In situ cracking of silica beads in the SEM and TEM - Effect of particle size on structure-property correlations

Journal article


Publication Details

Author(s): Paul J, Romeis S, Mackovic M, Marthala V, Herre P, Przybilla T, Hartmann M, Spiecker E, Schmidt J, Peukert W
Journal: Powder Technology
Publisher: Elsevier
Publication year: 2015
Volume: 270
Pages range: 337--347
ISSN: 0032-5910


Abstract


Stöber Fink Bohn (SFB) silica is a well-known colloidal system: monodisperse spherical particles are readily obtained by this wet chemical synthesis route. Despite the frequent application of SFB silica, its mechanical properties are not comprehensively understood. Within this account, size dependent mechanical properties of single SFB particles are systematically investigated using in situ SEM and TEM techniques: particle properties are addressed in the size range of 1.5 μm down to 200 nm. Both, untreated particles and heat treated particles densified at 1000 °C are investigated. Structural characterization by vibrational spectroscopy, by solid state nuclear magnetic resonance spectroscopy, by scanning electron microscopy and by focused ion beam machining allows correlating mechanical properties and the internal particle structure. For untreated particles comprised of a weakly cross-linked silica network a high degree of plasticity associated with low Young’s moduli and hardness values is found. At large strains only cracking without full fracture of the particles occurs, whereby the crack path is clearly linked to the synthesis conditions: for larger particles obtained from a multistep growth process cracks propagate along weak intraparticle interfaces and are deflected around an inner core structure. After the thermal treatment cross-linking of the silica network is significantly enhanced and Young’s moduli comparable to vitreous silica accompanied by increased hardness values are found. Only the smallest particles exhibit cracking; fracture into two or more pieces is distinguished for particles above 500 nm. It is found by SEM imaging that the relative occurrence of cracking into several pieces is increasing with size - a behaviour associated with the brittle to ductile transition of silica. By testing a large quantity of particles, statistical significance is ensured.



FAU Authors / FAU Editors

Hartmann, Martin Prof. Dr.
Professur für Katalyse
Herre, Patrick
Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik
Mackovic, Mirza Dr.-Ing.
Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)
Marthala, Venkata Dr.
Professur für Katalyse
Paul, Jonas
Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik
Peukert, Wolfgang Prof. Dr.-Ing.
Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik
Przybilla, Thomas
Professur für Werkstoffwissenschaften (Elektronenmikroskopie)
Romeis, Stefan Dr.-Ing.
Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik
Schmidt, Jochen Dr.
Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik
Spiecker, Erdmann Prof. Dr.
Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)


Additional Organisation
Exzellenz-Cluster Engineering of Advanced Materials
Interdisziplinäres Zentrum, Center for Nanoanalysis and Electron Microscopy (CENEM)
Graduiertenkolleg 1896/2 In situ Mikroskopie mit Elektronen, Röntgenstrahlen und Rastersonden
Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)


Research Fields

D Catalytic Materials
Exzellenz-Cluster Engineering of Advanced Materials
A1 Functional Particle Systems
Exzellenz-Cluster Engineering of Advanced Materials
A2 Nanoanalysis and Microscopy
Exzellenz-Cluster Engineering of Advanced Materials


How to cite

APA:
Paul, J., Romeis, S., Mackovic, M., Marthala, V., Herre, P., Przybilla, T.,... Peukert, W. (2015). In situ cracking of silica beads in the SEM and TEM - Effect of particle size on structure-property correlations. Powder Technology, 270, 337--347. https://dx.doi.org/10.1016/j.powtec.2014.10.026

MLA:
Paul, Jonas, et al. "In situ cracking of silica beads in the SEM and TEM - Effect of particle size on structure-property correlations." Powder Technology 270 (2015): 337--347.

BibTeX: 

Last updated on 2019-29-05 at 15:31