| Effects of the Sintering Atmosphere and Ni Content on the Liquid-phase Sintering of $TiB_2$-Ni |
| Suk-Joong L. Kang , Jin-Chul Baung1, Yeon-Gyu Park2, Eul-Son Kang3, Yong-Kee Baek3, Sug-Woo Jung |
Materials Interface Laboratory, Department of Materials Science and Engineering, Korea Advanced Institute for Science and Technology
1Now, with Samsung Electro-Mechanics
2Now, with Sam-Young Technology Research Institute, Korea Insulators Industrial Co.
3Agency for Defense Development |
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| ABSTRACT |
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The effects of the sintering atmosphere and Ni content on t도 densification of TiB$_2$-Ni have been investigated. TiB$_2$powder compacts containing 10, 20, and 30 wt% Ni were liquid-phase sintered at 1500-1$700^{circ}C$ in vacuum or in flowing Ar. The densification was enhanced as Ni content increased. For a given Ni content, the densification was faster in compacts in compacts with larger grain size. These densification behaviors agree well with the prediction of the recently developed pore-filling theory. For samples containing high Ni contents, 80TiB$_2$-20Ni and 70TiB$_2$-30Ni, the densification was faster in vacuum than in Ar. In particular, 70TiB$_2$-30Ni was fully densified at 1$700^{circ}C$ for 60min in vacuum. The suppressed densification in Ar was due to the entrapped Ar in the isolated pores. On the other hand, for 90TiB$_2$-10Ni, the Ar-sintering resulted in higher densification than did the vacuum-sintering. This result was attributed to the suppression of Ni volatilization by the Ar in the furnace and a retarded isolation of pores due to the limited amount of liquid in the sample. Therefore, vacuum sintering is recommended for the preparation of TiB$_2$-Ni with a high Ni content while Ar sintering is recommended for the preparation of TiB$_2$-Ni with a low Ni content. |
| Key words:
$TiB_2$-Ni cermet, Liquid phase sintering, Sintering atmosphere, Densification, Densification mechanism |
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