Title:
NANOCRYSTALLINE ALPHA ALUMINA (α-AI203) AND METHOD FOR MAKING THE SAME
Document Type and Number:
WIPO Patent Application WO/2018/075318
Kind Code:
A3
Abstract:
A process for producing metastable nanocrystalline alpha-alumina (α-Α1203) having particle sizes smaller than 12 nm. Starting crystallites of α-Α1203 having a particle size larger than 12 nm, typically on the order of about 50 nm, are ball-milled at low temperatures to produce a nanocrystalline α-Α1203 powder having a particle size of less than 12 nm, i.e., below the theoretical room temperature thermodynamic size limit at which α-Α1203 changes phase to γ-Α1203, wherein the powder remains in the α-Α1203 phase at all times.
Inventors:
WOLLMERSHAUSER JAMES (US)
DRAZIN JOHN (US)
KAZEROONI DANA (US)
FEIGELSON BORIS (US)
GORZKOWSKI EDWARD (US)
DRAZIN JOHN (US)
KAZEROONI DANA (US)
FEIGELSON BORIS (US)
GORZKOWSKI EDWARD (US)
Application Number:
PCT/US2017/056248
Publication Date:
August 02, 2018
Filing Date:
October 12, 2017
Export Citation:
Assignee:
US GOV SEC NAVY (US)
International Classes:
C01F7/023
Foreign References:
| US20090123362A1 | 2009-05-14 | |||
| US5284809A | 1994-02-08 | |||
| US20080308528A1 | 2008-12-18 |
Other References:
LEE, SANG-JIN ET AL.: "Fabrication of nanosized alumina powders by a simple polymer solution route", JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, vol. 6, no. 11, 2006, pages 3633 - 3636, XP009514100, ISSN: 1533-4880, DOI: 10.1166/jnn.2006.071
HESABI, Z. RAZAVI ET AL.: "An investigation on the compressibility of aluminum/nano-alumina composite powder prepared by blending and mechanical milling", MATERIALS SCIENCE AND ENGINEERING A, vol. 454, no. 455, 3 April 2007 (2007-04-03), pages 89 - 98, XP005933306
DRAZIN, J. W. ET AL.: "Reducing the size of nanocrystals below the thermodynamic size limit", CRYSTAL GROWTH & DESIGN, vol. 17, no. 4, 24 February 2017 (2017-02-24), pages 1752 - 1758, XP055522819
HESABI, Z. RAZAVI ET AL.: "An investigation on the compressibility of aluminum/nano-alumina composite powder prepared by blending and mechanical milling", MATERIALS SCIENCE AND ENGINEERING A, vol. 454, no. 455, 3 April 2007 (2007-04-03), pages 89 - 98, XP005933306
DRAZIN, J. W. ET AL.: "Reducing the size of nanocrystals below the thermodynamic size limit", CRYSTAL GROWTH & DESIGN, vol. 17, no. 4, 24 February 2017 (2017-02-24), pages 1752 - 1758, XP055522819
Attorney, Agent or Firm:
BROOME, Kerry, L. (US)
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