Reacting CMAS with Yttrium Disilicate Environmental...
Transcript of Reacting CMAS with Yttrium Disilicate Environmental...
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Department of Materials
Reacting CMAS with Yttrium Disilicate Environmental Barrier Coating
Mentor: William Summers
w Professor Frank Zok
Melissa Morales w
Chemical Engineering w
UC Santa Barbara
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Silicon carbide ceramic matrix composites (SiC CMCs) likely to replace nickel alloys
Boeing 727-100 aircraft
http://www.pw.utc.com/JT8D_EnginePratt & Whitney JT8D Engine
http://www.pw.utc.com/JT8D_Engine
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1973-1982
1986-1996
2000
Firing Temperature (oC)
900 1000 1100 1200 1300 1400 1500 160040
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50
55
60
65
Combined CycleEfficiency (%)
3.2% / 100oC
Raising firing temperature improves engine efficiency
Adapted from GE Power Systems GER-41943
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Images courtesy GE Aviation
Silicon carbide ceramic matrix composites (SiC CMCs) likely to replace nickel alloys
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1975 1985 1995 2005 2015 2025
Super alloys
SiC/SiCCMC
Year
Temperature (oC)
Adapted from Richards, Wadley 2014
Silicon carbide ceramic matrix composites (SiC CMCs) likely to replace nickel alloys
1965
700
900
1100
1300
1500
1700
1900
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Without Environmental Barrier Coating
SiC CMC
O2
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Without Environmental Barrier Coating
SiC CMCSiO2
O2
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Without Environmental Barrier Coating
SiC CMCSiO2
H2O
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Without Environmental Barrier Coating
SiC CMCSiO2
H2O Si(OH)4
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Without Environmental Barrier Coating
SiC CMC
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Without Environmental Barrier Coating
SiC CMCSiO2
H2O Si(OH)4
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Without Environmental Barrier Coating
SiC CMCSiO2
H2O Si(OH)4
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Without Environmental Barrier Coating
SiC CMCSiO2
H2O Si(OH)4
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EBC
With Environmental Barrier Coating
SiC CMC14
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EBC
With Environmental Barrier Coating
H2O
SiC CMC15
O2
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EBC
CMAS
With Environmental Barrier Coating
SiO2
• CMAS: Calcium-Magnesium-Alumina-Silicate• Siliceous materials, desert sand to volcanic ash
SiC CMC16
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EBC
CMAS
With Environmental Barrier Coating
apatite
SiC CMCSiO2
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CMAS
(CaO)31%(MgO)9%(FeO1.5)5%(AlO1.5)12%(SiO2)43% at 1400oC – 4 hours
YDS EBC
Apatite
100 μm
Apatite byproduct causes cracks to form in environmental barrier coating layer
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CMAS
YDS EBC
Apatite
100 μm
Apatite byproduct causes cracks to form in environmental barrier coating layer
How can we prevent or mitigate the reaction between the EBC and CMAS?
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0.5 1.0 1.5 2.0
Predicted Equilibria
Mol of Yttrium Disilicate EBC Consumed
0.8
0.6
0.4
0.2
0.0
Calcia to Silica Mol Ratio
(CaO)31%(MgO)9%(FeO1.5)5%(AlO1.5)12%(SiO2)43%
(CaO)20%(MgO)5%(FeO1.5)5% (AlO1.5)10%(SiO2)60%
(CaO)10%(MgO)5%(FeO1.5)5% (AlO1.5)5%(SiO2)70%
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David Poerschke
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Prepare and Grind Powders
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Prepare and Grind Powders
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Prepare and Grind Powders
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Press Powders Into Pellets
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React Powders in Furnace (1300oC)
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Prepare for Microscope
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3000X Test 1 C31%S43% & 0.333 mol YDS
Pore
CMAS
Apatite
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3000X Test 5 C31%S43% & 2.0 mol YDS
Anorthite
Apatite
CMAS
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Residual Yttrium Disilicate
3000X Test 5 C31%S43% & 2.0 mol YDS
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3000X Test 3 C10%S70% & 0.333 mol YDS
CMAS
Anorthite
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3000X Test 4 C31%S43% & 1.0 mol YDS
CMAS
Anorthite
Apatite
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CaO MgO FeO1.5 AlO1.5 SiO2 YO1.5
Expected 8% 4% 4% 8% 65% 12%
Measured 5% 2% 3% 37% 45% 9%
Expected- Al
8% 4% 4% 70% 14%
Measured- Al
8% 3% 4% 71% 14%
Test 3: Overall vs. Expected
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CaO MgO FeO1.5 AlO1.5 SiO2 YO1.5
Expected 8% 4% 4% 8% 65% 12%
Measured 5% 2% 3% 37% 45% 9%
Expected- Al
8% 4% 4% 70% 14%
Measured- Al
8% 3% 4% 71% 14%
Test 3: Overall vs. Expected
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CaO MgO FeO1.5 AlO1.5 SiO2 YO1.5
Expected 8% 4% 4% 8% 65% 12%
Measured 5% 2% 3% 37% 45% 9%
Expected- Al
8% 4% 4% 70% 14%
Measured- Al
8% 3% 4% 71% 14%
Test 3: Overall vs. Expected
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Anorthite
Future Recession Experiments
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Future Recession Experiments
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Future Recession Experiments
200 μm
200 μm
200 μm
(CaO)31%[…](SiO2)43% at 1400oC - 4 hours
(CaO)20%[…](SiO2)60% at 1400oC - 4 hours
(CaO)10%[…](SiO2)70% at 1400oC - 4 hours 37
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AcknowledgementsWilliam Summers
David Poerschke
Frank W. Zok
Stephanie Mendes
Kelly Ibsen
Chris Siefe
Megan Wakefield