Preparation of nanocrystalline SnO2 thin film coated Al2O3 ultrafine particles by fluidized chemical vapor deposition

Fluidized chemical vapor deposition (FCVD) technology was developed for coating SnO₂ thin film on Al₂O₃ ultrafine particles. TEM and HREM analysis found that SnO₂ films with different structures were deposited by controlling the coating temperature, reactant concentration, etc. Nanocrystalline SnO₂ film was coated at 573.15 K by gas phase reaction of SnCl₄ with H₂O. EPMA and EDS studies indicated that the distribution of SnO₂ inner and outer of the agglomerates was uniform. Nucleation and film deposition were coexisted mechanism during the FCVD coating process. The fraction of SnO₂ in the composite particles increased with increasing coating temperature, SnCl₄ concentration, and coating time. The mass fraction of SnO₂ in the composite particles increased strongly with the ratio of P_H2O and P_SnCl4 at low mole ratio of H₂O with SnCl₄, but increased little under the conditions of excess H₂O with respect to SnCl₄.