• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.219-219
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• 2009

In this study, electrochemical impedance characteristics of anodic oxide layer formed on titanium ternary alloy surface have been investigated, Titanium oxide layers were grown on Ti-29Nb-xZr(x=3, 5, 7, 10 and 15 wt%) alloy substrates using phosphoric acid electrolytes.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1873-1875
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• 2005

The effect of zinc oxide as an inhibitor for the corrosion of steel in concrete environment was studied by weight loss measurements, potential-time behaviour and anodic polarization technique. The salient features of the investigation were: in 100% OPC extracts, the passivity of steel was readily destroyed, however extracts containing various concentration of zinc oxide, the passivity of steel was maintained even in the presence of 30,000 ppm of chloride. Alkalinity of concrete was maintained by the addition of zinc oxide. The efficiency of the inhibitor was found to increase with increasing inhibitor concentration. Addition of zinc oxide in the range 3 to 4% by weight of cement was sufficient to protect the rebars.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.140.1-140.1
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• 2007

• Proceedings of the Korean Vacuum Society Conference
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• 2006.02a
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• pp.199-199
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• 2006

• Proceedings of the Korean Vacuum Society Conference
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• 2003.08a
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• pp.177-177
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• 2003

• Proceedings of the Korea Crystallographic Association Conference
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• 2005.11a
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• pp.7-7
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• 2005

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.78-78
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• 2005

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.150.2-150.2
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• 2017

This research was conducted to investigate in detail the effect of $PO_4{^{3-}}$, $CO_3{^{2-}}$ and $F^-$ anions on the electrochemical properties of the thin air-formed oxide film-covered AZ31 Mg alloy. In this work, native air-formed oxide films on AZ31 Mg alloy samples were prepared by knife-abrading method and the changes in the electrochemical properties of the air-formed oxide film were investigated in electrolytes containing 0.01 M, 0.05 M and 0.1 M of $PO_4{^{3-}}$, $CO_3{^{2-}}$ and $F^-$ anions. It was observed that the trend of open circuit potential (OCP) transients changed only in the solution containing $PO_4{^{3-}}$ ions. The Nyquist plots obtained from electrochemical impedance spectroscopy (EIS) showed that the resistance of the new surface films formed in fluoride ion containing bath increased with the increase in concentration of fluoride ions but the resistance of surface films formed in carbonate ion containing bath decreased with the increase in concentration of carbonate ions. The potentiodynamic polarization curves illustrated that under anodic polarization, there was growth of porous passive layer only in fluoride ion containing solution while the surface layer formed in phosphate and carbonate ion containing solutions lost its passivity at high anodic potential of $2.5V_{Ag/AgCl}$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.7 s.250
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• pp.773-778
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• 2006

High-aspect-ratio nano-hair or nano-pillar arrays have great potential in a variety of applications. In this study, we present a simple and cost-effective replication method of high-aspect-ratio polymer nano-hair arrays. Highly ordered nano-porous AAO (anodic aluminum oxide) template was utilized as a reusable nano-mold insert. The AAO nano-mold insert fabricated by the two-step anodization process in this study had close- packed straight nano-pores, which enabled us to replicate densely arranged nano-hairs. The diameter, depth and pore spacing of the nano-pores in the fabricated AAO nano-mold insert were about 200nm, $1{\mu}m$ and 450nm, respectively. For the replication of polymer nano-hair arrays, a UV nano embossing process was applied as a mass production method. The UV nano embossing machine was developed by our group for the purpose of replicating nano-structures by means of non-transparent nano-mold inserts. Densely arranged high-aspect-ratio nano-hair arrays have been successfully manufactured by means of the UV nano embossing process with the AAO nano-mold insert under the optimum processing condition.

• 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.