• Corrosion Science and Technology
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• 제4권6호
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• pp.217-221
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• 2005

In the present investigation, holographic interferometry was utilized for the first time to monitor in situ the thickness of the oxide film of aluminium samples during anodization processes in boric acid solutions. The anodization process (oxidation) of the aluminium samples was carried out by the technique of the electrochemical impedance spectroscopy(EIS), in different concentrations of boric acid (0.5-5.0% $H_3BO_3$) at room temperature. In the mean time, the real-time holographic interferometry was used to measure the thickness of anodized (oxide) film of the aluminium samples in solutions. Consequently, holographic interferometry is found very useful for surface finish industries especially for monitoring the early stage of anodization processes of metals, in which the thickness of the anodized film of the aluminium samples can be determined without any physical contact. In addition, measurements of electrochemical values such as the alternating current (A.C) impedance(Z), the double layer capacitance($C_{dl}$), and the polarization resistance(Rp) of anodized films of aluminium samples in boric acid solutions were made by the electrochemical impedance spectroscopy(EIS). Attempts to measure electrochemical values of Z, Cdl, and Rp were not possible by holographic interferometry in boric acid especially in low concentrations of the acid. This is because of the high rate of evolutions of interferometric fringes during the anodization process of the aluminium samples in boric acid, which made measurements of Z, Cdl, and Rp are difficult.

• 한국표면공학회지
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• 제35권3호
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• pp.149-157
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• 2002

Spectral emissivity depends on the surface conditions of the materials. The mechanisms that affect the spectral emissivity in anodic oxide films on aluminum were investigated. The aluminum specimens were anodized in a sulfuric acid solution and the thickness of the resulting oxide film formed changed with the anodizing time. FT-IR spectrum analysis identified the anodic oxide film as boehmite ($Al_2$$O_3$.$H_2$O). Both the infrared emisivity and reflectivity of the anodized aluminum were affected by the structure of the anodic oxide film because Al-OH and Al-O-Al have a pronounced absorption band in the infrared region of the spectrum. The presence of an anodic oxide film on aluminum caused a rapid drop in the infrared reflectivity. An aluminum surface in the clean state had an emissivity of approximately 0.2. However, the infrared emissivity rapidly increased to 0.91 as the thickness of the anodic oxide film increased.

• 한국표면공학회지
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• 제45권5호
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• pp.198-205
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• 2012

The corrosion properties of anodized films on aluminium 6070 alloy in a sulfuric acid have been studied. Comparison to evaluate the anodized A6070 and pure 6070 specimen, corrosion tests in $HNO_3$ vapor environment of the 20 wt.% were performed up to 72 hours. Characteristics of film formation and surface morphology were examined by optical microscopy, FE-SEM, and EDS. The oxide film anodized in the sulfuric acid solution contained 5 to 10 wt.% of sulfur. In the initial stages of corrosion, anodized specimens exhibited corrosion resistance than the pure specimen. However, the corrosion conditions in 24 hours, corrosion was far more anodized specimen than pure specimen. Therefore, anodized films contained sulfur, nitric acid vapor in the environment is thought to stimulate corrosion.

• 대한전기학회논문지
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• 제31권9호
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• pp.74-81
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• 1982

One of the stable thin film transistor fabricated by cadmium suifide with the anodized aluminium oxide as gate material. The principle of the operation for the device is based on the control mechanism of injected majority carricrs to the wide band gap semiconductor, that is cadmium sulfide, by means of the function of the gate control. The fabricated device constructed by evaporating CdS layer in the form of microcrystalline on the oxided thin film characterized by ea, 80 as voltage amplification factor, 1/100 mho as transconductance, 8 kohm as dynamic output resistance, furthermore gain band width products is about 15 MHz.

• 한국표면공학회지
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• 제49권4호
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• pp.357-362
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• 2016

In this study, we manufactured the anodized alumina oxide (AAO) template and fabricated the carbon nanofibers and manganese oxide nanofibers using AAO template for application to electrochemical capacitor. Pore diameters of the AAO template were increased from 50 to 90 nm by increasing the acid treatment time after two-step anodizing process. Furthermore nanofibers, which is fabricated by AAO template, showed uniform diameter and micro structure. It is suggested that the surface area is larger than commercial electrode material and it is enhancing the energy density by increasing the specific capacitance.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.372.2-372.2
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• 2016

Various nanobiosensors have been developed and extensively investigated. For their practical applications, however, the reproducibility and uniformity should be good enough and the mass-production should be possible. To fabricate anodized aluminium oxide (AAO)-based nanobiosesnor on wafer scale, we have designed and constructed a wafer-scale anodizing system. $1{\mu}m$-thick-aluminum is deposited on 4 inch SiO2/Si substrate and then anodized, resulting in uniform nanopores with an average pore diameter of about 65 nm. Furthermore, most AAO sensors constructed on this wafer provide capacitance values of 30 nF ~ 60 nF in PBS, demonstrating their uniformity.

• Corrosion Science and Technology
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• 제15권4호
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• pp.166-170
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• 2016

The combined process of porous type anodizing and desiccation treatment was applied to improve wettability of A1050 aluminum alloy. The water contact angles of anodized samples were increaseds considerably with desiccation treatment. However, there was no considerable effect of polishing and anodizing time on water contact angle. The corrosion behavior with the treatments was investigated electrochemically. The corrosion resistance of the samples in 3.5 mass% NaCl solutions increased with higher contact angle. Anodized and desiccated samples showed better corrosion resistance than un-desiccated samples around rest potential region.

• 한국표면공학회지
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• 제33권5호
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• pp.309-318
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• 2000

The 6063 Aluminium alloy were electrocolored and anodized at the same time in addition of $CoSO_4$, $FeSO_4$, in the electrolyte and investigated by AES/SAM. It was found that the thickness of anodic oxide film is increased linearly in DC type, and DC combined AC type, the more ratio of anodic Portion in AC, the more increased of anodic film thickness. The color of anodic film was changed from silver to yellow when the increase of the ratio of cathodic portion in AC. Also the increase of $CoSO_4$, $FeSO_4$ in the electrolyte, the coloring time is decreased. From the AES/SAM results, the element of anodic oxide film are Al,O and S. The result of depth profile, the most of the S distributed on the surface and the more S is in DC combined AC type than only DC type.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.315-316
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• 2006

We fabricated GaN nanopores m the etching process of anodic oxidation of aluminum. The aluminum was deposited by using E-beam evaporator on p-type GaN. After the aluminum was anodized GaN structure was exposed to the electric field with the oxidat species. The fabricated nanopore structure provides the enhanced intensity of light emission at the wavelengths 470 nm. We investigated the structure of the GaN nanopores from FE-SEM and EDS measurements.

• 한국재료학회지
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• 제10권5호
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• pp.375-381
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• 2000

전해콘텐서용 알루미늄박을 ammonium adipate 용액을 이용하여 $65^{\circ}C$에서 10분간 100V 및 140V로 각각 양극 산화시켜 산화 알루미늄 유전체를 만들었다. 유전층의 두께, 화학양론적 관계, 결정구조 등을 RBS 및 TEM을 이용하여 분석하였고, 알루미늄박의 에칭시 황산 첨가로 인한 표면적의 변화는 임피던스 분석법으로 조사 하였다. 생성된 유전피막은 100V 및 140V의 전압을 사용했을 경우 각각 약 130nm 및 190nm 두께의 비정질로 나타났으며 피막의 알루미늄과 산소원소의 화학양자론적 비는 약 2:3의 비율로 존재했다. 또한 유전피막은 전자빔은 조사에 의해 쉽게 $${\gamma}$-Al_2$$O_3$ 형태의 결정질로 변태 되었다. 염산 에칭욕에 황산 첨가시 나타나는 알루미늄박의 표면변화는 임피던스 분석결과와 정전 용략의 변화가 일치하는 경향을 나타냈다.