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Low‐Temperature Hydrothermal Synthesis of Yttrium‐Doped Zirconia Powders
Author(s) -
Tsukada Takayuki,
Venigalla Sridhar,
Morrone Augusto A.,
Adair James H.
Publication year - 1999
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.1151-2916.1999.tb01891.x
Subject(s) - yttrium , materials science , aqueous solution , crystallization , hydroxide , anhydrous , cubic zirconia , hydrothermal circulation , tetragonal crystal system , solubility , hydrate , phase (matter) , hydrothermal synthesis , inorganic chemistry , precipitation , chemical engineering , nuclear chemistry , chemistry , metallurgy , ceramic , organic chemistry , oxide , engineering , physics , meteorology
The feasibility of low‐temperature synthesis of yttrium‐doped zirconia (Y‐ZrO 2 ) crystalline powders in aqueous solutions at lessthan equal to100°C has been evaluated, and the hydrothermal crystallization mechanism for Y‐ZrO 2 powders also has been investigated. Coprecipitated (Y,Zr) hydroxide gel, mechanical mixtures of Y(OH) 3 and Zr(OH) 4 gel, and Y(OH) 3 gel have been reacted in boiling alkaline solutions. Coprecipitated (Y,Zr) hydroxide gel crystallized to cubic or tetragonal Y‐ZrO 2 at pH 13.9. The yttrium content in the powder synthesized from coprecipitated (Y,Zr) hydroxide is consistent with the initial precursor solution composition, as expected from the similarity in solubility of Zr(OH) ‐ 5 and Y(OH) ‐ 4 . A diffusionless mechanism for the transformation of the (Y,Zr) hydroxide gel to Y‐ZrO 2 is proposed, and the phase stability in aqueous solution is discussed in terms of an in situ crystallization model. It is also demonstrated through thermodynamic arguments with experimental verification that the stable form of the Y‐ZrO 2 at 25°C is the anhydrous phase, not the metal hydroxide as previously thought.