The synthesis of high purity Ti3AlC2 MAX phase via molten salt method

[Display omitted] •Ti3AlC2 MAX phase with purity of 99.0% was synthesized by molten salt method.•Powder is prepared in a vacuum quartz tube without inert gas protection.•Mechanical activation reduces reaction temperature and improves product purity.•Two mechanisms have been proposed. Many methods have been used to synthesize the Ti3AlC2 MAX phase, but obtaining high-purity (>99.0 %) Ti3AlC2 is still a challenge. In this work, nano/submicro-sized Ti3AlC2 powder was prepared using Ti/Al/C elemental powders by the molten salt method in a vacuum quartz tube system. The effects of reaction temperature and dwell time, mechanical activation, the ratio of flux to reactants, and the ratio of Al on the synthesis of Ti3AlC2 were systematically investigated. The results show that Ti3AlC2 powder with a high purity of up to 99.0 % was prepared using ball milled 3Ti/1.1Al/2C mixture as the reaction material, and NaCl-KCl as the molten salt at 1150 °C for 2 h. The reaction mechanisms of Ti3AlC2 in molten salt have been discussed.