화학기상응축법에 의한 WC 나노분말의 합성연구

김진천,하국현,최철진,김병기 한국분말야금학회 2002 한국분말야금학회 학술대회논문집 Vol.2002 No.1

나노미터 크기의 결정립을 가지는 나노분말 및 나노복합분말의 제조와 특성에 관한 연구가 매우 활발하다. 나노복합분말의 제조방법에는 기상증발후 응축법, 화학응축법, 기계적합금법 등이 있으나, 고순도 및 균일한 크기분포의 분말과 응집되지 않은 분말의 제조 조건을 가장 잘 만족하는 방법은 화학기상응축법(Chemical Vapor Condensation; CVC)이다. 본 연구그룹 에서는 CVC밤법으로 이용하여 공구/금형재료에 가장 많이 사용되는 WC/Co 합금

Spray conversion 법으로 제조된 W/Cu 나노복합분말의 소결특성 및 단조특성 평가

김태형,노준웅,김은표 한국분말야금학회 2002 한국분말야금학회 학술대회논문집 Vol.2002 No.1

최근 한국기계연구원에서 개발된 Mechanochemical process (MCP)는 Spray conversion 법에 의하여 나노크기의 W/Cu 복합 분말을 제조하는 방법으로서, 현재 (주)나노테크에서 산업화를 위한 시험/개발이 진행 중이다. 이 방법에 의하여 W /1 0 ~ 40wt. %Cu 조성의 초미렵 W/Cu 복합 분말의 양산화가 가능하게 됨으로써, 나노복합분말을 사용한 초미립 W/Cu 합금의 소결 제조 연구 역시 나 노태크에서 분말사업화와

분말 반응법에 의한 YBa₂Cu₃O_7-y 합성과 벌크 초전도체의 제조

전영주,박승연,유병윤,박순동,김찬중,Jeon,,Young,Ju,Park,,Seung,Yeon,You,,Byung,Youn,Park,,Soon-Dong,Kim,,Chan-Joong 한국분말야금학회 2013 한국분말야금학회지 Vol.20 No.2

$YBa_2Cu_3O_{7-y}$ (Y123) powders for the fabrication of bulk superconductors were synthesized by the powder reaction method using $Y_2O_3$ (99.9% purity), $BaCO_3$ (99.75%) and CuO (99.9%) powders. The raw powders were weighed to the cation ratio of Y:Ba:Cu=1:2:3, mixed and calcined at $880^{\circ}C-930^{\circ}C$ in air with intermediate repeated crushing steps. It was found that the formation of Y123 powder was more sensitive to reaction temperature than reaction time. The calcined Y123 powder and a mixture of (Y123 + 0.25 mole $Y_2O_3$ + 1 wt.% $CeO_2$, $Y_{1.5}Ba_2Cu_3O_x$ (Y1.5)) were used as raw powders for the fabrication of poly-grain or single grain superconductors. The superconducting transition temperature ($T_{c,onset}$) of the sintered Y123 sample was 91 K and the transition width was as large as 11 K, whereas the $T_{c,onset}$ of the melt-grown Y1.5 sample was 90.5 K and the transition width was 3.5 K. The critical current density ($J_c$) at 77 K and 0 T of the sintered Y123 was 700 $A/cm^2$, whereas the $J_c$ of the top-seeded melt growth (TSMG) processed Y1.5 sample was $3.2{\times}10^4\;A/cm^2$. The magnetic flux density (H) at 77 K of the TSMG-processed Y123 and Y1.5 sample showed the 0.53 kG and 2.45 kG, respectively, which are 15% and 71% of the applied magnetic field of 3.5 kG. The high H value of the TSMG-processed Y1.5 sample is attributed to the formation of the larger superconducting grain with fine Y211 dispersion.

산화텅스텐 분말을 이용하여 금속 기판 위에 텅스텐 박막을 코팅하는 방법에 관한 연구

박윤식,김성수,이성,홍문희,노준웅 한국분말야금학회 2001 한국분말야금학회 학술대회논문집 Vol.2001 No.1

가스분무 Fe계 비정질 분말과 유체 내 전기선 폭발에 의한 나노 Cu 분말의 복합화와 방전플라즈마 소결

김진천,구왕회,유주식,Kim,,Jin-Chun,Goo,,Wang-Heo,Yoo,,Joo-Sik 한국분말야금학회 2008 한국분말야금학회지 Vol.15 No.4

Fe based ($Fe_{68.2}C_{5.9}Si_{3.5}B_{6.7}P_{9.6}Cr_{2.1}Mo_{2.0}Al_{2.0}$) amorphous powder were produced by a gas atomization process, and then ductile Cu powder fabricated by the electric explosion of wire(EEW) were mixed in the liquid (methanol) consecutively. The Fe-based amorphous - nanometallic Cu composite powders were compacted by a spark plasma sintering (SPS) processes. The nano-sized Cu powders of ${\sim}\;nm$200 produced by EEW in the methanol were mixed and well coated with the atomized Fe amorphous powders through the simple drying process on the hot plate. The relative density of the compacts obtained by the SPS showed over 98% and its hardness was also found to reach over 1100 Hv.

스퍼터링 타겟용 Cu-50In-13Ga 3원계 합금 분말의 소결 및 압연 거동

김대원,김용호,김정한,김대근,이종현,최광보,손현택,Kim,,Dae-Won,Kim,,Yong-Ho,Kim,,Jung-Han,Kim,,Dae-Guen,Lee,,Jong-Hyeon,Choi,,Kwang-Bo,Son,,Hyeon-Taek 한국분말야금학회 2012 한국분말야금학회지 Vol.19 No.4

In this study, we mainly focus on the study of densification of gas-atomized Cu-50 wt.%In-13 wt.%Ga alloy powder without occurrence of crack during the forming process. Cu-50 wt.%In-13 wt.%Ga alloy powder was consolidated by sintering and rolling processes in order to obtain high density. The phase and microstructure of formed materials were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical microscopy (OM), respectively. Warm rolling using copper can result in the improvement of density. The specimen obtained with 80% of rolling reduction ratio at $140^{\circ}C$ using cooper can have the highest density of $8.039g/cm^3$.

금속 Powder Bed Fusion(PBF) 공정용 분말의 특성평가 방법 및 관련 연구 동향

이빈,김대겸,김영일,김도훈,손용,박경태,김택수 한국분말야금학회 2020 한국분말야금학회지 Vol.27 No.6

A well-established characterization method is required in powder bed fusion (PBF) metal additive manufacturing, where metal powder is used. The characterization methods from the traditional powder metallurgy process are still being used. However, it is necessary to develop advanced methods of property evaluation with the advances in additive manufacturing technology. In this article, the characterization methods of powders for metal PBF are reviewed, and the recent research trends are introduced. Standardization status and specifications for metal powder for the PBF process which published by the ISO, ASTM, and MPIF are also covered. The establishment of powder characterization methods are expected to contribute to the metal powder industry and the advancement of additive manufacturing technology through the creation of related databases.

원심에멀션법에서의 금속 분말의 형성 기구

장성준,윤우영 한국분말야금학회 1993 한국분말야금학회 학술대회논문집 Vol.1993 No.1

분말의 제조에 미치는 기계적 합금화 공정변수의 영향

양회운,이광민 한국분말야금학회 1998 한국분말야금학회 학술대회논문집 Vol.1998 No.1

등통로각압축이 결합된 압출 공정에 의한 알루미늄 분말의 치밀화 거동

윤승채,김형섭 한국분말야금학회 2008 한국분말야금학회지 Vol.15 No.3

Aluminum alloys are not only lightweight materials, but also have excellent thermal conductivity, electrical conductivity and workability, hence, they are widely used in industry. It is important to control and enhance the densification behavior of metal powders of aluminum. Investigation on the extrusion processing combined with equal channel angular pressing for densification of aluminum powders was performed in order to develop a continuous production process. The continuous processing achieved high effective strain and full relative density at . Optimum processing conditions were suggested for good mechanical properties. The results of this simulation helped to understand the distribution of relative density and effective strain.