Energetic composites based on aluminium alloy fuels (Al-Ti and Al-Mg) with polyvinylidene fluoride (PVDF): An in-depth study of the fabrication, structure, combustion properties and reaction kinetics
Zhanjun Yang, Hao Liu, Li Mi, Xiaoqian Wang, Li Yang, Zhong‐Xuan Han, Ajay V. Singh, Lin Jiang, Andrei Rotaru
Abstract
This study investigates the combustion characteristics of reactive aluminium alloys in combination with fluoropolymer oxidizers. Aluminium-magnesium (Al-Mg) and aluminium-titanium (Al-Ti) alloys were selected as metallic fuels, while polyvinylidene fluoride (PVDF) was employed as the oxidizer. Composite samples were prepared using two methods: electrostatic spraying (ES) and physical mixing (PM). The ES method yielded samples with a PVDF-coated structure, whereas the PM method produced simple mixtures. The samples and their combustion products were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), combustion experiments, and thermal analysis. The results indicate that compared to the PM samples, the ES-coated samples exhibited more effective dispersion of metallic particles, reduced particle agglomeration, increased combustion heat release temperature, decreased maximum flame area and height, and mitigated or eliminated explosive or micro-explosive phenomena during combustion, thereby achieving stable combustion. Additionally, the ES samples demonstrated a significant reduction in the particle size of condensed-phase products after combustion, alleviated sintering and agglomeration, decreased the formation of metal oxides, and minimized residual metallic fuel, allowing for the full release of combustion heat. Thermal analysis revealed that the coating structure of the ES samples lowered the activation energy for the reaction between the metallic fuel and PVDF, thereby enhancing the chemical reactivity.