• Tribology and Lubricants
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• 제26권2호
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• pp.122-128
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• 2010

Focused Ion Beam (FIB) has been used for site-specific TEM sample preparation and small scale fabrication. Moreover, analysis on the surface microstructure and phase distribution is possible by ion channeling contrast of FIB with high resolution. This paper describes FIB applications and deformed surface structure induced by sliding. The effect of FIB process on the surface damage was explored as well. The sliding experiments were conducted using high purity aluminum and OFHC(Oxygen-Free High Conductivity) copper. The counterpart material was steel. Pin-on-disk, Rotational Barrel Gas Gun and Explosively Driven Friction Tester were used for the sliding experiments in order to investigate the velocity effect on the microstructural change. From the FIB analysis, it is revealed that ion channeling contrast of FIB has better resolution than SEM and the tribolayer is composed of nanocrystalline structures. And the thickness of tribolayer was constant regardless of sliding velocities.

• 자원리싸이클링
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• 제17권5호
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• pp.60-65
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• 2008

고순도 동 제조를 위해 황산동 전해액중에 존재하는 은(Ag)을 제거하기 위한 기초연구를 실시하였다. 이온교환수지법, 활성탄 흡착법, 구리분말 및 세선을 이용한 치환법, CuS침전법 등을 이용하여 Ag제거에 대한 실험을 실시하였으며, 은(Ag)제거 반응에 영향을 미칠 수 있는 반응온도, 반응시간, 첨가량 등에 대해 고찰하였다. 이들 방법중 CuS 침전법과 Lewatit TP214를 이용한 이온교환수지 방법이 효과적이었는데 특히 Lewatit TP214를 사용한 경우 초기 동전해액중, Ag 농도가 10ppm서 0.1ppm 이하 수준까지 제거가 가능하였다.

• 한국주조공학회지
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• 제29권5호
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• pp.198-203
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• 2009

In order to manufacture copper ultra fine wire used for bonding wire in integrated circuit package, continuous casting process, which can produce high purity copper rod with small cross section, and wiredrawing process have to be optimized to prevent wire brakeage during entire manufacturing process of fine wire. The optimum condition for producing copper rod with mirror surface has to established by investigation of the effects of several parameters such as withdrawal speed, superheat and rod diameter on grain morphology of the cast rod and on its drawing characteristics to fine wire. The purpose of this study is to propose the optimized process parameters in continuous casting process in order to produce cast rod without internal defects, and to predict microstructure orientation suitable for wire drawing process.

• Nuclear Engineering and Technology
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• 제24권2호
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• pp.163-167
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• 1992

고순도알루미늄중 불순물의 Parameter로 이용될수 있는 구리의 비파괴 방사화분석법의 고찰 및 23종의 극미량불순성분원소의 함량을 분석하였다. 즉 구리의 분석은 원자로의 속중성자에 의한 27Al(n,$\alpha$)24Na반응으로 생성되는 24Na의 방사능을 감소시키기 위하여 Thermal Column을 이용하였고 다른 조사공을 이용한 경우보다 약 100 배 정 도 방해 요인을 감소시킬 수 있었다. 24Na 에 의한 영향은 2-3 %범위 이하이었다. 이 방법에 의해 표준알루미늄(6 nine class)시료로부터 구리를 정량하였고 아울러 기타 불순원소들을 일상 방사화분석법에 의해 정량하였다. 구리의 함량은 0.54$\pm$0.08 ppm이었다. 이러한 결과는 문헌값과 비교할때 타당성이 있었고 일상분석에 이용할 수 있는 좋은 방법으로 여겨진다.

• 대한금속재료학회지
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• 제56권12호
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• pp.861-869
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• 2018

To determine the origin of the inhomogeneous microstructure and texture observed in drawn and annealed high purity copper wires, two kinds of drawing process conditions and their influence was investigated. The regular condition, based on a symmetric die, and a condition designed intentionally to produce an inhomogeneous shear deformation using an asymmetric die were employed. The difference in intensity of <111>-<100> distributed texture between the two wires confirmed that the wire drawn under the asymmetric die condition experienced a higher amount of shear deformation. The extensive shear strain in the wire drawn under the asymmetric die condition gave rise to inhomogeneous primary and secondary recrystallization behavior. After annealing at $200^{\circ}C$, grains with <100> texture, which were larger than the surrounding recrystallized grains, were extensively present on one half circle of the wire drawn under the asymmetric die condition, while larger grains with <100> were sparsely observed around the middle region of the wire drawn under the regular condition. Interestingly, the area where the larger grains with <100> texture existed was identical to the area where the high shear strain occurred during drawing in both wires. During annealing at $400^{\circ}C$, grains with <112> texture started to grow abnormally at the center of both wires as a result of secondary recrystallization. After annealing at $900^{\circ}C$ grains with <112> due to secondary recrystallization occupied the entire region of the wire drawn under the regular condition. On the other hand, in the wire drawn under the asymmetric die condition and then annealed at $900^{\circ}C$, the <100> oriented grains as a result of the normal grain growth of the larger <100> grains which were observed after annealing at $200^{\circ}C$, coexisted with the abnormally grown <112> grains. These results indicate that dynamic recrystallization induced by the shear strain during drawing plays an important role in the inhomogeneity of the microstructure and texture of wires after annealing.

• 한국재료학회지
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• 제16권5호
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• pp.285-291
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• 2006

Copper powders have been widely used in electrically conductive coatings, electrode materials et al. and are very prospective since they are cheaper than noble metal powders such as silver or palladium. In this study, copper powders for metal filler of EMI shielding have been prepared using a solvothermal process from $CuSO_4$, NaOH, Glucose, mixed solvent ($H_2O$: Ethanol) and hydrazine which was used as a reducing agent at various reaction conditions. The prepared copper powders showed finely dispersed spherical shape without agglomerate, uniform morphology, narrow size distribution, high purity and were about 400-700 nm in size. The prepared powders were characterized using XRD, SEM, TGA, XPS, particle size measurement and EMI shielding efficiency.

• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3151-3157
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• 2021

Copper is an important structural material in various nuclear energy applications, therefore the correct knowledge of copper cross sections is crucial. The presented paper deals with a validation of different copper transport libraries by means of activation of selected samples. An intense ²⁵²Cf(sf) source with a reference neutron spectrum was used as a neutron source. After irradiation, the samples were measured using a high purity germanium detector and the dosimeter reaction rates were inferred. These experimental data were compared with MCNP6 calculations using CENDL-3.1, JENDL-4.0, ENDF/B-VII.1, ENDF/B-VIII.0, JEFF-3.2 and JEFF-3.3 evaluated Cu transport libraries. The experiment specifically focuses on ⁵⁸Ni(n,p)⁵⁸Co, ⁹³Nb(n,2n)^92mNb, ¹⁹⁷Au(n,g)¹⁹⁸Au and ⁵⁵Mn(n,g)⁵⁶Mn dosimetry reactions. Evaluated activation cross sections of these dosimetric reactions were taken from the IRDFF-II library. The best library performance depends on the energy region of interest.

• 보존과학연구
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• 통권14호
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• pp.45-76
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• 1993

Au-Cu alloyed coating layer were found by Hg-amalgam process and it seemed to be used Cu-amalgam process similar to Au-amalgam. Coated layer is dense and unique, Thickness of layer was 1.5 to $18.0\mum$ which had 95.3 to 99.8% purity of gold Matrix metal mostly cosists of forged copper alloy which had high purity and ferrite ($\alpha$) strusture. It showed excellent refining technical level at that time. Aowever, the nail, ferrous matrix used for strength needed, composed of silver foil packed and gold layer for adherence between ferrous matrix and gold layer

• 공업화학
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• 제25권2호
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• pp.157-160
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• 2014

폐 젤리충진 통신케이블로부터 고순도 구리회수를 위하여 실리콘계 및 톨루엔계 합성 열매유와 폐식용유를 사용하여 적용성을 평가하였다. 실리콘계 오일의 경우 모든 조건에서 분리효율이 낮은 반면, 톨루엔계 오일 및 폐식용유의 경우 처리온도 및 시간을 조절함에 따라 높은 분리효율을 얻을 수 있었다. 폐식용유를 사용하는 50 kg급 밀폐형 대용량 설비를 이용하여 $300^{\circ}C$에서 60 min 이상 처리할 경우 99.2% 이상의 고순도 구리와이어를 100% 회수할 수 있었다.

• 소성∙가공
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• 제4권4호
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• pp.353-364
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• 1995

An inhomogeneous rolling texture of high purity aluminum has been observed by a multilayered rolling. The shear texture of (100)[110] component developed in the surface layer, and the copper type rolling texture developed in the middle and center layers. The through-thickness texture variation has been calculated by the full-constraint Taylor model combined with FEM. The calculated results are in good agreement with the measured data.