Effect of particle size on the electrochemical corrosion behavior of X70 pipeline steel

2015 ◽  
Vol 46 (11) ◽  
pp. 1077-1087 ◽  
Author(s):  
B. He ◽  
P. J. Han ◽  
C. Lu ◽  
X. H. Bai
Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1342 ◽  
Author(s):  
Peng Sang ◽  
Liang-Yu Chen ◽  
Cuihua Zhao ◽  
Ze-Xin Wang ◽  
Haiyang Wang ◽  
...  

Particle size is a critical consideration for many powder coating-related industries since it significantly influences the properties of the produced materials. However, the effect of particle size on the characteristics of plasma sprayed NiCrBSi coatings is not well understood. This work investigates the microstructures, hardness and electrochemical corrosion behavior of plasma sprayed NiCrBSi coatings synthesized using different-sized powders. All coatings mainly consist of Ni, N3B, CrB, Cr7C3 and Cr3C2 phases. The coatings produced by small particles (50–75 μm) exhibit lower porosity (2.0 ± 0.8%). Such coatings show a higher fraction (15.5 vol.%) of the amorphous phase and lower hardness (700 HV0.5) than the counterparts (8.7 vol.% and 760 HV0.5, respectively) produced by large particles (75–100 μm) with higher porosity (3.0 ± 1.6%). Meanwhile, the coatings produced from smaller particles possess a larger number of non-bonded boundaries, leading to the easier penetration of corrosive medium, as well as a higher corrosion current density (0.254 ± 0.062 μA/cm2) and a lower charge transfer resistance (0.37 ± 0.07 MΩ cm2). These distinctions are attributed to particle size-induced different melting degrees and stackings of in-flight particles during deposition.


2021 ◽  
Vol 1019 ◽  
pp. 145-156
Author(s):  
Swapna Dey ◽  
Seetharaman Sivaprasad ◽  
Nityananda Das ◽  
Indranil Chattoraj

The pipeline steels which are used for transportation of natural gas and crude oil suffer from hydrogen damage at their internal as well as external surfaces. The internal surfaces of pipelines are generally affected due to hydrogen induced cracking and the external surfaces due to the soil environmental conditions which cause stress corrosion cracking. In the present investigation, the electrochemical corrosion behavior of X70 pipeline steel was studied in sour environment and near neutral soil environment. To assess the mechanism of hydrogen damage in steel, electrochemical hydrogen charging and permeation techniques were used to characterize the hydrogen distribution, trapping and its diffusion in X70 pipeline steel. It has been found that corrosion behavior of pipeline steel in the sour environment is higher than the near neutral soil solution. From the hydrogen permeation study it is established that the hydrogen permeation rate increases with the square root of the charging current density, and the increase of hydrogen flux is directly proportional to the subsurface hydrogen concentration.


2011 ◽  
Vol 311-313 ◽  
pp. 996-1000 ◽  
Author(s):  
Jing Xu ◽  
Jian Wei Yang ◽  
Jian Ping Cao ◽  
Chen Chen

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.


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