Léo Courty

Metal powders have both a high specific energy and a high energy density, which explains their widespread use in energetic materials (propellants, explosives and pyrotechnics). Pyrotechnic compositions are used extensively for both civilian and military applications. However, the combustion of pyrotechnics remains challenging to understand or predict due to the diversity of the components and the wide range of parameters that affect their results. Therefore, ongoing research efforts worldwide aim to investigate the combustion mechanisms of pyrotechnic compositions to improve their performance. In this review, studies on the ignition and combustion mechanisms of four metal powders (Al, Mg, Fe and B) are discussed. Moreover, their use as fuel in pyrotechnic systems is reported, as well as the combustion performance and energy release of the pyrotechnic mixtures. Additionally, some mixtures composed of fluorinated oxidizers and Al, Mg and B are also presented. Thermal analysis methods such as DSC and TG are used to obtain the thermal behavior of the pyrotechnic compositions. Furthermore, parameters such as particle size and the equivalence ratio that affect the performance of pyrotechnic mixtures and those that remain little studied are reported in this review.

Designed to increase safety of people and property during their different stages of life (storage, transportation, handling), low-vulnerability ammunitions (LOVA) can lead to ignition issues during their use. Ignition and combustion characteristics of two LOVA RDX-based gun propellants are experimentally investigated in this paper. The ignition is performed by a laser diode, and combustion is studied in a closed-volume reactor for different initial pressures (10–70 bar) and laser powers (1.39 to 10.13 W). The present study especially focuses on the influence of atmosphere nature: new results under synthetic air are compared to results previously obtained under argon and nitrogen. Air appears to have a different effect on combustion properties following the nature of the propellant. For P1, composed of RDX and HTPB, the highest overpressures and propagation rates are obtained under air. On the contrary, similar performances have been encountered under air and argon for the RDX/NC propellant P2. Ignition delays and probabilities, as for them, seem to be more sensitive to laser power than to atmosphere nature.