Crack healing in glasses and glass matrix composites
- Fundamental understanding of crack healing in glassy crystalline materials is very important for solid oxide fuel cell (SOFC) sealants, since cracks caused by sealing or thermal cycling still remain a substantial bottleneck in developing durable SOFC. Previous studies on soda lime silicate glass [Sin14] showed that crack healing is driven by viscous flow and that healing progress is proportional to time t and inverse viscosity η. This finding would allow to present healing data of a given glass for different temperatures in a master curve healing progress versus t/η. Such master curves would be a helpful tool in understanding crack healing kinetics. Against this background, crack healing in non-crystallizing sodium calcium silicate (NCS) and sodium borosilicate glasses (NBS) have been studied. Moreover, to evaluate the influence of micro structure in crystallized glass on crack healing process, glass matrix composites (GMC) were prepared from NCS and zirconia as inert ceramicFundamental understanding of crack healing in glassy crystalline materials is very important for solid oxide fuel cell (SOFC) sealants, since cracks caused by sealing or thermal cycling still remain a substantial bottleneck in developing durable SOFC. Previous studies on soda lime silicate glass [Sin14] showed that crack healing is driven by viscous flow and that healing progress is proportional to time t and inverse viscosity η. This finding would allow to present healing data of a given glass for different temperatures in a master curve healing progress versus t/η. Such master curves would be a helpful tool in understanding crack healing kinetics. Against this background, crack healing in non-crystallizing sodium calcium silicate (NCS) and sodium borosilicate glasses (NBS) have been studied. Moreover, to evaluate the influence of micro structure in crystallized glass on crack healing process, glass matrix composites (GMC) were prepared from NCS and zirconia as inert ceramic filler material mimicking a partially crystalline micro structure. By this way, the micro structure can be kept constant during crack healing. Cracks were generated by Vickers indention and healed isothermally at different temperatures. Crack healing progress was monitored by optical and electron microscopy. Results show that the above mentioned proportionality actually applies for the studied glasses for which such a master curve could be obtained. In comparison to a non-crystallized glass, the effective viscosity of GMC is increased by the rigid filler content. This effect substantially retards crack broadening during later healing stages, which often ends up in large pores. On the other hand, local viscous crack healing is still possible in larger glassy regions. This behavior seems to be very interesting for crack healing optimized micro structures.…
Autor*innen: | Carsten BlaeßORCiD |
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Koautor*innen: | Cyrus Thompson, Ralf Müller |
Dokumenttyp: | Vortrag |
Veröffentlichungsform: | Präsentation |
Sprache: | Englisch |
Jahr der Erstveröffentlichung: | 2017 |
DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Angewandte Physik |
Freie Schlagwörter: | Crack healing; Glass; Glass ceramic; Microstructure |
Veranstaltung: | Crystallization 2017 |
Veranstaltungsort: | Segovia, Spain |
Beginndatum der Veranstaltung: | 10.09.2017 |
Enddatum der Veranstaltung: | 13.09.2017 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 04.10.2017 |
Referierte Publikation: | Nein |
Eingeladener Vortrag: | Nein |