• 구강회복응용과학지
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• 제24권4호
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• pp.361-369
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• 2008

본 연구의 목적은 다공성의 티타늄 산화막에 불소를 처리한 결과를 평가하는 것이다. 디스크에 양극산화법을 통하여 다공성의 티타늄산화막표면을 얻은 후 불소를 처리하고 일정시간동안 Hank액에 침전을 시켰다. 양극산화를 통해 일정거칠기의 표면을 얻었으며 SEM과 XRD를 통하여 표면의 형상과 성분을 분석하였다. 생성된 표면은 빠른 표면 활성도를 보였으며, 적절한 거칠기와 좋은 골반응으로 골유착에 기여할 수 있을 것으로 여겨진다.

• 한국전기전자재료학회논문지
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• 제19권2호
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• pp.189-194
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• 2006

Ordered nanostructure materials have received attention due to their unique physical properties and potential applications in electronics, mechanics and optical devices. To actualize most of the proposed applications, it is quite important to obtain highly ordered nanostructure arrays. The well-aligned nanostructure can be achieved by synthesizing nanostructure material in the highly ordered template. To get well-aligned pore array and reduce process time, rapid thermal anneal by an IR lamp was employed in vacuum state at $500^{\circ}C$ for 2 hour. The pore array is comparable to a template annealed in vacuum furnace at $500^{\circ}C$ for 30 hours. The well-fabricated AAO template has the mean pore diameter of 70 nm, the barrier layer thickness of 25 nm, the pore depth of $9{\mu}m$, and the pore density of higher than $1.2{\times}10^{10}cm^{-2}$.

• 한국재료학회지
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• 제12권2호
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• pp.121-128
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• 2002

Anodic alumina layer can be used as templates for preparation of nano-structured materials, because porous oxide layer on aluminum shows a uniform pore size and a high pore density. In order to find out possibility for template material to prepare nano wire, the effects of the anodic applied potential, anodic time and the temperature of electrolyte on pore diameter of anodic alumina layer were studied using SEM and AFM. The pore diameter of anodic alumina layer increased with applied anodic potential and electrolytic temperature. Especially, the pore diameter of anodic oxide layers formed in chromic acid can be well replicated by widening process in $H_3$$PO_4$solution.

• 한국치위생학회지
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• 제7권4호
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• pp.471-479
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• 2007

The purpose of this study was to examine the optimum condition of impulse during the anodic spark oxidation applying pulse current as well as to find the excellent condition for HA precipitation the after electrochemical hydrothermal treatment by cathode reduction method. After anodic spark oxidation, the anodized specimen and the Pt plate connected cathode and anode, respectively. Hydrothermal treatment performed at 90, 120, $150^{\circ}C$ for 2 hours in the electrolyte containing $K_2HPO_4$, $CaCl_2{\cdot}2H_2O$, Tris(Hydroxymethyl)-$(CH_2OH)_3\;CNH_2$(Aminomethane), and NaCl. The optimum impulse voltage for anodic spark oxidation was 350V. The optimum pulse cycle measured at 10 mS. The HA crystals precipitated excellently by cathode reduction at $150^{\circ}C$ for 2 hours. The phases of anatase, rutile, and HA coating on the surface of modified titanium surface immersed in Hanks' solution for 3weeks were detected by XRD measurement and the intensity of HA crystal phase has increased by temperature and time of hydrothermal treatment. According to the our experiments, we found that Pure Ti will be good materials of bioactivity and biocompatibility.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2012년도 추계총회 및 학술대회 논문집
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• pp.17-17
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• 2012

Magnesium alloys exhibit many attractive properties such as low density, high strength/weight ratio, high thermal conductivity, very good electromagnetic features and good recyclability. However, most commercial magnesium alloys require protective coatings because of their poor corrosion resistance. Attempts have been made to improve the corrosion resistance of the Mg alloys by surface treatments, such as chemical conversion coatings, anodizing, plating and metal coatings, are commonly applied to magnesium alloys in order to increase the corrosion resistance. Among them, chemical conversion coatings are regarded as one of the most effective and cheapest ways to prevent corrosion resistance. In this study, zinc phosphate conversion coatings on various Mg alloys have been developed by selecting proper phosphating bath composition and concentration and by optimizing phosphating time, temperature. Morphology, coatings composition, corrosion resistance, adhesion and its formation and growth mechanism of the zinc phosphate conversion coatings were studied. Results have shown some attractive properties such as simplicity in operation, significantly increased corrosion protective property. However, adhesions between coatings and substrate and also between coatings and paint are still not satisfied. Resolving the problems and understanding the mechanism of phosphating process are targets of our study.

• Corrosion Science and Technology
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• 제7권3호
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• pp.168-172
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• 2008

A new type of electrochemical random signal (electrochemical noise) analysis technique was applied to localized corrosion of anodic oxide film formed 1100 aluminum alloy in $0.5kmol/m^3$ $H_3BO_4/0.05kmol/m^3$ $Na_2B_4O_7$ with $0.01kmol/m^3$ NaCl. The effect of anodic oxide film structure, barrier type, porous type, and composite type on galvanic corrosion resistance was also examined. Before localized corrosion started, incubation period for pitting corrosion, both current and potential slightly change as initial value with time. The incubation period of porous type anodic oxide specimens are longer than that of barrier type anodic oxide specimens. While pitting corrosion, the current and potential were changed with fluctuations and the potential and the current fluctuations show a good correlation. The records of the current and potential were processed by calculating the power spectrum density (PSD) by the Fast Fourier Transform (FFT) method. The potential and current PSD decrease with increasing frequency, and the slopes are steeper than or equal to minus one (-1). This technique allows observation of electrochemical impedance changes during localized corrosion.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.162-165
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• 2007

AAO(Anodic Aluminum Oxidation) method has been known that it is practically useful for the fabrication of nano-structures and makes it possible to fabricate the highly ordered nano masters on large surface and even on the 2.5 or 3D surface at low cost comparing to the expensive e-beam lithography or the conventional silicon processing. In this study, by using the multi-step anodizing and etching processes, highly ordered nano patterned master with concave shapes was fabricated. By varying the processing parameters, such as initial matter and chemical conditions; electrical and thermal conditions; time scheduling; and so on, the size and the pitch of the nano pattern can be controlled. Consequently, various alumina/aluminum nano structures can be easily available in any size and shape by optimized anodic oxidation in various aqueous acids. In order to replicate nano patterned master, the resulting good filled uniform nano molded structure through electro-forming process shows the validity of the fabricated nano pattern masters.

• 한국재료학회지
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• 제14권2호
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• pp.133-140
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• 2004

We carried out anodic aluminum oxide (AAO) on a Si and a sapphire substrate. For anodic oxidation of Al two types of specimens prepared were Al(0.5 $\mu\textrm{m}$)!Si and Al(0.5 $\mu\textrm{m}$)/Ti(0.1 $\mu\textrm{m}$)$SiO_2$(0.1 $\mu\textrm{m}$)/GaN(2 $\mu\textrm{m}$)/Sapphire. Surface morphology of Al film was analyzed depending on the deposition methods such as sputtering, thermal evaporation, and electron beam evaporation. Without conventional electron lithography, we obtained ordered nano-pattern of porous alumina by in- situ process. Electropolishing of Al layer was carried out to improve the surface morphology and evaluated. Two step anodizing was adopted for ordered regular array of AAO formation. The applied electric voltage was 40 V and oxalic acid was used as an electrolyte. The reference electrode was graphite. Through the optimization of process parameters such as electrolyte concentration, temperature, and process time, a regular array of AAO was formed on Si and sapphire substrate. In case of Si substrate the diameter of pore and distance between pores was 50 and 100 nm, respectively. In case of sapphire substrate, the diameter of pore and distance between pores was 40 and 80 nm, respectively

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.328-328
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• 2007

$SnO_2$ has a high potential for electric and electronic applications. We have anodized pure tin metal and nano porous tin oxide film was obtained on pure Sn. Nano porous tin oxide were grown by anodization in nonaqueous-base electrolytes at different potentials between 5 V and 100 V. Pore size of ~100nm was observed by FE-SEM. Pore sizes as a function of applied voltage and anodizing time were characterized. We obtained nano porous tin oxide film having an uniform pore size at low temperature. High specific surface area of $SnO_2$ will be very useful for gas sensor, lithium battery, and dye sensitized solar cell.

• 한국정밀공학회지
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• 제33권12호
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• pp.993-998
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• 2016

In today's manufacturing industries, the demand for light non-ferrous materials is considerable due to the need to improve productivity and manufacturability. Since the surface roughness of a material is important for improving the functionality of machined parts, various techniques for surface treatments have been developed to obtain non-ferrous materials with low roughness. A superfinishing method utilizing polishing films is generally applied to the anodized surface of Al7075 in order to improve its roughness. The objective of this research is to determine through experiment the parameters that facilitate the shortest processing time, using a superfinishing method, for reaching a roughness of Ra $0.2{\mu}m$. This objective is met by applying the Taguchi method in the experiments. Through the experiments of superfinishing, the effectiveness of the parameters adopted for the surface treatment is demonstrated.