Les analyses de surface et l'adhésion - BELGIUM X. Vanden Eynde Centre de Recherches Métallurgiques (CRM) - GIS
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
Les analyses de surface et l’adhésion
X. Vanden Eynde
Centre de Recherches Métallurgiques (CRM)
BELGIUM
CoRI, 26/10/06Un lien fort entre la propriété macroscopique d’adhérence
et les mécanismes locaux d’adhésion
good bad bad
Les outils pour caractériser le défaut dépendront :
• du substrat
• de la taille
• du mécanisme d’adhésion
• du type de défaut
• de l’origine supposée du défaut ( organique ou inorganique)L’adhésion entre deux matériaux nécessite
un assemblage de plusieurs couches
Adhésif/revêtement
Couche atmosphérique
interphase
Oxyde/primaire
Ecrouissage
substrat
Les proportions relatives des différentes couches dépendent
des pré-traitements et du système (substrat/revêtement) utiliséUne combination intéressante d’outils analytiques pour
la caractérisation physico-chimique des surfaces
Surface (2-3nm) Depth
Depth Profiles Profiles
XPS SEM/SAM ToF-SIMS GDOES
Elements B< B< All All
Bonding states ✔✔ ✔ ✔✔✔ No
Sensitivity ✔ ✔ ✔✔✔ ✔✔✔
Quantification ✔✔✔ ✔✔ ✔ ✔✔
✔ ✔✔✔ ✔✔ No
Imaging
(~10µm) (~0.01µm) (~0.15µm)
Other techniques like IR spectroscopy, EDX analysis, C and S surface combustion,
atomic force microscopy (AFM), Contact angle (static and dynamic)Les traitements de surface • Modifications de surface d’acier et l’adhérence (effet du stockage) • La préparation de surface pour la galvanisation en continu • Cas où le mouillage et l’adhérence ne sont pas désirés • Préparation de surfaces galvanisées en milieu liquide
Tools to investigate
steel surface modification during storage
and adherence modification
X. Vanden Eynde, B. Schmitz, H. De Deurwaerder,
Centre de Recherches Métallurgiques (CRM)
Coating Research Institute (CoRI)
BELGIUM
CoRI, 26/10/06Tools for tuning surface
after continuous annealing lines
900
Water
800
quench or ...
700
Temperature (°C)
600
500
400
300 Rinsing or not
200 T Echantillon
Cde Regul
100
0
100 150 200 250 300 350
Time (sec)
Soaking N2-5%H2
DP-30°CThe surface microstructure is made of small oxalate crystals
IF without treatment IF treated with Oxalic ac.The surface composition is directly observed by XPS : iron oxalate
FeOx
Fesat ~2+ O-C=O Bidentate
Fe0
Fe2p3 C1s O1s
iron-carboxylate
600 2500
900 550
800 500 2000
450 C-(C,H)
700 400 1500
c/s
c/s
c/s
350 O-Fe
600
300 1000
500 250
200 500
400
150
300 100 0
740 720 700 300 290 280 545 535 525
BE (eV) BE (eV) BE (eV)
at.% Ratios
Theoretical Fe C O Fe/O Fe/C
Iron Carbonate FeCO3 20 20 60 0.33 0.33
Ferrous Oxalate 2+ Fe(C2O4) 14 29 57 0.25 0.51
+
Ferric Oxalate 3 Fe2(C2O4)3 10 30 60 0.17 0.50
Measurements
IF-Ti treated with Oxalic acid 13.7 29.7 53.1 0.26 0.56
IF-Ti treated with Oxalic acid (corrected) 13.7 26.5 53.1 0.26 0.50
Simulation performed with specific HOWAQ or POTC simulatorsAlthough the oxalate are still present after storage test, tarnishing is obvious
IF treated with Oxalic ac. IF treated with Oxalic ac. after HC
32 days
63.5 mm
26.5
mm
In climatic chamber with internal regulation of air at 40°C
and 95 % relative humidity
O-C=O
Fe2p3 Fesat ~3+ C1s
1500 600
550
1300 Oxalic ac. 500
1100 450
Oxalic ac. + H20
400
c/s
c/s
900 350
Oxalic ac.+HC
300
700
Oxalic ac. 250
500 +HC+H2O 200
150
300 100
740 720 700 292 287 282
Oxalate removes by rinsing
BE (eV) BE (eV)
before storageThe oxalate crystal morphology slightly affected by storage conditions
IF treated witout treatment
IF treated with Oxalic ac.
IF treated with Oxalic ac. after storage corrosion testThe acrylic acid treatment removes small selective oxides from the surface
without any crystal formation
IF without treatment IF treated with Acrylic ac.The steel surface is much less affected by storgae conditions, no tarnishing
IF treated with Acrylic ac. IF treated with Acrylic ac. after HC
32 days
63.5 mm
26.5
mm
In climatic chamber with internal regulation of air at 40°C
and 95 % relative humidity
Fe2p3 C1s
750
650 O-C=O
1000 Acrylic ac.
550
Acrylic ac. +H2O
750
c/s
c/s
450
Acrylic ac.+HC
350
Acrylic
500
ac.+HC+H2O
250
250 150
740 730 720 710 700 300 295 290 285 280
BE (eV) Impossible to remove BE (eV)
acrylates by water rinsingThe acrylic acid treatment removes small selective oxides from the surface
and creates a film onto the steel surface, which is affected by storage conditions
IF treated with Acrylic ac.The surface treatment can affect the storage behaviours
but also the adherence properties.
Waterborne (MPa) • AF : very clean surface
Reference 8X09 2.0 Adhesive
AF = Formic 5.2 Cohesive • GL, AG, AA : reactive surface
GL = Aminoacetic 4.9 ± 0.9 Cohesive • AO : reactive surface but with some
AG = Glycolic 3.8 ± 1.3 Cohesive remaining free AO at the surface
AA = Acrylic 4.5 ± 0.8 Cohesive
AO = Oxalic 1.5 ± 0.4 Cohesive
2-K water based epoxyThe surface treatment can affect the storage behaviours
but also the adherence properties.
Water based • For GL, AG, AO : active species removed
Not-rinsed Rinsed by rinsing but very clean surfaces
GL 4.9 ± 0.9 Coh 3.8 ± 1.0 Coh
AG** 3.8 ± 1.3 Coh 2.8 ± 0.7 Adh/Coh
• With AA, the active species remain
AA 4.5 ± 0.8 Coh 4.1 ± 0.3 Coh insoluble films and react
AO* 1.5 ± 0.4 Coh 3.9 ± 0.6 Coh with the paint components
2-K water based epoxy
Rinsed after storage in plastic bags under vacuumFast evolution of selective oxides at the steel surface under storage
There is a complete re-organisation of the manganese oxides
due to the thin water layer naturally present in humid air
IF-Mn-Si treated without treatment
AREA 1
0h 48h 184h
AREA 2The surface treatment can affect the storage behaviours
and also the adherence properties
• With XPS, it is possible to follow the chemical species along the process and how
these species are linked to the surface.
• Surface treatment can help by adding specific bonds or by getting a very clean surface
• The electronic microscopy and the corrosion experiments are necessary to
characterize the changes in surface morphologies (even for quite small features).Surface preparation for hot-dip galvanising
X. Vanden Eynde, L. Bordignon,,
Centre de Recherches Métallurgiques (CRM)
BELGIUM
Johann Strutzenberger, Alexander Jarosik, Josef Faderl
voestalpine Stahl GmbH
AUSTRIA
CoRI, 26/10/06Industrial problem
Zinc dewetting on an IF-B steel grade (10-3wt.%)
C Mn Si P Al Ti B
2 150 11 5.8 40 68 1.5
SCWE
Bulk microstructure by
Sometimes, SIMS, O2+, BO2- image (FoV:150µm)
Zn dewetting appears at the edges, the head and the queue of the coils
The coating adherence is drastically affected in dewetted regions
50µm
SAM-FEG image LOM 3-D imagingLaboratory facitilities
The XPS is equipped with an in-situ preparation chamber
in order to characterise surfaces after simulated processes
10 00
80 0
60 0
T (°C) 40 0
20 0
0
Main advantage :
Heat
0 50 10 0 15 0 20 0 2 50 Analysis of real
Tim e (s)
Treatments surface states
Controlled atmosphere XPS before galvanisation
UHV ex-situ or in-situ
Scanning Auger Microscope
Controlled atmosphere :
UHV, HNX, CO, NH3, ... ex-situ
and Dew Point (H2O) Secondary Ion Mass SpectrometryN2-5%H2 at 800°C for 60sec Laboratory study
Cold-rolled
35 70
XPS surface analyses
30 60
25 50 Mn Annealing in N2-5%H2
at.% (Fe, O)
Al at 800°C for 60sec induces
20 40
at.%
B
15 30
O
B and Mn external oxidation
10 20 Fe with a max at DP=-30°C
5 10
and no B oxide at DP= 10°C
0 0
-60 -10
Dew point (°C)
DP= -30°C AREA B1 O1 Mn1 Fe3
PT1 12.3 47.2 15.4 25.1
PT2 17.3 50.0 18.2 14.4
AREA3 0.0 69.2 0.0 30.8
1µm • nodules and needles at grain boundaries
• smaller nodules at the ferrite grain surface
SAM-FEG electron image • both are composed of Mn-B oxidesIndustrial problem
Boron profiles vary along the width
before annealing
GDOES depth profiles (33nm/s)
7 SIMS cross-section of axis sample
6 bulk level 20µm depleted
area
5 1st edge
Intensity (a.u.)
4
3 2nd edge
2 Axis
Cu
1 spacer
~20µm
0
SIMS, Cs+, B2- image (FoV:150µm)
0 200 400 600 800 1000
Sputtering time (s)
Boron depletion
more pronounced at the axis
The origin of such depletion
could be related to the hot-rolling
process parameters and practiceN2-5%H2 at 800°C for 60sec Laboratory study
Cold-rolled Polished (30µm)
35 70 35 70
XPS surface analyses
30 60 30 60
25 50 Mn 25 50
at.% (Fe, O)
at.% (Fe, O)
Al 20 40
20 40
at.%
at.%
B
15 30 15 30
O
10 20 Fe 10 20
5 10 5 10
0 0 0 0
-60 -10 -60 -10
Dew point (°C) Dew point (°C)
DP= -30°C
1µm 1µm
SAM-FEG electron imagesN2-5%H2 at 800°C for 60sec Laboratory study
Cold-rolled Polished (30µm)
35 70 35 70
XPS surface analyses
30 60 30 60
25 50 Mn 25 50
at.% (Fe, O)
at.% (Fe, O)
Al 20 40
20 40
at.%
at.%
B
15 30 15 30
O
10 20 Fe 10 20
5 10 5 10
0 0 0 0
-60 -10 -60 -10
Dew point (°C) Dew point (°C)
DP= -30°C
B mappings
1µm 1µm
SAM-FEG elemental mappingsWettability measurements Laboratory facilities
Correlation between surface states and zinc wetting
Sample annealed under desired conditions is transferred in-situ
to wetting force measurement device
0.8 Dynamic Θ 110
F (W)
γs
Wetting force (mN)
Wetting angle (°)
F (meas) 90
0.4
SAMPLE
N2-5%H2
A 70 Θ
DP-54°C
0.0
Θ 50
Static Θ
-0.4 30
Θ γl
Liquid bath
γi 0 5 10 15 20 25
Time (s)
F(meas.) = F(W) - F(A) = P γl cos Θ - F(A)
hot dipping at 460°C
in Zn-0.2wt% Al
High Θ bad wetting
Low Θ good wetting
cos Θ = (γ s - γ i) / γ lN2-5%H2 at 800°C with DP=-30°C Polished (30µm) Laboratory study
60 sec 600 sec 6000 sec
SEM
1µm
35 70 Soaking:820°C / 5%H2 / DP-30°C
30 60
80 120 Morphology
Mn 75 115
25 50 Si Static
Static wetting 20s (°)
Dynamic wetting (°)
at.% (Fe,O)
70 110
20 40 S
at.%
65 105
B
15 30 60 100
O
55
Dynamic
95
Wettability
10 20 Fe
50 90
5 10
45 85
0 0 Polished 3X01 steel grade
40 80
10 100 1000 10000 10 100 1000 Adherence
time (sec) Soaking time (s)Zn coating after oxidation/maturation shows good adherence
1-T bend test (strip thickness 1mm)
SEM image of bend part
TRIP Si
Oxidation N2-1%Air 650°C, 1 sec
Annealing in N2 with DP 0°C
Cooling in N2-10%H2
Same after scotch tape testZn coating after oxidation/maturation shows good adherence
TRIP Si
Oxidation N2-1%Air 650°C, 1 sec
Before the 1-T bend test
Annealing in N2 with DP 0°C
Cooling in N2-10%H2
1-T bend test (strip thickness 1mm)
SEM image of bend part
bend partThe surface compostion can affect liquid metal wetting and through the interface
homogeneity, the adherence
• With in-situ XPS, it is possible to follow the chemical species along the process and how
these species are linked to the surface.
• Complementary analysis with SIMS and GDOES with their high sensitivity indicates
composition variations
• The electronic microscopy shows the distribution at the surface before treatment or
after galvanising treatment
• Wetting measurements are related to the surface state and to the coating adherence
• The weak point is not always in the coating or at the interfaceYou can also read
