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.

Electrochemical Study of Steel Corrosion in Saturated Calcium Hydroxide Solution with Chloride Ions and Sulfate Ions

CORROSION ◽  
10.5006/2634 ◽  
2018 ◽  
Vol 74 (10) ◽  
pp. 1063-1082 ◽  
Author(s):  
Yunze Xu ◽  
Limin He ◽  
Lujia Yang ◽  
Xiaona Wang ◽  
Yi Huang
Keyword(s):  
Calcium Hydroxide ◽  
Passive Film ◽  
Electrochemical Impedance ◽  
Steel Corrosion ◽  
Chloride Ions ◽  
Localized Corrosion ◽  
General Corrosion ◽  
Sulfate Ions ◽  
Hydroxide Solution ◽  
Q235 Carbon Steel

The corrosion of Q235 carbon steel in the saturated calcium hydroxide solution containing chloride ions and sulfate ions are studied using electrochemical methods and wire beam electrode (WBE) sensor. The cyclic potentiodynamic polarization measurements showed that localized corrosion was mainly induced by the adsorption of chloride ions on the passive film. When the passive film is intact, sulfate ions are not corrosive to the passive film and it can inhibit the pitting initiation caused by the chloride ions. However, the WBE test results indicate that once a stable pit has already formed, sulfate ions cannot mitigate the pitting corrosion, and it can further promote the propagation of the major anodic area. Through the electrochemical impedance spectroscopy measurements, it can be found that the addition of sulfate ions in the solution containing chloride ions will not result in the rise of the general corrosion rate.

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.

Corrosion Behavior of Steel Reinforcement in Simulated Concrete Pore Solutions with Various pH and Chloride Contents

2014 ◽  
Vol 629-630 ◽  
pp. 168-172
Author(s):  
Shao Heng Hsieh ◽  
Ran Huang ◽  
Mao Chieh Chi ◽  
Pokuei Liang
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Pore Solution ◽  
Chloride Content ◽  
Chloride Ions ◽  
Test Results ◽  
Weight Loss Measurement ◽  
Half Cell ◽  
Cell Potential ◽  
Significant Factors

Corrosion of rebar in reinforced concrete is a major problem affecting the integrity and loading capacity of the structures. Usually concrete pore solution provides high alkaline environment to protect steel from corrosion. However, the ingress of chloride ions or carbon dioxide would reduce the alkalinity and destroy the stable oxide film which could accelerate the corrosion process of rebar. This study was aimed to evaluate the combined effect of pH and chloride contents on corrosion behavior of rebar using simulated concrete pore solutions. Weight-loss measurement were performed to obtain the corrosion rate. Meanwhile, explore the effect of carbonation and chloride contents to Half-cell potential value on mortar and concrete. Test results show that both pH and chloride content are significant factors influencing the corrosion behavior of rebar. Higher corrosion rate was found in the rebar immersed in the solutions with smaller pH and higher chloride content.

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.

Breakdown of Passive Film on Copper in Bicarbonate Solutions Containing Sulfate Ions

1992 ◽  
Vol 139 (9) ◽  
pp. 2409-2418 ◽  
Author(s):  
I. Milošev ◽  
M. Metikoš‐Huković ◽  
M. Drogowska ◽  
H. Ménard ◽  
L. Brassard
Keyword(s):  
Passive Film ◽  
Sulfate Ions ◽  
Bicarbonate Solutions

Effects of Stress and Plastic Deformation on the Corrosion of Steel

CORROSION ◽  
1970 ◽  
Vol 26 (5) ◽  
pp. 189-199 ◽  
Author(s):  
W. D. FRANCE
Keyword(s):  
Plastic Deformation ◽  
Electrochemical Techniques ◽  
Chloride Ions ◽  
Localized Corrosion ◽  
Dissolution Behavior ◽  
Potential Range ◽  
Chemical Corrosion ◽  
Effects Of Ph ◽  
Current Densities ◽  
The Stability

Abstract The rate and type of corrosion exhibited by mild steel in the annealed, stressed, and plastically deformed state have been investigated. Precise electrochemical techniques provided potential and polarization data to supplement the results of chemical corrosion tests. Experiments were conducted in 0.6M NH4NO3 solutions in which steel exhibits active-passive dissolution behavior as well as localized corrosion. At active potentials, the anodic polarization curves for annealed and deformed specimens were nearly identical, with only slight increases in current densities for the deformed steel. Results at passive potentials demonstrated that increased plastic deformation can markedly decrease the passive potential range, the stability of passivity, and the ability to passivate. At certain passive potentials, the deformed steel exhibited current densities that were 400 times greater than those for annealed steel. The effects of pH, chloride ions, and crevices on the corrosion of deformed steel were examined in detail. The differences between the dissolution behavior of annealed and deformed steel were most distinctive in the approximate pH range of 3 to 6. This work is relevant to the understanding of the initiation of localized corrosion and to anodic protection.

scholarly journals Forming sulfate- and REE-rich fluids in the presence of quartz

Geology ◽  
2019 ◽  
Vol 48 (2) ◽  
pp. 145-148 ◽  
Author(s):  
Hao Cui ◽  
Richen Zhong ◽  
Yuling Xie ◽  
Xueyin Yuan ◽  
Weihua Liu ◽  
...  
Keyword(s):  
Earth Element ◽  
Hydrothermal Systems ◽  
Chloride Ions ◽  
Dissolution Behavior ◽  
Sulfate Ions ◽  
Retrograde Solubility ◽  
Sulfate Salts ◽  
Water Saturated ◽  
Sulfate Melt ◽  
Sulfate Complexes

Abstract The presence of sulfate-rich fluids in natural magmatic hydrothermal systems and some carbonatite-related rare earth element (REE) deposits is paradoxical, because sulfate salts are known for their retrograde solubility, implying that they should be insoluble in high-temperature geofluids. Here, we show that the presence of quartz can significantly change the dissolution behavior of Na2SO4, leading to the formation of extremely sulfate-rich fluids (at least 42.8 wt% Na2SO4) at temperatures >∼330 °C. The elevated Na2SO4 solubility results from prograde dissolution of immiscible sulfate melt, the water-saturated solidus of which decreases from ≥∼450 °C in the binary Na2SO4-H2O system to ∼270 °C in the presence of silica. This implies that sulfate-rich fluids should be common in quartz-saturated crustal environments. Furthermore, we found that the sulfate-rich fluid is a highly effective medium for Nd mobilization. Thermodynamic modeling predicts that sulfate ions are more effective in complexing REE(III) than chloride ions. This reinforces the idea that REEs can be transported as sulfate complexes in sulfate-rich fluids, providing an alternative to the current REE transport paradigm, wherein chloride complexing accounts for REE solubility in ore fluids.

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