scholarly journals Corrosion Performance of AISI-309 Exposed to Molten Salts V2O5-Na2SO4at 700°C Applying EIS andRpElectrochemical Techniques

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
E. F. Diaz ◽  
C. Cuevas-Arteaga ◽  
N. Flores-García ◽  
S. Mejía Sintillo ◽  
O. Sotelo-Mazón
Keyword(s):  
Molten Salts ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Metallic Surface ◽  
Corrosion Performance ◽  
Potentiodynamic Polarization Curve ◽  
Linear Polarization Resistance ◽  
Second Stage ◽  
Tafel Slopes ◽  
Bode Plots

The corrosion performance of AISI-309 exposed 5 days to molten salts 50 mol% V2O5-50 mol% Na2SO4at 700°C is reported in this paper. Such evaluation was made using three electrochemical techniques: potentiodynamic polarization curve (PC), electrochemical impedance spectroscopy (EIS), and linear polarization resistance (Rp). FromPC, the Tafel slopes,Icorr, andEcorrwere obtained. From Nyquist and Bode plots, it was possible to determine two different stages; the first one showed just one loop, which indicated the initial formation of Cr2O3layer over the metallic surface; after that, the dissolution of Cr2O3formed a porous layer, which became part of the corrosion products; at the same time a NiO layer combined with sulfur was forming, which was suggested as the second stage, represented by two capacitive loops. EIS plots were in agreement with the physical characterization made from SEM and EDS analyses. Fitting of EIS experimental data allowed us to propose two electrical circuits, being in concordance with the corrosion stages. Parameters obtained from the simulation of EIS data are also reported. From the results, it was stated that AISI-309 suffered intergranular corrosion due to the presence of sulfur, which diffused to the metallic surface through a porous Cr2O3layer.

Evaluation of Polymeric Coatings in CO2 Containing Environment

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 ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Polymeric Coating ◽  
Metallic Surface ◽  
Polymeric Coatings ◽  
X Ray Diffraction ◽  
X Ray ◽  
Linear Polarization Resistance ◽  
Weight Loss Method ◽  
Loss Method

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.

scholarly journals Corrosion Behavior of Fe40Al Alloy with Additions of Ti, Ag, and Cr in Molten KCl +ZnCl2

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
R. Ademar ◽  
J. G. Gonzalez-Rodriguez ◽  
J. Uruchurtu ◽  
J. Porcayo-Calderon ◽  
V. M. Salinas-Bravo ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Intermetallic Alloy ◽  
Corrosion Performance ◽  
Linear Polarization Resistance ◽  
Potentiodynamic Polarization Curves ◽  
Eis Measurements ◽  
The Stability

The effect of 2.5 at.% Cr, Ti, and Ag on the corrosion behavior of Fe40Al intermetallic alloy in KCl-ZnCl2(1 : 1 M) at 670°C has been evaluated by using electrochemical techniques. Techniques included potentiodynamic polarization curves, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) measurements. Results have shown that additions of both Cr and Ti were beneficial to the alloy, since they decreased its corrosion rate, whereas additions of Ag was detrimental, since its additions increased the corrosion rate, although the alloy was passivated by adding Ag or Cr. The best corrosion performance was obtained with the addition of Cr, whereas the highest corrosion rate was obtained by adding Ag. This is explained in terms of the stability of the corrosion products formed film.

scholarly journals Zeolites as reservoirs for Ce(III) as passivating ions in anticorrosion paints

2018 ◽  
Vol 36 (3) ◽  
pp. 305-322 ◽  
Author(s):  
Sol Roselli ◽  
Cecilia Deyá ◽  
Mariana Revuelta ◽  
Alejandro R. Di Sarli ◽  
Roberto Romagnoli
Keyword(s):  
Zinc Phosphate ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Electrochemical Techniques ◽  
Steel Electrode ◽  
Electrochemical Tests ◽  
Second Stage ◽  
Total Pigment ◽  
Anticorrosion Pigment

AbstractThe aim of this paper was to evaluate the performance of two different modified zeolitic minerals as anticorrosion pigments in order to reduce or eliminate zinc phosphate in paints. In the first stage, the selected minerals were characterized and modified with cerium ions to obtain the anticorrosion pigments. Their inhibitive properties were evaluated by means of electrochemical techniques (corrosion potential measurements and polarization curves) employing a steel electrode immersed in the pigments suspensions. In the second stage, solvent-borne paints, with 30% by volume of the anticorrosion pigment, with respect of the total pigment content, were formulated. The performance of the resulting paints was assessed by accelerated (salt spray and humidity chambers) and electrochemical tests (corrosion potential measurements and electrochemical impedance spectroscopy) and compared with that of a control paint with 30% by volume of zinc phosphate. Results obtained in this research suggested that zeolites can be used as carriers for passivating ions in the manufacture of anticorrosion paints with at least reduced zinc phosphate content.

scholarly journals Green Corrosion Inhibitors for Copper in HCl and H2SO4 Solution - A Review

2021 ◽  
Vol 9 (VI) ◽  
pp. 353-361
Author(s):  
R. T. Vashi
Keyword(s):  
Weight Loss ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Energy Dispersive ◽  
Effect Of Temperature ◽  
Metallic Surface ◽  
Electrochemical Impedance Spectra ◽  
X Ray ◽  
Surface Corrosion ◽  
Chemical Attack

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.

Comparison of Electrochemical Behavior of Cu-10Ni-10Zn Alloy and Cu in Aqueous Solutions

2015 ◽  
Vol 229 (3) ◽  
Author(s):  
Waheed A. Badawy ◽  
Mohamed M. El-Rabiei ◽  
Hashem M. Nady ◽  
Mohammed A. Samy
Keyword(s):  
Electrochemical Behavior ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Pure Copper ◽  
Open Circuit ◽  
Chloride Ions ◽  
Alloy Surface ◽  
Metallic Surface ◽  
Copper Dissolution ◽  
Basic Solutions

AbstractThe electrochemical behavior of Cu-10Ni-10Zn alloy and Cu was investigated in acidic, neutral and basic solutions. The effect of chloride ions in neutral solutions was also studied. Conventional electrochemical techniques and electrochemical impedance spectroscopy were used. The corrosion rate of these materials in acidic solutions is relatively high compared to that in neutral or basic solutions. The open-circuit potential of the alloy is nearly the same as that of pure copper in the different media, indicating that the processes which occur on the alloy surface are mainly governed by copper dissolution. In chloride solutions the rate of Cu corrosion is remarkably high. In the alloy, the copper dissolution was suppressed by the presence of nickel and zinc, due to the formation of complex oxide layers. The impedance data were fitted to equivalent circuit models that explain the different electrochemical processes occurring at the electrode/electrolyte interface. SEM and EDAX have shown that the alloy surface is enriched with Ni. In neutral solutions the chloride ions are penetrating the metallic surface.

scholarly journals Effect of Cu Addition on the Electrochemical Corrosion Performance of Ni3Al in 1.0 M H2SO4

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
J. Porcayo-Calderon ◽  
R. A. Rodriguez-Diaz ◽  
E. Porcayo-Palafox ◽  
J. Colin ◽  
A. Molina-Ocampo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Intermetallic Alloy ◽  
Intermetallic Alloys ◽  
Corrosion Performance ◽  
Linear Polarization Resistance ◽  
Electrochemical Corrosion Behavior

The effect of Cu addition on the electrochemical corrosion behavior of Ni3Al intermetallic alloy was investigated by potentiodynamic polarization, open-circuit potential, linear polarization resistance, and electrochemical impedance spectroscopy in 1.0 M H2SO4solution. Performance of the pure elements (Cu, Ni, and Al) was also evaluated. In general, Cu addition improved the corrosion resistance of Ni3Al. Electrochemical measurements show that corrosion resistance of Ni3Al-1Cu alloy is lower than that of other intermetallic alloys and pure elements (Ni, Cu, and Al) in 1.0 M H2SO4solution at 25°C. Surface analysis showed that the Ni3Al alloys are attacked mainly through the dendritic phases, and Cu addition suppresses the density of dendritic phases.

scholarly journals Effect of Nd3+ Ion Concentration on the Corrosion Resistance of API X70 Steel in Chloride-Rich Environments

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
D. M. Martinez de la Escalera ◽  
J. J. Ramos-Hernandez ◽  
E. Porcayo-Palafox ◽  
J. Porcayo-Calderon ◽  
J. G. Gonzalez-Rodriguez ◽  
...  
Keyword(s):  
Open Circuit Potential ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Protective Layer ◽  
Open Circuit ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Linear Polarization Resistance ◽  
Potentiodynamic Polarization Curves

In this study, the effect of the addition of Nd3+ ions as a corrosion inhibitor of the API X70 steel in a medium rich in chlorides was evaluated. The performance of the Nd3+ ions was evaluated by means of electrochemical techniques such as potentiodynamic polarization curves, open circuit potential measurements, linear polarization resistance, and electrochemical impedance spectroscopy, as well as by means of scanning electron microscopy and EDS measurements. The results showed that Nd3+ ions reduce the corrosion rate of steel at concentrations as low as 0.001 M Nd3+. At higher concentrations, the inhibition efficiency was only slightly affected although the concentration of chloride ions was increased by the addition of the inhibitor. The adsorption of the Nd3+ ions promotes the formation of a protective layer of oxides/hydroxides on the metal surface, thereby reducing the exchange rate of electrons. Nd3+ ions act as a mixed inhibitor with a strong predominant cathodic effect.

Use and Limitations of Electrochemical Techniques for Investigating Microbiological Corrosion

CORROSION ◽  
1991 ◽  
Vol 47 (4) ◽  
pp. 308-318 ◽  
Author(s):  
S. C. Dexter ◽  
D. J. Duquette ◽  
O. W. Siebert ◽  
H. A. Videla
Keyword(s):  
Electrical Resistance ◽  
Polarization Resistance ◽  
Electrochemical Noise ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Microbiologically Influenced Corrosion ◽  
Microbiological Corrosion ◽  
Pitting Potential ◽  
Linear Polarization Resistance ◽  
Cell Current

Abstract Electrochemical techniques such as: corrosion and critical pitting potential measurements, direct current potentiostatic and potentiodynamic polarization, linear polarization resistance, split-cell current measurements, electrochemical impedance, electrochemical noise, and electrical resistance probes are evaluated for use in investigating microbiologically influenced corrosion. Examples are given to illustrate the capabilities and limitations of each technique.

Corrosion Evaluation of Rust Converter and Microcrystalline Wax on Cannon Balls from San Juan de Ulua Fortress

2014 ◽  
Vol 1618 ◽  
pp. 227-232
Author(s):  
R. Orozco-Cruz ◽  
M. Ambros-Peralta ◽  
R. Galvan-Martinez ◽  
J. Reyes-Trujeque
Keyword(s):  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Metallic Surface ◽  
Marine Atmosphere ◽  
Efficient Tool ◽  
Corrosion Evaluation ◽  
Historical Heritage ◽  
New Compounds ◽  
Metallic Artifacts

ABSTRACTOne of the main problems encountered by curators and conservators in charge of metallic collections from Historical Heritage is related to their long-term conservation, since metallic artifacts undergo corrosion phenomena, which are the result of the interaction between the metal and its environment. The use of rust converters and microcrystalline waxes can be an ecological alternative to the traditional and more aggressive conservation techniques. Although the mechanism of action of these compounds is not clear, it is assumed that they react with iron oxides and generate new compounds that may have a passivation effect on the metallic surface. This paper proposes to show how simple electrochemical techniques can be used as an efficient tool to contribute to the diagnosis of the conservation state of cannon balls and to monitor the restoration treatment. The objective of the present work is to evaluate the effectiveness of a rust converter based on tannins and phosphoric acid, and one microcrystalline wax applied on cannon balls samples exposed to a marine atmosphere. The protection properties of the oxide or conversion layer are evaluated by electrochemical impedance spectroscopy (EIS) technique. The results obtained suggest that the use of the rust converter and microcrystalline wax protects the cannon balls, even though its effect is less evident when the deterioration degree is larger.

Diffusion of a Corroding Electrolyte through Defective Electroplated Ceria Based Coatings

2009 ◽  
Vol 289-292 ◽  
pp. 235-242 ◽  
Author(s):  
S. Poupard ◽  
F. Pedraza ◽  
J. Creus
Keyword(s):  
Cross Sections ◽  
Energy Dispersive Spectrometry ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Metallic Surface ◽  
Outward Diffusion ◽  
Metallic Substrates ◽  
Polarisation Resistance ◽  
Corrosion Mechanisms ◽  
Scanning Electron

Among the new environmentally friendly alternatives to improve the corrosion resistance of metallic substrates, cerium oxide based electrodeposited layers have raised particular attention. In this work, various electrodeposited layers on zinc substrate have been elaborated at different conditions to produce tailored compositions, microstructures and different degrees of porosity. The use of electrochemical techniques (polarisation resistance measurements, electrochemical impedance spectroscopy) has allowed to ascertain the porosity, which coupled to Scanning Electron Microscopy (FEG-SEM) and Energy Dispersive Spectrometry (EDS) studies along the cross sections have revealed the inward and/or outward diffusion of the different elements through the film till the metallic surface. The resulting corrosion mechanisms of these coatings immersed in 3% NaCl are finally discussed.

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