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Synthesis of Bulk, Dense, Nanocrystalline Yttrium Aluminum Garnet from Amorphous Powders
Author(s) -
Sellappan Pathikumar,
Jayaram Vikram,
Chokshi Atul H.,
Divakar Canchi
Publication year - 2007
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2007.01913.x
Subject(s) - nanocrystalline material , materials science , yttrium , coprecipitation , amorphous solid , crystallization , microstructure , grain size , aluminium , porosity , metallurgy , relative density , mineralogy , hydrostatic pressure , composite material , chemical engineering , crystallography , nanotechnology , chemistry , engineering , oxide , physics , thermodynamics
Amorphous powders of Al 2 O 3 —37.5 mol% Y 2 O 3 (yttrium aluminum garnet (YAG)) were prepared by coprecipitation, decomposed at 800°C, and hot‐pressed uniaxally at low temperature (600°C) and a moderate pressure (750 MPa). Optimum conditions yielded microstructures with only 2% porosity and partial crystallization of YAG. Further processing using high quasi‐hydrostatic pressure (1 GPa) at 1000°C enabled the production of fully crystallized YAG with >96% relative density and a nanocrystalline grain size of ∼70 nm.