scholarly journals Electrochemical investigation of cold worked copper in alkaline solution with the presence of potassium ethyl xanthate

2014 ◽  
Vol 68 (3) ◽  
pp. 279-288 ◽  
Author(s):  
Svetlana Ivanov ◽  
Mirjana Rajcic-Vujasinovic ◽  
Jasmina Petrovic ◽  
Vesna Grekulovic ◽  
Srba Mladenovic
Keyword(s):  
Anodic Polarization ◽  
Open Circuit Potential ◽  
Copper Wire ◽  
Cold Drawing ◽  
Open Circuit ◽  
Degree Of Deformation ◽  
Ethyl Xanthate ◽  
Cold Worked ◽  
And Behavior ◽  
Potassium Ethyl Xanthate

This paper presents the investigation results of the electrochemical behavior of copper in 1 M Na2CO3 solution in the presence of potassium ethyl xanthate (KEtX) with different concentrations. Tests were conducted on copper samples obtained without deformation and with deformation of 83, 91 and 99 %. Samples were obtained by cold drawing of wire, which was previously obtained by dip-forming procedure. Corrosion behavior of cold deformed copper wire is characterized by its open circuit potential and behavior during anodic polarization. Experiments were carried out in aqueous solution 1 M Na2CO3 with added various amounts of KEtX between 0.008 g/l and 0.15 g/l. It was experimentally proved that the degree of deformation between 83 and 99 % does not have a large effect on the open circuit potential, as well as on the behavior of copper during anodic polarization in 1 M Na2CO3. Voltammograms show no significant differences between peak heights obtained for different electrodes. The first peak which occurs at potential of around -0.06 V vs. SCE corresponds to the formation of copper oxide Cu2O. The second wide peak is at potential of around 0.15 V vs. SCE and corresponds to the formation of CuO. Addition of potassium ethyl xanthate in alkaline 1 M Na2CO3 solution changes the mechanism of the process in anodic part, which is reflected in the change of shape of voltammograms. In presence of KEtX in concentration between 0.008 g/l and 0.15 g/l on voltammograms a sharp peak appears at potential of about -0.2 V vs. SCE and corresponds to the oxidation of xanthate. Current density, which determines the rate of the process which takes place at the electrode surface, yet in the presence of smallest amounts of KEtX (<0,08 g/l) is higher than in the absence of KEtX. It allows one to conclude that the processes of oxidation of copper accelerate in presence of potassium ethyl xanthate.

scholarly journals The influence of gelatine on the corrosion behaviour of cold worked copper wire in alkaline media

2006 ◽  
Vol 42 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Svetlana Ivanov ◽  
Mirjana Rajcic-Vujasinovic ◽  
Zoran Stevic
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behaviour ◽  
Copper Wire ◽  
Positive Influence ◽  
Open Circuit ◽  
Alkaline Media ◽  
Forming Process ◽  
Deformation Degree ◽  
Cold Worked ◽  
Potentiodynamic Method

Copper wire obtained by dip-forming process was cold worked to the deformation degrees of 83, 87, 91, 95 and 99 %. Electrochemical potentiodynamic method was used to investigate corrosion behavior of these wires in aqueous solutions of Na2CO3 (1 mol/dm3). Open circuit potentials as well as peak potentials are given as a function of deformation degree in Na2CO3 without and with addition of gelatine in concentration between 0.1 and 0.5 g/l. It was found that the addition of gelatine does not change the mechanism of the process, but influences on current density. Small concentrations of gelatine (0.1 g/l or less) have positive influence on the corrosion protection of copper in alkaline solution, but the addition of gelatine in concentration 0.5 g/l causes the increasing of its corrosion rate.

Obtaining and Characterization of Zirconium and Cerium Coatings

2016 ◽  
Vol 869 ◽  
pp. 711-715
Author(s):  
Larissa Oliveira Berbel ◽  
Larissa Aparecida Corrêa Matos ◽  
Paulo Vitor Sochodolak ◽  
Claudia Schlindwein ◽  
Paulo Rogério Pinto Rodrigues ◽  
...  
Keyword(s):  
Metal Surfaces ◽  
Anodic Polarization ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Pechini Method ◽  
Open Circuit ◽  
Good Resistance ◽  
Potentiodynamic Anodic Polarization ◽  
Scanning Electron

Some metals prior to receiving a layer of paint should be submitted to a treatment of metal surface, since they are subjected to corrosion. This work aims the obtaining and characterization of a coating based on ceramics of cerium and / or zirconium for metal surfaces treatment. The ceramics were obtained by immersing the aluminum alloy 3003 and the carbon steel (SAE 1010) in the polymeric resin of citric acid and ethylene glycol according to the Pechini method. The characterization of the samples was performed using the following techniques: scanning electron microscopy (SEM), open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and Potentiodynamic Anodic Polarization (PAP). It was confirmed that the coatings of cerium and / or zirconium presented themselves as promise in the treatment of metal surfaces, because both showed good resistance, protecting the metal from corrosion.

Effect of Phosphorus on the Corrosion Resistance of Nickel Electrocoatings

2015 ◽  
Vol 228 ◽  
pp. 310-316
Author(s):  
B. Łosiewicz ◽  
Magdalena Popczyk ◽  
Magdalena Szklarska ◽  
Patrycja Osak
Keyword(s):  
Corrosion Resistance ◽  
Anodic Polarization ◽  
Open Circuit Potential ◽  
Electrochemical Corrosion ◽  
Amorphous Structure ◽  
Open Circuit ◽  
Alkaline Solutions ◽  
Nickel Coatings ◽  
Effective Manner ◽  
Passivation Potential

The electrodeposited Ni-P coatings are commonly used for their electrocatalytic properties towards hydrogen evolution reaction. However, their corrosion resistance in concentrated alkaline solutions is still less known. In this work, the effect of phosphorus on the resistance of nickel electrodeposits to electrochemical corrosion in 5 M KOH solution, was studied. Open circuit potential and anodic polarization measurements were performed to determine parameters of the corrosion resistance of the crystalline Ni deposit and amorphous Ni-P electrocoating. It was found that alloying of nickel with phosphorus is the effective manner of the improvement of the corrosion resistance of the nickel coatings. The obtained Ni-P electrode material contained 10 wt.% of P and revealed amorphous structure. The increase in the corrosion resistance of the Ni90P10system as compared to that determined for comparable Ni polycrystalline electrode was due to phosphate formation responsible for broad passivation potential in alkaline medium and amorphous structure.

scholarly journals An Electrochemical Study to Evaluate the Effect of Calcium Nitrite Inhibitor to Mitigate the Corrosion of Reinforcement in Sodium Chloride Contaminated Ca(OH)2Solution

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Hwa-Sung Ryu ◽  
Jitendra Kumar Singh ◽  
Han-Seung Lee ◽  
Won-Jun Park
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Sodium Chloride ◽  
Anodic Polarization ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Nacl Solution ◽  
Steel Rebar ◽  
Calcium Nitrite ◽  
Corrosion Of Steel

The effect of calcium nitrite (Ca(NO2)2) was assessed by electrochemical means such as open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic studies in saturated Ca(OH)2solution contaminated with 0.99 and 7.91 g/L NaCl. The preliminary results of OCP showed that the potential is shifted towards positive (noble) side as content of inhibitor increased. The EIS results indicate that Ca(NO2)2works effectively in reduction and initiation of corrosion of steel rebar in NaCl contaminated Ca(OH)2solution. Potentiodynamic studies revealed the pitting tendency of steel rebar exposed in 0.99 g/L NaCl at [Cl−/NO2-] = 1.2 attributed to low conductivity of passive film which causes interference for Cl−ions attack during anodic polarization. The 85.75% efficiency is found in 0.99 g/L at [Cl−/NO2-] = 1.2. The Ca(NO2)2inhibitor transformed the unstable iron oxides/hydroxides into stable and protective oxides/hydroxides due to its strong oxidizing nature. Therefore, this inhibitor is sufficiently and significantly reducing the corrosion of steel rebar at even its low concentration with 0.99 and 7.91 g/L NaCl solution.

On the Corrosion Mechanisms of Al-Cu-Fe Quasicrystals

2000 ◽  
Vol 643 ◽  
Author(s):  
A. Rüdiger ◽  
U. Köster
Keyword(s):  
Anodic Polarization ◽  
Open Circuit Potential ◽  
Selective Dissolution ◽  
Open Circuit ◽  
Al Content ◽  
Small Influence ◽  
Current Densities ◽  
Corrosion Mechanisms ◽  
Nanocrystalline Layer ◽  
Quasicrystalline Structure

AbstractThe mechanisms of dissolution and passivation of bulk polycrystalline icosahedral Al63Cu25Fe12 during electrolytic corrosion in 0.1 N NaOH and 1 N H2SO4 were studied in detail. In 1 N H2SO4 selective dissolution of Al and Fe occurs at the open circuit potential, which leads to a porous layer of recrystallized fcc Cu; after anodic polarization dissolution of the alloy is followed by redeposition of Cu and formation of Cu2O. In 0.1 N NaOH selective dissolution of Al was observed and a nanocrystalline layer consisting of Cu2O and FeOOH forms at the open circuit potential as well as during anodic polarization up to -150 mVSHE. At higher potentials Cu-ions dissolve into the electrolyte, which allows building up an Al-hydroxide layer. Presumably due to the loss of Al during polarization phase transforma-tions of the quasicrystals (e.g. continuous transformation or precipitation) were observed by transmission electron microscopy.In order to clarify the influence of the quasicrystalline structure on the corrosion, open circuit potentials and current densities of the quasicrystalline and three ternary crystalline phases with different Al-content, but approximately constant ratio Cu:Fe of 2:1 were compared. Lower current densities, but a less noble open circuit potential for the quasicrystals than expected from the trend over the Al-content indicate a small influence of the quasicrystalline structure.

Microstructure Development in a High Current Density NbTi Superconducting Composite

1985 ◽  
Vol 43 ◽  
pp. 186-189
Author(s):  
P. J. Lee ◽  
D. C. Larbalestier
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Cold Drawing ◽  
Heat Treatments ◽  
Grain Structure ◽  
Fine Grain ◽  
Boundary Film ◽  
Quantitative Basis ◽  
Cold Worked ◽  
Very High

Several features of the metallurgy of superconducting composites of Nb-Ti in a Cu matrix are of interest. The cold drawing strains are generally of order 8-10, producing a very fine grain structure of diameter 30-50 nm. Heat treatments of as little as 3 hours at 300 C (∼ 0.27 TM) produce a thin (1-3 nm) Ti-rich grain boundary film, the precipitate later growing out at triple points to 50-100 nm dia. Further plastic deformation of these larger a-Ti precipitates by strains of 3-4 produces an elongated ribbon morphology (of order 3 x 50 nm in transverse section) and it is the thickness and separation of these precipitates which are believed to control the superconducting properties. The present paper describes initial attempts to put our understanding of the metallurgy of these heavily cold-worked composites on a quantitative basis. The composite studied was fabricated in our own laboratory, using six intermediate heat treatments. This process enabled very high critical current density (Jc) values to be obtained. Samples were cut from the composite at many processing stages and a report of the structure of a number of these samples is made here.

Adsorption and Oxidation of Thiosulfate on the Platinum Electrode in a Slightly Alkaline Medium

2000 ◽  
Vol 65 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Tomáš Loučka
Keyword(s):  
Alkaline Medium ◽  
Oxidation Reaction ◽  
Open Circuit Potential ◽  
Platinum Electrode ◽  
Adsorbed Layer ◽  
Open Circuit ◽  
Adsorbed Hydrogen ◽  
Oxidation Number ◽  
Hydrogen Electrode ◽  
Layer Region

The aim of this research was to study the oxidation and reduction of the adsorbed thiosulfate on the platinum electrode in a slightly alkaline medium. The adsorption was performed at the open circuit conditions. The reduction of the adsorbed layer in the hydrogen region is slower in a slightly alkaline medium than in acid. The mechanism of reduction and oxidation of adsorbed molecules is probably the same. The nonstationary currents measured in presence of thiosulfates showed that the change in the oxidation number does not take place during the adsorption in the double layer region. In the hydrogen region, thiosulfate replaces the adsorbed hydrogen while beeing reduced. Nonstationary currents at higher concentrations of thiosulfate indicate the presence of more layers on the electrode. Upon reaching higher concentrations of thiosulfate the oxidation reaction takes place between thiosulfate in solution and adsorbed product of its reduction. The open circuit potential of the platinum electrode measured in a thiosulfate solution was 0.780 and 0.783 V against the hydrogen electrode in the same solution.

scholarly journals Effects of Alloying Elements on the Corrosion Behavior of Sputter–deposited Zr–(12–21)Cr–W Alloys in 0.5 M NaCl Solution

1970 ◽  
Vol 25 ◽  
pp. 75-82
Author(s):  
Basu Ram Aryal ◽  
Jagadeesh Bhattarai
Keyword(s):  
Corrosion Test ◽  
Open Circuit Potential ◽  
Chemical Society ◽  
Open Circuit ◽  
Sputter Deposition ◽  
Nacl Solution ◽  
Corrosion Rates ◽  
Sputter Deposited ◽  
Stable Passivity ◽  
Zirconium Metal

The synergistic effect of the simultaneous additions of tungsten and zirconium in thesputter-deposited amorphous or nanocrystalline Zr-(12-21)Cr-W alloys is studied in 0.5 MNaCl solution open to air at 25°C using corrosion tests and open circuit potentialmeasurements. Corrosion rates of the sputter-deposited Zr-(12-21)Cr-W alloys containing10-80 at % tungsten (that is, 0.95-1.85 x 10-2 mm.y-1) are more than one order of magnitudelower than that of the sputter-deposited tungsten and even lower than those of zirconium aswell as chromium in 0.5 M NaCl solution. The addition of 8-73 at % zirconium content inthe sputter-deposited binary W-(12-21)Cr alloys seems to be more effective to improve thecorrosion-resistant properties of the sputter-deposited ternary Zr-Cr-W alloys containing12-21 at % chromium in 0.5 M NaCl solution. The sputter-deposited Zr-(17-21)Cr-W alloyscontaining an adequate amounts of zirconium metal showed the more stable passivity andshowed higher corrosion resistance than those of alloy-constituting elements in 0.5 M NaClsolution open to air at 25°C.Keywords: Zr-(12-21)Cr-W alloys, sputter deposition, corrosion test, open circuit potential,0.5 M NaCl.DOI:  10.3126/jncs.v25i0.3305Journal of Nepal Chemical Society Volume 25, 2010 pp 75-82

scholarly journals Miniaturization effect of electroosmotic self-propulsive microswimmer powered by biofuel cell

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Toshiro Yamanaka ◽  
Fumihito Arai
Keyword(s):  
Theoretical Model ◽  
Femtosecond Laser ◽  
Polymer Composites ◽  
Open Circuit Potential ◽  
Vascular System ◽  
Conductive Polymer ◽  
Open Circuit ◽  
Biofuel Cell ◽  
Remarkable Feature ◽  
Conductive Polymer Composites

AbstractFor future medical microrobotics, we have proposed the concept of the electroosmotic self-propulsive microswimmer powered by biofuel cell. According to the derived theoretical model, its self-propulsion velocity is inversely proportional to the length of the microswimmer, while it is proportional to the open circuit potential generated by the biofuel cell which does not depend on its size. Therefore, under conditions where those mechanisms work, it can be expected that the smaller its microswimmer size, the faster its self-propulsion velocity. Because of its remarkable feature, this concept is considered to be suitable as propulsion mechanisms for future medical microrobots to move inside the human body through the vascular system, including capillaries. We have already proved the mechanisms by observing the several 10 μm/s velocity of 100 μm prototypes fabricated by the optical photolithography using several photomasks and alignment steps. However, the standard photolithography was not suitable for further miniaturization of prototypes due to its insufficient resolution. In this research, we adopted femtosecond-laser 3D microlithography for multi-materials composing of the conductive polymer composites and nonconductive polymer composite and succeeded in fabricating 10 μm prototypes. Then we demonstrated more than 100 μm/s velocity of the prototype experimentally and proved its validity of the smaller and faster feature.

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