• Progress in Superconductivity and Cryogenics
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• v.8 no.4
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• pp.12-14
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• 2006

YBCO coated conductors have been fabricated by the reel-to-reel processing using TFA-MOD method. In this work, the fluorine-free Y & Cu precursor solution was synthesized to shorten the calcining time by reducing the evolution of HF gas, thus the meter-long YBCO precursor films can be made within few hours by the continuous slot-die coating & calcination step using the F-free Y & Cu precursor solution. The annealing step was followed to make the YBCO films by the reel-to-reel method with the vertical gas flow system onto the moving tape. To increase the growth rate of the YBCO films by enhancing the removal of HF gas, the low total pressure was adopted in the annealing processing. And the water partial pressure and the oxygen partial pressure were varied to optimize the growth conditions of the MOD-YBCO films on the buffered metal tape. FE-SEM and XRD were used to investigate the surface morphologies and the texture of the meter-long YBCO films. The end-to-end critical current $(I_c)$ of 63A/cm-width and the critical current density $(J_c)$of $0.9MA/cm^2$ with the thickness of $0.7{\mu}m$ were obtained in the 0.42m long coated conductor.

• Progress in Superconductivity and Cryogenics
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• v.9 no.1
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• pp.1-4
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• 2007

The total Fluorine content in the precursor solution for MOD processing of YBCO coated conductors can be significantly reduced by synthesizing precursor solution with F-free Y & Cu precursor and Barium trifluoroacetate(TFA). It was shown that crack-free and uniform precursor films were formed after calcinations in humidified oxygen atmosphere. Less than 2 hours are required to finish the calcinations process and XRD measurement shows that $BaF_2,\;CuO,\;Y_2O_3$ are major constituent of calcined precursor films. Film thickness after calcinations was improved to be 2.8um by applying slot-die coating method. In particular, addition of Samarium shows critical current of $I_c=273A/cm-w(J_c=3.8MA/cm^2)$. It is shown that uniform and fast processing route to YBCO coated conductor with high Ic can be provided by employing F-free Y & Cu precursor solution in MOD process.

• Progress in Superconductivity and Cryogenics
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• v.9 no.4
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• pp.16-18
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• 2007

We report the results of MOD-processed YBCO coated conductors on the IBAD-MgO template. The precursor solution was coated on the $CeO_2-buffered$ IBAD-MgO template using a slot-die coating method, calcined at a temperature of $550^{\circ}C$, and fired at high temperatures for 2.5 h in a reduced oxygen atmosphere. The $J_C$ value of YBCO coated conductors was found to be very sensitive to the microstructure, and thus higher $J_C$ value could be achieved when the in-plane texture was higher and the difference in $T_{C,zero}$. was negligible. Optimally processed YBCO coated conductor exhibited $J_C$ value of $0.75MA/cm^2$ at 77 K in self-field, which might be due to somewhat depressed $T_{C,zero}$ of 87.3 K caused by possible $Sm^{3+}$ substitution on the $Ba^{2+}$ site.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.2
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• pp.178-183
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• 2022

For enhancing the flame-retardant properties of wallpapers, we developed an organic-inorganic hybrid solution with ZrSiO₄ as a functional ceramic powder, coated on non-woven fabric using dip coating, spray coating, and slot-die coating methods. Their flame retardant properties were characterized by a 45° combustion tester, which is manufactured according to the flame-retardant performance standard (KOFEIS 1001 and KS F 2819). In organic-inorganic hybrid solution, with increasing the concentration of acid-catalyst (acetic acid), the precipitation of ZrSiO₄ powders increased, and the flame retardant properties decreased. The highest flame retardant result was obtained for the solution adding 5 wt% acetic acid. The optimization of the coating method and coating number resulted in the most excellent flame-retardant properties being obtained for the non-woven fabric coated for 5 or 7 times by dip coating method, and their flame-retardant properties corresponded to class 2 flame-retardant performance of wallpapers.

• Progress in Superconductivity and Cryogenics
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• v.9 no.2
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• pp.23-26
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• 2007

The influence of water partial pressure in Metal-organic Deposition (MOD) method was investigated on the texture and the morphology of $YBa_2Cu_3O_{7-x}$ (YBCO) films grown on the buffered metal tapes. The water partial pressure was varied from 4.2% up to 10.0% with the other process variables, such as annealing temperature and oxygen partial pressure, kept constant. In this work, the fluorine-free Y & Cu precursor solution added with Sm was synthesized and coated by the continuous slot-die coating & calcination step. The next annealing step of the YBCO films was done by the reel-to-reel method with the gas flowed vertically down. From the x-ray diffraction analysis, the un-reacted phase like $BaF_2$ peak was found at the water partial pressure of 4.2%, but $BaF_2$ peak intensity is much reduced as the water partial pressure is increased. However, the higher water partial pressure of about 10% in this experiment leads to the poor crystallinity of YBCO films. The morphologies of the YBCO films were not different from each other when the water partial pressure was varied in this work. The maximum critical current density of 3.8MA/$cm^2$ was obtained at the water partial pressure of 6.2% with the annealing temperature of 780$^{\circ}C$ and oxygen partial pressure of 500ppm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.14-20
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• 2018

Electric vehicles are environmentally friendly because they emit no exhaust gas, unlike gasoline automobiles. However, since they are driven by the electric power from batteries, the distance they can travel based on a single charge depends on their energy density. Therefore, the lithium-ion battery having a high energy density is a good candidate for the batteries of electric vehicles. Since the electrode is an essential component that governs their efficiency, the electrode manufacturing process plays a vital role in the entire production process of lithium-ion batteries. In particular, the coating process is a critical step in the manufacturing of the electrode, which has a significant influence on its performance. In this paper, we propose an innovative process for improving the efficiency and productivity of the coating process in electrode manufacturing and describe the equipment design method and development results. Specifically, we propose a design procedure and development method in order to improve the core plate coating quality by 25%, using a technology capable of reducing the assembly margin due to its high output/high capacity and improving the product capacity quality and assembly process yield. Using this method, the battery life of the lithium-ion battery cell was improved. Compared with the existing coating process, the target loading level is maintained and dispersed to maintain the anode capacity (${\pm}0.4{\rightarrow}{\pm}0.3mg/cm^2r$ reduction).