통합 검색 | Korea Science

김형준;황순영;권영각
- 대한용접접합학회:학술대회논문집
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- 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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- pp.311-313
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- 2004
WC-12-17%Co powders with nano- and micro-structures were deposited by cold spray process using nitrogen and helium gases. The results show that there is no detrimental phase transformation and/or decarburization of WC by cold spray deposition as expected. It is also observed that nano-sized WC in the feedstock powder is maintained in the cold spray deposition. It is demonstrated that it is possible to fabricate the nano-structured WC-Co coating with low porosity and very high hardness (-2050 HV) by cold spray deposition with reasonable powder preheating.
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Kim, Hwan-Tae;Park, Dong-Wook;Kim, Ji-Soon;Kwon, Young-Soon;Kwon, Hye-Suk;Baek, Eung-Ryul
- 한국분말재료학회지
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- 제10권3호
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- pp.176-180
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- 2003
Pure WC powders which does not include a binder phase were consolidated by spark plasma sintering (SPS) process at 1600~185$0^{\circ}C$ for 0~30 min under 50 MPa. Microstructure alid mechanical properties of binderless WC prepared by SPS were investigated. With increasing sintering temperature, sintered density and Vickers hardness of binderless WC increased. The fracture toughness of binderless WC was 7~15 MPa $m^{1/2}$ depending on the sintered density and decreased with increasing the Vickers hardness. It is found that the binderless WC prepared by SPS at 175$0^{\circ}C$ for 10 min under 50 MPa showed nearly full densification with fine-grained structure and revealed excellent mechanical properties of high hardness (~HV 2400) and considerably high fracture toughness (~7 MPa $m^{1/2}$).
https://doi.org/10.4150/KPMI.2003.10.3.176 인용 PDF KSCI

양희승;피재환;김유진
- 한국분말재료학회지
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- 제18권3호
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- pp.277-282
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- 2011
[ $LiCoO_2$ ] a cathode material for lithium rechargeable batteries, was prepared using recycled $Co_3O_4$. First, the cobalt hydroxide powders were separated from waste WC-Co hard metal with acid-base chemical treatment, and then the impurities were eliminated by centrifuge method. Subsequently, $Co_3O_4$ powders were prepared by thermal treatment of resulting $Co(OH)_2$. By adding a certain amount of $Li_2CO_3$ and $LiOH{\cdot}H_2O$, the $LiCoO_2$ was obtained by sintering for 10 h in air at $800^{\circ}C$. The synthesized $LiCoO_2$ particles were characterized by X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) analysis.
https://doi.org/10.4150/KPMI.2011.18.3.277 인용 PDF KSCI

Cho, T.Y.;Yoon, J.H.;Kim, K.S.;Baek, N.K.;Song, K.O.;Youn, S.J.;Hwang, S.Y.;Chun, H.G.
- 한국표면공학회지
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- 제39권6호
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- pp.295-301
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- 2006
Hard chrome plating has been used in surface hard coating over 50 years both for applying hard coating and re-building of worn components. Hard chrome plating solution and mist pollute environment with very toxic $Cr^{6+}$(hex-Cr) known as carcinogen which causes lung cancer, High velocity oxy-fuel (HVOF) thermal spray coatings of WC base cermet and Co-alloy powders are the most promising candidates for the replacement of the traditional hard chrome plating. Surface properties, wear, and friction behaviors of micron size Co-alloy (T800) and micron size WC-l2Co (WC-Co) have been studied for the application as hard coatings. The temperature dependence of wear and friction behaviors of T800 and WC-Co have been investigated at the temperature of $25^{\circ}C$ and $538^{\circ}C$ for the application to high speed spindle.
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