluated using pull-off test according to ASTM D4541-09. For the studied conditions, the results obtained showed that there was no adequate coating protection, occurring failures and indicating that both coatings may not be used in the tested conditions.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
El-Sayed M. Sherif ◽  
Adel Taha Abbas ◽  
D. Gopi ◽  
A. M. El-Shamy

The corrosion and corrosion inhibition of high strength low alloy (HSLA) steel after 10 min and 60 min immersion in 2.0 M H2SO4solution by 3-amino-1,2,4-triazole (ATA) were reported. Several electrochemical techniques along with scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) were employed. Electrochemical impedance spectroscopy indicated that the increase of immersion time from 10 min to 60 min significantly decreased both the solution and polarization resistance for the steel in the sulfuric acid solution. The increase of immersion time increased the anodic, cathodic, and corrosion currents, while it decreased the polarization resistance as indicated by the potentiodynamic polarization measurements. The addition of 1.0 mM ATA remarkably decreased the corrosion of the steel and this effect was found to increase with increasing its concentration to 5.0 mM. SEM and EDS investigations confirmed that the inhibition of the HSLA steel in the 2.0 M H2SO4solutions is achieved via the adsorption of the ATA molecules onto the steel protecting its surface from being dissolved easily.


2016 ◽  
Vol 710 ◽  
pp. 216-221 ◽  
Author(s):  
Wagner Izaltino Alves Dos Santos ◽  
Isolda Costa ◽  
Célia Regina Tomachuk

New treatments for replacement of chromate require lower toxicity and corrosion protection. This study aims to investigate the influence of the combination of a Ce conversion coating (CCCe) with glycol molecules on the corrosion resistance of the AA2024-T3 clad (AA1230). The corrosion resistance of surface treated and untreated samples was evaluated by electrochemical techniques (electrochemical impedance spectroscopy, polarization tests and open circuit potential). These tests were complemented by salt spray tests to accelerate the corrosive effects of weathering. The surfaces were analyzed after corrosion tests by scanning electron microscopy with X-ray energy dispersive detector (SEM - EDX). The results of the CCCe samples in combination with glycol were compared with that of the surface with chromate layer and the results showed that the CCCe treatment is a candidate for replacement of chromating with the advantage that it does not generate toxic residues. The self-healing capacity of the new treatment tested was indicated by the increased formation of corrosion products deposition on top of Fe rich intermetallis in the AA1230 clad with time of exposure to the electrolyte.


CORROSION ◽  
10.5006/3936 ◽  
2021 ◽  
Author(s):  
Sara Filice ◽  
Joe McDermid ◽  
Joey Kish

The structure and composition of mill scale on linepipe steel formed with and without accelerated cooling conditions (ACC) was investigated and correlated to localized corrosion susceptibility. The mill scale structure/composition was investigated using scanning electron microscopy equipped with X-ray energy dispersive spectroscopy and electron back scatter diffraction, as well as X-ray diffraction. Localized dissolution of the mill scale was investigated using electrochemical techniques including open circuit potential measurements, electrochemical impedance spectroscopy, and electrochemical noise measurements in a corrosive phase solution. The various surface analytical and electrochemical techniques indicated that the mill scale formed without ACC consists of a relatively crack-free, thick inner wüstite layer with a thinner magnetite outer layer. However, the mill scale formed with ACC comprised a magnetite layer containing islands of retained wüstite, with some evidence of magnetite/iron eutectoid formation and which exhibited a relatively high density of through-scale cracks. These cracks can provide direct paths that connect the corrosive solution to the steel substrate, leading to more rapid breakdown of the mill scale. Additionally, the cracks can form a crevice between the mill scale and the steel surface, providing sites for pit initiation and growth. Coefficient of thermal expansion mismatch thermal stress calculations indicate that a magnetite-based scale is more susceptible to cracking/spalling than a wüstite-based scale, resulting in the ACC plate being more susceptible to localized corrosion.


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