Synthesis of MAX phases Ti2AlC and V2AlC by carburization of hydrogenated alloys Ti2AlHx and V2AlHx

Abstract

The present study shows that Ti2AlC and V2AlC could be synthesized by carburization of special precursor alloys. The initial Ti and V were hydrogenated, milled, and then mixed with Al particles. The prepared mixtures were annealed under vacuum and the temperature of 1000 °C was sufficient for alloy formation. The produced Ti2AlHx and V2AlHx alloys were brittle, which enabled crushing and mixing with carbon black. The obtained powders were heated under vacuum to nucleate the MAX phases. The annealing at 1100 °C was optimal because at lower and higher values of temperature either the carburization process was not complete or phase decomposition was observed. Additional experiments for synthesis of layered ceramics from the mixtures of TiHx/VHx, Al, and C were characterized with a slower reaction kinetics. The analysis of isothermal oxidation demonstrated smaller exothermic effects for Ti2AlHx compared to TiHx at 200–600 °C, while V2AlHx had lower intensities at 200–400 °C but higher at 500–600 °C with respect to VHx.