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Hydration of magnesia cubes: a helium ion microscopy study

Schwaiger, Ruth 1; Schneider, Johannes; Bourret, Gilles R.; Diwald, Oliver
1 Karlsruhe Nano Micro Facility (KNMF), Karlsruher Institut für Technologie (KIT)

Abstract (englisch):

Physisorbed water originating from exposure to the ambient can have a strong impact on the structure and chemistry of oxide nanomaterials. The effect can be particularly pronounced when these oxides are in physical contact with a solid substrate such as the ones used for immobilization to perform electron or ion microscopy imaging. We used helium ion microscopy (HIM) and investigated morphological changes of vapor-phase-grown MgO cubes after vacuum annealing and pressing into foils of soft and high purity indium. The indium foils were either used as obtained or, for reference, subjected to vacuum drying. After four days of storage in the vacuum chamber of the microscope and at a base pressure of p < 10−7 mbar, we observed on these cubic particles the attack of residual physisorbed water molecules from the indium substrate. As a result, thin magnesium hydroxide layers spontaneously grew, giving rise to characteristic volume expansion effects, which depended on the size of the particles. Rounding of the originally sharp cube edges leads to a significant loss of the morphological definition specific to the MgO cubes. Comparison of different regions within one sample before and after exposure to liquid water reveals different transformation processes, such as the formation of Mg(OH)2 shells that act as diffusion barriers for MgO dissolution or the evolution of brucite nanosheets organized in characteristic flower-like microstructures. ... mehr


Volltext §
DOI: 10.5445/IR/1000060524
Originalveröffentlichung
DOI: 10.3762/bjnano.7.28
Scopus
Zitationen: 9
Web of Science
Zitationen: 9
Dimensions
Zitationen: 11
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Materialien - Werkstoff- und Biomechanik (IAM-WBM)
Karlsruhe Nano Micro Facility (KNMF)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2016
Sprache Englisch
Identifikator ISSN: 2190-4286
urn:nbn:de:swb:90-605248
KITopen-ID: 1000060524
HGF-Programm 43.22.01 (POF III, LK 01) Functionality by Design
Erschienen in Beilstein journal of nanotechnology
Verlag Beilstein-Institut
Band 7
Seiten 302-309
Schlagwörter helium ion microscopy, magnesia nanocubes, nanomaterials aging, oxide nanomaterials, surface hydroxylation, thin water films, volume expansion
Nachgewiesen in Dimensions
Scopus
Web of Science
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