• Journal of the Korean Society for Heat Treatment
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• v.34 no.3
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• pp.107-115
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• 2021

Al-Si coated boron steel has been widely used as commercial hot stamping steel. When the steel is heated at 900~930℃ for 5 min in an electric furnace, thickness of the coating layer increases as a consequence of formation of intermetallic compounds and diffusion layer. The diffusion layer plays an important roll in blunting the propagation of crack from coating layer to base steel. Change in microstructure and coating layer of Al-Si coated boron steel after conductive heating with higher heating rate than electric furnace has been investigated in this study. Conductive-heated steel showed the martensitic structure with vickers hardness of 505~567. Both intermetallic compounds in coating layer and diffusion layer were not observed in conductive-heated steel due to rapid heating. It has been found that the conductive-heating consisting of rapid heating to 550℃ which is lower than melting point of Al-Si coating layer, slower heating to 900℃, and then 1 min holding at 900℃ is effective in forming intermetallic compound in coating layer and diffusion layer.

• Design & Manufacturing
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• v.13 no.3
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• pp.1-11
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• 2019

Recently, studies on the development of flexible electronic devices by combining flexible materials and a conductor have been actively performed as interest in wearable devices. Especially, carbon nanotubes (CNT) or graphene coating have been used to construct a circuit to induce improvement in flexibility and rigidity. Various technologies have been developed in the surface coating of conductive materials, which are key to the manufacture of flexible electronic devices. Surface coating products with 3D coating and micro-patterns have been proposed through electrospinning, electrification, and 3D printing technologies. As a result of this advanced surface coating technology, there is a growing interest in manufacturing gradient conductive surfaces. Gradient surfaces have the advantage that they are adapted to apply a gentle change or to inspect optimum conditions in a particular region by imparting continuously changing properties. In this study, we propose a manufacturing technique to produce a continuous gradient conductive surface by combining a partial stretching of elastomer and a conductive material coating, and introduce experimental results to confirm its performance.

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.387-392
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• 2018

Various technical approaches and concepts have been proposed to develop conductive super-hydrophobic (SH) surfaces. However, most of these approaches are not usable in practical applications because of insufficient adhesion and cost issues. Additionally, durability and uniformity issues are still in need of improvement. The goal of this research is to produce a large-area conductive SH surface with improved adhesion performance and uniformity. To this end, carbon nanotubes (CNT) with a high aspect ratio and elastomeric polymer were utilized as a conductive filler and matrix, respectively, to form a coating layer. Additionally, nanoscale silica particles were utilized for stable implementation of the conductive SH surface. To improve the adhesion properties between the SH coating layer and substrate, pretreatment of the substrate was conducted by utilizing both wet and dry etching processes to create specific organic functional groups on the substrate. Following pretreatment of the surface, a zirco-aluminate coupling agent was utilized to enhance adhesion properties between the substrate and the SH coating layer. Raman spectroscopy revealed that adhesion was greatly improved by the formation of a chemical bond between the substrate and the SH coating layer at an optimal coupling agent concentration. The developed conductive SH coating attained a high electromagnetic interference (EMI) shielding effectiveness, which is advantageous in self-cleaning EMI shielding applications.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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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.

• Fibers and Polymers
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• v.3 no.1
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• pp.24-30
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• 2002

Wool yams were coated with conducting Polypyrrole by chemical synthesis methods. Polymerization of pyrrole was caned out in the presence of wool yarn at various concentrations of the monomer and dopant anion. The changes in tensile, moisture absorption, and electrical Properties of the yam upon coating with conductive polypyrrole are Presented. Coating the wool yams with conductive Polypyrrole resulted in higher tenacity, higher breaking strain, and lower initial modulus. The changes in tensile properties are attributed to the changes in surface morphology due to the coating and reinforcing effect of conductive Polypyrrole. The thickness of the coating increased with the concentration of p-toluene sulfonic acid, which in turn caused a reduction in the moisture regain of the wool yin. Reducing the synthesis temperature and replacing p-toluenesulfonic acid by anthraquinone sulfonic acid resulted in a large reduction in the resistance of the yam.

• Journal of the Semiconductor & Display Technology
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• v.13 no.1
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• pp.19-25
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• 2014

This study demonstrates transparent electrodes with characteristics desirable for touch screen panels using carbon nanotubes (CNTs). This has been accomplished by depositing CNTs on glass substrates via spray coating and then depositing thin conductive polymer films on the CNTs via spin coating. For all of the samples, such as CNTs, conductive polymers, and polymer-coated CNTs, the surface morphologies, sheet resistances, visible transmittances, chromatic properties are characterized as functions of their preparation conditions, such as the spray times for CNTs and the spin speeds for conductive polymers. The experimental results confirm that only the polymer-coated CNTs can satisfy all of the requirements that are required for electrodes of touch screen panels, such as the sheet resistance lower than $100{\Omega}/sq$, the visible transmittance higher than 80 %, and the yellowness smaller than 1.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.8
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• pp.673-680
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• 2015

A roll-to-roll (R2R) continuous manufacturing system for a carbon-nanotube (CNT)-/silver-nanowire (AgNW)- based large-area transparent conductive film was introduced in this study. The systemic guidelines of the R2R slot-die coating process including roll eccentricity, wrap angle, pump accuracy, and blower influence were discussed. To simulate the coating phenomenon, we investigated the governing parameters of the coating process by incorporating the estimated relative thickness that was defined by combining the viscocapillary model and volume model. By using experimental and mathematical approaches, an excellent transparent conductive layer with a $40{\Omega}/{\Box}$ sheet resistance and 88 % transmittance was obtained; moreover, a dimensionless number identifies the correlation between the transparent conductive film and the anti-reflection film.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.57-60
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• 2009

The conductive coating method was used for a various industrial fields. For example, Sputtering process is using to a coat of ITO layer in LCD or OLED panel manufacture process and fabricate a base layer of substrate of an electric printing device. However, conventional coating process (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 were proposed a various printing process instead of conventional coating process. In this paper, we propose an ESD printing process in ITO coating layer and apply to fabricate a conductive coating film. Ours transparent electrode had a surface resistance of about $66{\Omega}/{\square}$ and transparent of 74% in the wavelength of 500nm. This transparent electrode manufacturing process will be applied to Roll-to-Roll process. In addition, we developed roll printing process system for the next generation flexible solar cell.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.73-79
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• 2013

Waterborne polyurethane dispersion (WPUD) was synthesized from polycarbonate diol (PCD), isophorone diisocyanate (IPDI) and dimethylol propionic acid (DMPA) as starting materials. Then, waterborne acrylic polyurethane dispersion (AUD) was synthesized by reacting the WPUD with an acrylate monomer, methyl methacrylate (MMA). Subsequently, the AUD was mixed with multi-walled carbon nanotube (MWCNT) to yield a conductive coating solution, and the mixture was coated on the polycarbonate substrate. With increasing the amount of MMA in the AUD, the pencil hardness, abrasion resistance and chemical resistance of the coating films were improved, but the electrical conductivity of the coating films was decreased. On the other hand, the pencil hardness, abrasion resistance and chemical resistance of coating films were decreased, but the electrical conductivity was enhanced with increasing the amount of MWCNT in the conductive coating solutions.

• Journal of the Korean Ceramic Society
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• v.35 no.11
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• pp.1155-1161
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• 1998

We have studyed the surface electric resistiance for inner conductive film consisted of graphite and iron oxide by coating the conductive paint on inner face of 28" wide CRT funnel and have evaluated the working properties of 28" wide CRT according to the surface electric resistiance. We found that the viscosity of paint and the thickness of conductive film became the higher but the surface electric resistiance of con-ductive films was the lower than before in accordance with the increase of solid contents in conductive paint and that the surface condition and the surface electric resistiance of conductive films changed highly ac-cording to the drying conditions also. From these results we could get the uniform thickness and the un-iform film resistance and the optimum working property of selectric propertise in CRT when we used the conductive paint with solid contents 28% and viscosity about 13cps.