Thermite materials feature very exothermic solid-state redox reactions. However the energy release rates are limited by the slow mass transport in thermite mixtures. In this work ALD technique was utilized to form core-shell structured nano-thermite materials by depositing ZnO or SnO2 films on the aluminum nano-powder. Under saturated surface reaction conditions, the film growth rates on the aluminum nano-powder were 0.15 nm/cycle for ZnO and 0.035 nm/cycle for SnO2, comparable to those measured on flat substrates. The thickness of the oxidizer layer could be controlled by adjusting the number of ALD cycles. The compositions and structures of the nano composites were characterized by XPS, SEM and HRTEM. Laser ignition experiments showed that combustion of the ALD nano-composites were much faster and more violent than the bare aluminum powder and the aluminum-SnO2 powder mixture. Combustion rates increased dramatically as the oxidizer/fuel ratio approaches the stoichiometric ratio of the corresponding thermite reaction.

Core-shell structured nanothermite materials synthesized by atomic layer deposition

245th National Meeting (2013)

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