Precise fabrication and superior combustion properties of n-B pomegranate microspheres based on a new dissolution-dispersion-coating method

To enhance the reactivity and combustion efficacy of boron powders, a new dissolution-dispersion-coating (DDC) method of fabricating nano-boron (n-B) pomegranate microspheres were developed. Metal nanoparticles were uniformly encapsulated within n-B microspheres, which varied in size from 2 to 500 μm. The spheroidization mechanism of microsphere structure was investigated. Subsequently, the ignition and combustion performance of the prepared pomegranate microspheres were evaluated by combustion tests at 0.2 and 0.5 MPa, respectively. The results demonstrated that the n-B microspheres of F5 (75 wt% n-B@17 wt% NC@8 wt% n-Ti) exhibited superior performances, achieving the largest flame area, minimal ignition delay time and combustion time. The combustion thermal value and combustion residue analysis indicated that the content of available boron in the F5 microspheres exceeded 72.6 % and the combustion was complete. This study provides a novel approach to enhance the ignition and combustion efficiency of n-B powders.