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Fabrication of Transparent Yttria Ceramics by the Low‐Temperature Synthesis of Yttrium Hydroxide
Author(s) -
Ikegami Takayasu,
Li JiGuang,
Mori Toshiyuki,
Moriyoshi Yusuke
Publication year - 2002
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.1151-2916.2002.tb00342.x
Subject(s) - calcination , materials science , yttria stabilized zirconia , yttrium , chemical engineering , particle size , particle (ecology) , mineralogy , sintering , sulfate , inorganic chemistry , ceramic , cubic zirconia , metallurgy , chemistry , oxide , catalysis , organic chemistry , oceanography , engineering , geology
Thin flakes of yttrium hydroxide agglomerated in a manner resembling houses of cards with aging at 10°C. The agglomerate then dissociated into fine yttria particles with calcination at >800°C. The particle size of the calcined powder increased appreciably as the calcination temperature increased. The shrinkage curve indicated similar densification behavior among undoped yttria powders calcined at 800°–1000°C, despite considerable particle growth as the calcination temperature increased. Increasing the calcination temperature to >1000°C shifted the shrinkage curve appreciably to the high‐temperature region. Sulfate‐ion‐doped yttria particles had round edges, irrespective of calcination temperature, in contrast to the sharp edges of the undoped yttria particles. A calcination temperature of <1000°C resulted in skeleton yttria particles, which exhibited poor sinterability. At a calcination temperature >1000°C, the skeleton particles dissociated into monodispersed particles that densified easily. When the calcination temperature was >1000°C and the average particle sizes were similar, the undoped and sulfate‐ion‐doped yttria showed similar densification rates. The transparency of the sintered yttria ceramics was dependent on both the calcination temperature and sulfate‐ion doping: that is, sulfate‐ion doping and calcining at 1100°C were both necessary conditions for the fabrication of a transparent body.