Monodispersed hollow ceramic microspheres fabricated based on preceramic polymers and pulse-controlled coaxial injection

Hollow ceramic microspheres (HCMs) have widespread applications in aerospace and electronic areas owing to their multiple merits such as low density, low thermal conductivity, oxidation, and high-temperature resistance. In this work, monodispersed HCMs were fabricated based on preceramic polymers and the pulse-controlled coaxial injection approach. The size and shell morphology of hollow ceramic spheres can be flexibly tailored by adjusting the diameters of coaxial needles, and the composition and flow rates of inner and outer liquids. As-obtained HCMs were comprised of ultrafine nanocrystals of ZrO 2 , SiO 2 , ZrC, and SiC, which can enhance the interfacial polarization effect. Through optimization of microstructure and composition, the electromagnetic shielding performance of HCMs reached up to 45 dB in the frequency range of 12–18 GHz. This work demonstrates a facile and general method for the fabrication of monodispersed HCMs.