Abstract
Monodispersed, spherical fine mullite powders were prepared by hydrolysis of Al-Si alkoxide in alcohol/dipolar aprotic solvent. The addition of dipolar aprotic solvent to Al-Si alkoxide/alcohol solutions caused precipitation of Al-Si double alkoxide emulsion. Acetonitrile was most efficient of all dipolar aprotic solvent for the formation of monodispersed fine mullite powders. Monodispersed fine mullite powders were obtained when the volume ratio of octanol/acetonitrile was 3:2. Synthesis factors such as reagent concentration, volume ratio of solvent and reaction temperature influenced the formation of monodispersed fine mullite powders. The Al2O3/SiO2 ratio of as-prepared powders determined by ICP analysis was about 3:2. Powder X-ray diffraction showed that as-prepared powders were amorphous and crystallized to mullite at 1000°C. The spherical morphology was retained after the crystallization.
