• Journal of Electrochemical Science and Technology
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• 제14권4호
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• pp.377-387
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• 2023

Ni-W/Al₂O₃ nano-composites were electrodeposited on mild steel substrate for mechanical and corrosion resistance applications. This study focused on the preparation of Ni-W/Al₂O₃ nano-composite coating with various quantity of Al₂O₃ incorporations. The addition of Al₂O₃ in the electrolytes were varied from 1-10 g/L in electrolytes and the Al₂O₃ incorporation in Ni-W/Al₂O₃ nano-composite coatings were obtained from 1.82 to 13.86 wt.%. The incorporation of Al₂O₃ in Ni-W alloy matrix influenced the grain size, surface morphology and structural properties were observed. The distributions of Al₂O₃ particle in alloy matrix were confirmed using electron microscopy (FESEM and TEM) and EDAX mapping analysis. The crystal structure informations were studied using X-ray diffraction method and it confirms that the deposits having cubic crystal structure. The better corrosion rate (0.87 mpy) and microhardness (965 HV) properties were obtained for the Ni-W/Al₂O₃ nano-composite coating with 13.86 wt.% of Al₂O₃ incorporations.

• 한국표면공학회지
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• 제39권5호
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• pp.210-214
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• 2006

In order to enhance the electromagnetic shielding efficiency of commercialized cold-rolled steel sheets, we have prepared Ni deposited steel sheets by the electrodeposition method. Surface alloying with Ni and Fe was achieved on a steel sheet by diffusion annealing process. Shielding effectiveness measurement results showed that annealed Ni electrodeposited steel sheets enhanced the shielding efficiency up to about 3 dB in the frequency range of 20 to 200Hz, compared with that of non-deposited steel sheets.

• 한국표면공학회지
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• 제36권3호
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• pp.242-250
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• 2003

Electrodeposition of Ni was carried out on copper substrate from Ni Sulfamate bath by DC and high frequency pulse current. During the electroplating, bath temperature was steady $60^{\circ}C$ , agitation was applied. Morphology and surface roughness of electrodeposits was investigated with the AFM. Crystalline structure of electrodeposits was investigated with XRD. Also, surface electric resistivity was investigated with 4-point probe. The result of crystalline structure by X-ray diffractometer, in the case of DC, <200> direction was dominant growing direction. But in the case of PC, the ratio of <200> direction vs. other direction decreased. As the pulse frequency increased, the enhanced properties of deposits were shown. With increasing frequency, the degree of surface properties increased DC more than that of PC, eg surface morphology, roughness and the degree of compactness of grains. With increasing duty cycle, the surface properties such as the degree of the morphology, roughness and electroconductivity was deteriorated.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2012년도 춘계학술발표회 논문집
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• pp.308-308
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• 2012

Electrodeposition of thermoelectric materials, including binary and ternary compounds, have been attracting attentions, because its many advantages including cost-effectiveness, rapid deposition rate, and ease of control their microstructure and crystallinity by adjusting electrodeposition parameters. In this work, $Bi_xTe_y$ films were potentiostatically electrodeposited using Au/Ni(80/20 nm)/Si substrate as the working electrode in solutions consisting of 10mM $TeO_2$ and 1M $HNO_3$ where $Bi(NO_3)_3$ was varied from 2.5 to 10 mM. Prior to electrodeposition potentiostatically, linear sweep voltammograms (LSV) were acquired with a standard three-electrode cell. The $Bi_xTe_y$ films deposited using the electrolyte containing low Bi ions shows p-type conductivity, which might be attributed by the large incorporation of Te phases. Near stoichiometric $Bi_2Te_3$ thin films were obtained from electrolytes containing 5mM $Bi(NO_3)_3$. This film shows the maximum Seebeck coefficient of $-100.3{\pm}12.7{\mu}V/K$. As the increase of Bi ions in electrolytes decreases the Seebeck coefficient and resistivity. The maximum power factor of $336.2{\mu}W/m{\cdot}K^2$ was obtained from the film deposited using the solution of 7.5mM $Bi(NO_3)_3$.

• 한국진공학회지
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• 제16권2호
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• pp.79-90
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• 2007

저에너지 초고속 표면 처기 이온원, 4개의 마그네트론 스퍼터 캐소드가 부착된 300 mm 폭 다목적 연성 기판 제작을 위한 부피 800 L 용량의 진공 웹코터 원형 (prototype) 장비를 설계 제작하였고, 무접착제 2층 연성 동박 적층 필림을 제작하여 성능을 평가하였다. 2 개의 터보 펌프 및 폴리콜드를 장착한 비코팅 부분인 상실부와 각각 1개씩의 터보 펌프를 사용한 표면 처리 및 코팅 부분인 하실부의 진공 배기 특성을 측정하였다. 패러데이 컵을 사용하여 대면적 이온원의 이온 전류 밀도 및 균일도를 측정하고, 스퍼터 캐소드의 자기장 분포 및 타겟 사용 효율을 조사하였다. 진공 웹코터의 성능 및 각 구성 요소의 특성 조사를 위하여 연성 기판으로는 폴리이미드 (Kapton-E) $38{\mu}m$을 사용하여 여러 가지 가스 이온에 대한표면 처리 조건에 따른 증류수의 접촉각 변화와 화학 성분의 변화를 x-선 분광학을 사용하여 조사하였다. 고밀도 2층 연성 동박 적층 필림 기판을 스퍼터-전기 도금법으로 제작하기 위하여 스퍼터 타겟으로는 Ni-Cr 및 Cu 금속을 사용하여, 각각의 증착율을 직류 전력의 변화 및 롤의 속도에 따라 조사하였고, 전기 도금으로 $9{mu}m$ 까지 동박 적층 필림을 제작한 후 접착력 및 내열성, 내화학성을 측정하여 소형 진공 웹 코터의 특성을 조사하였다.