• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.317-319
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• 2008

Photo-alignment layer which contains cinnamate is difficult to generate pretilt angle of liquid crystals. In order to enhance pretilt angle, blending poly (amic acid) between containing fluorine poly (amic acid) and 1,2,3,4-cyclobutanetetracaroxylic dianhydride (CBDA) / 3,5-diaminobenzyl alcohol (DBA) were used. For photoreaction, cinnamate was conjugated by interfacial reaction with blending polyimide.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.6
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• pp.683-689
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• 2006

Statement of problem. Interfacial toughness is important in the mechanical property of layered dental ceramics such as core-veneered all-ceramic dental materials. The interfaces between adjacent layers must be strongly bonded to prevent delamination, however the weak interface makes delamination by the growth of lateral cracks along the interface. Purpose. The purpose of this study was to determine the effect of the reaction layer on the interfacial fracture toughness of the core/veneer structure according to the five different divesting. Materials and methods. Thirty five heat-pressed Lithia-based ceramic core bars (IPS Empress 2), $20mm{\times}3mm{\times}2mm$ were made following the five different surface divesting conditions. G1 was no dissolution or sandblasting of the interaction layer. G2 and G3 were dissolved layer with 0.2% HF in an ultrasonic unit for 15min and 30 min. G4 and G5 were dissolved layer for 15min and 30min and then same sandblasting for 60s each. We veneered bilayered ceramic bars, $20mm{\times}2.8mm{\times}3.8mm$(2mm core and 1.8mm veneer), according to the manufacturer's instruction. After polishing the specimens through $1{\mu}m$ alumina, we induced five cracks for each of five groups within the veneer close to interface under an applied indenter load of 19.6N with a Vickers microhardness indenter. Results. The results from Vickers hardness were the percentage of delamination G1:55%, G2:50%, G3:35%, G4:0% and G5:0%. SEM examination showed that the mean thickness of the reaction layer were G1 $93.5{\pm}20.6{\mu}m$, G2 $69.9{\pm}14.3{\mu}m$, G3 $59.2{\pm}20.2{\mu}m$, G4 $0.61{\pm}1.44{\mu}m$ G5 $0{\pm}0{\mu}m$. The mean interfacial delamination crack lengths were G1 $131{\pm}54.5{\mu}m$, G2 $85.2{\pm}51.3{\mu}m$, and G3 $94.9{\pm}81.8{\mu}m$. One-way ANOVA showed that there was no statistically significant difference in interfacial crack length among G1, G2 and G3(p> 0.05). Conclusion. The investment reaction layer played important role at the interfacial toughness of body ceramic bonded to Lithia-based ceramic.

• Journal of the Korean Ceramic Society
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• v.44 no.12
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• pp.710-714
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• 2007

LSGM$(La_{0.8}Sr_{0.2}Ga_{0.8}Mg_{0.2}O_{3-{\delta}})$ is the very promising electrolyte material for lower-temperature operation of SOFCs, especially when realized in anode-supported cells. But it is notorious for reacting with other cell components and resulting in the highly resistive reaction phases detrimental to cell performance. LDC$(La_{0.4}Ce_{0.6}O_{1.8})$, which is known to keep the interfacial stability between LSGM electrolyte and anode, was adopted in the anode-supported cell, and its effect on the interfacial reactivity and electrochemical performance of the cell was investigated. No severe interfacial reaction and corresponding resistive secondary phase was found in the cell with LDC buffer layer, and this is due to its ability to sustain the La chemical potential in LSGM. The cell exhibited the open circuit voltage of 0.64V, the maximum power density of 223 $mW/cm^2$, and the ohmic resistance of $0.17{\Omega}cm^2$ at $700^{\circ}C$. These values were much improved compared with those from the cell without any buffer layer, which implies that formation of the resistive reaction phases in LSGM and then deterioration of the cell performance is resulted mainly from the La diffusion from LSGM electrolyte to anode.

• Journal of the Korean Society for Heat Treatment
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• v.16 no.5
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• pp.260-266
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• 2003

In order to study the interfacial reaction between Nb thin sheet and Fe-C-(Si) alloy with different Chemical compositions, they were cast-bonded. The growth of carbide layer formed at the interface after isothermal heat treatment at 1173K, 1223K, 1273K and 1323K for various times was investigated. The carbide formed at the interface was NbC and the thickness of NbC layer was increased linearly in proportional to the heat treating time. Therefore, It was found that the growth of NbC layer was controlled by the interfacial reaction. The growth rate constant of NbC layer was slightly increased with increase of carbon content when the silicon content is similar in the cast irons. However, as silicon content increases with no great difference in carbon content, the growth of NbC layer was greatly retarded. The calculated activation energy for the growth of NbC layer was varied in the range of 447.4~549.3 kJ/moI with the compositions of cast irons.

• Applied Microscopy
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• v.26 no.1
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• pp.95-104
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• 1996

A comprehensive methodology to characterize the interfacial reaction products of $SiC_p/2024$ Al composites is introduced on the basis of the experimental results obtained using XRD, SEM and TEM. XRD performed on the electrochemically extracted $SiC_p$ and bulk $SiC_p/2024$ Al composite have shown that the interfacial reaction products consist of $Al_{4}C_3$ having hexagonal crystallographic structure, pure eutectic Si having diamond cubic crystallographic structure, and $CuAl_2$, having tetragonal crystalloraphic structure, respectively. According to the images observed by SEM, $Al_{4}C_3$, which has been reported to have needle shape, has a hexagonal platelet-shape and eutectic Si is found to have a dendritic shape. In addition eutectic $CuAl_2$, was observed to form near interface and/or along the grain boundaries. In order to confirm the results obtained by XRD, the primitive cell volume and reciprocal lattice height of such interfacial reaction products were calculated using the data obtained from convergent beam electron diffraction (CBED) patterns, and then compared with theoretical values.

• Transactions of Materials Processing
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• v.7 no.5
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• pp.481-488
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• 1998

The active metal brazing was applied to bond Alumina and Ni-Cr steel by Ag-Cu-Zr-Sn alloy and the interfacial microstructure and reaction mechanism were investigated. Polycrystalline monoclinic $ZrO_2$ with a very fine grain of 100-150 nm formed at the alumina grain boundary contacted with Zr segregation layer at the interface. The $ZrO_2$ layer containing the inclusions and cracks were developed at the boundary of inclusion/$ZrO_2$ due to the difference in specific volume. The development of $ZrO_2$ at the interface was successfully explained by the preferential penetration of $ZrO_2$ at the interface was successfully explained by the preferential penetration of Zr atoms a higher concentration of oxygen and a high diffusion rate of Al ions into molten brazing alloy.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1311-1312
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• 2006

This paper describes the ohmic contact formation between a TiW film as a contact material deposied by RF magnetron sputter and polycrystalline 3C-SiC films deposied on thermally grown Si wafers. The specific contact resistance (${\rho}_c$) of the TiW contact was measured by using 4he C-TLM. The contact phase and interfacial reaction between TiW and 3C-SiC at high-temperature were also analyzed by XRD and SEM. All of the samples didn't show cracks of the TiW film and any interfacial reaction after annealing. Especially, when the sample was annealed at $800^{\circ}$ for 30min., the lowest contact resistivity of $2.90{\times}10^{-5}{\Omega}{\cdot}cm^2$ of was obtained due to the improved interfacial adhesion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.406-407
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• 2006

This paper describes the ohmic contact formation between a TiW film as a contact material deposied by RF magnetron sputter and polycrystalline 3C-SiC films deposied on thermally grown Si wafers. The specific contact resistance (${\rho}_c$) of the TiW contact was measured by using the C-TLM. The contact phase and interfacial reaction between TiW and 3C-SiC at high-temperature were also analyzed by XRD and SEM. All of the samples didn't show cracks of the TiW film and any interfacial reaction after annealing. Especially, when the sample was annealed at $800^{\circ}$ for 30min., the lowest contact resistivity of $2.90{\times}10^{-5}{\Omega}cm^2$ was obtained due to the improved interfacial adhesion.

• Journal of Power System Engineering
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• v.5 no.4
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• pp.74-81
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• 2001

The infiltration behavior of molten Al-alloy, microstructures, hardness, and the interfacial reactions of $SiC_p/Al$ composites fabricated by the pressureless infiltration technique were investigated. It was made clear that both the weight fraction of SiC reinforcement and additive Mg content considerably influenced on the infiltration behavior of the molten Al-alloy matrix. Complete infiltration of molten Al-alloy achieved under the conditions that weight fraction of SiC content is more than 30wt%, and additive Mg content is more than 9wt%. Interfacial region of Al-alloy matrix and SiC reinforcement phase, $Mg_2Si$ was formed by the reaction between Mg and SiC. Another reaction product AlN was also formed by the reaction between Al-alloy matrix and gas atmosphere nitrogen.

• Journal of Korea Foundry Society
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• v.17 no.4
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• pp.371-378
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• 1997

The study for direct synthesis of TaC carbide which was a reaction product of tantalum and carbon in the cast iron was performed. Cast iron which has hypo-eutectic composition was cast bonded in the metal mold with tantalum thin sheet of thickness of $100{\mu}m$. The contents of carbon and silicon of cast iron matrix was controlled to have constant carbon equivalent of 3.6. The chracteristics of microstructure and the formation mechanism of TaC carbide in the interfacial reaction layer in the cast iron/tantalum thin sheet heat treated isothermally at $950^{\circ}C$ for various time were examined. TaC carbide reaction layer was grown to the dendritic morphology in the cast iron/tantalum thin sheet interface by the isothermal heat treatment. The composition of TaC carbide was 48.5 at.% $Ti{\sim}48.6$ at.% C-2.8 at.% Fe. The hardness of reaction layer was MHV $1100{\sim}1200$. The thickness of reaction layer linearly increased with increasing the total content of carbon in the cast iron matrix and isothermal heat treating time. The growth constant for TaC reaction layer was proportional to the log[C] of the matrix. The formation mechanism of TaC reaction layer at the interface of cast iron/tantalum thin sheet was proved to be the interfacial reaction.