Effect of Mechanical Alloying on the Preparation of SiO_2-Al Composite Powders

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 SiO2-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,SiO2-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.