• Korean Journal of Materials Research
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• v.12 no.10
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• pp.825-830
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• 2002

The growth rate of solid grains in TiC-XC-2vol% and TiC-XC-30vo1% Ni cermets, where X=Zr, W or Mo, was fitted to an equation of the form $d^3$-$do^3$=Kt. The grain growth behavior during liquid phase sintering at 1673K decreased markedly with addition of $Mo_2$C or WC and increased with addition of ZrC. The contiguity ratio was greater in the alloys with smaller growth rate constant and decreased with increasing Ni content in the $TiC-Mo_2$C-Ni cermet. The grain growth mechanism could be explained by the effect of contiguous grain boundaries in restricting the overall grain growth.

• Journal of the Korean Ceramic Society
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• v.40 no.9
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• pp.832-836
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• 2003

Multi-layer ceramic composites were prepared by tape casting followed by hot pressing using silicon nitride layer with silicon nitride whiskers, silicon nitride layer with silicon carbide particles and boron nitride-alumina layer. The whiskers were aligned during the casting. As the whisker content of the silicon nitride layer was increased up to 10 wt％, the flexural strength of the multi-layer composite was increased. However, further increase of the whisker content in the layer resulted in a rapid decrease of the strength of the composite. The results suggest that the strength of multi-layer ceramic composite showing non-catastrophic failure behavior can be significantly improved by incorporating the aligned whiskers in the layers.

• Journal of the Korean institute of surface engineering
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• v.47 no.5
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• pp.252-256
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• 2014

The TiAlCrSiN film was deposited on the WC-20%TiC-10%Co carbide, and its oxidation behavior was examined at $700-1000^{\circ}C$. It displayed relatively good oxidation resistance owing to the formation of $TiO_2$, $Al_2O_3$, $Cr_2O_3$, and $SiO_2$ up to $900^{\circ}C$. However, at $1000^{\circ}C$, the fast oxidation rate and partial oxidation of WC in the substrate led to the formation of the thick, fragile oxide scale.

• Progress in Superconductivity and Cryogenics
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• v.15 no.1
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• pp.6-10
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• 2013

We investigate the electrical and thermal transport properties of a sesquicarbide superconductor $La_2C_3$, including electrical resistivity, thermoelectric power, and thermal conductivity. The electrical resistivity exhibits a typical metallic character with a saturation behavior at high temperatures. The thermoelectric power shows a metallic behavior with pronounced phonon-drag effect, comparable with pure metals. The broad peak of the thermal conductivity is observed in the superconducting state, which is rapidly suppressed by magnetic fields. These observations suggest that the electron-phonon scattering is significant in $La_2C_3$, which is relevant with the relatively high-$T_c$ in $La_2C_3$ through strong electron-phonon coupling with low frequency phonon modes.

• Journal of the Korean Ceramic Society
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• v.39 no.7
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• pp.622-627
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• 2002

Multi-layer composites consisting of silicon nitride, silicon nitride-silicon carbide and boron nitride-alumina layers were prepared fly stacking the corresponding ceramic tapes. The composites demonstrated self-diagnostic capability and non-catastrophic failure behavior. The composites consisting of many thin layers exhibited high strength and stepwise increase of the electrical resistance during the flexure test. The strength of the composite with too thick silicon nitride layers was low and the electrical resistance was abruptly increased to the detection limit of the digital multi-meter during the test. An extensive crack branching was observed in the weak (BN + Al$_2$O$_3$)layer.

• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1075-1079
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• 2001

The R-curve for in situ-toughened SiC-30 wt% TiC composites was estimated by the indentation-strength method and compared to that of monolithic SiC with toughened microstructure. Both materials exhibited rising R-curve behavior. The SiC-TiC composites, however, displayed better damage tolerance and higher resistance to crack growth. Total volume fractions of SiC key grains, which take part in toughening mechanisms such as crack bridging and crack deflection, were 0.607 for monolithic SiC ceramics and 0.614 for SiC-TiC composites. From the microstructural characterization and the residual stress calculation, it was inferred that this superior performance of SiC-TiC composites can be attributed to stress-induced microcracking at heterophase (SiC/TiC) boundaries and some contribution from carck deflection by TiC grains.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.69.1-69
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• 2003

• Proceedings of the KWS Conference
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• 1998.05a
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• pp.249-250
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• 1998

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1996.11a
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• pp.10-10
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• 1996

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.23.1-23
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• 2002