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Electroformed Nanocrystalline Coatings An Advanced Alternative to

VIEWS: 7 PAGES: 21

									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
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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
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DoD   EPA

  DOE Strategic Environmental Research
            and Development Program
Improving Mission Readiness Through
      Environmental Research             SM




SERDP Program 1152
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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)




SERDP Program 1152
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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
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DoD   EPA

  DOE Strategic Environmental Research
            and Development Program
                                          Phase I Results
Improving Mission Readiness Through
      Environmental Research                                                           SM




     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 @ 450C
**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)




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




     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

SERDP Program 1152
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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




SERDP Program 1152
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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


 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




     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


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




     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)

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




     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.




SERDP Program 1152
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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)




SERDP Program 1152
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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


SERDP Program 1152
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