Composite number

Engineering

Boron

Materials science

Heat of combustion

Propellant

Chemical engineering

Thermodynamics

Physics

Organic chemistry

Combustion

Ammonium perchlorate

Composite material

Evaporation

Chemistry

Ignition system

Chemical Engineering Journal

The low energy release efficiency seriously hinders the application of Boron (B) powder as metal fuel in solid propellants. To overcome this issue, a series of B-based spherical composites were produced by encapsulating B-based metastable intermixed composites (MICs) with ammonium perchlorate (AP) by a solvent evaporation-induced self-assembly (EISA) method in this work. A self-developed combustion system containing an ignition pool, indicator light, and high-speed camera to precisely monitor ignition delay and burning times was utilized. The EISA-prepared B/Bi2O3/AP spherical composites showed higher combustion temperature (1435 °C) and shorter ignition delay time (379 ± 25 ms) than the physically mixed sample (1264 °C and 1035 ± 63 ms). The isolated reaction units of spherical B/Bi2O3/AP composite accelerated heat transfer and accumulation and reduced sintering and agglomeration, thus promoting the combustion efficiency of B powder. This study presents a promising strategy by doping and encapsulating process to increase the combustion performance of B-based metal fuel.

Encapsulated boron-based energetic spherical composites with improved reaction efficiency and combustion performance