• 한국표면공학회지
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• 제56권2호
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• pp.115-124
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• 2023

Anodization is an electrochemical process that electrochemically converts a metal surface into an oxide layer, resulting in enhanced corrosion resistance, wear resistance, and improved aesthetic appearance. Local anodization, also known as selective anodization, is a modified process that enables specific regions or patterns on the metal surface to undergo anodization instead of the entire surface. Several methods have been attempted to produce oxide layers via localized anodic oxidation, such as using a mask or pre-patterned substrate. However, these methods are often intricate, time-consuming, and costly. Conversely, the direct writing or patterning approach is a more straightforward and efficient way to fabricate the oxide layers. This review paper intends to enhance our comprehension of local anodization and its potential applications in various fields, including the development of nanotechnologies. The application of anodization is promising in surface engineering, where the anodic oxide layer serves as a protective coating for metals or modifies the surface properties of materials. Furthermore, anodic oxidation can create micro- and nano-scale patterns on metal surfaces. Overall, the development of efficient and cost-effective anodic oxidation methods is essential for the advancement of various industries and technologies.

• Journal of Magnetics
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• 제11권3호
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• pp.135-138
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• 2006

We studied local anodization on permalloy $(Ni_{80}Fe_{20})$ thin film with an atomic force microscope (AFM), which was performed by applying a voltage between the permalloy sample and conductive AFM tip. Comparing with anodization on Si (100) substrate, nano-structures on the permalloy thin film was fabricated with low processability.In order to improve the processability on the permalloy thin film, we used dot-fabrication method, thatis, a conductive AFM probe was kept at a position on the film during the anodization process.

• Bulletin of the Korean Chemical Society
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• 제32권10호
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• pp.3730-3734
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• 2011

The degree of self-assembly and the size variation of nanotubular structures in anodic titanium oxide prepared by the anodization of titanium in ethylene glycol containing 0.25 wt % $NH_4F$ at 40 V were investigated as a function of anodization time. We found that the degree of self-assembly and the size of the nanotubes were strongly dependent on thickness deviation and thus indirectly on anodization time, as the thickness deviation was caused by the dissolution of the topmost tubular structures at local areas during long anodization. A large deviation in thickness led to a large deviation in the size and number of nanotubes per unit area. The dissolution primarily occurred at the bottoms of the nanotubes ($D_{bottom}$) in the initial stage of anodization (up to 6 h), which led to the growth of nanotubes. Dissolution at the tops ($D_{top}$) was accompanied by $D_{bottom}$ after the formed structures contacted the electrolyte after 12 h, generating the thickness deviation. After extremely long anodization (here, 70 h), $D_{top}$ was the dominant mode due to increase in pH, meaning that there was insufficient driving force to overcome the size distribution of nanotubes at the bottom. Thus, the nanotube array became disorder in this regime.

• 전기화학회지
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• 제9권2호
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• pp.84-88
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• 2006

본 연구에서는 주사탐침현미경을 이용한 Si 표면의 국부 산화피막 형성에 있어서, 탐침이 움직이면서 생기는 $SiO_2$의 일차원적인 선의 높이가 탐침 전위, deflection setpoint, 탐침 속도에 의해 어떻게 영향을 받는지 고찰해 보았다. -3 V 보다 작은 탐침 전위에서는 국부 산화피막 형성이 관찰되지 않았으며 -3 V 보다 큰 탐침 전위에서는, 탐침 속도가 $1{\mu}m/s$일 때, 1 V씩 증가함에 따라 0.47nm의 비율로 선의 높이가 높아졌다. Deflection setpoint는 탐침이 가하는 기계적인 힘의 표지가 되는데, $12\sim18nN$ 정도의 힘이 가해지지 않으면 국부 산화피막 형성이 관찰되지 않았다. 그 이상의 힘이 가해져야 국부 산화피막 형성이 관찰되는데 이때 선의 높이는 기계적인 힘과 무관하였다. 탐침 속도가 빨라짐에 따라 선의 높이는 낮아졌으나, 탐침 전위가 -5V인 경우, 0.7nm 이하로 낮아지지는 않았다.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.463-466
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• 2011

In this work, we investigate anodization of Pb in ethylene glycol containing small amount of $NH_4F$, demonstrating that ${\beta}-PbF_2$ particles with octahedral morphology can be prepared by adjusting the applied potential and anodizing time. FE-SEM images and XRD measurements of anodic nanostructures as a function of anodizing time clearly show that PbO is first formed on Pb. Subsequently, a local dissolution of PbO leads to formation of skeleton structure of PbO, releasing $Pb^{2+}$ ions in the electrolyte. The lead ions can be precipitated on the walls or intersection of the skeleton walls when the concentration of lead ions is saturated. The method described in this article shows the feasibility of formation of metal fluoride crystal by anodization of metal in a fluoride containing solution.

• 대한의용생체공학회:의공학회지
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• 제21권3호
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• pp.273-277
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• 2000

순 티타늄(공업용 순 티타늄, 2급)의 0.5M에서 0.7M 농도의 $H_3PO_4$ 용액에서 $0.3\~l.0 A/dm^2$의 정전류 밀도변화에 따른 anodizing 거동을 관찰하였다. 이때 형성된 산화피막을 SEM과 XRD로 관찰, 분석하였다. 실험결과 0.05M $H_3PO_4$ 용액의 조건에서 전압-시간 (V-T)곡선의 초기에는 직선적인 관계를 보였고, 전류밀도가 증가함에 따라 포물선의 형태를 나타내었다. 그리고 V-T곡선의 형태는 전해질의 농도의 증가에 따라 큰 변화가 없었지만, 최종적인 전압은 감소하였다. 티타늄의 산화피막은 전해질 농도와 전류밀도가 증가할수록 미세한 입자 형태에서 눈꽃과 같고 층을 이룬 입자들로 구성된 구조를 나타내었다. 산화막과 전해질의 계면에서의 방전에 의해 산화피막의 국소적인 침착과 용해를 동반하였다. 산화피막의 결정성은 anodizing 전압이 증가할수록 증가하였고 전해질의 농도가 증가할수록 감소하는 경향을 보였다.