• Journal of the Korean Ceramic Society
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• v.34 no.3
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• pp.273-273
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• 1997

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.25.1-25
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• 2002

• Korean Journal of Materials Research
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• v.24 no.10
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• pp.526-531
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• 2014

Thermal shock resistance property has recently been considered to be one of the most important basic properties, in the same way that the transverse-rupture property is important for sintered hard materials such as ceramics, cemented carbides, and cermets. Attempts were made to evaluate the thermal shock resistance property of 10 vol% TaC added Ti(C,N)-Ni cermets using the infrared radiation heating method. The method uses a thin circular disk that is heated by infrared rays in the central area with a constant heat flux. The technique makes it possible to evaluate the thermal shock strength (Tss) and thermal shock fracture toughness (Tsf) directly from the electric powder charge and the time of fracture, despite the fact that Tss and Tsf consist of the thermal properties of the material tested. Tsf can be measured for a specimen with an edge notch, while Tss cannot be measured for specimens without such a notch. It was thought, however, that Tsf might depend on the radius of curvature of the edge notch. Using the Tsf data, Tss was calculated using a consideration of the stress concentration. The thermal shock resistance property of 10 vol% TaC added Ti(C,N)-Ni cermet increased with increases in the content of nitrogen and Ni. As a result, it was considered that Tss could be applied to an evaluation of the thermal shock resistance of cermets.

• Journal of the Korean Vacuum Society
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• v.3 no.2
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• pp.190-197
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• 1994

본 연구에서는 DC magnetron 스퍼터링법을 이용하여 고정밀, 고저항 저항체 박막으로 TaNx film을 제조하였을 때 형성될 수 있는 화합물 중 TaN0.1, TaN0.8과 TaN 박막의 Rs와 TCR특성을 평가하 고 film층의 우선방향성을 XRD를 이용하여 판명한 뒤 저항체의 Rs와 TCR에 미치는 영향을 조사하였 다. TaN0.1 박막이 35$\Omega$/$\square$의 면저항값과 안정된 TCR값을 나타내는 것을 알수 있었다. 두께50~200nm 의 TaN0.1과 Alumina 기판 사이에 정(+)의 TCR을 갖는 약 50nm의 Cr층을 증착하였을 때 Rs는 180$\Omega$/ $\square$ 과 TCR는 20ppm/$^{\circ}C$인 적층박막을 제조할 수 있었다. TaN0.1, TaN0.8 과 TaN 시편에서 화합물 형성 에 따른 Ta의 결합에너지를 ESCA를 이용하여 조사하였다. 이상의 연구결과로부터 TaN0.1 film이 TaNfilm 보다 고정밀, 고저항 박막 저항체 제조에 있어 우수한 전기저항 특성을 가지며 Cr 중간층 형성 으로 TCR이 $\pm$ppm/$^{\circ}C$정도로 안정된 고정밀 다층 저항체 박막을 형성할 수 있었다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.202-208
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• 2003

This study carried out a cutting experiment on Duralumin A16061-76, which is light but strong and highly anticorrosive, so recently popular as a lightweight material, by changing cutting conditions and alternating 4 insert tips, and examined the effect of each insert tip on cutting force at certain cutting conditions, the measurements of the coarseness of processed surfaces roughness, and the chip workability. The 1311owing conclusions were drawn from the results. Cutting force for cutting tool is when insert tips were alternated at each cutting condition, the cutting force of cutting tools was highest then CBN tools were use(1 next by Ceramic tools, Cermet tools, and WC tools. Therefore, WC tools are considered most suitable for cutting Duralumin A16061-T6. Surface roughness as for the coarseness of surfaces according to insert tips applied to Duralumin A16061-T6 under the cutting condition of depth of cut below 1mm, feed rate below 0.24mm/rev and cutting speed over 100m/min the coarseness of material surface roghness appeared to be finest when WC tools were used, next by Ceramic tools, Cermet tools, and CBN tools.

• Journal of the Korean Ceramic Society
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• v.45 no.12
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• pp.807-814
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• 2008

The Cu-Ni-YSZ cermet anodes for direct use of methane in solid oxide fuel cells have been fabricated by electroplating Cu into the porous Ni-YSZ cermet anode. The uniform distribution of Cu in the Ni-YSZ anode could be obtained via pulse electroplating in the aqueous solution mixture of $CuSO_4{\cdot}5H_{2}O$ and ${H_2}{SO_4}$ for 30 min with 0.05 A of average applied current. The power density ($0.17\;Wcm^{-2}$) of a single cell with a Cu-Ni-YSZ anode was shown to be slightly lower in methane at $700^{\circ}C$, compared with the power density ($0.28\;Wcm^{-2}$) of a single cell with a Ni-YSZ anode. However, the performance of the Ni-YSZ anode-supported single cell was abruptly degraded over 21 h because of carbon deposition, whereas the Cu-Ni-YSZ anode-supported single cell showed the enhanced durability upto 52 h.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.357-361
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• 2014

An Ni-Fe/YSZ core-shell structured anode for uniform microstructure and catalytic activity was synthesized. Flat tubular segmented-in-series solid oxide fuel cell-stacks were prepared by decalcomania method using synthesized anode powder. The Ni-Fe/YSZ core-shell anode exhibited better electrical conductivity than a commercially available Ni-YSZ cermet anode. Also power output increased by 1.3 times with a higher open circuit voltage. These results can be attributed to the uniformly distributed Ni particles in the YSZ framework. The impedance spectra of a Ni-Fe/YSZ core-shell anode showed comparable reduced ohmic resistance similar to those of the commercially available Ni-YSZ cermet anodes.

• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.764-767
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• 2006

Ni/YSZ $(Y_2O_3-stabilized\;ZrO_2)$ composite as an electrode component for High Temperature Electrolysis (HTE) was fabricated by mechanical alloying method using Ni and YSZ powders. Characterization of the synthesized composite was investigated with various analysis tools, including XRD, SEM and PSA, and a self-supporting planar unit cell prepared with the Ni/YSZ composite was prepared to study the electrochemical reactions for the production of hydrogen. The Ni/YSZ cermet is composed of crystalline Ni and YSZ, in a sub-micro scale, and has an even distribution without aggregated particles. In addition, under an electrochemical reaction, the unit cell showed an $H_2$ evolution rate from steam of 14 Nml/min and $600mA/cm^2$ of current density at the electrode.

• Transactions of the Korean hydrogen and new energy society
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• v.16 no.4
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• pp.372-378
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• 2005

Ni/YSZ ($Y_2O_3$-stabilized $ZrO_2$) composite powder for a cathode material in high temperature electrolysis(HTE) was synthesized by a mechanical alloying method with Ni and YSZ powder. Microstructure of the composite and cell thickness for HTE reaction has been analyzed with various techniques of XRD, SEM to investigate effects of fabrication conditions. Employing the composite material, furthermore, the unit cell for HTE has been studied to evolve hydrogen from water. XRD patterns showed that the composites after wet mechanical alloying were composed of respective nano-sized crystalline Ni and YSZ. While ethanol as additive for mechanical alloying increased to $20\;{\mu}m$ of average particle size of the composites, alpha-terpineol effectively decreased to sub-micro size of that. This study has been found out the evolution of hydrogen by HTE reaction employing the fabricated cathode material, showing 1.4 ml/min of $H_2$ generation rate as increasing $20\;{\mu}m$ of cathode thickness.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.1055-1062
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• 1988

The characteristics of tool wear and the machinability in cutting of GFRP have been studied. The wear behavior of carbide insert tools(P20, M10, K10) and Cermet in TiC grade was studied by turning of changing the cutting condition. Machinability could be estimated as the following empirical formula, CT$^{n}$ =W The main results obtained are as follows: (1) Dependence of rate of tool wear on cutting speed; with increases of cutting speed, the rate of tool wear initially increases gradually(1st range), then it increases proportionally to cutting speed(2nd range), and finally the rate is constant(3rd range). (2) When the contact length has a main, effect on tool wear, the cutting speed does nit affect the tool wear. On the contrary, the cutting speed has a main effect on tool wear, the contact length does not affect the tool wear. (3) The order of machinability is K10, M10, P20 and Cermet in TiC grade.