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 The influence of chloride ion concentration on the localized corrosion of E717 Mg alloy

CORROSION ◽  
10.5006/3601 ◽  
2020 ◽  
Author(s):  
Christos Kousis ◽  
Neil McMurray ◽  
Patrick Keil ◽  
Geraint Williams
Keyword(s):  
Current Density ◽  
Chloride Concentration ◽  
Leading Edge ◽  
Chloride Ion ◽  
Cathodic Current Density ◽  
Ion Concentration ◽  
Localized Corrosion ◽  
Anodic Current Density ◽  
Cathodic Current ◽  
Density Values

The localized corrosion behavior of E717 magnesium alloy immersed in chloride-containing electrolyte is investigated using an in-situ scanning vibrating electrode technique (SVET), coupled with time-lapse imaging (TLI). It is shown that initiation of localized corrosion in chloride-containing electrolyte is characterized by the appearance of discrete local anodes, corresponding with the leading edges of dark, filiform like features, which combine with time to produce a mobile anodic front. The size and growth rate of these features are highly dependent on the chloride ion concentration of the electrolyte. SVET-derived current density maps reveal that the corroded surface left behind the anodic front is cathodically activated, where cathodic current density values progressively decline with increasing distance away from the anodic leading edge. The intensity of localized anodes is highly dependent on the chloride ion concentration, where progressively higher local anodic current density values are observed with increasing chloride ion concentration along with progressively higher rates of volumetrically-determined hydrogen evolution. Breakdown potential, measured using time-dependent free corrosion potential transients and potentiodynamic polarization at neutral and elevated pH respectively, is shown to vary with the logarithm of chloride ion concentration and the time for localized corrosion initiation is progressively increased with decreasing chloride concentration. From the combination of results which are presented herein, the underlying reasons for the influence of chloride ion concentration on the localized corrosion characteristics of E717 alloy will be discussed.

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.

scholarly journals Hydrogen Absorption and Desorption in Steel by Electrolytic Charging

2006 ◽  
Vol 15-17 ◽  
pp. 816-821 ◽  
Author(s):  
Geert Mertens ◽  
Lode Duprez ◽  
Bruno C. De Cooman ◽  
Marc Verhaege
Keyword(s):  
Current Density ◽  
Hydrogen Absorption ◽  
Failure Mechanisms ◽  
Great Influence ◽  
Hydrogen Desorption ◽  
Cathodic Current Density ◽  
Cathodic Current ◽  
Charging Current ◽  
Current Densities ◽  
Profound Insight

The presence of hydrogen in steel decreases its toughness and formability leading to hydrogen embrittlement. To understand the failure mechanisms of steel due to the presence of hydrogen, a profound insight in the hydrogen household of the steel is needed. This includes a study of the solubility, the diffusion and the trapping of hydrogen. Next, the absorption and desorption behavior during and after electrolytic charging must be well determined. This was investigated in this research for steels with various types of traps, e.g. dislocations, microcracks, grain boundaries and precipitates such as TiC and Ti4C2S2. The samples were cathodically charged at three different current densities: 0.8mA/cm2; 8.3mA/cm2 and 62.5mA/cm2. It was noticed that the cathodic current density used for hydrogen loading had a great influence on the results. Observation of the samples by scanning electron microscopy (SEM) showed that at the highest current density major damage of the surface had occurred. Hence it was decided to study more systematically the influence of charging current density on the resulting surface aspect and on hydrogen absorption and desorption. The hydrogen charging kinetics, maximum hydrogen solubility and hydrogen desorption behavior have also been evaluated for the different current densities during charging.

Experimental Research on Electroforming Nano-ZrO2 Reinforced Cu-Matrix Composite Aided by Pulse Power

2018 ◽  
Vol 764 ◽  
pp. 95-105
Author(s):  
Zhong Wen Sima ◽  
Zhi Yong Li ◽  
Hong Bin Cui ◽  
Hun Guo
Keyword(s):  
Surface Morphology ◽  
Matrix Composite ◽  
Current Density ◽  
Duty Cycle ◽  
Pulse Frequency ◽  
Cathodic Current Density ◽  
Ultrasonic Power ◽  
Cathodic Current ◽  
Maximum Content ◽  
Cycle Pulse

Prepared the nanoZrO2 reinforced Cu-matrix composite by pulse electroforming. The effects of the content of nanoZrO2 particle in the casting solution, average cathodic current density, duty cycle, pulse frequency and ultrasonic power on the content of nanoZrO2 in the electroforming Cu-matrix composite have been studied. The microhardness and surface morphology of Cu-ZrO2 composite were analyzed. The experimental results demonstrate that the maximum content of nanoZrO2 in the electroforming Cu-ZrO2 composite is 2.94%, microhardness is 492 HV, which is significantly improved compared with pulse pure copper’s 337 HV, when the content of nanoZrO2 is 40 g/L, average cathodic current density is 4A/dm2, duty cycle is 0.2 , pulse frequency is 1100 Hz and ultrasonic power is 20w .The surface of composite prepared by pulse electroforming is more smooth, organization is denser, grain is finer and agglomeration of nanoZrO2 particles is fewer compared with Direct-current electroforming nanoZrO2 reinforced Cu-ZrO2 composite.

A High-Speed Nickel Plating Bath for Manufacture of Diamond Tools

2007 ◽  
Vol 359-360 ◽  
pp. 68-72
Author(s):  
Bing Suo Pan ◽  
Yang Yang
Keyword(s):  
Ammonium Sulphate ◽  
High Speed ◽  
Ph Value ◽  
Sodium Formate ◽  
Crystal Form ◽  
Nickel Plating ◽  
Plating Bath ◽  
Diamond Tools ◽  
Plating Solution ◽  
Diamond Bit

To increase the manufacture efficiency of electroplated diamond tools, a nickel plating solution containing ammonium sulphate and sodium formate was investigated. The effects of concentration of ammonium sulphate, sodium formate and pH value on throwing power, covering power, ability to resist Cu2+ contamination and deposit microhardness were studied. Surface topography of deposits was also observed by SEM. Compared to watts bath, the plating solution studied is advantageous in terms of the performance of plating solution, deposit hardness and diamond bit behavior. Ammonium sulphate can refine deposit crystal grains and result in crystal form change.

Electrochemical Behaviour and Electrorefining of Cobalt in NaCl-KCl-K2TiF6 Melt

2009 ◽  
Vol 64 (7-8) ◽  
pp. 485-491 ◽  
Author(s):  
Sergey A. Kuznetsov ◽  
Olga S. Kazakova ◽  
Olga V. Makarova
Keyword(s):  
Current Density ◽  
Electrochemical Behaviour ◽  
Linear Sweep Voltammetry ◽  
Cathodic Current Density ◽  
Argon Atmosphere ◽  
Limiting Current ◽  
Linear Sweep ◽  
Cathodic Current ◽  
Limiting Current Density ◽  
The Right

AbstractThe electrorefining of cobalt in NaCl-KCl-K2TiF6 (20 wt%) melt has been investigated. It was shown that complexes of Ti(III) and Co(II) appeared in the melt due to the reaction 2Ti(IV) + Co → 2Ti(III) + Co(II) and this reaction was entirely shifted to the right hand side. On the base of linear sweep voltammetry diagnostic criteria it was found that the discharge of Co(II) to Co metal is controlled by diffusion. The limiting current density of discharge Co(II) to metal in NaCl-KCl-K2TiF6 (20 wt%) melt was determined by steady-state voltammetry. The electrorefining of cobalt was carried out in hermetic electrolyser under argon atmosphere. Initial cathodic current density was changed from 0.2 Acm−2 up to 0.7 Acm−2, the electrolysis temperature varied within 973 - 1123 K. Behaviour of impurities during cobalt electrorefining was discussed. It was shown that electrorefining led to the elimination of most of the interstitial impurities (H2, N2, O2, C), with the result that the remaining impurity levels below 10 ppm impart high ductility to cobalt.

Corrosion Resistance of High-Alloyed Material UNS N08028 in Sodium Chloride Solution

2014 ◽  
Vol 893 ◽  
pp. 440-443
Author(s):  
Li Na Zhang ◽  
Jerzy A. Szpunar ◽  
Jian Xin Dong ◽  
Mai Cang Zhang
Keyword(s):  
Corrosion Resistance ◽  
Sodium Chloride ◽  
Corrosion Rate ◽  
Current Density ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Corrosion Potential ◽  
Ph Value ◽  
Chloride Concentration ◽  
Decreasing Ph

The influence of ions chloride concentration and pH value on the corrosion resistance of high-alloyed material UNS N08028 in the sodium chloride solution is investigated. Results show that the corrosion potential is active cathodically with the increase of chloride concentration. The current density and corrosion rate both increase with increasing chloride concentration and decreasing pH value.

Cathodic Protection of Iron In the Temperature Range 25 C-92 C★

CORROSION ◽  
1958 ◽  
Vol 14 (4) ◽  
pp. 54-56 ◽  
Author(s):  
G. R. HOEY ◽  
M. COHEN
Keyword(s):  
Current Density ◽  
Cathodic Protection ◽  
Cathodic Polarization ◽  
Open Circuit ◽  
Cathodic Current Density ◽  
Oxygen Solubility ◽  
Nacl Solution ◽  
Cathodic Current ◽  
Temperature Range ◽  
Higher Temperature

Abstract The cathodic protection of iron was studied in the temperature range 25 C to 92 C. The limiting protective current density and the open circuit cathodic current density for iron in dilute NaCl solution goes through a temperature maximum at roughly 75 C. This is explained in terms of the effect of decreasing oxygen solubility at the higher temperature on the local cathodic reaction, 2H+ + O2 + 4e = 20H- Iron corrodes under cathodic control at room temperature, whereas at the higher temperatures there is a mixed cathodic-anodic control. Cathodic polarization curves for iron in dilute NaCl solution were obtained in the temperature range 25 C to 92 C. Unsteady potentials were observed in the vicinity of the limiting protective current, whereas at higher and lower currents, steady potentials were observed. The current density at which the potential of the iron reaches —0.5 volt on the hydrogen scale gives satisfactory protection. The nature of the corrosion products of iron is unaffected by temperature in the range studied. 5.2.2

Porous Co–P foam as an efficient bifunctional electrocatalyst for hydrogen and oxygen evolution reactions

2016 ◽  
Vol 4 (47) ◽  
pp. 18272-18277 ◽  
Author(s):  
SeKwon Oh ◽  
HyoWon Kim ◽  
YongKuen Kwon ◽  
MinJoong Kim ◽  
EunAe Cho ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Current Density ◽  
High Performance ◽  
Cathodic Current Density ◽  
Cathodic Current ◽  
Bifunctional Electrocatalyst ◽  
One Step

A high-performance bifunctional Co–P foam catalyst was successfully synthesized by facile one-step electrodeposition at a high cathodic current density.

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