scholarly journals Effect of Chloride Ions Concentrations to Breakdown the Passive Film on Rebar Surface Exposed to L-Arginine Containing Pore Solution

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5693
Author(s):  
Jitendra Kumar Singh ◽  
Soumen Mandal ◽  
Han-Seung Lee ◽  
Hyun-Min Yang
Keyword(s):  
Passive Film ◽  
Pore Solution ◽  
Charge Transfer Resistance ◽  
Chloride Ions ◽  
Passive Films ◽  
The Other ◽  
Transfer Resistance ◽  
Steel Rebar ◽  
Solution Interface ◽  
Corrosion Reaction

In the present study, 0.115 M L-arginine (LA) has been used as an eco-friendly inhibitor in simulated concrete pore solutions (SP-0) in order to form passive films on a steel rebar–solution interface until 144 h. Hence, 0.51 (SP-1) and 0.85 M NaCl (SP-2) were added in LA containing SP-0 solution to breakdown the passive film and to initiate corrosion reactions. The electrochemical results show that the charge transfer resistance (Rct) of steel rebar exposed to SP-1 and SP-2 solutions increased with respect to immersion periods. The sample exposed to the SP-2 solution initiated the corrosion reaction at the steel rebar–solution interface after 24 h of NaCl addition and formed pits; on the other hand, the sample without NaCl added, i.e., SP-0, showed agglomeration and dense morphology of corrosion products.

scholarly journals Protection of Carbon Steel Rebars by Epoxy Coating with Smart Environmentally Friendly Microcapsules

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 113
Author(s):  
Jacob Ress ◽  
Ulises Martin ◽  
Juan Bosch ◽  
David M. Bastidas
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Corrosion Protection ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Pore Solution ◽  
Control Sample ◽  
Chloride Ions ◽  
Epoxy Coating ◽  
Transfer Resistance

The protection of mild steel by modified epoxy coating containing colophony microencapsulated corrosion inhibitors was investigated in this study. The corrosion behavior of these epoxy coatings containing colophony microcapsules was studied by electrochemical analysis using cyclic potentiodynamic polarization and electrochemical impedance spectroscopy. The microcapsule coating showed decreased corrosion current densities of 2.75 × 10−8 and 3.21 × 10−8 A/cm2 along with corrosion potential values of 0.349 and 0.392 VSCE for simulated concrete pore solution and deionized water with 3.5 wt.% NaCl, respectively, indicating improved corrosion protection in both alkaline and neutral pH. Electrochemical impedance spectroscopy analysis also showed charge transfer resistance values over one order of magnitude higher than the control sample, corroborating the electrochemical corrosion potential and current density testing results. Overall, the use of colophony microcapsules showed improved corrosion protection in simulated concrete pore solution and DI water solutions containing chloride ions.

Experimental Study on the Interaction Effect of Sulfate Ions and Chloride Ions on Reinforcement Corrosion in Marine Environment

2017 ◽  
Author(s):  
Yi Huang ◽  
Yunze Xu ◽  
Xiaona Wang ◽  
Shide Song ◽  
Lujia Yang
Keyword(s):  
Passive Film ◽  
Pore Solution ◽  
Construction Materials ◽  
Chloride Ions ◽  
Localized Corrosion ◽  
Test Results ◽  
Reinforcement Corrosion ◽  
Marine Structures ◽  
Sulfate Ions ◽  
Corrosion Risk

Reinforced concrete is one of the most widely used construction materials for marine structures. Due to the abundance of the aggressive ions such as chloride ions and sulfate ions in the seawater, the reinforcement exposed to the marine and costal environment are exposed to a high corrosion risk. Localized corrosion will occur once the passive film on the rebar is damaged. In this work, the corrosion behavior of the steel in the simulated pore solution containing with both sulfate ions and chloride ions are studied by using cyclic potentialdynamic polarization methods and the corrosion morphologies observed using scanning electron microscope (SEM). The test results show that the initial rebar corrosion is caused by the absorption of the chloride ions in the passive film. The sulfate ions nearly had no effect on the corrosion of the rebar in pore solution and it can further mitigate the pitting corrosion in chloride containing pore solution.

Corrosion Behavior of 6000 Series Aluminum Alloys Produced by Conventional and Powder Extruded Process through Electrochemical Impedance Method

2010 ◽  
Vol 654-656 ◽  
pp. 1964-1967
Author(s):  
Satoshi Sunada ◽  
Norio Nunomura ◽  
Kazuhiko Majima
Keyword(s):  
Aluminum Alloys ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
The Other ◽  
Impedance Method ◽  
Ingot Metallurgy ◽  
Transfer Resistance ◽  
Maximum Charge ◽  
Cathodic Region

In this study, the electrochemical measurements such as the potentiodynamic polarization and the electrochemical impedance spectroscopy (EIS) tests were carried out in order to clarify the corrosion behavior of the aluminum alloys fabricated by powder extruded (P/E) process compared with those by ingot metallurgy (I/M) process, using 6000 system aluminum alloys. Two kinds of aluminum specimens; one is fabricated by the conventional I/M specimen and the other is fabricated by the P/E process, were used for the electrochemical experiment in the sulfuric acid solution with 0.5 kmol/m3 concentration. Both of I/M and P/E specimens showed the linear relationship between the electrochemical potential (E) and the common logarithm of current density (icorr) in the cathodic region where Tafel law was recognized irrespective of stirring of the test solution though the icorr was slightly increased by stirring for both specimens. On the other hand, in the anodic region, both of the two specimens indicated the almost the same icorr irrespective of stirring. These experimental results interpret that the corrosion is controlled by the chemical reaction. The EIS test indicated that the maximum charge transfer resistance (Rct) was observed at -0.55 V which is 0.11 V higher potential than the corrosion potential (Ecorr) for both of the two specimens.

Study of the semi-conductive behavior of the passive film on carbon steel in simulated concrete pore solution under stress

2015 ◽  
Vol 62 (6) ◽  
pp. 363-370 ◽  
Author(s):  
Yujie Zhang ◽  
Amir Poursaee
Keyword(s):  
Passive Film ◽  
Design Methodology ◽  
Pore Solution ◽  
Passive Layer ◽  
Chloride Ions ◽  
Content Type ◽  
Ring Model ◽  
Different Types ◽  
Different Levels ◽  
Chloride Contaminated

Purpose – This paper aims to clarify the semi-conductive behavior of the passive layer formed in concrete environment without and with presence of chloride ions under different loading conditions. Passivation and depassivation of steel play an essential role in the subsequent stages of the corrosion process. Due to the nature of passive films on metals, they show electrochemical properties of a semi-conductor. Design/methodology/approach – A C-ring model was proposed in this experiment to induce stress on the specimens. Specimens under different levels of compressive and tensile loadings were exposed to chloride-free and chloride-contaminated solutions and their semi-conductive behavior was investigated using Mott–Schottky technique. Findings – Irrespective of the type and magnitude of the applied load, the passive film on rebars in simulated concrete pore solution is a highly disordered n-type semi-conductor. In all specimens, the presence of chloride ions decreases the slope of the Mott-Schottky plots, the donor density and the space charge layer thickness, which leads to a thinner passive film. Results indicate that steel specimens immersed in chloride-free pore solution under tensile loadings passivate more rapidly compared to those under compressive loadings. However, the situation in chloride-contaminated solution is different, and steel under tensile stress exhibits more corrosion than steel under compressive stress or under no load. Originality/value – Reinforced concrete structures inevitably experience variable mechanical loads, and continuous degradation from aggressive environments. Therefore, it is imperative to study the synergic impact of different types of mechanical loadings and exposure to chloride ions on this process. This paper fulfils this need.

scholarly journals Effect of the Thermomechanical Treatment on the Corrosion of UNSM Processed Inconel 718: An Electrochemical Study

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1488
Author(s):  
Ulises Martin ◽  
Jacob Ress ◽  
David M. Bastidas
Keyword(s):  
Charge Transfer ◽  
Grain Refinement ◽  
Passive Film ◽  
Inconel 718 ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Boundary Density ◽  
Δ Phase ◽  
Corrosion Susceptibility ◽  
Refinement Effect

In this work, the influence of thermal (TT), mechanical, and thermomechanical (TMT) treatments using the ultrasonic nanocrystal surface modification (UNSM) on the corrosion protection properties of Inconel 718 was studied, correlating the changes in the electrochemical properties with the promoted microstructure. The UNSM treatment had a grain refinement effect on the top surface, reducing the grain size from 11.5 to 7.4 µm for the first 10 µm in depth. The high grain boundary density, due to the grain refinement, enabled a faster growth of the passive film. The impedance showed a decrease in the charge transfer resistance by three orders of magnitude, from 106 to 103 Ω cm2 for as-received to 1000 °C, as the TT temperature crossed the solvus of the γ′/γ″ and approached the solvus of the δ-phase. The UNSM treatment lowered the pitting corrosion susceptibility, increasing the charge transfer resistance and decreasing the effective capacitance of the double layer, leading to the thickest passive film with 6.8 nm.

scholarly journals Electrochemical, Thermodynamic, Surface, and Spectroscopic Study in Inhibition of Iron Corrosion with Turmeric Root Extract (TRE)

2020 ◽  
Author(s):  
Khuloud Almzarzie ◽  
Ayman Almassri ◽  
Ahmad Falah ◽  
Hassan Kellawi
Keyword(s):  
Charge Transfer ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Charge Transfer Resistance ◽  
Root Extract ◽  
Iron Corrosion ◽  
Transfer Resistance ◽  
Corrosion Reaction ◽  
Capacitive Loop

Turmeric root extract was tested as corrosion inhibitor for iron in 0.5 M HCl, using potentiodynamic polarization and electrochemical impedance spectroscopy, scanning electron microscope, and energy dispersive X-ray analysis. The inhibition efficiency increases as the time of immersion rises but decreases with temperature rise. The Nyquist plots showed that the charge transfer resistance increases and the double-layer capacitance decreases as the time of immersion increases. Tafel results show that both corrosion current and corrosion speed are reduced with time of immersion. All impedance spectra of EIS tests exhibit one capacitive loop, which indicates that the corrosion reaction is controlled by charge transfer process. Inhibition efficiency increases with the concentration of the inhibitor reaching its maximum value, 88.90%, at 8 g/100 mL. Thermodynamic parameters, Ea, ∆H*, and ∆S*, were estimated, and the mechanism of corrosion and inhibition was discussed. The adsorption of turmeric root extract followed Langmuir adsorption isotherm.

scholarly journals Galvanic Corrosion Study between Tensile-Stressed and Non-Stressed Carbon Steels in Simulated Concrete Pore Solution

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 98
Author(s):  
Zheng Dong ◽  
Chuanqing Fu ◽  
Amir Poursaee
Keyword(s):  
Charge Transfer ◽  
Tensile Stress ◽  
Electrochemical Impedance ◽  
Pore Solution ◽  
Charge Transfer Resistance ◽  
Open Circuit ◽  
Carbon Steels ◽  
Cyclic Polarization ◽  
Transfer Resistance ◽  
Low Frequencies

The present study investigated the galvanic effect between tensile-stressed and non-stressed carbon steels, in addition to the influence of the tensile stress on the passivation and corrosion behavior of steel in a simulated concrete pore solution. Three different levels of tensile stress, ranging from elastic to plastic stress on the surface, were applied by adjusting the displacement of C-shape carbon steel rings. Different electrochemical measurements including the open circuit potential (OCP), the electrochemical impedance spectroscopy (EIS), the zero-resistance ammetry (ZRA), and the cyclic polarization were performed. Based on the results of EIS, the tensile stress degraded the resistance of the oxide film in moderate frequencies while enhancing the charge transfer resistance in low frequencies during passivation. As corrosion propagated, the stressed steel yielded a similar charge transfer resistance to or an even lower charge transfer resistance than the non-stressed steel, especially in the case of plastic tensile stress. The galvanic effect between the tensile-stressed and non-stressed steels increased the chloride threshold value of the tensile-stressed steel, although the susceptibility to pitting corrosion was exhibited after being corroded.

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