A promising strategy to obtain high energy output and combustion properties by self-activation of nano-Al

Aluminum based energetic nanomaterials attract significant attention for various applications owing to their ultrahigh energy density. The main obstacle in the application of nano-Al based energetic materials is the slow combustion reaction kinetics and reduced energy output resulting from the inert Al2O3 shell. In this paper, an efficient surface self-activation strategy is proposed to significantly improve the combustion performance and energy output of nano-Al based energetic materials. A porous AlF3 shell is formed on the surface of the nano-Al particle by an etching reaction between perfluorododecanoic acid and the Al2O3 dense layer. The porous AlF3 shell provides a new reaction channel for the reaction of Al and the oxidizer, thus significantly improving the energy output and combustion reaction kinetics. The energy output and combustion reaction speed of polytetrafluoroethylene (PTFE)/nano-Al coated with C-11 F23COOH are 6304 J/g and 670 m/s, which are 3.0 and 2.6 times higher than those of PTFE/nano-Al, respectively. The mechanism of the self-activating process is proposed to explain the enhanced combustion reaction kinetics and energy output of the nano-Al based energetic materials. The proposed surface self-activation strategy for nano-Al particles can efficiently to enhance the reactivity and energy output and promote the development of the nano-Al based energetic materials. (C) 2019 The Combustion Institute. Published by Elsevier Inc. All rights reserved.