Gas-phase particle size distributions and lead loss during spray pyrolysis of (Bi,Pb)--Sr--Ca--Cu--O
- Department of Chemical Engineering, Center for Micro-Engineered Ceramics, University of New Mexico, Albuquerque, New Mexico 87131-6041 (United States)
- VTT Aerosol Technology Group, Technical Research Center of Finland (VTT), P.O. Box 1401, FIN-02044 VTT (Finland)
- Chemical Technology, Technical Research Center of Finland (VTT), P. O. Box 1401, FIN-02044 BYY (Finland)
Gas-phase particle size distributions and lead loss were measured during formation of (Bi,Pb)--Sr--Ca--Cu--O and pure PbO particles by spray pyrolysis at different temperatures. A differential mobility analyzer (DMA) in conjunction with a condensation particle counter (CPC) was used to monitor the gas-phase particle size distributions, and a Berner-type low-pressure impactor was used to obtain mass size distributions and a Berner-type low-pressure impactor was used to obtain mass size distributions and size-classified samples for chemical analysis. For (Bi,Pb)--Sr--Ca--Cu--O, as the processing temperature was raised from 200 to 700 {degree}C, the number average particle size decreased due to metal nitrate decomposition, intraparticle reactions forming mixed-metal oxides and particle densification. The geometric number mean particle diameter was 0.12 {mu}m at 200 {degree}C and reduced to 0.08 and 0.07 {mu}m, respectively, at 700 and 900 {degree}C. When the reactor temperature was raised from 700 and 800 {degree}C to 900 {degree}C, a large number ({similar_to}10{sup 7} no./cm{sup 3}) of new ultrafine particles were formed from PbO vapor released from the particles and the reactor walls. Particles made at temperatures up to 700 {degree}C maintained their initial stoichiometry over the whole range of particle size monitored, however; those made at 800 {degree}C and above were heavily depleted in lead in the size range 0.5--5.0 {mu}m. The evaporative losses of lead oxide from (Bi,Pb)--Sr--Ca--Cu--O particles were compared with the losses from PbO particles to gain insight into the pathways involved in lead loss and the role of intraparticle processes in controlling it.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 69921
- Journal Information:
- Journal of Materials Research, Vol. 10, Issue 7; Other Information: PBD: Jul 1995
- Country of Publication:
- United States
- Language:
- English
Similar Records
Lead-rich phases in partially processed Ag/Bi-2223 composite conductors
Preparation and characterization of superconducting (Bi,Pb) sub 2 Sr sub 2 Ca sub 2 Cu sub 3 oxides with T sub c above 110 K by coprecipitation in triethylamine media