scholarly journals Effect of Different Operating Conditions on the Corrosion of Carbon Steel in Oxygenated Sodium Sulphate Solution

2013 ◽  
Vol 4 (3) ◽  
pp. 62-89
Author(s):  
Basim O. Hasan ◽  
Sara A. Sadek
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Corrosion Product ◽  
Current Density ◽  
Considerable Increase ◽  
Rotational Velocity ◽  
Sodium Sulphate ◽  
Operating Conditions ◽  
Limiting Current ◽  
Limiting Current Density

 Carbon steel is a major metal used in manufacturing of the equipments used in petroleum industry and it is subject to different operating conditions causing various corrosion attacks. Corrosion of carbon steel in sodium sulphate solution (Na2SO4) under flow conditions was investigated using rotating cylinder electrode (RCE) for a range of rotation velocity (0 – 2000 rpm) and temperatures (32 - 52 oC). The corrosion rate  was determined by using both weight loss method and electrochemical polarization technique (limiting current density). Different salt concentrations were investigated ranged from 0.01 to 0.4 M. The effect of time (or corrosion product formation) and the effect of oxygen concentration through air bubbling in the solution were also investigated and discussed. The results showed that increasing  rotational velocity leads to a considerable increase in the corrosion rate represented by limiting current density. The corrosion rate had unstable trend with salt concentrations and temperature. Generally, the corrosion rate decreased appreciably with time due to the formation of corrosion product layer depending on rotational velocity, temperature, and oxygen concentration. It was found that, air pumping through the salt solution leads to a considerable increase in the limiting current density (iL) depending on rotational velocity, temperature, and time.

scholarly journals PIPELINE CATHODE PROTECTION ANALYSIS FOR IDENTIFICATION OF CORROSION AND STRESS-CORROSION FORMATION

2018 ◽  
pp. 128-139
Author(s):  
V. I. Khizhnyakov ◽  
A. V. Negodin ◽  
V. S. Kalinichenko
Keyword(s):  
Surface Layer ◽  
Corrosion Rate ◽  
Current Density ◽  
Hydrogen Pressure ◽  
Hydrogen Release ◽  
Limiting Current ◽  
Closed Cavity ◽  
Near Surface ◽  
Limiting Current Density ◽  
Cathode Protection

Based on long-term corrosion tests of 17GS steel samples of the pipeline installed in various soils of the taiga-marsh region in the central part of Western Siberia, it is shown that in the absence of cathode protection, the corrosion rate ranges from 0.11 to 0.06 mm per year, i.e. 0.085 mm per year averagely. The residual corrosion rate of samples under the cathode protection ranges from 0.01 to 0.004 mm per year or the 0.007 mm per year averagely, when the air limiting current density exceeds the oxygen limiting current density by a factor of 3-7. A further increase in the current of cathode protection leads to the intensive hydrogen release. The actual measured values of the cathode protection current density at its potentials (with the resistive component) from –1.79 V to 3.5 V exceed the oxygen limiting current density by 30–50 or more times. It is experimentally shown that at a cathode current density  exceeding the density of oxygen limiting current by 54.43 times, the acceleration of hydrogen pressure reaches 0.007 MPa per day in a closed cavity at a 20 mm vacuum pressure. It is shown that the acceleration of hydrogen pressure in micro- and macro-cavities of the near-surface layer of the pipeline is not determinant. The advantageous embrittlement of cathode hydrogen is the reduction of cohesive strength of the near-surface layer of the pipe wall.

scholarly journals Limiting Current Density of Oxygen Reduction under Ultrathin Electrolyte Layers: From the Micrometer Range to Monolayers

2021 ◽  
Vol 8 (4) ◽  
pp. 712-718
Author(s):  
Xiankang Zhong ◽  
Matthias Schulz (née Uebel) ◽  
Chun‐Hung Wu ◽  
Martin Rabe ◽  
Andreas Erbe ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Current Density ◽  
Limiting Current ◽  
Limiting Current Density

scholarly journals Demineralization of Rehydrated Cheese Whey by Electrodialysis. Effects of deashing rates and solid concentration on limiting current density.

1991 ◽  
Vol 17 (5) ◽  
pp. 1006-1011 ◽  
Author(s):  
Yasunobu Hiraoka ◽  
Akira Tomizawa ◽  
Tatsuki Oguchi ◽  
Etsuko Suzuki ◽  
Masanobu Koutake
Keyword(s):  
Current Density ◽  
Cheese Whey ◽  
Limiting Current ◽  
Solid Concentration ◽  
Limiting Current Density

Polarization Characteristics to Wear Ratio of Anti-Fouling Paint

2015 ◽  
Vol 1110 ◽  
pp. 179-184
Author(s):  
Kyung Man Moon ◽  
Dong Hyun Park ◽  
Yun Hae Kim ◽  
Tae Sil Baek
Keyword(s):  
Current Density ◽  
Corrosion Potential ◽  
Wear Test ◽  
Life Time ◽  
Point Of View ◽  
Limiting Current ◽  
Limiting Current Density ◽  
Wear Ratio ◽  
Polarization Characteristics ◽  
Lower Variation

Recently, anti-fouling paints which does not include the poison components such as tin (Sn) free, copper (Cu) free have been increasingly developed in order to decrease the contamination of marine environment. Moreover, the wear ratios of these anti-fouling paints are very important problem to prolong their life time in economical and environmental point of view. In this study, four types of anti-fouling paints as self-polishing type were investigated on the relationship between their polarization characteristics and wear ratios. Relationship between wear ratio and variation ratio of polarization resistance measured in corrosion potential was not well matched with each other. However, there was a good agreement between the wear ratio and variation ratio of diffusion limiting current density, for example, the higher or the lower variation ratio of diffusion limiting current density, wear ratio also increased or decreased respectively. Consequently, it is suggested that we can qualitatively expect the life time and wear degree of anti-fouling paint by only measuring the polarization characteristics before the wear test is practically performed in the field.Keywords: Anti-fouling paint, Self-polishing type, Polarization characteristics, Wear ratio, Diffusion limiting current density, Corrosion Potential

Limiting current density in a crossed-field nanogap

2001 ◽  
Vol 64 (1) ◽  
Author(s):  
L. K. Ang ◽  
T. J. T. Kwan ◽  
Y. Y. Lau
Keyword(s):  
Current Density ◽  
Limiting Current ◽  
Limiting Current Density
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