comparison between wet deposition and plasma deposition of ... · deposition of silane coatings on...

Comparison between wet deposition and plasma deposition of silane coatings on metals for surface

passivation

I. De Graeve, F. Brusciotti, A. Batan, M.Wenkin, F. Reniers, J.J. Pireaux, M. Piens, J.Vereecken, H. Terryn

VUB-ULB-FUNDP-CoRIi-SUP2008

FOMOS project

Functional properties by Mixed Nano Organic/Metal Oxide Systems

Acknowledgment for funding: Belgian Science Policy – Belspo“Programme to stimulate knowledge transfer in areas of strategic

importance”

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Consortium

VUBFUNDP ULB

CoRI

Fundamentals

Applied

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Users committee

• Bekaert Technology Center• Aleris Aluminium• R&D Umicore• OCAS-Arcelor Zelzate• Arcelor Research Industry Liège• Coil Landen• Chemetall GmbH • Akzo Nobel Decorative Coatings• SIGMAKALON• IWT

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Main question in the project

Starting point: concept of organic coating of metals

System 1: layered system of metal with native oxide and organic pretreatment coating (< 1µm)

System 1

Metal

Organic layer

Native oxide

Main question in FOMOS :How to improve properties and/or create innovative properties?

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What properties ?

• Mechanical– Hardness– Tribological: friction, wear…– Thermomechanical

• Functional !!! >>> main focus of FOMOS– Corrosion: barrier, inhibitors, self-healing…– Adherence, interfacial bonding…– Optical: appearance, reflectance, colour...– Ageing and chemical stability…– Wettability, hydrophobic/hydrophilic…– Other innovative properties….

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Approach in the project =Investigation of innovative systems (1)

System 2: layered system with tailored metal oxide layer

Metal

Organic layer

Native oxide

System 2

Oxide

Metal

Organic layer

System 1

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Approach in the project =Investigation of innovative systems (2)

System 3: hybrid system of mixed organic / metal oxide nanoparticle coating

System 3

Metal

oxide

Metal

Organic layer

Native oxide

System 2

Oxide

Metal

Organic layer

System 1

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Variables

System 1

Metal

Organic layer

Native oxide

System 2

Oxide

Metal

Organic layer

System 3

Metal

oxide

Organic medium: silanes (multimetal ! hybrid organic- inorganic chemistry)

Metal oxide: Si-oxide, Ce-oxide

Coating deposition method !!! - Wet deposition from solutions (water-based)- Solvent free plasma deposition: vacuum and atmospheric

Substrate and pre - and post-treatments:- Aluminium, steel- Precleaning method (chemical or plasma)- Curing of the organic system (thermally induced or during plasma deposition)

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Critical focus points

System 1

Metal

Organic layer

Native oxide

System 2

Oxide

Metal

Organic layer

System 3

Metal

oxide

• Compatibility between inherently very different media>>> Organic molecules versus inorganic metal oxide: interfacial bonding?

• Film formation mechanisms using the various deposition methods? …resulting properties?

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Characterisation Tools

Organic solution characterisation>>> DLS, NMR

Coating characterisation>>> FEG-SEM, FEG-AES, XPS, Tof-SIMS, GDOES, FIB TEM... Vis & IR-SE, Raman,…

Properties characterisation>>> Corrosion standard tests, EIS,… thermomechanical DSC,

TGA, DMA…adherence…optical TIS … wettability contact angle...

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What are silanes ?

Alternative to CrVI+ surface treatments for corrosion protection

Multimetal process on aluminium, steel, magnesium, zinc …

Silanes = hybrid organic-inorganic molecules

H5C

2O Si

OC2H

5

OC2H

5

(CH2)

2Si

OC2H

5

OC2H

5

OC2H

5 H O Si

OH

OH

(CH2)

2Si

OH

OH

OHhydrolysis

= Very reactive towards metal-film bonding and crosslinking

BTSE = bis-1,2-(triethoxysilyl)ethane

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Part 1: Wet deposition of silane

Metal

Organic layer

Native oxide

System 1

FEG-SEM secondary electron images roll-coated layers on aluminium

0.5 wt% BTSE 2.5 wt% BTSE

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⇒ Film morphology depending on solution concentration and wet deposition method (roll-coating vs dipcoating)

Part 1: Wet deposition of silane

Metal

Organic layer

Native oxide

System 1

Formation of hydrogen bonds

Interfacial bond formation

⇒ Strong covalent metal-film bonding; good adhesion

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Part 1: Wet deposition of silane + nanoparticles

Metal

MeOx

System 3

• CeO2 nanoparticles (10-20nm) for barrier properties and as nano-carriers for corrosion inhibitors

• Ce(NO3)3 for self-healing properties

In collaboration with: - Instituto Superior Técnico, ICEMS, Lisboa (Fatima Montemor)- Centre de Recherche Public Henri Tudor (CRP-HT), Luxembourg- Umicore

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FEG-SEM / EDX

Al 99.99% electropolishedSpin/dip Coated with BTSE 5 wt% + 250ppm CeO2+ 250ppm Ce(NO3)3

Metal

MeOx

Thickness is in agreement with VISSE results!

System 3

⇒ Agglomeration of nanoparticles

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FEG-SEM / EDX

Metal

MeOx

System 3

⇒ Agglomeration should be avoided by improved solution preparation

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XPS: bonding between silane and MeOxnanoparticle?

0712030015.SPE: na sputteren: Company Name2007 Dec 3 Mg std 350.0 W 0.0 µ 0.0° 23.50 eV 5.5438e+004 max 3.67 minCe3d/Area1/1 (Shft)

8808858908959009059109159209259303

3.5

4

4.5

5

5.5

6x 104 0712030015.SPE

Binding Energy (eV)

c/s

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Metal

MeOx

System 3Experiment: XPS on CeO2 powder pellet

Ce XPS signals

XPS: bonding between silane and MeOxnanoparticle?

Metal

MeOx

System 30803040024.SPE: CeO2: Company Name2008 Mar 4 Mg std 200.0 W 0.0 µ 0.0° 23.50 eV 2.8903e+004 max 25.94 minCe3d/Area1/1 (Shft)

8808909009109209302

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9x 104 0803040024.SPE

Binding Energy (eV)

c/s

Experiment: XPS on CeO2 powder pellet + drop of BTSE

Ce XPS signals

⇒ Indication of additional type of Ce environment⇒ Possible evidence of silane bond formation on Ce-oxide pellet

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Wet deposition of silane + nanoparticles

Metal

MeOx

System 3

Film properties ? Effect of wet deposition process conditions on properties ?

Ongoing work….

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Part 2: Plasma deposition

Differences with wet deposition?

- Silane vapour is carried by argon gas into the plasma

- Silane is (partially?) decomposed by collision with plasma components

- What is being deposited???

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Part 2 .1: Atmospheric plasma deposition

Thermostat

Chemical bubblerPlasma source

Sample support

Precursor Inlet

Showerhead25 mm of diameter

Coating material BTSE vapour at 100°C (from concentrated solution)

Gas discharge Argon

Substrate to showerhead distance 5 mm

Power 40 to 80 W

Argon flow 23.9 l/min

Deposition time 30 to 300 s

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Part 2.1: Atmospheric plasma deposition

1390 C-H symmetric bending (-CH3)1154 Si-O-C (-SiOCH2CH3)912 Si-O-C symmetric stretching (-SiOCH2CH3)712 C-H rocking

Peak position (cm-1) Assignement

Wavenumber (cm-1)

1000200030004000

Abs

orpt

ion

-0.01

0.00

0.01

0.02

0.03

0.04

0.05

0.06

1390 11

54

912

712

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IR analysis of atmosphericplasma polymerised BTSE at 50W, 10 min

Metal

Organic layer

Native oxide

System 1

⇒ Film contains organic groups


Wavenumber (cm-1)

800100012001400

Abs

orpt

ion

-0,01

0,00

0,01

0,02

0,03

0,04

0,05

0,06

10 min 5min15 min

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Influence of deposition time

⇒ Increasing deposition time results in thicker layers

(50 W)

1154 Si-O-C (-SiOCH2CH3)912 Si-O-C symmetric stretching (-SiOCH2CH3)712 C-H rocking


Metal

Organic layer

Native oxide

System 1


Wavenumber (cm-1)

7008009001000110012001300

Abso

rptio

n

0,00

0,01

0,02

0,03

0,04

0,0540 W 50 W 70 W80 W

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Influence of input power

⇒ Input power changes the amount of bonds and the chemical environment in the film

(10 min)



Metal

Organic layer

Native oxide

System 1


Wavenumber (cm-1)

7008009001000110012001300

Abso

rptio

n

0,00

0,01

0,02

0,03

0,04

0,0540 W 50 W 70 W80 W

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⇒ Input power changes the amount of bonds and the chemical environment in the film

(10 min)



Film properties ? Effect of plasma conditions on properties ?

Ongoing work….

Metal

Organic layer

Native oxide

System 1

Part 2.2: Vacuum plasma deposition

Aim:

- Step 1: Deposition of Si-oxide from hexamethyldisiloxane HMDSO

- Step 2: Deposition of organic layer of BTSE (similar to atmospheric plasma results; not shown)

System 2

Oxide

Metal

Organic layer

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System 2

Oxide

Metal

Organic layer

Coating material Hexamethyldisiloxane (HMDSO) solution

Gas discharge HMDSO or HMDSO+O2

Power 50 to 300 W

Deposition time 300 s, 600 s

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System 2

Oxide

Metal

Organic layer

Wavenumber (cm-1)

1000200030004000

Abs

orpt

ion

-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

1260

1100

800-

712

2960

-290

0

IR analysis of vacuum plasma polymerized coatingfrom HMDSO (300 W, 300 mT, 10 min)


2900-2960 C-H symmetric and asymmetric stretching (-CH3-)1260 CH3 symmetric bending ( -Si(CH3)x)1100 Si-O/-Si-O-Si- stretching790-800 -Si(CH3)n rocking

⇒ ‘oxide’ layer contains carbon groups

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System 2

Oxide

Metal

Organic layer

Wavenumber (cm-1)

800100012001400

Abso

rptio

n

0,00

0,02

0,04

0,06

0,08

0,10

0,1250 W100 W150 W200 W300 W

1260

1100

800-712

Wavenumber (cm-1)

280028502900295030003050

Abs

orpt

ion

0,00

0,01

0,02

0,03

0,04

0,05

50 W100 W150 W200 W300 W

2960-2900


⇒ Increased input power results in thicker deposition

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System 2

Oxide

Metal

Organic layer

Influence of oxygen addition to HMDSO plasma : 20% HMDSO / 80% O2(200 W, 300 mT, 10 min)

⇒ Less carbon groups; more Si-O formation

Wavenumber (cm-1)

1000200030004000A

bsor

ptio

n

0

1

2

3

4

5

6

1260

1100

800-7122960-2900


2900-2960 C-H symmetric and asymmetric stretching (-CH3-)1260 CH3 symmetric bending ( -Si(CH3)x)1100 Si-O/-Si-O-Si- stretching790-800 -Si(CH3)n rocking

⇒ Confirmed with XPS

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System 2

Oxide

Metal

Organic layer

⇒ Oxygen addition favours decomposition of the HMDSO in the plasma and the deposition of a purer, inorganic layer of Si-oxide

⇒ x% HMDSO / 100-x % O2 mixture

= variable for film property variations !

= formation of layers with variable level of carbon groups and inorganicspecies resulting in different (???) film properties

Film properties ? Effect of plasma conditions on properties ?

Ongoing work….

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Conclusions

⇒ different deposition methods and deposition conditions result in different types of films in terms of morphology and composition (organic, inorganic or mixed)

Film properties ?

Effect of processing conditions on properties ?

Ongoing work….

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comparison between wet deposition and plasma deposition of ... · deposition of silane coatings on...

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