• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.826-827
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• 2006

Copper infiltration is demonstrated as a viable solution to achieve higher mechanical properties by filling the interconnected porosities of a ferrous structure with copper infiltrant. This paper will present the results of a design of experiments study based on the selected processing variables in the copper infiltration process. The variables are the following: Infiltrating temperatures, infiltrating time at pre-heat zone and hot zone, the green density of iron part, the migration of copper into the iron part at different processing conditions. The results show the flexibility of the infiltration process to attain certain mechanical properties by changing the processing conditions.

• 한국분말재료학회지
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• 제17권4호
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• pp.276-280
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• 2010

In the present work, ethylene glycol-based (EG) copper oxide nanofluids were synthesized by pulsed wire evaporation method. In order to explode the pure copper wire, high voltage of 23 kV was applied to the both ends of wire and argon/oxygen gas mixture was used as reactant gas. EG-based copper oxide nanofluids with different volume fraction were prepared by controlling explosion number of copper wire. From the transmission electron microscope (TEM) image, it was found that the copper oxide nanoparticles exhibited an average diameter about 100 nm with the oxide layer of 2~3 nm. The synthesized copper oxide consists of CuO/$Cu_2O$ phases and the Brunauer Emmett Teller (BET) surface area was estimated to be $6.86\;m^2\;g^{-1}$. From the analyses of thermal properties, it is suggested that viscosity and thermal conductivity of EG-based copper oxide nanofluids do not show temperature-dependent behavior over the range of 20 to $90^{\circ}C$. On the other hand, the viscosity and thermal conductivity of EG-based copper oxide nanofluids increase with volume fraction due to the active Brownian motion of the nanoparticles, i.e., nanoconvection.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2003년도 춘계학술강연 및 발표대회
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• pp.26-26
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• 2003

• 대한기계학회논문집A
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• 제32권5호
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• pp.379-386
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• 2008

Densification behavior of dissimilar material powder (copper and pure iron powder) under die compaction was investigated. Experimental data were obtained for copper and pure iron powder compacts with various volume ratios under die compaction. Dissimilar material powder was simultaneously compacted into a jointed cylindrical compact with different powder materials in inner and outer part, respectively. To simulate densification behavior of dissimilar material powder, elastoplastic constitutive equation proposed by Shima and Oyane was implemented into a finite element program (ABAQUS) under die compaction. Finite element results were compared with experimental data for densification, deformed geometry and density distribution of powder compacts under die compaction.

• 청정기술
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• 제27권3호
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• pp.240-246
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• 2021

COF (Chip on film)용 폐에칭용액 내 구리가 약 3.5% 함유되어 있으며, 철 시편을 사용한 시멘테이션을 통해 구리를 회수하고자 하였다. 철 시편 3종류(플레이트, 칩, 분말)에 따른 시멘테이션 반응에 미치는 영향을 조사하였으며, 구리의 회수율을 높이고자 구리에 대한 철의 몰 비를 변수로 하였다. 반응 전·후 용액 내 시간에 따른 구리 농도의 변화를 확인하였으며, 몰 비를 증가시킬수록 초기 용액 내 구리 함량이 급격히 줄어드는 경향이 나타났다. 상온에서 1시간의 시멘테이션 반응 후 철 시편의 비표면적 값이 큰 플레이트, 칩, 분말 순으로 구리의 회수율이 증가하였다. 회수된 분말은 X선 회절 분석기(X-ray diffraction, XRD), 주사전자현미경(scanning electron microscopy, SEM) 및 에너지 분산형 분광분석법(Energy-dispersive X-ray spectroscopy, EDM) 분석을 통해 결정상과 결정 형태를 확인하였으며, 철 분말의 경우에는 회수된 구리 분말에 미반응된 철 성분이 혼재하였다. 구리에 대한 철의 몰 비 4의 조건으로 철 칩을 사용하였을 때, 구리 회수율 약 98.4%로 최적 조건으로 달성하였다.

• 한국분말재료학회지
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• 제9권4호
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• pp.227-234
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• 2002

For the austenitic stainless steel (304L) manufactured by metal injection molding(MIM), the effects of copper content and sintering temperature on the mechanical properties, antibacterial activities, corrosion resistance, and electric resistances were investigated. The specimens were prepared by injection molding of the premixed powders of water-atomized 304 L and Cu with poly-acetyl binders. The green compacts were prepared with various copper contents from 0 to 10 wt.% Cu, which were debound thermally at 873 K for 7.2 ks in $N_2$gas atmosphere and subsequently sintered at various temperatures from 1323 K to 1623 K for 7.2 ks in Ar gas atmosphere. The relative density and tensile strength of the sintered compacts showed the minimum values at 5 and 8 wt.% Cu, respectively. Both the relative density and the tensile strength of the specimen with 10 wt.% Cu sintered at 1373 K showed the highest values, higher than those of copper-free specimen. Antibacterial activities investigated by the plastic film contact printing method for bacilli and the quantitative analysis of copper ion dissolved in water increased as the increase of the copper content to stainless steels. It was also verified by the measurement of pitting potential that the copper addition in 304 L could improve the corrosion resistance. Furthermore the electric conductivity increased with the increase of copper content.

• Advances in materials Research
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• 제5권3호
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• pp.131-140
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• 2016

Copper/silicon nitride ($Cu/Si_3N_4$) composites are fabricated by powder technology process. Copper is used as metal matrix and very fine $Si_3N_4$ particles (less than 1 micron) as reinforcement material. The investigated powder were used to prepare homogenous ($Cu/Si_3N_4$) composite mixtures with different $Si_3N_4$ weight percentage (2, 4, 6, 8 and10). The produced mixtures were cold pressed and sintered at different temperatures (850, 950, 1000, $1050^{\circ}C$). The microstructure and the chemical composition of the produced $Cu/Si_3N_4$ composites were investigated by (SEM) and XRD. It was observed that the $Si_3N_4$ particles were homogeneously distributed in the Cu matrix. The density, electrical conductivity and coefficient of thermal expansion of the produced $Cu/Si_3N_4$ composites were measured. The relative green density, sintered density, electrical conductivity as well as coefficient of thermal expansion were decreased by increasing the reinforcement phase ($Si_3N_4$) content in the copper matrix. It is also founded that the sintered density and electrical conductivity of the $Cu/Si_3N_4$ composites were increased by increase the sintering temperature.

• 한국분말재료학회지
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• 제19권5호
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• pp.343-347
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• 2012

In this study, an oxygen plasma treatment was used as a low temperature debinding method to form a conductive copper feature on a flexible substrate using a direct printing process. To demonstrate this concept, conductive copper patterns were formed on polyimide films using a copper nanoparticle-based paste with polymeric binders and dispersing agents and a screen printing method. Thermal and oxygen plasma treatments were utilized to remove the polymeric vehicle before a sintering of copper nanoparticles. The effect of the debinding methods on the phase, microstructure and electrical conductivity of the screen-printed patterns was systematically investigated by FE-SEM, TGA, XRD and four-point probe analysis. The patterns formed using oxygen plasma debinding showed the well-developed microstructure and the superior electrical conductivity compared with those of using thermal debinding.

• 한국분말재료학회지
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• 제16권2호
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• pp.131-137
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• 2009

This paper deals with the effects of the surfactant and preplate process (sensitization and activation) on electroless copper plating on carbon nano-fiber (CNF). Ultrasonic irradiation was applied both during dispersion of CNF and during electroless plating containing preplate process. The dispersion of CNF and flatness of the plated copper film were discussed based on the changes in surfactant concentration and preplate process time. It was clearly shown that high concentration of surfactant and long time of preplate process could promote the agglomeration of CNF and uneven copper plating on CNF.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.203-206
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• 2004

Copper-based bulk amorphous alloy composite was synthesized by using the copper-coated $Cu_{54}Ni_{6}Zr_{22}Ti_{18}$ amorphous powder which was obtained by argon gas atomization. The amorphous powder having a super-cooled liquid region of 53 K was coated by crystalline copper by electroless coating. The consolidation was carried out by manufacturing performs and by the subsequent warm extrusion at 743 K. During the compression test at the room temperature, the composite containing a large fraction of crystalline copper displayed a larger plastic strain after yielding. FEM simulation revealed change in fracture modes in the composites depending on the amount of crystalline copper in the composites.