• 한국수소및신에너지학회논문집
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• 제23권6호
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• pp.573-580
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• 2012

Corrosion resistance and basic physical properties of solid tantalum are not comparable to most of the structural metallic materials. The relative high cost and melting temperature of tantalum are obstacles to be widely applied to general engineering processes. Electrodeposition in molten salt enables compact and uniform tantalum coating. In this study, Ta was coated onto base metal (SUS316L) with different current densities (0.5, 5, $20mA/cm^2$) by using MSE (Molten Salt Electrodeposition). In this study, it showed that deposition efficiency and microstructure of Ta coating layer were strongly depended on current density. In the case of the current density of $5mA/cm^2$, densest microstructure was obtained. The current density above $5mA/cm^2$ caused non-uniform microstructure due to rapid deposition rate. Dense microstructure and intact coating layer contributed to significant corrosion resistance enhancement.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.432-434
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• 2009

Metal nano-wire arrays on Cu-coated seed layers were fabricated by aqueous solution method using sulfate bath at room temperature. The seed layers were coated on Anodic aluminum oxide (AAO) bottom substrates by electrochemical deposition technique, length and diameter of metal nano-wires were dominated by controlling the deposition parameters, such as deposition potential and time, electrolyte temperature. Anodic aluminum oxide (AAO) was used as a template to prepare highly ordered Ni, Fe, Co and Cu multilayer magnetic nano-wire arrays. This template was fabricated with two-step anodizing method, using dissimilar solutions for Al anodizing. The pore of anodic aluminum oxide templates were perfectly hexagonal arranged pore domains. The ordered Ni, Fe, Co and Cu systems nano-wire arrays were characterized by Field Emission Scanning Electron Microscopy (FE-SEM) and Vibrating Sample Magnetometer (VSM). The ordered Ni, Fe, Co and Cu systems nano-wires had different preferred orientation. In addition, these nano-wires showed different magnetization properties under the electrodepositing conditions.

• 한국자기학회지
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• 제15권4호
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• pp.241-245
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• 2005

CoFeNi 합금은 HDD, MEMS 분야에서 head core 재료로 쓰이는 permalloy(FeNi)합금보다 뛰어난 우수한 자기적 특성을 가진 재료로써 최근 많이 연구되어지고 있다. CoFeNi 합금의 조성과 전기도금 시 전류조건에 따른 미세구조와 결정학적 특성이 자기 특성에 미치는 영향을 조사하였으며, 높은 포화자화와 낮은 보자력을 갖는 CoFeNi 삼원계 합금을 전기도금 방식으로 제조하는데 성공하였다. 포화자화 1.9 T, 보자력 0.16 A/m를 갖는 대표적인 CoFeNi film의 조성은 $Co_{30}\;Fe_{34}\;Ni_{36}(at\%)$이며, 미세결정립과 ffc-bcc 상의 혼재가 낮은 보자력을 갖는 요인임을 XRD, TEM의 결과로부터 확인 하였다.

• 센서학회지
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• 제30권2호
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• pp.71-75
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• 2021

Recently, transition-metal-based hydroxide materials have attracted significant attention in various electrochemical applications owing to their low cost, high stability, and versatility in composition and morphology. Among these applications, transition-metal-based hydroxides have exhibited significant potential in supercapacitors owing to their multiple redox states that can considerably enhance the supercapacitance performance. In this study, nanostructured Ni-Mn double hydroxide is directly grown on a conductive substrate using an electrodeposition method. Ni-Mn double hydroxide exhibits excellent electrochemical charge-storage properties in a 1 M KOH electrolyte, such as a specific capacitance of 1364 Fg-1 at a current density of 1 mAcm-2 and a capacitance retention of 94% over 3000 charge-discharge cycles at a current density of 10 mAcm-2. The present work demonstrates a scalable, time-saving, and cost-effective approach for the preparation of Ni-Mn double hydroxide with potential application in high-charge-storage kinetics, which can also be extended for other transition-metal-based double hydroxides.

• Bulletin of the Korean Chemical Society
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• 제23권11호
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• pp.1519-1523
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• 2002

A procedure for preparing semiconductor/metal nanowire arrays is described, based on a template method which entails electrochemical deposition into nanometer-wide parallel pores of anodic aluminum oxide films on aluminum. Aligned CdS/Co heterostructured nanowires have been prepared by ac electrodeposition in the anodic aluminum oxide templates. By varying the preparation conditions, a variety of CdS/Co nanowire arrays were fabricated, whose dimensional properties could be adjusted.

• 전기화학회지
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• 제10권2호
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• pp.94-103
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• 2007

반도체 소자의 고속화, 고집적화, 고신뢰성화에 대한 요구는 알루미늄 합금으로부터 구리로의 배선 물질의 변화를 유도하였다. 낮은 비저항과 높은 내열화성을 특징으로 하는 구리는 그 전기적, 재료적 특성이 알루미늄과 상이하여 배선 형성에 있어 새로운 주변 재료와 공법을 필요로 한다. 본 총설에서는 상감공정(damascene process)을 사용하는 다층 구리 배선 공정에 있어 핵심이 되는 구리 전해 도금(electrodeposition) 공정을 중심으로 확산 방지막(diffusion barrier) 및 도전층(seed layer), 바닥 차오름(bottom-up filling)을 위한 전해/무전해 도금용 유기 첨가제, 화학적 기계적 평탄화(chemical mechanical polishing) 및 표면 보호막(capping layer) 기술 등의 금속화 공정에 대한 개요와 개발 이슈를 소개하고 최근의 연구 결과를 통해 구리 배선 공정의 최신 연구 동향을 소개하였다.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3118-3122
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• 2010

The water soluble redox polymer, poly(N-vinylimidazole) complexed with Os(4,4'-dichloro-2,2'-bipyridine)$_2Cl]^+$ (PVI-[Os(dCl-bpy)$_2Cl]^+$), was electrodeposited on the surface of a glassy carbon electrode by applying cycles of alternating square wave potentials between 0.2 V (2 s) and 0.7 V (2 s) to the electrode in a solution containing the redox polymer. The coordinating anionic ligand, $Cl^-$ of the osmium complex, became labile in the reduced state of the complex and was substituted by the imidazole of the PVI chain. The ligand substitution reactions resulted in crosslinking between the PVI chains, which made the redox polymer water insoluble and caused it to be deposited on the electrode surface. The deposited film was still electrically conducting and the continuous electrodeposition of the redox polymer was possible. When cycles of square wave potentials were applied to the electrode in a solution of bilirubin oxidase and the redox polymer, the enzyme was co-electrodeposited with the redox polymer, because the enzymes could be bound to the metal complexes through the ligand exchange reactions. The electrode with the film of the PVI-[Os(dCl-bpy)$_2Cl]^+$ redox polymer and the co-electrodeposited bilirubin oxidase was employed for the reduction of $O_2$ and a large increase of the currents was observed due to the electrocatalytic $O_2$ reduction with a half wave potential at 0.42 V vs. Ag/AgCl.

• 한국수소및신에너지학회논문집
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• 제27권6호
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• pp.636-641
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• 2016

Alkaline water electrolysis is commercial hydrogen production technology. It is possible to operate MW scale plant. Because It used non-precious metal for electrode. But It has relatively low current density and low efficiency. In this study, research objective is development of anode for alkaline water electrolysis with low cost, high corrosion resistance and high efficiency. Stainless steel 316L (SUS 316L) was selected for a substrate of electrode. To improve corrosion resistance of substrate, Nickel (Ni) layer was electrodeposited on SUS 316L. Ni-Fe alloy was electrodeposited on the passivated Ni layer as active catalyst for oxygen evolution reaction(OER). We optimized preparation condition of Ni-Fe alloy electrodeposition by changing current density, electrodeposition time and composition ratio of Ni-Fe electrodeposition bath. This electrodes were electrochemically evaluated by using Linear sweep voltammetry (LSV) and Cyclic voltammetry (CV). The Ni-Fe alloy (Ni : Fe = 1 : 1) showed best activity of OER. The optimized electrode decreased overpotential about 40% at $100mA/cm^2$ compared with Ni anode.

• Journal of Electrochemical Science and Technology
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• 제14권1호
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• pp.75-84
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• 2023

The accumulation of spent carbide (YG8), not only pollutes the environment but also causes waste of tungsten, cobalt and other rare metal resources. To better address this issue, we proposed a combined electrochemical separation process of low-temperature aqueous solution and high-temperature molten salt for tungsten and cobalt. H₂WO₄ was obtained from spent carbide in an aqueous solution, and we calcined it to obtain WO₃, which was used as a raw material to obtain tungsten by using molten salt electrodeposition. The influence of the current efficiency and the electrochemical behavior of the discharge precipitation of W(VI) were also studied. The calcination results showed that the morphology of WO₃ was regular and there were no other impurities. The maximum current efficiency of 82.91% was achieved in a series of electrodeposition experiments. According to XRD and SEM analysis, the recovered product was high purity tungsten, which belongs to the simple cubic crystal system. In the W(VI) reduction mechanism experiments, the electrochemical process of W(VI) in NaCl-Na₂WO₄-WO₃ molten salt was investigated using linear scanning voltammetry (LSV) and chronoamperometry in a three-electrode system. The LSV showed that W(VI) was reduced at the cathode in two steps and the electrode reaction was controlled by diffusion. The fitting results of chronoamperometry showed that the nucleation mechanism of W(VI) was an instantaneous nucleation mode, and the diffusion coefficient was 7.379×10^-10 cm²·s^-1.

• 한국결정성장학회지
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• 제9권6호
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• pp.590-596
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• 1999

염화물욕 아연도금에서 순환셀 도금장치에 3전극계를 부착하여 첨가제 효과를 조사하였다. 도금액에 폴리에틸렌글리콜(이하 PEG)의 첨가는 도금 과전압을 증가시키고 수소발생을 억제하는데 이것은 첨가제에 의하여 아연 이온의 이동을 억제하거나 음극에 첨가제 흡착에 의한 것으로 생각된다. 그러나 PEG는 사용되는 도금액의 물성(전도도, 점도, 비중)에는 영향을 미치지 않는 것으로 나타났다. 도금층에 미치는 영향은 표면 조도가 개선되고, 광택도가 감소된다. 이러한 영향은 PEG 분자수가 클수록 증가되나 분자수가 다른 PEG의 혼합첨가제에서는 광택도 감소가 줄어든다. 이러한 것은 도금층 결정면의 방향성, 입자의 크기 및 형태가 PEG 분자 수에 따라 다르게 나타나는 것에 기인하는 것으로 판단된다.