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Effects of Milling and Calcination Temperature on the Compressibility and Sinterability of a Nanocrystalline Al 2 O 3 –Y 3 Al 5 O 12 Composite Powder
Author(s) -
HassanzadehTabrizi Sayed Ali,
TaheriNassaj Ehsan
Publication year - 2008
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.1551-2916.2008.02727.x
Subject(s) - calcination , materials science , microstructure , sintering , nanocrystalline material , agglomerate , composite number , compaction , chemical engineering , amorphous solid , relative density , composite material , nanotechnology , chemistry , crystallography , catalysis , organic chemistry , engineering
In the present work, the effects of milling and calcination temperature on the compressibility and sinterability of a nanocrystalline Al 2 O 3 –Y 3 Al 5 O 12 composite powder prepared by an aqueous sol–gel method were investigated. The results showed that calcination temperature has a strong influence on the sinterability and final microstructure of amorphous powders. The lower calcination temperatures below 800°C resulted in the reduction of density and formation of a vermicular microstructure after sintering. It was also found that breaking of hard agglomerates into particles and smaller agglomerates after 1 h of milling leads to an increase in green density at the early stage of compaction when the rearrangement of particles is the dominant mechanism of the densification. The best‐performing sample was that calcined at 800°C and milled for 1 h, which yielded a relative density of 95% with a micronic/sub‐micronic microstructure after sintering at 1500°C.