Upload
victor-hamilton
View
213
Download
0
Tags:
Embed Size (px)
Citation preview
The Surface Analysis Laboratory
Cutting and Sputtering:
Getting to the Buried Interface
John F Watts
The Surface Analysis Laboratory
Department of Mechanical Engineering Sciences
2 July 2014
The Surface Analysis Laboratory
The Problem!
The Surface Analysis Laboratory
Inorganic Layers
J E Castle et al, Corr Sci, 16, 145-158, (1975)
The Surface Analysis Laboratory
High Temperature Oxidation
J C Rivière et al, Surf Sci, 117, 629, (1982)R K Wild, Spectrochim Acta, 40B, 827, (1985)
The Surface Analysis Laboratory
d
Interface Region
Substrate
Adhesive or Coating10’s m - mm
100’s m - mm
ARXPS d ~10nm
X-ray spectroscopies d ~200nm
RBS d ~1μm
Buried Interfaces: The Problem
One solution is mechanical sectioning of the sample
followed by analysis of the exposed interfacial region
The Surface Analysis Laboratory
The Buried Interface
Obtaining analytical information from intact interfaces is very difficult.
Carrying out in-situ experiments within the spectrometer can be useful but only rarely is the interphase chemistry exposed in this manner
J F Watts, Surf Interf Anal, 12, 497-503, (1988)
The Surface Analysis Laboratory
Oxide Stripping
Chemical removal of metal substrate, depth profiling of oxide in situ by ion sputtering. Interphase can then be analysed directly
J F Watts, J E Castle, J Mat Sci, 18, 2987, (1983)
The Surface Analysis Laboratory
XPS Spectrum at Interphase
Iron 2p3/2 spectrum showing Fe(II) component at interface. Oxide is entirely Fe(III).
Fe(II) satellite
Fe(II)
The Surface Analysis Laboratory
Model of Interphase
The Surface Analysis Laboratory
Complementary Dissolution
The Surface Analysis Laboratory
Energy Filtered TEM
(a) (b) Energy-filtered (PEELS) TEM images of adhesively bonded aluminium showing the interpenetration of organic and oxide phase that is achieved when a primer is used (a). In the absence of a primer (b) the adhesive merely forms a interfacial boundary with the oxide.
A J Kinloch, M Little, J F Watts, Acta Materialia, 48, 4543, (2000)
The Surface Analysis Laboratory
MICROM 355S
The Surface Analysis Laboratory
Ultra-Low Angle Microtomy
angled sectioning block
sample
polyethylene
Angle Sectioning Block
12 x 12 x 7 mm3
+ 25 m = 0.03O
+ 50 m = 0.07O
+ 100m = 0.15O
+ 200 m = 0.33O
microtome blade
The Surface Analysis Laboratory
ULAM Depth Profiling
Coating
Small area XPS analysis mode (100 m)
Substrate
XPS spot size/m
ULAM taper angle/o
0.03 0.33 2.0
100 60 600 3500
15 13 100 500
Depth Resolution ULAM/nm
S J Hinder, C Lowe, J T Maxted, J F Watts, J Mater Sci, 40, 285, (2005)
The Surface Analysis Laboratory
0
10
20
30
40
50
60
70
80
0 20 40 60 80 100 120 140 160
Depth / nm
Co
nc
en
tra
tio
n /
Ato
mic
%
C1s
O1s
N1s x10
F1s
PVdF (topcoat) Polyurethane (primer)
ULAM/Small Area XPS Depth Profile
S J Hinder, J F Watts, Surf Interf Anal, 36, 1032-1036, (2004).
The Surface Analysis Laboratory
ToF-SIMS of ULAM Interface
d)
b)a)
c)
1
3
2
+ve SIMS -ve SIMS
Polyurethane ions
PVdF ions
(a) m/z = 149: C8H5O3+
(b) m./z = 26: CN-
(c) m/z = 59: C3H4F+
(d) m/z = 19: F-
500 m
250 nm
S J Hinder, C Lowe, J T Maxted, J F Watts, Surf Interf Anal, 36, 1575, (2005)
The Surface Analysis Laboratory
0
500
1000
1500
2000
2500
3000
3500
0 20 40 60 80 100 120 140 160 180 200
m/z
Co
un
ts
a)25
41-4249
66
100
121
0
1500
3000
4500
6000
7500
9000
10500
12000
13500
15000
0 20 40 60 80 100 120 140 160 180 200
m/z
Co
un
ts
c) 19
49
39
85
Point 2: Bulk Polyurethane
Point 1: Bulk PVdF
c)
1
3
2
Negative SIMS Spectra from Images
The Surface Analysis Laboratory
0
200
400
600
800
1000
1200
1400
0 20 40 60 80 100 120 140 160 180 200
m/z
Co
un
ts
b)19
31
55 71
87
85
121185141
Point 3: PU and PVdF at Interfacec)
1
3
2
Reconstructed ToF-SIMS of Interphase
The Surface Analysis Laboratory
0
300
600
900
1200
1500
1800
2100
2400
2700
3000
30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
m/z
Co
un
ts
31
55
71
85
185
41
A negative ion ToF-SIMS mass spectra of the pure acrylic co-resin component of the PVdF topcoat
formulation in the mass range 30-200u
x10
ToF-SIMS of Acrylic Copolymer Component of PVdF Topcoat
The Surface Analysis Laboratory
a) b)
e) f)
d)c)
Negative Ion Mass
Selected Images
(a) m/z = 31: CH3O-
(b) m/z = 55: C3H3O-
(c) m/z = 71: C3H3O2-
(d) m/z = 85: C4H5O2-
(e) m/z = 87: C4H7O2-
(f) m/z = 141: C9H13O4-
Retrospective Images of Acrylic Ions
The Surface Analysis Laboratory
Model Specimen for ULAM
Adhesive
Aluminium foil
Adhesive
Line scanused
Interface Adhesive/Aluminium/Adhesive
Adhesive
M-L Abel, unpublished data (2008)
The Surface Analysis Laboratory
Polyamide Powder Coating + Aminosilane addition
ULAM is carried out on the intact outer surface to provide profile of air/coating interface and delaminated coating interfacial failure surface to provide steel/coating profile
100 mm thick thermoplastic polyamide powder coating with aminosilane added to the powder
stock prior to spray coating
M Guichenuy, J F Watts, M-L Abel, M Audenaert, Surf Interf Anal, 38, 168-171, (2006).
The Surface Analysis Laboratory
Aminosilane in PA11 Coating
92 94 96 98 1000
0.5
1
1.5
2
2.5
3
0 1 2 3
Depth / m
Ato
mic
%
//
Air/Coating Interface Coating/Steel Interface
0
1
3
4
2
Ato
mic
%
Depth / μm
100 m thick polyamide powder coating with aminosilane added to the powder stock prior to
spray coating
The Surface Analysis Laboratory
d
Interface Region
Substrate
Adhesive or Coating10’s m - mm
100’s m - mm
Deposit a very thin layer of organic phase
This may be from the plateau region of an adsorption isotherm
Thin Film Solution
Prepare specimen at monolayer coverage (i.e. plateau region) for XPS or ToF-SIMS analysisIt is then possible to probe interface chemistry directly
The Surface Analysis Laboratory
Organosilane Adhesion Promoters
Molecular Dynamics Models of:
(a) Epoxy (b)Amino(c) Vinyl
The Surface Analysis Laboratory
ToF-SIMS to Identify Specific Interactions
The intense SiOAl+
peak is indicative of a
covalent bond between
the aluminium oxide
and the organosilane
adhesion promoter
The Surface Analysis Laboratory
Conclusions A variety of “mechanical” and chemical methods to approach interfaces
ULAM provides an easy way to section samples at very low angles which has the potential to provide chemical depth profiles at very high depth resolution when used in conjunction with a surface analysis method such as XPS or ToF- SIMS
Polymer/polymer systems are straightforward, if the candidate substrate is metal a thin foil must be used
Thermosetting systems can be cut at ambient temperature, thermoplastic systems may need a cold stage