Investigation of the influence of B@Fe composite fuel on the thermal decomposition and ignition combustion performance of ammonium perchlorate (AP)

Abstract

Four sets of B@Fe composite fuels with varying Fe elemental composition were synthesized with a chemical liquid-phase reduction method, and their impact on the thermal decomposition and ignition combustion performance of ammonium perchlorate (AP) was studied. Characterization revealed that the B@Fe composite fuel particles exhibited sizes ranging from approximately 1 to 5 μm, with a uniform distribution of the Fe elements on the surfaces of amorphous B particles. The incorporation of B@Fe composite fuel led to a reduction of around 10 °C in the low-temperature decomposition peak temperature of AP. As the Fe elemental content in the B@Fe composite fuel increased, it exhibited a trend of initially increasing and then declining peak temperature reduction. Both B/AP and B@Fe/AP composite fuels exhibited characteristic non-homogeneous combustion processes, with flames primarily composed of typical green characteristic flames derived from BO₂ and yellow non-gaseous metallic particle flames internally. Increasing Fe elemental content within the B@Fe composite fuel resulted in enhanced dispersity of non-gaseous metallic particles, improved combustion completeness of B, and reduced aggregation of B during combustion. The combustion products of the B@Fe/AP composite fuel formed agglomerates consisting of flake-shaped particles with sizes ranging from 50 to 100 μm. With escalating iron content, the flake-shaped particle structure progressively transitioned into a lamellar form, decreasing in size, while the inter-particle binding became less compact. The condensed combustion products predominantly comprised B, BN, BFe₂, and FeB₂, with the uniformity of the Fe elemental distribution within the condensed combustion products demonstrating enhancement with increasing Fe elemental content.