• 한국분말재료학회지
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• 제8권4호
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• pp.231-238
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• 2001

We combined Field-Activated Combustion Synthesis(FACS) with mechanical pressure to produce dense WC-20 vol.%Co composite in one step. The hardness, the fracture toughness and the relative density of the dense WC-20 vol.%Co were investigated. Under the application of 60 MPa pressure and 3000A current on the reactants, the relative density of WC-20 vol.%Co composite was 99.4%. The fracture toughness and hardness were $9.4 MPa.m^{1/2}$ and $1672kg\textrm{mm}^2$ respectively. The fracture toughness and hardness of WC-20 vol.%Co composite produced by FAPACS were lower than that of nanostructured composite, but similar to commercial ones. Therefore we concluded that the FAPACS method which can produce WC-20 vol.%Co within several minutes in one step is superior to conventional ones.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.346-347
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• 2006

New manufacturing processes, such as thermochemical, mechanochemical and chemical vapor condensation processes have been developed to obtain nanostructured WC/Co materials. Nanoscale size WC/Co composite powders of near 100-150nm can be synthesizes by thermochemical and mechanochemical processes using water soluble precursors. Non-agglomerated and nano sized WC powder can be synthesized by the chemical vapor condensation process using metallorganic precursors as starting materials. In this paper, the scientific and technical issues on synthesis and consolidation of nanostructured WC/Co alloys produced by new chemical processes are introduced.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2005년도 추계학술강연 및 발표대회강연 및 발표논문 초록집
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• pp.75-77
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• 2005

• 한국세라믹학회지
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• 제41권2호
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• pp.131-135
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• 2004

WC에 소량의 Co를 첨가하여 그에 따른 미세조직의 변화를 관찰하였다. 순수한 WC를 성형하여 그 윗부분에 Co를 올려놓고 195$0^{\circ}C$에서 소결을 행한 결과, WC시편에서는 Co상이 놓여 액상을 형성한 영역으로부터 거리에 따라 입자의 크기와 모양이 다른 활발한 비정상입성장이 관찰되었다. 그러나, Co상이 놓인 영역으로부터 떨어진 시편 아래 영역에서는 낮은 치밀화와 함께 비정상입성장은 일어나지 않았다. 즉, Co 액상량은 WC의 비정상입성장 현상에 지대한 영향을 주었으며, 이러한 비정장입정장 현상은 2차원 핵생성 기구와 그에 따른 입성장기구로 설명이 가능하였다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.332-333
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• 2006

The driving forces and the probable processes of WC-Co grain growth are reanalysed from recent data of interface energy and microstructure. Grain growth is driven by the disappearing of the high energy WC/WC and WC/Co interfaces with habit planes different from {0001}, ${10\bar{1}0}$ and ${11\bar{2}0}$ facets and by the area decrease of the WC/WC and WC/Co interfaces with {0001} and ${10\bar{1}0}$ habit planes. Grain growth mainly results of dissolution-precipitation. Abnormal grains are likely formed by defects assisted nucleation.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.350-351
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• 2006

A solid stage sinterizacion model of the WC-Co is applied on this work. These results are compaired with the experimental data obtained for nanometric and micrometric sinter powder in an electric furnace and micrometric in a plasma reactor (using Abnormal Glow Discharge AGD). The correlations obtained allow the prediction of the sintering behavior in AGD for nanometric powder. The activation of the solid state sintering is shown with the decraease of the WC size and the use of AGD

• 한국분말재료학회지
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• 제11권2호
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• pp.111-117
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• 2004

The oxidation behavior of 91 WC-9Co hardmetal in weight percentage has been studied in the present work as a part of the development of recycling process. The morphological and compositional changes of the WC-Co hardmetal with oxidation time at 90$0^{\circ}C$ were analyzed by using surface observation and X-ray diffraction. respective]y. As the oxidation time increased, the WC-Co hardmetal was continuously expanded to form porous oxide mixtures of $CoWO_4$ and $WO_3$. The morphology of porous oxide mixture was basically dependent on initial shape of the WC-Co hardmetal. From thermo-gravimetric (TG) analysis, it was found that the oxidation rate was increased with increasing oxidation temperature and oxygen content in the flowing atmospheric gas. The fraction of oxidation versus time curves showed S-curve relationship at a given of oxidation temperature. These oxidation behaviors of the WC-Co hardmetal were discussed in terms of previously proposed kinetic models.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 춘계학술강연 및 발표대회강연 및 발표논문 초록집
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• pp.38-38
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• 2006

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1998년도 춘계학술대회 및 발표대회 강연 및 발표논문 초록집
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• pp.20-21
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• 1998

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1999년도 춘계학술대회 및 발표대회 강연 및 발표논문 초록집
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• pp.18-18
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• 1999