application of gdoes to study of corrosion protective...

Application of GDOES to Study of Corrosion Protective Coatings

MULTIPROTECT: The University of ManchesterMULTIPROTECT: The University of Manchester

Ruth Bingham, George Thompson, Peter Skeldon.

The University of Manchester

GD day 16th September 2016

Contents

• Background• MULTIPROTECT• Specimens

• Experimental


• Experimental• Glow discharge optical emission

spectroscopy (GDOES)• Artificial cells

• Results and discussion• Summary and conclusions, further work

Project backgroundMULTIPROTECT:• An integrated project of the 6th framework

programme of the European Commission.• A collaboration between 31 academic and


• A collaboration between 31 academic and industrial researchers from 13 countries.

• Aim: to provide novel, heavy-metal free, multifunctional, economical and environmentally friendly corrosion protecting surface treatments based on nanocomposite materials.

http://www.multiprotect.org/

Specimens: AA2024 T3


• EPOXY-Al sol-gel coatings (INM)• Non-inhibited• Inhibited: BZT or BZT in AluOx;

• Methacryloxy-based sol-gel coatings (EADS)• Methacryloxy-based sol-gel coatings (EADS)• Non-inhibited• SAPP-inhibitor in sol-gel,• Inhibitors in primer: BZT, MBT, MBI,

SrCrO4.

Experimental: RF-GDOES


• The sample is sputtered by Ar ions.• Neutral species

Arvacuum

window

λ

• Neutral species are accelerated in the plasma.• Light is emitted by the atoms when excited by collisions.

Vacuum

Cooling

Anode

SampleRF

Experimental: Artificial Cells


• Cells consisted of coated specimens fixed in close proximity to the bare alloy:

• Cells were filled with 35 g l-1 NaCl

ge

l w

ith

BZ

Tg

el w

ith

BZ

T • Cells were filled with 35 g l NaCl solution for (a) 5 h and (b) 200 h.

• Subsequent GDOES analysis of the bare alloy from each cell.

• Noted characteristics of elemental profiles.S

ol-g

el w

ith

BZ

T

AA

20

24

-T3

So

l-g

el w

ith

BZ

T

AA

20

24

-T3

Experimental: Artificial Cells


^ Artificial cells during exposure ^ Artificial cells deconstructed

after exposureBare alloy specimens were then sputtered. Raw data was imported to Excel and combined to compare profiles of individual elements.

Results and Discussion

Part 1:Elemental depth profiles of the bare alloy from cells incorporating


alloy from cells incorporating uninhibited coatings

Surf. Interface Anal. 2015, 47, 1009 – 1014

60

80

Inte

nsi

ty

sol-gel + primer

High-Inorganic sol-gel

Aluminium profiles of bare alloy


In the presence of coated specimens from EADS

0

20

40

0 1 2 3 4 5 6 7

Sputtering time (s)

Inte

nsi

ty High-Inorganic sol-gel

sol-gel + Zr

control

referenceSurface roughness > reference.

Surface roughness ≤ reference.

60

80

100

Inte

nsi

ty

EPOXY-Al



Surface roughness > control but < reference

0

20

40

60

0 1 2 3 4 5 6 7

Sputtering time (s)

Inte

nsi

ty

EPOXY-Al-AluOx

control

referenceSurface roughness ≥reference.

6

8In

ten

sity

sol-gel + primer

High-Inorganic sol-gel

sol-gel + Zr

Oxygen profiles of bare alloy


Sputtering times to achieve half-peak intensity:

1.15 s

1.15 s

1.06 s

Area under the curve indicates thickness of corroded or altered

0

2

4

0 1 2 3 4 5 6 7

Sputtering time (s)

Inte

nsi

ty

sol-gel + Zr

control

reference

1.06 s

1.04 s

1.24 s

corroded or altered layer

3

4

Inte

nsi

ty

EPOXY-Al

EPOXY-Al-AluOx



1.25 s

1.04 s

Sputtering times to achieve half-peak intensity:

0

1

2

0 1 2 3 4 5 6 7Sputtering time (s)

Inte

nsi

ty

control

reference

0.82 s

1.04 s

Copper profiles of bare alloy

8

10

12

Inte

nsi

ty


Note double peak for control specimen

Retention of second peak

0

2

4

6

0 1 2 3 4 5 6 7

Sputtering time (s)

Inte

nsi

ty

sol-gel + primer high-inorganic sol-gel

sol-gel + Zr control

referenceLoss of second peak indicates de-alloying and re-distribution of Cu

8

10

12

14

Inte

nsi

ty

EPOXY-Al


Copper profiles of bare alloyNote double peak for control specimen

Retention of second peak

0

2

4

6

8

0 1 2 3 4 5 6 7

Sputtering time (s)

Inte

nsi

ty

EPOXY-Al

EPOXY-Al-AluOx

control

reference

Loss of second peak indicates de-alloying and re-distribution of Cu

0.02

0.03

Inte

nsi

ty

EPOXY-Al

EPOXY-Al-AluOx

Chlorine profiles of bare alloy


Area under the curve indicates quantity of Cl sampled when sputtering through the corroded or altered

0

0.01

0 1 2 3 4 5 6 7

Sputtering time (s)

Inte

nsi

ty

control

reference

corroded or altered layers.

Results and Discussion

Part 2:Elemental depth profiles of the bare alloy from cells incorporating BZT-


alloy from cells incorporating BZT-inhibited coatings (INM)


60

70

80

90

100

EPOXY-Al-BZT



Surface roughness > control but < reference

0

10

20

30

40

50

60

0 1 2 3 4 5Sputtering time (s)

Inte

nsi

ty

EPOXY-Al-BZT

EPOXY-Al-BZT-AluOx

EPOXY-Al (uninhib.)

EPOXY-Al-AluOx (uninhib.)

control

reference

Surface roughness

≥ reference

2.5

3

3.5

4 EPOXY-Al-BZT

EPOXY-AL-BZT-AluOx

EPOXY-Al (uninhib.)


1.16 s

1.18 s

1.25 s

1.08 s



0

0.5

1

1.5

2

2.5

0 1 2 3 4 5

Sputtering time (s)

Inte

nsi

ty


control

reference

1.08 s

0.82 s

1.04 s

Values = Sputtering times to achieve half-peak intensity

8

10

12

14

Copper profiles of bare alloy


Note double peak for control specimen

Significant retention of second peak

Loss of second peak: de-alloying of Cu

0

2

4

6

8

0 1 2 3 4 5

Sputtering time (s)

Inte

nsi

ty

EPOXY-Al-BZT EPOXY-Al-BZT-AluOx

EPOXY-Al (uninhib.) EPOXY-Al-AluOx (uninhib.)

control reference

Loss of second peak: de-alloying of Cu

0.015

0.02

0.025EPOXY-Al-BZT

EPOXY-Al-BZT-AluOx

EPOXY-Al (uninhib.)


Chlorine profiles of bare alloy


Area under the curve indicates quantity of Cl

0

0.005

0.01

0.015

0 1 2 3 4 5

Sputtering time (s)

Inte

nsi

ty


control

reference

0.03

0.035

0.04

0.045In

ten

sity

EPOXY-Al-BZT

EPOXY-Al-BZT-AluOx

EPOXY-Al (uninhib.)


Nitrogen profiles of bare alloy


0

0.005

0.01

0.015

0.02

0.025

0 1 2 3 4 5

Sputtering time (s)

Inte

nsi

ty

reference

Area under the curve indicates quantity of N sampled. Result inconclusive.

Summary and conclusions


• Comparison of the intensity of corrosion of the bare alloy can be made by inspection of Al depth profiles.

• Comparison of thickness of corroded layers can be made by inspection of the O depth profiles.

• Assessment of extent of de-alloying and re-distribution of • Assessment of extent of de-alloying and re-distribution of Cu can be made by inspection of depth profiles.

• An inhibitory effect of the empty AluOx nanocontainers, due to chloride absorption, was inferred rom the Cl depth profiles.

• Presence of BZT inhibitor could not be confirmed by inspection of N depth profiles.

Additional Work


A third paper has been published detailing a study of depth profiles obtained by sputtering the bare alloy after corrosion in the presence of the inhibitor-doped specimens from EADS:inhibitor-doped specimens from EADS:


Thank you...


...any questions?

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