Flight combustion of the agglomerate powders containing energy (APCE) in making new hollow multiphase ceramic microspheres by self-reactive quenching technology

Al–TiO2–Fe–Fe2O3–MnO2, as the main reaction system, was selected to prepare the agglomerate powders containing energy (APCE) on 50–90 μm by balling, drying, carbonating, grinding and sieving. Self-reactive quenching technology, which is integrated with flame spraying, self-propagating high-temperature synthesis (SHS) and rapid solidification, was used to spray and melt the APCE. Flight combustion of the APCE was analyzed by high-speed photography, water quenching, collisions and Gibbs free energy graph, and surface morphologies of quenching products were characterized by SEM. The results show that the APCE goes through three stages, which mean heat storage (0–80 mm, 66–72 ms), heat releasing (80–240 mm, 73–83 ms) and after combustion (240–400 mm, 84–99 ms), to form hollow ceramic droplets which decisively affect the quality of hollow multiphase ceramic microspheres. Collisions and burst may be the main reasons to produce flame retrogression and affect the particle size distribution of hollow multiphase ceramic microspheres simultaneously.