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.

Electrochemical Studies of the Corrosion of Pure Fe, Ni and Cr in Molten (Li,Na,K)F

2014 ◽  
Vol 33 (3) ◽  
pp. 269-276
Author(s):  
Y.X. Xu ◽  
Y.L. Wang ◽  
C.L. Zeng
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Molten Salt Reactor ◽  
Electrochemical Studies ◽  
Warburg Impedance ◽  
Order Of Magnitude ◽  
Molten Fluorides

AbstractThe corrosion of structural materials is a great challenge for the applications of a molten salt reactor using molten fluorides. In this paper, electrochemical behavior of pure Fe, Ni and Cr has been investigated in molten (Li,Na,K)F at 973 K by potentiodynamic polarization and electrochemical impedance spectroscopy. The experimental results indicated that three metals are all in active state at the corrosion potential, with an increase in the corrosion potential by the following order: Cr, Fe, Ni. The free corrosion current density of Ni is more than one order of magnitude lower than that of Fe and Cr. A Warburg impedance was observed in the impedance plots for the corrosion of Cr, but not for Ni and Fe. Ni is the most stable metal, then Fe and Cr, and the corrosion of Cr is controlled by the diffusion of oxidants in the melt.

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.

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 Urea as a complexing agent for selective removal of Ta and Cu in sodium carbonate based alumina CMP slurry

2021 ◽  
pp. 49-49
Author(s):  
Arpita Shukla ◽  
Victoria Selvam ◽  
Manivannan Ramachandran
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Sodium Carbonate ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Corrosion Current ◽  
Complexing Agent ◽  
Downward Pressure

This work reports urea as a promising complexing agent in sodium carbonate (Na2CO3) based alumina slurry for chemical mechanical planarization (CMP) of tantalum (Ta) and copper (Cu). Ta and Cu were polished using Na2CO3 (1 wt.%) with alumina (2 wt.%) in the presence and absence of urea. The effect of slurry pH, urea concentration, applied downward pressure and platen rotational speed were deliberated and the outcomes were conveyed. Prior to the addition of urea, Ta removal rate (RR) was observed to enhance with pH from acidic to alkaline having maximum RR at pH 11. However, Cu RR decreases with increasing pH with minimum RR at pH 11. With the addition of urea in the slurry, Cu to Ta removal rate selectivity of nearly 1:1 is encountered at pH 11. The addition of urea boosts the Ta RR and suppresses Cu RR at the same time at 11 pH, as it adsorbs on the metal surface. Potentiodynamic polarization was conducted to determine the corrosion current (Icorr) and the corrosion potential (Ecorr). The electrochemical impedance spectroscopy (EIS) of both the metals was carried out in the proposed formulation and the obtained outcomes were elaborated.

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.

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 ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY CHARACTERIZATION OF ZW3 MAGNESIUM ALLOY COATED BY DCPD USING LASV DEPOSITION TECHNIQUE

2017 ◽  
Vol 23 (2) ◽  
pp. 147 ◽  
Author(s):  
Daniel Kajánek ◽  
Branislav Hadzima ◽  
Filip Pastorek ◽  
Martina Neslušan Jacková
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Magnesium Alloy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Water Solution ◽  
Electrochemical Characteristics ◽  
Phosphate Dihydrate ◽  
Nyquist Plots ◽  
Eis Measurements

<p class="AMSmaintext"><span lang="EN-GB">The contribution deals with the preparation of the dicalcium phosphate-dihydrate (DCPD) coating on ZW3 magnesium alloy surface. The coating was prepared using large amplitude sinusoidal voltammetry (LASV) electrodeposition technique in water solution of </span><span lang="SK">0.1M Ca(NO<sub>3</sub>)<sub>2</sub>.4H<sub>2</sub>O + 0.06M NH<sub>4</sub>HPO<sub>4 </sub>+ 10 ml.dm<sup>-3</sup> of 50 vol.% H<sub>2</sub>O<sub>2</sub>. </span><span lang="EN-GB">The influence of the DCPD coating on electrochemical characteristics was examined using potentiodynamic polarization (PD) tests and electrochemical impedance spectroscopy (EIS) at the temperature <br /> </span><span lang="EN-GB">22 ± 2 °C in 0.1M NaCl. The obtained PD curves were analysed using Tafel extrapolation method and the data obtained by EIS measurements in a form of Nyquist plots were analysed quantitatively by equivalent circuit method. The results showed the increase of corrosion resistance after application of DCPD coating on ZW3 Mg alloy in sodium chloride solution. </span></p>

A Study on the Electroless Ni–P Deposition of AM60B Magnesium Alloy without HF in Bath

2014 ◽  
Vol 633-634 ◽  
pp. 879-882 ◽  
Author(s):  
Jing Dong Qiu ◽  
Su Qiu Jia
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Electroless Nickel ◽  
Corrosion Current ◽  
Dense Structure ◽  
Electroless Ni

Based on the traditional direct electroless nickel methods, chemical baths are improved by removing HF. Examinations have been carried out on the Ni-P deposited on the interlayer for morphology, composition and corrosion-resistance by SEM, EDS, XRD and other instruments. A Ni-P film with fine and dense structure was obtained on the AM60B magnesium alloy. It exhibits lower corrosion current density and more positive corrosion potential than the substrate.

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 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.

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