The Influence of Aerosol Droplet Number Density on Aerosol Droplet Coalescence in Powders Synthesized by the Spray Pyrolysis Method

摘要

The influence of aerosol droplet number density on aerosol droplet coalescence in BaTiO_3, ZnO and Bi_1.8Pb_0.2Sr_2Ca_2Cu_3O_x powders derived by the spray pyrolysis method was investigated. The initial aerosol droplet size and aerosol droplet number density were expressed in terms of the aerosol generator type, aerosol flow rate, carrier gas flow rate and properties of the precursor solution. It was shown that aerosol droplet coalescence was established in the case of ZnO powder synthesized by ultrasonic atomization for the initial number of droplets 2. 137x10~8 cm~3 when the carrier as well as the aerosol flow rate were 80 dm~3/h and 0.09 dm~3/h, respectively. This caused particle coarsening and certainly affected the resulting particle morphology. In the case of BaTiO_3 and Bi_1.8Pb_0.2Sr_2Ca_2Cu_3O_x powders synthesized by twin-fluid and ultrasonic atomization there was no evidence of droplet coalescence for the initial number of droplets of 10~8 cm~3.