The Production of Some Ultrafine Particles by Gas Phase Reactions in Aerosol Reactors

Abstract

This paper summarizes the authors' recent studies on properties of TiO₂ and nickel powders produced by gas phase reactions in aerosol reactors.
The weight-average diameter and polymorphism of TiO₂ particles at temperatures lower than 1200ºC were virtually unchanged 5-cm downstream from the nozzle mouth, and the effects of the residence time of gas and the reaction temperature were not dominant. However, the mean diameter of nickel powders produced by the hydrogenation of NiCl₂ at 1380ºC was close to the theory assuming instantaneous fusion of coagulated particles. The fraction of rutile was maximum at ca.1000ºC. These results imply the importance of the fusion rate of particles and the heterogeneous deposition rate from the gas phase.