- Title
- Microcavity formation in alumina using Ti templates II: mechanism and kinetics
- Creator
- Hanson, Ronald E.; Kisi, Erich H.; Goodshaw, Heather J.; Forrester, Jennifer S.
- Relation
- Journal of the American Ceramic Society Vol. 92, Issue 6, p. 1339-1346
- Publisher Link
- http://dx.doi.org/10.1111/j.1551-2916.2009.03080.x
- Publisher
- Wiley-Blackwell Publishing
- Resource Type
- journal article
- Date
- 2009
- Description
- In part I of this work, it was found that titanium (Ti) wire encapsulated within mechanically milled alumina powder and sintered at 1350°C forms potentially useful microcavities due to the consolidation of Kirkendall porosity. Here a series of samples sintered at 1350°C in the range 0–24 h has shown the remarkable way in which these cavities form. The cavity has already started in samples quenched from the top of the heating ramp (0 min at 1350°C). It is surrounded by a diffusion zone ~300 μm in diameter, which does not change size throughout the firing process although the contents change markedly. The diffusion zone microstructure is initially complex with phase sequence TiO₂/Al₂O₃/TiO₂+Al₂O₃/Al₂TiO₅. Microstructure evolution may be summarized as outward growth of the cavity accompanied by inward growth of the Al₂TiO₅ resulting in a ~190-μm-diameter cavity surrounded by a 50-μm-thick layer of Al₂TiO₅. The formation of the cavity and surrounding microstructure is discussed although some features, such as the nucleation of Al₂TiO₅ in the part of the diffusion zone furthest from the Ti source and the ring of Al₂O₃, which persists in between Ti-rich parts of the diffusion zone are still poorly understood.
- Subject
- microcavity formation; alumina; kinetics; titanium templates
- Identifier
- uon:7542
- Identifier
- http://hdl.handle.net/1959.13/807900
- Identifier
- ISSN:0002-7820
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