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DoD EPA
DOE Strategic Environmental Research
and Development Program
Improving Mission Readiness Through
Environmental Research SM
Electroformed Nanocrystalline Coatings
An Advanced Alternative to
Hard-Chrome Electroplating
PP-1152
Dr. Maureen J. Psaila-Dombrowski, McDermott Technology, Inc.
Douglas E. Lee, Babcock & Wilcox Canada
Dr. Jonathan L. McCrea, Integran Technologies
Dr. Uwe Erb, University of Toronto
HCAT Meeting, Toronto, Ontario
August 30, 2001
SERDP Program 1152
DACA72-00-C-003 (8/30/01) 1
DoD EPA
DOE Strategic Environmental Research
and Development Program
Contents
Improving Mission Readiness Through
Environmental Research SM
Technical Objective
Nanocrystalline Materials
SERDP Program Overview
Phase I Results
Phase II Optimization
Phase II Next Step
SERDP Program 1152
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Technical Objective
Improving Mission Readiness Through
Environmental Research SM
Develop an environmentally benign advanced
nanocrystalline Co-based coating technology that:
Is compatible with conventional electroplating infrastructure
Will produce coatings that meet or exceed the overall
performance of hard chrome (hardness, wear, fatigue,
corrosion, and thermal stability)
Has costs similar to or less than life-cycle cost of existing
hard chrome electroplating processes
Will be applied to non-line-of-sight surfaces
SERDP Program 1152
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Nanocrystalline Materials
Improving Mission Readiness Through
Environmental Research SM
Introduction
Introduced 20 years ago
Enhanced volume fraction of the boundary
component
Superior mechanical properties
Produced by a variety of techniques:
Physical and chemical vapor phase processing
Mechanical attrition
Crystallization of amorphous precursors
Electrochemical methods
SERDP Program 1152
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Nanocrystalline Materials
Improving Mission Readiness Through
Environmental Research SM
Synthesis
Electrodeposited via conventional electroplating techniques
Single step process
Fully dense material - chemically homogeneous
Pure metals, binary/ternary alloys, composite materials
Broach choice of alloying constituents and bath chemistry
Pulsed power supply to favour nucleation of grains instead of
grain growth
Fixed or consumable anodes
Plated or freestanding material with a broad range of thickness
(1 to 1mm)
SERDP Program 1152
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DoD EPA
DOE Strategic Environmental Research
Nanocrystalline Materials
and Development Program
Improving Mission Readiness Through
Environmental Research SM
Structure
Solid, fully dense
electrodeposits (virtually
zero porosity)
Grains and well
characterized grain
boundaries (similar to
conventional
polycrystalline materials)
3 to 100nm grain size
SERDP Program 1152
DACA72-00-C-003 (8/30/01) 6
DoD EPA
DOE Strategic Environmental Research
and Development Program
Improving Mission Readiness Through
Environmental Research SM
SERDP Program 1152
DACA72-00-C-003 (8/30/01) 7
DoD EPA
DOE Strategic Environmental Research
and Development Program
Improving Mission Readiness Through
Environmental Research SM
Mechanical Properties of Conventional and Nanocrystalline Nickel
Nano-Ni Nano-Ni
Property Conventional †
100nm 10nm
Yield Strength, MPa (25oC) 103 690 >900
Yield Strength, MPa (350oC) – 620 –
Ultimate Tensile Strength, MPa (25oC) 403 1100 >2000
Ultimate Tensile Strength, MPa (350oC) – 760 –
Tensile Elongation, % (25oC) 50 >15 1
Elongation in Bending, % (25oC) – >40 –
Modulus of Elasticity, GPa (25oC) 207 214 204
Vickers Hardness kg/mm2 140 300 650
Work Hardening Coefficient 0.4 0.15 –
Fatigue Strength, MPa (108 cycles/air/ 25oC) 241 275 –
Wear Rate (dry air pin on disc), µm3/µm 1330 – 7.9
Coefficient of Frictionality (dry air pin on disc) 0.9 – 0.5
† ASM Metals Handbook, ASM International, Metals Park, OH. Vol. 2, p. 437 (1993)
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Program
Improving Mission Readiness Through
Environmental Research SM
Three Phases
Phase I Technology Viability Assessment
completed
Phase II Coating Optimization
in process
Phase III Extension to Complex Shapes
next year
SERDP Program 1152
DACA72-00-C-003 (8/30/01) 9
DoD EPA
DOE Strategic Environmental Research
and Development Program
Phase I Results
Improving Mission Readiness Through
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Go/No Go Nanocrystalline Material Data
Alloy I Alloy II Alloy III
Co-P Co-Mo Co-Fe-P
(0 to 5wt%P) (0 to 1wt%Mo) (15-30%Fe,2.5%P)
1) Grain size (nm) 8-14 8-14 15-25
2) Microhardness (VHN) 575-820* ~575 520-900**
3) Thermal Stability (C) 485 up to 497 425
4) Coating Thickness/ ≤ 0.010” ≤ 0.002” ≤ 0.05”
Integrity No N/A No
Pits/Pores Pits/Pores
*Hardness increases up to 1100 when heat treated 5 minutes @ 450C
**Hardness increases up to 1250 when heat treated 10 minutes @ 400°C
SERDP Program 1152
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Phase II
Improving Mission Readiness Through
Environmental Research SM
Select most promising alloy (Co-Fe-P) and optimize
composition, grain size and deposition process
cleaning and activation procedures
plating procedure
heat treatment procedure
grinding/polishing procedure
Apply to high strength and low strength carbon steel
substrates (.003 to .010” thickness)
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Phase II
Improving Mission Readiness Through
Environmental Research SM
Define formal testing requirements and conduct tests. Include pertinent
requirements from existing HCAT protocols and program data. Meet or
exceed hard chrome performance requirements.
Mechanical testing
hardness
tensile strength
ductility
adhesion
coefficient of friction
Performance testing
fatigue
corrosion
embrittlement
wear
Go / No-go decision
Reports and Review
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Phase III
Improving Mission Readiness Through
Environmental Research SM
Extension to Complex Shapes
Adapt processes and develop equipment for DoD non-line-
of-sight applications
Suitable anodes
Fluid delivery system
Optimized rate of deposition and coating quality
Apply optimized alloy composition developed in Phase I and
II to an actual DoD part/s for DoD evaluation
Identify coating inspection technique
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Program Plan
Improving Mission Readiness Through
Environmental Research SM
GFY00 GFY01 GFY02 GFY03
Phase I: Technological Viability Assessment
1. Alloy Synthesis
2. Material Characterization
3. Impact Assessment
4. Reporting/Management/Go-No Go
Phase II: Coating Application Optimization
5. Alloy Optimization
6. Mechanical Properties Testing
7. Material Performance Testing
8. Reporting/Management/Go-No Go
Phase III: Extension to Complex Shapes
9. Process Optimization
10. Anode and Production Equipment Design
11. Production Part Application
12. Material Performance Evaluation
13. Reporting/Management/Final Report
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Phase II Optimization
Improving Mission Readiness Through
Environmental Research SM
Co-Fe alloy
Variation of electrical parameters (I avg, pulse time, frequency)
Cobalt chloride-ferrous sulphate bath chemistry
Results
Electrodeposits demonstrated typical Hall-Petch strengthening
behaviour
Fe concentration in deposit not affected by pulse conditions
No definitive trend of hardness vs peak current density
Build up rates increased with increasing duty cycle but were below
expectations, but increased with addition of conducting salts
Experienced Fe depletion problems with bath aging
Samples made for salt spray corrosion and taber wear tests
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Phase II Optimization
Improving Mission Readiness Through
Environmental Research SM
Co-Fe-P alloy
Studied variation of electrical parameters, pH and metal
ion/conducting salt additions
Managed Fe depletion with complexing and reducing agents
Cobalt chloride-ferrous sulphate bath chemistry with
hypophosphorous acid addition
Results
Higher current densities increased Fe concentration in deposits. P content
independent of current density
Fe content increased with pH; P content decreased with pH
Grain size decreased with increasing P content
Plating rate significantly increased (.002 to .005”/hour) by conductive salt
addition (NaCI) and higher average current density; not increased by
higher metal ion concentration
Samples made for salt spray corrosion and taber wear tests
SERDP Program 1152
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Phase II Optimization
Improving Mission Readiness Through
Environmental Research SM
Taber Wear Screening Test Results
Tests performed per ASTM D4060, ASTM C501 and MIL-A-
8625F
Nanocrystalline Co and Co-P alloys have higher Taber
indices
Nanocrystalline Co-Fe-P alloys show significantly improved
Taber indices. Higher Fe and higher hardness better
60-70% Fe concentration represents limit for lowest wear
coefficient
SERDP Program 1152
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Improving Mission Readiness Through
Environmental Research SM
45
0wt%Fe 20wt%Fe 30wt%Fe 50wt%Fe
40
Co-3%Fe 60wt%Fe
510VHN
Taber Wear Index (mg/1000 cycles)
35
30 Co-32%Fe
340VHN 100wt%Fe
25 Co-19%Fe,1%P
467VHN
20
Co-29%Fe,3%P
884VHN
15
Co-Fe Alloys
10 Cobalt Alloys
Iron Alloys
5
Co-89%Fe,2%P
706VHN
0
0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008
Inverse Hardness (1/VHN)
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Phase II Optimization
Improving Mission Readiness Through
Environmental Research SM
Salt Spray Screening Test (ASTM B117)
>1200 hour exposure evaluated to ASTM D610 galleries
Nanocrystalline Co and Co-P alloys performed very well.
Heat treatment did not degrade corrosion performance.
Thicker coating performed better
Nanocrystalline Co-Fe on Co-Fe-P alloys performed very
poorly.
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Improving Mission Readiness Through
Environmental Research SM
ASTM B117 Testing
Carbon Steel Substrate
10
WC-Co HVOF - .004"
9 T400 HVOF - .004"
Hard Cr EP - .004"
8
Nano-Ni - .002"
7 NiLoP- .002"
ASTM B537 Ranking
Nano-Co - .002"
6
CoLoP- .002"
5 CoLoFeP- .002"
CoHiFeP- .002"
4
Note: Data for WC-Co,
3 T400 and Hard Chrome per
“Replacement of
2
Chromium Electroplating
Using HVOF Thermal
1
Spray Coatings”, Sartwell
0
et. Al.
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Exposure Time (hours)
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DoD EPA
DOE Strategic Environmental Research
and Development Program
Phase II Next Step
Improving Mission Readiness Through
Environmental Research SM
Investigate alternative alloy additions
Co-Fe-Zn
grain size: 4 to 29 nm
VHN: 500-600 as deposited
Plating rate: .004 - .006”/hour
Salt water corrosion: Co ~20% Fe ~20% Zn
Co-Fe-Zn-P
Co-Fe-W
Establish sliding wear performance
Procure fatigue and hydrogen embrittlement test
specimens
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