• Title/Summary/Keyword: Plasma resistance

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Study on the heat-resistance characteristic for PLS(Plasma Light System) (PLS(Plasma Light System)의 내열방사 특성 연구)

  • Shin, Sang-Wuk;Lee, Se-Hyun;Cho, Mee-Ryoung;Lim, Jong-Min;Hwang, Myung-Keun
    • Proceedings of the KIEE Conference
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    • 2004.11a
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    • pp.293-295
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    • 2004
  • PLS(Plasma Light System) is one of the electrodeless lamp discharged by micro wave. In this new lamp has high efficacy and CRI(Color Rendering Index). It is mainly composed of microwave part and optical part. Microwave parts consist of magnetron, wave-guide and cavity-mesh, while optical parts consist of bulb, mirror and reflector. In this paper, we studied experimentally the heat-resistance and temperature distribution characteristics of bulb in PLS.

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Initial Performance Degradation of Hydrogen-Fueled Ceramic Fuel Cell with Plasma-Enhanced Atomic Layer-Deposited Ultra-Thin Electrolyte (플라즈마 원자층증착 초박막전해질 수소 세라믹연료전지의 초기성능 저하)

  • JI, SANGHOON
    • Transactions of the Korean hydrogen and new energy society
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    • v.32 no.5
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    • pp.340-346
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    • 2021
  • The initial electrochemical performance of ceramic fuel cell with thin-film electrolyte fabricated by plasma-enhanced atomic layer deposition method was evaluated in terms of peak power density ratio, open circuit voltage ratio, and activation/ohmic resistance ratios at 500℃. Hydrogen and air were used as anode fuel and cathode fuel, respectively. The peak power density ratio reduced as ~52% for 30 min, which continually decreased as time increased but degradation rate gradually decreased. The open circuit voltage ratio decreased with respect time; however, its behavior was evidently different from the reduction behavior of the peak power density. The activation resistance ratio increased as ~127% for 30 min, which was almost similar with the reduction behavior of the peak power density ratio.

Characterization of AZO Thin Film by Plasma Surface Treatment (플라즈마 표면 처리에 따른 AZO 박막의 특성 변화)

  • Woo, Jong-Chang;Kim, Gwan-Ha
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.32 no.2
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    • pp.147-150
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    • 2019
  • There is a need for the development of transparent conductive materials that are economical and environmentally friendly with exhibit low resistivity and high transmittance in the visible spectrum. In this study, the deposition rate and uniformity of Al-doped ZnO-thin films were improved by changing the Z-motion of the sputtering system. The deposition rate and the uniformity were determined to be 3.44 nm/min and 1.23%, respectively, under the 10 mm Z-motion condition. During $O_2$ plasma treatment, the intrusion-type metal elements in the thin film were reduced, which contributed to an oxygen vacancy reduction in addition to structural stabilization. Moreover, the sheet resistance was more easily saturated.

Effect of Argon Plasma Treatment On Silver Nanowires

  • Tran, Vo Thi Bao;Choi, Dooho
    • Journal of the Microelectronics and Packaging Society
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    • v.28 no.1
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    • pp.73-77
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    • 2021
  • In this study, we report on the effects of argon plasma treatment on Ag nanowires by varying the power and duration. Sheet resistance was found to be significantly reduced to 10 ohm/sq. relative to the value of 21 ohm/sq. for the pristine sample. Such a reduction was found to be associated with welded junctions between Ag nanowires, which results in enhanced current flow. With the optimized plasma treatment conditions, the maximum and average transmittance were 76.8% and 71%, respectively. Finally, we fabricated transparent heating devices based on the methodology, which exhibited superior heating capability.

Mechanical Properties and Corrosion Resistance of Plasma Electrolytic Oxidation Coatings on AZ31 Magnesium Alloy

  • Park, Jae Seon;Jung, Hwa Chul;Shin, Kwang Seon
    • Corrosion Science and Technology
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    • v.5 no.2
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    • pp.77-83
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    • 2006
  • The plasma electrolytic oxidation (PEO) process is a relatively new surface treatment technique that produces a chemically stable and environment-friendly electrolytic coating that can be applied to all types of magnesium alloys. In this study, the characteristics of oxide film were examined after coating the extruded AZ31 alloy through the PEO process. Hard ceramic coatings were obtained on the AZ31 alloy by changing the coating time from 10min to 60min. The morphologies of the surface and the cross-section of the PEO coatings were examined by scanning electron microscopy and optical microscopy, and the thickness of the coating was measured. The X-ray diffraction pattern of the coating shows that the coated layer consists mainly of the MgO and $Mg_2SiO_4$ phases after the oxidation reaction. The hardness of the coated AZ31 alloy increased with increasing coating time. In addition, the corrosion rates of the coated and uncoated AZ31 alloys were examined by salt spray tests according to ASTM B 117 and the results show that the corrosion resistance of the coated AZ31 alloy was superior to that of the un-coated AZ31 alloy.

Effect of Sodium Aluminate Concentration in Electrolyte on the Properties of Anodic Films Formed on AZ31 Mg Alloy by Plasma Electrolytic Oxidation (AZ31 마그네슘 합금의 플라즈마 전해 산화에서 Sodium Aluminate 농도가 산화막 특성에 미치는 영향)

  • Lee, Jong-Seok;Baek, Hong-Gu;Kim, Sung-Wan
    • Journal of the Korean Society for Heat Treatment
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    • v.25 no.5
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    • pp.227-232
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    • 2012
  • Magnesium alloy have good physical properties such as good castability, good vibration absorption, high strength/weight ratios. Despite the desirable properties, the poor resistance of Mg alloy impedes their use in many various applications. Therefore, magnesium alloy require surface treatment to improve hardness, corrosion and wear resistance. Plasma Electrolytic Oxidation (PEO) is one the surface treatment methods to form oxide layer on Mg alloy in alkali electrolyte. In comparison with Anodizing, there is environmental process having higher hardness and faster deposition rate. In this study, the characteristics of oxide film were examined after coating the AZ31 Mg alloy through the PEO process. We changed concentration of sodium aluminate into $K_2ZrF_6$, KF base electrolyte. The morphologies of the coating layer were characterized by using scanning electron microscopy (SEM). Corrosion resistance also investigated by potentiodynamic polarization analysis. As a result, propertiy of oxide layer were changed by concentration of sodium aluminate. Increasing with concentration of sodium aluminate in electrolyte, the oxidation layer was denser and the pore size was smaller on the surface.

Oxidation Resistance of SPS (Spark Plasma Sintering) Sintered β-FeSi2Bodies at High Temperature (방전플라즈마 소결법으로 제작한 β-FeSi2 소결체의 고온 내산화성)

  • Chang, Se-Hun;Hong, Ji-Min;Oh, Ik-Hyun
    • Korean Journal of Materials Research
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    • v.17 no.3
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    • pp.132-136
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    • 2007
  • Oxidation resistance of sintered ${\beta}-FeSi_{2}$ was investigated at intermediate temperature range in air atmosphere. Fully dense and porous bodies of ${\beta}-FeSi_{2}$ samples were fabricated by using the Spark Plasma Sintering (SPS). They were annealed at $900^{\circ}C$ for 5days to obtain ${\beta}-FeSi_{2}$ phase. The bulk samples were oxidized at $800,\;900\;and\;950^{\circ}C$ in air atmosphere. The high temperature oxidation tests reveal that amorphous $SiO_{2}$ layer, similar to Si was formed and grew parabolically on ${\beta}-FeSi_{2}$. Accelerated oxidation is not observed as well as cracks and grain boundary oxidation. Granular ${\varepsilon}-FeSi$ was developed below the oxide layer as a result of oxidation of ${\beta}-FeSi_{2}$. Oxidation resistance of sintered ${\beta}-FeSi_{2}$ was excellent for high-temperature thermoelectric application.

A comparative study of electrochemical properties in CrN films prepared by inductively coupled plasma magnetron sputtering (유도결합형 플라즈마 마그네트론 스피터로 제작된 CrN 코팅막의 전기화학적 물성 비교 연구)

  • Jang, Hoon;Chun, Sung-Yong
    • Journal of the Korean institute of surface engineering
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    • v.55 no.2
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    • pp.70-76
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    • 2022
  • In this paper, we compared the properties of the chromium nitride (CrN) films prepared by inductively coupled plasma magnetron sputtering (ICPMS). As a comparison, CrN film prepared by a direct current magnetron sputtering (dcMS) is also studied. The crystal structure, surface and cross-sectional microstructure and composite properties of the as-deposited CrN films are compared by x-ray diffraction, field emission scanning electron microscopy, nanoindentation tester and corrosion resistance tester, respectively. It is found that the as-deposited CrN films by ICPMS grew preferentially on (200) plane when compared with that by dcMS on (111) plane. As a result, the films deposited by ICPMS have a very compact microstructure with high hardness: the nanoindentation hardness reached 19.8 GPa and 13.5 GPa by dcMS, respectively. Besides, the residual stress of CrN films prepared by ICPMS is also relatively large. After measuring the corrosion resistance, the corrosion current of films prepared by ICPMS was three order of magnitude smaller than that of CrN films deposited by dcMS.

Plasma nitriding on chromium electrodeposit

  • Wang Liang;K.S. Nam;Kim, D.;Kim, M.;S.C. Kwon
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2001.11a
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    • pp.29-30
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    • 2001
  • This paper presents some results of plasma nitriding on hard chromium deposit. The substrates were C45 steel and $30~50{\;}\mu\textrm{m}$ of chromium deposit by electroplating was formed. Plasma nitriding was carried out in a plasma nitriding system with $95NH_3{\;}+{\;}SCH_4$ atmosphere at the pressure about 600 Pa and different temperature from $450^{\circ}C{\;}to{\;}720^{\circ}C$ for various time. Optical microscopy and X-ray diffraction were used to evaluate the characteristics of surface nitride layer formed by nitrogen diffusion from plasma atmosphere inward iCr coating and interface carbide layer formed by carbon diffusion from substrate outward Cr coating. The microhardness was measured using microhareness tester at the load of 100 gf. Corrosion resistance was evaluated using the potentiodynamic measurement in 3.5% NaG solution. A saturated calomel electrode (SiCE) was used as the reference electrode. Fig.1 shows the typical microstructures of top surface and cross-section for nitrided and unnitrided samples. Aaer plasma nitriding a sandwich structure was formed consisting of surface nitride layer, center chromium layer and interface carbide layer. The thickness of nitride and carbide layers was increased with the increase of processing temperature and time. Hardness reached about 1000Hv after nitriding while 900Hv for unnitrided hard chromium deposit. X-ray diffraction indicated that surface nitrided layer was a mixture of $Cr_2N$ and CrN at low temperature and erN at high temperature (Fig.2). Anodic polarization curves showed that plasma nitriding can greatly improve the corrosion resistance of chromium e1ectrodeposit. After plasma nitriding, the corrosion potential moved to noble direction and passive current density was lower by 1 to 4 orders of magnitude compared with chromium deposit(Fig.3).

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Design and fabrication of an optimized Rogowski coil for plasma current sensing and the operation confidence of Alvand tokamak

  • Eydan, Anna;Shirani, Babak;Sadeghi, Yahya;Asgarian, Mohammad Ali;Noori, Ehsanollah
    • Nuclear Engineering and Technology
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    • v.52 no.11
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    • pp.2535-2542
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    • 2020
  • To understand the fundamental parameters of Alvand tokamak, A Rogowski coil with an active integrator was designed and constructed. Considering the characteristics of the Alvand tokamak, the structural and electrical parameters affecting the sensor function, were designed. Calibration was performed directly in the presence of plasma. The sensor has a high resistance against interference of external magnetic fields. Plasma current was measured in various experiments. Based on the plasma current profile and loop voltage signal, the time evolution of plasma discharge was investigated and plasma behavior was analyzed. Alvand tokamak discharge was divided into several regions that represents different physical phenomena in the plasma. During the plasma discharge time, plasma had significant changes and its characteristic was not uniform. To understand the plasma behavior in each of the phases, the Rogowski sensor should have sufficient time resolution. The Rogowski sensor with a frequency up to 15 kHz was appropriate for this purpose.