An approach to the induced reaction mechanism of the combustion of the nano-Al/PVDF composite particles

Highly reactive aluminum-fluorine composites with novel structures have attracted much attention in the past decades. However, there is not a specific mechanism to explain the combustion-supporting or inducing effect of F-polymer on aluminum powders. Herein, we present a systematic study of the induced reaction mechanism and propose a new elaboration. Two types of Nano-aluminum/Poly(vinylidene fluoride) (n-Al/PVDF) composites are fabricated via electrospray and mechanical mixing method, respectively. The electrospray sample excites a Pre-Ignition Reaction (PIR) between fluorine and the Al 2 O 3 shell at a low temperature, and simultaneously the specific surface area, surface element state and alumina shell structure of aluminum powders change to some extent. However, the surface structure of the physical mixture does not change significantly in the same temperature range. On this basis, we studied the relationship between the change of surface structure and the enhanced combustion performance of aluminum in electrospray sample. The results show that the combustion-supporting effect of PVDF on aluminum powder should be attributed to the corrosion of the alumina shell and the loose structure of the PIR product. The induction mechanism of Al-F reaction to Al-O reaction is that the PIR changes the structure and element state of aluminum powders surface. That is, the increase of specific surface area and the division of alumina shell significantly promote the Al-O reaction. • PIR changes the chemical state and microstructure of the aluminum powder surface. • The AIMD study clarified the initial process of the PIR reaction. • PVDF participates in PIR and main reaction according to a mass ratio close to 40/60.