• Title/Summary/Keyword: dip-coating

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Effects of Annealing Temperature on Properties of Al-Doped ZnO Thin Films prepared by Sol-Gel Dip-Coating

  • Jun, Min-Chul;Koh, Jung-Hyuk
    • Journal of Electrical Engineering and Technology
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    • v.8 no.1
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    • pp.163-167
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    • 2013
  • Aluminum doped zinc oxide (AZO) thin films have been prepared on the glass substrates (Corning 1737) by sol-gel dip-coating method employing zinc acetate and aluminum chloride hexahydrate for the transparent conducting oxide (TCO) applications. 1 at% Al was doped to the ZnO thin films. The effects of post-heating temperature on the crystallization, optical and electrical properties of the AZO films have been investigated. Experimental results showed that post-heating temperature affected the microstructure, electrical resistance, and optical transmittance of the AZO films. From the X-ray diffraction analysis, all films have hexagonal wurtzite crystal structure. Optical transmittance spectra of the AZO films exhibited transmittance higher than about 80% within the visible wavelength region and the optical direct band gap ($E_g$) of these films was increased with increasing post-heating temperature. A minimum resistivity of $2.5{\times}10^{-3}{\Omega}cm$ was observed at $650^{\circ}C$.

Effect of oxidation-Reduction Hating Conditions on Coating Adherence of Hot-Dip Galvanized Steel Containing silicon (Si함유강의 용융아연 도금부착성에 미치는 산화-환원 열처리 영향)

  • 김종상
    • Journal of the Korean institute of surface engineering
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    • v.31 no.2
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    • pp.101-108
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    • 1998
  • The effect of oxidation-reduction heating conditions on coating adherence of hot-dip galvanized steel containing silicon has beeninvestigated. The presence of a stbke sillicon oxide formed on the steel surface has been shown to be very detrimenal to proper wetting by liquid zinc. When the steel has more than the critical sillicon content neeled to from a stable external oxide, the use of oxidation-reduction method has been found successful in obtaining a good quality, coated product with excellence adhreence. This can be explained by the formation of an iron oxide. The iron oxrtion of the scale is reduced, leaving the stable oxides dispersed in a fresh metallic iron surface layer. This reduced iron surface is easily wetted by the liquid zinc and excellent adherence is obtained.

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Fabrication of $TiO_2-CeO_2$ Composite Membranes with Thermal Stability

  • Bae, Dong-Sik;Han, Kyong-Sop;Park, Sang-Hael
    • The Korean Journal of Ceramics
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    • v.1 no.4
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    • pp.219-223
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    • 1995
  • Ceramic membranes of the supported $TiO_2-CeO_2$ were prepared by dip-coating method on an $\alpha-Al_2O_3$ porous substrate. The mean pore diameter of an alumina support was 0.125 um. The mean particle diameter of $TiO_2-CeO_2$ top layer varied with firing temperature and ranged from 20 to 85 nm. The thermal stability of the composite membranes was studied from their surface microstructure after calcination at $600-900^{\circ}C$. The supported $TiO_2-CeO_2$ composite membranes exhibited much higher heat resistance than the $TiO_2$ membrane.

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A study on the preparation of phthalocyanine optoelectric thin films (프탈로시아닌계 광전도성 유기박막의 제조에 관한 연구)

  • 박구범;조기선;이덕출
    • Electrical & Electronic Materials
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    • v.7 no.5
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    • pp.409-416
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    • 1994
  • A double layered photoreceptor using phthalocyanine dye was made by dip-coating method. The under cutting layer(UCL) was coated with A1$\_$2/O$\_$3/ or polyamide, and the charge generation layer(CGL) was formed by .tau.-type metal-free phthalocyanine. The oxadiazole was used as a charge transport layer(CTL) and polycarbonate and poly(vinyl butyral) was employed as a host polymer. The .tau.-H$\_$2/Pc had an absorption peak around 780nm, which coincided with the emitting wavelengths of GaAlAs diode lasers. Maximum charge acceptance of CTL that gives thickness of 12.mu.m was -900V by corona charge of -6.0kV. In photo-induced discharge measurements, residual potential was less than -20V and sufficient for ordinary use, and sample films using of poly(vinyl butyral) was showed good charge retention. In printing test, drum that was employed polycarbonate as a host polymer showed the good print quality.

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Reflectivity of Sn Solder for LED Lead Frame

  • Xu, Zengfeng;Gi, Se-Ho;Park, Sang-Yun;Kim, Won-Jung;Jeong, Jae-Pil
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2011.05a
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    • pp.184-185
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    • 2011
  • In this study, in order to obtain a high reflectivity for the LED lead frame, tin dip coating and tin plating were conducted respectively, and wettability of LED lead frame with tin solder also was tested by wetting balance tester. A Cu sheet was plated in Cu brighten electroplating bath and followed by immersion in a Sn electro-less plating bath [1]. On the other hand, in the dip coating process, a Cu sheet was dipped into molten tin. In the progress of wetting test, besides wetting balance curve, the maximum measured force($F_m$), the maximum withdrawal force($F_w$) and zero-cross time($t_0$) were obtained in various temperatures. With the maximum withdrawal force, the surface tension was calculated at different temperatures. The Cu sheet plated with bright Cu and Sn show a silver bright property while that of Cu dipped with Sn possessed a high reflectance density of 1.34GAM at $270^{\circ}C$.

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Application of Coating Thickness Control System (도금 두께 제어시스템의 개발 적용)

  • Choi, Il-Seop;Yoo, Seung-Ryul;Park, Han-Ku;Kwak, Young-Woo;Kim, Sang-Jun
    • Proceedings of the KIEE Conference
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    • 1995.07b
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    • pp.892-894
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    • 1995
  • This paper deals with developmeant and application of coating thickness control system in hot dip galvanizing process. According to the line conditions, such as line speed, strip size and target coating weight, a predictive preset model sets the initial oprating conditions. Referring the zine coating informations from the gauge, mean coating value controller adjusts the chamber pressure and horizontal distance between strip and air knife, while coating deviation controller adjusts the lip gap profile of the air knife. All adaptive gains are interactively calculated by numeric models based on the theoretical analysis. The operating result with this system effectively reduces the coating deviation in transverse direction as well as in longitudinal direction.

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Development of Alkali Metal Thermal-to-Electric Converter Unit Cells Using Mo/TiN Electrode

  • Seog, Seung-won;Choi, Hyun-Jong;Kim, Sun-Dong;Lee, Wook-Hyun;Woo, Sang-Kuk;Han, Moon-Hee
    • Journal of the Korean Ceramic Society
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    • v.54 no.3
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    • pp.200-204
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    • 2017
  • Molybdenum (Mo), an electrode material of alkali metal thermal-to-electric converters (AMTEC), facilitates grain growth behavior and forms Mo-Na-O compounds at high operating temperatures, resulting in reduced performance and shortened lifetime of the cell. Mo/TiN composite materials have been developed to provide a solution for such issues. Mo is a metal that possesses excellent electrical properties, and TiN is a ceramic compound with high-temperature durability and catalytic activity. In this study, a dip-coating process with an organic solvent-based slurry was used as an optimal coating method to achieve homogeneity and stability of the electrodes. Cell performance was evaluated under various conditions such as the number of coatings, ranging from 1 to 3 times, and heat treatment temperatures of $800-1100^{\circ}C$. The results confirmed that the cell yielded a maximum power of 9.99 W for the sample coated 3 times and heat-treated at $900^{\circ}C$.

Comparison of Antibacterial Ability of Air Filter Media Treated with a Natural Antibacterial Agent by Three Treatment Methods (항균성 천연물질의 도포방법에 따른 에어필터 여재의 항균 특성 비교)

  • Park, Sun Young;Jung, Jae Hee;Hwang, Gi Byung;Bae, Gwi-Nam;Kim, Yong Pyo;Nho, Chu Won
    • Journal of Korean Society for Atmospheric Environment
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    • v.29 no.2
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    • pp.125-134
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    • 2013
  • Various antimicrobial technologies have been developed to inactivate bioaerosols in indoor environments. In this study, air filter media were treated with a natural antibacterial agent of Sophora flavescens in order to inactivate the bacteria collected on the air filter. Three treatment methods were applied to manufacture the test antibacterial air filter media: electrospray, nebulization and dip-coating methods. In case of electrospray and nebulization processes, the size distribution of aerosolized natural antibacterial agent was measured using a scanning mobility particle sizer. Staphylococcus epidermidis bacteria were aerosolized to test inactivation of the filter media treated with a natural antibacterial agent. The pressure drop and the antibacterial efficiency of the filter media increased with increasing the mass loading of natural antibacterial agent in each treatment method. The antibacterial efficiency per loaded antibacterial agent mass by the electrospray method was the highest and the filter treated by the dip-coating method was the lowest among three treatment methods.