scholarly journals Effects of Complexing Agents and Current Density on Carbon Content of Trivalent Chromium Carbon Coating and Its Properties

2016 ◽  
pp. 7099-7110 ◽  
Author(s):  
Hung-Hua Sheu ◽  
Keyword(s):  
Carbon Content ◽  
Current Density ◽  
Carbon Coating ◽  
Trivalent Chromium ◽  
Complexing Agents

scholarly journals Preparation and Characterization of Nanocrystalline Hard Chromium Coatings Using Eco-Friendly Trivalent Chromium Bath

2011 ◽  
Vol 8 (4) ◽  
pp. 1925-1929 ◽  
Author(s):  
V. S. Protsenko ◽  
V. O Gordiienko ◽  
F. I. Danilov ◽  
S. C. Kwon
Keyword(s):  
Formic Acid ◽  
Current Density ◽  
Nanocrystalline Structure ◽  
Cathode Current Density ◽  
Trivalent Chromium ◽  
Complexing Agents ◽  
Hard Chromium ◽  
Cathode Current

A new aqueous sulfate trivalent chromium bath is described. The chromium bath contains formic acid and carbamide as complexing agents. Chromium was deposited at a temperature of 30÷40oC and a cathode current density of 10÷25 A dm-2. The bath allows obtaining thick (up to several hundred micrometers) hard chromium coatings with nanocrystalline structure. The electrodeposition rate reaches 0.8÷0.9 µm min-1.

The removal of the trivalent chromium from the leather tannery wastewater: the optimisation of the electro-coagulation process parameters

2011 ◽  
Vol 63 (3) ◽  
pp. 385-394 ◽  
Author(s):  
E. GilPavas ◽  
I. Dobrosz-Gómez ◽  
M. Á. Gómez-García
Keyword(s):  
Current Density ◽  
Oxygen Demand ◽  
Trivalent Chromium ◽  
Biological Oxygen Demand ◽  
Optimal Conditions ◽  
Electrode Gap ◽  
Surface Method ◽  
Response Capacity ◽  
Electro Coagulation ◽  
Parameter Values

The capacity of the electro-coagulation (EC) process for the treatment of the wastewater containing Cr3+, resulting from a leather tannery industry placed in Medellin (Colombia), was evaluated. In order to assess the effect of some parameters, such as: the electrode type (Al and/or Fe), the distance between electrodes, the current density, the stirring velocity, and the initial Cr3+ concentration on its efficiency of removal (%RCr+3), a multifactorial experimental design was used. The %RCr3+ was defined as the response variable for the statistical analysis. In order to optimise the operational values for the chosen parameters, the response surface method (RSM) was applied. Additionally, the Biological Oxygen Demand (BOD5), the Chemical Oxygen Demand (COD), and the Total Organic Carbon (TOC) were monitored during the EC process. The electrodes made of aluminium appeared to be the most effective in the chromium removal from the wastewater under study. At pH equal to 4.52 and at 28°C, the optimal conditions of Cr3+ removal using the EC process were found, as follows: the initial Cr3+ concentration=3,596 mg/L, the electrode gap=0.5 cm, the stirring velocity=382.3 rpm, and the current density=57.87 mA/cm2. At those conditions, it was possible to reach 99.76% of Cr3+removal, and 64% and 61% of mineralisation (TOC) and COD removal, respectively. A kinetic analysis was performed in order to verify the response capacity of the EC process at optimised parameter values.

The enhanced rate performance of LiFe0.5Mn0.5PO4/C cathode material via synergistic strategies of surfactant-assisted solid state method and carbon coating

2015 ◽  
Vol 3 (3) ◽  
pp. 996-1004 ◽  
Author(s):  
Xue Zhou ◽  
Ye Xie ◽  
Yuanfu Deng ◽  
Xusong Qin ◽  
Guohua Chen
Keyword(s):  
Solid State ◽  
Cathode Material ◽  
Carbon Content ◽  
Carbon Coating ◽  
High Rate ◽  
Cycle Performance ◽  
Rate Performance ◽  
Solid State Method ◽  
State Method ◽  
Surfactant Assisted

A high rate and cycle performance LiFe0.5Mn0.5PO4/C material was obtained by synergies of a surfactant-assisted solid state method and carbon content.

scholarly journals Fe-Ni ALLOY ELECTRODEPOSITION FROM SIMPLE AND COMPLEX TYPE SULFATE ELECTROLYTES CONTAINING Ni/Fe RATIO OF 1 AND 12

2014 ◽  
Vol 44 (1) ◽  
pp. 51-56 ◽  
Author(s):  
M. Moniruzzaman ◽  
K.M. Shorowordi ◽  
A. Azam ◽  
M.F.N. Taufique
Keyword(s):  
Grain Size ◽  
Current Density ◽  
High Current Density ◽  
Complexing Agents ◽  
Alloy Electrodeposition ◽  
Fine Grained ◽  
Ni Alloy ◽  
Iron Nickel ◽  
High Degree ◽  
Density Results

Iron-nickel (Fe-Ni) alloy electrodeposition has been conducted from simple and complex baths having Ni/Fe ratio of 1 and 12. The applied current density varies from 30 to 100 mA/cm2. The coating composition, morphology and microhardness are measured and characterized by SEM/EDX and Shimadzu microhardness tester. The percentage of Ni in the coating increases with increasing current density and the Ni/Fe ratio of electrolytes which is supported by the alloy deposition principle. Fine grained and smooth coating without microcracking is obtained from the complex baths. Complexing agents are supposed to reduce the deposit stress developed during electrodeposition. Increase in Ni/Fe ratio in the bath as well as current density results in decreasing grain size of the deposits. High current density is believed to give rise to a high degree of adatoms at the electrode surface and high degree of adatoms decreases the grain size. Microhardness of the coating increases with the increase of bath Ni/Fe ratio as well as current density of electrodeposition. DOI: http://dx.doi.org/10.3329/jme.v44i1.19498

ELECTRIDEPOSITION AND WEAR BEHAVIOR OF NANO-STRUCTURED Cr-WC COMPOSITE COATINGS FROM A TRIVALENT CHROMIUM BATH

2012 ◽  
Vol 05 ◽  
pp. 737-743 ◽  
Author(s):  
A. AMADEH ◽  
S. NADALI ◽  
S.M. LARI BAGHAL ◽  
H. MORADI
Keyword(s):  
Wear Resistance ◽  
Current Density ◽  
Duty Cycle ◽  
Wear Behavior ◽  
Composite Coatings ◽  
Sodium Dodecyl ◽  
Trivalent Chromium ◽  
Sodium Saccharin ◽  
Average Size ◽  
Pin On Disk

Electrodeposition of nano-structured Cr - WC had been carried out from a trivalent chromium bath using a square shaped pulse current. The average size of WC particles was 70 nm. The effect of sodium saccharin and sodium dodecyl sulfate (SDS) additives as well as pulse electroplating parameters such as current density, duty cycle and frequency on the amount of incorporated WC particles and morphology of the coatings was investigated. The structure and morphology of the coatings were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. In addition, the hardness and tribological behavior of the coatings were investigated by microhardness and pin on disk methods, respectively. The results showed that although the addition of saccharin and SDS decreased the amount of WC particles in the coating, but reduced the size of WC agglomerates which, in turn, increased the wear resistance of the coatings. Also, the optimum wear resistance was achieved at the current density of 8 A/dm2, duty cycle of 50% and frequency of 10 Hz.

Carbon-Coating Layers on Boron Generated High Critical Current Density in MgB2 Superconductor

2020 ◽  
Vol 12 (7) ◽  
pp. 8563-8572 ◽  
Author(s):  
Haobo Liu ◽  
Jiancheng Li ◽  
Mingjie Sun ◽  
Jiangtao Qu ◽  
Rongkun Zheng ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Carbon Coating ◽  
Mgb2 Superconductor ◽  
High Critical Current Density ◽  
Coating Layers

Effect of Carbon Coating of TiO2/Fe3O4 Particles on Their Photocatalytic Activity

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Tarek A. Gad Allah ◽  
Shigeru Kato ◽  
Shigeo Satokawa ◽  
Toshinori Kojima
Keyword(s):  
Methyl Orange ◽  
Carbon Content ◽  
Surface Area ◽  
Carbon Coating ◽  
Degradation Rate ◽  
Sol Gel ◽  
Bet Surface Area ◽  
Poly Vinyl Alcohol ◽  
Titanium Tetraisopropoxide ◽  
X Ray

Magnetic titanium dioxide particles were prepared by depositing different amounts of TiO2 on magnetite powder using a sol-gel process. Adsorptivity of TiO2/Fe3O4 particles was increased by carbon coating which was carried out by mixing the particles with poly (vinyl alcohol) as a source of carbon. The carbon coating and calcination of particles were carried out simultaneously by heating the mixture at different temperatures. X-ray diffraction, energy dispersion fluorescence x-ray spectrometry, carbon-nitrogen analyzer and surface area analysis were used for the characterization of the prepared samples. The phase transition temperature of TiO2 from anatase to rutile was found to decrease by decreasing titanium tetraisopropoxide to magnetite (TTIP:Fe3O4) ratio while BET surface area increased by increasing this ratio. Carbon content had a significant effect on the formed phases and surface areas of the samples. The photocatalytic efficiencies of the prepared samples were investigated against degradation of methyl orange. The effect of TTIP:Fe3O4 ratio and carbon content on the degradation rate were studied. Methyl orange degradation rate increased with the increase in TTIP:Fe3O4 ratio but decreased by increasing carbon content.

scholarly journals Influence of Carbon Content on Superconductivity of Bi2Sr2CaCu2Ox

2017 ◽  
Vol 5 (1) ◽  
pp. 77
Author(s):  
Deawha Soh ◽  
Zhanguo Fan ◽  
N. Korobova
Keyword(s):  
Solid State ◽  
Grain Boundary ◽  
Critical Current Density ◽  
Carbon Content ◽  
Critical Current ◽  
Conventional Method ◽  
Current Density ◽  
Solid State Reaction ◽  
Sintering Process ◽  
Shs Method

<p>Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>X</sub> was prepared by the conventional method of solid state reaction and SHS method. The samples were annealed in different atmosphere in order to examine the influence of atmospheres on the carbon contents in the Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>X</sub> compound. The lowest carbon content in Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>X</sub> could be attended when the sample was annealed in O<sub>2</sub> at 800 °C for 100 hours. The CO<sub>2</sub> in air pollute the samples and increase the carbon content in the sintering process. The critical current density of the Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>X</sub> samples will decrease with the increasing carbon contents in the samples. The impurity carbon will deposit in the grain boundary, which makes critical current density lower.</p>

scholarly journals Copper Recovery From Ammonia Solutions Through Electro-Electrodialysis (EED)

2021 ◽  
Vol 8 ◽  
Author(s):  
Belen Garrido ◽  
Gerardo Cifuentes ◽  
Pedro Fredes ◽  
Eduardo Pino ◽  
Cristian Calderón ◽  
...  
Keyword(s):  
Solvent Extraction ◽  
Ion Exchange ◽  
Current Efficiency ◽  
Current Density ◽  
Electrochemical Process ◽  
Copper Recovery ◽  
Complexing Agents ◽  
Unit Operation ◽  
Alkaline Leaching ◽  
Interesting Alternative

Alkaline leaching with highly selective ammoniacal complexing agents is an interesting alternative for the treatment of copper concentrates. This treatment is beneficial for copper recovery because it allows the formation of soluble amines complexes, with cupric tetramine ( Cu(NH3)42+) being the most stable. In order to suppress the unit operation of solvent extraction (SX) and move directly to the electrochemical process, an electro-electrodialysis (EED) process using ion exchange membranes to obtain copper is proposed. The study contemplates the operation with synthetic ammonia solutions containing copper at different concentrations and current density under standard conditions of pressure and temperature. The presented data demonstrate that the concentration of copper in the solution and the excess of ammonia are inversely related to the efficiency of the current and the voltage of the cell, whereas an increase in current density causes an increase in current efficiency, contrary to what happens in sulfuric systems.

Improving the Electrochemical Performance of LiFePO4/C Cathode by Selection of Carbon Source

2012 ◽  
Vol 217-219 ◽  
pp. 785-791
Author(s):  
Yan Lin ◽  
Xiao Hua Huang ◽  
Ren Qin Guo ◽  
Ai Jiao Xu ◽  
Qin Yi Shi
Keyword(s):  
Citric Acid ◽  
Carbon Source ◽  
Ethylene Glycol ◽  
Electrochemical Performance ◽  
Carbon Content ◽  
Electric Vehicles ◽  
Carbon Coating ◽  
Sol Gel ◽  
Voltage Range ◽  
Selection Of

LiFePO4/C composite was synthesized by an easy sol-gel method using FeC2O4•H2O as iron source, citric acid and ethylene glycol as carbon source. The results showed that citric acid was inclined to leave more carbon in the synthesized material than ethylene glycol was and the carbon content increased greatly with the increasing amount of citric acid. When ethylene glycol was applied as carbon source, it left only a few amount of carbon (1.6 wt%) in the material. By optimizing the addition of carbon source, LiFePO4/C particles with uniform carbon coating and a little carbon content was obtained. The LiFePO4/C composite synthesized with 1/1 ratio of ethylene glycol to cations demonstrated the best electrochemical performance with its capacity of 143 mAh/g at 0.1C and 110 mAh/g at 1C within the voltage range of 2.5-4.2V (vs. Li/Li+). The results will provide ideas for the improvement of overall properties of LiFePO4 material for its application in the field of electric vehicles.

Sign in / Sign up

Export Citation Format

Share Document