• Carbon letters
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• 제4권2호
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• pp.74-78
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• 2003

Four kinds of plasma blacks were prepared by plasma pyrolysis under various metallic catalysts coated on honeycomb, and investigated the catalytic effect on the characteristics of the plasma blacks prepared under plasma pyrolysis condition. Pt, Pt-Rh, and Pd catalysts were employed as active materials to prepare the plasma blacks. In the experimental range studied, the metallic catalysts influenced on surface area, particle size, surface oxygen content and electrical conductivity of the plasma blacks prepared. It was showed that more dense particle of plasma blacks were prepared under existence of metallic catalysts. Presence of the metallic catalyst reduces the electrical resistivity of plasma blacks due to the decrease in the amount of oxygen functional groups. The highest electrical conductivity of plasma black was observed in the Pt catalyst and then followed by those Pt-Rh, Pd and bare cordierite honeycomb.

• Journal of Welding and Joining
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• 제12권1호
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• pp.94-101
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• 1994

In this study, plasma spraying has been used to produce $TiO_2$ polycrystalline coatings from $TiO_2$ powders. The physical and chemical properties of plasma sprayed $TiO_2$ coatings depend greatly on plasma spraying conditions. The electrical resistivity, oxygen concentration, photocurrent and crystal structure of plasma sprayed $TiO_2$ coating has been studied. The results are as follows: 1. The oxygen loss and electrical conductivity of $TiO_2$ plasma sprayed coatings increased by low pressure and high amount of auxiliary gas, hydrogen in plasma spraying. 2. Oxygen loss increase electrical conductivity, and decrease photocurrent of $TiO_2$ plasma sprayed coatings. 3. Photocurrent of $TiO_2$ plasma sprayed coatings manufactured in atmospheric pressure is higher than that of low pressure.

• 한국추진공학회지
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• 제26권6호
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• pp.1-9
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• 2022

본 연구에서는 현대적 전기식 기폭관의 해석 모델링을 대상으로 실용적 적용이 가능한 금속성 플라즈마 조성비 및 전기전도도 계산모델이 제시되었다. 현 플라즈마 모델은 기폭관 브릿지 전기폭발 현상 시 발생하는 고밀도 플라즈마 영역의 비이상 플라즈마 효과 보정을 포함하였다. 구리 플라즈마를 대상으로 한 계산 결과는 넓은 온도 범위 및 고밀도 영역에서 해당 측정 결과와 전반적으로 잘 일치하여 기폭관 모델링 대상 적용에 적절함을 보여주었다.

• 한국재료학회지
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• 제27권3호
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• pp.155-160
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• 2017

Doped-$LaCrO_3$ perovskites, because of their good electrical conductivity and thermal stability in oxidizing and/or reducing environments, are used in high temperature solid oxide fuel cells as a gas-tight and electrically conductive interconnection layer. In this study, perovskite $(La_{0.8}Ca_{0.2})(Cr_{0.9}Co_{0.1})O_3$ (LCCC) coatings manufactured by atmospheric plasma spraying followed by heat treatment at $1200^{\circ}C$ have been investigated in terms of microstructural defects, gas tightness and electrical conductivity. The plasma-sprayed LCCC coating formed an inhomogeneous layered structure after the successive deposition of fully-melted liquid droplets and/or partially-melted droplets. Micro-sized defects including unfilled pores, intersplat pores and micro-cracks in the plasma-sprayed LCCC coating were connected together and allowed substantial amounts gas to pass through the coating. Subsequent heat treatment at $1200^{\circ}C$ formed a homogeneous granule microstructure with a small number of isolated pores, providing a substantial improvement in the gas-tightness of the LCCC coating. The electrical conductivity of the LCCC coating was consequently enhanced due to the complete elimination of inter-splat pores and micro-cracks, and reached 53 S/cm at $900^{\circ}C$.

• 한국전기전자재료학회논문지
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• 제30권12호
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• pp.788-793
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• 2017

Electrical behaviors of plasma-sprayed $Al_2O_3-TiO_2$ coatings have been investigated in terms of their $TiO_2$ content. On increasing the $TiO_2$ content from 6 to 30 wt%, the DC electrical conductivity increased by several orders of magnitude. From impedance spectroscopy analysis, the total conductivity of the grains and grain boundaries and their respective activation energies were determined without the electrode effects that could impede ionic transfer. An electron transference number was also estimated, ranging between 6.5% and 7.3% for 13 wt% $TiO_2$ and between 0.4% and 0.7% for 30 wt% $TiO_2$ in the coating. Because of the high electronic contribution to the total conductivity, the $Al_2O_3-TiO_2$ coating could be a new candidate material to obtain superior electrical conductivity as well as corrosion and wear resistances.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.402-409
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• 2024

High energy neutron irradiations impact on structural and electrical properties of alumina are studied with particular emphasis on real time in-situ radiation induced conductivity measurement in low flux region. Polycrystalline Al₂O₃ samples are subjected to high energy neutrons produced from D-T neutron generator and Am-Be neutron source. 14 MeV neutrons from D-T generator are chosen to study the role of fast neutron irradiation in the structural modification of samples. Real time in-situ electrical measurement is performed to investigate the change in insulation resistance of Al₂O₃ due to radiation induced conductivity at low flux regime. During neutron irradiation, a significant transient decrease in insulation resistance is observed which recovers relative higher value just after neutron exposure is switched off. XRD results of 14 MeV neutron irradiated samples suggest annealing effect. Impact of relatively low energy neutrons on the structural properties is also studied using Am-Be neutrons. In this case, clustering is observed on the sample surface after prolonged neutron exposure. The structural characterizations of pristine and irradiated Al₂O₃ samples are performed using XRD, SEM, and EDX. The results from these characterizations are analysed and interpreted in the manuscript.

• 한국분말재료학회지
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• 제19권5호
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• pp.343-347
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• 2012

In this study, an oxygen plasma treatment was used as a low temperature debinding method to form a conductive copper feature on a flexible substrate using a direct printing process. To demonstrate this concept, conductive copper patterns were formed on polyimide films using a copper nanoparticle-based paste with polymeric binders and dispersing agents and a screen printing method. Thermal and oxygen plasma treatments were utilized to remove the polymeric vehicle before a sintering of copper nanoparticles. The effect of the debinding methods on the phase, microstructure and electrical conductivity of the screen-printed patterns was systematically investigated by FE-SEM, TGA, XRD and four-point probe analysis. The patterns formed using oxygen plasma debinding showed the well-developed microstructure and the superior electrical conductivity compared with those of using thermal debinding.

• 한국세라믹학회지
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• 제36권11호
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• pp.1205-1210
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• 1999

Ceria based electrolytes were fabricated by a plasma spraying method. The porosity which was crated during the plasma spraying process was infiltrated with Ce0.8Gd0.2O2 sol by ultrasonic treatment and heat treatment at 90$0^{\circ}C$ in order to improve physical and electrical properties. The porosity decreased from 9.8% to 6.5% and gas permeability at 80$0^{\circ}C$ decreased from 16.7$\times$10-3 to 5.7$\times$10-3 cm3(STP)/cm2.s.cmHg as the number of treatment increased 10 cycles. The ionic conductivity was also increased about 30% after 10 times of sealing.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.243-245
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• 1994

We synthesized the conducting diamond-like carbon films using plasma-enhanced chemical vapor deposition and analysized its characteristics. We obtained the metal-containing diamond-like carbon films using $CH_4$, Ar gas and aluminum target. We observed the changes of electrical conductivity, microhardness and surface morphology according to $Ar/CH_4$ ratio, substrate bias and target bias. As the target bias and $Ar/CH_4$ ratio increase and the substrate bias decreases, the electrical conductivity and surface roughness increase. The increase of hardness involves decrease of the electrical conductivity. Metal-containing amorphous hydrogenated carbon films show improved adhesion on metal substrates compared to pure diamond-like carbon films and better electrical conductivity.

• 한국표면공학회지
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• 제45권2호
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• pp.75-80
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• 2012

A sputter-sublimation source was tested for high rate deposition of protective coating of PEMFC(polymer electrolyte membrane fuel cell) with high electrical conductivity and anti-corrosion capability by DC biasing of a metal rod immersed in inductively coupled plasma. A SUS(stainless steel) tube, rod were tested for low thermal conductivity materials and copper for high thermal conductivity ones. At 10 mTorr of Ar ICP(inductively coupled plasma) with 2.4 MHz, 300 W, the surface temperature of a SUS rod reached to $1,289^{\circ}C$ with a dc bias of 150 W (-706 V, 0.21 A) in 2 mins. For 10 min of sputter-sublimation, 0.1 gr of SUS rod was sputter-sublimated which is a good evidence of a high rate deposition source. ICP is used for sputter-sublimation of a target material, for substrate pre-treatment, film quality improvement by high energy particle bombardment and reactive deposition.