• Journal of the Korean Ceramic Society
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• v.40 no.9
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• pp.842-848
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• 2003

Semiconducting $\alpha$-Fe$_2$O$_3$ film was prepared by the cathodic electrodeposition method on Indium Tin Oxide (ITO) substrate for photoelectrochemical cell application. After heat treatment at 50$0^{\circ}C$, the phase was changed from Fe to $\alpha$-Fe$_2$O$_3$. The phase, morphology, absorbance, and photocurrent density (A/$\textrm{cm}^2$) of the film depended on the preparation conditions: deposition time, applied voltage, and the duration of heat treatment. The $\alpha$-Fe$_2$O$_3$ film was characterized by X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM), and UV -Visible Spectrophotometer. The stability of the $\alpha$-Fe$_2$O$_3$ film in aqueous solution was tested at zero bias potential under the white-light source of 100 mW/$\textrm{cm}^2$. The apparent grain size of the films formed at -2.0 V was larger than that grown at -2.5 V. The $\alpha$-Fe$_2$O$_3$ film deposited at -2.0 V for 180 s and heat-treated at 50$0^{\circ}C$ for 1 h showed the predominant photocurrent of 834$\mu$A/$\textrm{cm}^2$.

• Journal of Navigation and Port Research
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• v.39 no.4
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• pp.277-283
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• 2015

MS(Mild Steel), HTS(High Tensile Steel), HYS(High Yield Steel), AL(Aluminum Alloy) and Composite Materials are used for vessels. Steel Materials are mostly used for vessels because body of a ship have to perform the basic functions such as watertight, preserving the strength and supporting the equipments. The vessels primarily carry out a mission at ocean, so that body of a ship is necessarily rusted. There are several methods to protect the corrosion of vessels such as painting, SACP(sacrificial anode cathodic protection) and ICCP(impressed current cathodic protection). For the sacrificial anode cathodic protection, Al and Zn alloys are normally used. Heavy metals are added to the Al and Zn Alloys for improving the corrosion properties but they are so harmful to the human and environment. Therefore, the use of these heavy metals is strictly regulated in the world. In this paper, Al and Zn Alloys are made by adding the trace elements(Ma, Ca, Ce and Sn) which is not harmful to the human and environment. SEM, XRD, Potentiodynamic Polarization test and Current Efficiency test are conducted for evaluation of Al and Zn Alloys. As a result of the experiment, Al-3Zn-0.6Sn and Zn-3Sn Alloys are more efficient than other Alloys.

• Resources Recycling
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• v.14 no.6 s.68
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• pp.28-36
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• 2005

A hydrometallurgical process to leach cobalt from the waste cathodic active material, $LiCoO_{2}$, and subsequently to separate it by solvent extraction was developed. The optimum leaching conditions for high recovery of colbalt and lithium were obtained: 2.0 M sulfuric acid, 5 $vol.\%$ hydrogen peroxide, $75^{\circ}C$ leaching temperature, 30 minutes leaching time and an initial pulp density of 100 g/L. The respective leaching efficiencies for Co and Li were $93\%$ and $94.5\%$. About $85\%$ Co was extracted from the sulfuric acid leach liquor containing 44.72 g/L Co and 5.43 g/L Li, using 1.5 M Cyanex272 as an extractant at the initial pH 5.0 and in organic to aqueous phase ratio of 1.6:1 under the single stage extraction conditions. The Co in the raraffinate was completely extracted by 0.5 M Na-Cyanex272 at the inital pH 5.0, and an organic to aqueous phase ratio of 1;1. The cobalt sulfate solution of higher than $99.99\%$ purity could be recovered from waste $LiCoO_{2}$, using a series of hydrometallurgical processes: sulfuric acid leaching of waste $LiCoO_{2}$- solvent extraction of Co by Na-Cyanex 271 - scrubbing of Li by sodium carbonate solution - stripping of Co by sulfuric acid solution.

• 한국가스학회:학술대회논문집
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• 2003.10a
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• pp.183-187
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• 2003

• 한국가스학회:학술대회논문집
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• 2003.10a
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• pp.59-64
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• 2003

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.129-129
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• 2003

전기변색(electrochromism)은 전기화학적 산화, 환원 과정을 통해 가역적인 광학특성의 변화를 갖는 현상을 말하며, 이를 이용한 전기변색소자(electrochromic device)는 전력 소모가 적고 변색효율이 크다는 장점으로 인해 smart window, display, mirror 등에 응용될 수 있다. 전기변색소자는 구조상 투명 기판, 투명 전도체, 환원 착색 물질 (cathodic coloration material), 산화 착색 물질(anodic coloration material), 그리고 투명 이온 전도체로 구성된다. 일반적으로 투명 기판으로는 열적 안정성이 좋은 유리기판을 사용하여 window에 응용할 수 있는 장점이 있는 반면 다양한 형태를 갖는 소자를 제작하기에는 그 한계가 있다.

• Corrosion Science and Technology
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• v.2 no.1
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• pp.26-29
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• 2003

This study determined that the four corrosive characters of carbon steel in the marine splash zone (MSZ) in China's four sea areas. It has a range and a corrosion peak value. The rust in the MSZ plays the role of "depolarizer" in the cathodic process of corrosion. The growth law of the rust layer in MSZ has a character of "annual ring". In addition the reasons causing serious corrosion of carbon steel in the marine splash zone has been discussed in this paper.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.299-302
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• 1997

Generally the corrosion expansion of the steel due to outdoor corrosive environmental factor brings about serious problem on the durability of concrete structures. It is the purpose of this study to see whether adapted sacrificial anode method is effective or not. from the experimental results. the potential of steel in concrete in case of adapting the sacrificial anode method satisfies protection standard value (less than -850mV vs CSE).

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.92.1-92.1
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• 2017

고경도 질화막 합성과 밀착력 향상을 위한 기판 청정 기술은 밀접한 상관관계가 있다. 음극 진공 아크 증발원을 이용하여 기판 청정을 실시하였으며, 기판 전압이 증가함에 따라 기판 청정 효과가 증가하였으나, 그 역효과 또한 확인할 수 있었다. 특히 기판 전압 인가부의 전극 접촉부 위치에 따라 청정 형상이 크게 영향을 받음을 확인하였다. 기판 청정 후 고경도 질화막을 형성시켜 100N 이상의 밀착력 확인하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.35-35
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• 2018

물리적 증착법에 의해 제조되는 초고경도 박막은 나노다층과 나노복합 구조가 대표적이며, 본 연구에서는 음극 아크 증착법으로 TiAlN과 AlTiiN 층 조합을 이용하여 나노다층구조를 포함하는 다층막 시편을 제작하였다. 초격자 두께 주기 12.1 ~ 15.6 nm에서 35 ~ 55 GPa의 경도값을 가졌으며, 절삭공구 코팅분야에 적용할 예정이다.