Iranian Scientific Association of Energetic Materials

In this research, the effects of the particle size and shape of aluminum powder on the kinetics and thermodynamic properties of HMX thermal decomposition in a PBX formulation were investigated. Nano-structured aluminum powder has flaked shape and thickness of about 20-30 nm. Kinetics and thermodynamic parameters were calculated by both Kissinger and Flynn-Wall-Ozawa (FWO) methods based on differential scanning calorimetry under non-isothermal condition with heating rate of 5, 10, 15 and 20 °C/min. Results compared with the same composition formulated by micronized aluminum powder. Calculations showed that the activation energy of thermal decomposition of HMX decreased 35 kJ/mol by replacement of nano-structured Al powder instead of micronized particle. Furthermore pre-exponential factor, Critical Temperatures for the Thermal Explosion, and 500-day cookoff temperature decreased significantly.