Preparation of Hollow SiC Ceramic Microspheres With Drop-tower Technique

SiC ceramic microspheres were fabricated by drop-tower technique at low temperature using polycarbosilane (PCS) as raw material. The as-prepared microspheres were characterized by TG, IR, SEM and XRD. The reaction mechanism of organic polymer and the effects of process parameters (composition of furnace atmosphere and temperature) were investigated. The results show that ethanol as a blowing agent has a high blowing efficiency, and the content of helium gas in the furnace atmosphere ranging rising to 50%-80% can increase the heating-up rate of gel particles in heat-absorbing stage. The high sphericity morphology is obtained at 500-600 ℃. Moreover, the SEM spectra indicate that irradiation can increase the surface finish quality and evenness of hollow SiC ceramic microspheres.