AeroMat 2004June 10, 2004

Ralph Tapphorn and Don UlmerDavid Grimmett, Boeing-Rocketdyne

Linus Thomas-Ogbuji, NASA-GRC

AeroMat 2004June 10, 2004

Ralph Tapphorn and Don UlmerDavid Grimmett, Boeing-Rocketdyne

Linus Thomas-Ogbuji, NASA-GRC

Kinetic

Metallization

Kinetic

Metallization

Application of Oxidation/Corrosion Resistant Coatingsto Rocket Engine Combustion Chamber Liners

Application of Oxidation/Corrosion Resistant Coatingsto Rocket Engine Combustion Chamber Liners

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

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

OverviewOverview

Impact Consolidation ProcessFeed-stock: fine powder

Accelerant: inert light gas

Solid-state ConsolidationNo Bulk Melting

No Liquid Chemicals

Environmentally InnocuousNo Particle or Hazardous Gas Emission

Impact Consolidation ProcessFeed-stock: fine powder

Accelerant: inert light gas

Solid-state ConsolidationNo Bulk Melting

No Liquid Chemicals

Environmentally InnocuousNo Particle or Hazardous Gas Emission

Kinetic Metallization

Kinetic Metallization

Powder fluidized using pressurized He gas (PFU)

Powder/gas mix thermally conditioned to improve deposition efficiency (TCU)

Deposition nozzle produces highly collimated spray pattern

Area coverage using X-Y rastering of nozzle and/or rotation of substrate

Powder fluidized using pressurized He gas (PFU)

Powder/gas mix thermally conditioned to improve deposition efficiency (TCU)

Deposition nozzle produces highly collimated spray pattern

Area coverage using X-Y rastering of nozzle and/or rotation of substrate

Process FlowProcess FlowHeHe

PFUPFU

TCUTCU

DepositionNozzle

DepositionNozzle

SubstrateSubstrate

Coating Development System

Desk sized

Production unit

Same footprint

Remove spray enclosure

Coating Development System

Desk sized

Production unit

Same footprint

Remove spray enclosure

KM–CDSKM–CDSFirst KM-CDS Shipped!!Buyer: US Naval AcademyLocated: NAVSEA-Carderock

First KM-CDS Shipped!!Buyer: US Naval AcademyLocated: NAVSEA-Carderock

MCC liner life in LOX/H2 engine limited by thermal ratcheting 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 Cu-xCr, where x = 20 to 30 vol.%

Study initiated to select optimum composition of Cu-XCr based on mechanical properties and oxidation resistance

MCC liner life in LOX/H2 engine limited by thermal ratcheting 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 Cu-xCr, where x = 20 to 30 vol.%

Study initiated to select optimum composition of Cu-XCr based on mechanical properties and oxidation resistance

ApplicationApplicationSSME Main Combustion

Chamber (MCC)SSME Main Combustion

Chamber (MCC)

AdvantagesAdvantages

KM vs. Thermal Spray

Eliminates:

Porosity

Oxygen pickup

Interlayer bond coats

Vacuum chamber

KM vs. Thermal Spray

Eliminates:

Porosity

Oxygen pickup

Interlayer bond coats

Vacuum chamber

Coating PropertiesCoating Properties

ThermalExpansionSpecimens

ThermalExpansionSpecimens

TensileSpecimens

TensileSpecimens

Thermal Conductivity

Specimens

Thermal Conductivity

Specimens

CopperSubstrateCopper

Substrate

KM Cu-CrDeposit

KM Cu-CrDeposit

Bulk Cu-Cr specimens machined from 10-mm thick KM deposits

Tensile

Thermal Conductivity

Three Cu-Cr compositions evaluated:

Cu-20vol.%Cr

Cu-25vol.%Cr

Cu-30vol.%Cr

Bulk Cu-Cr specimens machined from 10-mm thick KM deposits

Tensile

Thermal Conductivity

Three Cu-Cr compositions evaluated:

Cu-20vol.%Cr

Cu-25vol.%Cr

Cu-30vol.%Cr

Tensile PropertiesTensile PropertiesKM Cu-Cr tensile properties equivalent to wrought

Strength increases (ductility decreases) with increasing Cr content

KM Cu-Cr tensile properties equivalent to wrought

Strength increases (ductility decreases) with increasing Cr content

0

10

20

30

40

50

60

Cu-15vol.%Cr Cu-20vol.%Cr Cu-25vol.%Cr Cu-30vol.%Cr

Strength (ksi) or Ductility (%)

Yield

Ultimate

Elong.

R.A.

Wrought

Wrought

KMKM

FractographyFractographyDuctile, microvoid coalescence observed at room temperatureDuctile, microvoid coalescence observed at room temperature

Thermal Conductivity

Thermal ConductivityKM Cu-Cr thermal conductivity equivalent to wrought

Conductivity decreases with increasing Cr content

KM Cu-Cr thermal conductivity equivalent to wrought

Conductivity decreases with increasing Cr content

0

20

40

60

80

100

120

140

160

180

200

0 500 1000 1500Temperature (deg-F)

Wrought Cu-15vol.%Cr

KM Cu-20vol.%Cr

KM Cu-25vol.%Cr

KM Cu-30vol.%Cr

Oxidation BehaviorOxidation Behavior

Evaluation of KM Cu-Cr coated GRCop-84 TGA coupons included:

Coating Adhesion

Static Oxidation

Cyclic Oxidation

Three Cu-Cr compositions evaluated:

Cu-20vol.%Cr

Cu-25vol.%Cr

Cu-30vol.%Cr

Evaluation of KM Cu-Cr coated GRCop-84 TGA coupons included:

Coating Adhesion

Static Oxidation

Cyclic Oxidation

Three Cu-Cr compositions evaluated:

Cu-20vol.%Cr

Cu-25vol.%Cr

Cu-30vol.%Cr

KM Cu-Cr Coated GRCop-84 TGA

Coupons

KM Cu-Cr Coated GRCop-84 TGA

Coupons

KM Cu-25vol.%CrKM Cu-25vol.%Cr

GRCop-84GRCop-84

Coating AdhesionCoating Adhesion Coating adhesion improved by post-deposition heat treatment Coating adhesion improved by post-deposition heat treatment

0

2

4

6

8

10

12

14

Cu-20vol.%Cr Cu-25vol.%Cr Cu-30vol.%Cr

As-Deposited

Annealed at 1700F/1hr/Ar

Note: Arrows indicate failure in epoxyNote: Arrows indicate failure in epoxy

Static OxidationStatic Oxidation Formation of continuous Cr2O3 layer underneath external CuO slows oxidation rate

Oxidation rate decreases with increasing Cr content

Formation of continuous Cr2O3 layer underneath external CuO slows oxidation rate

Oxidation rate decreases with increasing Cr content

0

0.5

1

1.5

2

2.5

3

0 4 8 12 16 20

Oxidation Time (H)

SpWt Gain (mg/sq-cm)

Cu8Cr4Nb

w/Cu-17Cr

w/Cu-21CrCu-Cr coatingCu-Cr coating

CuOCuO

Cr2O3Cr2O3

20Cr

20Cr

25Cr25Cr

Cyclic OxidationCyclic OxidationCyclic Temperature 77 ºK to 1023 ºK

Best oxidation resistance Cu-Cr Coating with 25vol% Cr

Spalling observed

Cyclic Temperature 77 ºK to 1023 ºK

Best oxidation resistance Cu-Cr Coating with 25vol% Cr

Spalling observed

0.88

0.9

0.92

0.94

0.96

0.98

1

1.02

0 4 8 12 16 20 24 28 32 36 40

Cycle # (15-Min. Cycles)

Relative Wt. 21.3Cr

17.1Cr

25.0 Cr25.0 Cr

20.0 Cr20.0 Cr

Cu-25vol.%CrCu-25vol.%Cr

Cu-20vol.%CrCu-20vol.%Cr

650ºC650ºC 750ºC750ºC

SummarySummary

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 Cu-25vol.%Cr

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 Cu-25vol.%Cr

Future WorkFuture Work NASA initiated new program to evaluate KM NiCrAlY coatings for next-generation LOX/kerosene engines

Preliminary work has shown that low porosity, well-adherent KM NiCrAlY coatings can be applied to GRCop-84

No grit blasting surface preparation required

No interlayer bond coat required

NASA initiated new program to evaluate KM NiCrAlY coatings for next-generation LOX/kerosene engines

Preliminary work has shown that low porosity, well-adherent KM NiCrAlY coatings can be applied to GRCop-84

No grit blasting surface preparation required

No interlayer bond coat required

KM NiCrAlYKM NiCrAlY