|About this Abstract
||Materials Science & Technology 2011
||MS&T'11 Poster Session
||212 Tailoring the Relative Si3N4 and SiC Contents in Si3N4/SiC Nanopowders through Carbothermic Reduction and Nitridation of Silica Fume
||Jyothi Suri, Leon Shaw
|On-Site Speaker (Planned)
The present study demonstrates the synthesis of nano-Si3N4/SiC composite powders from silica fume, for the first time. The processing approach to convert the waste silica fume to advanced nanocomposites is based on the integrated mechanical and thermal activation (IMTA) process. The nano-Si3N4/SiC powders synthesized have particle sizes as small as 15-30 nm. It has been shown that the carbothermic reduction and nitridation temperature as well as the graphite concentration in the starting SiO2+C mixture are the important parameters to obtain Si3N4 and SiC nanopowders and control their crystal sizes. The synthesis conditions to tailor the relative contents of Si3N4 and SiC (changing from as high as 37 wt.% to as low as 3.1 wt.% SiC) in the final powder mixture have been investigated, and the mechanisms responsible for the observed relationship between processing conditions and the characteristics of the final powder have been identified.