• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1485-1487
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• 2000

A variety of target configurations in sputtering process have been proposed to deposit various structures of thin film alloys and compound films. In this study, we presented the comparative experimental results regarding to the characterization of properties of Cu-Ni thin films deposited by using a magnetron co-sputtering method, as a function of target configurations; one is using a single target with varying the area of Ni chips attached on the Cu target and another is using a dual-type target with two targets of Ni and Cu separated each other. Structural(d-spacing, crystal orientation, crystallite size, cross-sectional morphology) and electrical(resistivity) properties of deposited films are characterized and compared as a function of target configurations as well as deposition conditions.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.137-138
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• 2011

구리 이온은 -0.40V (vs. SCE)에서 전기화학적 환원이 일어나는 반면, 니켈 이온은 -1.19V (vs. SCE)에서 전착이 발생한다. 따라서, 단일 도금욕조 내에서 Ni-Cu 합금도금층을 제조하기 위해서는 두 금속 이온종 간의 전위차를 줄여주어야 하는데, 이를 위해 본 연구에서는 $Na_3C_6H_5O_7{\cdot}2H_2O$를 착화제로 사용하였다. 다양한 Ni-Cu 합금 도금층의 조성을 얻기 위하여 기본 도금욕 내 황산니켈과 황산구리의 비율을 10:1로 설정하였다. 도금 공정 조건에 따른 합금 도금층 조성 변화를 관찰하기 위하여 도금액 pH와 교반 속도에 따른 도금층 조성 변화를 분석하였으며, 도금액의 UV-VIS과 도금층의 XRD 와 SEM 측정을 통하여 도금욕과 도금층 간의 상관 관계를 유추하였다. 본 도금액에 사용된 $Na_3C_6H_5O_7{\cdot}2H_2O$ 착화제의 효과는 pH3에서 가장 현저하였으며, pH 변화 및 교반 속도 변화를 이용하여 다양한 합금 조성을 얻을 수 있었다.

• Membrane Journal
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• v.34 no.2
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• pp.146-153
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• 2024

In this experiment, a Ti-based flat hydrogen separation membrane was designed and manufactured. In order to find a Ti-based hydrogen separation membrane of a new composition, the correlation between the physical-chemical properties and hydrogen permeability of various alloys was investigated. Based on this, two types of new alloy films (Ti_14.2Zr_66.4Ni_12.6Cu_6.8 (70 ㎛), Ti_17.3Zr_62.7Ni₂₀ (80 ㎛)) was designed and manufactured. The manufactured flat hydrogen separation membrane was tested for hydrogen permeation using mixed gas (H₂, N₂) and sweep gas (Ar) at 300~500℃ and 1~4 bar. The Ti_14.2Zr_66.4Ni_12.6Cu_6.8 alloy film has a maximum flux of 16.35 mL/cm² min at 500℃ and 4 bar, and the Ti_17.3Zr_62.7Ni₂₀ alloy film has a maximum flux of 10.28 mL/cm² min at 450℃ and 4 bar.

• Journal of Korea Foundry Society
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• v.17 no.5
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• pp.443-449
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• 1997

The purpose of this study is to investigate the effect of P addition and homogenizing heat treatment on the mechanical properties of Cu-Sn-Ni alloy. The addition of P was 0.025wt.%P to 0.085wt.%P and homogenizing heat-treated at 400, 500, $600^{\circ}C$ under $N_2$ gas atmosphere. Mechanical properties was investigated in this study were Rockwell hardness, tensile strength, and elongation. Tensile strength and elongation increased with P and homogenizing time. Temperature was significantly influence on mechanical properties. Hardness decreased with increasing homogenizing time and temperature, but 0.085wt.%P specimen was showed higher hardness and lower tensile strength and elongation than 0.073wt.%P specimen due to the presence of more $Cu_3P$ in matrix.

• Korean Journal of Materials Research
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• v.27 no.11
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• pp.624-630
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• 2017

In this study, we investigated the overpotential of precipitation related to the catalytic activity of electrodes on the initial process of electrodeposition of Co and Co-Ni alloys on polycrystalline Cu substrates. In the case of Co electrodeposition, the surface morphology and the magnetic property change depending on the film thickness, and the relationship with the electrode potential fluctuation was shown. Initially, the deposition potential(-170 mV) of the Cu electrode as a substrate was shown, the electrode potential($E_{dep}$) at the $T_{on}$ of electrodeposition and the deposition potential(-600 mV) of the surface of the electrodeposited Co film after $T_{off}$ and when the pulse current was completed were shown. No significant change in the electrode potential value was observed when the pulse current was energized. However, in a range of number of pulses up to 5, there was a small fluctuation in the values of $E_{dep}$ and $E_{imm}$. In addition, in the Co-Ni alloy electrodeposition, the deposition potential(-280 mV) of the Cu electrode as the substrate exhibited the deposition potential(-615 mV) of the electrodeposited Co-Ni alloy after pulsed current application, the $E_{dep}$ of electrodeposition at the $T_{on}$ of each pulse and the $E_{imm}$ at the $T_{off}$ varied greatly each time the pulse current was applied. From 20 % to less than 90 % of the Co content of the thin film was continuously changed, and the value was constant at a pulse number of 100 or more. In any case, it was found that the shape of the substrate had a great influence.

• Korean Journal of Materials Research
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• v.19 no.12
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• pp.667-673
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• 2009

The electrocatalytic characteristics of oxygen reduction reaction of the $PtxM_{(1-x)}$ (M = Co, Cu, Ni) supported on multi-walled carbon nanotubes (MWNTs) have been evaluated in a Polymer Electrolyte Membrane Fuel Cell (PEMFC). The $Pt_xM_{(1-x)}$/MWNTs catalysts with a Pt : M atomic ratio of about 3 : 1 were synthesized and applied to the cathode of PEMFC. The crystalline structure and morphology images of the $Pt_xM_{(1-x)}$ particles were characterized by X-ray diffraction and transmission electron microscopy, respectively. The results showed that the crystalline structure of the Pt alloy particles in Pt/MWNTs and $Pt_xM_{(1-x)}$/MWNTs catalysts are seen as FCC, and synthesized $Pt_xM_{(1-x)}$ crystals have lattice parameters smaller than the pure Pt crystal. According to the electrochemical surface area (ESA) calculated with cyclic voltammetry analysis, $Pt_{0.77}Co_{0.23}$/MWNTs catalyst has higher ESA than the other catalysts. The evaluation of a unit cell test using Pt/MWNTs or $Pt_xM_{(1-x)}$/MWNTs as the cathode catalysts demonstrated higher cell performance than did a commercial Pt/C catalyst. Among the MWNTs-supported Pt and $Pt_xM_{(1-x)}$ (M = Co, Cu, Ni) catalysts, the $Pt_{0.77}Co_{0.23}$/MWNTs shows the highest performance with the cathode catalyst of PEMFC because they had the largest ESA.

• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.106-114
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• 1992

Abstract-Quantitative surface analysis of Co-Ni and Au-Cu alloys by XPS and SIMS was studied. For Co-Ni alloy, quantitative XPS analysis could be done within 1-2% relative error with pure element standards without any correction. For Au-Cu, quantitative XPS analysis was not possible without any correction. But it could be done with standard alloys of various composition within 1-2% relative error. Without standard alloys, Au-Cu alloys could be analyzed by XPS within 10% relative error with pure element standards. For SIMS analysis of Co-Ni alloys, the relative secondary ion yields of Co+/Nit has linear relation with ratio of each composition so that quantitative SIMS analysis was possible for Co-Ni alloys. Preliminary results of XPS round robin test of VAMAS-SCA Japan Project are given.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.143-145
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• 2007

The correlation between crystallization and deformation behavior in the supercooled liquid region (SLR) of a $Cu_{54}Ni_{6}Zr_{22}Ti_{18}$ bulk metallic glass (BMG) alloy is investigated by compression tests, differential scanning calorimetry (DSC), electron energy loss spectrometry (EELS) and high resolution transmission electron microscopy (HRTEM). In the SLR, This BMG alloy was strongly depended on the deformation temperature and the alloy exhibits important change in deformation behavior after a given time which is directly connected to the development of crystallization. Compressive stress impeded decomposition and consequently retarded forming of nano-crystal, which led to enlarge the homogeneous deformation region of the BMG alloy in SLR during compression test.

• Journal of the Korean Magnetics Society
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• v.20 no.4
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• pp.129-133
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• 2010

Two-layered ferromagnetic alloy films (NiFe, CoFe) with a Conetic (NiFeCuMo) intermediately soft magnetic layer of different thickness were investigated to correlate the coercivity values and magnetization process with the strength of saturation field of hard axis. Thickness dependence of the $H_{EC}$ (coercivity of easy axis), $H_{HS}$ (saturation field of hard axis.), and X (susceptibility) of NiFe and NiFeCuMo thin films for the glass/Ta(5 nm)/[CoFe or NiFe(5 nm-t/2)]/NiFeCuMo(t = 0, 4, 6, 8, 10 nm)/[CoFe or NiFe(5 nm-t/2)]/Ta(5 nm) films prepared by the ion beam deposition method was measured. The magnetic properties $H_{EC}$, $H_{HS}$, and X of two-layered ferromagnetic CoFe, NiFe films with a NiFeCuMo intermediately super-soft magnetic layer were strongly depended on the thickness of NiFeCuMo layer. The value of the coercivity and magnetic susceptibility of the NiFeCuMo film decreased by 25% and doubled relative to that of the NiFe film.

• Transactions of the Korean hydrogen and new energy society
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• v.4 no.1
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• pp.41-50
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• 1993

The hydrogen absorption and desorption characteristics of microencapsulated (CFM)$Ni_{4.7}Al_{0.2}Fe_{0.1}$ and $MmNi_4Fe$ powder with Ni and/or Cu by means of chemical plating method have been investigated. Initial hydrogen absorption rate and activation property were increased remarkably by encapsulation and subsequent compacting. Pellets abtained by compacting of Cu-encapsulated fine powder have fairly good strength even after 30 cycles of hydriding and dehydriding. Encapsulated alloy powder and their compacts show a good resistance to degradation by $O_2$ or CO in hydrogen.