• Journal of the Korean institute of surface engineering
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• v.43 no.5
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• pp.248-254
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• 2010

Porous $Al_2O_3$ film can be utilized as template for fabrication of nano-structured materials. Porous anodic alumina layer as template was prepared by anodization of aluminum in oxalic acid, and the pore diameter and barrier-type alumina layer can be controlled for proper anodizing parameter by widening process in $H_3PO_4$ solution. The $SiO_2$ nanodot and Ni nanowire was fabricated using anodic alumina template and their characteristics were investigated using SEM and TEM with EDS. Especially the growth mechanism of $SiO_2$ nanodot in alumina membrane compared with thinning of the alumina barrier layer during anodization was also investigated.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.66.2-66.2
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• 2018

금속의 양극산화 공정(anodizing)은 전해질 내 금속에 인위적으로 전위를 가해 금속 표면에 얇은 산화막(oxide layer)을 형성하여 금속의 내식성, 내마모성을 증가시키는 공정이다. 타이타늄은 가볍고 단단하여 산업분야에 유용하게 사용되며 이와 같은 양극산화 공정을 통해 내식성, 내마모성을 크게 높일 수 있다. 본 연구에서는 항공기 부품용 타이타늄의 최적 양극산화 조건을 찾기 위해 전압의 파형, 전해액의 조성에 따라 양극산화 실험을 진행하였다. SEM, AFM, EDS, 분광측색계, 색채색차계 등을 이용하여 각 조건에 해당하는 타이타늄의 산화막($Tio_2$)의 두께, crack 형태, pore 형태, 균일도, 표면 조도, 내전압, 색 수치를 분석하였다. 그 결과 전압 DC 140 V, 주성분이 KOH $Na_3PO_4{\cdot}12H_2O$인 전해액으로 이루어진 양극산화 조건에서 가장 균일하고 색 재현성이 우수한 타이타늄의 산화막($Tio_2$)을 형성하였다.

• Journal of the Korean institute of surface engineering
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• v.12 no.3
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• pp.167-173
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• 1979

The structure of anodic aluminium oxide films formed in 2% oxalic asid at constant temperature was studied by the oid of the transmission and replica electron microscopy. Far the initial stage of oxidations, it is observed that pores are initiated from lattice defects as subgrain boundaries, and then spread radially. Some pores merge each other and the others cease to grow until the current density reaches to the steady state. The pore diameter and the cell size are proportional to the anodizing voltages, and it is considered that the pore initiation and growth are largely controlled by the field - assisted oxide dissolution.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.162-163
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• 2014

Aluminum anodizing is a technique that can be formed pores well aligned various diameters. We were prepared CNFs using the polymer as carbon source using the AAO as a template. CNFs can be heat treated at $1400^{\circ}C$ and became soft carbon. It showed electrochemical behavior by Crystallization. In this experiment, I was observing the behavior as a anode material for LIC of CNFs having different diameters.

• Corrosion Science and Technology
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• v.7 no.3
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• pp.158-161
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• 2008

It is well known that iron is one of the most common impurity elements found in aluminum and its alloys. Iron in the aluminum forms an intermetallic compounds such as $FeAl_3$. The $FeAl_3$ particles on the aluminum surface are one of the most detrimental phases to the corrosion process and anodizing procedure for aluminum and its alloys. Trial and error surface treatment will be carried out to find the preferential and effective removal of $FeAl_3$ particles on the surfaces without dissolution of aluminum matrix around the particles. One of the preferable surface treatments for the aim of getting $FeAl_3$ free surface was an electrochemical treatment such as cathodic current density of $-2kAm^{-2}$ in a 20-30 mass% $HNO_3$ solution for the period of 300s. The corrosion characteristics of aluminum surface with $FeAl_3$ free particles are examined in a $0.1kmol/m^3$ NaCl solution. It is found that aluminum with free $FeAl_3$ particles shows higher corrosion resistance than aluminum with $FeAl_3$ particles.

• Journal of the Korean Chemical Society
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• v.64 no.3
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• pp.153-158
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• 2020

With the recent popularity of mobile devices, the demand for lithium-ion batteries is increasing. In this study, the surface treatment process for the development of the Al (aluminum) lead tab for positive electrode, a key component of the pouch-type lithium-ion battery, was investigated. Anodizing and sealing processes were tested as surface treatment techniques. It was found that only a sealing process is needed to obtain sufficient adhesive strength. In the present study, an adhesive strength of 17 N/12 mm was achieved by degreasing and etching pretreatment, followed by a sealing process of 10 min duration. This adhesive strength was greater than that achievable using Cr (chromium) surface treatment. Using various surface analysis techniques, the shape and composition of the surface before and after being subjected to the surface treatment were compared and analyzed. The results of this study are expected to contribute to the development of an eco-friendly lead tab.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.115.2-115.2
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• 2016

Al alloys are being used widely for automobile, aerospace and mechanical components because of their high strength ratio to weight. However, still they suffer from abrasion or corrosion owing to insufficient resistances to friction or mechanical impact and chemical attack. Plasma electrolytic oxidation (PEO) method is one of the promising surface treatment methods for Al alloys which can render better hardness than aluminum anodic oxide (AAO) films prepared by conventional anodizing method in acidic solutions. In this presentation, some basic nature of PEO film formation and growth process on Al alloys will be presented based on the experimental results obtained and discussed in view of dielectric breakdown and reformation and the role of various anions in film breakdown and reformation of PEO films.

• Journal of the Korean institute of surface engineering
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• v.53 no.4
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• pp.144-152
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• 2020

In the manufacturing process of joining of aluminum alloy and polymer, the strength of the metal-polymer joining is greatly influenced by the nanostructure of the oxide film. In this study, we investigated the dependence of joining strength on the thickness, structure, pore formation and surface roughness of the formed film. After the two-step anodization process, the surface oxide layer became thinner and rougher resulting in higher joining strength with the polymer. More specifically, after the two-step anodization, the surface roughness, Ra increased from 2.3 to 3.2 ㎛ with pore of three-dimensional (3D) nanostructure, and the thickness of the oxide film was thinned from 350 to 250 nm. Accordingly, the joining strength of the aluminum alloy with polymer increased from 23 to 30 MPa.

• Journal of the Korean institute of surface engineering
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• v.26 no.2
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• pp.45-54
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• 1993

In this study, magnetic properties of anodized Al film deposited with ferro-magnetic metals in the capacity of perpendicular magnetic recording media were measured and evaluated to find out the role of structure and morphology of the oxide films on magnetic characteristics. The object of this work was to present the conditions of magnetic thin film formation with more superior magnetic property. Anodizing was carried out under various conditions, and then the anodized film were electro-deposited with Co, Ni, Fe and their alloys. Coercive force and residual magnetization in perpendicular direction increased as the pore length of anodized film increased. It was attributed to the increase of the amount of depoisted metals and the ratio of length/diameter of pores. Morphology of anodized films in phosperic acid was not similar to that of sulfuric acid, and thin films in the former solution had perpendcular magnetic anisostropy because of large diameter, irregular length and distribution of the pores. It was found that magnetic properties of the thin films, which had doubled layer of two metals, were dominated by the metal electrodeposited on the surface of the anodized oxide films.

• Transactions of the Korean hydrogen and new energy society
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• v.16 no.4
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• pp.350-355
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• 2005

소형 PEMFC(Proton Exchange Membrane Fuel Cell)는 전기를 만들기 위해서 고순도의 수소를 필요로 한다. 각각의 마이크로 성형된 금속박판(스테인레스 스틸, 알루미늄)을 진공 브레이징법으로 접합하여 수소공급용 소형 개질기를 제작하였다. 마이크로 채널의 내부는 졸-겔법(스테인레스 스틸)과 양극산화법(알루미늄)으로 촉매를 지지하기 위한 다공성 $Al_2O_3$ 층을 형성시켰다. 스테인레스 스틸 박판은 에칭과 브레이징에 유리하였으나, 표면산화층 코팅을 균일하게 하여 안정적인 촉매반응을 유도하기 위한 균일한 표면 산화층 형성이 힘들었다. 반면 알루미늄 박판은 표면 산화층 형성이 상대적으로 용이했으며, 촉매를 상하지 않는 낮은 온도에서의 적층이 가능했다.