Abstract: The impact of process control agent addition on the extraction rate and the milling time on the powders refinement, mechanical alloying and thermal stability of SiO_2-Al composite powders were studied in this paper. The composite powders after milling were analyzed by laser particle size analyzer, scanning electron microscopy, X-ray diffraction and differential thermal analyzer. The result showed that by 20 h of milling, the extraction rate of composite powders was up to 85% with adding 4% of the process control agent. With the extension of milling time, SiO_2-Al composite powders have been gradually refined, median diameter down to 4.35 μm after 20 h milling, but there is no reaction occurred. The temperature of reaction has been fallen with the extension of milling time.

Key words: SiO_2-Al%mechanical alloying%solid-state reaction