Kinetic analysis of thermite reactions in Al-MoO₃ nanocomposites

Reactions in energetic Al-MoO₃ nanocomposites prepared by arrested reactive milling were investigated by scanning calorimetry and heated filament ignition experiments. The calorimetry data were processed to obtain kinetic parameters describing the reaction between Al and MoO₃. The reaction was treated as a combination of four subreactions, which were described by a combination of a diffusion-controlled reaction model and first-order reactions. The activation energies determined in this study allowed the comparison to reference values for the decomposition of MoO₃ and the diffusion of oxygen through an Al₂O₃ product layer. The kinetic model was extrapolated to high heating rates in the 10 ³-10⁶ K/s range and compared to ignition data. It was concluded that ignition of Al-MoO₃ nanocomposites prepared by arrested reactive milling is primarily controlled by oxygen diffusion in Al ₂O₃.