The Effect of the Sintering Additives on the Fabrication and Thermal Conductivity of Porous Sintered RBSN |
Young-Jo Park, Hai-Doo Kim |
Powder Materials Research Division, Korea Institute of Materials Science |
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ABSTRACT |
The nitriding and post-sintering behavior of silicon powder compact containing sintering additives of 2.3 wt% and 7 wt% were investigated in this study. Regardless of the liquid phase content, elongated large grains of a typical morphology evolved in the post-sintered specimens. Phase analysis revealed a complete phase transformation into ${beta}-Si_3N_4$ in both porous systems. Oxynitride second phases (mellilite) precipitated in the latter, while those were free in the former containing less amount of liquid phase. The post-sintering condition that yielded a favorable microstructure for a filter application was achieved when the specimens were soaked at $1800^{circ}C$ for 2 h. It was found that the thermal conductivity of porous $Si_3N_4$ ceramics is dominated by the porosity more than this factor is influenced by the addition of $Al_2O_3$. |
Key words:
RBSN, SRBSN, DPF, Porous, Thermal conductivity |
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