Synthesis of Al2O3/SiO2nano-nano composite ceramics under high pressure and its inverse Hall-Petch behavior.

Gaida, Nico A., Nishiyama, Norimasa, Masuno, Atsunobu, Holzheid, Astrid, Ohfuji, Hiroaki, Schürmann, Ulrich, Szillus, Christin, Kulik, Eleonora, Bednarcik, Jozef, Beermann, Oliver, Giehl, Christopher and Kienle, Lorenz (2016) Synthesis of Al2O3/SiO2nano-nano composite ceramics under high pressure and its inverse Hall-Petch behavior. Journal of the American Ceramic Society, 100 (1). pp. 323-332. DOI 10.1111/jace.14551.

Full text not available from this repository.

Supplementary data:

Abstract

We report the synthesis of alumina/stishovite nano‐nano composite ceramics through a pressure‐induced dissociation in Al2SiO5 at a pressure of 15.6 GPa and temperatures of 1300°C‐1900°C. Stishovite is a high‐pressure polymorph of silica and the hardest known oxide at ambient conditions. The grain size of the composites increases with synthesis temperature from ~15 to ~750 nm. The composite is harder than alumina and the hardness increases with reducing grain size down to ~80 nm following a Hall–Petch relation. The maximum hardness with grain size of 81 nm is 23 ± 1 GPa. A softening with reducing grain size was observed below this grain size down to ~15 nm, which is known as inverse Hall–Petch behavior. The grain size dependence of the hardness might be explained by a composite model with a softer grain‐boundary phase.

Document Type: Article
Keywords: alumina hardness nanocomposites silica
Research affiliation: Kiel University > Kiel Marine Science
OceanRep > The Future Ocean - Cluster of Excellence
Kiel University
Refereed: Yes
Open Access Journal?: Yes
DOI etc.: 10.1111/jace.14551
ISSN: 0002-7820
Date Deposited: 19 Dec 2017 10:13
Last Modified: 22 May 2019 13:40
URI: http://oceanrep.geomar.de/id/eprint/40867

Actions (login required)

View Item View Item