Study on the Effects of Realkalization Rehabilitation Method Auxiliary Alcamines Inhibitors in Simulative Experiment

2011 ◽  
Vol 243-249 ◽  
pp. 5562-5566
Author(s):  
Jin Liang Lu ◽  
Jun Xi Zhang ◽  
Jun Jiang ◽  
Kun Wang ◽  
Wen Jun Qu
Keyword(s):  
Relaxation Time ◽  
Impedance Spectroscopy ◽  
Current Density ◽  
Corrosion Current Density ◽  
Sodium Carbonate Solution ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Mixed Solution ◽  
Repair Technique ◽  
Electrochemical Parameters

In this paper, the feasibility of inhibitor auxiliary re-alkalization was investigated. The effect of realkalization auxiliary inhibitor repair technique was studied by simulative experiment. It studied the changes of electrochemical parameters of the natural carbonated reinforced concrete during the electrochemical realkalization in 1mol/L Na2CO3 solution and the mixed solution of 1mol/L Na2CO3 and 1 mol/L DMEA , as well as the impedance spectroscopy and polarization curves in the process of relaxation. The results showed that: there appears to be no effect of DMEA on the corrosion potential and the impedance of the steel in the process of realkalization. That was, the performance was the same as that in the sodium carbonate solution except corrosion current of rebar with DMEA which showed much lower. But of the samples which the DMEA existed in the electrolyte was significantly shorter at the same relaxation time after realkalization. At the same relaxation time the corrosion potential was more positive and the corrosion current density was smaller. It improved significantly the effect of realkalization.

Electrochemical Characteristics of Al-Based Coating on Magnesium Alloy Fabricated by Supersonic Particles Deposition

2013 ◽  
Vol 756-759 ◽  
pp. 85-88
Author(s):  
Xiao Ming Wang ◽  
Sheng Zhu ◽  
Qing Chang ◽  
Guo Feng Han
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Magnesium Alloy ◽  
Impedance Spectroscopy ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Electrochemical Characteristics ◽  
Order Of Magnitude

Al-based coating on ZM5 magnesium alloy was prepared by Supersonic Particles Deposition (SPD). Electrochemical working station was utilized to test polarization curve, corrosion potential and electrochemical impedance spectroscopy etc. The results indicted that corrosion potential of Al-Si coating was about-767.6mV, much higher than that of ZM5 Mg-substrate; And corrosion current density of the coating sample decreased three order of magnitude than that of the uncoated. Compared to Mg-substrate, the radius of capacitive impedance arc of the coating enlarged and impedance modulus improved two order of magnitude.

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.

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.

Electrochemical Characteristics of Lanthanum Hexaboride in the Environments Containing S2-

2010 ◽  
Vol 663-665 ◽  
pp. 473-476
Author(s):  
Shu Qi Zheng ◽  
Chang Feng Chen ◽  
Rui Jing Jiang ◽  
Dan Ni Wang
Keyword(s):  
Partial Pressure ◽  
Corrosion Behavior ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Lanthanum Hexaboride ◽  
Electrochemical Characteristics

In the environment with H2S/CO2 or Na2S, the corrosion behavior of Lanthanum hexaboride (LaB6) was investigated by electrochemistry methods. The results indicated that the corrosion potential (Ecorr) and Rf of LaB6 increased as the partial pressure of H2S increased, while the corrosion current density (Icorr) decreased. In the environment containing Na2S, as the content of Na2S increased, the corrosion potential (Ecorr) and Rf of LaB6 decreased, while the corrosion current density (Icorr) increased. Thus, the addition of H2S into the environment with H2S/CO2 would inhibit the corrosion of LaB6; while in the environment containing Na2S, the increasing of the content of Na2S would accelerate the corrosion of LaB6.

scholarly journals Influence of Seawater Salinity on Corrosion of Austenitic Steel

2019 ◽  
Vol 26 (3) ◽  
pp. 219-225
Author(s):  
Robert Starosta
Keyword(s):  
Sodium Chloride ◽  
Corrosion Rate ◽  
Austenitic Steel ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Saturated Calomel Electrode ◽  
Corrosion Current ◽  
Seawater Salinity ◽  
Corrosion Susceptibility

Abstract Due to the paramagnetic properties and the ability to passivation, for the production of hulls of some vessels (mainly warships), corrosion-resistant (stainless) steels with austenitic structure are used. This article describes the influence of seawater salinity on selected corrosion properties of high-alloy steel X5CrNi 18-10 (304). The average salinity of the seas is taken as 3.5% content of sodium chloride. Corrosion rate of the tested material was evaluated in an aqueous solution of sodium chloride was evaluated. The NaCl concentration in corrosive solutions was 0.7%, 1.4%, 2.1%, 2.8%, 3.5%, 4.2%. Corrosion tests were performed using the potentiodynamic method. The range of electrochemical potential changes was Ecorr ±150 mV. Corrosion rate was assessed on the basis of corrosion current density measurements. Corrosion potential values against the saturated calomel electrode were also determined. Based on the obtained measurement results and non-parametric significance tests carried out, a significant influence of seawater salinity on the value of corrosion current density and corrosion potential was found. The highest value of corrosion current density (jcorr), and thus the highest corrosion rate, was recorded for 3.5% NaCl solution. In the concentration range from 0.7 to 3.5% NaCl in solution, the corrosion rate of austenitic steel increases. A further increase in salinity of electrolyte results in the inhibition of corrosion rate of steel. There is almost a full negative, linear correlation between the proportion of sodium chloride in the corrosive solution and the value of corrosion potential. Along with the rise in the salinity of seawater, increase the electrochemical activity, and thus the corrosion susceptibility, thus the corrosion susceptibility, of the austenitic steel X5CrNi 18-10 was observed.

Corrosion behavior of X80 steel under disbond coating interfered with AC

2019 ◽  
Vol 66 (6) ◽  
pp. 704-718
Author(s):  
Qingmiao Ding ◽  
Zili Li ◽  
Tao Shen ◽  
Gan Cui
Keyword(s):  
Corrosion Behavior ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
The Self ◽  
Stray Current ◽  
Content Type ◽  
X80 Steel ◽  
Protection Potential

Purpose This paper aims to research the corrosion behavior of the metal under the disbonded coatings interfered with AC through electrochemical method. Design/methodology/approach The corrosion behavior of the metal under disbond coating interfered with alternate stray current (AC) was studied by electrochemical methods using the rectangular coating disbonded simulator. The obtained data from electrode potential test, electrochemical impedance spectroscopy (EIS) and polarization curves in simulated soil solution indicated that under the natural corrosion condition, the self-corrosion potential and the corrosion current density of the metal at different depths under disbond coating had obviously changed if there was AC interference. Findings The self-corrosion potential of the metal at the same depths under disbond coating shifted negatively with the rising of the AC voltage. Under the condition of cathode polarization, there was still obvious potential gradient with the extension of the deep peeling of the coating gap, and the corrosion current density of the test points was minimum, and the protection effect was best when the cathode protection potential was −1.0 V. When the metal was applied with over-protection, the corrosion rate of the metal increased as AC stray current flowing through it increased. Originality/value This paper used the rectangular aperture device to study the corrosion behavior of X80 steel under the disbonded coatings through electrochemical methods when the AC stray current interference voltage was 0V, 1V, 5V or 10V and the protection potential was 0V, −0.9V, −1.0V, −1.2V or −1.3V, respectively. There is great significance to the safe operation and long-term service of pipeline steel in soil environment.

scholarly journals Experimental Study on the Influence of Sulfate Reducing Bacteria on the Metallic Corrosion Behavior under Disbonded Coating

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Qingmiao Ding ◽  
Liping Fang ◽  
Yanyu Cui ◽  
Yujun Wang
Keyword(s):  
Corrosion Behavior ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Test Point ◽  
Sulfate Reducing ◽  
Metallic Corrosion ◽  
Reducing Bacteria ◽  
Disbonded Coating

A rectangle disbonded coating simulation device was used to research the effect of sulfate reducing bacteria (SRB) on the metallic corrosion behavior under disbonded coating by the electrochemical method. The results showed that the metal self-corrosion potential at the same test point had little change in the initial experiment stage, whether the solution was without or with SRB. The potential amplitude in the solution with SRB was larger than that without SRB in the later corrosion period. The corrosion current density of the metal at the same test point increased gradually over time in the solution with or without SRB, and SRB could accelerate the corrosion of the metal in the disbonded crevice. The metal self-corrosion potential in the crevice had little change in the SRB solution environment after adding the fungicide, but the corrosion current density decreased significantly. That meant the growth and reproduction of SRB were inhibited after adding the fungicide, so the metal corrosion rate slowed down. Among the three kinds of solution environment, increasing the coating disbonded thickness could accelerate the corrosion of the metal in the crevice, and it was the largest in the solution with SRB.

Effects of CeO2 on Microstructure and Corrosion Performance of the Coatings Prepared by Pulse Micro Arc Oxidation on AZ31B Mg Alloy

2020 ◽  
Vol 20 (8) ◽  
pp. 4778-4786
Author(s):  
Lilu Qin ◽  
Jiamu Huang ◽  
Longlong Hao ◽  
Jun Su ◽  
Niu Ma ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Salt Spray ◽  
Electrochemical Measurement ◽  
Corrosion Current ◽  
Corrosion Performance ◽  
Micro Arc Oxidation ◽  
Micro Morphology

To improve corrosion performance of coatings on AZ31B magnesium alloy, the nano-CeO2 additives were included in Na2SiO3 based electrolyte during process of pulse micro arc oxidation (MAO). The MAO-CeO2 coating was successfully prepared to characterize its structure, micro morphology and composition. The XRD results indicated that MAO-CeO2 coatings were consisted of Mg2SiO4, MgSiO3, MgF2 and CeO2. The intensity of CeO2 peaks increases with increasing nano-CeO2 particles in electrolyte. The number of cracks on MAO-CeO2 coatings exhibited a V-shaped trend with increase in nano-CeO2 content. Meanwhile, the influence of nano-CeO2 on corrosion behavior of MAO-CeO2 coatings is investigated by salt spray test and electrochemical measurement. The corrosion current density of coatings presented same trend and corrosion potential is further studied. The MAO-CeO2 coatings formed in electrolyte with 10 g/L nano-CeO2 showed best corrosion performance which has the lowest corrosion current density of 0.58 nA/cm2 and the highest corrosion potential of - 1269 mVSCE.

scholarly journals Galvanic Corrosion of SA106 Gr.B Coupled with Magnetite in Alkaline Solution at Various Temperatures

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 628
Author(s):  
Soon-Hyeok Jeon ◽  
Geun Song ◽  
Sang Kim ◽  
Do Hur
Keyword(s):  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Galvanic Corrosion ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Area Ratio ◽  
Manganese Steel ◽  
Effect Of Temperature ◽  
Reductive Dissolution

The effect of temperature on the galvanic corrosion behavior of SA106 Gr.B carbon-manganese steel was studied in an alkaline aqueous solution at various temperatures (30, 60, and 90 °C) via electrochemical corrosion tests. At all temperatures studied, carbon-manganese steel acted as the anode of the galvanic cell composed of carbon-manganese steel and magnetite because the corrosion potential of carbon-manganese steel was significantly lower than that of magnetite. The corrosion current density of carbon-manganese steel significantly increased due to the galvanic effect irrespective of temperature used in this study. With the increase in temperature, the extent of the galvanic effect on the corrosion current density of carbon-manganese steel and reductive dissolution of magnetite gradually increased. When the area ratio of magnetite to carbon-manganese steel increased, the corrosion rate of the carbon-manganese steel in contact with magnetite further increased.

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.

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