scholarly journals Effect of Nitrogen Pressure on the Structure of Cr-N, Ta-N, Mo-N, and W-N Nanocrystals Synthesized by Arc Discharge

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Longhai Shen ◽  
Nan Wang
Keyword(s):  
Experimental Observation ◽  
Evaporation Rate ◽  
Arc Discharge ◽  
Nitrogen Pressure ◽  
Cubic Phase ◽  
Discharge Process ◽  
Low Nitrogen

The effect of nitrogen pressure on the structure of Ta-N, Cr-N, Mo-N, and W-N nanocrystals formed in arc discharge process was investigated. At the nitrogen pressure of5~20 kPa, the pure cubic-phase TaN and CrN nanocrystals were formed, whereas pure cubic phase of Mo2N and W2N cannot be obtained. A little of metal Mo and a mass of metal W were mixed with the products of Mo2N and W2N, respectively. At the nitrogen pressure of30~50 kPa, subnitride Ta2N and Cr2N and metal Cr were gradually formed in the product; furthermore, the proportion of metal Mo and W increased in the product of Mo2N and W2N, respectively. It indicated that the low nitrogen pressure makes cubic mononitride formation favorable. We explain this experimental observation in terms of the evaporation rate of anode metal and the ionization of nitrogen.

Synthesis and Characterization of FeCoNiAl Nanocapsules by Plasma arc Discharge Process

2005 ◽  
Vol 20 (9) ◽  
pp. 2534-2543 ◽  
Author(s):  
Dian-Yu Geng ◽  
Woo-Young Park ◽  
Jin-Chun Kim ◽  
Ji-Hun Yu ◽  
Chul-Jin Choi ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Transition Metal ◽  
Surface Composition ◽  
Arc Discharge ◽  
Binding Energies ◽  
The Body ◽  
Cubic Phase ◽  
Discharge Process ◽  
Plasma Arc ◽  
Plasma Arc Discharge

A series of magnetic FeCoNiAl nanocapsules was synthesized by the plasma arc discharge method; the targets of Fe, Co, Ni, and Al powders were changed with varying compositions. The compositions of the nanocapsules were found to be quite different from those of the corresponding targets; the relative amount of Al (or Ni, Co) to Fe was increased (or decreased). Structures, particles sizes, composition, surface composition, magnetic properties, and thermal stability of the nanocapsules were investigated. The saturation magnetization Ms = 106.8 emu/g and coercive force iHc = 367 Oe were achieved for the nanocapsules with the Fe62.5Co21Ni13Al2.5 target. In the FeCoNiAl nanocapsules, the binding energies of Fe, Co, and Ni were different from those of the metals Fe, Co, and Ni. The binding energies of Fe2p3/2 and Fe2p1/2 of the nanocapsules were 708.2 and 721.3 eV, respectively. The four-layer structure was proposed to give a clear statement of how the composition and phase varied radially in the nanocapsules. The major contents of the four layers—i.e., the outer shell, the inner shell, the outer core and the inner core—were amorphous alumina, crystalline alumina, transition metal oxides, and transition metal alloy, respectively. The compositions, structures, particle size, and grain size of the nanocapsules all affect their magnetic properties. In the FeCoNiAl nanocapsules, the greater th amount of the body-centered-cubic phase, the stronger the ferromagnetic magnetic properties.

scholarly journals Synthesis of Lithium Phosphorus Oxynitride (LiPON) Thin Films by Li3PO4 Anodic Evaporation in Nitrogen Plasma of a Low-Pressure Arc Discharge

Membranes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 40
Author(s):  
Nikolay Gavrilov ◽  
Alexander Kamenetskikh ◽  
Petr Tretnikov ◽  
Alexey Nikonov ◽  
Leonid Sinelnikov ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Evaporation Rate ◽  
Arc Discharge ◽  
Threshold Value ◽  
Nitrogen Pressure ◽  
Nitrogen Plasma ◽  
Plasma Radiation ◽  
Arc Current ◽  
Lithium Phosphorus Oxynitride ◽  
Plasma Stabilization

Thin amorphous films of LiPON solid electrolyte were prepared by anodic evaporation of lithium orthophosphate Li3PO4 in an arc discharge with a self-heating hollow cathode at a nitrogen pressure of 1 Pa. Distribution of the arc current between two electrodes having an anode potential provided independent control of the evaporation rate of Li3PO4 and the density of nitrogen plasma. Stabilization of the evaporation rate was achieved using a crucible with multi-aperture cover having floating potential. The existence of a threshold value of discharge current (40 A) has been established, which, upon reaching ionic conductivity over 10−8 S/cm, appears in the films. Probe diagnostics of discharge plasma were carried out. It has been shown that heating the films during deposition by plasma radiation to a temperature of 200 °C is not an impediment to achieving high ionic conductivity of the films. Dense uniform films of LiPON thickness 1 mm with ionic conductivity up to 1 × 10−6 S/cm at a deposition rate of 4 nm/min are obtained.

Combustion Synthesis of Si3N4 from Si/NH4Cl at Low Nitrogen Pressure

2008 ◽  
Vol 368-372 ◽  
pp. 1767-1770 ◽  
Author(s):  
Yi Xiang Chen ◽  
Jiang Tao Li ◽  
Zhi Ming Lin ◽  
Guang Hua Liu ◽  
S.L. Yang ◽  
...  
Keyword(s):  
Combustion Synthesis ◽  
Combustion Temperature ◽  
Profile Analysis ◽  
Combustion Velocity ◽  
Nitrogen Pressure ◽  
Analysis Method ◽  
Α Phase ◽  
Steady Combustion ◽  
Combustion Wave Velocity ◽  
Low Nitrogen

Combustion synthesis (CS) of Si3N4 was accomplished by using as-milled Si/NH4Cl as reactants at low nitrogen pressure. The additive of NH4Cl decreased the combustion temperature and promoted the Si nitridation. Full nitridation of Si was achieved by burning Si in pressurized nitrogen with 10 ~ 25 wt. % NH4Cl as additives while no Si3N4 diluent added. The maximum combustion temperature (Tc), the combustion velocity (u) together with the α-Si3N4 content and mean particle size (d50) of the powder products were found to be great dependent on the NH4Cl content added in the reactants. Fine Si3N4 powder products with α-phase content up to 85 wt. % were obtained via steady combustion mode. A mathematical approach named combustion wave velocity methods for the analysis of temperature profiles in CS was proposed and the reaction kinetics was discussed. The apparent activation energy calculated according to the temperature profile analysis method is 29.7 kJ/mol, which agrees well with the corresponding low temperature nitriding combustion of Si.

scholarly journals Nonlinear Hydraulic Pressure Response of an Improved Fiber Tip Interferometric High-Pressure Sensor

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2548
Author(s):  
Wei Huang ◽  
Zhe Zhang ◽  
Jun He ◽  
Bin Du ◽  
Changrui Liao ◽  
...  
Keyword(s):  
High Pressure ◽  
Nonlinear Response ◽  
Arc Discharge ◽  
High Sensitivity ◽  
Measurement Range ◽  
Hydraulic Pressure ◽  
Discharge Process ◽  
Pressure Sensitivity ◽  
Diaphragm Thickness ◽  
Order Of Magnitude

We demonstrate a silica diaphragm-based fiber tip Fabry–Perot interferometer (FPI) for high-pressure (40 MPa) sensing. By using a fiber tip polishing technique, the thickness of the silica diaphragm could be precisely controlled and the pressure sensitivity of the fabricated FPI sensor was enhanced significantly by reducing the diaphragm thickness; however, the relationship between the pressure sensitivity and diaphragm thickness is not linear. A high sensitivity of −1.436 nm/MPa and a linearity of 0.99124 in hydraulic pressure range of 0 to 40 MPa were demonstrated for a sensor with a diaphragm thickness of 4.63 μm. The achieved sensitivity was about one order of magnitude higher than the previous results reported on similar fiber tip FPI sensors in the same pressure measurement range. Sensors with a thinner silica diaphragm (i.e., 4.01 and 2.09 μm) rendered further increased hydraulic pressure sensitivity, but yield a significant nonlinear response. Two geometric models and a finite element method (FEM) were carried out to explain the nonlinear response. The simulation results indicated the formation of cambered internal silica surface during the arc discharge process in the fiber tip FPI sensor fabrication.

Dynamic variation of arc discharge and its effect on corrosion direction under current-carrying sliding

2018 ◽  
Vol 233 (3) ◽  
pp. 380-392 ◽  
Author(s):  
Chaoyong Deng ◽  
Jian Yin ◽  
Hongbo Zhang ◽  
Xiang Xiong ◽  
Pei Wang ◽  
...  
Keyword(s):  
Friction Surface ◽  
High Speed ◽  
Friction And Wear ◽  
Arc Discharge ◽  
Capture Rate ◽  
Three Dimensional ◽  
Discharge Process ◽  
Friction Process ◽  
Large Margin ◽  
Dynamic Variation

Current-carrying sliding tests were performed on an HST-100 high-speed multifunction friction and wear tester. Cf/Cu/C composite was used as the pin, and commercial QCr0.5 was employed as the disk. Sliding tests were carried out at a speed of 30 m/s and a load of 70 N under 25 A, 50 A, 75 A, and 100 A, respectively. Light intensity was collected by a photodiode, and the arc discharge process was recorded by a high-speed camera (HX-5) with a capture rate of 20,000 fp/s. The worn surfaces were characterized by a Nova NanoSEM230 scanning electron microscope and a NANO Focus AG three-dimensional topography instrument. The result indicates that arc discharge occurs randomly, both temporally and spatially, as long as the condition is suitable and occurs more at the beginning and end of the friction process. The arc moves constantly along the friction direction to the outlet. Compared to the inlet, the erosion of the outlet is considerably worse. This finding indicates the arc is moving towards the outlet and grows by a large margin when it leaves the friction surface at the outlet end.

Seamless aqueous arc discharge process for producing graphitic carbon nanostructures

Carbon ◽  
2017 ◽  
Vol 120 ◽  
pp. 83-88 ◽  
Author(s):  
Sejung Kim ◽  
Youngjun Song ◽  
Michael J. Heller
Keyword(s):  
Carbon Nanostructures ◽  
Arc Discharge ◽  
Graphitic Carbon ◽  
Discharge Process

As-Quenched ARC Products By bulse - Discharge

2000 ◽  
Vol 6 (S2) ◽  
pp. 54-55
Author(s):  
Y. Murooka ◽  
Y. Maede ◽  
M. Ozaki ◽  
M. Hibino
Keyword(s):  
Steady State ◽  
Arc Discharge ◽  
Electron Bombardment ◽  
Discharge Process ◽  
Arc Plasma ◽  
Growth Mechanisms ◽  
Physical Processes ◽  
Small Current ◽  
Short Time ◽  
Non Equilibrium

Since their discovery, steady state arc discharge has been used for fullerenes and nanotubes production. Unfortunately this method intrinsically made it difficult to understand their growth mechanisms since the discharge included many complicated physical processes and the growth happened in the non-equilibrium arc plasma. Processes such as heating of the cathode by cation bombardment, emission of thermal electrons, and heating of the anode by electron bombardment are important in order to follow the mechanism, but it is difficult to study them separately. In the present work, however, it was shown that a pulse-arc discharge with a small current for a short time could simplify the discharge process and provide as-quenched arc products, which should be useful to understand the mechanisms.Short discharges with a small current were performed on the pulse-arc system, which was developed by the authors.

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