Confinement creates a 9 GPa ambience: emergence of cristobalite phases in a silica film
IR@CGCRI: CSIR-Central Glass and Ceramic Research Institute, Kolkata
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Title |
Confinement creates a 9 GPa ambience: emergence of cristobalite phases in a silica film
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Creator |
Pramanik, Subrata
Ghosh, Jiten Chanda, Dipak Kumar Mukhopadhyay, Mrinmay Kumar Datta, Alokmay |
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Subject |
Engineering Materials
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Description |
We present here the results of the x-ray fluorescence (XRF), x-ray photoelectron spectroscopy (XPS), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive Analysis of x-rays (EDAX), x-ray Reflectivity (XRR), Secondary Ion Mass spectroscopy (SIMS) and x-ray Diffraction (XRD) studies of silica films spin-coated from a Tetraethyl Orthosilicate (TEOS) precursor on native and hydrophilized Al substrates. It is observed that the substrates are mainly porous (porosity similar to 33%) AlO(OH), there is a diffuse interlayer of highly porous (porosity similar to 90%) AlO(OH), essentially a modification of the substrate, and a top layer of silica composed of nanocrystals with in-plane dimensions of 100-300 nm and thickness of 2.5 nm with a sharply defined silica-hydrated alumina interface. The silica nanocrystals were found in the metastable high pressure cristobalite phases with the tetragonal or alpha-phase co-existing in its low (0.77 GPa) and high (9 GPa) pressure structures. This indicates a high normal stress developed from the confinement and provides a basis for the quantitative assessment of the confinement force, which comes out to be higher in value than the van der Waals force but weaker than the Hydrogen bonding force.
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Publisher |
IOP Publishing
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Date |
2021
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Type |
Article
PeerReviewed |
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Format |
application/pdf
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Identifier |
http://cgcri.csircentral.net/5252/1/subrata.pdf
Pramanik, Subrata and Ghosh, Jiten and Chanda, Dipak Kumar and Mukhopadhyay, Mrinmay Kumar and Datta, Alokmay (2021) Confinement creates a 9 GPa ambience: emergence of cristobalite phases in a silica film. Materials Research Express , 8 (6). Art No-066403. ISSN 2053-1591 |
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Relation |
http://cgcri.csircentral.net/5252/
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