Studies on Alloys and Composites that Undergo Anomalous Codeposition

Murali RamasubramanianCenter for Electrochemical EngineeringDepartment of Chemical EngineeringUniversity of South Carolina


Dissertation DefenseApril 09, 1998


Studies on Alloys and Composites that Undergo Anomalous Codeposition

Studies on Alloys and Composites that Undergo Anomalous Codeposition

Murali RamasubramanianCenter for Electrochemical EngineeringDepartment of Chemical Engineering

University of South CarolinaColumbia, SC-29208

April 09, 1998

Murali RamasubramanianCenter for Electrochemical EngineeringDepartment of Chemical Engineering

University of South CarolinaColumbia, SC-29208

April 09, 1998





Systems Studied Systems Studied Systems Studied

Fe-Ni alloys and Fe-Ni-SiO2 compositesElectrodeposition

CorrosionMathematical Model for Electrodeposition

Zn-Ni alloys and Zn-Ni-SiO2 compositesElectrodeposition (D.C., Pulse)Corrosion and Hydrogen PermeationMathematical Model for Hydrogen Permeation

Fe-Ni alloys and Fe-Ni-SiO2 compositesElectrodeposition

CorrosionMathematical Model for Electrodeposition

Zn-Ni alloys and Zn-Ni-SiO2 compositesElectrodeposition (D.C., Pulse)Corrosion and Hydrogen PermeationMathematical Model for Hydrogen Permeation





Anomalous Alloys Anomalous Alloys -- ApplicationsApplications





Anomalous Alloys Anomalous Alloys -- ApplicationsApplications

−+ +→ e2ZnZn 2

2He2H2 →+ −+

Iron

Zn-Ni





Anomalous CodepositionAnomalous CodepositionAnomalous Codeposition

When certain metals are codeposited from certain solutions under certain conditions, the less noble metal deposits preferentially over the more noble one

When certain metals are codeposited from certain solutions under certain conditions, the less noble metal deposits preferentially over the more noble one





-0.7 V

Cathodic (less noble) Fee2Fe 2 →+ −+-0.44 V

-0.25 V Nie2Ni 2 →+ −+

HeH →+ −+0.00 V





Anomalous CodepositionAnomalous CodepositionAnomalous Codeposition

Metals such as:

Fe, Co, Ni (Iron group; VIII B)

Zn, Cd, Pb

Not due to the faster kinetics of the less noble metal

Temperature, current density, and bath composition are critical factors

Metals such as:

Fe, Co, Ni (Iron group; VIII B)

Zn, Cd, Pb

Not due to the faster kinetics of the less noble metal

Temperature, current density, and bath composition are critical factors





Objectives: Fe-Ni SystemObjectives: FeObjectives: Fe--Ni SystemNi System

To study the deposition and to characterize the corrosion resistance of Fe-Ni alloys and Fe-Ni-SiO2

composites

To develop a mathematical model that will explain Fe-Ni deposition and SiO2 inclusion

To study the deposition and to characterize the corrosion resistance of Fe-Ni alloys and Fe-Ni-SiO2

composites

To develop a mathematical model that will explain Fe-Ni deposition and SiO2 inclusion





Why SiO2 ?Why SiOWhy SiO2 2 ??

SiO2 films on certain metals forms a barrier layer to reduce metal dissolution rate*

Electrodeposited Zn-SiO2 composites show good corrosion resistance**

SiO2 composites with permalloy also provide excellent soft magnetic properties

* Kato. K, J. Mat. Sci., 28, 4033 (1993).* Hashimoto. S and Abe. M, Corr. Sci., 36, 2125 (1994).

SiO2 films on certain metals forms a barrier layer to reduce metal dissolution rate*

Electrodeposited Zn-SiO2 composites show good corrosion resistance**

SiO2 composites with permalloy also provide excellent soft magnetic properties

* Kato. K, J. Mat. Sci., 28, 4033 (1993).* Hashimoto. S and Abe. M, Corr. Sci., 36, 2125 (1994).





1.0 1.1 1.2 1.3 1.4

-E (V vs. SCE)

0.2

0.3

0.4

0.5

0.6Fe

Wei

ght F

ract

ion

Effect of Electrode Rotation Speed on Fe Weight Fraction

0.5 M NiSO4 + 0.1 M FeSO4 + 0.5 M Na2SO4, pH=3.0

500 rpm

10001500

1.0 1.1 1.2 1.3 1.4

-E (V vs. SCE)

0.2

0.3

0.4

0.5

0.6Fe

Wei

ght F

ract

ion

Effect of Electrode Rotation Speed on Fe Weight Fraction

0.5 M NiSO4 + 0.1 M FeSO4 + 0.5 M Na2SO4, pH=3.0

500 rpm

10001500





1.1 1.2 1.3 1.4 1.5-E (V vs. SCE)

30

35

40

45

50

55W

eigh

t Per

cent

Fe

Effect of SiO2 colloid on Fe Weight Fraction 0.5 M NiSO4 + 0.025 M FeSO4 + 0.5 M Na2SO4; pH=3.0

100 g/l SiO2

30

10

1.1 1.2 1.3 1.4 1.5-E (V vs. SCE)

30

35

40

45

50

55W

eigh

t Per

cent

Fe

Effect of SiO2 colloid on Fe Weight Fraction 0.5 M NiSO4 + 0.025 M FeSO4 + 0.5 M Na2SO4; pH=3.0

100 g/l SiO2

30

10





-1100 -850 -600 -350 -100 150

E (mV vs SCE)

-0.015

-0.005

0.005

0.015

0.025C

urre

nt (A

)

Cyclic Voltammogram's obtained for various SiO2 Concentrations

0.5 M NiSO4 + 0.1 M FeSO4 + 0.5 M Na2SO4; pH=3.0

Scan Rate 10 mV/s

0 g/l SiO2

20

50

H2

-1100 -850 -600 -350 -100 150

E (mV vs SCE)

-0.015

-0.005

0.005

0.015

0.025C

urre

nt (A

)

Cyclic Voltammogram's obtained for various SiO2 Concentrations

0.5 M NiSO4 + 0.1 M FeSO4 + 0.5 M Na2SO4; pH=3.0

Scan Rate 10 mV/s

0 g/l SiO2

20

50

H2





0 1 2 3 4 5Vol % SiO2 in Solution

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8V

ol. f

ract

ion

SiO

2 in

depo

sit

Relation between Volume Fraction of SiO2 in Deposit and in Solution

-1.1 V

-1.5 V

-1.3 V

0 1 2 3 4 5Vol % SiO2 in Solution

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8V

ol. f

ract

ion

SiO

2 in

depo

sit

Relation between Volume Fraction of SiO2 in Deposit and in Solution

-1.1 V

-1.5 V

-1.3 V





Schematic of a two-step inclusion ProcessSchematic of a two-step inclusion Process

N. Guglielmi, J. Electrochem. Soc., 119, 1009 (1972).

SubstrateSolution

θ

ϕ





SiO2 InclusionSiOSiO22 InclusionInclusion

Volume of SiO2 included:

)BEexp(vdt

dv0SiO

SiO2

2 θ=





Model ReactionsModel ReactionsModel ReactionsNi Deposition*

Fe Deposition

H2 Evolution

* M. Ramasubramanian, S. N. Popova, B. N. Popov, R. E. White, and K. M. Yin, J. Electrochem. Soc., 143, 2164 (1996).

( ) −−+ +→+ OHNie2OHNi

( ) −−+ +→+ OHFee2OHFe

2He2H2 →+ −+





Mathematical Model Mathematical Model Mathematical Model

Predicts the effect of various plating parameters on the alloy composition and current efficiencyMass transfer is governed by convection, diffusion and migrationRotating disk electrode; steady stateThe system of coupled non-linear equations is

solved by finite difference technique, using BAND routine.





1.0 1.1 1.2 1.3 1.4 1.5-E (V vs SCE)

0

2

4

6

8

10

12

14

16

18

i Fe (m

A/c

m2 )

Experimental and Theoretical iFe for various SiO2 concentrations

0 g/l SiO2

100

30

20

1.0 1.1 1.2 1.3 1.4 1.5-E (V vs SCE)

0

2

4

6

8

10

12

14

16

18

i Fe (m

A/c

m2 )

Experimental and Theoretical iFe for various SiO2 concentrations

0 g/l SiO2

100

30

20





1.1 1.2 1.3 1.4 1.5

-E (V vs SCE)

0.0

0.1

0.2

0.3

0.4

0.5W

t Fra

ctio

n Si

O2

Model Predictions and Experimental Data for Mass Fraction of SiO2

100 g/l SiO2

3

10

30

1.1 1.2 1.3 1.4 1.5

-E (V vs SCE)

0.0

0.1

0.2

0.3

0.4

0.5W

t Fra

ctio

n Si

O2

Model Predictions and Experimental Data for Mass Fraction of SiO2

100 g/l SiO2

3

10

30





-7 -6 -5 -4 -3 -2log [i] (i in A/cm2)

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

E (V

vs.

SCE)

Tafel Plots for Fe-Ni-SiO2 deposits for various SiO2 concentrations

0 g/l SiO2

25

50

-7 -6 -5 -4 -3 -2log [i] (i in A/cm2)

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

E (V

vs.

SCE)

Tafel Plots for Fe-Ni-SiO2 deposits for various SiO2 concentrations

0 g/l SiO2

25

50





0 1 2 3 4Corrosion rate (mpy)

Fe - Ni - SiO2 41 45 14

Fe - Ni - SiO2

43 47 10

Fe - Ni - SiO2

45 48 7

Fe - Ni - SiO2

48 49 3Fe - Ni50 50

Com

posi

tes

Corrosion Rate of Various Fe-Ni-SiO2 Composites

0 1 2 3 4Corrosion rate (mpy)

Fe - Ni - SiO2 41 45 14

Fe - Ni - SiO2

43 47 10

Fe - Ni - SiO2

45 48 7

Fe - Ni - SiO2

48 49 3Fe - Ni50 50

Com

posi

tes

Corrosion Rate of Various Fe-Ni-SiO2 Composites





Objectives: Zn-Ni System Objectives: ZnObjectives: Zn--Ni System Ni System To develop a methodology for the deposition of corrosion and hydrogen permeation resistant Zn-Ni-SiO2 composites*

Develop a mathematical model for characterizing the hydrogen permeation under corroding conditions, and determine the effect of Zn-Ni as hydrogen permeation inhibitor**

* B. N. Popov, M. Ramasubramanian, S. N. Popova, R. E. White, and K.-M. Yin, J. Chem. Soc. Faraday Trans., 92, 4021 (1996)

** M. Ramasubramanian, B. N. Popov, and R. E. White, J. Electrochem. Soc., 145, 1907 (1998)

To develop a methodology for the deposition of corrosion and hydrogen permeation resistant Zn-Ni-SiO2 composites*

Develop a mathematical model for characterizing the hydrogen permeation under corroding conditions, and determine the effect of Zn-Ni as hydrogen permeation inhibitor**

* B. N. Popov, M. Ramasubramanian, S. N. Popova, R. E. White, and K.-M. Yin, J. Chem. Soc. Faraday Trans., 92, 4021 (1996)

** M. Ramasubramanian, B. N. Popov, and R. E. White, J. Electrochem. Soc., 145, 1907 (1998)





0 10 20 30 40 50 60

i (mA/cm2)

86

88

90

92

94

96W

t % Z

nWeight Percent of Zinc in Electrodeposited Zn-Ni Alloy

0.5 M NiSO4 + 0.1 M ZnSO4 +0.5 M Na2SO4, pH = 3.0





-9 -8 -7 -6 -5 -4 -3 -2

log(i) (i in A/cm2)

-1.20

-1.15

-1.10

-1.05

-1.00

-0.95

-0.90

E (V

vs.

SCE)

Tafel Plots for Various Zn-Ni-SiO2 Composites

0 g/l SiO2

48





Hydrogen PermeationHydrogen PermeationHydrogen Permeation

Hydrogen in steel can cause damage via:Hydrogen EmbrittlementHydrogen BlisteringHydrogen Induced Cracking

Hydrogen Permeation can be inhibited by:Inhibiting the adsorption reaction rateIncreasing the recombination reaction rateDecreasing the amount of absorbed hydrogenForming a diffusion barrier





Hydrogen PermeationHydrogen Permeation

MHeHMH

MHeHM

2ads

ads

+→++

→++−+

−+Iron

−+ +→ e2ZnZn 2

Zn-Ni





Hydrogen Permeation SetupHydrogen Permeation SetupHydrogen Permeation Setup





0 10000 20000 30000Time (s)

15

20

25

30

35

40j ∞

(µA)

-1.00

-0.95

-0.90

-0.85

-0.80

-0.75

E c (V

vs.

SCE)

Ec and j∞ for Electrodeposited Zn-Ni in pH=5.2 Solution

0 10000 20000 30000Time (s)

15

20

25

30

35

40j ∞

(µA)

-1.00

-0.95

-0.90

-0.85

-0.80

-0.75

E c (V

vs.

SCE)

Ec and j∞ for Electrodeposited Zn-Ni in pH=5.2 Solution





0 1000 2000 3000 4000 5000 6000 7000 8000Time (s)

10

20

30

40

50

60Pe

rmea

tion

Cur

rent

(µA) 2.2

4.5

6.0

pH=7.0

Permeation current densities for a Zn-Ni alloy at various solution pH in the Cathodic compartment





2 3 4 5 6 7pH

10-5.0000

10-4.0000

10-3.0000

i (A

/cm

2 )Steady State ic and j∞ for iron and Zn-Ni Alloy

ic, Zn-Ni

jinf, Fe

ic, Fe

jinf, Zn-Ni





SummarySummarySummary

Studied the characteristics of electrodeposited corrosion resistant Fe-Ni-SiO2 composites Developed a mathematical model for the electrodeposition of anomalous alloys under potentiostatic conditionsExtended the above model was to include inert particle inclusion by a two step adsorption mechanism





SummarySummarySummaryCharacterized the electrodeposition of Zn-Ni alloys and Zn-Ni-SiO2 compositesStudied the hydrogen permeation characteristics of Zn-Ni alloys and Zn-Ni-SiO2 composites under applied polarization and corroding conditionsDeveloped a model for hydrogen permeation through substrates under corroding conditionsStudied the effectiveness of Zn-Ni alloys as hydrogen permeation inhibitors using the above model





Other Projects Worked OnOther Projects Worked OnOther Projects Worked OnElectroless deposition of copper on Pd-Catalyzed Polyimide Substrates: Experimental Study and Mathematical Model

Solution equilibrium characteristics of electroless copper on thermally activated palladium-catalyzed polyimide substrates, M. Ramasubramanian, B. N. Popov, R. E. White, and K. S. Chen, J. Appl. Electrochem., 28, 1998.

A mathematical model for electroless copper deposition on planar electrodes, M. Ramasubramanian, B. N. Popov, R. E. White, and K. S. Chen, J. Electrochem. Soc., submitted (January, 1998).

Passivation of iron in alkaline environmentsInhibiting action of calcium nitrite on steel rebars, M.

Ramasubramanian, B. N. Popov, and R. E. White, in ‘Materials for the New Millenium,’ Ken. P. Chong Ed., Published by the American

Society of Civil Engineers, New York, 2, 1007 (1996).

Studies on Alloys and Composites that Undergo Anomalous Codeposition

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