• 한국세라믹학회지
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• 제53권1호
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• pp.75-80
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• 2016

Ink-jet printing has become a widespread technology with the society's increase in aesthetic awareness. Especially, ink-jet printing using glazed ceramic ink can offer huge advantages including high quality decoration, continuous processing, glaze patterning, and direct reproduction of high resolution images. Recently, ceramic ink-jet printing has been rapidly introduced to decorate the porcelain product and the ceramic tiles. In this study, we provide an effective method to apply ceramic ink-jet decorations on the glass substrates using a oleophobic coating with perfluorooctyl trichlorosilane. The ink-jet printed patterns were much clearer on the oleophobically coated glass surface than the bare glass surface. The contact angle of the ceramic ink was maximized to the value of $64.0^{\circ}$ on the glass surface, when it was treated with 1 vol% PFTS solution for 1 min. The effects of the printing conditions and firing process on the ink-jet printed patterns on the oleophobically coated glass were also investigated.

• 한국전기전자재료학회논문지
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• 제32권6호
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• pp.483-489
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• 2019

For machine learning techniques, a large amount of high-quality material property data should be accumulated. In this study, several data for an alumina tape casting process were produced with the variables of slurry viscosity, gap size, and coating speed. The alumina tapes were manufactured in the range of 1,000~6,000 cps for slurry viscosity, $300{\sim}1,000{\mu}m$ for gap size, and 0.5~2.0 m/min for coating speed. As a result, the lower the viscosity, coating speed, and gap size, the more pore-free tapes could be manufactured. The viscosity of the slurry limited the minimum thickness of the tape. Green sheets with high packing density were manufactured from the slurry of 100~6,000 cps slurry viscosity, coating speed of 0.5 m/min, and a $300{\sim}500{\mu}m$ gap size.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.181-182
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• 2002

Most recent, Plasma ceramic spray is used on parts of tribosystem, has been investigated on the tribological performance. The application of ceramic coatings by plasma spray has become essential in tribosystems to produce better wear resistance and longer life in various conditions. The purpose of this work was to investigate the wear behavior of $8%Y_2O_3-ZrO_2$ coating due to temperatures of post-spay heat treatment. The plasma-sprayed $8%Y_2O_3--Zirconia$ coating was idiscussed to know the relationship between phase transformations and temperatures of post- spray heat treatment. Wear tests was carried out with ball on disk type on normal load of 50N, 70N and 90N under room temperature. The transformation of phase and the value of residual stress were measured by X-ray diffraction method(XRD). Tribological characteristics and wear mechanisms of coatings was observed by SEM. The tribologieal wear performance was discussed a point of view for residual stress. Consequently. post-spray heat treatment plays an important role in decreasing residual stress. Residual stress in coating system has a significant influence on the wear mechanism of coating.

• 토지주택연구
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• 제11권3호
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• pp.75-82
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• 2020

The urban heat island phenomenon that accelerates global warming has always been controversial when summer heatwaves have occurred since it was first investigated and described by Luke Howard in the 1810s. In Korea, since 2014, government have been interested in Cool Roof and painted white coating on the rooftops of the aging and weak buildings, and the cool roof business has expanded nationwide. However, the roof occupies 20-25% of the entire city surface, much less than 37-45% of the pavement area consisting of roads, parking lots and sidewalks, there is a need to expand the policy of Cool Pavement as a way to reduce the urban heat island phenomenon. Domestic cities are high-rise buildings centered on apartments, and the area occupied by outer walls is larger than that of rooftops compared to foreign low-rise buildings. Therefore, as a way to reduce the urban heat island phenomenon, there is a need for a policy to expand the Cool Roof in buildings and use Cool Wall in parallel. Therefore, this study aims to present the expansion of Cool Wall in buildings and Cool Pavement in urban areas, expanding the installation range of Cool Roof, by comparing and reviewing the thermal characteristics of eco-friendly ceramic coating with excellent thermal proof performance and coatings used for roof waterproofing.

• 한국세라믹학회지
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• 제29권8호
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• pp.667-673
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• 1992

The alumina-zirconia composite powders of core particle ZrO2 coated with Al2O3 were prepared by the hydrolysis-deposition of the mixed aluminum salt solution of Al2(SO4)3-Al(NO3)3-Urea. The effects of hydrolysis reaction and coating parameters on characteristics of coated powders and composites were also investigated. The degree of coating could be estimated from the ratio of tetra-/mono-ZrO2 present at the room temperature after heat-treating coated powders at 120$0^{\circ}C$ and the result of TEM observations. When the content of ZrO2 in the dispersed coating system, the coating time, and the volume ratio of water/solution were 50 mg/g, 180 min, and 5, respectively the coating efficiency was maximum (the ratio of tetra-/mono-ZrO2 was 87/13). The relative densities of coated Al2O3-ZrO2 composites sintered at 1$650^{\circ}C$ for 4 hrs were about 91~98% and the maximum ratio of tetra-/mono-ZrO2 in Al2O3-20wt% ZrO2 composites was 62/38.

• 한국세라믹학회지
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• 제35권1호
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• pp.48-54
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• 1998

Part I에 이어서 질화규소로 코팅된 질화규소-질화붕소 시스템에 있어서 접촉하중에 의한 코팅층의 파괴에 대한 코팅층의 두께의 영향을 고찰하였다. 코팅층과 기판층간의 elastic/plastic mismatch가 큰 경우 코팅층의 균열생성을 방지하는 어느 임계 두께가 존재한다는 사실을 발견하였으며, mismatch가 감소할수록 이러한 요구 임계두께가 감소하였다. 또한 가해진 하중이 증가할수록 요구 임계두께는 증가하여야 함을 알 수 있었다. 따라서 코팅층의 파괴를 방지하기 위해서는 코팅층과 기판층간의 mismatch와 사용환경(가해지는 하중)을 고려한 적정 임계두께늬 설계가 요구된다.

• 전기학회논문지P
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• 제66권2호
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• pp.94-97
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• 2017

A method of improving the anti-fouling characteristics of porcelain insulators was proposed in this study. Functional coating was performed as a method of reducing the surface contamination of the porcelain insulators. The functional coating was applied on a ceramic substrate, which has the same material as the porcelain insulators. After coating the ceramic substrate 2, 3, 4, and 5 times alternately in the horizontal and vertical directions, the surface characteristics according to the thickness of the coating film were analyzed. The optimal process was selected to coat the surfaces of the post insulators and long rod insulators, which are the representative porcelain insulators. After coating, heat treatment was performed for 1 hour at $200^{\circ}C$ in a furnace to secure the durability of the coating film. Compared to the uncoated insulators, the insulators with the functional coating showed significantly improved anti-fouling characteristics as well as excellent adhesion to the coated insulator surface.

• 한국세라믹학회지
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• 제47권6호
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• pp.633-637
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• 2010

In this study, lithium manganese oxide spinel ($LiMn_{1.9}Fe_{0.1}Nb_{0.0005}O_4$) as a cathode material of lithium ion secondary batteries is synthesized with spray drying, and in order to increase its crystallinity and electrochemical properties, the granulated $LiMn_{1.9}Fe_{0.1}Nb_{0.0005}O_4$ particle surface is coated with lithium titanium oxide spinel ($Li_4Ti_5O_{12}$) through a sol-gel method. The granulated particles present a higher tap density and lower specific surface area. The crystallinity and discharge capacity of the $Li_4Ti_5O_{12}$ coated material is relatively higher than uncoated material. With the coating layer, the discharge capacity and cycling stability are increased and the capacity fading is suppressed successfully.

• 대한안전경영과학회지
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• 제7권1호
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• pp.211-222
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• 2005

The ceramic forming materials are getting more important recently since they are used widely in repairing metal structures, welded metal structures and mechanical components etc. The determination of elastic constants for ceramic coating materials takes much time and efforts in experiment due to the brittleness of ceramic material itself. The aim of this research is to determine the Young's Modulus for ceramic metal coating material. In order to achieve the goal, the hybrid method which uses impulse hammer technique for experimental method and modal analysis of finite element method for computational method was used. The results show good agreement with existing experimental data on Young's Modulus.

• Structural Engineering and Mechanics
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• 제4권6호
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• pp.679-702
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• 1996

The finite element method is employed in conjunction with micromechanical modelling in order to assess the performance of ceramic thermal barrier coatings applied to structural components. The study comprises the conditions of the deposition of the coating by plasma spraying as well as the thermal cycling of the coated component, and it addresses particularly turbine blades. They are exposed to high temperature changes strongly influencing the behaviour of the core material and inducing damage in the ceramic material by intense straining. A concept of failure analysis is discussed starting from distributed microcracking in the ceramic material, progressing to the formation of macroscopic crack patterns and examining their potential for propagation across the coating. The theory is in good agreement with experimental observations, and may therefore be utilized in proposing improvements for a delayed initiation of failure, thus increasing the lifetime of components with ceramic thermal barrier coatings.