scholarly journals Effect of Er-Rich Precipitates on Microstructure and Electrochemical Behavior of the Al–5Zn–0.03In Alloy

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 131
Author(s):  
Muzhi Yu ◽  
Jin Cui ◽  
Zhichao Tang ◽  
Zinan Shen ◽  
Xiaoyang Chen ◽  
...  
Keyword(s):  
Current Efficiency ◽  
Electrochemical Behavior ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Impedance Spectrum ◽  
Corrosion Current ◽  
Element Composition ◽  
The Self ◽  
Dissolution Reaction ◽  
Preferential Dissolution

The effect of Er-rich precipitates on microstructure and electrochemical behavior of the Al–Zn–In anode alloy is investigated. The results showed that with the increase in Er content, the microstructure was refined, the amount of interdendritic precipitates gradually increased, and the morphology changed from discontinuous to continuous network gradually. With the addition of Er element, the self-corrosion potential of the Al–5Zn–0.03In–xEr alloy moved positively, the self-corrosion current density decreased, and the corrosion resistance increased. When the Er content was less than 1 wt.%, the addition of Er improved the dissolution state of the Al–5Zn–0.03In–xEr alloy, and increased the current efficiency of the Al–5Zn–0.03In–xEr alloy. When the Er content was more than 1 wt.%, the current efficiency was reduced. The major precipitate of the alloy was Al3Er. According to the element composition of Al3Er in the Al–Zn–In–Er alloy, the simulated-segregated-phase alloy was melted to explain the effect of Al3Er segregation on the electrochemical behavior of alloys, and the polarization curve and AC impedance spectrum of the simulated-segregated-phase alloy and the Al–Zn–In alloy were measured. The results showed that Al3Er was an anodic segregation phase in the Al–Zn–In–Er alloy, and the preferential dissolution of the segregation phase would occur in the alloy, but the Al3Er phase itself was passivated in the dissolution process, which inhibited the further activation of the dissolution reaction of the Al–Zn–In–Er alloy to a certain extent.

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.

Effect of adding rare-earth cerium on the microstructure and acid rain corrosion resistance of the ADC12 alloy

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
LiJie Zhang ◽  
Hong Yan ◽  
YongCheng Zou ◽  
BaoBiao Yu ◽  
Zhi Hu
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Acid Rain ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
The Self ◽  
Electrochemical Tests ◽  
Immersion Corrosion ◽  
Eutectic Si

Abstract The effect of adding cerium on the microstructure and acid rain corrosion resistance of the AlSi11Cu3 alloy was investigated by means of optical microscopy, scanning electron microscopy, and energy dispersive spectroscopy. The AlSi11Cu3 alloy was doped with varying stoichiometries of cerium to generate AlSi11Cu3-xCe, where x = 0, 0.5, 1.0, and 1.5 wt.%. The results show that the α-Al, eutectic Si, and β-Al5FeSi phases in the AlSi11Cu3-1.0Ce alloy are significantly refined. Electrochemical tests demonstrated an increase in the self-corrosion potential value of the AlSi11Cu3-1.0Ce alloy from –670 mV to –628 mV relative to the untreated alloy. In addition, the AlSi11Cu3-1.0Ce alloy has the lowest corrosion current density (8.4 μA × cm–2). Immersion corrosion testing on the AlSi11Cu3-1.0Ce alloy revealed a corrosion rate of 0.71 mg × cm–2 × d–1, constituting a 72% reduction in the corrosion rate compared to the untreated alloy. These results indicate that the AlSi11Cu3-1.0Ce alloy has a high resistance to acid rain corrosion, which is the result of a refinement of the cathode phases.

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 Microstructure of Al-5Cu-1Li-0.6Mg-0.5Ag-0.5Mn Alloys

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 37
Author(s):  
Wenzheng Chen ◽  
Wenlong Zhang ◽  
Dongyan Ding ◽  
Daihong Xiao
Keyword(s):  
Mechanical Properties ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Aging Treatment ◽  
Corrosion Current ◽  
Homogenization Temperature ◽  
Tafel Polarization ◽  
Al2cu Phase ◽  
Different Temperatures ◽  
Microstructural Optimization

Microstructural optimization of Al-Li alloys plays a key role in the adjustment of mechanical properties as well as corrosion behavior. In this work, Al-5Cu-1Li-0.6Mg-0.5Ag-0.5Mn alloy was homogenized at different temperatures and holding times, followed by aging treatment. The microstructure and composition of the homogenized alloys and aged alloys were investigated. There were Al7Cu4Li phase, Al3Li phase, and Al2CuLi phases in the homogenized alloys. The Al7Cu4Li phase was dissolved with an increase in homogenization temperature and holding time. Al2Cu phase and Al2CuLi phase coarsened during the homogenization process. The alloy homogenized at 515 °C for 20 h was subjected to a two-stage aging treatment. Peak-age alloy, which had gone through age treatment at 120 °C for 4 h and 180 °C for 6 h, was mainly composed of α-Al, Al20Cu2Mn3, Al2CuLi, Al2Cu, and Al3Li phases. Tafel polarization of the peak-age alloys revealed the corrosion potential and corrosion current density to be −779 mV and 2.979 μA/cm2, respectively. The over-age alloy had a more positive corrosion potential of −658 mV but presented a higher corrosion current of 6.929 μA/cm2.

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.

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.

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.

scholarly journals Experimental evaluation of corrosion resistance of the alloys used in the fixed dental prosthesis

2015 ◽  
Vol 61 (2) ◽  
pp. 117-120
Author(s):  
Costin Coman ◽  
◽  
Raluca Monica Comăneanu ◽  
Violeta Hâncu ◽  
Horia Mihail Barbu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Current Density ◽  
Applied Research ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Artificial Saliva ◽  
Corrosion Current ◽  
Open Circuit ◽  
Metal Alloys ◽  
Fixed Dental Prosthesis

Objectives. In this study we evaluated corrosion resistance of three types of metal alloys (two NiCr and one CoCr). Methods. Samples (coded A, B, C) of circular shape, with dimensions 13 x 1.5 mm, sanded and polished, were introduced in Fusayama Meyer artificial saliva at pH 5.2 and 37 ± 0.5°C and tested in terms of corrosion resistance with a potentiostat/galvanostat (model 4000 PARSTAT, Princeton Applied Research). Results. Open circuit potential EOC [mV] ranged between 21.316 and 5.75. Corrosion potential Ecor [mV] was between -73.536 and -395.662, and the corrosion current density icor [A/cm2] was between 1.237 x 10-6 and 905.13 x 10-9. Conclusion. The best corrosion behavior in Fusayama Meyer artificial saliva at pH 5.2 and at a temperature of 37 ± 0.5°C is the alloy A, followed by the alloy C.

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.

Effect of Nano Zirconia on Microstructure and Electrochemical Behavior of Aluminium-Zinc Sacrificial Anodes

2012 ◽  
Vol 519 ◽  
pp. 41-44 ◽  
Author(s):  
Ying Zhang ◽  
Ai Chen ◽  
Cheng Liu ◽  
Hai Rong Wang ◽  
Ze Song Li
Keyword(s):  
Electrochemical Properties ◽  
Current Density ◽  
Electrochemical Behavior ◽  
Corrosion Current Density ◽  
Dendritic Structure ◽  
Corrosion Current ◽  
Sacrificial Anode ◽  
Sacrificial Anodes ◽  
Density Values

In this study, nano ZrO2 powders were incorporated into Al-5 wt% Zn sacrificial anode and the effect of ZrO2 contents (wt% =0.1, 0.2) on microstructures and electrochemical properties were investigated. The results show that the addition of nano ZrO2 was effective on improving metallurgical and electrochemical properties. With the increase of ZrO2 content, the dendritic structure is fined gradually and the corrosion current density values is also increased. The incorporation of ZrO2 also can result in a moderate efficiency value. When the ZrO2 content in the alloy was 0.2 wt%, the optimal microstructure, electrochemical properties and as high as 70% the efficiency value was obtained.

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