• Journal of the Korean Society for Heat Treatment
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• v.2 no.2
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• pp.68-83
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• 1989

Physical metallurgy aspects of gaseous ferritic nitrocarburising are reviewed in the light of basic studies undertaken since 1975 which have illustrated inconsistencies between the iron-carbon-nitrogen ternary phase diagram at $570^{\circ}C$ and the experimental observation of the co-existence of the ${\varepsilon}$ carbonitride phase and ferrite. Thermodynamic investigations by Xu and Li together with those by Slycke et al are reviewed to illustrate compatability between a modified isothermal section of the Fe-C-N system and the formation and growth of a monophased ${\varepsilon}$ structure under a variety of processing conditions. The implications of the modified diagram in terms of innovations in industrial ferritic nitrocarburising practice are discussed, together with limitations on the control of the process. The importance of the developing technology of black nitrocarburising for enhanced wear, fatigue, and corrosion resistance is emphasised. Basic studies and industrial status of austenitic nitrocarburising treatments are also reviewed, which highlight the importance of substrate strengthening for high load bearing applications of anti-scuff thermochemical treatments.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.129-129
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• 2014

본 연구는 알루미늄 및 구리 캐리어 소재상에 화학 동도금(Chemical Copper)으로 형성된 극박 동박 표면 및 석출막의 특성 평가에 관한 연구이다. 평가에 사용된 극박 동박은 현재 캐리어박 선점률이 높은 M, J, Y사의 제품이다. 최상층 구리 표면에서 조직, 조성, 표면조도를 평가하였고, 단면 평가에서는 copper layer 및 nodule layer, adhesion layer, anti-corrosion layer, release layer, substrate에서의 물성 및 특성을 평가하였다.

• Proceedings of the KWS Conference
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• 1994.05a
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• pp.222-225
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• 1994

The weldability of aluminum is excel lent but weld metal is subject to include weld defects such as porosities, crack, incomplete penetration and incomplete fusion because of improper welding parameters. Especially, the porosities are main weld defects because the difference of hydrogen solubility change in melt ins and solidification state with temperature changing. Deformation of aluminum is larger than mi Id steel due to higher thermal conductivity. It is reported that porosities in deposited metal affect tensile strength and elongation. Therefore, the effect of groove angle on porosities and mechanical properties of weld metal were researched in this report where Al-5083 plate was used with 5356 filler metal that are excellent anti corrosion and strength.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.2
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• pp.191-197
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• 2001

In this study, the admixtures for agents for enduring cold weather used widely are collected and applied to cement mortar to analyze the strength development due to variation of curing temperature at early age. The test results show that anti-freezing admixture have some problems due to high chloride content, which may cause the corrosion of reinforcement embedded in concrete. However, the mortar applied by accelerator and another kind of agent for enduring cold weather produced by S company lead to delay of strength development in low temperature. Also, it is clarified that there are no significant problems for cement mortar in strength development due to low temperature if a suitable kind of agent enduring cold weather is used and cement mortar is cured for more than $7.5^{\circ}D.D$ at early age.

• Journal of the Korean Society of Safety
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• v.16 no.2
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• pp.91-96
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• 2001

Theoretical definitions of mixed behavior of PE panel and connote should have preceded to cause a mixed behavior of connote and polyethylene which have different elastic module, one-line expansion coefficients, poison ratios, compressive strengths and tensile strengths. Consequently, changes are analyzed through experiment process to identify the effects on interpretation of mixed behavior on the basis of temperature change of structures, temperature rise of concrete other than PE panel due to hydration heat temperature rise of concrete other than PE panel due to drying and contraction, working of hydrostatic pressure by storage and temperature gradient From the results of interpretation of the analysis, it is concluded that PE panel have slight influences on the change of guess of structures and maintains structural stability compared with concrete structures without PE panel.

• Journal of Korea Technology Innovation Society
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• v.7 no.1
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• pp.159-181
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• 2004

본 연구에서는 신차개발 과정에서 공급업체의 조기참여 프로그램을 통한 자동차용 강판 제조업체의 기술혁신에 대해 고려하기로 한다. 먼저, 치열한 경쟁 하에 놓인 자동차용 강판 공급업체의 생존전략으로 자동차업체와의 기술적 파트너십의 중요성과 함께 시장을 둘러싼 대내외 경영환경을 분석하고자 한다. 자동차산업의 신차개발 프로세스 단계별 기술적 목표를 명확히 제시하고 차체의 수명사이클에 근거한 최적 소재를 선정하기 위한 조기참여 활동의 필요성을 강조하고자 한다. 또한 자동차용 강판 공급업체의 최적 기술전략 수립 및 방향을 설정하기 위해 자동차용 소재시장에서의 철강재 위상을 제고하고, 핵심 기술목표를 도출하고자 한다. 마지막으로 자동차용 강판 제조업체의 핵심 기술로 고성형성, 고강도강판 및 내식성이 우수한 도금강판에 대해 공급업체의 조기 참여를 통한 기술혁신 과정을 살펴보고자 한다.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.4
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• pp.49-55
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• 2011

Recently, various efforts to make more speedy and precision machine tool to improve productivity and also various efforts to solve environmental problem are going on, so that dry cutting in manufacturing industry, which needs environmental conscious design and development of manufacturing technique, is becoming a very important assignment to solve. Because dry cutting does not use cutting fluid, we need other methods that can be used instead of cutting fluid, which does cooling, lubricating, chip washing, and anti-corrosion. Especially, because turning is a continuous work, the consideration of tool life and surface roughness due to continuous heat and poor lubrication is important. The purposes of this paper are the consideration of how well the compressed air can work instead of cutting fluid, and also the development of the method to select the optimum machining condition by the minimum numbers of experiments through the Taguchi method.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.145-151
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• 2016

In response to the cavitation caused by the partial vacuum caused by the fluid flow, a paint was developed by dispersing the lamella-shaped glass-flake in resin for anti-cavitation. This composite paint was developed by using the inorganic filler (lamella shaped glass-flake) and the NBR (Acrylonitrile-butadiene rubber) which was modified epoxy resin. Especially, the glass-flake was a thin film with a thickness of about 100~200 nm and length of about $20{\sim}30{\mu}m$, the aspect ratio was about 200 to 300 times that of the plate-shaped. So the paint for anti-cavitation have shown excellent performance in corrosion resistance. The results of evaluating anti-cavitation performance was below, tensile strength $4.8{\sim}6N/mm^2$ or more, rupture elongation 30% or higher, abrasive speed $10mm^2/h$ or less. In particular, it showed more than twice the superior performance compared to existing advanced foreign products in anti-cavitation performance evaluation.

• Special Issue of the Society of Naval Architects of Korea
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• 2006.09a
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• pp.46-52
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• 2006

For ships, heat resistant coating is applied on the aluminized steel pipe systems dealing with high temperature steam over $200^{\circ}C$. The coatings on these steam pipes should retain both heat resistance and anti-corrosion properties to provide long-term resistance against coating defects (rust, delamination and crack) under the harsh outdoor environment including repeated seawater wetting and condensation. Thus, it is important to improve the coating qualities and to reduce maintenance works for these steam pipe systems. In this study, five different commercial heat resistant coatings (A, B, C, D, E) were selected for evaluation. Various physical properties of these coatings were evaluated on the coatings applied on the aluminized steam pipes. FT-IR analysis was also employed to identify the factors contributing the degree of heat resistance and durability of each coating material. The results indicated that the heat resistance capacity of coatings increased with the increase of silicon content as well as the decrease of substituent content. Both products C and D showed the best coating qualifies, which can be standard coating systems for future steam pipe areas.

• Journal of the Korean institute of surface engineering
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• v.45 no.6
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• pp.232-241
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• 2012

Cr-Ti-B-N coatings were synthesized by a hybrid coating system combining high power impulse magnetron sputtering (HIPIMS) and DC pulse magnetron sputtering from a $TiB_2$ and a Cr target in argon-nitrogen environment, respectively. By changing the power applied on the Cr and $TiB_2$ cathodes, the Cr-Ti-B-N coatings with various Ti/Cr ratio and B content were deposited. The phase structure, microstructure and chemical compositions of the Cr-Ti-B-N coatings were studied by X-ray diffraction (XRD), transmission scanning electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). With increase of Cr element in the coatings, the nanocomposite microstructure consisting of nano-sized (Cr, Ti) N crystallites and amorphous BN phase were obtained in the coatings. The microhardness of the Cr-Ti-B-N coatings exhibited a peak value of ~41 GPa for the $CrTi_{0.1}B_{0.4}N_{1.3}$, and then decreased with further increase of Cr content in the coatings, and all the coatings exhibited low friction coefficient. The oxidation and corrosion behavior of the Cr-Ti-B-N coatings revealed better properties due to the formation of a nanocomposite microstructure.