Micro-explosions caused by the reaction of nano-sized aluminium and polyvinylidene fluoride to promote the micron-sized aluminium combustion and inhibit its agglomeration

Abstract

Micron-aluminium (μAl) powder is difficult to ignition and prone to agglomeration during combustion, leading to the reduced combustion efficiency. To solve the issues, Al powders with different particle sizes were modified by polyvinylidene fluoride (PVDF) and studied using thermogravimetry–differential scanning calorimetry (TG-DSC), laser ignition experiments, and advanced characterization techniques. These methods revealed that violent micro-explosions caused by the interaction of PVDF and nano-Al (nAl) can effectively promote the combustion of μAl and inhibit its agglomeration. The mixing of nAl_PVDF and μAl_PVDF accelerates the oxidation reaction, increases heat release, and improves combustion performance, particularly for the nAl_PVDF/μAl_PVDF (1:4) sample, which exhibits the largest flame area, the highest flame expansion speed and flame temperature, and the shortest ignition delay and combustion time. The synergistic effect of PVDF and nAl enhances the fragmentation of μAl during combustion, resulting in smaller condensed combustion products. These results provide insights from both thermal analysis and combustion experiments, laying a foundation for improving the ignition and combustion efficiency of μAl.