Study on New Direct Titration Process of Ceramic Microspheres

The gelcasting SnO₂ slurry was prepared with SnO₂ powders with the average size of 0.1-0.5 μm as raw material. The slurry was directly titrated on the rotating metal based super hydrophobic surface by titration syringe, so that SnO₂ droplets could be solidified into balls on the super hydrophobic rotating metal base surface under different conditions. The effects of droplet size, forming time and solid content on microsphere molding were studied. The results showed that the sphericity of SnO₂ ceramic microsphere formed by direct titration was ideal, which was higher than that by conventional titration method, and the diameter of ceramic microspheres was 0.1-0.5 mm. The sphericity of the microspheres increased with the increase of solid content, and decreased with the increase of droplet size and the increase of curing time. When the droplet size was adjusted to 0.05 mm and the optimized SnO₂ powder with a solid was by gel casting process in 30 min at 60℃, the SnO₂ ceramic microspheres with the highest sphericity up to 99.5% could be obtained. The surface microstructure of the microsphere was uniform and the sphere shape could be maitained after sintering.