scholarly journals The Study of Corrosion Behaviors of Carbon Steel Weldments and Their Inhibition in Simulated Pore Solution Using Multi-Electrode Array Technique

2021 ◽  
Vol 11 (18) ◽  
pp. 8278
Author(s):  
Lujia Yang ◽  
Zhenping Ma ◽  
Yufeng Zheng ◽  
Xiaona Wang ◽  
Yi Huang ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Pore Solution ◽  
Galvanic Corrosion ◽  
Electrode Array ◽  
Open Circuit ◽  
Localized Corrosion ◽  
Galvanic Current ◽  
Corrosion Behaviors ◽  
Weld Area ◽  
Multi Electrode Array

A multi-electrode array sensor was developed to study the corrosion behaviors of carbon steel weldments and the effectiveness of the NaNO2 inhibitor in carbonated pore solution. The sensor can simulate a complete weldment, and the measurement results can match well with the coupon immersion test. The galvanic corrosion between the weld area, heat-affected area, and base metal area, as well as the effect of nitrite corrosion inhibitor on the weld area, were observed by measuring the open circuit potential, coupling potential, and galvanic current. The results show that corrosion is likely to happen around the weld metal area and its adjacent heat-affected zone. The intensive galvanic currents can accelerate the localized corrosion, while NaNO2 can inhibit it.

scholarly journals In-Situ Monitoring and Analysis of the Pitting Corrosion of Carbon Steel by Acoustic Emission

2019 ◽  
Vol 9 (4) ◽  
pp. 706 ◽  
Author(s):  
Junlei Tang ◽  
Junyang Li ◽  
Hu Wang ◽  
Yingying Wang ◽  
Geng Chen
Keyword(s):  
Acoustic Emission ◽  
Carbon Steel ◽  
Pitting Corrosion ◽  
Optical Microscope ◽  
Open Circuit ◽  
In Situ Monitoring ◽  
Localized Corrosion ◽  
Uniform Corrosion ◽  
Corrosion Morphology

The acoustic emission (AE) technique was applied to monitor the pitting corrosion of carbon steel in NaHCO3 + NaCl solutions. The open circuit potential (OCP) measurement and corrosion morphology in-situ capturing using an optical microscope were conducted during AE monitoring. The corrosion micromorphology was characterized with a scanning electron microscope (SEM). The propagation behavior and AE features of natural pitting on carbon steel were investigated. After completion of the signal processing, including pre-treatment, shape preserving interpolation, and denoising, for raw AE waveforms, three types of AE signals were classified in the correlation diagrams of the new waveform parameters. Finally, a 2D pattern recognition method was established to calculate the similarity of different continuous AE graphics, which is quite effective to distinguish the localized corrosion from uniform corrosion.

Studies on CUI of Carbon Steel in Simulation Environment Containing Chloride and Sulfur at 80°C

2012 ◽  
Vol 509 ◽  
pp. 166-170
Author(s):  
Jian Qun Tang ◽  
Jian Ming Gong ◽  
Ying Jie Jiang
Keyword(s):  
Carbon Steel ◽  
Metal Surface ◽  
Localized Corrosion ◽  
Experimental Simulation ◽  
Simulation Environment ◽  
Nacl Concentration ◽  
Corrosion Behaviors ◽  
Small Cracks ◽  
Testing Solution ◽  
Corrosion Under Insulation

Corrosion under insulation (CUI) is a localized corrosion occurring at the interface of a metal surface and the insulation on the metal surface. In order to explore the mechanism of CUI, some tests were conducted on 20 # carbon steel under insulation dripping different testing solution at 80°C in an experimental simulation device for CUI. Corrosion behaviors were analyzed by weight loss methods and other methods. The results showed that CUI rate of 20# carbon steel increased with NaCl concentration. The addition of sulfur and the decrease of pH promoted corrosion. The pits and small cracks were found on the corroded metal and the bonding between products and matrix was strong.

scholarly journals Roughness Effect on Corrosion of Gr-Cu -Ni Coated Steel in Saline Water

2021 ◽  
Vol 23 (12) ◽  
pp. 89-101
Author(s):  
A.A. Atia ◽  
◽  
M.M. Sadawy ◽  
A. A. Kandil ◽  
A. A. Atlam ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Saline Water ◽  
Open Circuit ◽  
Surface Finishing ◽  
X Ray Diffraction ◽  
Roughness Effect ◽  
X Ray ◽  
Tafel Polarization ◽  
Corrosion Behaviors ◽  
Effect Of Surface

Effect of surface roughness on corrosion behavior for carbon steel was coated by metallic layers Cu- Ni Reinforced with Gr layers. Surface finishing P320, P600 and P1200 mesh used until a mirror shiny surface before metallic coated with Gr layers at consecrations 0.25, 0.5, 1and 2 g/l of Gr. First, X-ray diffraction), electron microscopy associated for carbon steel & Gr and Microscopic test for coated specimens. The techniques were performed to study the effect of saline water (3.5%) on the corrosion behaviors, Open circuit potential, Tafel polarization and impedance spectroscopy tests. At P320 Equivalent Circuit elements were decreasing but, Corrosion reaction’s Rp was increased at 5 min and 0.25 g/l. And also, coating’s Rpore with Electrolyte’s Ru were increasing at 30 min for 0.5 g/l, and also coating’s Rpore and Electrolyte’s Ru were increased at 20 min for 1 g/l, At P600 ECE’s were decreasing but, corrosion reaction’s Rp was increased at 30 min 1 g/l, and also, coating’s Rpore and Electrolyte’s Ru were increased at 20 min for 1 g/l, and At P1200 ECE’s were decreasing but, Coating’s Ccoat was increased at 5 min 0.25 g/l, and also coating’s Rpore and Electrolyte’s Ru were increased at 0.5g/l, 30 min.

Corrosion study of low carbon steel under simulated geological disposal environments for HLW in China

2020 ◽  
Author(s):  
Junhua Dong
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Dissolved Oxygen ◽  
Open Circuit Potential ◽  
Steel Substrate ◽  
Low Carbon Steel ◽  
Open Circuit ◽  
Localized Corrosion ◽  
Low Carbon ◽  
Simulated Groundwater

<p>In the multi-barrier system of HLW repository, overpack is the first barrier to isolate high-level radioactive nuclides from biosphere, and Low carbon steel has been considered to be a promising candidate material for manufacturing the oberpack due to its good mechanical performance and workability and weldability. However, during thousands of years of geological disposal, the corrosion resistance of low carbon steel and its corrosion evolution behavior are the first element that must be fully understood, because it determines the life cycle of the artificial barrier.</p><p>Conventional studies had suggested that the corrosion of low carbon steel under the deep geological environment was driven by hydrogen evolution reaction (HER) based on that the dissolved oxygen was completely depleted during the long term disposal. However, the residual oxygen content is a critical factor to determine the corrosion mode of cathodic reduction reaction. Thermodynamics data indicated that the initial ferrous corrosion products formed in the deaerated bicarbonate solution can be chemically oxidized into ferric substance by the trace content of dissolved oxygen, and the accumulated FeOOH as a cathodic depolarizer significantly increased the open circuit potential and enhanced the corrosion rate of the low carbon steel. Moreover, chloride and sulfate in the simulated groundwater can reduce the increase of open circuit potential but it still promotes the corrosion of the low carbon steel. As the environments contained aggressive anions and high concentration of dissolved oxygen, low carbon steel was prone to suffer from the localized corrosion and the corrosion rate was obviously increased. By alloying with some contents of Ni and Cu, the corrosion rate of low alloy steel was decreased by an order of magnitude and it was less prone to suffer from the localized corrosion.</p><p>Under the conditions of simulated groundwater with different content of GMZ bentonite，the bentonite colloidal particle layer attached to the surface of low carbon steel showed blocking effect on resisting oxygen diffusion to the steel substrate, which consequently decrease the further oxidation of ferrous to ferric substances and the corrosion rate of low carbon steel. However, the barrier performance of bentonite colloids would be deteriorated due to their coagulation caused by the ferrous ions dissolved from the steel substrate. High content of bentonite was beneficial to maintain and to prolong the stabilization of the barrier system. An equivalent circuit model which correlates with the interfacial structure between electrode substrate and rust and bentonite layer was proposed. The fitting results showed a very good match between the model and experimental data, and the evolution of the results was also in agreement with real changes.</p>

scholarly journals Corrosion Inhibition of the Galvanic Couple Copper-Carbon Steel in Reverse Osmosis Water

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Irene Carrillo ◽  
Benjamín Valdez ◽  
Roumen Zlatev ◽  
Margarita Stoycheva ◽  
Michael Schorr ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Reverse Osmosis ◽  
Corrosion Inhibition ◽  
Heat Exchangers ◽  
Electrochemical Impedance ◽  
Galvanic Corrosion ◽  
Electrochemical Behaviour ◽  
Open Circuit ◽  
X Ray ◽  
Galvanic Couple

The purpose of this paper is to evaluate the electrochemical behaviour of corrosion inhibition of the copper-carbon steel galvanic couple (Cu-CS), exposed to reverse osmosis water (RO) used for rinsing of heat exchangers for heavy duty machinery, during manufacture. Molybdate and nitrite salts were utilized to evaluate the inhibition behaviour under galvanic couple conditions. Cu-CS couple was used as working electrodes to measure open circuit potential (OCP), potentiodynamic polarization (PP), and electrochemical impedance spectroscopy (EIS). The surface conditions were characterized by scanning electron microscopy (SEM) and electron dispersive X-ray spectroscopy (EDS). The most effective concentration ratio between molybdate and nitrite corrosion inhibitors was determined. The morphological study indicated molybdate deposition on the anodic sites of the galvanic couple. The design of molybdate-based corrosion inhibitor developed in the present work should be applied to control galvanic corrosion of the Cu-CS couple during cleaning in the manufacture of heat exchangers.

scholarly journals Galvanic Corrosion between Depleted Uranium and 40Cr Steel

2012 ◽  
Vol 531-532 ◽  
pp. 220-225
Author(s):  
Zhen Pu ◽  
Qing Fu Wang ◽  
Mao Bin Shuai ◽  
Ding Mu Lang
Keyword(s):  
Current Density ◽  
Linear Polarization ◽  
Galvanic Corrosion ◽  
Corrosion Current ◽  
Open Circuit ◽  
Depleted Uranium ◽  
Accelerated Corrosion ◽  
Linear Polarization Resistance ◽  
Corrosion Behaviors ◽  
40Cr Steel

Individual corrosion and galvanic corrosion behaviors of depleted uranium (DU) and 40Cr steel were investigated by electrochemical analyzing technologies in 3.5w.t%NaCl solution, including open circuit potential(OCP) test, linear polarization(LP) test, potentiodynamic polarizaition(PD) test, galvanic corrosion potential and corrosion current density test. The results reveal that the OCP of DU and 40Cr steel are around -790mV and -660mV, respectively. 40Cr has a higher linear polarization resistance than DU in galvanic corrosion. The dynamic processes of galvanic corrosion goes through an conversion in the whole test period. DU acts as anode with an accelerated corrosion rate, while the 40Cr steel behaves as cathode during the process of galvanic corrosion for DU/40Cr couple. The galvanic potential and current density of the DU/40Cr couple are -780mV and 17.5μA/cm-2, respectively.

Effects of Surface Oxide Coating on Corrosion Behavior of Ti-1023/LY12 Galvanic Couple

2013 ◽  
Vol 668 ◽  
pp. 880-884 ◽  
Author(s):  
Jun Xiu Shi ◽  
Jian Hua Liu
Keyword(s):  
Corrosion Behavior ◽  
Galvanic Corrosion ◽  
Oxide Coating ◽  
Optical Microscope ◽  
Open Circuit ◽  
Localized Corrosion ◽  
Corrosion Attack ◽  
Corrosion Properties ◽  
Corrosion Morphology ◽  
Galvanic Couple

Galvanic corrosion behavior of Ti-1023 titanium alloy coupled to LY12 aluminum alloy was investigated in 3.5% NaCl solution. Particular attention was given to the effect of anodized coatings on corrosion behaviors of Ti-1023/LY12 galvanic couple. Galvanic test was conducted on the following couples: Ti-1023/LY12, Ti-1023/anodized LY12 and anodized Ti-1023/anodized LY12, respectively. Corrosion properties including open circuit potential (Eoc) of each material, galvanic corrosion potential (Eg) and galvanic corrosion current (Ig) of the couples were monitored. Corrosion morphology was observed by optical microscope (OM) and corrosion mechanisms were analyzed and discussed. It was showed that anodized coatings significantly decreased Eg and Īg of the couples and provide effective protection of the anode from suffering corrosion attack. Only slight localized corrosion was detected on anodized LY12 alloy in the two anodized couples and the LY12 in anodized Ti-1023/anodized LY12 couple was found to be least susceptible to galvanic corrosion. The LY12 alloy in the bare couple: Ti-1023/LY12, was found to be highly susceptible to galvanic corrosion and suffered severe uniform and localized corrosion attack

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