Preparation of Aluminum/Boron/Iron-Oxide Nanothermites and Catalytic Activity for Ammonium Perchlorate

Abstract

A novel aluminum/boron/iron-oxide nanothermite with a porous structure was synthesized by sol-gel chemistry combined with an ultrasonic method, in which the aluminum and boron were encapsulated in the nanoferric oxide's skeleton with an average particle size of 50 nm. The catalytic activity of aluminum/boron/iron-oxide nanothermites for ammonium perchlorate decomposition was studied by thermogravimetry/differential scanning calorimetry. Compared with the thermal decomposition of pure ammonium perchlorate, 7 wt % aluminum/ boron/iron-oxide nanothermites decreased the decomposition temperature of ammonium perchlorate by 69°C and increased its apparent decomposition heat by 382.3 J∕g. The higher catalyst addition favors further decomposition of ammonium perchlorate. Through the investigation of nano-iron oxide, nanoaluminum, and micrometer-boron for thermal decomposition of ammonium perchlorate, the nano-iron-oxide particles play the leading role in aluminum/boron/iron-oxide nanothermites for thermal decomposition of ammonium perchlorate and the catalytic activity order is nano-iron oxide > nanoaluminum > micrometer-boron. In addition, the obtained aluminum/boron/iron-oxide nanothermites have higher catalytic activity than the simple mixed sample, which is attributed to the large specific surface area and the nanoporous structure.

Production of the Spherical Nano-Al/AP Composites by Drowning-Out/Agglomeration and Their Solid-Reaction Kinetics

“…For example, the solid propellants containing nano-Al particles have been known to increase significantly the burning rate and lower the ignition time compared with those containing micron-Al particles . Nano-Al particles also have shown various changes in decomposition behavior of ammonium perchlorate (AP) − and to have catalytic effects on the high-temperature decomposition (HTD) of AP . On the contrary, addition of nano-Al also improves the thermal stability of AP in the low-temperature decomposition (LTD) by an increase in the activation energy .…”