Effect of B, Fe, Ti, Cu nanopowders on the laser ignition of Al-based high-energy materials

The use of metal powder as a fuel in the high-energy materials (HEMs) for the propulsion is the most energy-efficient method to increase the specific impulse and improve the combustion characteristics in the chamber. HEMs typically contain aluminum powders with different particle size distribution. To improve the ignition characteristics of the Al-based HEMs, it is advisable to use nonmetals, metals or their oxides as a catalyst. This paper presents the experimental data on the thermal decomposition and ignition of HEM samples based on ammonium perchlorate, butadiene rubber containing nanopowders (NP) of Alex aluminum, amorphous boron, iron, titanium, and copper. Additives of 2 wt% iron and copper NP in the HEM sample with Alex decrease the ignition delay time by 11-16% when the sample is ignited by a CO2 laser in the range of heat flux density of 60-200 W/cm(2). They also increase the recoil force of the gasification products outflow with the HEM surface by 1.3-1.5 times due to reduced temperatures of the onset and intense decomposition of HEM under heating. The partial replacement of Alex by a 5 wt% boron NP in the HEM sample reduces the ignition delay time by up to 20%. (C) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.