Direct synthesis of nickel powders from NiO slurry by hydrothermal hydrogen reduction process

2010 ◽  
Vol 102 (1-4) ◽  
pp. 101-104 ◽  
Author(s):  
Jong-Gwan Ahn ◽  
Hoang Tri Hai ◽  
Dong-Jin Kim ◽  
Je-Shin Park ◽  
Sang-Bae Kim
Keyword(s):  
Hydrogen Reduction ◽  
Direct Synthesis ◽  
Reduction Process ◽  
Nickel Powders

Copper Chemical Vapor Deposition using a Novel Cu(II) Precursor for Contact Via Filling Process

2007 ◽  
Vol 990 ◽  
Author(s):  
Hideaki Zama ◽  
Yuuji Nishimura ◽  
Michiyo Yago ◽  
Mikio Watanabe
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Hydrogen Reduction ◽  
Reduction Process ◽  
Chemical Vapor ◽  
Molar Ratio ◽  
Cu Films ◽  
Pure Cu ◽  
Substrate Temperatures ◽  
Advanced Generation

ABSTRACTChemical vapor deposition (CVD) of copper using both a novel Cu(II) β-diketonate source and hydrogen reduction process was studied to fill contact vias with the smallest diameter in the 32nm and more advanced generation chip. Pure Cu films were grown under the condition with the product of hydrogen partial pressure and H2/Cu source molar ratio being over 1,000,000. We succeeded in filling the 40-nm-diameter contact vias by optimizing the growth condition of the Cu-CVD in both substrate temperatures and reaction pressures.

Kinetics of synthesizing process for obtaining iron nanopowder by chemical-metallurgical method under isothermal conditions

2021 ◽  
pp. 72-77
Author(s):  
Tien Hiep Nguyen ◽  
◽  
Van Minh Nguyen ◽  
Keyword(s):  
Hydrogen Reduction ◽  
Average Particle Size ◽  
Chemical Deposition ◽  
Reduction Process ◽  
Nitrogen Adsorption ◽  
Specific Rate ◽  
Average Particle ◽  
Isothermal Conditions ◽  
Electron Microscopes ◽  
Kinetics Of

In this work the kinetics of synthesizing process of metallic iron nanopowder by hydrogen reduction from α-FeOOH hydroxide under isothermal conditions were studied. α-FeOOH nanopowder was prepared in advance by chemical deposition from aqueous solutions of iron nitrate Fe(NO3)3 (10 wt. %) and alkali NaOH (10 wt. %) at room temperature, pH = 11, under the condition of continuous stirring. The hydrogen reduction process of α-FeOOH nanopowder under isothermal conditions was carried out in a tube furnace in the temperature range from 390 to 470 °C. The study of the crystal structure and composition of the powders was performed by X-ray phase analysis. The specific surface area S of the samples was measured using BET method by low-temperature nitrogen adsorption. The average particle size D of powders was determined via the measured S value. The size characteristics and morphology of the particles were investigated by transmission and scanning electron microscopes. The calculation of the kinetic parameters of the hydrogen reduction process of α-FeOOH under isothermal conditions was carried out by the Gray-Weddington model and Arrhenius equation. It is shown that the rate constant of reduction at 470 °C is approximately 2.2 times higher than in the case at 390 °C. The effective activation energy of synthesizing process of iron nanopowder by hydrogen reduction from α-FeOOH was ~38 kJ/mol, which indicates a mixed reaction mode. In this case, the kinetics overall process is limited by both the kinetics of the chemical reaction and the kinetics of diffusion, respectively, an expedient way to accelerate the process by increasing the temperature or eliminate the diffusion layer of the reduction product by intensive mixing. It is show that Fe nanoparticles obtained by hydrogen reduction of its hydroxide at 410 °C, corresponding to the maximum specific rate of the reduction process, are mainly irregular in shape, evenly distributed, the size of which ranges from several dozens to 100 nm with an average value of 75 nm.

Kinetic study on preparation of substoichiometric tungsten oxide WO2.72 via hydrogen reduction process

2018 ◽  
Vol 137 (2) ◽  
pp. 389-397 ◽  
Author(s):  
Dan Qiao ◽  
Yue Wang ◽  
Fan Li ◽  
Daya Wang ◽  
Baijun Yan
Keyword(s):  
Kinetic Study ◽  
Tungsten Oxide ◽  
Hydrogen Reduction ◽  
Reduction Process

scholarly journals A Novel Process for the Synthesis of NaV2O5 Mesocrystals from Alkaline-Stripped Vanadium Solution via the Hydrothermal Hydrogen Reduction Method

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 271
Author(s):  
Guobin Zhang ◽  
Yimin Zhang ◽  
Shenxu Bao ◽  
Liuhong Zhang
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Reduction ◽  
Ph Value ◽  
Hydrothermal Process ◽  
Reduction Process ◽  
Oriented Attachment ◽  
Synthesis Process ◽  
Synthesis Mechanism ◽  
Time Saving ◽  
Synthesis Time

NaV2O5 mesocrystals were successfully synthesized from an alkaline-stripped pentavalent vanadium solution through a novel hydrothermal hydrogen reduction process. The optimal conditions for the hydrogen partial pressure, reaction temperature, initial solution pH value, and reaction time for the pure-phase NaV2O5 synthesis were ascertained to be 4 MPa, 200 °C, 4.0, and 2 h, respectively. The synthesis time (only 2 h) was greatly shortened, by nine times, compared with the most time-saving (18 h) hydrothermal process at present. X-ray diffraction (XRD) analysis revealed that the as-prepared powders demonstrated a typical layered orthorhombic structure of NaV2O5. The purity of the as-prepared NaV2O5 reached up to 99.98%. An electrochemical test showed that the as-prepared NaV2O5 has a potential application in sodium ion batteries. According to scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses, the as-prepared NaV2O5 powders were identified to have rod-like mesocrystals consisting of small rods which preferentially grow along the (010) direction. Furthermore, the phase transformation mechanism and crystal growth mechanism in NaV2O5 preparation were discussed systematically, based on which the synthesis mechanism of NaV2O5 was proposed as pentavalent vanadates pre-sedimentation, hydrogen reduction with dehydration, sodium ions insertion, and finally self-assembly oriented attachment. The synthesis process is characterized as time-saving and low-cost, and thus it may have great application prospects.

Nucleation of Tungsten on Titanium Nitride with Hydrogen Reduction of Tungsten Hexafluoride

1992 ◽  
Vol 282 ◽  
Author(s):  
D. Srinivas ◽  
R. Foster ◽  
S. Marcus ◽  
R. Arora ◽  
H. Rebenne
Keyword(s):  
Titanium Nitride ◽  
Nucleation Rate ◽  
Incubation Time ◽  
Seed Layer ◽  
Total Pressure ◽  
Hydrogen Reduction ◽  
Reduction Process ◽  
Tungsten Hexafluoride ◽  
Short Incubation Time ◽  
Competing Reactions

ABSTRACTIn this work, a hydrogen (H2) reduction process has been developed which gives tungsten (W) nucleation on titanium nitride (TiN) adhesion layers with a very short incubation time, eliminating the need for a silane (SiH4reduced seed layer. The nucleation was found to be strongly dependent on the following factors: temperature of the substrate, total pressure in chamber, and gas introduction sequence into the reactor. Theenhanced nucleation rate has been explained based on two competing reactions: dissociation of H2, and formation of titanium subfluorides on the TiN surface.

The Preparation of Ferronickel Powder from Nickel-Contained Sodium Jarosite Residue

2011 ◽  
Vol 396-398 ◽  
pp. 536-542
Author(s):  
Rui Ren ◽  
Shu Ping Zheng ◽  
Qian Zhang
Keyword(s):  
Hydrogen Reduction ◽  
Reduction Process ◽  
Decomposition Temperature ◽  
Reduction Temperature ◽  
Liquid Ratio ◽  
Percent Reduction ◽  
Alkaline Decomposition ◽  
Reduced Products ◽  
Naoh Solution ◽  
Solid Liquid

nickel and iron was recovered as ferronickel from sodium jarosite residue containing nickel, the processes include alkaline decomposing residue, hydrogen reducing precipitations produced in alkaline decomposition process and magnetic separating reduced precipitations. The effects of alkaline decomposition temperature, the concentration of NaOH solution and solid/liquid ratio on the process of alkaline decomposing residue were examined. Meanwhile, the influence of hydrogen reduction temperature on the reduced products was studied, too. The results shown the natrojarosite in residue can be near completely decomposed to form hydroxide precipitations in the process of alkaline decomposition. In the process of hydrogen reduction, the rise of reduction temperature can increase the percent reduction for both nickel and iron in reduced results. But it is easier to reduce nickel than to reduce iron at the range of 750°C-950°C. When hydrogen reduction temperature was 950 °C, the percent reduction for nickel and iron in hydrogen reduction process was 95.81% and 94.4%, respectively. XRD tests indicated, except for ferronickel, there were still some impurities such as barium sulfate and barium oxide in reduced product. SEM test indicated the particles of precipitations will become fused together during hydrogen reduction process, so it is difficult to magnetic separate ferronickel purely from reduced results. The content of nickel and iron in magnetic separating product was only 11.64% and 62.40%.

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