Study on Present Situation and New Trends of the Electrodeposition of Nickel-Cobalt Alloy

2012 ◽  
Vol 535-537 ◽  
pp. 973-976 ◽  
Author(s):  
Ming Ming Yu ◽  
Hong You Li ◽  
Yi Wang
Keyword(s):  
Ph Value ◽  
Co2 Reduction ◽  
Present Situation ◽  
Cathodic Current Density ◽  
Cobalt Alloy ◽  
Cathodic Current ◽  
Anomalous Codeposition ◽  
Nickel Cobalt ◽  
High Microhardness ◽  
Main Factor

Nickel-cobalt alloys have broad application prospect for their excellent properties (i.e. high microhardness, strength, abrasion, corrosion resistance and magnetic properties.etc). Present situation and new trends on mechanism of the anomalous codeposition and technology of electrodepostion of nickel-cobalt were studied. Effects of electrolysis parameters (e.g. concentration of co2+in the electrolyte, cathodic current density, pH value, temperature.etc) on the alloy composition, morphology and mechanical properties were analyzed. The formation of the monovalent intermediate (hydroxides or colloid) may cause the cobalt preferential deposition or the faster charge-transfer of Co2+ reduction compared to that of Ni2+ reduction is the main factor that causes the anomalous codeposition behavior of the nickel-cobalt alloy.

Electrodeposition of Fe-Diamond Composite Material for Manufacture of Diamond Tools

2010 ◽  
Vol 37-38 ◽  
pp. 398-401 ◽  
Author(s):  
Bing Suo Pan ◽  
Xiao Hong Fang ◽  
Yong Chang Tian
Keyword(s):  
Ammonium Chloride ◽  
Current Density ◽  
Ph Value ◽  
Matrix Material ◽  
Chloride Concentration ◽  
Cathodic Current Density ◽  
Iron Deposit ◽  
Cathodic Current ◽  
Diamond Tools ◽  
Diamond Bit

For machining of hard and brittle materials, iron electrodeposit is a kind of matrix material with potential advantages for manufacture of diamond tools. Aiming at the problem of difficult codeposition of diamond in iron deposit, this paper adopts orthogonal design of experiment to study the effects of solution pH value, cathodic current density, alkylphenol polyoxyethylene (10) ether (OP-10) concentration and ammonium chloride concentration on codeposition of diamond, and then Fe-based diamond bits were fabricated and drilling tests in granite were carried out. The results show that pH value, cathodic current density, OP-10 concentration and ammonium chloride concentration all have statistically significant effect on codeposition of diamond in iron deposit, whose contributions to the variance of the weight of codeposited diamond are 37.45%, 32.05%, 13.13% and 12.38%, respectively. The result of drilling test indicates that Fe-based diamond bit can achieve much higher penetration rate than common Ni-based diamond bit.

scholarly journals Electrodeposition of Copper and Brass Coatings with Olive-Like Structure

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1762
Author(s):  
Artur Maciej ◽  
Natalia Łatanik ◽  
Maciej Sowa ◽  
Izabela Matuła ◽  
Wojciech Simka
Keyword(s):  
Corrosion Resistance ◽  
Cathodic Current Density ◽  
Bath Composition ◽  
Cathodic Current ◽  
Corrosion Properties ◽  
Fine Grained ◽  
Electrodeposited Coating ◽  
Copper Zinc ◽  
New Generation ◽  
First Time

One method of creating a brass coating is through electrodeposition, which is most often completed in cyanide galvanic baths. Due to their toxicity, many investigations focused on the development of more environmentally friendly alternatives. The purpose of the study was to explore a new generation of non-aqueous cyanide-free baths based on 1-ethyl-3-methylimidazolium acetate ionic liquids. The study involved the formation of copper, zinc, and brass coatings. The influence of the bath composition, cathodic current density, and temperature was determined. The obtained coatings were characterized in terms of their morphology, chemical composition, phase composition, roughness, and corrosion resistance. It was found that the structure of the obtained coatings is strongly dependent on the process parameters. The three main structure types observed were as follows: fine-grained, porous, and olive-like. To the best knowledge of the authors, it is the first time the olive-like structure was observed in the case of an electrodeposited coating. The Cu-Zn coatings consisted of 19–96 at. % copper and exhibited relatively good corrosion resistance. A significant improvement of corrosion properties was found in the case of copper and brass coatings with the olive-like structure.

Comparative Cathodic Behavior of ~9% Cr and Plain Steel Reinforcement in Concrete

CORROSION ◽  
2012 ◽  
Vol 68 (4) ◽  
pp. 045003-1-045003-10 ◽  
Author(s):  
M. Akhoondan ◽  
A.A. Sagüés
Keyword(s):  
Carbon Steel ◽  
Oxygen Reduction ◽  
Current Density ◽  
Surface Condition ◽  
Corrosion Current ◽  
Reduction Reaction ◽  
Cathodic Current Density ◽  
Cathodic Current ◽  
Steel Rebar ◽  
Cathodic Region

The extent of the oxygen reduction reaction in concrete was evaluated for ~9% Cr rebar approaching the ASTM A1035 specification and compared to that of conventional carbon steel rebar, at ages of up to ~1 year. Cathodic strength was measured by the cathodic current density developed at −0.35 V vs. copper/copper sulfate (Cu/CuSO4 [CSE]) and −0.40 VCSE in cyclic cathodic potentiodynamic polarization tests, both in the as-received condition with mill scale and with scale removed by glass bead surface blasting. In both conditions the ~9% Cr alloy was a substantially weaker cathode, by a factor of several fold, than carbon steel. Within each material, the surface-blasted condition yielded also much lower cathodic current density than the as-received condition. For a small anode-large cathode system with a given anode polarization function, and no important oxygen reduction concentration polarization, the corrosion current was projected to be significantly lower if the cathodic region were ~9% Cr instead of plain steel rebar with comparable surface condition. There was strong correlation between the charge storage capability of the interface and the extent of cathodic reaction of oxygen. The result cannot be ascribed solely to differences in effective surface area between the different materials and conditions.

Controlling factors in localised corrosion morphologies observed for magnesium immersed in chloride containing electrolyte

2015 ◽  
Vol 180 ◽  
pp. 313-330 ◽  
Author(s):  
Geraint Williams ◽  
Nick Birbilis ◽  
H. Neil McMurray
Keyword(s):  
Current Density ◽  
Radial Growth ◽  
Cathodic Current Density ◽  
Nacl Solution ◽  
High Concentration ◽  
Cathodic Current ◽  
Density Distributions ◽  
Filiform Corrosion ◽  
Density Values ◽  
Current Densities

The early stages of localised corrosion affecting magnesium (Mg) surfaces when immersed in aqueous sodium chloride (NaCl) solutions involves the propagation of dark regions, within which both anodic metal dissolution and cathodic hydrogen evolution occur. For nominally “pure” Mg, these dark areas can either take the form of discs which expand radially with time, or filiform-like tracks which lengthen with time. For Mg surfaces which display disc-form corrosion features in concentrated NaCl electrolyte, a transition to filiform corrosion (FFC) is observed as the concentration is decreased, indicating ohmic constraints on radial propagation. A similar effect is observed when Mg specimens of different iron impurity are immersed in a fixed, high concentration NaCl solution, where disc-form corrosion is observed on samples having ≥280 ppm Fe, but FFC predominates at ≤80 ppm Fe. An in situ scanning vibrating electrode technique (SVET) is used to determine current density distributions within the propagating corrosion features. Cathodic current density values of between −100 and −150 A m−2 measured in central areas of disc-like features are sufficient to sustain the radial growth of a local anode at the perimeter of the discs. However, for high purity Mg specimens (≤80 ppm Fe), cathodic current densities of −10 A m−2 or less are measured over FFC affected regions, indicating that linear propagation arises when there is insufficient cathodic current produced on the corroded surface to sustain radial growth. The results are consistent with surface control of localised corrosion propagation in concentrated electrolyte, but ohmic control in dilute, lower conductivity NaCl solution.

Nickel–cobalt alloy doping phosphorus as advanced electrocatalyst for hydrazine oxidation

2019 ◽  
Vol 807 ◽  
pp. 151648 ◽  
Author(s):  
Bing Liang ◽  
Yahui Wang ◽  
Xianyi Liu ◽  
Ting Tan ◽  
Linwei Zhang ◽  
...  
Keyword(s):  
Cobalt Alloy ◽  
Nickel Cobalt ◽  
Hydrazine Oxidation
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