Thermodynamic calculation and an experimental study of the combustion synthesis of (Mo1−xNbx)Si2 (0 ⩽ x ⩽ 1)

Abstract

The theoretical adiabatic temperature of (Mo1−xNbx)Si2 (0⩽x⩽1) is calculated. The results indicate that the theoretical adiabatic temperature of (Mo1−xNbx)Si2 increases with an increasing Nb content when (Mo1−xNbx)Si2 is of a single-phase structure, but decreases with an increasing Nb content when (Mo1−xNbx)Si2 is of a double-phase structure. All of the temperatures are higher than 1800K, indicating that (Mo1−xNbx)Si2 (0⩽x⩽1) can be prepared by the combustion synthesis method. In this work, (Mo1−xNbx)Si2 (0⩽x⩽1) alloys are successfully synthesized by the combustion synthesis process from elemental powders of Mo, Nb, and Si. The highest combustion temperature and combustion product structure are studied. The results confirm that the variation of the experimental maximum combustion temperature of (Mo1−xNbx)Si2 is consistent with that of the theoretical adiabatic temperature. The combustion products are non-equilibrium species, and a supersaturated solid solution of C11b type (Mo1−xNbx)Si2 forms during combustion synthesis.