1. Perovskite and Oxide Synthesis by Spray Pyrolysis Thomas Graule Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH Thomas.graule@empa.ch

2. content principle spray pyrolysis spray pyrolysis test facility at EMPA composition and morphology

3. why spray pyrolysis? demands on ceramic powder fabrication for SOFCs: –controlled composition (including impurity content) –continous production process –controlled and reproducible powder morphology –cost effective production lines spray pyrolysis:  easy control of the composition in a salt solution  suited for continous production  control of composition and morphology of the ceramic particles in one single preparation step  off-gas treatment

4. principle spray pyrolysis salt (nitrate) solution granulationcalcination evaporation precipitation decomposition sintering composition precursor spray pyrolysis morphologycomposition spray dryingheat treatment morphology

5. spray pyrolysis test facility at EMPA

6. typical spray pyrolysis conditions solutions (nitrates):almost saturated solution flow rate:ca. 30 ml/min air pressure rate:2 bar ultra sonic frequency:40 MHz furnace temperature:450 - 500 °C  yields powders of 4 - 6 g/min, 2-3 kg/day (8h)  limitations: –water evaporation –furnace power, flow rate, water content in precursor solution

7. preparation of La x Ca 1-x Fe y Co 1-y O 3 sintered granulate 1100°C 1000°C 800°C

8. morphology of La(Sr)MnO 3 sprayed grains agglomerate size: 20 - 80 microncrystallite size: < 0.5 micron

9. morphology of La(Sr)MnO 3 sprayed and sintered LSM grains prepared by spray pyrolysis agglomerate size: 10-20 (50) microncrystallite size: 2-5 micron

10. summary present experience: –phase pure perovskites have been prepared Examples: (La x Sr 1-x ) y MnO 3, (La x Ca 1-x )(Fe y Co) 1-y O 3 homogenous powder morphology –production rate is up to 3 kg/per day the method is generally applicable to oxide and non oxide ceramics tailoring of powder morphology by spray pyrolysis parameters and powder processing after the preparation process suspensions of YSZ added to the precursor solution can be used