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Charging, movement and lifetime characteristics of spherical dust grains generated in magnetic fusion devices are discussed. A universal charging equation of the dust grain is given. The simulation results show that the charge quantity of the dust grain changes along with the ratio of electron and ion temperature, and decreases due to secondary electron emission, the charging relaxation time of dust...
Development of Hall thrusters for nano, small and low power satellites below 100 W is expected. In lowering Hall thruster power, the cylindrical type Hall thruster is more advantage than conventional coaxial-type Hall thrusters. In this study, a very low power cylindrical Hall thruster for nano-satellite “PROITERES-3” under development in Osaka Institute of Technology was designed, and the thruster...
Several advanced plasma propulsion designs have been developed and characterized at IRS in the past years. Among them are the hybrid thruster TIHTUS, the steady state applied-field thrusters AF-MPD ZT1 and ZT2 and advanced iMPD designs. These concepts show promising potential for future missions. The paper will discuss the designs and their operational features.In addition, more advanced systems are...
The micro-Newton thrust generation was observed through low-power continuous wave laser and aluminum foil interaction without any remarkable ablation of the target surface. To evaluate the thrust characteristics, a torsion balance thrust stand capable for the measurement of the thrust level down to micro-Newton ranges was developed. In the case of an aluminum foil target with 12.5 micrometer thickness,...
The conversion of biogas like mixtures of methane and carbon dioxide was studied in a plug flow reactor with a dielectric barrier discharge. A 13.56 MHz power supply generated the atmospheric plasma discharge. Studied concentration of methane ranged from 0 to 100%, with missing part filled up with carbon dioxide. This mixture was diluted with helium to 2.5% with small part of the product stream monitored...
The Eighth International Symposium on Applied Plasma Science (ISAPS ’11) was held at the Yumoto Fujiya Hotel, in Hakone, Japan on September 26 through 30, 2011. The selected papers presented at ISAPS ’11 were written after the symposium. Those were peer refereed and are compiled in this special issue of Vacuum.
At Gifu University, to understand unsteady operation phenomena including plasma generation and exhaust processes on a coaxial pulsed plasma thruster (PPT), the luminescence behavior has been studied. In this study, spatial velocity distributions were compared with the results of electrostatic measurement and high-speed photography, and the applicability of a photosensor system to the plume measurements...
The thermal shock behavior and microstructural investigation of CoNiCrAlYSi coatings applied by Low Vacuum Plasma Spray (LVPS) and High-Velocity Oxy Fuel (HVOF) techniques on the Ni-base superalloy IN738LC were examined. Thermal shock resistance was investigated by forced water quenching of coated samples from high temperature (1100°C) to room temperature. Thermal shock life time of coatings were...
Recent developments in silver nanorods, fabricated by oblique-angle deposition (OAD) technique, have provide a great ability to produce high gain enhancement, reproducible, uniform response, and low-cost surface-enhanced Raman scattering (SERS) substrates. However, shelf-time stability, while not well studied, of this type of the substrates has been a primary concern for future SERS applications....
Alumina-titania coatings are used where a high wear and oxidation resistances are required. These coatings are usually deposited by thermal spraying. The use of nanoparticles as feeding powders can lead to improved properties if some technological problems are solved. The small size of the nanoparticles makes necessary to prepare agglomerates able to be sprayed by conventional equipments. The plasma...
Layers of TiN/TiO x N y were coated onto 316L stainless steel substrates by plasma ion sputtering technique. The layers were sputtered with the arc current of 2.5 A and with an acceleration voltage of 1000 V, for a sputtering time of 120 min. The XPS survey spectra on the surface of coatings showed the characteristic Ti2p, N1s and O1s peaks at the corresponding binding energies. X-ray...
Numerical simulation of in-flight particles in thermal plasma jet is one of the most important research fields. It has been used to analyze the influence of spray parameters on jet characteristics and to improve the quality of coating during plasma spraying. In this study, in-flight behavior of a group of lanthanum zirconate (La 2 Zr 2 O 7 ) particles with different diameters...
To perform high-quality welding, the heat input from the arc to the base metal is controlled. However, an anode jet sometimes occurs. In such cases, control is difficult and weld defects occur. This study elucidates how anode jet generation is affected by the radial current density distribution for maintaining the current continuity. The anode jet starts to occur at 15–20 mm of interelectrode distance...
For use as a diaphragm in an environmental-cell transmission electron microscope (E-cell TEM) system, amorphous silicon carbon nitride (a-SiCN) films were applied to a Cu grid with 100-μm-diameter holes by plasma-enhanced chemical vapor deposition. The applied films were characterized by X-ray photoelectron spectroscopy and TEM and their capacity to resist pressure were measured. The films were amorphous...
The overlay coatings were corrosion tested in a 3% aqueous NaCl solution. The metallic glasses Ni 60 Nb 20 Zr 20 coating plasma sprayed at 250 A arc current and the 45–50 mm spraying distance revealed the outstanding corrosion resistance and outperformed pad welded coatings. For all sprayed metallic glass coatings, the microhardness increased with the rising arc current. The...
Oxidation tests of ZrB 2 –SiC composite were carried out at 1373–1923 K under a low oxygen partial pressure of 57 Pa. By making composite with SiC, ZrB 2 shows good oxidation resistance. The ZrB 2 -15 vol.%SiC composite shows better oxidation resistance at higher temperatures than ZrB 2 -30 vol.%SiC with respect to mass decrease. The SiC depleting is the main cause...
Comparative study of coadsorption and reaction of carbon monoxide and oxygen on bare Mo(110) and borided Mo(110) has been done by means of temperature programmed desorption (TPD), reflection-absorption infrared spectroscopy (RAIRS), X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The B–Mo(110) alloy has been in-situ prepared by depositing of 2 monolayers of atomic boron...
The coefficients of thermal expansion (CTEs) of coatings were necessary to evaluate the thermal stresses of the coated component. In general, the CTEs were measured from the free-standing coatings. It is useful if the CTEs of the coatings are able to be measured from the coating system specimens. The resulting CTE of a coating by the coating system is sensitive to experimental errors when compared...
In this study, AZ31 Mg alloy produced by twin roll casting was coated by a plasma electrolytic oxidation (PEO) in the solution, consisting of Na 2 SiO 3 ·5H 2 O + KOH electrolyte at 0.085 A/cm 2 current density for 15, 30, 45 and 60 min. Thickness of the coated layer, surface morphology, phase structure, hardness, adhesion strength of the layer and wear resistance were...
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