• 대한기계학회논문집B
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• 제39권5호
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• pp.463-469
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• 2015

산화그래핀 소재를 합성하여 투명한 박막 코팅기술을 개발하고 특성을 평가하였다. 스핀과 스프레이 공정을 동시에 이용하여 산화그래핀을 유리 기판에 균일하게 박막코팅을 하였다. 균일하게 산화그래핀을 스핀-스프레이 공정을 이용하여 박막코팅을 하기 위하여 유리기판을 amine-functional group으로 표면개질을 하였다. 또한, 스핀-스프레이 공정을 이용하여 산화그래핀 박막을 4층까지 적층을 하였고 86% 이상의 투명도를 확보하였다. 이와 같은 합성된 산화그래핀 박막소재의 스핀-스프레이 코팅 기술은 다양한 전자제품들의 display를 대면적으로 코팅할 수 있을 것으로 기대되어진다.

• 한국분말재료학회지
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• 제29권3호
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• pp.240-246
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• 2022

Novel Ni- and Fe-based alloys are developed to impart improved mechanical properties and corrosion resistance. The designed alloys are manufactured as a powder and deposited on a steel substrate using a high-velocity oxygen-fuel process. The coating layer demonstrates good corrosion resistance, and the thus-formed passive film is beneficial because of the Cr contained in the alloy system. Furthermore, during low-temperature heat treatment, factors that deteriorate the properties and which may arise during high-temperature heat treatment, are avoided. For the heattreated coating layers, the hardness increases by up to 32% and the corrosion resistance improves. The influence of the heat treatment is investigated through various methods and is considered to enhance the mechanical properties and corrosion resistance of the coating layer.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.699-700
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.391-392
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• 2009

• 한국표면공학회지
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• 제40권3호
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• pp.138-143
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• 2007

The effects of texturing and anti-reflection coating on the reflection properties of multi-crystalline silicon solar cell have been investigated. The chemical solutions of alkaline and acidic etching solutions were used for texturing at the surface of multi-crystalline Si wafer. Experiments were performed with various temperature and time conditions in order to determine the optimized etching condition. Alkaline etching solution was found inadequate to the texturing of multi-crystalline Si due to its high reflectance of about 25%. The reflectance of Si wafer texturing with acidic etching solution showed a very low reflectance about 10%, which was attributed to the formation of homogeneous. Also, deposition of ITO anti-reflection coating reduced the reflectance of multi-crystalline si etched with acidic solution($HF+HNO_3$) to 2.6%.

• 한국농공학회논문집
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• 제46권4호
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• pp.39-46
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• 2004

This experiment was carried out to study on the effect of surface coating on thermal insulation of farm structures to improve thermal resistance and reflective effect of solar radiation. Nine different types of experimental specimen were compared in the temperature variations of inside and outside; A, B, C, D. E and F types are box container and G, H and I types are drum container. The size of these containers is $1,500{\times}2,000{\times}2,500$ mm and ${\varphi}$ $280{\times}330$ mm, respectively. Specimen of 3-type box(A, B, C) is galvanized steel sheet of thickness 0.45 mm. D, E and F types are sandwich panel of the thickness 50 mm inserted with urethane, glass wool and polystyrene form, respectively. G, H and I types are paint pot using in general. The surface of A. D, E, F and I types didn't any treatment, B, C and G types were treated with thermal insulation coating on the outside surface(B, G) or the inside and outside surface(C). And H type was treated with water paint coating on the only outside surface. In general, the experimental results showed the following tendencies; In case of A, B and C types. it was found that the thermal insulation effect of types coated with thermal insulation coating was improved remarkably than that of no treatment. And the thermal insulation effect between steel sheet and sandwich panel type was nearly similar There was not a significant difference of thermal insulation effect between thermal insulation coating and water paint coating. In time of drum container filled with rough rice, The difference of heat transfer tendency and temperature variation among surface treatments was nearly similar that of box types of galvanized steel sheet. And there was time lag about 6 hours between the temperature of middle part of rice and that of inside or outside surface.

• 한국재료학회지
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• 제23권1호
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• pp.72-80
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• 2013

Recently, consumption of magnesium alloys has increased especially in the 3C (computer, communication, camera) and automobile industries. The structural application of magnesium alloys has many advantages due to their low densities, high specific strength, excellent damping and anti-eletromagnetic properties, and easy recycling. However, practical application of these alloys has been limited to narrow uses of mild condition, because they are inferior in corrosion resistance and wear resistance due to their high chemical reactivity and low hardness. Various wet and dry processes are being used or are under development to enhance alloy surface properties. Various conversion coating and anodizing methods have been developed in a view of eco-friendly concept. The conventional technologies, such as diffusion coating, sol-gel coating, hydrothermal treatment, and organic coating, are expected to be newly applicable to magnesium alloys. Surface treatments for metallic luster or coloring are suggested using the control of the micro roughness. This report reviews the recent R&D trends and achievements in surface treatment technologies for magnesium alloys.

• Archives of Metallurgy and Materials
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• 제64권2호
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• pp.547-550
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• 2019

Porous metals show not only extremely low density, but also excellent physical, mechanical and acoustic properties. In this study, Hastelloy powders prepared by gas atomization are used to manufacture 3D geometries of Hastelloy porous metal with above 90% porosity using electrostatic powder coating process. In order to control pore size and porosity, foam is sintered at 1200~1300℃ and different powder coating amount. The pore properties are evaluated using SEM and Archimedes method. As powder coating amount and sintering temperature increased, porosity is decreased from 96.4 to 94.4%. And foam density is increased from 0.323 to 0.497 g/cm³ and pore size is decreased from 98 to 560 ㎛. When the sintering temperature is increased, foam thickness and strut thickness are decreased from 9.85 to 8.13mm and from 366 to 292 ㎛.

• 대한치과보철학회지
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• 제45권5호
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• pp.675-686
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• 2007

Statement of problem: Titanium nitride(TiN) coatings are the most general and popular coating method and used to improve the properties of metallic surface for industrial purposes. When TiN coating applied to the abutment screw, frictional resistance would be reduced, as a results, the greater preload and prevention of the screw loosening could be expected. Purpose: The purpose of this study was to investigate mechanical properties of TiN coated film of various coating thickness on the titanium alloy surface and to evaluate proper coating thickness. Material and method: 95 Titanium alloy (Ti-6Al-4V) discs of 15 mm in diameter and 3 mm in thickness were prepared for TiN coating and divided into 7 groups in this study. Acceding to coating deposition time (CDT) with TiN by using Arc ion plating, were divided into 7 groups : Group A (CDT 30min), Group B (CDT 60min), Group C (CDT 90min), Group D (CDT 120min), Group E (CDT 150min), Group F(CDT 180min) and Group G (no CDT) as a control group. TiN coating surface was observed with Atomic Force Microscope(AFM), field emission scanning electron microscopy(FE-SEM) and examined with scratch tester, wear tester. Result: 1. Coating thickness fir each coated group was increased in proportion to coating deposition time. 2. Surface of all coated groups except Group A was homogeneous and smooth. However, surface of none coated Group G had scratch. 3. Adhesion strength for each coated group was increased in proportion to coating deposition time. 4. Wear resistance for each coated group was increased in proportion to coating deposition time. 5. Surface roughness in Group A, B, C was increased in proportion to coating deposition time. But, surface roughness in Group D, E, F was showed decreased tendency in proportion to coating deposition time. Conclusion: According to coating deposition time, mechanical properties of TiN coated film were changed. It was considered that 120 minutes coating deposition time ($1.32{\mu}m$ in coating thickness) is necessary.

• 한국콘텐츠학회논문지
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• 제21권12호
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• pp.918-925
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• 2021

페로브스카이트 태양전지는 기존의 실리콘 태양전지를 대체하는 차세대 태양전지로서, 페로브스카이트 구조를 가진 유-무기 하이브리드 물질을 광 활성층으로 사용하는 태양전지 소자로 고효율, 저가의 용액 공정 및 저온 공정에 유리한 장점들을 가지고 있으며 지난 10년간 빠른 효율 향상을 보여주었다. 이러한 페로브스카이트 태양전지의 상용화 과정에서 대면적 코팅 방법에 대해서 연구개발이 진행되어야 한다. 대면적 페로브스카이트 태양전지 대면적 코팅 방법 중 하나로 슬롯-다이 코팅방법에 대해서 연구 진행하였다. 메니스커스를 이용하여 기판 위를 지나가며 용액을 코팅하는 방법으로 3D printer에 메니스커스를 장착하여 코팅을 할 수 있도록 하였다. 코팅 시 작용하는 변수로는 bed 온도, coating speed, N₂ blowing간격, N₂ blowing 높이, N₂ blowing세기등이 있으며 이를 조절하여 페로브스카이트 흡수층을 제작 진행하였으며, 대면적 소자 제작을 위한 코팅 조건을 최적화 하였다.