Rapid synthesis of high-purity Al4SiC4 powder by microwave hybrid heating

Abstract

Abstract Al4SiC4 powder was successfully synthesised at a temperature 150 °C lower than before: the use of a microwave hybrid heating method required only 3 % of the heating time compared to conventional methods. The effects of composition and processing parameters, such as temperature and dwell time on the formation process of Al4SiC4 were investigated. The results indicated that with the excess Al from 0 to 5 at.% in the composition, the amount of Al4SiC4 phase in the samples processed at 1 200 °C increased together with the decreasing amount of Al4C3 phase. Further increases in the content of Al above 5 at.% resulted in the decrease of the Al4SiC4 phase content. For a fixed composition of Al : SiC : C of 4.05 : 1 : 3, Al4SiC4 formed as a major phase together with the decrease of SiC, C, and Al4C3 phases at temperatures varying from 1 000 °C to 1 500 °C for 6 min. When the dwell time was extended to 15 min at 1 500 °C, a high-purity Al4SiC4 phase with a tiny amount of impurities could be synthesised. The as-obtained powder was mainly composed of hexagonal plate-shaped particles with a mean diameter of approximately 1 μm.