This document discusses barium zirconate, including its perovskite structure and applications as an electrolyte and electrode material in intermediate temperature solid oxide fuel cells. It is doped with Y2O3 to create oxygen vacancies. The document covers the advantages of high stability and reduced fabrication problems between 600-800°C, as well as the disadvantage of difficult sintering. It describes the sample preparation process and characterization techniques to analyze phase formation, density, microstructure. Results show single phase formation but low density without ZnO additive, which enables 92-94% density.
4. APPLICATIONS OF BZY
It is used as electrolyte and electrode material in
Intermediate Temperature Solid Oxide Fuel Cell
(IT-SOFC).
5. ADVANTAGES OF BZY
High stability with sufficient proton conductivity in
the temperature range of 600-800o C
Greatly reduces material & fabrication problems
Improves cell reliability during prolonged operations
Stable in CO2 and H2O containing atmosphere
7. SINTERING
Sintering simply means “coalescence of powder at
elevated temperatures.”
The driving force operating during sintering is the
reduction in surface energy.
9. SINTERING STAGES
An interval of geometric change in which pore shape is totally defined
(such as rounding of necks during the initial stage sintering) or an
interval of time during which the pore remains constant in shape while
decreasing in size
10. SAMPLE PREPARATION
Solid-state method
Raw materials: BaCO3 , ZrO2 , Y2O3
Weighing and mixing/grinding
Calcination
Pelletization (uniaxial and cold isostatic pressing)
Solid state sintering
13. RESULTS & DISCUSSIONS
2. PARTICLE MORPHOLOGY & PARTICLE SIZE DISTRIBUTION
Shape not exactly spherical
Paricle size varied from 0.205 µm to 1.405 µm
Average particle size 0.649 µm
14. RESULTS & DISCUSSIONS
3. SINTERING
Dilatometry Temperature Vs Shrinkage
0
Shrimkage (in %)
-2
-4
-6
0 700 1400
O
Temperature (in C)
maximum shrinkage was 5.36 % at 1556o C
15. RESULTS & DISCUSSIONS
3.SINTERING
Densification
Low density
Grain size was 200 – 500 nm
Single phase formation had taken place
16. RESULTS & DISCUSSIONS
4. DENSIFICATION USING ZnO
By using ZnO, 92 – 94 % density was obtained.
17. CONCLUSION
Single phase formation
BZY couldn’t be sintered properly even at 1550o C
ZnO helps in sintering