• Journal of the Korean Ceramic Society
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• v.36 no.10
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• pp.1087-1093
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• 1999

Bioglass which is one of the surface active bionmaterials has a good biocompatibility but a poor mechanical strength, In the present work therefore two types of fluoride-containing bioglasses were coated on an alumina to improve mechanical strength. Crystallization of the coating layer and the hydroxyapatite formation on the bioactive glass coatings in tris-buffer solution were studied. When bioactive glass coated alumina was heat-treated Na2CaSi3O8 crystal was formed on the layer at lower temperature while wollastonite(CaSIO3) was obtained at higher temperature. Hydroxyapatite forming rate on the coating layer with Na2CaSi3O8 crystal was delayed with SiO2 contents in glass composition. However the hydroxyapatite was developed in 20minutes regardless SiO2 contents when the coating layer crystallized into wollastonite. More amount of P3+ ions were leached out of the coating layer with wollastonite than that with Na2CaSi3O8 crystal while Na+ and Ca2+ ions were leached out more easily from the Na2CaSi3O8 crystal containing coating layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.365-366
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• 2009

This study researched into the manufacture of current-limit module of using YBCO coated conductor. Regarding over-current of exceeding the critical current, the quench characteristics were researched according to the stabilizing layer through tendency in resistance, which is generated in conductor, by applying over-current to YBCO coated conductors, which have stabilizing layer. YBCO coated conductors, which were used in experiment, include one kind such as the conductor, which used stainless as the stabilizing layer. The critical current is 70 A. And, the critical temperature is with 90 K. First of all, the quench generation was researched under over-current of exceeding the critical current by using this YBCO coated conductors. The tendency of a rise in the detected voltage according to the applied current was measured. And, the tendency of a rise in resistance through voltage-current curve was measured. As a result, the point of time in thermal quench of conductor, which has stainless as the stabilizing layer, could be confirmed to be fast.

• Journal of the Korean Society for Heat Treatment
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• v.21 no.4
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• pp.183-188
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• 2008

Hot press forming allows geometrically complicated parts to be formed from sheet and the rapid cooling hardens them to extremely high strength. The main purpose of this research is to characterize Al coated layer in Al coated boron steel during hot press forming. For the hot press hardening experiment, test specimens were heated up to $810{\sim}930^{\circ}C$ and held for 3, 6 and 9 minutes, respectively. And then, some specimens were press hardened and others were air-cooled without any pressing for the comparison purpose. Al coated layer shows four distinct micro-structural regions of interest; diffusion zone, Al-Fe zone(I) low-Al zone(LAZ) and Al-Fe zone(II). Band-like LAZ is clearly shown at temperature ranges of $810{\sim}870^{\circ}C$ and sparsely dispersed at temperature higher than 900oC. The micro-cracking behavior in the Al coated layer during forming were also analyzed by bending and deep drawing tests. The strain concentration in softer LAZ is found to be closely related with micro-cracking and exfoliation in coated layer during forming.

• 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.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.245-251
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• 2004

This paper is studied on the effect of TiAlN coated Ball End Mill and MQL(Minimum Quantity Lubrication) cutting condition on cutting characteristic of high hardness steels. KP4 steels[HRC32] and STD11[HRC60] heat treated steels were used as the workpiece and WC-Co ball end mill and single and multi layer TiAlN coated ball end mill were utilized in the cutting tests. MQL device was used to spray botanical oil coolant. Result showed that TiAlN coated ball end mill were increased the cutting length than WC-Co ball end mill in the cutting speed[$245{\sim}320m/min$] about $2.3{\sim}5.7$ times for KP4 steels and about $2.5{\sim}4.3$ times far STD11 heat treated steels. The multi layer TiAlN coated ball end mill is good for KP4 steels than single layer coated.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.1
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• pp.27-33
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• 2016

This study was carried out in order to investigate the effect of binder properties in pre-coating layer on the characteristics of top-coating layer and print mottle of coated paper. Four different latices were used as a binder in pre-coating layer, and coating color prepared with a same formulation was applied for top-coating. The properties and print mottle of coated paper were evaluated. It was found that glass transition temperature (Tg) was the important factor to control the properties of pre- and top-coating layer. PPS roughness of coated paper was decreased and paper gloss was increased with applying binder which has lower Tg. Properties of top-coating layer were affected by the binder used in pre-coating layer. Print mottle of coated paper was improved with using binder which has lower Tg in pre-coating layer. These results indicate that final printability and properties of top-coating layer can be improved with using suitable binder in pre-coating layer.

• Journal of Information Display
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• v.6 no.3
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• pp.26-29
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• 2005

Nanosize cobalt aluminate($CoAl_2O_4$) power was coated as filter layer for us to improve the color purity and contrast performances on the inner face of CRT panel. We simulated color properties by measuring the transmittance and thickness of the coated filter layer. Contrast performance could be improved and color gamut was also changed by the selective light absorption of filter layer at 580${\sim}$605 nm.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.2
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• pp.61-67
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• 2016

This study was carried out in order to investigate the effect of pigment properties in a pre-coating layer on the characteristics of a top-coating layer and the print mottle of the coated paper. Five different pigments were applied for this study as raw materials for the pre-coating layer. The properties and print mottle of the coated paper samples were evaluated according to the coating color formulation. Type of pigments appliied in a pre-coating layer was one of the most important factor to control the properties of pre and top coating layer. Surface properties of pre and top coated paper were improved by blending GCC which had smaller particle size, with clay. Properties of a top-coating layer was affected by the pigment properties used in the pre-coating layer. It was found that print mottle of coated paper can be improved by replacing part of GCC with smaller particle size GCC or clay in pre-coating layer.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.3
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• pp.63-72
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• 1998

This research was intended to evaluate the effect of carboxymethylcellulose(CMC) on the coating structure and surface strength of coated paper prepared with amphoteric latex based coating color. Printability and optical properties of coated papers were compared. The influence of the consolidation behavior of coating color on the coating structure and the surface strength of coated paper was investigated. Compared with the conventional anionic latex, amphoteric latex formed bulkyer, smoother and more porous coating layer, which in turn, restricted binder migration in the coating layers, and facilitated immobilization of coating colors. However, dry pick strength of coated paper was decreased. The addition of CMC to these systems had strongly influenced on. the consolidation behavior and porosity in the dry state, through forming the network structure of coating layers by the interaction with amphoteric latex particles. Thus, printability and optical properties of coated papers were improved. Results indicated that amphoteric latex could be practically applied to the paper coating to improve printability and optical properties of coated papers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.180-181
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• 2006

As a rule, high temperature superconducting coated conductors have multi-layered buffers consisting of seed, diffusion barrier and cap layers. Multi-buffer layer deposition requires longer fabrication time. This is one of main reasons which increases fabrication cost Thus, single buffer layer deposition seems to be important for practical coated conductor process. In this study, a single layered buffer deposition of $CeO_2$ for low cost coated conductors has been tried using thermal evaporation technique 100nm-thick $CeO_2$ layers deposited by thermal evaporation were found to act as a diffusion layer. $0.4{\mu}m$-thick SmBCO superconducting layers were deposited by thermal co-evaporation on the $CeO_2$ buffered Ni-W substrate. Critical current of 118A/$cm^2$ was obtained for the SmBCO coated conductors.