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YSZ Pellets for Solid Oxide Fuel Cells
Final Presentation
Presented by: Lazo TrkuljaAdvisor: Professor Elliott Slamovich
Graduate Student Advisor: Jeff Reding
Outline
• Overview of SOFC’s• Showing how research fits into big picture
• YSZ pellet processes• Ball milling, pressing, bisquing
• Obtaining Data for comparisons• Profilometer and peak edge removal
measurements
• Results and Conclusions
Solid Oxide Fuel Cells
• How do SOFC’s work?
)(2)(2
1 22 sOegO eOHgHsO 2)()( 22
2
Anode Reaction Cathode Reaction
Picture obtained from http://www.iit.edu/~smart/garrear/fuelcells.htm.
YSZ Pellet Processing
• Combining components to form a slurry• YSZ powder, binder (Duramax HA-8), dispersant
(Duramax D-3005), DI water
• Ball Milling• Followed by drying of slurry in oven
• Pellet Pressing• Application of stearic acid to die• Approx. 68 MPa for approx. 1 min.
• Bisquing• Early stage of sintering
.
Profilometer
• Average Surface Roughness ( )
• Used to compare pellets
aR
1 2 3 ................ na
y y y yR
n
Roughness DataTotal Average Roughness for 2% Binder Composition
0
500
1000
1500
2000
2500
0 1 2 3 4 5
Pellet number
To
tal P
elle
t A
ve
rag
e R
ou
gh
ne
ss
(n
m)
Data
Total Average Roughness for 4% Binder Composition
0
500
1000
1500
2000
2500
0 1 2 3 4 5
Pellet number
To
tal P
elle
t A
ve
rag
e R
ou
gh
ne
ss
(n
m)
HistogramHistogram for Pellet #2 and 4% Binder
Set
0
1
2
3
4
5
6
100 500 900 1300 1700
Average Surface Roughness (nm)
Fre
qu
en
cy
DataTotal Average Roughness for the 10% Binder Set
0
500
1000
1500
2000
2500
3000
0 1 2 3 4 5
Pellet Number
To
tal A
ve
rag
e R
ou
gh
ne
ss
(n
m)
DataTotal Average Roughness for 2%, 4%, and 10% Binder
Sets
0
500
1000
1500
0 2 4 6 8 10 12
Binder Composition
Ro
ug
hn
ess
(n
m)
Edge Removal Data
Total Average Edge Removal Peak for 2% and 4% Binder Sets
0
200
400
600
800
1000
1200
1400
0 1 2 3 4 5
Pellet Number
Ave
rag
e E
dg
e R
em
ova
l L
en
gth
(m
icro
ns)
2% Binder Set
4% Binder Set
Edge Removal DataTotal Number of Significant Edge Removals for 2% and 4% Binder
Sets
9
5
8
6
1920
19
10
0
5
10
15
20
25
1 2 3 4
Pellet Number
Nu
mb
er o
f E
dg
e R
emo
vals
2% Binder Set
4% Binder Set
Conclusions
• Definitive pellet set cannot be reached• Trade-off between 2% and 4% sets• User determines pellet priorities
• Pellet pressing is key in pellet quality• Uniform application of stearic acid on die• Careful handling of pellet after ejection