Transcript Kinetic Metallization

Kinetic
Metallization
Application of Oxidation/Corrosion Resistant Coatings
to Rocket Engine Combustion Chamber Liners
AeroMat 2004
June 10, 2004
Ralph Tapphorn and Don Ulmer
David Grimmett, Boeing-Rocketdyne
Linus Thomas-Ogbuji, NASA-GRC
Overview
Introduction to Kinetic Metallization
Application
Oxidation/Blanching Resistant Coatings for Combustion
Chamber Liners
Coating Properties
Tensile Properties
Thermal Conductivity
Oxidation Test Results
TGA
Cyclic Oxidation
Summary/Future Work
Kinetic Metallization
Impact Consolidation Process
Feed-stock: fine powder
Accelerant: inert light gas
Solid-state Consolidation
No Bulk Melting
No Liquid Chemicals
Environmentally Innocuous
No Particle or Hazardous Gas Emission
Process Flow
Powder fluidized using
pressurized He gas
(PFU)
He
PFU
Powder/gas mix
thermally conditioned to
improve deposition
efficiency (TCU)
Deposition nozzle
produces highly
collimated spray pattern Substrate
Area coverage using X-Y
rastering of nozzle and/or
rotation of substrate
TCU
Deposition
Nozzle
KM–CDS
First KM-CDS Shipped!!
Buyer: US Naval Academy
Located: NAVSEA-Carderock
Coating
Development
System
Desk sized
Production unit
Same footprint
Remove spray
enclosure
Application
MCC liner life in LOX/H2 engine SSME Main Combustion
limited by thermal ratcheting
Chamber (MCC)
failure initiated by cyclic
oxidation/ reduction (“blanching”)
of copper alloy liner
Desire high conductivity coating
that forms adherent, self healing
oxide that is stable in H2
Candidate coatings include CuxCr, where x = 20 to 30 vol.%
Study initiated to select optimum
composition of Cu-XCr based on
mechanical properties and
oxidation resistance
Advantages
KM vs. Thermal Spray
Eliminates:
Porosity
Oxygen pickup
Interlayer bond coats
Vacuum chamber
Coating Properties
KM Cu-Cr
Deposit
Bulk Cu-Cr specimens machined
from 10-mm thick KM deposits
Copper
Substrate
Tensile
Thermal Conductivity
Three Cu-Cr compositions
evaluated:
Thermal
Expansion
Specimens
Tensile
Specimens
Cu-20vol.%Cr
Cu-25vol.%Cr
Cu-30vol.%Cr
Thermal
Conductivity
Specimens
Tensile Properties
KM Cu-Cr tensile properties equivalent to wrought
Strength increases (ductility decreases) with increasing
Cr content
Strength (ksi) or Ductility (%)
60
Wrought
KM
Yield
Ultimate
Elong.
R.A.
50
40
30
20
10
0
Cu-15vol.%Cr
Cu-20vol.%Cr
Cu-25vol.%Cr
Cu-30vol.%Cr
Fractography
Ductile, microvoid coalescence observed at
room temperature
Thermal Conductivity
KM Cu-Cr thermal conductivity equivalent to wrought
Thermal Conductivity (Btu/hr-ft-F)
Conductivity decreases with increasing Cr content
200
180
160
140
120
100
80
60
Wrought Cu-15vol.%Cr
KM Cu-20vol.%Cr
KM Cu-25vol.%Cr
KM Cu-30vol.%Cr
40
20
0
0
500
1000
Temperature (deg-F)
1500
Oxidation Behavior
Evaluation of KM Cu-Cr
coated GRCop-84 TGA
coupons included:
Coating Adhesion
Static Oxidation
Cyclic Oxidation
KM Cu-Cr Coated GRCop84 TGA Coupons
KM Cu-25vol.%Cr
Three Cu-Cr compositions
evaluated:
Cu-20vol.%Cr
Cu-25vol.%Cr
Cu-30vol.%Cr
GRCop-84
Coating Adhesion
Coating adhesion improved by post-deposition heat
treatment
Sebastian Pull Strength (ksi)
14
12
As-Deposited
Annealed at 1700F/1hr/Ar
10
8
6
4
2
0
Note: Arrows indicate failure in epoxy
Cu-20vol.%Cr
Cu-25vol.%Cr
Cu-30vol.%Cr
Static
Oxidation
Formation of continuous Cr O layer
2
3
underneath external CuO slows oxidation rate
Oxidation rate decreases with increasing Cr
content
SpWt Gain (mg/sq-cm)
3
2.5
CuO
2
Cr2O3
1.5
Cu8Cr4Nb
1
w/Cu-17Cr
20Cr
0.5
Cu-Cr coating
w/Cu-21Cr
25Cr
0
0
4
8
12
Oxidation Time (H)
16
20
Cyclic Oxidation
Cyclic Temperature 77 ºK to 1023 ºK
Best oxidation resistance Cu-Cr Coating with 25vol% Cr
Spalling observed
1.02
1
Cu-25vol.%Cr
Relative Wt.
0.98
0.96
0.94
0.92
21.3Cr
25.0 Cr
0.9
17.1Cr
20.0 Cr
Cu-20vol.%Cr
0.88
0
4
8 12 16 20 24 28 32 36 40
Cycle # (15-Min. Cycles)
650ºC
750ºC
Summary
Kinetic Metallization achieves high
density, adherent Cu-Cr coatings
Eliminates need for interlayer bond coat
Eliminates oxygen pickup during spray process
Best balance of oxidation protection and
mechanical properties offered by Cu25vol.%Cr
Future Work
NASA initiated new program
to evaluate KM NiCrAlY
coatings for next-generation
LOX/kerosene engines
Preliminary work has shown
that low porosity, welladherent KM NiCrAlY coatings
can be applied to GRCop-84
No grit blasting surface
preparation required
No interlayer bond coat
required
KM NiCrAlY