Evaluation on the Addition of Inhibitor and Surface Treatment to Corrosion Behavior of the Reinforced Steel Bar Embedded in Mortar Specimen

2017 ◽  
Vol 744 ◽  
pp. 114-120
Author(s):  
Kyung Man Moon ◽  
Sung Yul Lee ◽  
Jae Hyun Jeong ◽  
Myeong Hoon Lee
Keyword(s):  
Current Density ◽  
Test Specimen ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Corrosion Properties ◽  
Mortar Specimen ◽  
Steel Bar ◽  
Steel Bars ◽  
Reinforced Steel ◽  
One Year

In this study, seven types of mortar test specimens were manufactured with parameters, that is, the surface of the reinforced steel bar was treated with hot dip galvanizing (Zn) and the surface of the test specimen was coated with underwater paint, and four types of inhibitors (DAW, MCI, DCI, and Silcon) were added in mortars respectively. And, the seven types of mortar test specimens were immersed in seawater for 4 years. The corrosion properties of the reinforced steel bars embedded in mortar test specimens were investigated using electrochemical methods. The corrosion potentials of the test specimens with painting on the surface of the specimen and Zn coating on the surface of the steel bar exhibited the noblest and lowest values respectively after one year, however, after 4 years, the specimens of underwater painting and of addition of Silcon inhibitor indicated the noblest and lowest values of corrosion potentials respectively. Furthermore, the painting specimen exhibited the smallest values of corrosion probability as welll as of the corrosion current density, while, addition of MCI inhibitor showed the highest values of both corrosion probability and corrosion current density. Moreover, the painting specimen showed the smallest value of neutralization degree among all the specimens, and the largest value of neutralization degree was observed at the specimen of natural condition (no adding of inhibitor, no painting and no Zn coating). As a result, it is considered that the addition of inhibitors, coating with hot dip galvanizing (Zn), and painting on the surface have the effects not only to inhibit the neutralization degree but also to increase the corrosion resistance of the embedded steel bar.

Coating Thickness of Reinforced Concrete Affecting to Cathodic Polarization and Cyclic Voltammogram of Reinforced Steel

2016 ◽  
Vol 723 ◽  
pp. 741-747
Author(s):  
Kyung Man Moon ◽  
Sung Yul Lee ◽  
Jae Hyun Jeong ◽  
Myeong Hoon Lee
Keyword(s):  
Current Density ◽  
Coating Thickness ◽  
Corrosion Current Density ◽  
Cathodic Polarization ◽  
Sea Water ◽  
Corrosion Current ◽  
Corrosion Products ◽  
Cyclic Voltammogram ◽  
Steel Bar ◽  
Reinforced Steel

The reinforced concretes are often exposed to severely corrosive environments such as sea water, contaminated water, acid rain and seashore etc.. Therefore, the reinforced steel bar embedded in the concrete is increasingly corroded in various environments mentioned above, and this corrosion problem is thought to be very important in terms of the safety and economic points of view. In this study, a multiple mortar test specimen(W/C:0.5) with variation of coating thickness was prepared and immerged in flowing seawater for five years. And, the effects of coating thickness affecting to cathodic polarization and cyclic voltammogram were investigated using electrochemical methods. The thinner coating thickness, both invasion and diffusion of dissolved oxygen, water and chloride ion on the surface of reinforced steel bar is more easily compared to the thicker coating thickness. Thus, at the beginning of immersion, the rate of corrosion in the case of the thinner coating thickness is higher than that of the thicker coating thickness. However, it is considered that corrosion products deposited on the surface due to higher corrosion rate played the role as a resistance polarization, and increased the diffusion layer, as a result, decreased the corrosion current density compared to the thicker coating thickness. Consequently, the relationship between corrosion current density and the coating thickness were not well in good agreement with each other due to the corrosion products after being immersed for 5 years. Therefore, in order to more optimum evaluate for corrosion possibility of the reinforced steel embedded in the concrete, not only corrosion potential but also other parameters such as coating thickness, W/C ratio, and other corrosion environment should be investigated in the case of immersed in seawater for long years.

Corrosion of Ni-Al and Ni-Al-Al2O3 Flame Sprayed Coatings of „CastoDyn 8000" System in 0.01 M H2SO4 and 3.5% NaCl Solutions

2011 ◽  
Vol 183 ◽  
pp. 185-192 ◽  
Author(s):  
Robert Starosta
Keyword(s):  
Current Density ◽  
Corrosion Current Density ◽  
Sea Water ◽  
Composite Coatings ◽  
Corrosion Current ◽  
Artificial Seawater ◽  
Flame Spraying ◽  
Al Alloy ◽  
Acidic Environment ◽  
Corrosion Properties

In the paper researches results of corrosion properties of Ni-Al alloy and Ni-Al-Al2O3 composite coatings were presented. Coatings were obtained by flame spraying of "Casto-Dyn 8000" torch. During coatings flame spraying of torch was used a small distance from the substrate. Instead of commonly used spray distance 150 mm, 100 mm was used. The studies in 0.01 M H2SO4 and 3.5% NaCl (artificial seawater) environments were realized. Evaluated coatings are more corrosion resistant in the 3.5% NaCl environment than in the 0.01 M H2SO4. Corrosion current density for alloy coatings in artificial seawater was 20 μA/cm2 and 223 μA/cm2 in an acidic environment. The value of corrosion potential in an environment of 3.5% NaCl is about 200 mV lower than in 0.01 M H2SO4. Composite coatings Ni-Al-Al2O3 were characterized by a lower corrosion current densities and increased resistance than Ni-Al coatings in acidic environment. The presence of alumina in the coating matrix caused increased corrosion current density in sea water environment.

scholarly journals Influence of Seawater Salinity on Corrosion of Hull Structural Steel

2019 ◽  
Vol 26 (2) ◽  
pp. 189-195
Author(s):  
Paweł Zagożdżon ◽  
Robert Starosta
Keyword(s):  
Sodium Chloride ◽  
Structural Steel ◽  
Current Density ◽  
Mass Fraction ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Corrosion Properties ◽  
Corrosion Tests ◽  
Seawater Salinity

Abstract Hulls of ships are often made of steel, which are produced under the supervision of classification societies. Usually, the hull steel of ordinary strength category A is used for the ship's shell (the yield strength is 235 MPa and the impact strength 27 J at 20ºC). Vessels sail in sea areas with various levels of salinity and thus with different corrosiveness. The average salinity of the seas is taken as 3.5% content of sodium chloride. This article presents the results of corrosion tests of S235 JRG1 steel in an aqueous solution in which the mass fraction of sodium chloride was: 0.7%, 1.4%, 2.2%, 2.8%, 3.5% and 4.2%. Corrosion tests were performed using the potentiodynamic method. As parameters characterizing the corrosion properties of the tested steel, the corrosion current density and corrosion potential were assumed. Statistically significant influence of seawater salinity on the corrosion properties of hull structural steel of ordinary strength of category A was found. The highest value of the corrosion current density was observed in the solution containing 3.5% NaCl mass fraction was observed. In seawater with a sodium chloride content in the range of 0.7 to 3.5%, an increase in the value of the corrosion current density was observed, along with the increasing share of NaCl. In seawater with higher salinity, the corrosion rate was reduced. The corrosion potential of S235JRG1 steel decreases with the NaCl content in the corrosive solution. The susceptibility of this material to corrosion in seawater increased.

Corrosion of Ni-Al and Ni-Al-Al2O3 Plasma Sprayed Coatings in 0.01 M H2SO4 and 3.5% NaCl Solutions

2013 ◽  
Vol 199 ◽  
pp. 390-395
Author(s):  
Robert Starosta
Keyword(s):  
Impedance Spectroscopy ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Composite Coatings ◽  
Corrosion Current ◽  
Charge Transfer Resistance ◽  
Al Alloy ◽  
Corrosion Properties ◽  
Transfer Resistance

In the paper researches results of corrosion properties of Ni-Al alloy and Ni-Al-Al2O3 composite coatings were presented. Coatings were obtained by plasma torch. The studies in 0.01 M H2SO4 and 3.5 NaCl environments were realized. Measurements were made following methods: polarization and impedance spectroscopy. Rated coatings are more resistant to the 3.5% NaCl environment than the 0.01 M H2SO4. Corrosion current density for alloy coatings in artificial seawater was 19 μΑ/cm2 and 28 μA/cm2 environment acidic. Impedance spectroscopy studies showed that the alloy and composite coatings are characterized by greater charge transfer resistance in sodium chloride solution than in sulfuric acid solution. The value of corrosion potential in an environment of 3.5% NaCl is about 300 mV lower than 0.01 M H2SO4. Composite coatings Ni-Al-Al2O3 were characterized by a higher corrosion current densities and increased resistance than Ni-Al coatings in 0.01 M H2SO4 solution. It is related to the porosity of composite coatings. It was found little effect of oxide phase participation on corrosion current density and corrosion potential in 3.5% NaCl environment.

Prediction of Steel Bar Corrosion of RC Members Deteriorated by Pre-Existed Chloride and Concrete Carbonation

2015 ◽  
Vol 723 ◽  
pp. 410-418
Author(s):  
Xin Xue ◽  
Wen Xiong ◽  
Hui Chao Wang ◽  
Cong Zhou Shen
Keyword(s):  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Area Ratio ◽  
Concrete Cover ◽  
Total Chloride ◽  
Concrete Carbonation ◽  
Cover Concrete ◽  
Steel Bars ◽  
Combined Action

By simulating solo or combined deterioration action of pre-existed chloride and concrete carbonation, this paper carried out an experimental investigation on the corrosion state of steel bars embedded in concrete with different concrete cover thicknesses and containing different chloride amounts. Comparisons of corrosion current density, corrosion area ratio and corrosion weigh loss of embedded steel bars were made and the effect of combined action was systematically studied. Test results indicated that under the combined action, the corrosion current density measured soon after concrete carbonation test increased with the total chloride amount containing in cover concrete, and the specimens under the combined action exhibited larger value of corrosion current density, corrosion area ratio and mass weight loss than that of the specimens subjected to the solo action. It was further indicated that the mass loss ratio of embedded steel bars at the point of corrosion crack initiation was 1.29% for the specimens with 5mm concrete cover, and the corresponding value of the specimens with 10mm concrete cover was 1.33%.

Corrosion Characteristics of Reinforced Steel Bar Emedded in Mortar Specimen(W/C:0.4) Aged 5 Years in Seawater

2013 ◽  
Vol 753-755 ◽  
pp. 776-783
Author(s):  
Kyung Man Moon ◽  
Jong Pil Won ◽  
Dong Hyun Park ◽  
Myeong Hoon Lee ◽  
Yun Hae Kim
Keyword(s):  
Steel Surface ◽  
Sea Water ◽  
Chloride Ion ◽  
Cyclic Voltammograms ◽  
Corrosion Properties ◽  
Economic Point ◽  
Mortar Specimen ◽  
Steel Bar ◽  
Reinforced Steel ◽  
Cover Thickness

Reinforced concrete structures have been increasingly widely used in numerous industrial fields. These structures are often exposed to severely corrosive environments such as sea water, contaminated water, acid rain, and the seashore. Thus, corrosion problems of the steel bars embedded in concrete are very important from a safety and economic point of view. In this study, the effects of cover thickness on the corrosion properties of reinforced steel bar embedded in mortar specimen were investigated using electrochemical methods such as corrosion potentials, polarization curves, cyclic voltammograms, galvanostat and potentiostat. Corrosion potentials shifted in the noble direction, and the value of AC impedance also exhibited a higher value with decreasing cover thickness, furthermore, polarization resistance also increased with decreasing cover thickness. This is probably that the thinner cover thickness, it is easy for the dissolved oxygen and chloride ion to intrude and diffuse to the steel bar, thereby making it easier to corrode on the steel surface compared to thicker cover thickness, which is resulted in forming the corrosive products on the steel surface. Therefore, it is considered that the corrosive products plays a role to provide nobler value of corrosion potential and higher value of impedance. Consequently, it seems that the corrosion resistance of inner steel bar may depend on mainly not cover thickness but the resistance polarization due to corrosive products in the case of immerged for 5 years in this experiment.

scholarly journals An electrochemical method to investigate the effects of compound composition on gold dissolution in thiosulfate solution

2020 ◽  
Vol 9 (1) ◽  
pp. 496-502 ◽  
Author(s):  
Zhaohui Zhang ◽  
Bailong Liu ◽  
Mei Wu ◽  
Longxin Sun
Keyword(s):  
Dissolution Rate ◽  
Current Density ◽  
Polarization Resistance ◽  
Electrochemical Method ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Gold Dissolution ◽  
Tafel Polarization ◽  
Edta Solution

AbstractThe electrochemical behavior of gold dissolution in the Cu2+–NH3–S2O32−–EDTA solution has been investigated in detail by deriving and analyzing the Tafel polarization curve, as this method is currently widely implemented for the electrode corrosion analysis. The dissolution rate of gold in Cu2+–NH3–S2O32−–EDTA solution was determined based on the Tafel polarization curves, and the effects of various compound compositions in a Cu2+–NH3–S2O32−–EDTA mixture on the corrosion potential and corrosion current density were analyzed. The results showed that the corrosion potential and polarization resistance decreased, whereas the corrosion current density increased for certain concentrations of S2O32−–NH3–Cu2+ and EDTA, indicating that the dissolution rate of gold had changed. The reason for promoting the dissolution of gold is also discussed.

scholarly journals Structure, Corrosion Resistance, Mechanical and Tribological Properties of ZrB2 and Zr-B-N Coatings

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1194
Author(s):  
Philipp Kiryukhantsev-Korneev ◽  
Alina Sytchenko ◽  
Yuriy Kaplanskii ◽  
Alexander Sheveyko ◽  
Stepan Vorotilo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Tribological Properties ◽  
Current Density ◽  
Corrosion Current Density ◽  
Elastic Recovery ◽  
Optical Emission ◽  
Corrosion Current ◽  
Impact Testing ◽  
Total Oxidation ◽  
Mechanical And Tribological Properties

The coatings ZrB2 and Zr-B-N were deposited by magnetron sputtering of ZrB2 target in Ar and Ar–15%N2 atmospheres. The structure and properties of the coatings were investigated via scanning and transmission electron microscopy, energy dispersion analysis, optical profilometry, glowing discharge optical emission spectroscopy and X-ray diffraction analysis. Mechanical and tribological properties of the coatings were investigated using nanoindentation, “pin-on-disc” tribological testing and “ball-on-plate” impact testing. Free corrosion potential and corrosion current density were measured by electrochemical testing in 1N H2SO4 and 3.5%NaCl solutions. The oxidation resistance of the coatings was investigated in the 600–800 °С temperature interval. The coatings deposited in Ar contained 4–11 nm grains of the h-ZrB2 phase along with free boron. Nitrogen-containing coatings consisted of finer crystals (1–4 nm) of h-ZrB2, separated by interlayers of amorphous a-BN. Both types of coatings featured hardness of 22–23 GPa; however, the introduction of nitrogen decreased the coating’s elastic modulus from 342 to 266 GPa and increased the elastic recovery from 62 to 72%, which enhanced the wear resistance of the coatings. N-doped coatings demonstrated a relatively low friction coefficient of 0.4 and a specific wear rate of ~1.3 × 10−6 mm3N−1m−1. Electrochemical investigations revealed that the introduction of nitrogen into the coatings resulted in the decrease of corrosion current density in 3.5% NaCl and 1N H2SO4 solution up to 3.5 and 5 times, correspondingly. The superior corrosion resistance of Zr-В-N coatings was related to the finer grains size and increased volume of the BN phase. The samples ZrB2 and Zr-B-N resisted oxidation at 600 °C. N-free coatings resisted oxidation (up to 800 °С) and the diffusion of metallic elements from the substrate better. In contrast, Zr-B-N coatings experienced total oxidation and formed loose oxide layers, which could be easily removed from the substrate.

scholarly journals Preparation of Ti–Zr-Based Conversion Coating on 5052 Aluminum Alloy, and Its Corrosion Resistance and Antifouling Performance

Coatings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 397 ◽  
Author(s):  
Hehong Zhang ◽  
Xiaofeng Zhang ◽  
Xuhui Zhao ◽  
Yuming Tang ◽  
Yu Zuo
Keyword(s):  
Corrosion Resistance ◽  
Surface Modification ◽  
Aluminum Alloy ◽  
Current Density ◽  
Corrosion Current Density ◽  
Salt Water ◽  
Water Immersion ◽  
Chemical Conversion ◽  
Corrosion Current ◽  
Conversion Coating

A chemical conversion coating on 5052 aluminum alloy was prepared by using K2ZrF6 and K2TiF6 as the main salts, KMnO4 as the oxidant and NaF as the accelerant. The surface morphology, structure and composition were analyzed by SEM, EDS, FT–IR and XPS. The corrosion resistance of the conversion coating was studied by salt water immersion and polarization curve analysis. The influence of fluorosilane (FAS-17) surface modification on its antifouling property was also discussed. The results showed that the prepared conversion coating mainly consisted of AlF3·3H2O, Al2O3, MnO2 and TiO2, and exhibited good corrosion resistance. Its corrosion potential in 3.5 wt % NaCl solution was positively shifted about 590 mV and the corrosion current density was dropped from 1.10 to 0.48 μA cm−2. By sealing treatment in NiF2 solution, its corrosion resistance was further improved yielding a corrosion current density drop of 0.04 μA cm−2. By fluorosilane (FAS-17) surface modification, the conversion coating became hydrophobic due to low-surface-energy groups such as CF2 and CF3, and the contact angle reached 136.8°. Moreover, by FAS-17 modification, the corrosion resistance was enhanced significantly and its corrosion rate decreased by about 25 times.

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