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transcript
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Advanced Thermal Barrier Coatings for Operation in High Hydrogen Content Gas Turbines
Gopal Dwivedi, Vaishak Viswanathan,Yang Tan, Yikai Chen
Prof. Christopher M. Weyant, Prof. Sanjay Sampath
DOE UTSR Meeting, Oct 22nd, Purdue University
Dwivedi et al., JACerS, DOI: 10.1111/jace.13021
Viswanathan et al., JACerS, DOI: 10.1111/jace.13033
Dwivedi et al., JTST, Under Review
Viswanathan et al., JACerS, Under Review
DOE NETL UTSR
Contract #DE-FE0004771
2010-2014
Program Manager: Dr. Briggs while
DOE UTSR Meeting, Oct 2014, Purdue University, IN
2
Single Layer YSZ
2010
4 years 600 hrs
50 +coating conditions
40+ architectures
600+ FCT samples
Adequate erosion
resistance
Significantly higher
durability
CMAS resistance
Mechanisms and
Methodology to
incorporate andy
new composition
Snapshot of accomplishment under UTSR program
Layer-2
Layer-1
Layer-3
1,200 hrs
2014
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Interplay between TBC durability and “manufactured” coating properties
o Ceramic strength/toughness o Ceramic coating compliance
and ceramic chemistry
o Bond coat chemistry, Roughness
o Ceramic coating toughness o Ceramic coating composition
o Coating density o Coating porosity/cracks
o Bond coat roughness
o Coating thickness
o Pore architecture
o Coating thickness
3
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Multilayered architecture to combat multifunctional requirements
Plasma spray is naturally suited for such layered
manufacturing
Erosion, FOD, CMAS/Ash
Low-K material, Porosity,
Lower sintering rate
Remains complaint
Compatibility with Bondcoat
Mostly traditional TBC, High
toughness
Adequate roughness,
oxidation resistant (dense),
environmental effects
Mech
. A
nd
ch
em
ical
co
mp
ati
bil
ity
4
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Multilayered architecture to combat multifunctional requirements
Erosion, FOD, CMAS/Ash
Low-K material, Porosity,
Lower sintering rate
Remains complaint
Compatibility with Bondcoat
Mostly traditional TBC, High
toughness
Adequate roughness,
oxidation resistant (dense),
environmental effects
5
DOE UTSR Meeting, Oct 2014, Purdue University, IN
6 Impact of water vapor on conv. & new TBC materials
No significant difference found at this temperature, and long term
exposures
HVOF bond coats (NiCoCrAlY & NiCoCrAlYHfSi) for ORNL testing
ORNL is investigating the interactions with several different substrate materials
Collaborative partnership with ORNL- Materials selection
Initia
l Results
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Figure 7: This process map relates NiCr (a surrogate for NiCrAlY) particle states, achieved during liquid and gas fuel HVOF (Woka and Diamond Jet) and plasma spray (Triplex) to resultant microstructures and roughness. Significant difference among the TS bond coats exist in terms of microstructure, density and internal oxidation. These differences can dramatically affect performance. It is critical to understand these effects to optimize NiCrAlY bond coats. Maps allow for systematic tailoring of coating properties.
Not all bond coats are the same! Processing plays a role 7
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Processing Effects on HVOF Bond Coats
HVOF process type and spray
conditions significantly affect
deposition stresses and final stress
state of the coaitng.
Jetkote STD JP5000 STD
Jetkote- Reducing JP5000- Reducing
JP5000 chosen due to microstructure and
compressive stress state.
8
Stress State
Evolving Thermal Residual
Str
es
s (
MP
a)
-300
-200
-100
0
100
200
Jetkote STD
Jetkote Reducing
DOE UTSR Meeting, Oct 2014, Purdue University, IN
9
Collaboration with Dr. Bruce Pint and Dr. Allen Haynes at ORNL
XPT: NiCoCrAlY
AMDRY: NiCoCrAlY-HfSi
Reactive element bondocat showed
higher life under all the conditions
Down selection of bond coat material
Pint et al., AMP May 2012
DOE UTSR Meeting, Oct 2014, Purdue University, IN
100 µm
100 µm
Fra
ctu
re in
to
pco
at
Fra
ctu
re in
TG
O
100 µm
100 µm
BC roughness effects may overshadow chemical effects? T
op c
oat
life
(h
ou
rs)
0
100
200
300
400
500
600
700
Commercial CTSR
Furnace
cycle test
24 hrs cycle
0
2
4
6
8
10
12
Ro
ug
hn
ess,
Ra (
mm
) Commercial CTSR
Bondcoat layer
require adequate
roughness for
high TBC life
10
NiCoCrAlYHfSi
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Particle Diameter (m)10 100
Volu
me (
%)
0
4
8
12
16
20
AMDRY 386-2 D50
: 32.31m
AMDRY 386-4 D50
: 62.72mCoarse
Fine Particle size
Two layered architecture
Processing Control
Rough bond coat surface
Strategy
Utilize the Fine particle size for Dense Oxidation Resistant initial layer
Utilize the Coarse particle size to tailor the topography for high surface
roughness
Feedstock
Processing Strategies 11
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Substrate
Layer-1: ~100µm Fine powder (Dense microstructure)
Layer-2: ~50µm Coarse powder (Rough Surface) b
on
d c
oa
t
Two layers bond coat deposition
50µm 50µm 50µm
Densest bottom layer
Poor splat cohesion
Denser bottom layer
Poor splat cohesion and some
cracking
Least dense bottom layer
Good particle melting and splat
cohesion
Deposition Scheme 12
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Rene 80
NiCrAlYHfSi
YSZ
150μm
300μm
Rene 80
NiCrAlYHfSi (Two Layered)
YSZ
150μm
300μm
Rene 80
Commercial
YSZ
150μm
300μm
NiCrAlYHfSi NiCrAlYHfSi
(Two Layered)
Commercial
Similar top coats on 3 different bond coats
FOCUS : Two Layered Bond Coat
0
200
400
600
800
1000
FC
T H
ours
Improved bond coat
roughness
Performance of the Two Layered Bond Coat 13
DOE UTSR Meeting, Oct 2014, Purdue University, IN
14
Teixeira et al., JTST, 9(2), 2000—191
Padture et al., vol. 296,Science, 280,
2002
With extending service hours
TGO Growth: Additional Stress build up at
the interface. (limited control)
Sintering: loss in compliance
=> higher stress build up. Higher driving force
for crack propagation. Process optimization to
design coating with large compliance in as
sprayed condition.
Substrate
Bondcoat
TBC
σ= 0
σ = σi σ = σis
1st cool
down
nth cool
down
σis >> σi
σis ≥ σc :Failure
100µm 100µm
As-deposited TBC Failed (~600 hrs)
Failure
Mechanism
Failure mechanism of TBCs: Occurring at BC-TC interface
Majority of TBC failure occur at the BC-TC
interface. Parameter of interest is Fracture
Toughness.
DOE UTSR Meeting, Oct 2014, Purdue University, IN
15 Is the toughness sensitive to microstructure of TBCs?
Fractured X-section. APS YSZ coating
Splat
Intersplat boundaries
Pores or voids
Lamellar pores
Intrasplat cracks
1 m Some defects present more tortuous
path to a crack than others.
1µm
Splat
detachment
Fracture
through
splats
Interlamellar pore as a
possible crack path
These defects can be controlled via
processing.
Plasma spray can be utilized to produce significantly different microstructures.
Can we manipulate the effective fracture toughness of these structure?
Abradables Layered
structures Segmented
Structures
APS YSZ
50m 50m 50m
Large globular
pores
Layered structure
with thin splats
Vertical crack with
high “local” density
The defect architecture governs
Thermal conductivity and Coating
compliance
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Fracture Toughness: Double Torsion Technique
PrecrackLoad, P Specimen
t
W
Wm
Notch
Max. Load for
fracture
12 mm
39- 40 mm
20
mm
16
4 point bend loading at the notched edge
Pre-cracking @ 0.001 mm/sec
Loading till fracture @ 0.01 mm/sec
21
4
13
StSPK mICIC
PIC - Maximum load at failure
- Poisson’s ratio
S - specimen width
Sm - moment arm
t - specimen thickness
- thickness correction factor
= 1-1.26(t/S)+2.4(t/S)exp(-pS/2t)
Free standing
coating
Advantages:
Does not require crack length monitoring
Can be performed a low thickness specimen (~600µm).
DOE UTSR Meeting, Oct 2014, Purdue University, IN
50µm
Coarse powder cut
50µm
Ensemble powder cut
Particle Diameter (microns) 3 30 10 100
Volu
me (
%)
0
5
10
15
20
25
30 D50: Mean particle size
D50 =96.11 µm
D50=59.75 µm
D50 =24.01 µm
En
se
mb
le
0.0
0.5
1.0
1.5
2.0
2.5
Co
ars
e
Fra
ct.
tough,
KIC
(M
Pa
-√m
)
Fin
e
50µm
Fine powder cut
Case Study: Effect of particle size distribution 17
DOE UTSR Meeting, Oct 2014, Purdue University, IN
YSZ
as-sprayed
0 10 20 30 40 50 60 70 80
Indentation modulus, Eind (GPa)
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Fra
ctu
re toughness, K
IC (
MP
a-√
m) YSZ
sintered
ohigh sintering
rate
ohigh intrinsic
toughness
Fracture toughness and modulus relationship
o With sintering or
densification of
microstructure,
fracture toughness
increases.
o Toughness is more
sensitive towards
sintering FC
coarse
med E
highE
lowE
fine
150mm
18
E α 1/porosity
Fracture toughness is
sensitive to coating
microstructure
DOE UTSR Meeting, Oct 2014, Purdue University, IN
19 FCT life of various APS YSZ architectures
D
50 µm 50 µm
DVC
unmolten
particles
vertical
cracks
A B
50 µm 50 µm
C
50 µm
interlamellar
pores
globular
pores microcracks
FC
T L
ife
(H
ou
rs)
0
200
400
600
800
1000
FCT Hours
FCT Hours: 784.0000
A B C D
Typical APS coatings
DVC
FC
T L
ife (
Hours
) FCT carried out at
1100oC, 24 hrs cycle
In order to limit the
compliance loss
1. Porous coatings
2. DVCs
Generally, it has been
believed that the porous
TBCs last longer.
DOE UTSR Meeting, Oct 2014, Purdue University, IN
20
0
10
20
30
40
50
60
0
1
2
3
4
Ela
stic M
odulu
s (
GP
a)
Fra
ctu
re T
ou
gh
ne
ss (
MP
a
m)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
Therm
al C
onductivity (
W/m
K)
A B C D DVC*
FC
T L
ife
(H
ou
rs)
0
200
400
600
800
1000
FCT Hours
FCT Hours: 784.0000
DVC A B C D
Design requirements
Design requirements
1. High toughness : Improved Cyclic Life
2. Low modulus : Less driving force to failure
3. Low thermal conductivity : Low substrate temperature
Need a strategic approach towards
coating design for multi-functionality
Multiple requirements from a thermal barrier coating
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Substrate
Bond Coat
Primary Requirement
Elastic Modulus Fracture Toughness Thermal Conductivity
Durability Thermal Performance Compliance
Function of coating
microstructure
Processing strategies can control layer by layer coating properties
Multiple requirements from a thermal barrier coating 21
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Ni based Superalloy Substrate
Mu
ltila
ye
r To
pco
at
Bo
nd
co
at
Oxidation protection
strength/creep resistant
High fracture toughness layer
Sinter Resistant
Low Thermal conductivity
Erosion and CMAS Resistant
Low thermal conductivity
Phase stability
Teixeira et al., JTST, 9(2), 2000—191
Padture et al., vol. 296,Science, 280, 2002
Focus on need for high toughness ceramic at failure location 22
σis ≥ σc :Failure
DOE UTSR Meeting, Oct 2014, Purdue University, IN
23
Substrate
Bondcoat
TBC
U= 0
U = Ui
Low
stiffness
High
stiffness For constant hc
Uinterface α E (modulus)
Elastic Energy approach to optimize coating architecture
)()()1(2
)1( 2
ccsubc
c
isothermal hETU -
Levi et al., MRS Bulletin, 2012
Total Elastic Energy available for
interfacial crack propagation
Failure occurs when
Uinterface ≥ Gc
UiDense > Ui
Porous EDense > EPorous
Approach: Higher toughness with denser coatings…
DOE UTSR Meeting, Oct 2014, Purdue University, IN
24
Substrate
Bondcoat
TBC
U= 0
U = Ui
Low
stiffness
High
stiffness For constant hc
Uinterface α E (modulus)
Elastic Energy approach to optimize coating architecture
)()()1(2
)1( 2
ccsubc
c
isothermal hETU -
Levi et al., MRS Bulletin, 2012
Total Elastic Energy available for
interfacial crack propagation
Failure occurs when
Uinterface ≥ Gc
....)()1(2
)1(332211
2
ccccccsubc
c
isothermal hEhEhETU -
Derived from Levi et al., MRS Bulletin, 2012
For multilayer coatings
DOE UTSR Meeting, Oct 2014, Purdue University, IN
25 Revised TBC Architecture: Strategic approach for multi-functionality
Substrate
Bond Coat
Typical APS TBC
YSZ
as-sprayed
0 10 20 30 40 50 60 70 80
Indentation modulus, Eind (GPa)
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Fra
ctu
re toughness, K
IC(M
Pa-√
m) YSZ
sintered
FC
coarse
med E
highE
lowE
150mm
High Plasma
Power
Fine
Particles
Sintered for 24
hours
Substrate
Bond Coat
Functionally Optimized TBC with high
fracture toughness interface layer
High
Toughness
Layer
Porous layer for
lower modulus
Crack initiation due
to TGO growth
Structural
Compliance
DOE UTSR Meeting, Oct 2014, Purdue University, IN
26
50µm 50µm 50µm
Bi-layer with tough near-
interface layer Porous single layer Bi-layer with inverse
architecture
Revised TBC Architecture
Substrate
Bondcoat
Porous architecture
Conventional TBC
Substrate
Bondcoat Layer 1 : High toughness
Layer 2 : Low modulus
Optimal bi-layered TBC Inverse bi-layered TBC
Substrate
Bondcoat
Layer 1 : Low modulus
Layer 2 : High toughness
DOE UTSR Meeting, Oct 2014, Purdue University, IN
27 T
BC
lif
eti
me
(h
ou
rs)
0
200
400
600
800
1000
1200
1400
Co
nve
nti
on
al
Single layer
TBCs
Bi-layer
TBCs
Bi-layer
architecture
Inverse bi-layer
architecture
Porous Low near-
int. layer
KIC
FCT durability of revised TBC Architecture
YSZ
as-sprayed
0 10 20 30 40 50 60 70 80
Indentation modulus, Eind (GPa)
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Fra
ctu
re to
ug
hn
ess, K
IC(M
Pa-√
m) YSZ
sintered
FC
coarse
med E
highE
lowE
150mm
High Plasma
Power
Fine
Particles
Sintered for 24
hours
Consistent improvement in
TBC life for bi-layer coatings
With high toughness interface
layer
Do
ub
led
li
fe
DOE UTSR Meeting, Oct 2014, Purdue University, IN
28
Bi-layer with tough near-interface layer Conventional porous single layer Bi-layer with inverse architecture
Conventional
poro
us s
ingle
layer
50 µm
C1
50 µm
B5
bi-
layer
with
dense n
ear-
inte
rfa
ce
la
ye
r
50 µm
B3
bi-
layer
with
invers
e
arc
hitectu
re
epoxy epoxy epoxy
Failed Specimens
The failure location for all the architectures remains the same
Substrate
Bondcoat
Porous architecture
Conventional TBC
Substrate
Bondcoat
Layer 1 : High toughness
Layer 2 : Low modulus
Optimal bi-layered TBC Inverse bi-layered TBC
Substrate
Bondcoat
Layer 1 : Low modulus
Layer 2 : High toughness
DOE UTSR Meeting, Oct 2014, Purdue University, IN
29 Process optimization strategies
Superalloy Substrate
Overlay BC
Porous
YSZ
Low K
Low E
Conventional TBCs
Enhanced
Durability TBCs
Superalloy Substrate
Overlay BC enhanced
roughness
Layer-1
Layer-2
High KIC TBC Layer
Porous
YSZ
Low K
Low E
Ne
ar-
inte
rfa
ce la
ye
r K
IC, (M
Pa
m)
bi-layer
TBCs
Inverse
bi-layer TBC
15
Effective in- plane elastic modulus, E (GPa )
20 25 30 35 40 45 50 55
2.0
2.4
2.8
3.2
3.6
1.2
1.6
B5 B6
B7 Single layer
TBCs Property based
design map for
coatings with
enhanced
durability
TB
C life
tim
e (
hou
rs)
RT Thermal conductivity (W/m-K)
0.6 0.8 1.0 1.2 1.4 1.6 1.8
400
600
800
1000
1200
1400
Single layer
TBCs
bi-layer
TBCs with
improved
durability
Inverse
bi-layer TBC
Simultaneous
optimization of
coating durability
and functionality
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Traditional YSZ
New TBC Requirement
Phase Stability Good < 1200C Good<1300-1400C
Thermal Expansion Fair Challenging
Thermal Conductivity* Low Lower
Sintering Resistance* Fair Good
Erosion Resistance* Good Challenging
Fracture Toughness* Good Challenging
Mechanical Compliance known To be explored
Materials need for higher operating temp. and severe environments
Materials’ intrinsic properties
Can be optimized via processing strategies*
30
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Candidates for top coat composition under consideration
Material Composition Advantages Powder
YSZ 7-8wt% YSZ Stable below 1200 C, cost effective,
properties well-characterized
Various sources,
different levels
of purity
Zirconate La2Zr2O7 Pyrochlore, low thermal conductivity,
phase stability to 1400 C
Julich
Zirconate Gd2Zr2O7 Pyrochlore, low thermal conductivity,
phase stability to 1400 C, compatible
with YSZ
Saint Gobain,
Julich,
Co-doped 1.5mol%Yb2O3
1.5mol% Gd2O3
2.1mol% Y2O3
ZrO2
t’ phase, low thermal conductivity,
sintering resistant, compatible with
MCrAlY bond coat, high erosion
resistance
NASA
YSZ-Al-Ti YSZ+20mol%Al
+5mol%Ti
CMAS resistant Ohio State Univ
TBC Materials under considerations
31
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Exploring and processing new materials
Cluster-doped YSZ Gd2Zr2O7 La2Zr2O7
32
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Courtesy : Levi et al MRS Bulletin 2012
Challenges:
1. CMAS mitigation
2. High erosion/FOD
resistance
3. Compatibility with YSZ
100 μm
YSZ
Gd2Zr2O7
Transitioning to low K TBC: Gd2Z2O7 pyrochlores
All have significant
dependency on processing
33
DOE UTSR Meeting, Oct 2014, Purdue University, IN
SiO2 CaO FeO Al2O3 Cr2O3 MgO SO3 TiO2 SrO MnO K2O Na2O P2O6
29.7 25.4 14.8 14.7 5.1 3.6 1.8 1.1 1.0 0.9 0.8 0.6 0.2
34
Reaction zone
~100 µm
100 µm
Porous GDZ Dense GDZ
Reaction zone
~35 µm
100 µm
Dense GDZ seems to offer lesser Lignite ash penetration depth.
It also offer benefits in terms of erosion resistance.
However, it has high modulus, which will increase the overall strain energy
Coating microstructure for enhanced CMAS resistance
Courtesy: Prof. Nitin Padture
DOE UTSR Meeting, Oct 2014, Purdue University, IN
SiO2 CaO FeO Al2O3 Cr2O3 MgO SO3 TiO2 SrO MnO K2O Na2O P2O6
29.7 25.4 14.8 14.7 5.1 3.6 1.8 1.1 1.0 0.9 0.8 0.6 0.2
35
Reaction zone
~100 µm
100 µm
Porous GDZ Dense GDZ
Reaction zone
~35 µm
100 µm
Dense GDZ seems to offer lesser Lignite ash penetration depth.
It also offer benefits in terms of erosion resistance.
However, it has high modulus, which will increase the overall strain energy
Molten ash
wicking
DVC GZO
Lignite Ash
Isothermal treatment under CMAS like conditions
Potential candidate for Top layer
Coating microstructure for enhanced CMAS resistance
Courtesy: Prof. Nitin Padture
DOE UTSR Meeting, Oct 2014, Purdue University, IN
1300C-110h
1200C-110h
1300C-10h &
1200C-110h
Various duration at 1100C and
1200C
YSZ
New
TBC Th
erm
al C
on
du
cti
vit
y (
W/m
-K)
Larson Miller Parameter (LMP)
LMP = T(ln t + C)
Larson Miller Parameter (LMP): Temp and Time for thermal exposure
36
High K, Low
Sintering rate
Sintering behavior of new materials: Challenges
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Befo
re
After
Free standing bi-layer coatings
Isothermal exposure at 1200oC for 24 hours
LMP
42000 44000 46000 48000 50000 52000 54000 56000
Co
nd
ucitiv
ity (
W/m
K)
0.8
1.0
1.2
1.4
1.6
1.8
YSZ
Gd2Zr2O7
LMP (Larson Miller Parameter)
Tan et . al
Gd2Zr2O7
Big difference in sintering rates require microstructural modifications 37
DOE UTSR Meeting, Oct 2014, Purdue University, IN
GZO
as-sprayed
YSZ
as-sprayed
GZO
sintered
0 10 20 30 40 50 60 70 80
Indentation modulus, Eind (GPa)
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Fra
ctu
re toughness, K
IC (
MP
a-√
m) YSZ
sintered
o high sintering rate
o high intrinsic
toughness
o low sintering
rate
o low intrinsic
toughness
Toughness is an issues with Cubic pyrochlore, GDZ
o YSZ more sensitive to
processing than GDZ
o Equivalent sintering
affects YSZ fracture
toughness more than
GDZ
FC
coarse
med E
highE
lowE
fine
150mm
med E
highE lowE
fine
38
E α 1/porosity
DOE UTSR Meeting, Oct 2014, Purdue University, IN
39
GDZ
20µm
YSZ
20µm
SE
M
Filt
ere
d
G3
20µm
Y3
20µm
Larger microcracking in GDZ due to low toughness
Introduces
processing
challenges
DOE UTSR Meeting, Oct 2014, Purdue University, IN
100 μm
YSZ
Gd2Zr2O7
A
100 μm
YSZ
Gd2Zr2O7
B
100 μm
YSZ
Gd2Zr2O7
C
0
100
200
300
400
500
600
700
TB
C L
ifetim
e (
Hours
)
Sin
gle
La
ye
r P
oro
us Y
SZ
A B
C
Porous Med. Porosity Low Porosity
FCT durability of bi-layered YSZ and Gd2Zr2O7 coatings
Failed
At YSZ-GDZ
interface
40
100μm
YSZ layer
Spalled GDZ layer
Failed microstructure (C)
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Befo
re
After
Free standing bi-layer coatings
Isothermal exposure at 1200oC for 24 hours
LMP
42000 44000 46000 48000 50000 52000 54000 56000
Co
nd
ucitiv
ity (
W/m
K)
0.8
1.0
1.2
1.4
1.6
1.8
YSZ
Gd2Zr2O7
LMP (Larson Miller Parameter)
Tan et . al
Gd2Zr2O7
Big difference in sintering rates require microstructural modifications 41
Toughness of GDZ!!!
DOE UTSR Meeting, Oct 2014, Purdue University, IN
42
Y1
• YSZ and GDZ process property relationships • Process Map development
• Toughness, Lignite ash penetration depth, erosion
Y2
• Rough bond coat process optimization with 40% increase in FCT life
• Two layer dense BC layer
Y3
• bi-layer YSZ coating with two fold increase in FCT life, and maintaining low K
• High toughness interface layer, Elastic energy model
Y4 • Multilayer YSZ-GDZ coating system
• enhanced life, Lignite ash penetration minimization, erosion resistance
Systematic progress over past four years
DOE UTSR Meeting, Oct 2014, Purdue University, IN
43
CTSR
UTSR
Program
GE Aviation
Different FCT
cycling time
Praxair
Gradient Jet-test
Siemens
FCT
ORNL
Various cycling
time and
substrate
material
CTSR
Further reduction in the
cost- Bondcoat processing,
other TBC materials
CTSR
Burner rig testing with
CMAS attach
CTSR
TBC overhaul:
reclaimed substrates
Extension and evaluation of multilayer YSZ-GDZ coatings
CTSR
Deposition and testing
on an actual component
DOE UTSR Meeting, Oct 2014, Purdue University, IN
Gratefully acknowledged
Dr. Briggs While, Program Manager
Prof. Toshio Nakamura, Stony Brook University
Dr. Curtis Johnson, Rtd. GE GRC
Prof. John Hutchinson, Harvard university
Prof. Nitin Padture