Synthesis of low-cost Ti3AlC2-Ti2AlC dual MAX phase with high-electrical conductivity using economical raw materials and novel compositions

Titanium-aluminum-carbide (Ti3AlC2-Ti2AlC) dual MAX phases produced with mechanical alloying (MA) of raw materials followed by a self-propagating high-temperature synthesis (SHS) approach. The low-cost dual MAX phases have been manufactured from commercial powders of Ti, Al, TiC, and agricultural wastes-based activated carbon (AC). The effects of Ti/Al/C mole ratios and carbon sources with various prices on the surface morphology, microstructure, chemical structure, and electrical conductivity of dual MAX phases have been investigated. All synthesized MAX phases have acceptable surface morphology with hexagonal particles and high purity (78.87-99.26 %). The FESEM, EDS, XRD, and XPS analyses revealed that the AC and TiC are appropriate as carbon sources for the manufacture of Ti3AlC2-Ti2AlC dual and Ti3AlC2 single MAX phases, respectively. Moreover, the purity of the MAX phases can be controlled with Al/C ratios in raw materials composition. The ACproduced Ti3AlC2-Ti2AlC dual MAX phase with 3Ti:1.25Al:2 C displayed the highest electrical conductivity (5.631 x106 S/m), while TiC-produced Ti3AlC2 single MAX phase with 3.25Ti:2.2Al:2 C composition has comparable electrical conductivity (2.203 x106 S/m) and highest purity (99.26 %). This study makes available an advantageous method for low-cost synthesis of high-purity MAX phases. These understandings open up a pathway to improve synthesis protocols for low-cost and high-conductivity MAX phases in the future.