A novel simple method to stably synthesize Ti_3AlC_2 powder with high purity

摘要

In this work, a novel simple method is presented to synthesize highly pure Ti_3AlC_2 powder by heating 2TiC/Ti/Al (molar ratio) powder system between 1300 ℃ and 1400 ℃ for 15-30 min in flowing argon atmosphere. 2TiC/Ti/Al is selected as the raw material because of its much lower exothermal quantity than elemental 3Ti/Al/2C powder system in reacting process. The purity of Ti_3AlC_2 is not sensitive to the final temperature, soaking time or raw material scale. Its content is maintained around 97 wt.%, even though the scale of mixed raw materials vary from 5 g to 1000 g. The synthesized samples can be easily ground into powders with a mean particle size of 4.9 μm. Synthesis mechanism shows that both Ti_2AlC and Ti_3AlC_2 will generate from the reaction among TiC, Ti and Al below 1200℃. Above 1300℃, Ti_2AlC will continue to react with TiC and generate Ti_3AlC_2. The formation of Al liquid phase above 660 ℃ is considered as a promoting factor in the reacting process.