• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2002년도 춘계학술강연 및 발표대회
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• pp.65-66
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• 2002

• 한국분말재료학회지
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• 제6권2호
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• pp.139-144
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• 1999

The pure Ti, Ni and carbon powders were reaction milled to synthesize the TiC-Ni based cermet powders with ultrafine microstructures. After milling, the ultrafine TiC or amorphous Ti-Ni phase was obtained, respectively, according to the milling condition. The effects of milling variables on the synthesizing behavior of the powders were investigated in detail. The sintered TiC-Ni based cermet of the reaction milled powders consisted of very fine TiC of 0.2~1.5$\mu$m, as compared with that of a commercial cermet of 3~5$\mu$m. This demonstrates the potenial of reaction milling as an effective processing route for the preparation of cermet materials.

• 한국전기전자재료학회논문지
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• 제12권1호
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• pp.94-102
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• 1999

Ni/CGO cermets were fabricated as the anode for SOFC which uses CGO as the electrolyte. And their electrical conductivity, electrochemical reactivity, and thermal expansion coefficient were optimized through the variation of NiO/CGO particle size ration and their composition. The electrical conductivity of the cermet was increased abruptly at a certain Ni content and the percolation concentration was decreased with the decreasing particle size ratio. Anodic overpotential was also decreased with the decreasing particle size ratio. For a fixed ratio it showed a minimum value at 50 wt.%. Thermal expansion coefficient was increased monotonically with increasing Ni contents, however it did not depend on the size ratio. With three properties taken into account, the cermet of particle size ration of 0.03 and composition of 50 wt.% was judged to be optimal as the anode.

• 한국기계가공학회지
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• 제21권2호
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• pp.23-30
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• 2022

After drilling, reaming is required to process a workpiece for obtaining an excellent surface quality. In general, a cermet is defined as a "composite of a ceramic hard phase and metal-bonded phase." Cermets have excellent abrasion resistance, thermal resistance, and performance in finishing operations that require surface roughness and processing precision. However, although cermets have significant advantages, research on them is insufficient. In this study, workpiece SM45C was machined using drills and cermet reamers. The cermet reamer was processed for drag finishing for 0, 4, and 6 min. The experimental results showed the effects of drag finishing on surface roughness and dimensional accuracy.

• 한국태양에너지학회 논문집
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• 제32권4호
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• pp.43-50
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• 2012

Metal-metal oxide (M-M oxide) cermet solar selective coatings with a double cermet layer film structure were deposited on the Al-deposited glass substrate by using a directed current (DC) magnetron sputtering technology. M oxide (CrO and ZrO) was used as the ceramic component in the cermets, and Cr and Zr used as the metallic components. In addition, black Cr (Cr-$Cr_2O_3$ cermet) solar selective coatings were deposited on the Ni-plated Cu substrate by using a electroplating method for comparison. The thermal stability tests were carried out for performance evaluation of solar coatings. Reflectance measurements were used to evaluate both solar absorptance(${\alpha}$) and thermal emittance (${\epsilon}$) of the solar coatings before and after thermal testing by using a spectrometer. Optical properties of optimized cermet solar coatings were ${\alpha}{\simeq}0.94-0.96$ and ${\epsilon}{\simeq}0.1$ ($100^{\circ}C$). The results of thermal stability test of M-M oxide solar coatings showed that the Cr-CrO cermet solar selective coatings were more stable than the Zr-ZrO cermet selective coatings at temperature of both $400^{\circ}C$ in air and $450^{\circ}C$ in vacuum. The black Cr solar selective coatings were degraded in air at temperature of $400^{\circ}C$. The main optical degradation modes of these coatings were diffusion of metal atoms, and oxidation.

• 한국분말재료학회지
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• 제25권5호
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• pp.408-414
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• 2018

This study investigates the microstructure and wear properties of cermet (ceramic + metal) coating materials manufactured using high velocity oxygen fuel (HVOF) process. Three types of HVOF coating layers are formed by depositing WC-12Co, WC-20Cr-7Ni, and Cr3C2-20NiCr (wt.%) powders on S45C steel substrate. The porosities of the coating layers are $1{\pm}0.5%$ for all three specimens. Microstructural analysis confirms the formation of second carbide phases of $W_2C$, $Co_6W_6C$, and $Cr_7C_3$ owing to decarburizing of WC phases on WC-based coating layers. In the case of WC-12Co coating, which has a high ratio of $W_2C$ phase with high brittleness, the interface property between the carbide and the metal binder slightly decreases. In the $Cr_3C_2-20CrNi$ coating layer, decarburizing almost does not occur, but fine cavities exist between the splats. The wear loss occurs in the descending order of $Cr_3C_2-20NiCr$, WC-12Co, and WC-20Cr-7Ni, where WC-20Cr-7Ni achieves the highest wear resistance property. It can be inferred that the ratio of the carbide and the binding properties between carbide-binder and binder-binder in a cermet coating material manufactured with HVOF as the primary factors determine the wear properties of the cermet coating material.

• 한국자원식물학회지
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• 제15권2호
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• pp.172-176
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• 2002

토란 재배시 종우가 부족할 경우 절편자우를 종우로 활용하는 방법을 연구하고자 본 시험을 실시한 결과는 다음과 같다. 1. 토란의 출현은 절편자우의 크기 별로 차이가 인정되지 않았고, 출현율은 90% 이상 출현되었다. 2. 생육은 절편자우가 클수록 엽병장이 크고 엽병속수가 많아 양호하였다. 3. 토란 절편자우의 크기에 따른 괴경과 부산물인 엽병의 수량은 크기간에 유의성이 인정되어 절편자우가 클수록 수량이 증수되는 경향으로 절편자우 20g을 종우로 사용할 경우 10g당 1,981kg을 생산할 수가 있었다. 이와 같은 결과로 보아 절편자우가 20g 이상인 것을 종우로 사용할 경우 토란의 재배가 가능할 것으로 본다.

• 한국기계가공학회지
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• 제18권5호
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• pp.17-22
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• 2019

In this study, Cermet Reamers for planet carrier was manufactured and the machining characteristics were analyzed through processing experiment. Cermet reamer with ∅14, ∅15, ∅18, and ∅21mm was used and machining characteristics were compared and analyzed by observing tool wear, machining hole dimensions and surface roughness. In the flank wear of the tool, the result is less than 0.2mm, which is the target value for each tool size. The experimental results of the machining hole dimensions show the results of the process control range of 3/100 or less according to the size of the tool. Also, the surface roughness measurement result showed a value of less than $0.5{\mu}m$ in the process control range for each tool size. As a result of observing the experimental results of each ∅, the results satisfied the process standard in both the tool wear, the machining hole dimension and the surface roughness.

• 한국세라믹학회지
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• 제35권7호
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• pp.749-756
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• 1998

TiC-Ni and TiC-Ni-Mo cermet powders were produced by Self-propagating High temperature Synthesis (SHS) process. The cooling rate of synthesized powders were controlled by using the V-shaped copper jig and the carbide size decreased with increasing the cooling rate I. e decreasing the width of copper jig Round shape carbide particles were produced after SHS reaction in TiC-Ni as well as TiC-Ni-Mo powders. Local segregation of Mo rich phases was observed in SHS powder of TiC-Ni-Mo and the uneven dis-triobution of Mo promoted the faster growth rate of carbide particles during sintering compared to the same composition specimen with commercial TiC powder. Howogeneous microstructure of TiC-Ni-Mo cermet was obtained when the elemental Mo powder was mixed with the SHS powder of TiC-Ni.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 춘계총회 및 연구발표회 초록집
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• pp.150.2-150
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• 2003