Nanosized TiO 2-Al 2O 3 composite particles were prepared by gas-phase oxidation of TiCl 4 and AlCl 3 in an aerosol reactor. XPS, ICP, TEM, and XRD measurement were used to characterize the chemical composition, morphology, size and crystal structure of the particles. The effect of processing parameters on the characteristics of composite particles was studied. The results showed that the enhancement of nitrogen flow rate into the reactor tail benefited particle size control. The TiO 2 size increased with increasing reaction temperature and residence time. The crystal structure of titania and alumina in composite particles was affected by the AlCl 3 and TiCl 4 feed ratio. Aluminum titanate was formed at 1.73 s residence time, 1400 ℃ reaction temperature, and 2.80 AlCl 3/TiCl 4 feed ratio.
