nanoceramics (rus. нанокерамика otherwise керамический наноструктурный материал) — a compact material based on oxides, carbides, nitrides, borides and other inorganic compounds comprised of crystallites (grains) with mean size ranging up to 100 nm.

Description

Nanoceramics are usually manufactured from nanoscale powders using forming and sintering techniques. As nanopowders are harder to compact due to intense internal friction, their compaction often involves methods including impulse and hydrostatic forming, slip and gel casting and fluid extrusion. One of the key challenges in manufacturing nanoceramics is usually the intensive growth of grain during sintering in normal conditions. Two basic methods are used to prevent this effect: addition to the base powder (blend) of insoluble doping agents that are localisised at the boundary of grains and prevent their coalescence, and the application of special methods and modes of compaction and sintering of ceramic materials that make it possible to significantly decrease the duration and/or temperature of high-heat manufacturing stages (impulse pressing, hot pressing, some types of presintering). All of these methods are described in more detail in the term entry "sintering of nanoceramics".

The structure-sensitive properties of nanoceramic materials may differ to a great extent from the properties of conventional ceramics with micron-size grain. Certain mechanical (Al2O3), electric (Y:ZrO2) or optical (Nd:Y2O3) properties may improve, but the nature of property changes depending on the size of grain is extremely subjective and is conditional on both the physical nature of a subject property and the physical-chemical features of the ceramics.

Illustrations

Change in the mean size of crystallites in nanoceramics bas
Change in the mean size of crystallites in nanoceramics based on ZrO2–CeO2–Al2O3 system in the temperature range of 400–1400 оС [2].

Authors

  • Ivanov Victor V.
  • Shlyakhtin Oleg A.

Sources

  1. Bagaev S.N., Kaminskijj A. A., Kopylov Ju.L., Kravchenko V. B. Oxyde laser nanoceramics: technology and perspective (in Russian) — http://rusnanotech08.rusnanoforum.ru/sadm_files/disk/Docs/1/46/1.pdf (reference date: 12.12.2011).
  2. T. I. Panova, M. Yu. Arsent’ev, L. V. Morozova and I. A. Drozdova. Synthesis and investigation of the structure of ceramic nanopowders in the ZrO2-CeO2-Al2O3 system // Glass Physics and Chemistry, Volume 36, Number 4, 470-477, DOI: 10.1134/S1087659610040115. — http://www.springerlink.com/content/au0700780225n247/fulltext.pdf (reference date: 12.12.2011).

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