Records |
Author |
van der Rest, A.; Idrissi, H.; Henry, F.; Favache, A.; Schryvers, D.; Proost, J.; Raskin, J.-P.; Van Overmeere, Q.; Pardoen, T. |
Title |
Mechanical behavior of ultrathin sputter deposited porous amorphous Al2O3 films |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Acta materialia |
Abbreviated Journal |
Acta Mater |
Volume |
125 |
Issue |
125 |
Pages |
27-37 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
The determination of the mechanical properties of porous amorphous Al2O3 thin films is essential to address reliability issues in wear-resistant, optical and electronic coating applications. Testing the mechanical properties of Al2O3 films thinner than 200 nm is challenging, and the link between the mechanical behavior and the microstructure of such films is largely unknown. Herein, we report on the elastic and viscoplastic mechanical properties of amorphous Al2O3 thin films synthesized by reactive magnetron sputtering using a combination of internal stress, nanoindentation, and on-chip uniaxial tensile testing, together with mechanical homogenization models to separate the effect of porosity from intrinsic variations of the response of the sound material. The porosity is made of voids with 2e30 nm diameter. The Young's modulus and hardness of the films decrease by a factor of two when the deposition pressure increases from 1.2 to 8 mTorr. The contribution of porosity was found to be small, and a change in the atomic structure of the amorphous Al2O3 matrix is hypothesized to be the main contributing factor. The activation volume associated to the viscoplastic deformation mechanism is around 100 Å3. Differences in the atomic structure of the films could not be revealed by electron diffraction, pointing to a minute effect of atomic arrangement on the elastic properties. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000394201500003 |
Publication Date |
2016-12-02 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1359-6454 |
ISBN |
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Additional Links ![sorted by Additional Links field, ascending order (up)](img/sort_asc.gif) |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
5.301 |
Times cited |
5 |
Open Access |
OpenAccess |
Notes |
This work has been funded by the Belgian Science Policy through the IAP 7/21 project. The support of the ‘Fonds Belge pour la Recherche dans l’Industrie et l’Agriculture (FRIA)’ for A.v.d.R. is also gratefully acknowledged, as well as the support of FNRS through the grant PDR T.0122.13 “Mecano”. |
Approved |
Most recent IF: 5.301 |
Call Number |
EMAT @ emat @ c:irua:138990 |
Serial |
4330 |
Permanent link to this record |
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Author |
Simonsen, K.P.; Poulsen, J.N.; Vanmeert, F.; Ryhl-Svendsen, M.; Bendix, J.; Sanyova, J.; Janssens, K.; Mederos-Henry, F. |
Title |
Formation of zinc oxalate from zinc white in various oil binding media: the influence of atmospheric carbon dioxide by reaction with 13CO2 |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Heritage science |
Abbreviated Journal |
|
Volume |
8 |
Issue |
1 |
Pages |
126 |
Keywords |
A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
Abstract |
The formation of metal oxalates in paintings has recently gained a great deal of interest within the field of heritage science as several types of oxalate compounds have been identified in oil paintings. The present work investigates the formation of metal oxalates in linseed oil in the presence of the artists' pigments zinc white, calcite, lead white, zinc yellow, chrome yellow, cadmium yellow, cobalt violet, and verdigris. The oil paint films were artificially photo-aged by exposure to UVA light at low and high relative humidity, and afterwards analysed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The results showed that, compared to the other pigments investigated, zinc white is especially prone to metal oxalate formation and that high humidity is a crucial factor in this process. Consequently, the reactivity and photo-aging of ZnO in various oil binding media was investigated further under simulated solar radiation and at high relative humidity levels. ATR-FTIR showed that zinc oxalate is formed in all oil binding media while X-ray powder diffraction (PXRD) revealed it was mainly present in an amorphous state. To examine whether atmospheric CO2(g) has any influence on the formation of zinc oxalate, experiments with isotopically enriched (CO2(g))-C-13 were performed. Based on ATR-FTIR measurements, neither (ZnC2O4)-C-13 nor (ZnCO3)-C-13 were formed which suggests that the carbon source for the oxalate formation is most likely the paint itself (and its oil component) and not the surrounding atmosphere. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000596527000001 |
Publication Date |
2020-12-07 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2050-7445 |
ISBN |
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Additional Links ![sorted by Additional Links field, ascending order (up)](img/sort_asc.gif) |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.5 |
Times cited |
|
Open Access |
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Notes |
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Approved |
Most recent IF: 2.5; 2020 IF: NA |
Call Number |
UA @ admin @ c:irua:174381 |
Serial |
7979 |
Permanent link to this record |