• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.159.1-159
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• 2002

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1995.11a
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• pp.30-30
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• 1995

• Proceedings of the Materials Research Society of Korea Conference
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• 2002.11a
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• pp.25-25
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• 2002

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.88.1-88.1
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• 2015

In recent printed electronics technology, Photo-Sintering, a technique for sintering materials using a light source, has attracted attention as an alternative to time-consuming high-temperature thermal processes. The key principle of this technique is the selective heating of a strongly absorbent thin film, while preventing the heating of the transparent substrate by the light source. Many recent studies have used a flash lamp as the light source, and investigated the material-dependent effect of the width or intensity of the pulsed light. However, the flash lamp for sintering is not suitable for industry yet, because of needing too high power to sinter for a large scale. In energy-saving and large-scale sintering, LED technologies would be very useful in the near future. In this work, we investigated a sintering process for silver nanoparticles using UV-LED array. Silver nanoparticles in ink were inkjet-printed on a $1{\times}1cm$ area of a PET film and photo-sintered by 365 nm UV-LED module. A sheet resistance value as low as $72.6m{\Omega}/sq$ (2.3 - 4.5 times that of bulk silver) was obtained from the UV-LED sintering at 300 mW/cm2 for 50 min.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.10
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• pp.906-910
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• 2008

$(K_{0.5}Na_{0.5})NbO_3$ (NKN) ceramics doped with $Li_{2}CO_3$ as sintering aids were manufactured in order to develop the low temperature sintering ceramics for piezoelectric device. The sintering aids were proved to lower the sintering temperature of doped NKN ceramics due to the effect of $Na_{2}CO_{3}-Li_{2}CO_3$ liquid phase. All the specimens showed the orthorhombic phase without secondary phase. And also, the piezoelectric properties of specimens were improved with increasing $Li_{2}CO_3$ contents. At sintering temperature of $930^{\circ}C$, the density, electromechanical coupling factor (kp), mechanical quality factor (Qm) and dielectric constant(${\epsilon}_{\gamma}$), piezoelectric constant of 0.3 wt.% $Li_{2}CO_3$ added specimen showed the optimum values of $4.255 g/cm^3$, 0.37, 234, 309, 136 pC/N, respectively.

• Journal of Powder Materials
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• v.27 no.5
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• pp.365-372
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• 2020

Predicting the quality of materials after they are subjected to plasma sintering is a challenging task because of the non-linear relationships between the process variables and mechanical properties. Furthermore, the variables governing the sintering process affect the microstructure and the mechanical properties of the final product. Therefore, an artificial neural network modeling was carried out to correlate the parameters of the spark plasma sintering process with the densification and hardness values of Ti-6Al-4V alloys dispersed with nano-sized TiN particles. The relative density (%), effective density (g/㎤), and hardness (HV) were estimated as functions of sintering temperature (℃), time (min), and composition (change in % TiN). A total of 20 datasets were collected from the open literature to develop the model. The high-level accuracy in model predictions (>80%) discloses the complex relationships among the sintering process variables, product quality, and mechanical performance. Further, the effect of sintering temperature, time, and TiN percentage on the density and hardness values were quantitatively estimated with the help of the developed model.

• Electrical & Electronic Materials
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• v.7 no.4
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• pp.306-311
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• 1994

In this study, the influence of the powder sintering, the 2nd sinteiing and the grinding time on the Superconducting properties in the Bi(Pb)SiCaCuO Superconductor has been studied. From the analysis of SEM and XRD patterns, it was known that the sample prepared by the process of powder sintering has a porous microstructure with the critical temperature(Tc) below 77K, while the sample prepared by the 2nd sintering has a highly oriented microstructure with the Tc above 100K. The Critical Current Density(Jc) of the sample prepared by the 2nd sintering was better than the sample prepared by the process of powder sinteiing, but it's Jc, was low in practical use. Also, the effect of grinding time from 0[min] to 120[min] was investigated. As the grinding time is increased, the samples degraded from high-Tc phase to low-Tc phase and nonsuperconducting phases.

• Journal of Powder Materials
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• v.27 no.4
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• pp.293-299
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• 2020

W₂C is synthesized through a reaction-sintering process from an ultrafine-W and WC powder mixture using spark plasma sintering (SPS). The effect of various parameters, such as W:WC molar ratio, sintering temperature, and sintering time, on the synthesis behavior of W₂C is investigated through X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) analysis of the microstructure, and final sintered density. Further, the etching properties of a W₂C specimen are analyzed. A W₂C sintered specimen with a particle size of 2.0 ㎛ and a relative density over 98% could be obtained from a W-WC powder mixture with 55 mol%, after SPS at 1700℃ for 20 min under a pressure of 50 MPa. The sample etching rate is similar to that of SiC. Based on X-ray photoelectron spectroscopy (XPS) analysis, it is confirmed that fluorocarbon-based layers such as C-F and C-F2 with lower etch rates are also formed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.1
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• pp.1-5
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• 2019

The physical properties of ceramic materials including oxides are greatly influenced by the material density. Therefore, various efforts have been made to increase the material density. One of the most popular strategies is to use sintering additives in sintering materials. The conventional sintering additive was a spherical powder having a three-dimensional structure. In this study, sintering additive with 2-dimensional (2D) layer structure was used to increase the sintering density of cerium oxide and its effect was confirmed. In this study, 1 nm-thick $TiO_x$ and $MnO_x$ nanosheets were used as sintering additives.

• Korean Journal of Metals and Materials
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• v.49 no.9
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• pp.678-685
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• 2011

The aim of this study was to determine the effect of applied pressure and sintering temperature on the microstructure and mechanical properties for spark plasma sintering (SPS) from commercial pure titanium (CP-Ti) powders. Spark plasma sintering is a relatively new sintering technique in powder metallurgy which is capable of sintering metal and ceramic powers quickly to full density at a fairly low temperature due to its unique features. SPS of -200 mesh or -400 mesh CP-Ti powders was carried out in an $Ar+H_2$ mixed gas flowing atmosphere between $650^{\circ}C$ and $750^{\circ}C$ under 10 to 80 MPa pressure. When SPS was carried out at relatively low temperatures ($650^{\circ}C$ to $750^{\circ}C$), the high (>60 MPa) pressure had a marked effect on densification and grain growth suppression. The full density of titanium was achieved at temperatures and pressures above $700^{\circ}C$ and 60 MPa by spark plasma sintering. The crystalline phase and microstructure of titanium sintered up to $700^{\circ}C$ consisted of ${\alpha}$-Ti and equiaxed grains. Vickers hardness ranging from 293 to 362 Hv and strength ranging from 304 to 410 MPa were achieved for spark plasma sintered titanium.