Synthesis of Ti3AlC2 max phase under vacuum, its structural characterization and using for Ti3C2Tx MXene preparation

•MAX phase (Ti3AlC2) with low amount of impurities was prepared at 1300 °C under vacuum.•MAX phase contained carbon vacancies and oxidised states of titanium and aluminum.•MXene (Ti3C2) prepared from MAX phase by etching in LiF/HCl solution.•MXene thin films with specific conductivity of 3000 S/cm were obtained. The MAX phase (Ti3AlC2) was synthesized by sintering Ti, TiC, Al precursors under vacuum. The effect of temperature on the formation of the Ti3AlC2 phase was studied. The MAX phase with a minimum amount of impurities was obtained under vacuum at 1300 °C. The phase composition, structure, and state of the surface of the MAX phase were investigated. It was found that carbon vacancies are formed in the Ti3AlC2 lattice. Oxidized states of Ti, C, and Al elements are present on the surface of Ti3AlC2 crystallites. Despite the presence of structural defects and oxidized surface states of titanium and aluminum, the synthesized MAX phase was suitable for preparing 2D MXene particles (Ti3C2Tx) and highly concentrated stable colloidal solutions (up to 5 g/L) based on them. Thin MXene films, prepared from such Ti3C2Tx colloidal solution, were characterized by a high electrical conductivity of 3000 S/cm.