In order to apply to high-nickel cathodes for high-capacity and stability enhancement of lithium-ion batteries, the characteristics of the coating film were reviewed using the conventional nickel plating method. The surface morphology of the plating layer and the measurement of the surface roughness were analyzed according to scan size and rate using the contact mode of Atomic Force Microscopy. The hydrogen ion concentration (pH) of the electrolyte played an important role in shaping the metal ion plating. As the overpotential of the surface increased during plating, the crystals grew in a direction other than the main crystal growth direction. The increase in on-time during pulse plating appears to result in coarse particles as much of the applied current is consumed by the reduction of hydrogen ions, resulting in lower current efficiency. From the AFM image, it was confirmed that the blackening of the plated film was due to a partial overvoltage phenomenon during electrolytic degreasing. In order to be used as a high-nickel cathode, it seems that the current must be uniformly distributed on the surface of the substrate during plating.

Transparent conducting electrodes are essential components in various optoelectrical devices. Although indium tin oxide thin films have been widely used for transparent conducting electrodes, silver nanowire network is a promising alternative to indium tin oxide thin films owing to its lower processing cost and greater suitability for flexible device application. In order to widen the application of silver nanowire network, the electrical conductance has to be improved while maintaining high optical transparency. In this study, we report the enhancement of the electrical conductance of silver nanowire network transparent electrodes by copper electrodeposition on the silver nanowire networks. The electrodeposited copper lowered the sheet resistance of the silver nanowire networks from 21.9 Ω/□ to 12.6 Ω/□. We perform detailed X-ray diffraction analysis revealing the effect of the amount of electrodeposited copper-shell on the sheet resistance of the core-shell(silver/copper) nanowire network transparent electrodes. From the relationship between the cross-sectional area of the copper-shell and the sheet resistance of the transparent electrodes, we deduce the electrical resistivity of electrodeposited copper to be approximately 4.5 times that of copper bulk.

Hot-press forming(HPF) steel can be applied successfully to auto parts because of its superior mechanical properties. However, its resistances to aqueous corrosion and the subsequent hydrogen embrittlement(HE) decrease significantly when the steel is exposed to corrosive environments. Considering that the resistances are greatly dependent on the properties of coating materials formed on the steel surface, the characteristics of the corrosion and hydrogen diffusion behaviors regarding the types of coating material should be clearly understood. Electrochemical polarization and impedance measurements reveal a higher corrosion potential and polarization resistance and a lower corrosion current of the Al-coating compared with Zn-coating. Furthermore, it was expected that the diffusion kinetics of the hydrogen atoms would be much slower in the Al-coating, and this would be due mainly to the much lower diffusion coefficient of hydrogen in the Al-coating with a face-centered cubic structure. The superior surface inhibiting effect of the Al-coating, however, is degraded by the formation of local cracks in the coated layer under severe stress conditions, and therefore further study will be necessary to gain a clearer understanding of the effect of cracks formed on the coated layer on the subsequent corrosion and hydrogen diffusion behaviors.

We performed this study to understand the effect of a single-crystalline anode on the mechanical properties of asdeposited films during electrochemical deposition. We used a (111) single- crystalline Cu plate as an anode, and Si substrates with Cr/Au conductive seed layers were prepared for the cathode. Electrodeposition was performed with a standard 3-electrode system in copper sulfate electrolyte. Interestingly, the grain boundaries of the as-deposited Cu thin films using single-crystalline Cu anode were not distinct; this is in contrast to the easily recognizable grain boundaries of the Cu thin films that were formed using a poly-crystalline Cu anode. Tensile testing was performed to obtain the mechanical properties of the Cu thin films. Ultimate tensile strength and elongation to failure of the Cu thin films fabricated using the (111) single-crystalline Cu anode were found to have increased by approximately 52 % and 37%, respectively, compared with those values of the Cu thin films fabricated using apoly-crystalline Cu anode. We applied ultrasonic irradiation during electrodeposition to disturb the uniform stream; we then observed no single-crystalline anode effect. Consequently, it is presumed that the single-crystalline Cu anode can induce a directional/uniform stream of ions in the electrolyte that can create films with smeared grain boundaries, which boundaries strongly affect the mechanical properties of the electrodeposited Cu films.

Silicon-based thin film was prepared at room temperature by an electrochemical deposition method and a feasibility study was conducted for its use as an anode material in a rechargeable lithium battery. The growth of the electrodeposits was mainly concentrated on the surface defects of the Cu substrate while that growth was trivial on the defect-free surface region. Intentional formation of random defects on the substrate by chemical etching led to uniform formation of deposits throughout the surface. The morphology of the electrodeposits reflected first the roughened surface of the substrate, but it became flattened as the deposition time increased, due primarily to the concentration of reduction current on the convex region of the deposits. The electrodeposits proved to be amorphous and to contain chlorine and carbon, together with silicon, indicating that the electrolyte is captured in the deposits during the fabrication process. The silicon in the deposits readily reacted with lithium, but thick deposits resulted in significant reaction overvoltage. The charge efficiency of oxidation (lithiation) to reduction (delithiation) was higher in the relatively thick deposit. This abnormal behavior needs to clarified in view of the thickness dependence of the internal residual stress and the relaxation tendency of the reaction-induced stress due to the porous structure of the deposits and the deposit components other than silicon.

Simultaneous Ni and C codeposition by electrolysis was investigated with the aim of obtaining better corrosionresistivity and surface conductivity of a metallic bipolar plate for application in fuel cells and redox flow batteries. The carboncontent in the Ni-C composite plate fell in a range of 9.2~26.2at.% as the amount of carbon in the Ni Watt bath and theroughness of the composite were increased. The Ni-C composite with more than 21.6at.% C content did not show uniformlydispersed carbon. It also displayed micro-sized defects such as cracks and crevices, which result in pitting or crevice corrosion.The corrosion resistance of the Ni-C composite in sulfuric acid is similar with that of pure Ni. Electrochemical test results suchas passivation were not satisfactory; however, the Ni-C composite still displayed less than 10−4A/cm2 passivation currentdensity. Passivation by an anodizing technique could yield better corrosion resistance in the Ni-C composite, approaching thatof pure Ni plating. Surface resistivity of pure Ni after passivation was increased by about 8% compared to pure Ni. On theother hand, the surface resistivity of the Ni-C composite with 13at.% C content was increased by only 1%. It can be confirmedthat the metal plate electrodeposited Ni-C composite can be applied as a bipolar plate for fuel cells and redox flow batteries.

Electrochemical deposition characteristics of CdSe nanorods were investigated for hybrid solar cell applications. CdSe nanorods were fabricated by electrochemical method in CdSO4 and H2SeO3 dissolved aqueous solution using an anodic aluminum oxide (AAO) template. Uniformity of CdSe nanorods was dependent on the diameter and the height of holes in AAO. The current density, current mode, bath composition and temperature were controlled to obtain a 1:1 atomic composition of CdSe. CdSe nanorods deposited by direct-current method showed better uniformity compared to those deposited by purse-current and/or purse-reverse current methods due to the bottom-up filling characteristics. H2SeO3 concentration showed more significant effects on pH of solution and stoichiometry of deposits compared to that of CdSO4. A 1:1 stoichiometry of uniform CdSe nanorods was obtained from 0.25M CdSO4-5 mM H2SeO3 electrolytes with a direct current of 10 mA/cm2 at room temperature. X-ray diffraction and electron diffraction pattern investigations demonstrate that CdSe nanorods are a uniform cubic CdSe crystal.

Ag-Cu alloy nano powders were fabricated by the electrical explosion of Cu-plated Ag wires. Ag wires of 0.2mm diameter was electroplated to final diameter of 0.220 mm and 0.307 mm which correspond to Ag-27Cu and Ag-68Cu alloy. The explosion product consisted of equilibrium phases of and -Cu. The particle size of Ag-Cu nano powders were 44 nm and 70 nm for 0.220 mm and 0.307 mm wires, respectively. The Ag-Cu nano powders contained less Cu than average value due to higher sublimation energy compared to that of Ag. As a result, micron-sized spherical particles formed from liquid droplets contained higher Cu content.

Cu-Zn alloy nano powders were fabricated by the electrical explosion of Zn-electroplated Cu wire along with commercial brass wire. The powders exploded from brass wire were composed mainly of phases while those from electroplated wires contained additional Zn-rich phases as , and Zn. In case of Zn-elec-troplated Cu wire, the mixing time of the two components during explosion might not be long enough to solidify as the phases of lower Zn content. This along with the high vapor pressure of Zn appears to be the reason for the observed shift of explosion products towards the high-Zn phases in electroplated wire system.

Al-Cu alloy nano powders were produced by the electrical explosion of Cu-plated Al wires. The composition and phase of the alloy could be controlled by varying the thickness of Cu deposit on Al wire. When the Cu layer was thin, Al solid solution and were the major phases. As the Cu layer becomes thicker, Al diminished while phase prevailed instead. The average particle size of Al-Cu nano powders became slightly smaller from 63 nm to 44 nm as Cu layer becomes thicker. The oxygen content of Al-Cu powder decreased linearly with Cu content. It is well demonstrated that the electrodeposition combined with wire explosion could be simple and economical means to prepare variety of alloy and intermetallic nano powders.

In this paper, we proposed the optimal process conditions on the electro-gilding process. The responses are plating thickness and Sn proportion. The factors are temperature, current density, and addition. We minimized the total number of experiments based on the principle of dividing into small part. We grouped the factors using the plating process information which we already knew. We did Hull Cell test to find relationship between plating solution and electric effects, and applied ANOVA and RSM to estimate the optimal process conditions.

In this paper, we proposed the optimal process conditions on the electro-gilding process. The responses are plating thickness and Sn proportion. The factors are temperature, current density, and addition. We minimized the total number of experiments based

도금산업은 국가 핵심역량 사업분야인 전기재료 및 전자 부품 산업등과 밀접한 관계를 가지고 있는 산업분야일 뿐만 아니라, 핵심 부품 및 소재의 기능적 특성과 부가가치를 향상시켜 가격을 결정하는 품질에 큰 영향을 미치는 기반 산업이지만 배출 폐수에는 중금속 이외에도 맹독성 물질인 시안화물과 주요 오염물질이 대량 포함되어 있어 주요 유해물질 배출 관리 대상 업종으로 분류되어 집중 관리되고 있는 실정이다. 이에 소규모 국내 도급업체는 공동 폐수처리장을 통해 폐수를 처리하고 있으나, 도금방법이나 폐수의 특성에 따라 분리 배출되어지지 않고 대부분 통합 배출되어짐으로 인해 처리공정이 복잡하고 처리시설이 방대해지며 많은 처리비용이 소요되고 있어 도급산업을 위축시키는 원인으로 지목되고 있다. 최근 이러한 문제의 해결을 통해 도금산업을 강화하고자 이온성 물질을 분리해 정제할 수 있는 전기투석 기술을 이용한 다양한 연구가 진행되고 있다. 본 연구에서는 전기투석 장치를 이용하여 도금폐수내 구리와 니켈의 제거성능을 평가하였다. 전기투석장치의 이온교환막은 Astom사의 NEOSEPTA를 이용하였고 총 5쌍의 음이온 교환막과 양이온 교환막으로 구성된 스택을 제작하였다. NaCl을 이용하여 TDS 4,000mg/L, 니켈과 구리의 농도를 각각 20mg/L로 제조한 합성폐수를 이용하여 실험한 결과, 한계전류 12v와 25분의 체류시간 조건에서 구리와 니켈은 모두 99%이상 제거되었다. 또한 동일조건에서 유량이 증가할수록 구리와 니켈의 제거효율도 증가하는 경향을 나타내었다. 이온교환막의 변경에 따른 처리성능을 평가한 결과, 이온교환막의 종류에 따라 처리성능에 차이를 나타내어 추가적인 연구가 필요한 것으로 판단된다.