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Reactive infiltration of silicon melt through microporous amorphous carbon preforms

1999; Springer Science+Business Media; Volume: 30; Issue: 5 Linguagem: Inglês

10.1007/s11663-999-0099-1

1543-1916

Prasert Sangsuwan, S. N. Tewari, Jorge E. Gatica, Mrityunjay Singh, R. Dickerson,

Advanced ceramic materials synthesis

The kinetics of unidirectional capillary infiltration of silicon melt into microporous carbon preforms has been investigated as a function of the pore morphology and melt temperature. The infiltrated specimens showed alternating bands of dark and bright regions, which corresponded to the unreacted free carbon and free silicon regions, respectively. The decrease in the infiltration front velocity for increasing infiltration distances is in qualitative agreement with the closed-form solution of capillarity-driven fluid flow through constant-cross-section cylindrical pores. However, drastic changes in the thermal response and infiltration front morphologies were observed for minute differences in the preform’s microstructure. This suggests the need for a dynamic percolation model that would account for the exothermic nature of the silicon-carbon chemical reaction and the associated pore-closing phenomenon.