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XPS studies of adhesion at organosilane/aluminum interfaces Leung, Yin-Ling
Abstract
The work in this thesis deals with silane to aluminum adhesion. Angular dependent X-ray photoelectron spectroscopy (ADXPS) with the bias potential technique is used for the first time to probe silane/aluminum interfaces, the investigation aims to find evidence of direct chemical bonding between the two materials. 7074-T6 aluminum alloy panels are subjected to two surface pre treatments: degreasing treatment and chemical etching treatment which affect exposure of the Al oxide above the metal. Uppermost, though, is a carbon layer. ADXPS measurements show that the surfaces formed from these two treatments have different morphologies: one has continuous carbon and the other has carbon in patchy form. These different morphologies give different behavior in the adhesion. The organosilanes y-glycidoxypropyltrimethoxysilane (y-GPS), y-aminopropyltrimethoxysilane (Y-APS), and ymercaptopropyltrimethoxysilane (y-MGPS) were deposited on to the Al panels, and ADXPS was used to characterize the interfaces, as well as the orientations of the organofunctional groups. The combination of ADXPS and the new negative biasing potential technique, proposed by Pertsin and Pashunin, showed the presence of an extra peak in the Al2p spectra for y-GPS and y-MGPS deposited on to chemically etched aluminum. This extra structure may indicate that direct Al-O-Si bonding occurs between these silanes and the aluminum oxide. No significant change for the Al2p peak is found when y-GPS is deposited on degreased aluminum. That indicates that the continuous carbonaceous overlayer limits the interaction between the silane and the degreased aluminum, while the patchy carbonaceous overlayer provides some carbon-free aluminum oxide for interaction with the silane. By contrast, y-APS shows no evidence for direct chemical bonding with aluminum in either acidic medium (pH=3.0) or alkaline medium (pH=10.4). The structures of the y-APS films deduced from the ADXPS measurements explain this aspect: in both these cases the sSi-OH ends cannot approach the Al-OH groups on the metal surface, so no direct interaction takes place.
Item Metadata
Title |
XPS studies of adhesion at organosilane/aluminum interfaces
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1992
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Description |
The work in this thesis deals with silane to aluminum adhesion. Angular
dependent X-ray photoelectron spectroscopy (ADXPS) with the bias potential technique
is used for the first time to probe silane/aluminum interfaces, the investigation aims to
find evidence of direct chemical bonding between the two materials.
7074-T6 aluminum alloy panels are subjected to two surface pre treatments:
degreasing treatment and chemical etching treatment which affect exposure of the Al
oxide above the metal. Uppermost, though, is a carbon layer. ADXPS measurements
show that the surfaces formed from these two treatments have different morphologies:
one has continuous carbon and the other has carbon in patchy form. These different
morphologies give different behavior in the adhesion. The organosilanes y-glycidoxypropyltrimethoxysilane
(y-GPS), y-aminopropyltrimethoxysilane (Y-APS), and ymercaptopropyltrimethoxysilane
(y-MGPS) were deposited on to the Al panels, and
ADXPS was used to characterize the interfaces, as well as the orientations of the
organofunctional groups.
The combination of ADXPS and the new negative biasing potential technique,
proposed by Pertsin and Pashunin, showed the presence of an extra peak in the Al2p
spectra for y-GPS and y-MGPS deposited on to chemically etched aluminum. This extra
structure may indicate that direct Al-O-Si bonding occurs between these silanes and the
aluminum oxide. No significant change for the Al2p peak is found when y-GPS is
deposited on degreased aluminum. That indicates that the continuous carbonaceous
overlayer limits the interaction between the silane and the degreased aluminum, while the
patchy carbonaceous overlayer provides some carbon-free aluminum oxide for
interaction with the silane. By contrast, y-APS shows no evidence for direct chemical
bonding with aluminum in either acidic medium (pH=3.0) or alkaline medium
(pH=10.4). The structures of the y-APS films deduced from the ADXPS measurements
explain this aspect: in both these cases the sSi-OH ends cannot approach the Al-OH
groups on the metal surface, so no direct interaction takes place.
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Extent |
2757912 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2008-12-17
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0061745
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1992-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.