• 반도체디스플레이기술학회지
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• 제13권3호
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• pp.51-55
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• 2014

Ni-CNT(Carbon Nanotubes) composite coating is often used for the surface treatment of mechanical/electronic devices to improve the properties of the Ni coating. For the Ni-CNT coating, the dispersion of CNT fibers is a critical process. In this study, ultrasonic treatment instead of the conventional ball milling was attempted as a dispersion method for the electroless Ni-CNT coating. SEM-EDX analysis was performed and contact angle, sheet resistance, and micro-hardness were measured. Results showed that the ultrasonic treatment was comparable to the ball milling, as a dispersion method, but the difference was negligible. However, combined ball milling and ultrasonic treatment(double treatment) showed much improved micro-hardness value, above 350Hv(close to the value obtained by the Ni-CNT electroplating). In addition, electroless Ni-CNT(double-treated) coatings formed on the thin Ni film deposited by the electroless plating(double coating) showed better mechanical properties. Thus, double treatment and double coating are suggested as an improved electroless Ni-CNT coating method.

• 반도체디스플레이기술학회지
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• 제17권4호
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• pp.80-85
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• 2018

The present investigation on optical fiber mass manufacturing features the computational modeling and simulation on a double layer liquid coating process on glass fiber surface. The computational model employs a simplified geometry of typical fiber coating system which consists of primary and secondary coating dies along with secondary coating cup. The viscous dissipation in coating flow is incorporated into the double layer coating process simulations. Heavy temperature dependence of coating liquid viscosity is also considered in the model. The computational results found that the effects of viscous dissipation on both primary and secondary coating layer thicknesses are highly significant at higher drawing speed. Several important coating process parameters such as supply temperature and pressure of primary and secondary coating liquids are investigated and discussed in order to appreciate how those parameters affect the double layer coating layer thickness on fast moving glass fiber.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 춘계학술발표논문집
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• pp.124-131
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• 2006

It is well known that smoother surface in substrate for coating or converting can obtain better results. Generally paper substrate is taking machine calendar process in papermaking system to give more uniformity and to get better coating runnability. This paper was prepared to find better idea for obtaining smoother surface after precalendering precoated paper as a substrate of double coating system. It was shown precalendering had effect on roughness improvement for precoating layer but was difficult to say it was effected to supercalendering results for double coating. The porosity and ink evaluation with precalendered double coated paper is needed to identify more essential clue for precalendering effect.

• 한국인쇄학회지
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• 제9권1호
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• pp.27-44
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• 1991

In this research, double-layered photoconductor consist of the carrier generation layer(CGL) of ${\varepsilon}$ type copper phthalocyanine thin film by an aqueous coating method and the carrier transport layer(CGL) of polyvinyl carbazol(PVK) by spin coating. We inverstigated effect of the surfactant solution and cathod electrolysis to the crystal type of ${\varepsilon}$-CuPc in CGL with TEM, SEM and X-ray diffraction spectroscopy and studied the mechanism of an aqueous coating for the preparation of CGL. The effect of the washing of CGL about the electrophotographic characteristics of the ${\varepsilon}$-CUPC/PVK double-layered photoconductors is studied also.

• 펄프종이기술
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• 제46권3호
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• pp.73-80
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• 2014

In this study, in order to investigate the influence of insolubilizer on the double coating structure, we carried out basic research related to the double coating formulation with four insolubilizers having various chemical types such as amino aldehyde, glyoxal and two metallic salts. It was found that although the four insolubilizers showed similar results on optical and surface properties of the coated papers, they gave different results in the printabilities of the coated papers since coating structure was significantly influenced by different reacting mechanism of the insolubilizers. Three of the insolubilizers (glyoxal, two metallic salts) showed better results than amino aldehyde type one when they were applied to top coating formulation. Metallic salts type insolubilizers showed good results in the print gloss when it was applied to top coating formulation. It was believed that amino aldehyde type insolubilizer applied top coating formulation showed good both of dry-pick and wet-pick strength.

• 펄프종이기술
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• 제30권4호
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• pp.79-84
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• 1998

The process of double coating consists of bottom coating using relatively coaser pigments to improve characteristics of base paper and top coating using finer pigments to cover unevenness of the bottom coating and to give various function of the coated paper. The structure of precoating is influenced not only by its components, but also characteristics of base paper, Moreover pore size and its size distribution of precoating are expected to influence the top coating properties, but this is not well understood. Coating and printing operations involve the application of pigmented fluid on top of a porous substrate. The porosity of the substrate has been shown to influence the properties of the coating, but a good understanding of the mechanisms is lacking in the literature. The role of pore size and void volume on top coating structure is unclear.

• 반도체디스플레이기술학회지
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• 제18권3호
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• pp.12-18
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• 2019

The protective double layer polymer coatings on silica optical fibers are realized by wet-on-wet liquid coating process and they play an important role in final quality of mass produced optical fibers. This numerical study aims to analyze the effects of secondary coating die design parameters by employing two dimensional axisymmetric model of coating cup and coating die geometry and computational fluid dynamics simulations which include temperature dependent viscosity of polymer coating liquids and viscous dissipation heating. Under high speed fiber drawing conditions and pressurized coating liquid supply, the effects of converging die angle are investigated in order to appreciate the change of coating liquid flow patterns such as flow recirculation zone near coating die as well as primary and secondary coating layer thicknesses. The auxiliary coating die to converging coating die is also tested and the results find that this concept is advantageous in achieving stable double layer coatings on silica glass fiber.

• 한국표면공학회지
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• 제51권3호
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• pp.164-171
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• 2018

In this study, we have fabricated pure titanium (Ti)/hydroxyapatite (HA) double layer coating on medical grade PEEK from magnetron sputtering system, an investigation was performed whether the surface can be had more improve bio-active for orthopedi/dental applications than that of non-coated one. Pure Ti and HA coating layer were obtained by a radio-frequency and direct current power magnetron sputtering system. The microstructures surface, mechanical properties and wettability of the pure Ti/HA double layer deposited on the PEEK were analyzed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), nano-indentation, and contact angle test. According to the EDS and XRD results, the composition and crystal structure of pure Ti and HA coated surface were verified. The elastic modulus and hardness value were increased by pure Ti and HA coating, and the pure Ti/HA double layer coating surface has the highest value. The contact angle showed higher value for pure Ti/HA double layered coating specimens than that of non-coated (PEEK) surface.

• 전기화학회지
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• 제25권1호
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• pp.32-41
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• 2022

Various steps in the electrode production process, such as slurry mixing, slurry coating, drying, and calendaring, directly affect the quality and, consequently, mechanical properties and electrochemical performance of electrodes. Herein, a new method of slurry coating is developed: Double-coated electrode. Contrary to single-coated electrode, the cathode is prepared by double coating, wherein each coat is of half the total loading mass of the single-coated electrode. Each coat is dried and calendared. It is found that the double-coated electrode possesses more uniform pore distribution and higher electrode density and allows lesser extent of particle segregation than the single-coated electrode. Consequently, the double-coated electrode exhibits higher adhesion strength (74.7 N m^-1) than the single-coated electrode (57.8 N m^-1). Moreover, the double-coated electrode exhibits lower electric resistance (0.152 Ω cm^-2) than the single-coated electrode (0.177 Ω cm^-2). Compared to the single-coated electrode, the double-coated electrode displays higher electrochemical performance by exhibiting better rate capability, especially at higher C rates, and higher long-term cycling performance. Despite its simplicity, the proposed method allows effective electrode preparation by facilitating high electrochemical performance and is applicable for the large-scale production of high-energy-density electrodes.

• 설비공학논문집
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• 제9권3호
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• pp.300-311
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• 1997

A theoretical method was developed to analyze the effect of low-$\varepsilon$ coatings which have influence on thermal performance of vacuum windwo glazing and double pane glazing. The overall heat transfer coefficient(U) value and thermal performance were analyzed by theroretical method on various kins of windows. TRNSYS program was used to analyze total heating and cooling energy consumption on the model building which has various windows. As the result, better thermal insulation can be achieved on the vacuum window glazing than double pane glazing when low-$\varepsilon$ coating was done on the surface of glass. Total heating and cooling energy consumption was almost same on the double pane window glazing but was lessened on the vacuum window glazing when the window size of south direction increased. Therefore, low-$\varepsilon$ coating was very necessary for vacuum window glazing in order to improve thermal insulation performance and efficient energy conservation can be achieved by vacuum window glazing at the real building which has large window.