• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.125-125
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• 2015

Ti-Al-Cr-N thin layer was prepared on Fe-Si thin sheet by arc ion plating to improve corrosion and mechanical properties. The compositions ratios of Fe : Cr : Al : Ti : Si : N of the thin layers at $500^{\circ}C$ was 1.24 : 0.56 : 36.82 : 32.72 : 0.59 : 28.07 [wt.%], respectively. The higher arc ion plating temperature was, the higher corrosion resistance and nano-hardness were observed due to chromium content. Corrosion potential and corrosion rate in artificial sea water of the coating layer were in the range of $-39mV_{SHE}$ and $2mA/cm^2$, respectively. Passivity was not observed in the artificial sea water. Nano-hardnesses of the thin layers was increased by adding Cr from 23.6 to 25.8 [GPa]. The friction coefficients and fatigue limits of the layers were 0.388, 0.031, respectively.

• Journal of the Korean institute of surface engineering
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• v.52 no.6
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• pp.310-315
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• 2019

The use of a silicon carbide (SiC)-based composite ceramic layer for the mold of a curved cover glass was demonstrated. The stress of SiC/VDR/graphite-based mold structure was evaluated via finite element analysis. The results revealed that the maximum tensile stress primarly occured at the edge region. Moreover, the stress can be reduced by employing a relatively thick SiC coating layer and, therefore, layers of various thicknesses were deposited by means of chemical vapor deposition. During growth of the layer, the orientation of the facets comprising the SiC grain became dominant with additional intense SiC(220) and SiC(004). However, the roughness of the SiC layer increased with increasing thickness of the layer and. Hence, the thickness of the SiC layer needs to be adjusted by values lower than the tolerance band of the curved cover glass mold.

• Journal of Ocean Engineering and Technology
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• v.25 no.6
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• pp.60-65
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• 2011

A low temperature plasma carburizing process was performed on AISI 316L austenitic stainless steel to achieve an enhancement of the surface hardness without degradation of its corrosion resistance. Attempts were made to investigate the influence of the processing temperatures on the surface hardened layer during low temperature plasma carburizing in order to obtain the optimum processing conditions. The expanded austenite (${\gamma}_c$) phase, which contains a high saturation of carbon (S phase), was formed on all of the treated surfaces. Precipitates of chromium carbides were detected in the hardened layer (C-enriched layer) only for the specimen treated at $550^{\circ}C$. The hardened layer thickness of ${\gamma}_c$ increased up to about $65{\mu}m$ with increasing treatment temperature. The surface hardness reached about 900 $HK_{0.05}$, which is about 4 times higher than that of the untreated sample (250 $HK_{0.05}$). A minor loss in corrosion resistance was observed for the specimens treated at temperatures of $300^{\circ}C{\sim}450^{\circ}C$ compared with untreated austenitic stainless steel. In particular, the precipitation of chromium carbides at $550^{\circ}C$ led to a significant decrease in the corrosion resistance. A diamond-like carbon (DLC) film coating was applied to improve the wear and friction properties of the S phase layer. The DLC film showed a low and stable friction coefficient value of about 0.1 compared with that of the carburized surface (about 0.45). The hardness and corrosion resistance of the S phase layer were further improved by the application of such a DLC film.

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.187-188
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• 2007

Four kinds of mirror substrates with same surface roughness were fabricated. On those substrates, a dielectric multi-layer coating with high reflectivity was deposited by ion beam sputtering technique. Most of the fused silica mirrors showed lower scattering than the ZERODUR mirrors one, which deposited on substrates similar in surface roughness. The ZERODUR mirrors scattering strongly depend on the micro-structure of $Ta_2O_5/SiO_2$ thin films wear deposited on ZERODUR substrates.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.255-255
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• 2015

나노압침방법을 적용하여 arc ion plating을 통해 제조된 TiAlSiN 코팅층의 질소 함량에 따른 나노 기계적 특성을 평가하였다. 코팅층의 질소 함량은 28~30 [at.%] 이었다. 코팅층에는 AlN, TiSi, $Al_5Ti_3$, $Ti_3AlN$, $Al_5Ti_2$ 상이 형성되었다. 질소 함량이 더 작은 코팅층의 나노경도, 마찰계수, 피로한계의 값이 높아짐을 알 수 있었다.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.985-986
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• 2006

Principal peculiarities of technology for applying coatings of metallic powders on internal surfaces of hollow cylindrical parts by centrifugal method with induction heating from internal surface of part are examined. It is shown that most effective checking and regulating method of sintered powder layer is monitoring the high-frequency current generator power upon contactless pickup indications of external surface temperature of rotating part.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2001.11a
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• pp.57-59
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• 2001

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.307-307
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• 2012

마그네슘합금은 넓은 분야에서 사용되고 있지만 높은 산화성과 화학반응성 때문에 표면처리를 하지 않고서는 사용 할 수 없다. 따라서 본 과제에서는 개발 중인 신 마그네슘 합금소재의 부식 및 피막특성을 관찰하기 위해 염수분무시험, 염수침지, 분극 시험 및 도장밀착성 내식성 시험을 시행하였다. 이 결과는 새로 개발되는 신 마그네슘 합금 성분 및 함량 결정의 기초 데이터가 될 것이다.

• Journal of the Korean Ceramic Society
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• v.35 no.7
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• pp.653-658
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• 1998

Zirconia coated NiO powders were prepared by the thermal hydrolysis of $Zro(NO_3)_2$.$6H_2O$ in a mixed solvent of alcohol and water. Amorphous zirconium hydroxide was uniformly coated on the surface of NiO powder with the thickness of 20nm. The $ZrO_2$ coating layer was crystallized to tetragonal $ZrO_2$ with the size of 40-60nm at $900^{\circ}C$. The coated NiO powder containing 15 vol% $ZrO_2$ was found to have a similar isoelectric point to that of the $ZrO_2$ The grain growth inhibition effect of the coated powders was superior to the mechanically mixed powders.

• Journal of the Korean Ceramic Society
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• v.45 no.10
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• pp.600-604
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• 2008

Although titanium-ceramic systems have gained substantial interests in dental prosthetic field, bonding problem between porcelain and titanium has not been solved. Main obstacle in titanium-porcelain bonding is excessive oxidation of titanium during porcelain firing. The effects of several coating materials on the bonding strength of titanium-porcelain system were investigated in this study. RF sputtering and electroplating of platinum significantly increased the bonding strength of porcelain-titanium specimen. However, coatings of Ni-Au, Ir, and ceramics(zirconia and hydroxyapatite) did not showed a significant effect on bonding strength. Platinum might be a promising material for the protective layer of excessive oxidation of titanium during porcelain firing, resulting in increase in the bonding strength.