• 대한금속재료학회지
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• 제50권6호
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• pp.419-425
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• 2012

The purpose of this research was to develop a low Ni austenitic cast iron through replacing Ni by Cu and Mn because they are cheaper than Ni. The effect of the Cu content (6-12 wt%) on the microstructure characteristics was investigated in Fe-3%C-16%(Ni+Cu+Mn) cast iron. Contrary to general effect of the Cu on cast iron, the result of the microstructure analysis indicated that bainite and cementite were formed in high Cu content (>8 wt%Cu). A crystallized Cu-solution (Cu-Mn) phase and MnS in the Cu-solution were formed. The quantity of those phases increased as the Cu content increased. Consequently, the high Cu content in the composition ratio (Ni+Cu+Mn=16%) caused the formation of Cu-Mn/MnS and those phases decreased the effect of Cu and Mn on austenite formation. For this reason, bainite and cementite were formed in high Cu content.

• 한국분말재료학회지
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• 제4권4호
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• pp.283-290
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• 1997

$Ti_5Si_3$ intermetallics containing 0-6 wt% of Cu were made by reactive sintering (RS) under vacuum using elemental powder mixtures (Process 1), electro-pressure sintering (EPS) using RS'ed materials (Process2), and EPS using elemental powder mixtures (Process 3). Relatively low dense titanium silicides were gained by process 1, in which porosity decreased with increasing Cu content. For example, porosity changed from 42 to 19.4% with the increase in Cu content from 0 to 6 wt%, indicating that Cu is a useful sintering aid. The titanium silicides fabricated by Process 2 had a higher density than those by Process 1 at given composition, and porosity decreased with increasing Cu content. For example, porosity decreased from 38 to 6.8% with the change in Cu content from 0 to 6 wt%. A high dense titanium silicides were obtained by Process 3. In this Process, porosity decreased a little by Cu addition, and was almost insensitive to Cu content. Namely, about 9 or 7% of porosity was shown in 0 or 1-6 wt% Cu containing silicides, respectively. The hardeness increased by Cu addition, and was not changed markedly with Cu content for the silicides fabricated by Process 3. This tendency was considered to be resulted from porosity, hardening of grain interior by Cu addition, and softening of grain boundary by Cu-base segregates. All these results suggested that EPS using elemental powder mixtures (Process 3) is an effective processing method to achieve satisfactorily dense titanium silicides.

• 한국자기학회지
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• 제3권4호
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• pp.310-313
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• 1993

Cu-Ni를 기저층으로 한 (100) Cu/Co 인공초격자에서 기저층에 첨가된 니켈의 함량이 자기저항에 미치는 영향을 조사하였다. 니켈의 함량이 증가하면서 인공초격자의 우선 방위가 fcc(100)에서 fcc(111)으로 변화하였는데 이는 기저층의 우선 방위가 바뀌었기 때문인 것으로 밝혀졌다. 니켈의 함량이 6%일때 [Cu(19 .angs. )/Co(30 .angs. )]/sub 20/ | Cu-6%Ni(200 .angs. )/Si 시편의 경우에 177 Oe에서 26.7%의 큰 자기저 항을 얻을 수 있었다.

• 한국분말재료학회지
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• 제13권1호
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• pp.33-38
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• 2006

The effect of Cu content on microstructure and mechanical properties of nano-sized Cu dispersed $Al_2O_3(Al_2O_3/Cu)$ nanocomposites was investigated. The nanocomposites with Cu content of 2.5 to 10 vol% were prepared by reduction and hot-pressing of $Al_2O_3/CuO$ powder mixtures. The nanocomposites with Cu content of 2.5 and 5vol% exhibited the maximum fracture strength of 820MPa and enhanced toughness compared with monolithic $Al_2O_3$. The strengthening was mainly attributed to the refinement of $Al_2O_3$ matrix grains. The toughening mechanism was discussed by the observed microstructural feature based on crack bridging.

• 한국결정성장학회지
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• 제18권1호
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• pp.33-37
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• 2008

Sn-Sb-Cu-Ni-Cd whitemetal에서 Cu와 Sb가 미세조직과 기계적 특성에 미치는 영향을 조사하였다. Cu 함량이 0.05 wt%인 whitemetal에서는 화합물 상이 관찰되지 않았지만 Cu 함량이 증가함에 따라 별 모양 또는 침상 $Cu_6Sn_5$ 상이 관찰되었다. 인장강도는 Cu 함량이 5% 까지는 증가하다가 그 이상에서는 거의 일정하게 유지되었다. 반면에 경도는 경질상이 증가하기 때문에 계속 증가하였다. 또한 Sb 함량이 증가함에 따라 입방형 SbSn 상이 $Cu_6Sn_5$ 상과 함께 관찰되었다. 인장강도와 경도는 Sb 함량이 많아질수록 증가하였고 연선율은 감소하였다.

• 한국표면공학회지
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• 제52권4호
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• pp.227-232
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• 2019

Mo-N based coatings have been studied for enhancing mechanical characteristics of thin films. In the case of Mo-X-N coatings, the microstructure and mechanical properties can be affected by the addition of the third element. In this work, Mo-Cu-N coatings were successfully fabricated with varying the Cu content from 4.5 at% to 31 at% by the co-sputtering method. Thus, properties of the coatings were analyzed by EDS, SEM, XRD, AFM, nano indentation and scratch test techniques. From observed results, MoxN bonds were made in a nitrogen atmosphere and Cu elements were present at grain boundaries. In addition, coatings with the Cu content above 14 at% had a Cu3N peak in the XRD results. Thus, it is suggested that the formation of Cu3N phase affected the microstructure and mechanical properties of Mo-Cu-N coatings. Mechanical properties of Mo-Cu-N coatings were found to be relatively better at Cu content of about 12 at%.

• Journal of Welding and Joining
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• 제23권6호
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• pp.93-98
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• 2005

The purpose of this study is to investigate the characteristics of pb-free $Zn-(3\~6)\%Al-(1\~6)\%Cu$ solder alloys for ultra high temperature(>573K) which applied to air craft, space satellite, automotive, oil, gas well exploration and data logging of geo-thermal wells. Melting range, solderability, electric resistivity, microstructure and mechanical properties were examined with solder alloys casted in Ar gas atmosphere. $Zn-4\%Al-(1\~3)\%Cu,\;Zn-5\%Al-(2\~4)\%Cu\;and\;Zn-6\%Al-(3\~5)\%Cu$ alloys satisfied the optimum melting range of 643 to 673k for ultra high temperature solder. A melting temperature increased with increasing Cu content, but decreased with increasing Al content. The spreadability was improved with increasing hi content. But the content of Cu had no effect on the spreadability. The electric resistivity was lowered with increasing Al and decreasing Cu content. In all Zn-Al-Cu solder alloys, primary dendritic $\varepsilon$ phase(Zn-Cu), dendritic $\eta$ phase(Zn-Cu-Al), $\alpha(Al-Zn)-\eta$ eutectic and eutectoid phase were observed. The addition of Al increased the volume fraction of eutectic and eutectoid phase and it decreased f phases. Also, the addition of Cu increased slightly the volume fraction of e, the eutectic and eutectoid phases. With increasing total content of Al and Cu, a hardness and a tensile strength were linearly increased, but anelongation was linearly decreased.

• Transactions on Electrical and Electronic Materials
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• 제12권1호
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• pp.20-23
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• 2011

Amorphous Ti-(50-x)Ni-xCu (at%) (x = 20, 25, 27, 30) alloy ribbons were prepared by melt spinning. Subsequently, the crystallization behavior of the alloy ribbons was investigated by X-ray diffraction and differential scanning calorimetry. ${\Delta}T$ (the temperature gap between $T_g$ and $T_x$) increased from 33 K to 47 K and the wavenumber ($Q_p$) decreased from 29.44 $nm^{-1}$ to 29.29 $nm^{-1}$ with increasing Cu content from 20 at% to 30 at%. The activation energy for crystallization decreased from 188.5 kJ/mol to 170.6 kJ/mol with increasing Cu content from 20 at% to 25 at%; afterwards, the activation energy remained near constant. Crystallization occurred in two-stage: amorphous-B2-$TiCu_2$ in Ti-Ni-Cu alloys with Cu content less than 25 at%, while it occurred in three-stage; amorphous-B2-TiCu-$TiCu_2$ in Ti-Ni-Cu alloys with Cu content more than 27 at%.

• 한국환경농학회지
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• 제13권1호
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• pp.1-9
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• 1994

대기오염에 따른 Cu의 함량변화 차이를 구명하기 위하여 대기형 오염물질 방출지역으로 장항제련소 인근지역의 논 토양을 중심으로 1982년도에 표${\cdot}$심토로 구분 채취한 것과 1990년도에 채취한 토양시료, 그리고 1990년에 토양시료 채취지역에서 재배된 수도체 중의 Cu 함량을 분석하여 그 변화 요인을 추적 분석하였다. 제련소 인근지역의 토양 중 Cu함량은 5.1-391.0 mg $kg^{-1}$였고, 평균함량이 1990년 토양이 1982년도 토양 보다 높았으며, 1982년도 표토 중 Cu함량은 1990년도 표${\cdot}$심토 간 Cu함량과 유의성 있는 상관을 나타냈다. 배연의 중심으로부터 동쪽방향에서 거리별 Cu함량변화가 뚜렷하였고, 그 정도는 동쪽>북북동=북동>북쪽 순으로 작아졌다. 배연에 의한 오염반경은 동쪽 5㎞, 북북동과 북동이 3㎞였으며, 1982년도 토양 중 Cu함량은 유효인산, 유효규산, 치환성 $Ca^{++}$과 $Na^+$ 양과 유의한 상관성을 나타내었다. 이 지역 수도체의 엽초, 줄기, 현미중 Cu함량은 토양 중 Cd, Zn, Cu 및 Pb함량과 유의성 있는 상관관계를 나타내었고, 현미 중의 Cu 함량은 0.4-3.6 mg $kg^{-1}$ 이었으며 수도체의 부위에 따라서는 현미 중 Cu 함량의 13.75배까지 축적되는 경우도 있었다. 대기오염에 의한 토양 중 Cu 함량은 토양 중 Zn 및 Pb함량과도 유의한 상관관계를 나타내고 있어서 이들 금속들이 오염물질로서 함께 유입되고 있음을 나타냈다.

• Current Photovoltaic Research
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• 제3권1호
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• pp.27-31
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• 2015

It is known that sulfide at the $Cu(In,Ga)Se_2$ ($CIGSe_2$) surface plays a positive role in $CIGSe_2$ solar cells. We investigated the substitution of S with Se on the $CIGSe_2$ surface in S atmosphere. We observed that the sulfur content in the $CIGSe_2$ films changed according to sulfurization temperature and Cu/(In+Ga) ratio. The sulfur content in the $CIGSe_2$ films increased with increasing the annealing temperature and Cu/(In+Ga) ratio. Also Cu migration toward the surface increased at higher temperature. Since high Cu concentration at the $CIGSe_2$ surface is detrimental role, it is necessary to reduce the S annealing temperature as low as $200^{\circ}C$. The cell performance was improved at $200^{\circ}C$ sulfurization.