• Journal of the Korean institute of surface engineering
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• v.53 no.1
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• pp.15-21
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• 2020

In this study, growth and burning behavior of 6061 aluminum alloy was studied under constant anodic voltages at various temperatures and magnetic stirring rates in 20% sulfuric acid solution by analysing I-t curves, measuring thickness and hardness of aluminum anodic oxide (AAO) films, observations of surface and cross-sectional images of AAO films. AAO films were grown continuously at lower voltages than 18.5V but burning occurred when a voltage more than 19V was applied in 20% H₂SO₄ solution at 20±0.5℃ and 200 rpm of magnetic stirring. The burning was always related with an extremely large increase of anodic current density with anodizing time, suggesting that high heat generation during anodizing causes deteriorations of AAO films by chemical reaction with acidic solutions. The burning resulted in decreases of film thickness and hardness, surface color brightened and formation of porous defects in the AAO films. The burning voltage was found to decrease with increasing solution temperature and decreasing magnetic stirring rate. The decreased burning voltages seem to be closely related with increased chemical reactions between AAO films and hydrogen ions.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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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.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.482-484
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• 2008

Anodic aluminum oxide (AAO) which prepared with two-step anodizing method (with dissimilar solutions) was used as a template to fabricate highly ordered, free standing metal nano-rods. AAO nano-template technique can realize self-organized hexagonal pore structure with nanometer dimension size, it's easy to control pore diameter, length and density by varying anodizing conditions. Ni and Ni/Fe/Cu multi-metal layer nanorods were electrochemically deposited into AAO nano-template by AC voltage in simple sulfate solutions.. The properties of samples are tested by X-ray diffraction (XRD), field emission microscopy (FE-SEM).

• Journal of the Korean institute of surface engineering
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• v.51 no.6
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• pp.393-399
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• 2018

Formation behavior of aluminum anodic oxide (AAO) films on Al6061 alloy was studied in view of thickness, morphology and defects in the anodic films in 20 vol.% sulfuric acid solution at a constant current density of $40mA/cm^2$, using voltage-time curve, observation of anodized specimen colors and surface and cross-sectional morphologies of anodic films with anodization time. With increasing anodizing time, voltage for film formation increased exponentially after about 12 min and its increasing rate decreased after 25 min, followed by a rapid decrease of the voltage after about 28 min. Surface color of anodized specimen became darker with increasing anodizing time up to about 20 min, while it appeared to be brighter with increasing anodizing time after 20 min. The darkened and brightened surfaces with anodizing time are attributed to an increase in thickness of porous anodic oxide film and a chemical damage of the films due to heat generated by increased resistance of the film, respectively. Cross-sectional observation of AAO films revealed the formation of defects of crack shape at the metal/oxide interface after 15 min which prevents the growth of AAO films. Width and length of the crack-like defect increased with anodizing time up to 25 min of anodizing, and finally the outer part of AAO films was partly dissolved or detached after 30 min of anodizing, resulting in non-uniform surface structures of the AAO films.

• Journal of the Korean institute of surface engineering
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• v.50 no.6
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• pp.427-431
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• 2017

Anodic aluminum oxide (AAO) film has recently attracted much attention as a key material for the fabrication of various nanostructures. A control of anodizing voltage (U) was employed to render different anodic aluminum oxide (AAO) nanostructures with pore diameter ($D_p$) and interpore distance ($D_{int}$) in oxalic acid. In this work, we study the effect of stepwise modulation of anodizing voltages on the shape and dimension of porous structures along the vertical direction and demonstrate the fabrication of hierarchical layers of systematically controlled three-dimensional (3D) pore profile.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.33-33
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• 2011

반도체 산업기술이 발달함에 따라 고청정 공정 환경이 요구되고 있으며, 반도체 공정용 장비에 이용되는 부품 중 양극산화피막법(Anodizing)으로 피막을 성장시킨 anodic aluminum oxide (AAO)부품은 플라즈마에 의해 화학적, 물리적 침식이 발생하여 코팅막과 모재에 손상을 일으키며 코팅막이 깨지거나 박리되면서 다량의 Particle이 생성됨으로써 공정상의 여러 가지 문제를 야기 시킨다고 알려져 있다. 하지만 코팅막을 평가하는 방법은 거의 전무하며 기본물성 측정방법인 피막두께, 내전압, 임피던스, 내식성 측정방법을 통하여 여러 기본물성측정방법으로 부품의 평가기술을 연구하였다. 본 연구에서는 이러한 진공 부품의 하나인 anodic aluminum oxide (AAO)부품샘플을 누설전류 및 내전압 측정하여 샘플의 전기적 특성을 측정하였고, 표면 미세구조의 변화를 관찰하였다. 부식실험으로는 HCl 가스를 발생시켜 부식정도를 알아봤으며, 부식처리와 플라즈마 처리 모두 코팅 막의 손상과 전기적 특성의 감소를 보였다. 진공장비 전극 부품평가의 유익한 평가 항목으로서 플라즈마 데미지를 주는 도중에 실시간으로 부품평가에 따른 Particle을 측정함으로써 ISPM 장비를 이용하여 진공 장비용 코팅부품이 플라즈마공정에서 발생하는 오염입자를 측정할 수 있는 방법을 연구하였다. 이러한 결과를 이용하여 진공공정에서 사용되는 코팅부품이 플라즈마에 의한 손상정도를 정량화 하고 평가방법을 개발하여 진공장비용 공정 중 실시간으로 부품의 성능평가가 가능하고 코팅부품 신뢰성 향상이 가능할 것으로 본다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.7
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• pp.448-451
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• 2014

Anodic aluminum oxides (AAO) fabricated by the two-step anodizing process have attracted much attention for the fabrication of nano template because of pore structure with high aspect ratio, low cost process and ease of fabrication. AAOs are characterized by a homogeneous morphology of parallel pores that grow perpendicular to the template surface with a narrow distribution of diameter, length and inter-pores spacing, all of which can be easily controlled by suitably choosing of the anodizing parameters such as pH of the electrolyte, anodizing voltage and duration of anodizing. In this study, AAO templates were characterized by X-ray diffraction and field-emission scanning electron microscope (FE-SEM). The dependence of the pore size change according to the amount of addition of phosphoric acid, which was used to remove the initial alumina oxide layer, was not observed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.4
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• pp.249-251
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• 2015

In this study, the application of biosensor having a large surface area for more effective and AAO (anomic aluminium oxide) template in order to gain concentration and voltage of anodizing process morphology changes to the control of experiments were conducted. The biosensor surface may increase the response characteristics by having a large surface area. So the entrance to a little more efficient wide depth sensing experiment was carried out to obtain a structure body with a branch shape with a large surface area with increasing. Experimental results from the FE-SEM observation was obtained template morphology. As a result, depending on the anodizing time, the depth of the layer of aluminum oxide was found that it was confirmed that the deepening of the pore size changes according to anodizing condition. And measuring the detection performance according to the conditions in the electrolyte and the reaction because of blood using a biosensor measuring sensing property according to the depth of the pore depth is considered that does not have a significant impact.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.10
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• pp.741-744
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• 2013

In this study, we fabricated anodic aluminum oxide (AAO) membrane by two step anodizing process for pH detection. The structural properties were observed by X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). Electrochemical measurements of the pH sensor have been performed in capacitance-voltage (C-V) and drift rates. The characterization of AAO membrane exhibited high sensitivity (99.1 mV/pH) at second anodizing time of 4 min.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.6
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• pp.394-398
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• 2014

We fabricated the electrolyte-dielectric-metal (EDM) sensor on the base of AAO (anodic aluminum oxide) template with variation of the anodizing temperature. When a surface is immersed or created in an aqueous solution, a discontinuity is formed at the interface where such physicochemical variables as electrical potential and electrolyte concentration change significantly from the aqueous phase to another phase. Because of the different chemical potentials between the two phases, charge separation often occurs at the interfacial region [1]. This interfacial region, togeter with the charged surface, is usually known as the electrical double layer (EDL) [2]. The structural and electrochemical properties of AAO sensor were investigated for applications in capacitive pH sensors. To change the thickness of the AAO template, the anodizing temperature was varied from $5^{\circ}C$ to $20^{\circ}C$, the thickness of the AAO template invreased from 300 nm to 477 nm. The pH sensitivity of sensors with the anodizing temperature of $20^{\circ}C$ showed the highest value of 56.4 mV/pH in the pH range of 3 to 11. The EDM sensor with the anodizing temperature of $20^{\circ}C$ exhibited the best long-term stability of 0.037 mV/h.