Synergistic Enhancement of Combustion in AlB ₂ @ <i>x</i> CuO Energetic Composites via CuO-Induced Surface Microexplosions and Kinetics

Aluminum boride (AlB₂), despite its high calorific value, faces combustion challenges due to surface oxide layers that obstruct oxygen diffusion, resulting in ignition difficulties and incomplete combustion. To address these limitations, an AlB₂@<i>x</i>CuO energetic composite was synthesized via an alcohol-thermal method, and its combustion mechanism and combustion performance were studied. The surface microexplosions reaction within the composite induces temperature gradient effects, which enhance combustion performance and energy release efficiency. When combined with polytetrafluoroethylene (PTFE) as the oxidizer at equivalent stoichiometric ratios, the AlB₂@<i>x</i>CuO-based composite exhibited a 1347 J/g enhancement in calorific value, a 67.3% reduction in ignition delay, the maximum flame area increased by 73%, and a 239 °C elevation in maximum flame temperature relative to boron-containing systems. Kinetic triplet analysis indicates that the mechanism function for the AlB₂@<i>x</i>CuO-based composite is <i>f</i>(α) = 3(1 - α)[-ln(1 - α)]^2/3, with an activation energy of 143.9 kJ/mol and a logarithmic pre-exponential factor (ln <i>A</i>) of 9.99. The reaction mechanism is consistent with a three-dimensional model of random nucleation and growth.