Tribo-corrosion maps for engineering materials:some new perspectives

Tribo-corrosion maps for engineering

materials:some new perspectives

M.M. StackDepartment of Mechanical

EngineeringUniversity of Strathclyde

Glasgow G1 1XJ, UK

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Aims of presenation Can maps be used to guide materials

engineers in materials processes involving tribological and aqueous corrosion processes….

If so, how can we construct such maps….

How may they be modified based on the nature of tribological contact and corrosive enviroment..

Tribo-corrosion Wear due to the combination of

tribological and corrosion parameters…

Tribological-velocity, load, temperature, particle size, impact angle, yield strength….

Corrosion-pH, electrochemical potential, Cl-…

Wear map of steels for dry sliding

Lim and Ashby, 1987

Inman, Rose and Datta, Wear, 2006.

Wear map for Nimonic 80A vs. Stellite 6

Erosion-oxidation map for steels at elevated temperatures

Sundararajan, 1990

Corrosion map for Fe in H2O assuming passivation by formation of Fe2O3

-1.6

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

-2 0 2 4 6 8 10 12 14 16

pH

E, v

olts

(SH

E)

Immunity

CorrosionH2

Passivation

Corrosion

O2

Pourbaix, 1966

Development of tribo-corrosion map in aqueous conditions

Erosion-oxidation map

Sliding wear map

Aqueous - corrosion map

Tribo-corrosion map

in aqueous conditions

Regime map of Fe for PH 7 based on Sundararajan's Model, no rebound is considered

0.1

1

10

100

-1 -0.8 -0.6 -0.4 -0.2 0 0.2

APPLIED POTENTIAL, V (SCE)

PART

ICLE

VEL

OCI

TY, m

s-1

PURE

ERO

SION

EROSION DOMINATED

EROSION DISSOLUTION

DISSOLUTION DOMINATED

DISSOLUTION EROSION

EROSION DOMINATED

EROSION PASSIVATION

PASSIVATION EROSION

PASSIVATION DOMINATED

Format Why use a wear or a corrosion

map? Some useful applications Development of tribo-corrosion

maps-from erosion to micro-abrasion—corrosion

Erosion-corrosion in aqueous conditions

Jana and Stack, 2004

Example of surface failed by erosion-corrosion

Polarization curve for Fe in aqueous media

ipass icritlo g i

ActiveActiveregionregion

Passive Passive regionregion

Transpassive Transpassive regionregion

E p

p o te n tia l , E

Possible interactions… Erosion can enhance corrosion i.e.

removal of a passive film Corrosion can inhibit erosion through

formation of an adherent ductile film Corrosion can enhance erosion

through dissolution of phases within the material-i.e. as in the case of MMCs

Kec = Ke + Kc

= {Keo + Ke} + {Kco+ Kc}

Ke = Keo + Ke

Kc = Kco+ Kc

Kec = Erosion- corrosion rate (measured)

Keo = Erosion in the absence of corrosion

Kco = Corrosion in absence of erosion

Ke = Change in erosion due to corrosion (synergistic effect)

Kc = Change in corrosion due to erosion (additive effect)

Kc = Total corrosion rate (estimated using Faraday’s law)

Erosion-corrosion interaction

Erosion-corrosion rate

EC C EK K K

Active Region

C CO C

C CO

K K K

K K

E EO E

E EO

K K K

K K

Passive Region

C CO C

C C

K K K

K K

E EO E

E EO

K K K

K K

Erosion-Corrosion Regimes

Erosion KC/KE 0.1

Erosion-Corrosion 0.1≤KC/KE 1

Corrosion-Erosion 1 ≤ KC/KE 10

Corrosion KC/KE ≥10

Mechanism of wastage …(landscape)...

Erosion-corrosion map for Fe


0.1

1

10

100

-1 -0.8 -0.6 -0.4 -0.2 0 0.2


PA

RT

ICL

E V

EL

OC

ITY

, m s-1

PU

RE

ER

OS

ION

EROSION DOMINATED

EROSION DISSOLUTION


DISSOLUTION EROSION

EROSION DOMINATED

EROSION PASSIVATION

PASSIVATION EROSION


Fe at pH 7


0.1

1

10

100

-1 -0.8 -0.6 -0.4 -0.2 0 0.2


PAR

TIC

LE

VE

LO

CIT

Y, m

s-1

PUR

E ER

OSI

ON

EROSION DOMINATED

EROSION DISSOLUTION


DISSOLUTION EROSION

EROSION DOMINATED

EROSION PASSIVATION

PASSIVATION EROSION


Pourbaix diagram for Fe (SHE)

Erosion-corrosion map for Fe (SCE)

Ni at pH 7

Pourbaix Diagram for Ni (SHE)

Erosion-corrosion map for Ni (SCE)

Regime map of Ni for PH 7 based on sundararajan's model, no rebound is considered

0.1

1

10

100

-1 -0.8 -0.6 -0.4 -0.2 0 0.2


PA

RT

ICL

E V

EL

OC

ITY

, m s-1

PUR

E E

RO

SIO

N

EROSION DOMINATED

EROSION DISSOLUTION


DISSOLUTION EROSION

Cu at pH 7

Regime map of Cu for PH 7 based on Sundararajan's model, no rebound is considered

0.1

1

10

100

-1 -0.8 -0.6 -0.4 -0.2 0 0.2


PA

RT

ICL

E V

EL

OC

ITY

, m s-1

PUR

E E

RO

SIO

N

EROSION DOMINATED

EROSION PASSIVATION

PASSIVATION EROSION


Pourbaix diagram for Cu (SHE)

Erosion-corrosion map for Cu (SCE)

Al at pH 7

Regime map of Al for pH 7 based on Sundararajan's model, no rebound is considered

0.10

1.00

10.00

100.00

-1 -0.8 -0.6 -0.4 -0.2 0 0.2


PA

RT

ICL

E V

EL

OC

ITY

, m s

-1


PASSIVATION EROSION

EROSION PASSIVATIONEROSION DOMINATED

Pourbaix diagram for Al (SHE)

Erosion-corrosion map for Al (SCE)

Comparison between erosion-corrosion regime maps at pH 5

FeNi

Cu Al

0.1

1

10

100

-1 -0.8 -0.6 -0.4 -0.2 0 0.2

APPLIED PO TENTIAL, V (SCE)

PA

RT

IC

LE

VE

LO

CIT

Y,

m s

-1

EROSION DOMINATED

EROSION DOMINATED

EROSION P ASSIVATION

P ASSIVATION EROSION

EROSION DOMINATED

PU

RE

ER

OS

IO

N

EROSION- DISSOLUTION

DISSOLUTION- EROSION


0.1

1

10

100

-1 -0.8 -0.6 -0.4 -0.2 0 0.2


PA

RT

ICL

E V

EL

OC

ITY

, m s

-1

PU

RE

ER

OS

ION

EROSION DOMINATED

EROSION DISSOLUTION


DISSOLUTION EROSION

0.1

1

10

100

-1 -0.8 -0.6 -0.4 -0.2 0 0.2


PA

RT

ICL

E V

EL

OC

ITY

, m s

-1

PU

RE

ER

OS

ION

EROSION DOMIONATED

EROSION PASSIVATION

PASSIVATION EROSION


0.1

1

10

100

-1 -0.8 -0.6 -0.4 -0.2 0 0.2


PA

RT

ICL

E V

EL

OC

ITY

, m s

-1


PASSIVATION EROSION

EROSION PASSIVATIONEROSION DOMINATED

Wastage rate …(metrics)...

Comparison between erosion-corrosion wastage

maps at pH 5

Fe

Cu

0

0.5

1

1.5

2

2.5

-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2


PAR

TIC

LE

VE

LO

CIT

Y, m

s-1

HIGH

MEDIUM

LOW

LOW

MEDIUM

0

0.5

1

1.5

2

2.5

-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2


PAR

TIC

LE V

ELO

CIT

Y, m

s-1

HIGHMEDIUM

LOW

0

0.5

1

1.5

2

2.5

-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2


PAR

TIC

LE

VE

LO

CIT

Y, m

s-1

HIGH

LOW MEDIUM

Ni

Al

0

0.5

1

1.5

2

2.5

-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2


PAR

TIC

LE V

ELO

CIT

Y, m

s-1

HIGH

MEDIUMLOW

Materials selection …(decision on most convenient route...

Comparison between materials performance

maps at pH 5

0

0.5

1

1.5

2

2.5

-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2


PA

RT

ICL

E V

EL

OC

ITY

, m s

-1

Fe+Ni+Cu

Ni+Cu Cu

Al+Fe+Ni+Cu

Fe

MEDIUM+HIGH WASTAGE

Comparison between materials performance

maps at pH 9

0

0.5

1

1.5

2

2.5

-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2


PA

RT

ICL

E V

EL

OC

ITY

, m s

-1

Fe+Ni+Cu

Ni+Cu Cu

Al+Fe+Ni+Cu

MEDIUM+HIGH WASTAGE

Erosion-corrosion of MMC Based materials

Abd-El-Badia and Stack, 2006-2007

Particles

Pumped Solution

Solution A.E

R.E

Shielding Enclosure Tilting to facilitate

angle adjustment Specimen

Holding Screw

Slurry

Specimen holder

Ejector

Potentiostat W.E

Erosion-corrosion rig

Based on design of Li, Burstein and Hutchings, 1990

Erosion-corrosion mechanisms of MMC based materials

Kec = Ke + Kc

= {Keo + Ke} + {Kco+ Kc}

Ke = Keo + Ke

Kc = Kco+ Kc

Kec = Erosion- corrosion rate (measured)

Keo = Erosion in the absence of corrosion

Kco = Corrosion in absence of erosion

Ke = Change in erosion due to corrosion (synergistic effect)

Kc = Change in corrosion due to erosion (additive effect)


Erosion-corrosion interaction


Erosion KC/KE 0.1

Erosion-Corrosion 0.1≤KC/KE 1

Corrosion-Erosion 1 ≤ KC/KE 10

Corrosion KC/KE ≥10


KC/ KE 0.1 Synergistic

0.1 KC/ KE ≤ 1 Additive- Synergistic

KC/ KE > 1 Additive

Erosion-corrosion mechanism maps

WC/Co-Cr coating

2 ms2 ms-1 impact velocity impact velocity 4 ms4 ms-1 impact velocity impact velocity

Erosion-corrosion wastage maps

WC/Co-Cr coating


Erosion-corrosion additive/synergistic effect maps

WC/Co-Cr coating



Erosion-corrosion Materials Performance maps

Erosion-corrosion of cermets

Stack, Antonov and Hussainova, 2006

SEM micrograph of surface of Ni-CR3C2 cermet with 40% wt. Ni. Potential - +500mV. Duration of test – 1

hour.

Erosion-corrosion maps for cermets

Stack, Antonov and Hussainova, 2006

Erosion-corrosion map showing the transition between different wastage regimes for a Cr3C2-

Ni cermet

6 % 8%

10%

Erosion-corrosion map showing the transition between different additive regimes for a Cr3C2-Ni cermet

6 % 8 %

10 %

Erosion-corrosion of PVD coatings

Purandare and Stack, 2004

Erosion-corrosion of PVD coatings

3 um

Surface of coating with macro defects

Exposure at +400mV and 90°

Surface after erosion-corrosion at +400 mV and 60°,

3 um

Micrographs of eroded coatings

10

20

30

40

50

60

70

80

90

-1500 -1000 -500 0 500

Imp

ac

t a

ng

le (d

eg

) Erosion only

Erosion-passivation Erosion-dissolution

Dissolution -erosion

Passivation -erosion

E (mV)

Mechanism map for CrN/NbN coating

Impact angle (deg)

20 30 45 60 90 -1000 mV

-400 mV

+400 mV

E (

mV

)

Wastage Map for CrN/NbN coating

HIGH

MEDIUM

LOW

Erosion-corrosion mechanisms maps for coated and uncoated materials

Micro-abrasion-corrosion

Mathew and Stack, 2005

Micro-abrasion corrosion apparatus

Load

Metallic

Specimen

Slurry solution

L -Shaped Arm

Rotating shaft supporting the ball

WE REAE

Potentiostat

Data collection

Counterface ball

Micro-abrasionDental environments

Micro-abrasionArtificial hip joints

Micro-abrasion process

Sample Material mild steel

Ball Material polypropylene (25 mm diameter)

Speed 100 RPM

Load 1-5N

Slurry silicon carbide (4 m)

Solution carbonate/bicarbonate (pH 9.8)

Experimental Details

-1000

-500

0

500

10-3

10-2

10-1

100

Current (mA/cm²)

Po

tentia

l (mV

)

Data Graph

1N

2N

3N

4N

5N

Polarization curves in carbonate/bicarbonate solution-no particles

-1500

-1000

-500

0

500

10-3

10-2

10-1

100

Current (mA/cm²)

Po

tentia

l (mV

)

Data Graph

1N

2N

3N4N

5N

Polarization curves in carbonate/ bicarbonate slurry

Variation of Kac, Ka and Kc with increasing load

At -0.60 V:

At -0.40 V:

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 1 2 3 4 5 6

Load (N)

We

igh

t lo

ss (

g x

10

-3 )

Kac

Kc

Ka

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 1 2 3 4 5 6

Load (N)

We

igh

t lo

ss (

g x

10

-3 )

Kac

Kc

Ka

Variation of Kac, Kc and Ka with increasing load

At 0 V

At -0.20 V

0

0.05

0.10.15

0.2

0.25

0.30.35

0.4

0.45

0 1 2 3 4 5 6

Load (N)

We

igh

t lo

ss (

g x

10

-3 )

Kac

Kc

Ka

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5 6

Load (N)

Wie

gh

t lo

ss (

g x

10-3 )

Kac

Kc

Ka

Variation of Kac, Kc and Ka with increasing load

At +0.20 V

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0 1 2 3 4 5 6

Load (N)

We

igh

t lo

ss (

g x

10-3

)Kac

Kc

Ka

At 1N and –0.2 V

SEM images of wear scar on mild steel

At 4N and –0.2 V

At 5N and –0.2 V

AFM of un-abraded steel surface

AFM of wear scar on mild steel at 1N and at +0.2 V

Micro-abrasion mechanisms

Schematic diagram of micro-abrasion mechanisms

(ii) Mixed regime

(iii) 2 body grooving

Particle entrainment

(i)3-body rolling

Rolling

3-2 body

(iv) a

(iv) b Oxide Film

2-body Wear

2-body wear

Surfaces in contact

2 body ridging

Transitions between regimes for the micro-abrasion process

Applied Load

Wea

r V

olum

e3-2 Body3-2 Body 2 Body

ridging

Results from current study

Wear-mode map for the micro-abrasion process (Adachi and Hutchings, 2003)

Hardness ratio Hs/Hb

1

10-3

0.01 0.1 1 10

Severity contact S ( =W/AvH’)

10-1

100

10-2

Micro-scale abrasion testThree-body

Mixed

Two-body

Three-body abrasion

Two-body abrasion

S’ =(Hs/Hb) =0.0076, = -0.49

Kac = Ka + Kc

= {Kao + Ka} + {Kco+ Kc}

Ka = Kao + Ka

Kc = Kco+ Kc

Kac = Micro-abrasion- corrosion rate (measured)

Kao = Micro-abrasion in the absence of corrosion (measured at –960 mV)

Kco = Corrosion in absence of micro-abrasion

Ka = Change in micro-abrasion due to corrosion

Kc = Change in corrosion due to micro-abrasion


Micro-abrasion-corrosion interaction

Micro-abrasion-corrosion regimes

Corrosion Kc/Ka > 10Corrosion-micro-abrasion 10> Kc/Ka > 1 Micro-abrasion-corrosion 1> Kc/Ka > 0.1Micro-abrasion Kc/Ka < 0.1

Corrosion? Active or passive conditions from polarization behaviour and Pourbaix diagrams

Micro-abrasion? 3 or 2 body behaviour identified using theoretical models

Micro- abrasion-corrosion mechanism map for mild steel/polypropylene couple

1

2

3

4

5

- 0.6 - 0.5 - 0.4 -0.3 -0.2 -0.1 0 0.1 0.2

Potential (V)

Load (N)

2- body- Active dissolution

2-body- Passivation

Passivation – 2 body

Active dissolution- 2 body

2-body -Active/Passive

Active / Passive 2 body

Passivation

Comparison between micro-abrasion-corrosion maps and polarization data

1

2

3

4

5

-0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2

Potential (V)

Load (N)


2-body- Passivation





Passivation

-1500

-1000

-500

0

500

10-3

10-2

10-1

100

Current (mA/cm²)

Po

tentia

l (mV

)

Data Graph

1N

2N

3N4N

5N

1

2

-0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2

Potential (V)

Medium

High

3

4

5

Load (N)

High

Micro-abrasion corrosion wastage map for mild steel/polypropylene couple

Comparison between micro-abrasion-corrosion maps and polarization data

-1500

-1000

-500

0

500

10-3

10-2

10-1

100

Current (mA/cm²)

Po

tentia

l (mV

)

Data Graph

1N

2N

3N4N

5N

1

2

-0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2Potential (V)

Medium

High

3

4

5

Load (N)

High

Comparison between micro-abrasion-corrosion maps

1

2

3

4

5

-0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2

Potential (V)

Load (N)


2-body- Passivation





Passivation

1

2

-0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2Potential (V)

Medium

High

3

4

5

Load (N)

High

Discussion Tribo-corrosion maps are a powerful tool

for identifying materials degradation mechanisms

Much work needs to be carried out on the theoretical development of the maps

These maps have the potential to be the future mainstream engineering tools for addressing materials issues in such environments

T.S.N. Sankara Narayanan, Y W. Park and K. Y. Lee Wear, 262,228-233 2007.

Fretting-Corrosion maps

Conclusions Progress has been made in recent years on

the development of tribo-corrosion maps Maps for particulate erosion, sliding wear

and micro-abrasion have been proposed in corrosive environments

Such techniques have potential applications to a wide range of materials issues exposed to tribological and corrosive environments.

Acknowledgements PhD students :T. Abd-El-Badia, M.

Antonov, B.D. Jana, M. Mathew, Y Purandare

Collaborators: P Hovespean, W. Huang, J Jiaren, I Hussaionova

Documents

Tribo-corrosion maps for engineering materials:some new perspectives