Technical Note:Three-Point Method for Evaluating Corrosion Current and Tafel Slopes from a Single Polarization Curve

CORROSION ◽  
1983 ◽  
Vol 39 (1) ◽  
pp. 33-35 ◽  
Author(s):  
S. Barnartt ◽  
M. Donaldson
Keyword(s):  
Polarization Curve ◽  
Corrosion Current ◽  
Point Method ◽  
Tafel Slopes ◽  
Single Polarization

Some Errors in Linear Polarization Measurements and Their Correction

CORROSION ◽  
1974 ◽  
Vol 30 (3) ◽  
pp. 92-96 ◽  
Author(s):  
FLORIAN MANSFELD
Keyword(s):  
Polarization Curve ◽  
Linear Polarization ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Potential Curve ◽  
Polarization Measurements ◽  
Tafel Slopes ◽  
The Relationship ◽  
Current Potential

Abstract The errors due to the use of the approximation Icorr′ = B′ΔI, where B′ depends on anodic and cathodic Tafel slopes, in commercial corrosion current meters is shown to be due to the nonlinearity of the current-potential curve in the vicinity of the corrosion potential. These errors are calculated for various combinations of Tafel slopes. It is proposed to use the relationship Icorr = κΔI, where κ depends on Tafel slopes, sign, and magnitude of polarization. The values of κ are tabulated for various combinations of Tafel slopes and polarization of +10 and −10 mV. The proposed procedure leads to correct values of corrosion currents independent of the degree of nonlinearity of the polarization curve.

Evaluation of Corrosion Rates from Polarization Measurements

CORROSION ◽  
1975 ◽  
Vol 31 (5) ◽  
pp. 173-177 ◽  
Author(s):  
RODNEY L. LeROY
Keyword(s):  
Polarization Curve ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Powerful Method ◽  
Polarization Data ◽  
Polarization Measurements ◽  
Corrosion Rates ◽  
Tafel Slopes ◽  
Tafel Constants

Abstract Polarization measurements within 5 to 20 mV of the corrosion potential offer a powerful method for determining corrosion rates. In this paper, known methods for evaluating the corrosion current from polarization data are critically examined. It is noted that calculated currents are generally in error when the anodic and cathodic Tafel slopes are precisely known, due to non-linearity of the polarization curve. A new result is derived, which allows the corrosion current to be calculated without error if the Tafel slopes are known. Diagrams are presented which show the sensitivity of calculated corrosion rates to errors in estimation of the Tafel constants.

scholarly journals Electrochemical Frequency Modulation: New Approach and Revision of Previous Model

2021 ◽  
Author(s):  
Shashi lalvani ◽  
Lei Kerr ◽  
Shamal Lalvani ◽  
Dominic Olaguera-Delogu
Keyword(s):  
Frequency Modulation ◽  
Corrosion Current ◽  
Peak Potential ◽  
New Approach ◽  
Harmonic Currents ◽  
Algebraic Error ◽  
Tafel Slopes ◽  
Incorrect Model ◽  
Original Derivation

Abstract A careful evaluation of the earlier model (1-2) for electrochemical frequency modulation (EFM) involving two sinusoidal applied potentials for the determination of corrosion parameters shows an algebraic error. Although the missing term in the original derivation appears to be insignificant, it is found that errors involved in corrosion current determination, and especially in evaluation of the Tafel slopes can be very significant, which is of consequence because of the rising popularity of this technique. The magnitude of error is found to be a function of the inherent corrosion characteristics (anodic and cathodic Tafel slopes) of the corroding material as well as the applied peak potential of the modulation. A corrected model with detailed steps showing the appropriate math is presented. In addition, using the experimental data available in the literature, the errors involved in estimating the corrosion parameters by the earlier EFM model of Bosch et al (1-2) are evaluated. The corrected corrosion current and the Tafel slopes can be recovered from the incorrect model without the benefit of the harmonic currents, as shown in this paper.The analysis is also presented for the case of only one applied sinusoidal frequency modulation, which offers several advantages over the multiple frequency modulation.

Effect of Nitrite Ions on Polarization Behavior of Steel Immersed in Simulated Concrete Pore Environments

2013 ◽  
Vol 368-370 ◽  
pp. 919-924
Author(s):  
Zhong Lu Cao ◽  
Makoto Hibino ◽  
Hiroki Goda
Keyword(s):  
Polarization Curve ◽  
Current Density ◽  
Linear Polarization ◽  
Anodic Polarization ◽  
Cathodic Polarization ◽  
Corrosion Current ◽  
Anodic Polarization Curve ◽  
Polarization Curves ◽  
Passive State ◽  
Nitrite Concentration

The influence of nitrite concentration on the linear polarization curves of steel, Tafel slope and Stern-Geary constant B have been investigated in three different pH environments simulating the highly alkaline environment, carbonated environment and neutral environment that really existed on the surface of steel in concrete. The results indicate that when the steel is in passive state, the presence of nitrite has little influence on anodic/cathodic polarization curves and Stern-Geary constant B; but when the steel is corroded, the presence of nitrite not only reduces the current density of anodic polarization curve but also decreases the value of Stern-Geary constant B. If this influence is not considered in practical corrosion measurement, the corrosion current will be overestimated.

Electrochemical Research on N-Type and P-Type Semiconductor Pyrite

2015 ◽  
Vol 1130 ◽  
pp. 179-182
Author(s):  
Jia Ning Xu ◽  
Hong Ying Yang
Keyword(s):  
Cyclic Voltammetry ◽  
Dft Calculations ◽  
Polarization Curve ◽  
Oxidation Reaction ◽  
Dft Calculation ◽  
Corrosion Current ◽  
Stable Property ◽  
Tafel Polarization ◽  
Type Semiconductor ◽  
P Type

Studies on cyclic voltammetry, Tafel polarization curve and DFT calculations on N type and P type semiconductor pyrite in or out of bacterial solution were carried out. Cyclic voltammetry showed that the effect of bacterial was not simply in enrich the Fe3+ in the EPS. Tafel polarization curve research showed that bacteria can enhance the oxidation reaction sharply, no matter in the Fe3+ solution and in the bacteria solution, the corrosion current of N type pyrite was much bigger than that of P type pyrite. The DFT calculation shows that containing one Ni or Co atom means a more stable property, containing one As atom meaning a less stable property. However, an energy band around 5eV occurred in N type pyrite (contained Cu or Ni) meaning that N type pyrite is easier to be oxidation than P type pyrite.

Effects of Temperature on Corrosion Behavior of X70 Steel in Halons

2011 ◽  
Vol 311-313 ◽  
pp. 996-1000 ◽  
Author(s):  
Jing Xu ◽  
Jian Wei Yang ◽  
Jian Ping Cao ◽  
Chen Chen
Keyword(s):  
Corrosion Behavior ◽  
Polarization Curve ◽  
Corrosion Test ◽  
Electrochemical Impedance ◽  
Pipeline Steel ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
X70 Pipeline Steel ◽  
Cathode Reaction ◽  
Immersion Corrosion

The corrosion behavior of X70 pipeline steel in 0.5% NaC1 solution in different temperature of 25°C、35°C and 55°C was studied by dynamic potential polarization curve and electrochemical impedance spectroscopy（EIS）method. The corrosion topography of X70 pipeline steel in normal temperature and 30°C was also compared in immersion corrosion test after 25 days. The results show that when the temperature rises, the corrosion current density Icorr increases, the linear polarization resistance reduces, cathode polarization curve right shift, caused corrosion rate increases which primarily by the increasing the transmission of reactant in the cathode reaction. Pitting corrosion developed after 25 days immersion corrosion in 30°C solution which proved the promoter action of temperature to pit corrosion, and which is agreed with the electrochemical corrosion test results.

Study on the Combined Anticorrosion Method of Thermal Spraying and Coating of Carbon Steel in Deposit Water of Storage Tank

2010 ◽  
Vol 139-141 ◽  
pp. 443-446
Author(s):  
Yong Zhang Zhou ◽  
Chun Yan Yang ◽  
Jian Min Zeng ◽  
Xin Ni ◽  
Dong Sheng Chen ◽  
...  
Keyword(s):  
Weight Loss ◽  
Corrosion Resistance ◽  
Polarization Curve ◽  
Aluminum Powder ◽  
Storage Tank ◽  
Thermal Spraying ◽  
Corrosion Current ◽  
Ac Impedance ◽  
Anodic Polarization Curve ◽  
Glass Flake

Storage tank was protected from corrosion with the combined method of thermal spraying and coating, and corrosion resistance of the coating was studied through on-the-spot static weight loss method, potentiodynamic polarization curve and electrochemical AC impedance test. The result showed that the hanging slices with thermal sprayed aluminum powder, glass flake and epoxy resin coating had least weight loss and best corrosion resistance after 10 months of corrosion with on-the-spot weight loss experiment. In the polarization curve experiment, the anodic polarization curve of the hanging slices with thermal sprayed aluminum powder and glass flake had passivation characteristics, strong polarization area shifted left, weak corrosion current and greater polarization resistance. In the AC impedance spectra, hanging slices with thermal sprayed aluminum powder and glass flake had greater capacitive reactance arc and better corrosion resistance.

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