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Processing thin (<10 m), dense, flexible -Al2O3 films from nanopowders
VerfasserTakeuchi, Makoto ; Niedermaier, Matthias ; Jahnsohn, Monika ; Umehara, Noritsugu ; Laine, Richard M.
Erschienen in
Journal of the Ceramic Society of Japan, Tokyo, 2019, Jg. 127, H. 2, S. 81-89
ErschienenTokyo : Ceramic Society Japan, 2019
DokumenttypAufsatz in einer Zeitschrift
Schlagwörter (EN)Nanopowders / Thin films / Microstructure control / Alpha alumina / Flexible
URNurn:nbn:at:at-ubs:3-11317 Persistent Identifier (URN)
 Das Werk ist frei verfügbar
Processing thin (<10 m), dense, flexible -Al2O3 films from nanopowders [3.91 mb]
Zusammenfassung (Englisch)

Normally, it is very difficult to process thin ceramic films (<10 m) except by vapor deposition methods. This is because in traditional ceramics processing, initial powder particle sizes (typical average particle sizes, APSs >200 nm) make it difficult to realize mechanically robust thin films after sintering to full density due to excessive grain growth. One solution to this problem is to start with nanopowders (APSs <100 nm). Here we present efforts to use simple, easily available nano -Al2O3 (transition or t-Al2O3) nanopowders (NPs) to process the subject films. Thus t-Al2O3 NPs when properly dispersed, doped with 0.55 wt.% MgO and ball milled with a polymeric binder provide castable systems. Wire wound roller drawing/tape casting provides access to thin green films (1030 m) with 75 wt.% ceramic loadings. Following binder burnout and careful sintering to temperatures of up to 1500C/7 h/air but preferably slightly lesser conditions leads to dense 10 m films with average -Al2O3 grain sizes of 500800 nm. At higher MgO concentrations, spinel phase separates during sintering likely inhibiting grain growth. These relatively dense films are flexible and translucent. Such films, because of their flexibility, may offer utility as catalyst supports, electronic substrates or as hard facings for other materials.

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