Thermochemical Evaluation of Combustion Synthesis of Al₂O₃/B₄C Composite

The equilibrium phase and adiabatic temperature for combustion synthesis of Al₂O₃/B₄C employing Al, B₂O₃ and C as starting materials is analyzed by both conventional and CALPHAD method. The adiabatic temperature calculed by CALPHAD method is significantly lower than that obtained by conventional method. The CALPHAD calculation also reveals that the equilibrium phases presented at the adiabatic temperature are different to the desired composites. The adiabatic temperature in this system can be lowered by introducing Al₂O₃ as diluents. The maximum amount of Al₂O₃ that can be added to the system while maintain a self-sustaining combusion mode is 1.3 mol.