Study on the Mechanism of Preparation of Hollow Microspheres with Electromagnetic Wave Absorption Ability by Liquid Jet

This paper studied the mechanism of preparation of ferrite hollow microspheres by liquid jet. The ferrite hollow microspheres were prepared by the sol-gel. During the preparation, the oxygen-acetylene flame was used as reaction conditions, and the water quenching method was used to obtain reaction products. The jetting process of flame thermal injection gun can be divided into several stages, such as gel atomization, liquid droplets decomposition reaction in heating of oxygen-acetylene flame, hot melt droplets contraction under the quenching water, and formation of jet reaction products. After the reaction products being collected, dried and heat treated, the electromagnetic (EM) wave absorption ability of La mole content at 0, 0.05, 0.1, 0.15 and 0.2 were analyzed, the results revealed that the EM wave absorption ability of ferrite hollow microbeads was enhanced after the addition of rare earth element La, and the best effect was achieved when the amount of rare earth element La was 0.15. High speed photography was used to analyze the reaction process of small droplets of sol-gel in various stages of flight. These photos vividly showed that the small droplets of sol-gel expanded, split and collided during jetting.