• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2003년도 춘계학술발표논문집
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• pp.80-92
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• 2003

The water retention of coating colors can be accurately measured by devices such as an AA-GWR water retention meter whose principle of measurement is based on pressure filtration of coatings under an externally applied air pressure over a certain period of time. It was hypothesized that such devices could be also used to determine the immobilization solids(IMS) of coating colors by determining a sudden drop in the rate of dewatering, that is, a sudden change in the drainage curves. To test this hypothesis, the immobilization solids of coating colors containing various thickeners and water retention additives at different levels were first accurately measured by a modified immobilization tester based on the well-known gloss drop method, and then their values were compared with those obtained by an AA-GWR water retention tester. They agreed very well and showed that the mean of the solids differences is 0.36% in the IMS points between both methods. This good agreement was not surprising because both test methods are based on the same end-point, that is, the immobilization solids point at which menisci begin to form at the coating surface. Theoretical considerations supporting this new method for measuring the immobilization solids of coating colors are presented and some recommendations for the test method are discussed. Also, the effect of various thickeners and water retention additives on the properties and printability of coated papers is discussed.

• Corrosion Science and Technology
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• 제5권1호
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• pp.33-38
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• 2006

Current coating practice requires the thickness of anti-corrosion organic coatings to be over $250{\mu}m$ for immersion parts of ships and offshore structures and the corrosion resistance of these coatings has been evaluated by destructive and qualitative analysis. Recently, Electrochemical Impedance Spectroscopy(EIS) method has been employed, as an alternative, to evaluate corrosion resistance of organic coatings. This method is characterized as being nondestructive, reproducible, and quantitative in evaluating aging of organic coatings. In this study, EIS method was adopted to quantitatively and effectively select the coating systems having optimized protective performance. Evaluations of several epoxy and epoxy/polyurethane coating systems typically used for ships and offshore structures were carried out in wet($50^{\circ}C$, $90^{\circ}C$) and dry(room temp.) environments to accelerate the degradation of the organic coatings. These results were compared with the conventional scribed(scratched) test results. The plausible prediction model for determining the remaining life-time of coating systems was also proposed based on variations of impedance data, FT-IR and $T_g$ measurements results.

• Bulletin of the Korean Chemical Society
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• 제29권2호
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• pp.463-466
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• 2008

We report a method to increase the surface area of the titania films used as the anodes of dye-sensitized solar cells (DSSCs) by applying additional titania-coating. The modification was achieved by spin-coating a coating solution that contained a surfactant with a titania source onto the titania electrodes, followed by calcination. Previous similar attempts without a surfactant all reported decreased surface areas. We fabricated DSSCs by using the modified titania films as the anode and measured their performances. The increased surface area increased the amount of adsorbed dyes, which resulted in increased current densities. At the same time, the titania-coating increased both the open-circuit voltage and the current density by reducing the charge-recombination rates of the injected electrons, similar to the results of literatures. Therefore, our method shows an additional mechanism to increase the current density of DSSCs in addition to the other mechanisms of surface modifications with titania-coatings.

• 전기학회논문지
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• 제58권11호
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• pp.2214-2218
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• 2009

Dye-sensitized solar cell (DSC) has been considered as a possible alternative to current silicon based p-n junction photovoltaic devices due to its advantages of high efficiency, simple fabrication process and low production cost. Numerous researches for high efficient DSC in the various fields are under way even now. Among them, the compact layer, which prevents the back electron transfer between transparent conductive oxides and the redox electrolyte, is fabricated by various methods such as a ZnO dip-coating, $TiCl_4$ dip-coating, and Ti sputtering. In this study, we tried to fabricate the $TiO_2$ compact layer by the spin-coating method using aqueous $TiCl_4$ solution. The effect of the spin-coating method was checked as compared with conventional dip-coating method. As a result, DSC with a spin-coated compact layer had 33.4% and 6% better efficiency than standard DSC and DSC with a dip-coated compact layer.

• Macromolecular Research
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• 제17권11호
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• pp.907-911
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• 2009

To improve the moisture stability of the $CaS:Eu^{2+}$ red phosphor, surface coatings with silica nanoparticles were performed using five different methods, i.e., $P_1$, $P_2$, $P_3$, $P_4$, and $P_5$. The phosphors were coated with silica nanoparticles using a dip coating method ($P_1$) and sol-gel method ($P_2$). The phosphors were coated using a solution containing silica nanoparticles and poly(1-vinyl-2-pyrrolidone), PVP, $(P_3$). The phosphors were also coated with silica nanoparticles by reacting with the 1-vinyl-2-pyrrolidone (VP) monomer ($P_4$) or by reacting with mixtures containing VP and tetraethylorthosilicate ($P_5$). A decrease in the photoluminescence (PL) intensity was observed regardless of the coating methods. However, the moisture stability of the phosphors was enhanced by the coating when aged in a temperature-controlled humidity chamber. Among these methods, the $P_4$ (or $P_5$) method exhibited the greatest increase in moisture stability of the phosphors. The coated phosphors showed a relatively constant intensity with aging time, whereas the uncoated phosphor showed a decrease.

• 공업화학
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• 제32권5호
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• pp.497-503
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• 2021

본 연구에서는 악취가스 및 휘발성 유기 화합물을 산화 제거하기 위한 백금/티타니아를 허니컴 및 메탈폼 담체에 코팅하는 방법을 확인하였다. 다양한 방법 중 파우더 코팅과 나노 코팅에 대한 비교를 수행하였다. SEM/EDX (Scanning Electron Microscopy/Energy Dispersive X-ray spectroscopy) 분석은 허니컴 및 메탈폼의 표면 상태 및 노출된 백금 성분비를 조사하는데 사용되었다. 또한, 촉매 코팅 방법에 따른 톨루엔, 트리메틸아민, 아이소프로필 알코올의 제거 성능을 비교하였다.

• 품질경영학회지
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• 제42권2호
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• pp.179-187
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• 2014

Purpose: Since several problems were found when present non-conducting metal coating process was applied to mass production, we study and develop to improve those problems. Methods: In this paper, a couple of analysis methods such as surface hardness, XPS spectrum analysis, morphology, and reflection ratio were used. Results: This paper suggest a new possibility of Non-conducting thin metal coating method that has quality of mass production phase without UV coating process. Conclusion: By the result of analysis, we can set optimized process conditions of the electro deposition coating using electron beam.

• 한국정밀공학회지
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• 제30권8호
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• pp.802-808
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• 2013

Thermal barrier coating (TBC) is used to protect substrates and extend the operating life of gas turbines in power plant and aeronautical applications. The major causes of failure of such coatings is spallation, which results from thermal stress due to a thermal expansion coefficient mismatch between the top coating and the bond coating layers. In this paper, the effects of the material properties and the thickness of the top coating layer on thermal stresses were evaluated using the finite element method and the equation for the thermal expansion coefficient mismatch stress. In addition, we investigated a design technique for the top coating whereby thermal resistance is exploited.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.348-348
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• 2009

The conductive coating method is used for various industrial fields. For example, Sputtering process is used to coat ITO layer in LCD or OLED panel manufacture process and fabricate a base layer of substrate of an electric printing device. However, conventional coating processes (beam sputtering, spin coating etc.) has a problems in the industrial manufacturing process. These processes have a very high cost and critical manufacturing environment as a vacuum process. Recently, many researchers have proposed various printing process instead of conventional coating processes. In this paper, we propose an ESD printing process in ITO coating layer and apply to fabricate a conductive coating film. Furthermore, the effect of the nozzle and also the applied voltage on different configuration of the nozzle head was also studied for better understanding of the Electro Static deposition process.

• 한국표면공학회지
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• 제48권6호
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• pp.349-353
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• 2015

In this paper, arc thermal spray coating was conducted onto the SS400 steel using Inconel 625 wires in order to improve the durability of marine steel structures, and then investigated cavitation damage behavior of Inconel 625 coating layer in sea water. For the Inconel 625 coating layer, surface hardness appeared similar to that of existing high velocity oxy-fuel coating technology with 380~480 HV, but the porosity of about 6 % was larger relatively. During the cavitation experiment, pit damages were originated and grown at the rough surface and pore defect area of Inconel 625 coating layer. And, after the 72 hours of experimental time, weight loss of Inconel 625 coating layer exhibited gradually increasing tendency due to surface damage effect of the undercut.