Electrochemical Study of 1018 Steel Exposed to Different Soils from South of México

2015 ◽  
Vol 1766 ◽  
pp. 81-94 ◽  
Author(s):  
L. M. Quej-Ake ◽  
A. Contreras
Keyword(s):  
Corrosion Rate ◽  
Moisture Content ◽  
Potentiodynamic Polarization ◽  
Electrochemical Impedance ◽  
The State ◽  
Polarization Curves ◽  
High Plasticity ◽  
Coated Steel ◽  
Potentiodynamic Polarization Curves ◽  
Physicochemical Effect

ABSTRACTPhysicochemical effect on the corrosion process of AISI 1018 steel exposed to five type of soils from South of México at different moisture content using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves was studied. Two soils were collected in the state of Veracruz (clay of high plasticity and silt) and three soils from the state of Campeche (sand, clay and clay-silt). Moisture values were determined by addition of 0, 20, 40 and 60 ml of deionized water in a volume of 125 cm3of each soil. The corrosion behavior of uncoated and coated steel with a viscoelastic polymer was analyzed. Effect of damage on the coating when the steel is exposed to corrosive soils was studied. EIS evaluations indicate that 1018 steel without coating is more susceptible to corrosion in the clay at the maximum moisture content (39.7 wt. %). However, for sand the more corrosive moisture belong to 12.8 wt. %, which is not the maximum moisture, which is agree with the lower polarization resistance (52.21 Ω.cm2). Potentiodynamic polarization curves suggested that uncoated steel exposed to clay-silt from state of Campeche exhibited the higher corrosion rate (0.698 mm/year) at 53.1 wt. % moisture. Meanwhile, in the coated steel with induced damage, the higher corrosion rate was obtained in the clay (0.0018 mm/year) at 34.2 wt. % moisture. 1018 steel coated with induced damage exposed to clay displayed the higher Ecorrvalues, which means that clay is more susceptible to overprotection as consequence of any change in the voltages originated by moisture content.

Studies on Corrosion Behavior of S-165 and HP Supermartensitic Stainless Steels in Cl- Environment

2011 ◽  
Vol 695 ◽  
pp. 425-428
Author(s):  
Duo Wang ◽  
De Ning Zou ◽  
Chang Bin Tang ◽  
Kun Wu ◽  
Huan Liu
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Corrosion Behavior ◽  
Stainless Steels ◽  
Potentiodynamic Polarization ◽  
Electrochemical Impedance ◽  
Polarization Curves ◽  
Chemical Compositions ◽  
Pitting Potential ◽  
Potentiodynamic Polarization Curves

Supermartensitic stainless steel grades are widely used in oil and gas industries to substitute duplex and super duplex stainless steels these years. In this paper the corrosion behavior of supermartensitic stainless steels with different chemical compositions, S-165 and HP, was investigated in Cl-environment. All the samples were treated by quenching at 1000 °C followed by tempering at 630 °C for 2h. After heat treatment, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) were determined on both kinds of samples. Polarization curves shows that the metastable pitting nucleuses were formed in passive area and the Cr content is the most important factor leading to the differences of pitting potential. The potentiodynamic polarization curves were conducted at various NaCl contents (5000, 15000 and 35000 ppm) and emphasized the need to account for the Cl-sensitivity of samples under corrosion environment. The results show that, the pitting potential decrease with the increase of chloride contents. The behavior of passive film was analyzed by electrochemical impedance spectroscopy.

Formation of Corrosion Resistant Hard Coating of Litao3 by Anodizing in Molten Lino3

2019 ◽  
Vol 9 (1) ◽  
pp. 50-59
Author(s):  
Likun Hu ◽  
Sicheng Yuan ◽  
Panping Xie ◽  
Dengfeng Xu ◽  
Zhi Peng ◽  
...  
Keyword(s):  
Thin Film ◽  
Anodic Oxidation ◽  
Potentiodynamic Polarization ◽  
Electrochemical Impedance ◽  
Surface Hardness ◽  
Open Circuit ◽  
Polarization Curves ◽  
Electrochemical Impedance Spectra ◽  
Potentiodynamic Polarization Curves ◽  
Pure Tantalum

Background: Lithium tantalate (LiTaO3) thin film was synthesized and in situ coated on tantalum substrate via anodic oxidation. Methods: The effects of temperature, voltage and time on composition, morphology and hardness of film were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Vickers hardness, respectively. Results: Our results showed that surface hardness of all coated samples has been increased compared with that of pure tantalum. The value of hardness was found to gradually increase with temperature, voltage and reaction time of the coating process. Selected specimens, after coating, were immersed into 10 wt% NaOH solution at 50oC for 96h to explore their anti-corrosion performance. Immersing results indicated that LiTaO3 coated samples have a smaller mass loss and corrosion rate compared to those of pure Ta substrate. Pure tantalum sample and those coated by LiTaO3 thin film were further examined by electrochemical methods including open-circuit potential (OCP), potentiodynamic polarization curves and electrochemical impedance spectra (EIS). Conclusion: We have found that samples coated with LiTaO3 thin film exhibit higher potentials and lower corrosion current densities than those of pure tantalum substrate, according to the results and analysis of OCP curves and potentiodynamic polarization curves. Upon anodic oxidation, samples display higher polarization resistance with higher resistance to corrosion.

Corrosion characteristics of carbon steel in solutions of synthetic detergents

2020 ◽  
pp. 112-115
Author(s):  
I.A. Strel’nikov ◽  
D.A. Pestryaev ◽  
Sh.V. Sadetdinov
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Aqueous Solutions ◽  
Corrosion Fatigue ◽  
Potentiodynamic Polarization ◽  
Cyclic Strength ◽  
Fatigue Tests ◽  
Polarization Curves ◽  
Positive Side ◽  
Potentiodynamic Polarization Curves

Data of corrosion rate are obtained experimentally, values of braking coefficient, protection degree of steel 10 in 3 % aqueous solutions of detergents ML-52, MS-8 and Labomid-203 are calculated. It is found that when the composition of synthetic detergents diethylene tetraborate ammonium (DETA) composition (NH4)2B4O7·2C2H8N2·2H2O concentration of 0.5 % wt., the corrosion rate of carbon steel is significantly reduced, and the values of the braking coefficient and the protection degree increase and reach almost significant values. By removing the potentiodynamic polarization curves, it is shown that in the presence of DETA, the dissolution potentials of steel 10 are shifted to the positive side relative to the potential in the background solutions and the anode process is predominantly slowed down. Corrosion-fatigue tests indicate increase in the coefficient of cyclic strength reserve of carbon steel in aqueous solutions of synthetic detergents with the addition of DETA. The results allow us to recommend the compound diethylene tetraborate ammonium as effective anticorrosive additive to synthetic detergents used to clean parts from technological contaminants in the repair of process metallurgical plants machines.

Corrosion Behavior of Al-Sn-Bi Alloys in Ethylene Glycol-Water Mixtures

CORROSION ◽  
2012 ◽  
Vol 68 (5) ◽  
pp. 421-431
Author(s):  
J.L. Gama-Ferrer ◽  
J.G. Gonzalez-Rodriguez ◽  
I. Rosales ◽  
J. Uruchurtu
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Corrosion Rate ◽  
Ethylene Glycol ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Electrochemical Noise ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Potentiodynamic Polarization Curves

A study of the effect of Sn (1, 2, 3.5, 4.5, and 5 wt%) and Bi (0.5, 1.5, 3, and 4%) on the corrosion behavior of Al in ethylene glycol (C2H6O2)-40% water mixtures at 20, 40, and 60°C has been carried out using electrochemical techniques. Techniques include potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), and electrochemical noise (EN) measurements. The three techniques have shown that additions of either Sn or Bi contents increased the corrosion rate of pure Al in all cases, and that generally speaking, the corrosion rate increased by increasing the temperature except for the alloy containing 1% Sn + 4% Bi, which showed the lowest corrosion rate at 60°C. This was because of a galvanic effect from the presence of Sn and/or Bi particles on the surface alloy, which acted as local cathodes, leading to an acceleration of corrosion. Nyquist diagrams showed two semicircles at 20°C and only one at 40°C or 60°C for all the alloys, showing two different corrosion-controlling mechanisms. EN measurements showed evidence of a mixture of both localized and uniform types of corrosion for all Al-based alloys.

scholarly journals Corrosion Inhibition of Mild Steel in 1.0 M HCl Solution by Anhydrous Tricalcium Phosphate

2018 ◽  
Vol 12 (1) ◽  
pp. 68-81 ◽  
Author(s):  
L. Chafki ◽  
E.H. Rifi ◽  
R. Touir ◽  
M. Ebn Touhami ◽  
Z. Hatim
Keyword(s):  
Mild Steel ◽  
Potentiodynamic Polarization ◽  
Tricalcium Phosphate ◽  
Electrochemical Impedance ◽  
Physical Adsorption ◽  
Protective Layer ◽  
Polarization Curves ◽  
Metallic Surface ◽  
Potentiodynamic Polarization Curves ◽  
Hcl Solution

Objective: In this study, electrochemical measurements were used to characterize Anhydrous Tricalcium Phosphate (ATP) as a corrosion inhibitor for mild steel in 1.0 M HCl. Method: The potentiodynamic polarization curves indicated that the ATP reacts as an anodic type inhibitor. In addition, it has been found that the electrochemical impedance confirms the inhibitor character of ATP obtained by the potentiodynamic polarization curves where the inhibition efficiency increases by its concentration to reach a maximum of 93.79 % at 10-4 M. The temperature solution influence indicated that the corrosion rate increases with temperature while the inhibitor acts actively. Thermodynamic adsorption and activation parameters indicated that the ATP acts by physical adsorption on the metallic surface with an endothermic process of metal dissolution. Result: Additionally, it was found that the adsorption of ATP molecules obeyed to the Langmuir isotherm. Surface analyses via scanning electron microscopy (SEM) was used to investigate the morphology of mild steel before and after immersion in 1.0 M HCl solution without and with 10-4 M of ATP. It is revealed that the ATP  acted by the formation of a protective layer on the mild steel.

Corrosion Inhibition of Sodium Hexametaphosphate for Carbon Steel in KCl Solution

2014 ◽  
Vol 886 ◽  
pp. 12-15
Author(s):  
Bin Huang ◽  
Kang Quan Qiao ◽  
Yi Shun Cui
Keyword(s):  
Weight Loss ◽  
Electron Microscope ◽  
Carbon Steel ◽  
Corrosion Inhibition ◽  
Potentiodynamic Polarization ◽  
Polarization Curves ◽  
Sodium Hexametaphosphate ◽  
Anodic Process ◽  
Polarization Measurements ◽  
Potentiodynamic Polarization Curves

The influence of sodium hexametaPhosphate on the corrosion of carbon steel in 0.5 mol•L-1 KCl solution at 25 °C was investigated using weight loss measurements, potentiodynamic polarization curves and Scan electron microscope (SEM). The obtained results show that sodium hexametaPhosphate is an excellent inhibitor and the inhibition efficiencies exceed 87 %. The polarization measurements reveal that sodium hexametaPhosphate is an inhibitor mainly controlled by anodic process.

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