Thermodynamic predictions for the manufacture of Ti_2AlC MAX-phase ceramic by combustion synthesis

摘要

This paper presents an analysis of the SHS reaction for the manufacture of Ti_2AlC MAX phase materials using self-propagating high-temperature synthesis (SHS). Enthalpy-temperature calculations are presented for the reaction 2Ti + (1 +γ)A1 + C ->Ti_2AlC + yAl. The analysis and data presented allows the determination of the adiabatic combustion temperature as a function of a variety of conditions including (i) reactant pre-heating to increase the combustion temperature or (ii) the addition of excess aluminium as a diluent to reduce the combustion temperature. As excess Al is added as a diluent, there is a decrease in T_(ad) but it offers the potential to control the exothermicity of the SHS process and to form metal-ceramic composites. The range of criteria used for the determination of the appropriate combustion condition for SHS, such as T_(ad) ≥1800 K and -ΔH_r~(298 K)/C_p~(298 K) > 2000 K, are shown to be applicable for Ti_2AlC MAX phase ceramics. The data presented is of use to those considering the manufacture of novel MAX phase ceramics by SHS.